UNITED STATES

NUCLEAR WASTE TECHNICAL REVIEW BOARD

SPRING 2004 BOARD MEETING

May 19, 2004

Embassy Suites Hotel

1250 22nd Street, NW.

Washington, D.C.

[NWTRB BOARD MEMBERS PRESENT]{.underline}

Dr. Mark Abkowitz

Dr. Daniel B. Bullen

Dr. Thure Cerling

Dr. Norman Christensen

Dr. David Duquette, Morning Session Chair

Dr. Ronald Latanision, Afternoon Session Chair

Dr. Priscilla Nelson

Dr. Richard Parizek

[SENIOR PROFESSIONAL STAFF]{.underline}

Dr. Carl Di Bella

Dr. Daniel Fehringer

Dr. Daniel Metlay

Dr. Leon Reiter

Dr. David Diodato

Dr. John Pye

[NWTRB STAFF]{.underline}

Dr. William D. Barnard, Executive Director

Karyn Severson, Director, External Affairs

Joyce Dory, Director of Admininstration

Linda Coultry, Management Assistant

Alvina Hayes, Office Assistant

[I N D E X]{.underline}

[PAGE NO]{.underline}.

**Call to Order and Opening Remarks**

David Duquette, NWTRB Member . . . . . . . . . . . 334

**Regulatory Requirements,**

Margaret Chu, Director, OCRWM. . . . . . . . . . . 334

**Introduction**

Robert Andrews, Manager Postclosure Safety,

Bechtel SAIC Company (BSC) . . . . . . . . . . . . 348

**Thermal Hydrological Environments and**

**Thermal Seepage**

Gudmundur Bodvarsson, Direction, Earth Sciences

Division, Lawrence Berkeley National Laboratory. . 375

**Dust and Salt Deliquescence During the**

**Thermal Pulse**

Carl Steefel, Geochemist, LBNL . . . . . . . . . . 438

**Thermal Chemistry and Evaporative**

**Concentration Evolution**

Carl Steefel, Geochemist, LBNL . . . . . . . . . . 501

**Corrosion of Alloy 22**

Joe Payer, Professor of. . . . . . . . . . . . . . 545

**Public Comment Period**. . . . . . . . . . . . . . . 629

**Summary**

Robert Andrews . . . . . . . . . . . . . . . . . . 639

**Wrap-Up Statements** . . . . . . . . . . . . . . . . 669

**Adjournment**. . . . . . . . . . . . . . . . . . . . 676

DUQUETTE: Good morning. For those of you who may be new\--there aren\'t
too many of you\--I\'m David Duquette, Chair of the Executive Committee
of the Board. We have a very busy day today, continuing on the erosion
behavior of the canister and thermal pulse. Most of the, I think all of
today\'s presentations will be by the Department of Energy and I\'m not
going to take too much time this morning except to say that I hope
before the day is over the environment at least will be described, the
environment that we\'re dealing with in this particular case, and
whether there is inhibition or not inhibition, whether the nitrate is
important or not important, whether the dust is acid or basic or
whatever the situation is. I hope all of that will be addressed this
morning. So, without any further adieu, I\'m going to introduce the
first speaker. Margaret, would you come up and make a few comments on
regulatory requirements?

CHU: Good morning. There are a lot less people today than yesterday.

DUQUETTE: Yes.

CHU: It was a long day yesterday. It\'s going to be longer.

You know, the reason I asked for 10 minutes to make a few remarks this
morning is\--can you hear okay? Okay. Well, ever since I received the
letter from the Board on October 21st, I have been thinking about a
statement in the letter, which actually turned out it was on the
Board\'s view graph yesterday. The quote, unquote, \"Total system
performance assessment should not be used to dismiss corrosion
concerns.\" But yesterday\'s presentation gave me a little more insight
as to what that means but it really is the reason I want to spend 10
minutes.

You know, I indicated in my response back to the Board that we would not
dismiss the corrosion concerns and I also pointed out that performance
assessment is a required part of the demonstration of compliance with
the safety requirements established by the NRC. And then, I would like
to take a few minutes today to expand on this point because I think
that\'s a very important point. I want to make sure we are all on the
same page.

You know, under the law, the repository has to meet a safety standard
defined by the EPA and implemented by NRC on 10 CFR 63. This standard is
philosophically okay. The framework is a risk-based\--no, I\'m sorry,
risk-informed\--the NRC, they don\'t like the word risk-based.
Risk-informed and performance-based standard. So I\'m going to kind of
dissect those two parts a little bit.

We all know the definition of risk. You know, we call it a risk triplet.
What it means is what can go wrong, how likely it is, and what is the
consequence. Everybody knows that.

So the regulation requires that we consider the probability as well as
the consequences of all features, events and processes that could affect
the performance of the repository. So this is the risk-informed part.

The second part is the performance-based. As for the performance-based
part, the regulation focuses on the overall performance of the
repository at a system level rather than on the behavior of the
individual components separately. As you all know, the post-closure
safety standard is an annual dose not exceeding 15 millirem to the
reasonably maximally exposed individual. So that is the overall system
level performance objective, 15 millirem dose.

And then there\'s another important point in 10 CFR 63. It requires us
to demonstrate that there is a reasonable expectation, not an absolute
certainty, that the repository will meet that standard, that
requirement, 15 millirem. Section 63.304 states that absolute proof is
impossible to obtain due to the uncertainty of projecting long-term
performance. 10,000 years is just too far for us to know for certain.
\"Reasonable expectation\", that quote in the rules, focuses on the full
range of defensible and reasonable parameter distributions. And then it
specifically says, please do not use extreme physical situations and
parameter values. And so, they recognize the uncertainty and say,
you\'re uncertain, you have to be defensible and reasonable. Don\'t go
to the extreme.

And then, last Fall there was a presentation from NRC\'s Chair, Mr.
Diaz, and he made a speech on this whole concept. He made a very good
point. He said if you go to the extreme, are ultra conservative, go to,
you know, the end point of a scenario, your answer is going to be masked
by that scenario and you actually would divert your resource on looking
at what\'s really important, what the real risks are. So, there is a
balance on how much uncertainty you put in. And so, you know, I
personally am pleased that we\'re starting to putting back, for example,
yesterday you heard the presentation on seismic end because that really
bothered me, when it\'s unlimited, unbound, because everybody knew that
it was unreasonable. We started to pull it back because the
reasonableness test is an important part.

So, and then the regulation says a total system performance, TSPA, is
required to project a long-term dose from releases from the repository.
So the regulations say this is how, you\'re going to show us how to
demonstrate our 15 millirem, okay, of the level.

And then please bear with me. I\'m going to quote you a little bit. NRC
describes performance assessment this way: He says \"It\'s a
systematic\--that\'s the important words\--systematic analysis that
identifies the features, events and processes that might affect
performance of the geological repository.\" You\'re supposed to examine
their effects on performance and estimate the radiological exposures,
including incorporating the probability that the estimated exposures
will occur to the reasonably maximally exposed individual during the
10,000-year compliance period.

The regulation also says, you know, if it\'s very unlikely then, less
than 10 to minus 8, never mind. Don\'t worry about that. Okay, so
there\'s some second tier.

So from this description is it clear that features, events and processes
are the underlying foundation for the development of a TSPA. So the TSPA
is the methodology used to roll up and integrate the effects of all the
features, events and processes, and to calculate their combined impact
on the expected dose. This roll-up takes into account the probability,
the consequences and the uncertainties. I know a lot of people know what
this TSPA, this composite thing means. It is a different concept because
the final result of TSPA is a distribution of outcome. There\'s no
single story in the final outcome of TSPA. You can\'t say, you can\'t
shoot a movie paid from time zero to time 10,000 years, say this is what
I expect will happen. Rather, it\'s a combination of a possible spectrum
of evolution, of the behavior of the repository. So it\'s a composite
story you\'ve got to see because we can\'t predict something uncertain,
so we can\'t describe the evolution and say this is how many packages is
going to corrode because of this and that because spectrum things can
happen. There are certainty of chemical condition, you know, and
everything, so therefore, so when you do TSPA, you take that
uncertainty, the probability of consideration, you sample them, that
reflects the uncertainty and probability and then you roll all of them
up. All of a sudden you see this big distribution of dose, and then this
is really representing this whole spectrum of possibilities.

So my point is TSPA itself cannot be used to dismiss anything. If you do
it right, okay? One can argue and debate on the technical basis, or the
lack of it, of underlying processes that are used to\--you know, before
it got rolled up. And this is what we\'re doing later today, is the
individual processes that we are presenting.

And then this important point: If a process is important to the overall
safety of the repository in this composite picture, you will and should
show up as important to the TSPA, unless you do it right, unless the
technical basis is important. And, if something is important to certain
conditions, but if it turns out that it\'s a minor effect out of the
whole scheme, you would not show up as very impacting in the big
picture.

In fact, you know, a detailed understanding of the importance of a
particular engineered or natural of the are to the performance of the
overall repository system is frequently best understood through TSPA. I
remember when I was working on WIPP, we used TSPA to determine data
sufficiency, to determine, to prioritize R and D work, and so on.
Because it can be a very powerful tool to put you in the right
perspective at the system.

After saying all that, TSPA is not the only factor in compliance
determination by NRC. NRC will also consider several other important
factors. The first one is multiple barriers. NRC says because of the
inherent uncertainties, the natural barrier and the engineered barrier
system need to work in combination to enhance the resiliency of the
geological repository. So therefore, if some component turns out it\'s
not important to TSPA\--waste pack for example, that there\'s some
questions, can you ignore it? No. NRC says you have to have that because
of multiple barrier concept.

Now the second factor is the Quality Assurance Program, and we\'re all
very familiar\--I want to make sure absolutely sure you have done what
you say you have done, it\'s well documented, following this rigorous
procedure. So that\'s the confidence NRC needs to have.

The third factor is the performance confirmation program. Is that you
have putting all these assumptions in the data and analysis in your
license application. It may look good during the license application
time, and then they require us to plan a long-term performance

confirmation program and say we want verification, we want you to
monitor the important assumptions in data, so we know because 50 years
down the road, we know there\'s nothing wrong.

And finally, you all remember that there\'s a retrievability program
required by NRC in case everything you have done is wrong, okay? People
all did the wrong stuff. They want to have a retrievability option open,
can always go and retrieve everything so there will be no disasters. So
this is sort of the whole scheme of the philosophy of 10 CFR 63.

Now, today we\'re going to focus on some of the key corrosion-related
processes that are considered in the TSPA. You\'re going to hear today
what we consider as the technical basis for the treatment of the
in-drift environment and corrosion.

I want to re-emphasize that the fact that a process like certain waste
package corrosion mechanisms might occur in the repository justifies the
inclusion of the process in the determination of compliance with safety
requirements. However, the existence of such a process does not by
itself determine whether the repository will or will not comply with the
standard. Both the probability and the consequences of that process,
together with associated uncertainties must be taken into account
through the TSPA to determine how important that particular process is
in the context of all other processes that contribute to the total risk
from the repository. So I just want to remind everybody, today is very
important. Corrosion is a very important mechanism. But it is the one
process out of very many eventually we have to roll out. And then, this
is the essence of the risk-informed performance-based standard that the
repository must meet.

So in conclusion, you will hear technical presentations related to
corrosion during thermal period later, we will not present TSPA today.
However, today\'s presentations are the underlying processes that we
will need to roll up together with all other possible processes into the
TSPA. And we will discuss the TSPA conclusions in more detail when we
present our work to the Board in our September meeting. Thank you.

Any questions? Is my time up?

DUQUETTE: Duquette, Board. Margaret, thank you very much for your
comments. I\'m speaking for myself when I say this, certainly not the
Board. But I don\'t think you should take the comment in the letter
about TSPA out of context. I don\'t think anyone on the Board wants to
dismiss TSPA under any circumstances. I think the letter identifies a
potentially avoidable problem with the repository. And, I think that was
really the thrust of the letter. Again, based on information that had
been given to us, it isn\'t clear, for example, whether the environment
will inhibit corrosion. The data that was available to us both from the
center in San Antonio and from your own researchers who indicated that
there was a potential for corrosion. I think that\'s all the letter
identifies at this particular point. I\'m really glad to see the effort
that the department, that EPRI, the other, that the state and NRC to put
into addressing this problem. But I want to say one more time it\'s my
opinion that TSPA is not dismissed by the Board under any circumstances.
We fully understand that TSPA can be satisfied without even considering
the corrosion issue, but I as an individual am very concerned about
compromising any of the barriers if it can be avoided. And that really
is where I think the letter was coming from.

CHU: Thank you, and, like I say, yesterday morning, and we really
appreciate that, and it really helped us to focus some the work, new
work, we\'re actually turning out some new work to address some of the
issues. And what I want to emphasize today is these are eventually,
it\'s due to roll-up of all the process that\'s going to determine the
ultimate outcome, but of course, in the meantime, we want to have the
best technical defense of all the underlying processes. Corrosion is a
prime, critical process that we are addressing. You know, we take those
technical issues very seriously.

DUQUETTE: Thank you, Margaret.

CHU: Thank you.

DUQUETTE: Dr. Latanision?

LATANISION: Latanision, Board. I just want to echo what Dave Duquette
has said. You know, as an engineer I\'m pretty pragmatic and I look at
TSPA as being obviously a very important and powerful tool, but if I\'m
in a position where I have the choice as an engineer of avoiding a
problem, which I believe I can do through a design decision, and I have
as the alternative using a predictive model, a predictive process to
help me in assessing whether some event has a high or low probability
and what the consequences might be, I\'m more apt to choose to avoid the
problem.

CHU: I understand.

LATANISION: And I think that\'s really in a nutshell where we\'re at. I
mean it\'s not dismissing the importance of TSPA. We recognize that
it\'s an important tool, it\'s part of the compliance process and we\'re
fully on-board in that context.

CHU: I fully appreciate that point. Thanks.

MR. LATANISION: Thank you.

DUQUETTE: Thank you, Margaret.

CHU: Thank you.

DUQUETTE: I think we\'ll get the meeting back on schedule. The next
presentation is an introduction to presentations addressing the Nuclear
Waste Technical Review Board\'s comments in a November 25th, 2003
letter, which is what we\'re talking about. That\'s going to be
presented

by\--Robert or Bob?

ANDREWS: Bob.

DUQUETTE: Bob Andrews. Okay.

ANDREWS: Okay, thank you and good morning. It\'s an honor and pleasure
to be here to introduce these three fine young men who are going to be
following me with the actual technical discussions. You can pay me later
for the compliment. Bo, Carl and Joe, and I\'ll talk about what they are
going to say as an introduction and they will provide the technical
details and bases for their conclusions and the additional data and
analyses that have been conducted, not only to address the Board\'s
questions but to address, more importantly, the role of the environment
and the role of the waste package and the corrosion degradation
mechanisms as they affect the repository facility, not only from a
performance assessment, a total system performance assessment
perspective, but from how it\'s going to be documented in the safety and
analysis report that John Arthur talked to you about yesterday.

So if I can have my first slide.  What I want to do is just give the
background, which I think was gone over a little bit yesterday, but I
want to go sort of point by point through the sequence of events that
led us to the November\--led us all to the November 25th letter, and to
today, essentially, go to what we\'re going to talk about today and what
we\'re not going to talk about today, and then introduce the subject
matter and the speakers in the context of comments made in the letter
itself, and in the executive summary of that letter so we can put it
into direct focus with respect to the comments that we are addressing
today. Next slide, please.

As was discussed yesterday, the Board was presented with a lot of
information last January, January, 2003, and May of 2003. January kind
of focused on corrosion, corrosion testing, information available as of
January of 2003 with respect to corrosion testing in a range of
environments.

That was followed up by the May presentations which generally focused on
three parts, which focused on seepage in a nature environment that
affects seepage into drifts because if there is no seepage then the
effects of the chemistry in the rock are somewhat mitigated because the
chemistry of the rock never get into the drift. So we had the discussion
on seepage and thermal seepage. We followed that with a discussion on
chemistry, chemistry in the rock and chemistry in the drift and the
evolution of that chemistry in the rock and in the drift as it affects
the degradation modes of the materials that are in the drift.

Then we followed that with a third presentation in May on the data
available at that time on testing in a range of environments with
localized corrosion testing, crevice corrosion and general corrosion and
evaluations of Alloy 22 degradation in the range of environments.

Those presentations the board commented on in a letter in June
identifying some potential questions, potential, I think the way they
phrased it was some initial reactions associated with the presentations
that were in May. I think the department then\--next slide,
John\--responded to that in October concluding that there was
insignificant corrosion above the boiling point, in large part, due to
the lack of seepage during the thermal period, and the primarily benign
deliquescent brines. When things did deliquesce, those brines were
generally of a non-corrosive nature, i.e., high in nitrate
concentration. And they also acknowledge, or the Department acknowledged
that there was insignificant corrosion below the boiling point of water
primarily because of benign seepage conditions. So when you got to that
point in the thermal hydrologic evolution where seepage could occur, the
chemistry of the fluids in the rock that could come into contact with
materials in the drift was also benign.

October 21st, the board provided a letter to the department summarizing
their conclusions related to corrosion. October 27th, we responded
noting that the corrosion testing that was presented at the May meeting
and some subsequent testing that I think had been provided to the Board
subsequent to that May meeting through its series of interchanges with
the Board provided an incomplete picture of the overall corrosion story
in the range of likely environments that should be considered.

On November 25th, the board did write their report which they had
mentioned in the October letter, and it\'s that report with its
conclusions that we want to address today. It had a cover letter and
then the actual body of the report, and as noted yesterday, there was an
attachment to the report by one of the board members acknowledging three
other issues that he felt were relevant to the discussion of
deliquescent brines and the effects, potential effects of deliquescent
brines on the performance.

So today, what we want to do is answer the questions, the concerns, the
issues raised in that November 25th transmittal from the board to the
department and to particularly focus on those aspects during the thermal
pulse, as it has been described, although we haven\'t defined thermal
pulse. The repository is in a thermal period for its whole time period,
will be in a thermal period through its whole time period no matter what
thermal loading strategy might be, so we will focus on information that
affects repository performance during the whole thermal period today.

We\'ve broken this series of presentations into four presentations, and
let me walk through the logic of why we broke it into four. First off,
the degradation characteristics of Alloy 22, I think everybody
acknowledges our function of the environment in which the waste package
sits. That environment is a thermal environment, it\'s a hydrologic
environment, it\'s a chemical environment, and in fact, it\'s a
mechanical environment as well. And those thermal, hydromechanical
processes and conditions do affect the degradation characteristics of
the Alloy 22, as do some other engineering aspects associated with the
formation, construction, fabrication of the waste package itself.

So, but we don\'t want to jump into Alloy 22 degradation. We want to put
it into the context of the environment in which it sits. That
environment is, first off, affected by the chemical environment but the
chemical environment is in fact affected by the thermal environment. And
we broke the chemical environment discussion into two separate parts
that Carl is going to talk about. The part this afternoon is reserved
for kind of the aqueous chemistry, the chemistry evolution in the rock
and the chemistry evolution in the drift in an aqueous type environment,
i.e., generally in the below-boiling type conditions.

This morning we\'re going to directly focus, because the board\'s letter
and executive summary focused on the deliquescent part of the chemistry.
That is the period when it is not only dry, there\'s not aqueous
conditions from the rock in the drift, but that we do have dust and dust
will deliquesce. Salts in the dust will deliquesce at a range of
different humidities and have different conditions with respect to the
corrosion mechanisms on Alloy 22.

So Carl Steefel will talk specifically about the dust issue, the
chemistry of the dust within the thermal hydrologic environment that
exists in the drift because you cannot separate how the dust behaves
from the temperature and humidity conditions in which that dust and the
salts within that dust are sitting. So we wanted to walk through the
hydrology and thermal hydrology first, then go to the dust part of the
chemistry second, go to the aqueous part of the chemistry third and
finally wrap it up with what does all those environment issues mean with
respect to the degradation characteristics of Alloy 22. And then I will
have some concluding comments at the end of the day.

If I can go to the next slide.

In addition to talking about what we are going to talk about, it\'s
useful to talk about what we\'re not going to talk about so we can also
put this into context.

We\'re not going to discuss all of the board\'s questions in the report.
Our aim was in the time allotted today was to focus on what was deemed
to be the most crucial aspects in the cover letter and in the executive
summary, which was the deliquescence of brines and thermal evolution
that affects that deliquescent of salts in the repository environment
during thermal pulse.

So there are a number of other aspects raised in the Board\'s letter,
and we\'re not going to focus on\--or the report, I should say, and
we\'re not going to focus on a number of those other elements. We would
be pleased to do that at a later time if desired by the Board.

We\'re also not going to focus on other elements of repository
performance. I\'m going to have a brief introduction to some of them
here in a few slides, but our focus is not on other elements of the
system. I think the Board recognized both in the cover letter and in the
report itself that there are other elements of the system that affect
the overall repository performance, that were also not the focus of that
letter, that could affect the results of the total system performance
assessment, and in fact do affect the results. So we\'re not going to
discuss those.

And I think it\'s also important to point out that we\'re not going to
discuss the low probability, disruptive type events that could affect
the characteristics of the drift after the repository is closed. One of
those we talked about a little bit yesterday. That\'s the seismic event.
We talked about the initiation part of the seismic event yesterday, the
consequences, the effects and consequences of a seismic event,
potentially a low probability seismic and high velocity seismic event
which can affect the degradation of the drift and can affect the thermal
environment and can affect the performance of the drip shield and the
waste package in that environment, are not going to be discussed. Our
focus is on the most likely performance, i.e., the probabilities of 99
percent, 99.9 percent of the time, not the .1 percent of the time that
may occur if a 10 to the minus six seismic event, for example, occurred
in the first thousand years of repository operation. So our focus is
going to be on what we think is the most likely and the uncertainty in
that most likely occurrence, not the low probability features, events,
things that also have to be considered in the post-performance
assessment.

And I\'m going to say that we have a day here. And a day might seem a
long time, but I can tell you each one of these speakers, we had to trim
down their stuff to get it into a day. So there is additional
information available. That additional information is being provided in
the updates of the analysis and model reports that John Arthur talked
about yesterday, and actually would be included in the SAR, the safety
analysis report. So, we\'re focused on answering the Board\'s questions
in the time allotted and there is additional information available that
sometimes the members will talk to. Next slide.

Okay, it\'s probably useful to put this into some overall context. I
don\'t want to say system performance assessment, but a system\'s
context, to first acknowledge that the whole repository system is built
of a large number of features and those features act as barriers and
there are three requirements for barriers. Has nothing to do with system
performance, but has to do with keeping water away from the waste,
limiting radionuclide release and delaying radionuclide transports, so
there are a number of features in this system that provide one or more
of those functions from a repository performance perspective.

We\'re going to focus in on one of those features today. That feature is
the waste package, effectively. And that waste package is affected by
the environment in which it sits. It is affected by the Allow 22
degradation, it\'s affected by the temperature, by the humidity, by the
hydrology, by the mechanics, i.e., the stresses that it sees, and by the
chemistry. But we\'re not going to talk about the other features, but
rest assured those other features and components are included in the
overall post-closure safety analysis that will be described in the
safety and analysis report.

Within each of those features, and in particular the features in the
drift, there are a number of processes. Thermal mechanical, hydrologic
chemical processes that go on. They go on with time. They will go on
with time no matter what design is chosen for this facility, things will
evolve. Temperatures will evolve, chemistries will evolve, hydrology
will evolve. Take a simple example of climate. We know climate will
change and the evolution of that climate change has to be factored in
and included in the assessment of how the repository behaves during the
10,000- year regulatory time period.

These processes are all describe by models. Those models are built on
data. Those data are, in some cases, in-situ data when that\'s
available, sometimes by laboratory test type data, sometimes by analog
information, and sometimes by other literature information. And in some
cases those models are substantiated and supported by other lines of
evidence including work done by others. And some of our presenters today
will present some work done by others, not the project, to support and
evaluate the applicability of their models with respect to other
people\'s tests.

Bo, for example will talk about some tests done at the Center with
respect to thermal hydrology and thermal seepage, and a comparison of
our model with their test and its information and the relevance of that
test and information to our projections of repository behavior.

Joe will present some information also from the Center on their testing
with respect to localized corrosion and critical potentials and
corrosion potentials.

Carl will present some information from Catholic University and the
relevance of that with respect to the environments that we think are
going to evolve within the drift. So we\'re not just using our own data
and information, we\'re using that information that\'s available from
others as a comparison and a test, if you will, of our own models and
analyses.

There is uncertainty in all of the above. All of the models have
uncertainty, the data have uncertainty, the parameters have uncertainty,
and those uncertainties need to be addressed in the assessment of
compliance with the Part 63 requirements.

There\'s also, as I said earlier, some unlikely events that have to be
assessed if their probability is greater than 10 to the minus 4 of
occurring during the 10,000-year time period. And all of that, as
Margaret said, has to ultimately be rolled up into an assessment of risk
because the compliance measure for Part 63, for Yucca Mountain, is a
risk-based performance type standard, so the uncertainties, the low
likelihood of features and events have to be considered and addressed
and included or appropriately excluded from the assessment of the
repository performance.

So if I can go on to the next slide. And what I\'m going to do is on the
left side have the actual Board\'s quotes from either the executive
summary or from the letter itself, I think Dr. Latanision yesterday
morning summarized the Board comments and I think the speakers, Dr.
Cerling followed that up with then summaries of these, but I\'ve put the
actual quotes that are going to be the focus of our following
discussion.

Okay, I think I will read these actually, even though they are up there.
\"The Board believes\"\--this is in the cover letter\--\"that all the
conditions necessary to initiate localized corrosion of the waste
package will likely be present during the thermal pulse because of the
deliquescence of salts on waste package surfaces, and thus it is likely
that deliquescence-induced localized corrosion will be initiated during
the thermal pulse.\"

They go on to say, \"Limited data examined to date indicate that dust,
which would be present on the proposed tunnels and which would be
deposited on waste packages, contains calcium chloride and magnesium
chloride salts in amounts sufficient for the development of concentrated
brines through deliquescence.\"

And finally, \"Corrosion experiments indicate that localized corrosion
is likely to be initiated if waste package surface temperatures are
above 140 C and if concentrated brines such as would be formed by the
deliquescence of calcium and magnesium chloride are present.\"

So for each one of those, we\'ve broken it up into the relevant parts of
those sentences and the relevant parts of the talks. It\'s impossible to
talk about deliquescence of salts without understanding the temperature
and humidity in which those salts are sitting. So Bo will present the
hydrology part, including the temperature and humidity and the range of
likely temperature, humidity profiles that are existent in the rock.
And, in the drift on the package.

And, it\'s important to put those into context. These are results that
are plotted in a little bit different way. We\'ll see when you get to
the presentations and what we\'ve presented last May, fundamentally they
are the same. There\'s a little more uncertainty included in thermal
hydrologic response that Bo will talk about, but we\'re going to plot
them as temperature humidity profiles rather than temperature time or
humidity time profiles because each package will essentially see its own
temperature/humidity relationship and it\'s that package and its
response to that temperature and humidity that\'s in fact important that
we want to talk about. So Bo will put that into context, so stay tuned
for the temperature and humidity relationships as they change with time
through the repository life.

Carl will then present information that neither calcium nor magnesium
chloride salts are present in the Yucca Mountain dusts. So the premise
that there are calcium chloride or magnesium chloride salts sitting on
the package Carl will discuss and discuss why that\'s not true.

Carl will also present information that, even if those salts existed in
our environment so we had calcium chloride or magnesium chloride salt
sitting on the waste package that would quickly transition to a more
stable phase, either through acid gas evolution at higher temperatures
or even under nominal temperatures and humidities, i.e., ambient
temperatures and humidity. It would evolve into a more stable phase.

Joe will then present information that, given those conditions, that the
probability of localized corrosion being initiated during this time
period is extremely low and that widespread corrosion, localized
corrosion as discussed in the Board\'s comment does not occur, for a
variety of reasons, and Joe will present the data that support those
conclusions.

Going on to the next Board comment in the executive summary, the Board
had comments associated with the thermal effects, and I\'m presenting
this in the order that they are in the letter rather than ranging it by
temperature and chemistry and corrosion because that\'s the way the
letter was written. \"The board believes that temperature calculations
may be inaccurate because (1) the DOE\'s rock mass thermal conductivity
estimates for the lower lith may be too high, the insulating effect of
rockfall and drift degradation are not included and the effects of
in-drift, in-rock natural ventilation and air circulation have not been
accounted for.\"

Bo will present additional information today with respect to the thermal
conductivity and the incorporation of thermal conductivity and its
uncertainty in the projections of the thermal hydrologic response. Mark
presented some of the data upon which Bo will describe the models
yesterday and those data are data available in the lower lith at a range
of different scales. Bo will also talk about the scale effect and the
appropriateness of scale when analyzing the thermal hydrologic response
over the scale of meters and tens of meters rather than centimeters or
tens of centimeters.

Bo will also discuss how the effects of drift degradation, especially
the high probability drift degradation effects are included and
addressed within the thermal hydrologic and thermal seepage and seepage
assessments themselves.

Bo will not discuss, as I said earlier, the effects of the very low
probability of drift degradation responses. I think it\'s fair to say
that extremely low probabilities of 10 to the minus 6 over, per year
which is 10 to the minus 2 over the lifetime of the repository at very
high peak ground velocities. I think the Board has been presented
results in the past that show that drifts can have a significant degree
of degradation. The probability of that occurring during the thermal
pulse, during, let\'s just say for the first 1,000 years, to make our
calculation easier, is .1 percent. So we\'re going to focus, as I said,
on the 99.9 percent of the time, not that .1 percent of the time.

And finally, with respect to in-drift convection and natural convection,
the effects of in-drift convection we\'re not going to talk about. There
are condensation effects. We have condensation included in the analyses,
but the effects of condensation on chemistry and the effects of
condensation on, you know, hydrology in the drift are not relevant, so
we\'re going to delay that discussion, too.

And the effects of natural ventilation through the rock on the thermal
hydrologic response, I think as acknowledged by Dr. Cerling yesterday,
probably have the effect of decreasing the predicted temperatures from
the temperatures that we\'re going to project. I don\'t know if that\'s
conservative or non-conservative, to be honest with you, but it has the
effect of over-predicting the temperatures, so we\'re not going to
discuss the effects of natural ventilation, natural convection on
reducing the temperature projections.

The next one, seepage chemistry, and we\'re hitting on these because,
even though seepage chemistry does not affect the deliquescence, they
are two separate issues of how the dust deliquesces or salts in the dust
deliquesce in the absence of liquid water coming in is one part of an
issue and seepage chemistry and aqueous chemistry is another part of the
issue. The Board did raise it as a question in their executive summary.
It wasn\'t in the letter itself, but it was in the executive summary. We
thought it was important to put this in a holistic context rather than
only focus on dust deliquescence, but to broaden it to the whole
evolution during the thermal period, which can include seepage
chemistry.

\"The Board believes the possibility of seepage where the rocks are
above boiling cannot be excluded, but that seepage would most likely be
limited. The DOE\'s analyses of water chemistries and their corrosive
potential are extremely complex and suffer from empirical and
theoretical weaknesses. Thus, the Board does not have a high degree of
confidence in DOE\'s conclusion that any seepage water would be dilute
or noncorrosive, because the methods used in the DOE\'s analyses have
significant technical uncertainties.\"

With respect to this particular question, Bo will first off address the
thermal aspects and thermal seepage aspects, present additional evidence
in comparison to alternative models, in this case to an NRC
representation of their test data, so using multiple lines of evidence
to evaluate the thermal hydrologic, thermal seepage evolution in the
rock.

Carl will go on and present additional information to support the
theoretical basis behind the evolution of chemistry in the rock and the
evolution of chemistry in the drift were that chemistry to come into the
drift, to provide that additional information to support the models that
have been used in the propagation of the analyses of those models that
have been used.

Finally, to put it into the context of what does this mean to corrosion,
Joe will provide additional information of the degradation
characteristics of Alloy 22 in that thermal environment with that
chemistry and the range of chemistries that are likely. The uncertainty
in those chemistries that are likely and have to be considered. Next
slide.

With respect to significance of localized corrosion, \"The Board
believes that experimental evidence is not adequate to demonstrate the
corrosive conditions which will be present only briefly. The DOE has not
established whether nitrate will inhibit localized corrosion over the
entire range of temperatures in which brines could exist. Furthermore,
based on the DOE\'s estimates, the Board believes there is ample
chloride to cause a significant amount of localized corrosion.\"

And they go in the cover letter to say, \"Crevices are widespread on the
waste packages, arising from their design as well as from contacts
between the metal and dust particles.\"

So before Joe can talk about localized corrosion, as I said several
times, we have to put it into the context of what are those
environments. So Bo and Carl will present the environments, thermal
environments, humidity environments, the seepage environments and the
chemistry environments, both during the above-boiling phase and
below-boiling phase.

Carl will discuss the amount of chloride that actually is present during
the thermal period in the rock and in the drift if it were a salt, salt
bed and deliquesced.

Then, that will be followed with Joe presenting the corrosion
information. There\'s not a lot of additional information collected
since last May on a range of corrosion potentials and critical
potentials, in a range of environments to better define where localized
corrosion is likely to be initiated and where localized corrosion is
unlikely to be initiated.

Joe will also discuss whether the relevance of dust with respect to
severe crevices and a comparison of the dust against the severe crevices
that are used within the laboratory testing program.

The Board summarized their comments in their cover letter by saying,
\"Thus, the board believes that under the conditions associated with
DOE\'s current high-temperature repository design, widespread corrosion
of the waste package is likely to be initiated during the thermal
pulse.\"

Obviously, from all the previous slides that I\'ve presented, and the
information that will be presented following me, from Carl and Bo and
Joe, the DOE will conclude that widespread corrosion of the waste
package will not occur during the thermal pulse, so we disagree,
obviously, with your conclusion.

In summary, the Board\'s, as I think has been noted several times
yesterday and again this morning, the Board\'s letter and cover letter,
executive summary and report reflected the information that were
available to the Board essentially last May. There was some additional
information presented through last summer that essentially reflected a
snapshot of available information through last May and into last summer.
There\'s a lot of additional information that has been collected, a lot
of simulation, a lot of integration of information that was maybe
difficult to present last May when the analyses and model reports upon
which the information that was to be presented were in fact not even in
draft form at that particular time.

And, there were some issues that were not explicitly presented in May
that I\'ve listed here. For example, we did not explicitly talk last May
about the effects and magnitude of drift degradation. I think there had
been previous earlier presentations to the Board prior to last May on
drift degradation effects that were preliminary analyses that have since
been revised with updated models and analysis.

We did not explicitly last May talk about thermal hydrologic response.
It was implicit in starting with the temperature time profiles and
humidity time profiles, but we did not talk about the thermal hydrologic
models, the bases of thermal hydrologic models, the validation of the
thermal hydrologic models or the uncertainty propagation of the thermal
hydrologic models last May.

Nor did we talk about the composition of the deliquescent brines. We
acknowledged that there was salt last May. We acknowledged there was
chemistry in that salt last May, but we did not explicitly talk about
what that chemistry was, what the salts were and how those salts evolved
and could deliquesce and what their likely chemical condition would be
were they to deliquesce. It\'s interesting to go back and look at the
transcript of that meeting and see there\'s a lot of lively discussion
on this particular issue towards the end of the meeting that kind of got
chopped sort of at the end of the meeting, and hopefully that won\'t
happen today. But, we never explicitly talked about the chemistry
evolution of the dust on the surface of the waste package.

And, in addition, the last bullet there, there\'s a lot of additional
information that we\'re pleased to present today to the Board to address
their specific questions but that additional information also improves
the technical bases of the entire safety analysis and entire technical
basis behind the total system performance assessment and ultimately
improve the technical bases of the safety analysis report that will be
submitted to NRC at the end of the year.

So with that I\'m going to stop and entertain any questions for me or we
can wait for the more technical presentations.

DUQUETTE: Questions from the Board? Dan Bullen?

BULLEN: Bullen, Board. Can we go to slide 2 on the left-hand screen,
please?

First, let me compliment you on a very detailed and complex TSPA that I
know you guys are putting together for the license application, but I
kind of have a question for you and we\'ll put it in the context of,
we\'ll take it out of the time frame necessary to end this fiscal year
or calendar year, and say, in the future, if some unnamed regulatory
agency should ask you, how much effort would it take to evaluate a
cooler design? What significant changes would you have to make to this
TSPA and how long would that take if you got an RAI from that
organization?

ANDREWS: Let\'s not answer the time part, but it is fair to answer what
things would change. The thermal response of the repository affects the
degradation of the rock mass around the repository. It affects the
seepage and thermal seepage analyses, it affects the chemistry evolution
in the rock mass, and in the drifts. So those aspects which would be in,
either by the way, but a technical basis document\--we had that
presentation to the Board last Fall, so technical basis documents 3, 4,
5 and 6 would be impacted and the analyses and model upon which they are
based would be impacted.

I do not believe personally any additional model validation, you know,
is required. I think the models are valid over a range of thermal
conditions. But additional analyses and calculations and designs would
be required, which would take a significant amount of time. And, just to
set the record straight, the TSPA might be complete, but it\'s not
complex. And I think we have an opportunity to talk to the Board in
September/October time frame about the TSPA and we are going to welcome
that opportunity.

BULLEN: Bullen, Board. I guess just as a follow-up to that, I\'m a
little bit confused by the fact that you didn\'t want to address time.
If the repository at some point is going to be cool and you need to
model a cool repository, how difficult is it to do that at a different
time frame in the lifetime of the repository?

ANDREWS: Well, I\'m not sure I exactly understand the question, Dan, but
how it got to cool makes a difference.

BULLEN: I understand. But if it never got to hot, is there a very large
change in the model requirements and the time necessary to do that?

ANDREWS: No, not the model\--that\'s what I said, the models are
essentially unchanged, but the analytical bases has to still be
performed. In other words, the calculations of how you think it responds
as a function of time. Because the repository will respond, you know.
There will be\--you are stressing the repository by the opening of holes
and introduction of waste that has heat, so you have to analyze that
response mechanically, thermally, hydrologically and chemically because
that affects how the repository behaves.

BULLEN: Bullen, Board. I guess the follow-up to that question is is the
analysis for a cooler repository significantly different, more
difficult, less difficult?

ANDREWS: The same.

BULLEN: Okay, thank you.

PARIZEK: Parizek, Board. Bob, I found your presentation very clear and
more or less the whole road map of how the day is going to proceed. And
for one, it would be helpful if, as each presenter gives their part of
the story, that they indicate what\'s new, what new data, because you
imply that you have done a lot of additional work, and that\'s helpful
to the Board because we\'re analyzing on the basis of what we had. If a
lot of new information is to be provided, if the speakers could sort of
remind us of what\'s new because there\'s a lot going to happen today
and it will be kind of hard to keep track of all of this.

ANDREWS: I\'m sure they will.

PARIZEK: And then I hope we will get a copy of Margaret\'s comments as
well.

ABKOWITZ: Abkowitz, Board. Bob, I was just reflecting on the EPRI
presentation yesterday and some of your opening remarks and I\'ve sort
of leafed through some of the summary positions that the remainder of
the speakers today will be talking about. And, you know, there seems to
be a very emphatic statement coming back to the Board that this is a
non-starter. And so I was curious that if the uncertainty in all of this
area has now been removed, is there any consideration that you\'ll go to
a hotter design? And if not, why not?

ANDREWS: Well, I won\'t speak for the Department on whether they\'re
considering a hotter design or not. I can tell you the bases for the
license application, which is our near-term goal and objective, is the
design that was presented to the Board in January, and the analytical
bases for that has been presented to the Board in a number of
presentations, including the ones today. So there\'s no short-term, you
know, plan to, if you will, go to a hotter design. Is there any reason
why you wouldn\'t go to a hotter design? No technical reason
necessarily. There might be some point in the temperature profile where
you don\'t want to be for other reasons, you know, design operation type
reasons, ventilation type reasons, or whatever. But I\'m trying to
analyze the design that we have and provide the bases for the
performance assessment and the barrier analyses that are required for
the safety analysis report right now.

BULLEN: Bullen, Board. Just to follow up on that one. I think there
still is a temperature limit, isn\'t there, at the clad credit? I mean
do we want to not go above 350 for the cladding so that\'s sort of the
peak repository temperature and does that not drive it or is there\--

ANDREWS: There are some design requirements of that nature for the
cladding and for the drift wall that are not performance-based design
requirements, though, right now.

BULLEN: Thank you.

DUQUETTE: Questions or comments from the audience?

None. I want to thank you for not only being on time, but being early. I
think this is the first time in this Board\'s history since I\'ve been
on it.

The next speaker is on Thermal Hydrologic Environments and Thermal
Seepage by Bo Bodvarsson, who is the Director of Earth Sciences Division
of the Lawrence Berkeley National Laboratory. Bo?

I would remind the speakers, by the way, to use the microphone as much
as possible. These microphones have very little throwing power.

BODVARSSON: Okay. Good morning and thank you for the introduction. Just
like Bob said, it\'s an honor to be here and talk about the recent Board
topic. It was clear, like Margaret said this morning, we have taken your
comments very, very seriously and her instructions to me and the others
is to do a lot of work and also show you all the new things we have done
since our last meeting. So I\'m going to try to emphasize those. If the
Chairman allows, I don\'t mind questions during the presentation at all.
It\'s up to you, to clarify things as we to along. I would actually
prefer that. It\'s up to you.

DUQUETTE: Unless it\'s really a burning question, I\'d just as soon wait
until afterwards.

BODVARSSON: Okay. Now, the outline of my talk is shown there on the
right-hand side, on the left-hand side. It\'s very, very simple. I\'m
going to talk about the capillary barrier, I\'m going to talk about the
vaporization barrier, and I\'m going to talk about in-drift thermal and
humidity conditions.

The Board had a lot of comments about all these factors in their last
letter. Like Bob said, some of it is due to the fact that we have
clarified our position with new plots, new paper, new information, and
hopefully I\'ll show you most of those today.

So, first let\'s go into the capillary barrier. These man, Yvonne Tsang
helped me prepare this talk. Jens Birkholzer and Tom Buscheck and Stefan
Finsterle of LDL have been really instrumental in the analysis of the
capillary barrier, thermal barrier and in-drift PH conditions. Next one.

So you see there on the left\--oh, can we go back on the left-hand side
there. Yeah. First, I wanted to show that we have done really extensive
testing of seepage in the repository area, and if you can click it again
you can see the other niches, in all the locations really have done
testing. So I want to really highlight that there are multiple occasions
where we have done tests and on each of these locations we have done
multiple tests of those locations. They include permeability ranges over
pore water ranging from 10 to 100 darcies down to a few millidarcies. So
we have covered a very wide range of hydrological conditions.

You will also see in the red there that we have done extensive testing
in the lower lithophysal. This was one of the misunderstandings by the
Board was that we didn\'t do seepage testing in the lower lithophysal.
We have done lots of testing in the lower lithophysal. This I\'ll
explain to you a little bit later. So I just want to impress on you that
we have done many, many tests at various locations, different
heterogeneities and different rock conditions. Next one.

So, the capillary barriers and the thermal barriers, I want to explain
these a little bit to you. On the left is a capillary barrier, on the
right is what we call vaporization barriers. These are redundant
barriers. That means they can both help us. The one on the left, this
one here, the fact is that water does not want to go into the drift. It
wants to flow around the drift as is indicated by the water and it\'s
simply because water doesn\'t like to go into big openings. This is very
well known in physics and I think the Board acknowledges this, that this
is going to happen and we have done very many tests. These are very,
very conservative because are testing basically, we put water right on
top of the niches and boreholes just about a meter from the niches, so
we are almost forcing the water to go into the niches during testing. So
the testing is very, very conservative when we calculate seepage into
the drifts.

The other barrier is also quite interesting because it occurs at a
different location. Here is where you have the thermal dry-out zone
where the rock is basically dry, where the saturation of liquid water in
the matrix is practically zero. The same in the fractures. And the water
trying to get into this zone will just simply vaporize again and move
away from the drift. So there\'s a lot of shedding and I\'ll show you
later that the saturation increases over here on top, and the fractures
are going to be very, very small because the water is just going to go
up and then shed around the niches. So almost all of the vaporized water
that forms a steam and condenses out here is shedded away between the
drifts. Well, this is a very, very powerful barrier. The temperatures
here, on the order of 120, 140 degrees and out here might be cooler, on
the order of 96 degrees or so.

The other thing I wanted to mention a little bit here also is gas
pressures in the drift here. There has been some suggestion about the
gas pressure would increase substantially in the drift. That\'s not the
case. It will only increase by 10s of 100s of Pascals. This is very,
very small, and all of our models, including the multi-scale model,
including the thermal hydrology model, they all agree with this, that
this pressure increase is going to be very, very slight, indeed.

The other thing also worth mentioning here is that the conditions in the
drift during this boiling period are going to be primarily steep.
There\'s going to be very little air there. It\'s all going to be
displaced by steam. So the mass fraction of steam here is going to be
about 95 percent or so, so very little oxygen is going to be available
there or here because it\'s all steam, because steam is generated in the
rock here and steam flows into the drift so this is full of steam. So
next slide, please.

So I\'m going to start and try to clarify some of the concerns of the
Board that they raised in their letter. First one is this one,
capillarity is a well-recognized phenomenon in unsaturated rocks. So
they acknowledge that this occurs. But DOE has not demonstrated that the
conditions required for a capillary barrier to form are satisfied
throughout the drifts. The DOE view is based on insufficient data in
modeling. And my first slide on the left-hand side there that shows you
all the data that we have collected, you kind of tend to disagree with
this. We have collected a lot of information over a wide variety of test
conditions, different permeabilities varying from four orders of
magnitude, so we think the data that we have are substantial.

Next one on the other side, please. Right side.

Well, this is again the data. So I just wanted to show you again all the
information and all the data that we\'ve collected. So now I want to go
into these slides here which is the left-hand side and go in details
responding to or trying to clarify some of the concerns from the Board.

Actually, this is not the right one, John. This is one on the thermal
seepage. Must have gotten out of order. Where\'s the one on the ambient
seepage list? Can you go\--just the\--Slide 9? Yeah, that\'s excellent.

So the Board has raised all of these issues regarding the roughness of
the drifts, mass balances, seepage thresholds and all of those, so what
I plan to do, if it\'s okay, I\'m going to go through all of those
separately as we go along.

First of all, though, we believe that the seepage data that we have
collected is very sound and actually very conservative because we put
water right above the drifts. We think that the liquid release test that
provides seepage relevant data of the right scale, they reflect all the
processes that are included, they reflect the roughness of the drifts
because all of our drifts are rough. We think the heater test data have
also corroborated the seepage results. We also believe that our modeling
approach in terms of using a the permeability model is the most
defensible way of analyzing the data from Yucca Mountain. We think there
is a great consistency between the data and the calibration, and we
think we have a proper validation as well as a proper propagation in
TSPA, because all of this data needs not only to be analyzed and
validated, but it has to be the correct level, uncertainty propagated,
all of it through TSPA.

So, the testing and models that the testing has provided data with
various degree of heterogeneity. We have looked at evaporation
potential, looked at the right boundary conditions and we have
calibrated the models. The models reflect the right geometry, the
evaporation effects, transient effects, heterogeneity, unsaturated flow,
obviously, capillary barrier effects. And then these together, we used
the models to predict storage in the rock flow diversion, around the
niches, evaporation and ultimately seepage obviously. This model takes
into account in an effective model way capillarity, roughness effect,
film flow, and then drift effects.

Okay, so let\'s address this first question there on the left-hand side,
emplacement drifts do not have a regular curvature or profile? And
that\'s absolutely correct. All of our niches are rough. All of our
niches have fractures intersecting the niches, all of our tests have
dealt with an actual in-situ conditions, so we believe that our testing
and models accurately take this into account. And we also take into
account the drift degradation effects, and their impact on seepage has
also been evaluated using the seepage models.

This will tell you a little bit about drift degradation and as Bob told
you before we are not going to spend a lot of time on this. There is a
slide in the back-up if you\'re interested in results in drift
degradation that talks about that a little bit more in terms of thermal
hydrology. A few months ago, I think about a year ago, our analysis
suggested that the drift degradation would be very large, that actually
some of the drifts would double in size due to thermal cohesion effects
and due to seismic events. This is not the case any more. I show you
here a few cases for the lower lithophysal rock and you see for most of
the rock, that the shape of the drift is going to be the most impact. In
some cases where you have very bad quality of the rock, there is some
minor drift degradation. But this is much, much less now in our AMRs
than before it was, I think it was about a year ago or so.

We actually analyzed using all of our models the case of a year ago
where we thought there would be a very, very big effect, so we included
this in the seepage model and included this in the thermal seepage
models and all of those, and like I told you there\'s one slide in the
back-up that you can look up. This actually shows the effect of drift
degradation on the thermal hydrology models.

Just to summarize for you, even if you had drift degradation, the
capillary barrier is still valid. It still holds, and there\'s no
question about it because the capillarity in the rock around the drifts,
it\'s much stronger than that in the drift. So the capillary barrier is
still valid even if you have drift degradation. The thermal barrier, the
vaporization barrier, is also still valid if you have drift degradation.
I can talk about that if you go to the slide in the back.

Let\'s take the second issue here. Surface roughness affects seepage. We
totally agree with this. Surface roughness affects seepage. It\'s fully
taken into account in our models and analysis. Like I told you before,
all the drifts are rough surfaces. They have film flow, they have
fractures intersecting them, about 50 to 100 fractures intersect the
drifts from the location of the injection interval and we believe that
these are all taken into account in our tests.

The effect of lithophysal cavities obviously are also taken into account
because we don\'t go in and remove them before we test. They are there.
They are in place. And when we do the test, their effect on the test is
shown during the seepage in those rocks. So we believe there is a very
consistent conceptual model. This is used for both the calibration and
protection and fully takes into account the roughness of the drifts.

The third aspect that needed clarification in the Board\'s letter was
the mass balance in the test. And, the Board is absolutely correct that
we have not had the test that fully accounts for all the molecules of
water that we inject in a given test. We have various parts to the test.
We inject this Qrelease, means the injection of water, and that has to
equal whatever seeps, whatever is evaporated, whatever goes into the
rock mass, into the matrix and whatever goes around the rock. We believe
the tests were of sufficient duration to assure that any potential
seepage would have occurred, and we did these tests for different time
intervals to make sure that we have steady state seepage, that normal
water would seep. And this is really the basis for why we think that we
have the mass balance that is required to have a real good foundation
for the basis of the capillary barrier tests.

We did do an attempt to actually do a fully mass balance test in Niche
No. 5 where we actually put slots around the niche. We tried to catch
the water that would be diverted around the niche so we would have a
complete mass balance. It was very difficult to construct those slots so
that test was not as successful as we hoped it would be. So right now,
the flow that is diverted around the drift is provided by the calibrated
simulation model. But the main point here is that the tests are of long
enough duration that we are getting all the seepage that we would get
for those specific conditions.

There was a comment that no seepage tests were in the lower lithophysal
unit. This again could be just a problem with our presentation in May.
We want to assure you there have been lots of tests done in this
important repository unit in the lower lithophysal. The Niche 5, we have
two boreholes there and have done a lot of long-term tests in Niche 5.
We have also done systematic testing that Yvonne Tsang has been involved
and done a bunch of tests in the ECRB, which is primarily in the lower
lithophysal rocks. So we have lots of testing that take into account the
higher fracture frequency of the lower lithophysal rock because there
are more small fractures there, as well as the lithophysal cavity
aspects of that rock. Let me just show you those tests a little bit.

This is the slot I was telling you about in Niche 5 where we tried to
get mass balance along the niche. That is the sign of the Niche 5 and
you see the slot here on the right-hand side and the left-hand side.
This is the systematic testing shown here that is done in the ECRB and
in the lower lithophysal rocks in many locations. And those are the
slots or those are the water collection pipe of systematic in the ECRB.

These are some of the testing in Niche No. 5. And this is the seepage
model that matches these tests, calibration period and we wait until it
reaches steady state until we match the data. We use a very complex
heterogeneity based on the air permeability test so we fully take into
account the heterogeneity and permeability before we start the testing.
This is included in the model right from the start.

These are the results of some of the systematic seepage testing. Here,
we calculate and measure seepage and you see the agreement is pretty
good. We also monitor relative humidity to estimate the amount of
evaporation that takes place, and then on top there is actually
injection rate. Another test. It looks like a lot of noise in the test.
There\'s not really that much noise. The reason for this is basically is
that you have a big vessel of water and you have a very small amount of
water injected and so that you get a significant, what looks like
moisture, but really doesn\'t have very much effect at all because the
average is all that counts.

So, yeah, this just shows the model validation. This shows you that we
not only matched the data, but we used uncertainty that we propagate
from the test to TSPA, so these are five percent to 95 percent
confidence interval, so you can see that with that we are very much more
conservative than the actual test results. And all of this uncertainty
analysis is propagated through TSPA.

The Board made a statement that the seepage threshold of 1,000
millimeters per year is too high. And again, this could be misleading by
my presentation or somebody\'s presentation because it was just as a
point of reference is to tell you that the seepage threshold in these
rocks are typically on the order of 1,000 millimeters per year. But the
fact of the matter is, we don\'t use a single number because it depends
on three major factors what the seepage threshold is, when it seeps and
when it doesn\'t seep, and that is simply given by this diagram here
which is used extensively in TSPA. This diagram says that the seepage
percentage is a function of the permeability of the rock, is a function
of the capillarity of the rock, and is a function of the percolation
flux, which means how much water is flowing through that rock.
Obviously, the higher the percolation flux, the more seepage you\'re
going to get.

The higher the permeability, though, the less seepage you\'re going to
get because more water will flow around the niche. Less water will flow
into the niche, so it\'s inversely proportional to permeability so you
see lower values here and you see more blue color here.

Obviously, the lower the capillarity of the fracture system, that means
the ability of the fractures to hold onto the water molecules, the more
seeps. So basically, TSPA uses all of this so there\'s no single seepage
threshold. If you have one location where the permeability is small,
let\'s say a millidarcie, where the capillarity of the fractures is low,
say 200 Pascals to 400 Pascals, and the percolation flux is high, we may
have a threshold of 100 millimeters per year or 10 millimeters per year
or much, much less. Conversely, in areas of low percolation flux, high
permeability and high capillarity, you will have a much higher seepage.

I just wanted to give you some results from the seepage and to show you
the amount of uncertainty that is propagated to TSPA or the actual graph
here. You have the percentage of percolation flux that seeps. For the
ambient case\--this is only for the ambient case\--and you\'ll see here
with the current climate you have something like one and a half
percentage seeps. For the monsoon, you have higher seepage, for the
glacial transition, the mean is something like eight. You see the huge
effect of the climate predictions and obviously it\'s because we don\'t
feel that we can accurately predict climate over the next 10,000 years
so we have to have a wide viability in our seepage results. So TSPA will
sample all the way from 1-1/2 percent all the way to 10-15 percent or
higher how the percolation flux will seep, so it\'s a lot of variety, a
lot of uncertainty in climate.

Now, the amount of water that the waste package will see if it actually
seeps is given here, and it shows here, it\'s like two liters or so,
goes up to 20 liters, goes up the mean like 30, 40 liters. And again,
you have a wide range of values due to uncertainty in climate.

And, I want to emphasize here, these are ambient results. When we
superimpose on these the thermal effects, you will see there is no
seepage during the first 600 years or so, in general, for most of the
waste packages because most of the drifts will be above boiling. And we
believe, I hope to show you data and information that will show you that
if the drift wall is above boiling you will not see any seepage. So
these are simply ambient things, that TSPA then looks at the temperature
on the drift wall and say if it\'s above boiling, let me put that to
zero. That\'s how it\'s handled with the TSPA. Is that clear to
everybody?

Let\'s go to the next one here.

Film flow in the operation. Again, we agree with the Board; there\'s
going be to film flow, there\'s going to be evaporation. This happens to
be the wall in Niche 5 where you actually see film flow on the walls.
This is taken into account in our seepage testing and study because if
it doesn\'t go into our collection system, it\'s not seepage. It flows
around the drifts. In addition to this, as you probably have heard many
times, John Stuckless have used natural analogues in tunnels in Egypt
for example, which have paintings on the tunnel walls that show that for
many, many thousands of years you have had no seepage in these tunnels
because otherwise the paint would be gone. So we use actually lots of
analogue to kind of corroborate what our testing does.

Our active fracture model, there was a comment that the active fracture
model has not been fully validated. Really, the active fracture model is
used heavily by the project. It\'s most important for transport, it\'s
not that important for seepage, so it really doesn\'t apply very much to
seepage. It doesn\'t rely on the active fracture model. Of course, in
TSPA for predictions of the future we use full focusing that depends to
some extent on how many of the active fractures actually flow. The
active fracture model is very important for transport, and the
uncertainty in this parameter, again, just like the climate uncertainty
is propagated to TSPA.

Another comment, persistence of the capillary barrier continues along
the drift is a question, and again, I think this is a very good comment.
If you don\'t test every location in every drift, how do you know that
you\'re going to have a capillary barrier everywhere. Obviously, you
can\'t test every drift in every location and every drift. But I have to
say again and emphasize again, we have tested our orders of magnitude
amounting to its permeabilities, we have tested our orders of magnitude
in percolation flux or input of water. We think the testing phase is
sound and we think we can extrapolate that testing phase with the proper
uncertainty propagation to TSPA for ambient seepage.

The other thing I wanted to point out is the ECRB test where we have
actually left the bolt cap closed for years now. I think it\'s about
three years or so. And there, that\'s kilometer of rock. All the
heterogeneity that you\'re going to see in the lower lithophysal and we
have seen no seepage, which is consistent with the models that we have
developed for the lower lithophysal rocks. So to me that\'s a very
long-term test that should at least give us some confidence that the
capillary barriers is persistent over all the drifts.

Now, I want to move on to the thermal barrier. I\'ve finished all the
comments about the capillary barrier. I want to talk a little bit more
about the thermal barrier.

The thermal barrier is, as I mentioned before, a redundant barrier. The
capillary barrier does not go away if you have a thermal barrier. So
even if water, small amount of water, would get to the drifts, the
capillary barrier will help it move along the drift, just like it did in
the ambient case. But the location of the thermal barrier is much
further away. The boiling, or the dry-out zone is some five, six meters
away from the drift. That\'s where the thermal barrier is, primarily.

I want to explain a little bit about, a little bit more because this
needs to be a little bit clear, the physics of what occurs here. When
you boil this water, the temperature from the boiling front moves out
with time. Steam is generated, steam moves out radially and condenses in
the outer region, all around the drifts. Not only above, but all around
the drifts. The saturation in the fracture increases from an average of
three percent to about six percent. So there\'s no leak or anything up
there for these sites here or anywhere. There is a tiny amount of
increase in saturation. Why is that? It\'s because the rock in general
is so permeable it\'s basically the hardest permeability is a darcy to
about 10 darcies, so 10 to the minus\--11 to 10 to the minus 12 meters
squared. That means any increase in saturation that I see here causes
water to do one of two things. It\'s not going to flow up, it\'s going
to flow either sideways or down. If it flows down, it\'s going to
vaporize again. If it flows sideways, it\'s going to shift. So most of
it is going to shift. The only important thing here then is the
chemistry of the water. We talked about this yesterday. I made a comment
yesterday, if the water here is always refreshed, in quote marks, and
you condense steam, because, closed quote, the old water has already
shedded, then chemical concentration in this water is going to be
extremely benign because condensed water is pure water without
chemicals. It has to have time to sit there in the rock and pick up the
minerals in the salts.

So that\'s a long introduction of whatever us young guys do, talk a lot.
I\'m the first of the young guys, then two more.

So the general statement is this: \"DOE has not demonstrated, is the
conditions required for pervasive vaporization barrier to form will
occur everywhere. The DOE\'s view is based on insufficient analysis.
Future testing under in-situ conditions in Yucca Mountain may improve
technical defensibility or any claim about the effectiveness or lack of
effectiveness of a vaporization barrier. We certainly agree any
additional data will help us, but we think we have the necessary basis
to go through our license application with a solid case for a
vaporization barrier\", and let me tell you why.

So if you can put the next one here and the next one over there. That
one should be on the left-hand side. The thermal barrier, the one you
asked me for.

(Pause.)

Again, we want to talk about testing. First, what are the data we have
available for thermal, and I want to emphasize once more that the
vaporization barrier depends on the capillary barrier, so all of the
capillary tests that we have done with the capillary barrier helped us
with the thermal barrier because they are redundant barriers. In
addition to that, we have had the single heater test, the long block
test and the drift scale test. Very long-term testing. Drift scale test
is the biggest test ever conducted in the world, I believe, and is a
very important test for us. I think all of us, all of these tests will
help us validate the vaporization barrier. We have also done a
tremendous amount of modeling to help us understand this important
barrier for us.

First of all the conceptual model has been validated against seepage
test data and thermal test data so I want to start by telling you a
little bit about the thermal test data we have.

The drift scale test has provided a tremendous amount of data that helps
us validate not only the thermal hydrologic models, but also Carl will
use it to validate all of the chemical models that we have, the THC
models, as well as the thermal mechanical models. It has really helped
us understand these processes.

This just happens to be some temperature profiles that we used to get
confidence in our model. Next slide, please. This happens to be air
permeability data that we do in many, many boreholes to give us
confidence that we appropriately represent the thermal mechanical
effects as well as saturation changes in the rock mass.

We had also done a lot of geophysical data to verify the existence of
the dry-out zone. This happens to be Electric Resistance Tomography
data. You can see it shows a similar dry-out zone. We also have Ground
Penetrating Radar that shows very similar things.

Also collected water in boreholes. And the water in boreholes has been
extremely useful for us to look at the chemistry and how minerals are
picked up on the rock, just like I mentioned before. Takes a while for
it to pick up the minerals in the rocks. We see the model\--this is
saturation plots for a borehole and you see that we get water into the
borehole when its activation is the highest, which is consistent with
our models. And then the same thing here. You get water in the boreholes
so the models are consistent with when we get water in the boreholes.
You don\'t always get water in the boreholes. You only get it at these
great intervals when the condensation shown has moved to that location.

So I believe, or I think we believe jointly, that the data in the drift
scale test has given us tremendous confidence in our ability to model
the thermal hydrology, and like Carl will talk about a little bit later,
the chemistry as well as the thermal mechanical effect. All of these
effects are\--so we think we have adequate basis for licensing,
certainly for the vaporization barrier. Any additional tests are, of
course, going to help us verify these concepts. Next one here, please.

This just shows us, we talked about not having a thermal test in the
lower lithophysal. I just wanted to emphasize that the drift scale test
actually includes the upper lithophysal rock even though most of the
tests is in the middle or left. The boiling condensation processes
extend into the upper lithophysal rocks so we have some testing in the
lithophysal rocks. A lot of the boreholes are located in the upper
lithophysal. So it\'s not strictly correct to say that there has been no
testing on thermal behavior of the lithophysal rocks, because that helps
us a little bit. Of course, it would help us more to have a whole test
in the lithophysal. There\'s no question about that. Next one, please.

Yeah, so this basically talks about the same thing. The reason we also
believe that our results from the drift scale tests are applicable to
the lower lithophysal are explained pretty much in this slide here. The
primary thing that changes the response in our heater test is the
thermal properties of the rock. It\'s not the hydrological properties of
the rock. It\'s not the lithophysal cavities, per se. It\'s the thermal
properties, primarily thermal conductivity. And why is that? 90 to 95
percent of the heat transfer in the drift scale is rear conduction.
It\'s conduction dominated, and therefore the primary response you get
if you go into the lithophysal is changes in heat capacity thermal
conductivity. All of those are fully taken into account in our thermal
models. We have accurate measurements of heat capacities and thermal
conductivities which I\'ll explain a little bit later, and they are
applied to the right units, therefore we think that the process
understanding we have obtained through the drift scale test is
applicable to any of them.

There has been issues with the leaky bulkhead. And, of course, it would
have been really nice to have a fully closed bulkhead, no leakage
whatsoever. That is not practical, of course, because steam is a gas.
It\'s very hard to confine it in a permeable rock. It\'s very hard to
put a totally sealed bulkhead in there. We have taken this into account
fully in our models and this is a paper by Summitt (phonetic) and Yvonne
that was published in General Contaminant Hydrology that has analyzed
the leaky bulkhead. They conclude that less than 30 percent of the heat
and energy is used to convert water into steam. Most of it is conductio,
as I told you before. It would have increased the fracture
permeabilities, fracture saturation some, had the bulkhead not been
leaky, so we have taken into account both the cases with the leaky
bulkhead and without the leaky bulkhead, and all of our data so far
confirms the model prediction for a drift scale test when we allow the
proper leakage to occur in the system. So we have taken this into
account in our analysis. Next one, please.

The validation of the seepage threshold, thermal seepage model has been
done by using ambient seepage, and also the drift scale test as we
talked about before. Next one, please.

Here are some of the results of the ambient seepage model. We are
comparing it now to the ambient seepage. This was the ambient seepage of
12 percent for 120 millimeters per year, which was very, very high
percolation flux. It goes up to 22 percent for 320 millimeters per year
up to the climate change and then further up later on. We get no seepage
obviously until boiling ends, then we get the gradual increase in
seepage. This is again considerably less than the ambient seepage, but
you still get seepage after the wall of the drift has gone below
boiling. We do, however, conservatively reflect this benefit. We don\'t
take it into account at all. After boiling ceases at the drift wall, we
assume fully ambient seepage. No further benefit of thermal effects. So
we are conservative in the analysis of this for TSPA. However, we think
we have the basis to say there\'s no seepage during the boiling period
when the temperature in the rock is above boiling. Next one, please.

This is some of the results of the model. Again, I told you the shedding
of the water above here is very important. The dry-out zone is very
important. And you see the different colors due to the heterogeneity of
the rock. Permeability in this model there is about four inches of
magnitude or so, generally to about 100 darcy or about 10 millidarcies.

The other thing I want to emphasize again, the fracture saturation here
even though this looks big, the numbers are very, very small. It goes to
about six percent or so, the highest saturation, so still most of the
fractures contain 94 percent air. Only six percent contain water. Next
one.

Again, to emphasize this point, and I\'m sorry I\'m emphasizing it so
much, but all this here talks about leaks above the drifts and lots of
water. There\'s almost no water there. And, we did a little exercise
where we just integrate the water in the condensation zone, so we don\'t
take into account the dry-out zone. We just look at the saturations in
the fractures and in the matrix where the condensation zone is. Okay?
And this is the fractures with time, this is the matrix with time. And,
you see these numbers are tiny. The total amount of increased water
above the drift there is .25 liters. .25 liters. .25 kilograms is almost
none. So there\'s no water to come back and reflux. It goes and
sheds\--permeability of the rock.

So this is very important. The total amount of water that imbibes into
the rock is only about a liter in they integrated zone over time. Why
does it go up here?

Climate change. 600 years. Why does it go up here? Climate change of
2,000 years. Next one.

Geothermal analogs have also given us confidence in this model because
the same processes have been used to model geothermal for 20 years or so
with the same family of codes. And let me give you an example of
geothermal because I think it\'s important. Some geothermal systems are
vapor-dominated systems. That means the pressure profile in them is
vapor static. It\'s not liquid static, it\'s vapor static. The pressure
doesn\'t change. It\'s almost like Yucca Mountain, a uniform pressure,
often at 35 bars for some reason. Yucca Mountain of course is one bar.
The injection of liquid water into those systems to enhance the systems
and increase the lifetime of the system is very important. Water is
injected at 20 degrees centigrade; cold, cold, cold water. Temperature
in-situ is 240 degrees, similar to what we have here. The waters are
producing lots of steam, the steam turns turbine, makes money. Cold
water moves in the reservoir, similar to what it does here and tries to
go to the production wells. But it can\'t get there. Why? Because it
does the same thing it\'s going to do with Yucca Mountain. It vaporizes.
So you see in the isotope signature of the water that is produced, that
100 percent of the water produced is injected cold water that vaporizes.
So even if the driving force it shoots because you\'re producing steam,
you\'re attracting the water to you which is totally different than
Yucca Mountain, the drift does not want the water. The production well
and the fuel from the reservoir wants the water because it\'s producing
steam. Pressure gradient storage. But still the vaporization is very
important. So this gives us confidence in our vaporization barrier. Next
slide.

Now, real quick, the NRC experiment, many people point to the NRC
experiment saying, well, it seeped there. Why did it seep there? Is that
consistent with DOE models? The bottom line here, it\'s consistent with
DOE models. We did this exercise just recently, at Margaret\'s request,
just to show you this. This is the experiment by NRC, they are concrete
slabs of those dimensions, five centimeters by five centimeters, and
then they are real long. They are about 60 centimeters. This is the
boreholes, you see about three fractures intercept the boreholes. You
make the most conservative assumption that you can possibly make, you
put water right about here and let the water go straight down. The
seepage in here was never visually observed or at least I\'ve seen no
literature that says that seepage was actually observed. But there was
some precipitates found in there. So we assume that seepage occurred.
The experiment was basically 130 days. Lots of water put here. This is
the heater output, etcetera, etcetera. Next one.

I don\'t know the details of this experiment not a heck of a lot. Next
one.

The comparison matters though. Here is the NRC, this is Yucca Mountain.
We have tuffs, they have concrete slabs which are a little less
permeable. The fractures are all continuous there. We don\'t have that
case here. Your diameters are different. Three fractures hit the drift.
We have 50 to 100 fractures that actually hit difficult drift at Yucca
Mountain. These are the fluxes, about 100 times more than what you have
at Yucca Mountain. Heat outputs, temperatures comparative. Next slide.

So we did this model, basically took one-fourth due to symmetry. That\'s
a detail you don\'t need to know, I don\'t know a lot about. Next one,
please.

This is what we get. We get heat pipes that were observed. We saw three
sensors. You see them here along, above the heater. Boreholes, they show
heat pipe conditions. And next one please.

You can see after 140 days there is heat pipe pretty much everywhere.
The saturation has increased close to the drift. There is higher
saturations close to the drift, and for cases, for some of the cases we
got seepage into the drifts when the capillarity of the fractures is
low. When the capillarity of the fractures higher, we don\'t get seepage
into the drift. This shows there\'s water present everywhere. In the
TSPA model for seepage, thermal seepage, we would assume full seepage
for this case in our TSPA model to be conservative.

So, with respect to that, I conclude that the models that we have is
consistent with NRC data. I conclude that the models we have are
consistent with all the data we have. And Dan mentioned the large block
test yesterday as an evidence for the thermal seepage model not to be
valid. I actually think that that data shows that the thermal seepage
model is valid because it did exactly what we expected. There was a huge
rain storm with a huge amount of water going into a super heated region
and what does it do? It does exactly like the other does. It all becomes
heat pipe-dominated. So the amount of water that you got there is a
large amount of water that all of a sudden went into the test bed, and
our model results which are actually in a paper that has been published
by Water Resources Research, shows it\'s very consistent with older
models we have there. You\'re not going to get a rain storm in the
middle of Topopah Springs. So I think it\'s all consistent with the
Topopah Springs. Next slide.

So this just summarizes the test, high permeability fractures, all of
those. These are conduct details you can just have in your material.

So we conclude the NRC test is consistent in our model. I\'ve told you
this before so I\'m very briefly going to go over this. We did one more
thing to try to validate our model, even and it was a very, very
conservative single fracture that goes straight into our drift model.
Alternative conceptual model, again, has been published in a refereed
journal, by Jens Birkholzer. Next one, please.

Single fracture episodic flow, because the only issue we haven\'t
addressed is episodic flow. We have assumed so far everything is pretty
much there to stay except for the NRC experiment and the large block
test experiment. They are both transients. Episodic flow, we do this
very conservatively. We put the pulse of water all of a sudden on there
and we see, can it get through this zone? What will it take for it to
get through this zone? If it gets through the zone, how much will the
capillary barrier help us? That\'s the primary issue with this. The
basis is an experimental vapor collected by Grace Su. We did exactly
this but were on ambient system. She did an experiment in unsaturated
fractured rocks which is very, very interesting. By putting a constant
flow of water on top of a fracture, because of the heterogeneity of the
fracture, you get episodic flow in the fractures. Water moves down and
then builds up where the fracture aquifers become small, reaches a
critical head and then moves through. It shoots through. Episodic flow
in a fracture under unsettling conditions.

What is really interesting about that experiment, too, is what happens
when you increase the flux. When you increase that flux you don\'t
change the amount of heat that goes up before it goes through. That\'s
constant. So the volume of water that is needed to break through or
given out at your restriction, if you will, is a constant. So the only
thing that happened was, the frequency increased, so you just got this
break-through quicker, and it scaled perfectly over large range of
voltage, so it\'s very, very important. Jens used that paper and that
volume of water, based upon our permeabilities and fracture
distribution, he used that as the episodic flow. So when you increase
the rate you increase the frequency of these things coming down, prior
to breakthrough of this barrier. Next one.

Now this is as conservative as you can get. It must be because you have
this one fracture through there. Then he plots up the actual flux in the
dry-out zone that is trying to go through the dry-out zone, which is
very large flux trying to go through the dry-out zone, and then he
calculates the amount of flux that this should be pointing here. That is
up to this prong. This is the flux after this prong. When the
temperature, with a long, long time after emplacement, these both agree,
but you see that for a short time nothing comes through at all. There\'s
no water there, but when it starts to cool down, it becomes the same as
ambient. Even in this case here, it probably wouldn\'t seep because the
flow rates are less than the seepage threshold collectors. So again, let
me emphasize, we done the barrier, vaporization barrier, if it gets
through the crown, it\'s\--

Now, I\'m going to spend a little time about temperature and humidity in
the drifts. And, this is my last topic. This is Tom Buschek\'s work at
Livermore. The Board questions the DOE view that temperature and
relatively humidity is adequately or conservatively modeled. They think
there are significant parametric and conceptual uncertainties during the
period after the repository is closed, and I think the three primary
ones are flow along the drift, thermal conductivities, and there\'s one
more. What was the other one? What was the third one? Yeah, drift
degradation.

So I think all of you know the Multiscale Model that Tom has been
working for quite many years. The real importance of this model is the
following. Most important things are not the thermal conductivity value
or any other values. Most important thing is he fully takes into account
the mountain scale cooling. The mountain scale cooling is really, really
important here because you have three-dimensional cooling effect so
these drifts in this area are going to be the hottest. These will be
cooler because they are closest to the edges. That\'s how he breaks down
his system into different units, lithophysal and non-lithophysal with
the proper properties and then he takes into account the cooling
effects.

I\'m almost done. Next one, please? Yeah. I\'ll be on time.

He has validated his model, again using the drift scale test. This is
temperatures and this is neutral rocks that show the dry-out. Next one.

He has also validated it against other numerical models that are more
simple that use a line source. Next one. So we believe that the model is
fully validated. Then he generates temperature at the waste package, at
the drift crown, everywhere in the system for all the drifts. Different
location, different cooling, different X-effects, and shouldn\'t be in
thermal conductivities and all the parameters is propagated through TSPA
and sampled in a proper way. Most important parameters for Tom\'s model
are A, the location because of X-affects, B, thermal conductivities and
thermal properties just like we talked about in terms of testing; three,
percolation flux or infiltration. He has done many sensitivity studies
of those and I\'ll show you a couple of those.

So this just shows the cooler and hotter packages. Like I said, he has
done sensitivity studies of all these parameters. So this is a movie he
did, and it has come to a nice movie. If you can start it, it shows you
how the things cool down and the hot red is when it\'s boiling, and then
the green indicates when you go below boiling. So you can see how
important the X-affects are and you can see the time on top here, 700,
that\'s 750. This is what you have boiling now, and off he goes. After
about 1,000 years or so, after about 1100, 1200 years, there\'s no more
boiling of the drift at this location, at this time. 1200 years there\'s
no thermal seepage barrier anywhere in the system.

CHRISTENSEN: Christensen, Board. Does that assume that the thermal
output from the canisters is uniform?

BODVARSSON: No, This has different outputs from different packages.

CHRISTENSEN: Okay, so I just was wondering if the variation that we\'re
looking at, sort of the spatial variation in the drift or is it\--

BODVARSSON: This spatial variation assumes average outputs from the
packages.

CHRISTENSEN: Okay, that\'s what I wondered.

BODVARSSON: Yeah, yeah. Your question is well taken because, really,
this behavior is not going to change even if you have the right
assemblages of packages because this is really average behavior. Good
question.

This just shows the effect of infiltration. It has low infiltration,
mean infiltration, and upper infiltration, and it shows pretty much it
doesn\'t affect vastly the temperatures as expected, but significantly
more the relative humidities.

Now a little bit more about thermal conductivities. Thermal
conductivity, like I said, is the second most important parameter for
this model. The other one being are they close to the edge or close to
the center on all of this? We believe that we have very good
measurements of thermal conductivity for these models, for the following
reasons: These models do not depend on a local thermal conductivity.
What really dominates the response, all these models are the large scale
heterogeneities, so if you have localized 50 percent lithophysal
porosity versus 10 percent, which is 20 percent over the scale of 10
meters, that doesn\'t really affect things very much because the
long-term effect is integrated over cubic meters of volume of rock,
large volume of rocks. The project has done extensive testing over the
last two to three years, realizing that we can\'t measure them within
conductivities of flux and put in place heaters to measure large scale
thermal conductivities because of the lithophysal rocks, lithophysal
voids because also you recognize they are very important that during the
large scale heaters and measuring over large time frame, you know, the
large volume of rocks, we believe our basis for our thermal conductivity
values is very solid, especially with the recent data that we obtained.

So that\'s kind of all I wanted to say about that, so we have recent
data on this. Next one.

This shows just your variability with respect to thermal conductivities
and you see, you take a mean value, and mean value now is different for
all lithophysal because the lithophysal rocks is different from the
mineral non-lithophysal, but it\'s a mean for all of these units. And
then we change the mean by one standard deviation up and down. So you
see the effect is not very large, really, even though it we changed it
quite a lot so I think the thermal conductivity has not been really a
big issue here. That\'s my personal opinion. Next one.

So, finally, sorry how long this took, but Bob kept adding slides
and\--and I started at with three

slides\--one said capillary value is good, thermal barrier is good,
relative humidity is okay. And they added all these other slides.

But to summarize, what I\'m trying to tell you here is that maybe we
haven\'t been as clear in our presentation regarding the capillary
barrier and vaporization barrier as we should have been, Hopefully this
is a little clearer now. Hopefully, you understand, we have done a lot
of work since your letter came out and market has told me personally and
all of us to take this very seriously. We want to respond to this. We
have done more measurements on thermal parameters, we have done more
modeling on NRC studies, more sensitivities of the thermal barrier,
trying to solidify our case in all these areas. We have done much more
sensitivity studies. Tom Bushek has done a little more on the in-drift
environment and humidities and temperatures.

Our results and conclusions continue to be the same. We believe that the
capillary barrier is sound, that we have lots of paper to help us
validate and verify it. We have sufficient data in terms of
heterogeneity to be able to extrapolate it over emplacement drifts. Now
performance confirmation of course is going to help us with this, as all
of us know. We believe that during boiling, that the\--there\'s no
seepage into the emplacement drifts, that only if you have a huge fault,
with huge amounts of water going through the fault, could you break
through the vaporization barrier. All of our sensitivity studies and
tests point in this direction, as does the large block test, as does the
NRC test that we have validated and modeled. We conservatively use
ambient seepage when we go below boiling around the drifts. We account
for any evaporation, which is going to continue, obviously. It\'s a
continuous trend. There\'s going to be huge evaporations due to the
temperature output from the waste packages after the drifts have gone
below boiling. We neglected, we are conservative, we are surely to be
ambient. We believe that temperature or relative humidity viability is
realistically represented in TSPA, with all the uncertainties regarding
thermal properties, locations, infiltration rates, etcetera. And we
believe that, using modification in thermal properties, we can
extrapolate the drifts scale test results through the lower lithophysal
walls. And that\'s it. So, whenever you have a question let me know.
Thank you.

DUQUETTE: Thank you. Mark.

LATANISION: Latanision, Board. Could we put up Slides 36 and 46? I\'m
very interested in the concept that seepage or condensed water above the
drift will be mostly diverted sideways, and I\'m trying to understand
physically why that is the case and what the calculus\--I don\'t know
that you can make, that it\'s appropriate for me to make the comment
that what I\'m thinking of is something of an episodic event but
nevertheless that illustration includes the kind of calculus that I
think is important. In other words, you\'ve got a\--if you have a
fracture in the rock, and obviously you do, above the drift, and you\'ve
got water evaporation to the sides, as you show here, what is the
calculus that would lead you to conclude that you would not get water
emerging into the drift? Is it\--I mean am I understanding this
properly? It\'s all going to be diverted sideways rather than\--

BOVARDSSON: Yeah.

LATANISION: And the probability of getting water into the drift is
therefore close to zero, or is it zero?

BOVARDSSON: Yeah, it\'s very, very low. I think it\'s better to explain
it with this slide rather than that slide.

LATANISION: Okay.

BOVARDSSON: Because this slide really is a very, very conservative model
that doesn\'t allow you to shed water. Let me try to explain it again
here. The key to it all is that the rock mass at Yucca Mountain is
heavily broken up by fractures. The average fracture spacing is some 20
to 30 centimeters. They are all over the place. They are all directions.
You have the dominant vertical, you also have the dominant horizontal
fractures. So the permeability in any direction is pretty large. So
water can go just every direction it wants to go. Obviously, water
doesn\'t want to go up because of gravity. It wants to go down because
of gravity. But then it can also go sideways if there\'s a buildup in
saturation in the fractures, or there\'s more water there and then the
permeability increases there and allows it to go sideways. So if you
take a typical location here, up here the compensate here is due to
steam that moved up and condensed there. And it increased the saturation
there from three percent to six percent. Very low amount, but it\'s
sufficient in terms of permeability. If you do that, the relative
permeability to a liquid phase, because most of it is air, will go up by
a lot, by many times. We\'ll still have small increase in saturation
because when you have ceiling water you have no permeability to water
because there\'s no water phase, continues there. When you have three
percent water saturation you have really no permeability because the
surface area of the flow in a fracture is mostly air, really. So you
have minimal permeability, so increasing that a little bit increases the
permeability by a lot. So, the water then, somewhere it will start to go
down, try to go down, plus the lithophysals. What goes down goes now
into a hot region, re-boils and goes back up. But the top phase,
sideways, we always let it shed. It\'s gone. You see what I\'m saying?

LATANISION: Yeah.

BOVARDSSON: Did I explain that well?

LATANISION: Yeah. I mean I suppose then that the follow-up\--Latanision,
Board. The follow-up question would be are you confident enough to
suggest that a drip shield is not a necessary part of the structure, of
the emplacement?

BOVARDSSON: Well, I don\'t think I\'m the right person to answer that
question. The drip shield\--I just don\'t think I\--I think that
question should be for Joe or somebody that knows more than I do.

LATANISION: All right, then I\'ll take that challenge and ask it again.
I mean I think as a taxpayer there\'s an issue there. And therefore
funds involved in this research. Right. Whatever. I mean the fact
remains there\'s a cost involved in terms of the drip shield and if
you\'re as confident as you seem to be, I think that question is one
I\'d like to have answered somewhere along the line.

BOVARDSSON: Yeah, and it\'s a good question. I mean of course the drip
shield may be also held with rock for a little bit, and after the
thermal period then you have seepage and a drip shield is still intact.
That will help you not get any water on the waste packages so after the
thousand years or 500 years, depending on the allocation, the drip
shield kicks in, you get ambient seepage and it\'s going to help you.

DUQUETTE: Dan?

BULLEN: Bullen, Board. The first slide I would like to take a look at is
actually slide 37. And that\'s a follow-on to this question about the
slide on the left here. You said there\'s no rain storms in the Topopah
Springs, Yucca Mountain horizon. What does it take to get a rain storm
necessary to overcome the vaporization barrier? Have you done the
calculation? How many liters per whatever? Whatever your infiltration
rate might be.

BOVARDSSON: I believe we have. I just don\'t recall the number. That\'s
a good question. Most of this study, like I explained, Dan, we used the
Grace Su experiment for the right aquifer distribution to decide on a
value. Then we used that and increased that flux. But I think we did one
where we really put lots of water in and it continues to try to get it
through, but I don\'t remember how much it was of water. Sorry about
that.

BULLEN: Bullen, Board. I guess just a follow-on, is when you do that
calculation or take a look at those numbers, to be able to compare to
when the infiltration rate may or may not be there, I mean you may prove
that even in a super pluvial condition, you\'d never have enough water
in-flux to overcome the vaporization barrier. I mean those kinds of
things would be important to know if you wanted to make that case. I
mean the argument may be, well, maybe the climate changes tomorrow and
then would the vaporization barriers still work, and if you have the
answer and it\'s yes, then that would be good to know.

BOVARDSSON: Yeah. I think the answer to that, within the changes in
climate that we\'re assuming here, assuming that it doesn\'t go 10 times
more than what we assume, it\'s going to hold. The vaporization barrier
will hold. Well, the difference is is the following: If there is a huge
amount of water, the distance that we need for a dry-out zone may change
from 10 centimeters to 30 centimeters if you put a lot of water. See
what I\'m saying? But we conservatively assume in TSPA that actually the
vaporization barrier breaks down at 100 degrees, not 96 degrees. So we
were even conservative there. We\'re closer to what the NRC had
yesterday. I think they have 105 degrees.

BULLEN: Bullen, Board. Could we go to slide 4 then? This is just a
follow-on question to your comment about the fact that near the drift or
near the waste package in a vaporization barrier condition, there would
be mostly steam?

BOVARDSSON: Yeah.

BULLEN: Are there data from the drift scale test that tell me what the
partial pressure of oxygen was near that to basically I guess prove that
point?

BOVARDSSON: I don\'t recall those data, sir. I remember there were some
measurements of it, but I don\'t recall.

BULLEN: I actually have a\--Bullen, Board. I have actually a better
memory than you both because I\'ve asked that question of Bill Boyle in
1998, 1999 and 2000, and in all cases it was the partial pressure of
oxygen was the same as it is in ambient air. So there never really was
super-saturation of steam just because\--now it may have been because of
a leaky bulkhead, it may have been because of mountain breeze, but I
don\'t think you can make the statement because based on your modeling
without the data that\'s there from the drift scale test that says
there\'s going to be mostly steam. I mean if there\'s going to be mostly
steam, then we would go back to the corrosion allowance outer barrier,
which is what we abandoned because we didn\'t think that it would work.
So, that kind of statement is something that\'s a little bit concerning.

BOVARDSSON: Yeah.

BULLEN: But you don\'t have to answer anything else.

The other question I had was with respect to the\--

BOVARDSSON: Just one comment,

BULLEN: Oh, go ahead. That\'s fine.

BOVARDSSON: I think your point is really well-taken. And because you are
going to have, in the direction of the drift, you\'re going to have
diffusive component, the dispersion that tries to equilibrate, if you
will, concentration gradients, so that most of our models are
two-dimensional models and don\'t take that into account so I think your
point is well-taken. However\--

BULLEN: Sure.

BOVARDSSON: One more. We actually have done models that have taken that
into account and we find that in those models that it\'s mostly steam,
too. I don\'t remember if it\'s 90 percent or so, but it\'s still mostly
steam. But, your point about the drift scale test I need to look at.
You\'re right. Absolutely.

BULLEN: Bullen, Board. The last drift scale question, and that is there
was a brown spot that was noticed on one of the surrogate waste
packages. Was that ever explained as rock bolt dripping, or what was the
explanation for the discoloration on the waste package that was noted,
and has that been explained?

BOVARDSSON: I think it has, but who can explain it better than I can?

BULLEN: We have any members? Mark, do you remember an explanation for
that? Or Bill?  Well, come up to the microphone, please. Yeah.

PETERS: Mark Peters, Special Laboratory. The question was on the
Canister 304, there\'s a red spot back there?

BULLEN: Correct.

PETERS: It was sampled remotely, off the robot, swiped with a swab,
brought out, and it was XRD and it was iron oxide. Hematite. It\'s
currently thought, one likely thinks it could be that it was flaking off
of some of the ground support in the crown, but we really have to go in
and look after the test is over to get a much better idea of what we\'re
looking at. It\'s not clear to us that it\'s evidence of any kind of
discreet flow in the drift.

BULLEN: You said flaking? I did get the word? Flaking?

PETERS: Yeah. Well, I used that word. That\'s my word, but it is iron
oxide that gathered on Canister 3

or 4.

BULLEN: Thank you.

CHRISTENSEN: Christensen, Board. Bo, one of your points I think directly
related to Mark\'s final comment yesterday and relevant to the
discussion by the Nevada contingent yesterday, and that is the effect of
refluxing on potential concentration of salts. And, so I want to ask
really two questions. Do we have empirical data on water chemistry that,
I imagine we\'ll see later today.

BOVARDSSON: Yeah. Yeah.

CHRISTENSEN: That\'s really important. But the second\--and it may make
the second question somewhat irrelevant, but it seems to me that the
difference in view of your\--has to do with the, with the physical, what
has happened physically with the water as it\'s evaporated out, and it
seems to me that the Nevada\--I\'m not going to put words in their
mouth, but maybe looking at the convective circulation of water at the
boiling front, so they are looking back into the rock, the\--and I\'m
trying to understand why these two different views are so different.
What the potential physical explanation might be.

BOVARDSSON: Yes, sir. Good question. Let me try to explain it. Let me
explain it this way: What happens\--what we believe is happening at
Yucca Mountain and then I\'ll talk about what I think they believe is
happening. What we believe is happening is that we start by putting a
waste package in place here, we start heating up this area. You have a
boiling zone that moves with time outward. It starts next to here.
That\'s where the matrix starts to boil, steam moves out, and in 100
years or so it\'s out a few meters, and then a few meters more. Maximum
distance is about five to six meters. The key here is that there\'s all
these different waters being boiled. It\'s not the same water being
re-boiled, getting more minerals from the rock, again accumulating
minerals because imagine this matrix blocks here after 10 years it
starts to boil and then it boils all of this water off, leaving a tiny
bit of salts there because the water is really benign. It\'s only 1,000
milligrams per liter total to salt solid, which is very low. There is
almost no salts at the start. Then it moves to the next one and it
starts to boil that water off. So there\'s no accumulation of salts.

Now, if steam moves out here and it condenses here, and it condenses
here and starts to pick up some minerals, but it doesn\'t have a lot of
time to pick up minerals because it will move down, okay? Steam here
will have a little more time because it\'s directly above it. It has no
more residence time. It might take up a little bit of minerals and then
it\'s going to shift this way. And you get new steam, new condensation
and again almost no mineral in the water, so we are getting rid of
minerals in opposition to I think their conception of their model where
we are accumulating minerals.

Now, their conceptual model says let me just consider this front
stationary, and all this barrier here and all this has a heat pipe.
It\'s not dry, it\'s a heat pipe now, which is not the case in our
models, or in our drift scale observations, and we always condense here
and pick up minerals and that water can\'t go anywhere because it\'s a
closed system. It picks up minerals, then moves and brings the minerals,
then boils again and it starts to concentrate fix, if you will. I think
that\'s the difference. So we believe you are getting rid of chemicals,
you are having cleaner water because you don\'t have time to pick up so
many minerals because you\'re always replenishing it with more and more
steam, whereas their conceptual model is a closed system where you
can\'t get rid of anything. That\'s how I read it.

CHRISTENSEN: That\'s very helpful. Thank you.

CERLING: Cerling, Board. We\'ve spent a lot of time on these pictures
and I\'m going to leave them here, too. And maybe this is better
answered by Carl, but I\'ll ask it now because it has to do with time.
And so in your model you would have the water getting cleaner for a
period of time. Before boiling we\'d be getting seepage water that has,
let\'s call it ambient chemistry. So how long after the vaporization
barrier disappears would it take to return to this ambient chemistry in
your model?

BOVARDSSON: I think you\'re absolutely right. I think it\'s better
answered by Carl. Carl is going to review the chemistry. He\'s going to
handle the drip shield and I think it\'s better answered by him because
you\'re right. Even though the seepage, we assume there\'s no seepage
during the thermal period, even after the drift wall temperature goes
below boiling, it starts to get seepage. There are thermal hydrological
processes in the rock that take place and manipulate the water so it\'s
not the same as the ambient water. So your question is\--so I think Carl
can address that. Or we can address it later on.

STEEFEL: We have slides on that.

PARIZEK: Parizek, Board. Just a couple questions. One, I was having
problems with the steam always being in the repository. If you\'re above
boiling and dry out all the rocks around the opening, eventually you
ought to get rid of your steam, shouldn\'t you? Shouldn\'t it be
steamless after a while. Maybe on the ends?

BOVARDSSON: Yeah.

PARIZEK: You said there was always going to be steam in there.

BOVARDSSON: No, no, sorry. I apologize for that. What I think is going
to happen there, and our model itself has shown this, is that we start
to boil in the rock and when you boil in the rock, you start to generate
steam. When you boil in the rock your pressures, your gas pressures
increase in the matrix below there because it\'s tighter to get the
steam out and therefore the gas pressures also increase slightly in the
fractures, 10 to 100 Pascals or so. So steam goes both directions. It
goes out in the rock, it goes back in the drift. Now, the steam
generated in the drift can flow laterally to the cooler part of the
drifts and condensate there and cool down, away from the packages. Then
later on when boiling stops, obviously, the mass collection of air in
the drift is going to return back to all air. So it would be mostly
steam, I believe, even though I think Dan\'s comment is a good one, all
steam, but there\'s going to be counterflow of air, of steam in the
drifts because of diffusion and dispersion processes that\'s going to
equilibrate concentrations, but it obviously will go all back to air.
Does that answer your question?

PARIZEK: Right, but\--Parizek, Board again. As the rock is drying out
and you could have the steam go both ways, is there some distance into
the rock after which the steam only wants to go away?

BOVARDSSON: No. No. There\'s always going to be\--

PARIZEK: Always some return?

BOVARDSSON: You pick a block here that maybe increases in pressure in
the matrix block by a few hundred Pascals, and then that boils away and
then this block increases and so you\'re always going to have some
gradient this way and some gradient this way. But the gradients are
going to decrease with time because you arrive, because the pressure
increase here is going to be similar to that here, but the distance is
longer so you\'re going to get less steam flowing into the drift at
times just because of distance. You understand what I\'m saying? It is
always going to be both ways. That\'s my conceptual model.

PARIZEK: The Board also has a concern of the axial, flow along the axis
of the drifts.

BOVARDSSON: Yeah. Yeah.

PARIZEK: Because of unevenness of the heating and then the cold trap
effect so, and these are some of where our points come from. On page 19
you show the seepage threshold values and the various variables that
went in there. I guess in there is also lithophysal facts.

BOVARDSSON: Yes.

PARIZEK: And so that\'s caught up in the TSPA.

BOVARDSSON: Yes.

PARIZEK: Now, was it always in TSPA quite in that form or is this new?
Are these new data?

BOVARDSSON: Well, it generally has been like this for years, that we
actually had the sensitivity to those repositories, but they are
dependent upon which unit they are in, what the permeability of what
units they are in and all of that, so we still sample this. We also have
new curves for drift degradation that took into account that the drifts
were collapsed, fully collapsed and then we modified these.

PARIZEK: So that would be the new part?

BOVARDSSON: Yeah, that\'s totally a new part. But we always continue to
modify as more data come in and our certainty reduces then we change
this to reflect the new data, but the changes are subtle. They are not
harsh changes.

PARIZEK: And then on Figure 21 you show films which the Board is also
interested in, but on rough surfaces are there times when film flow can
give rise to drips, just because of rough surfaces?

BOVARDSSON: Yeah.

PARIZEK: 21 shows, you know, in a matter of speaking.

BOVARDSSON: No, you\'re absolutely right, and we see that in our seepage
experiments because you might, it starts out with vets in the ceiling,
and then it starts to go sideways and then you form drips that collect
in the seepage collection rate, so that\'s taken into account. Yes.
Absolutely.

PARIZEK: Thank you. That could occur in any location?

BOVARDSSON: Right. Any location, yes.

PARIZEK: In the drift walls ceiling.

BOVARDSSON: Yes, so that\'s why our collection system for the seepage
extends over the entire thing. It\'s not just done to where we expect
the seepage to be.

PARIZEK: And you mentioned that there was no seepage observed to date in
lower lith. Yesterday we saw droplets of water that Mark Peters showed
us, but I guess he would attribute that to condensation and you would
attribute that to condensation. That\'s your consistency then. That\'s
not seepage, in your opinion.

BOVARDSSON: Yes. I think the\--no, we have some geochemical information
from Zell Peterman and others that indicate that the chemistry is very
little in this water. It\'s almost no silicon, no chloride, if I
remember correctly, in some of these samples. So it\'s not consistent to
seepage water. So it\'s very likely to be condensation.

PARIZEK: Figure 54 was your movie, which was very nicely done.

BOVARDSSON: John Buschek\'s movie.

PARIZEK: But the movie didn\'t show anything about permeability,
variability in any of the repository footprint locations, like fall
effects or something. Only edge effects as a result of cooling. Does
that mean there are no fast pathways anywhere in that footprint?

BOVARDSSON: No. No, there are fast pathways. The thing is, though, the
thermal signature is dominated by conduction. Conduction is a diffusive
process which is a large process and that\'s why low conduction is a
thermal conductivity done not a heck of a lot because the large
conductivity matters. Faults do not affect the large scale thermal
properties. They are going to be the same along the faults, unless the
material is different or the radishio (phonetic) or something in the
faults. So the movie is not going to depend a lot on flow and faults or
things of that sort because it\'s so dominated by heat conduction.

PARIZEK: That would mean that the Chlorine 36 issue and so on, the
amount of water is trivial, I guess. You\'re saying it\'s
conduction-dominated. I mean you really have damn little water flowing
through that system in the time frame of your model.

BOVARDSSON: Yeah, well, I have all this stuff. The Chlorine 36 is not a
big issue because such a small amount of water is actually the fast flow
of Chlorine 36. So I\'ll always say it\'s not a real important issue for
performance. Might be a real important issue to make sure we understand
from a physics point of view, but I don\'t think it affects performance
in a big way.

PARIZEK: And Figure 37 deal with the analog value of geothermal
reservoirs. And, in that sense I guess the program has the geothermal
reservoir analog somewhere in its story. Is that right?

BOVARDSSON: Yeah. Trafalgar (phonetic) has done work in Maraki in New
Zealand with materials, it has done work in Yellowstone on geothermal
systems, so there has been work on geothermal system and analogs to
Yucca Mountain.

PARIZEK: Tied specifically to the water flow issue as you were\--

BOVARDSSON: It has not been tied directly to the thermal seepage issue
like I did. That\'s not\--

PARIZEK: Okay, that\'s new.

BOVARDSSON: That\'s new.

PARIZEK: Because we would like to see the analogs used in the most
direct way possible rather than\--it\'s a list, but the listing is
useful and if you can then say well, what about the analogs used for
some specific process you\'re dealing with. I think you\'ve just stated
it today perhaps for the first time. Anyway, it\'s different than
what\'s in the analog discussions.

BOVARDSSON: Yeah. That\'s a good point.

PARIZEK: And then one last point. As you boil the water off, my tea
kettle always has something left behind and I don\'t know what\'s in
there, but if you reflux water through it, I imagine the water is going
to be so clean. And you stated before the water is going to be refluxed
out, moved out the side, the lateral movement of it, and always the
salts are going to be very dilute and very small quantities of it, so it
can\'t change the chemistry much. But I guess we\'re going to hear this
when we get into the drift scale tests as to what water chemistries have
been collected in order to support that statement?

BOVARDSSON: Yeah, but let me clarify that a little bit. What I was
explaining is the conceptual model for boiling and shedding. So we get
rid of some of that water and some of these minerals with time.
Certainly, in the matrix block there\'s going to be some salt left
because you boil all the water off. But that amount of salt is very
small because the water is so dilute. It\'s only 1,000 milligrams per
liter or something like that. So it\'s a very small amount of salts, but
when you start to reflux back and the mix-model, the TOT models show
this, you pick up that water, you pick up that salt and you have high
concentration in the beginning because it\'s coming to a little bit of
salt, so I think Carl will talk about that a little bit.

PARIZEK: And that\'s kind of an important point because refluxing source
of salts is one way which you can visualize it being high concentration
where it didn\'t go laterally, but finally cascades back through these
small little packages that have small amounts of salt accumulatively,
not a lot of water, but quite a bit of salt before you\'re done.

BOVARDSSON: Right. Yeah.

STEEFEL: Steefel, LPL. Just to make clear, though, that use of the term
refluxing by the State of Nevada seems to be somewhat different where
they basically cycle reconcentrated water continually back so that it
develops somehow a large pool of concentrated water. What Bo was
explaining is it\'s basically a one-way transport so the salts that are
left behind are basically whatever you could get out of that ambient
pore water, precipitate those out varying rewetting which is the
preferred phraseology I think to refluxing. You do pick up those salts
and that\'s what Bo mentioned. That shows up in all the models. I\'ll
show some slides. But it\'s not this heat pipe refluxing thing that the
State of Nevada is discussing.

PARIZEK: Parizek, Board. The figure 46 though on the end might be your
worst case. I mean one long fracture and all of the steam, a lot of
steam trying to go up the fractures, maybe that vaporization zone is
much longer up a fracture like that? So again you can sort of see more
salt accumulation along that fracture if that holds?

BOVARDSSON: Could be. Any other questions?

DUQUETTE: Thank you, Bo. Don Shettel, do you want to comment on the
interpretation of the reflux data by Livermore.

SHETTEL: Yes, I\'d love to comment on this. I think there has been some
mischaracterization of the refluxing zone. We believe that the refluxing
zone is like a heat pipe above the repository. And Bo\'s explanation is
not clear. He says that condensate comes back down and is dilute. Well,
yes, if it condenses up in the cold rack and comes down it doesn\'t have
much time to pick up any dissolved solids. And it\'s dilute. But if
it\'s condensate coming back down, to me that seems to imply that he is
allowing some refluxing. And we don\'t\--our system is not a closed
system as he has characterized it as. We believe over time as one of my
slides showed, you get some condensity lost over the sides of the
drifts, which is consistent with some of Bo\'s modeling. And, by the
gradual net loss of condensate over the side, you do allow some
concentration of solutions in the boiling zone. We\'re not saying
you\'re getting concentrated solutions coming back down, but that the
concentrated solutions develop at the boiling front. So over time, it
starts out initially dilute, as he says, but we don\'t believe it stays
that way. Over time loss of water and compensate over the side with the
net percolation and refluxing that the concentration builds up, and
it\'s not a closed system, some compensate is allowed to be lost over
the side so therefore it is an open system.

DUQUETTE: Thank you very much.

BOVARDSSON: Just to clarify that a little bit, too, I think what this
gentleman says would be true if this was an entire heat pipe region
where actually water would go back and evaporate in and go back up.
It\'s not. Our drift scale test results have shown this is super-heated
region with no heat pipe present here, and there is therefore no heat
pipe in here. There\'s only a heat pipe process boiling point up here.
So there\'s always different regions of boil and therefore you cannot
concentrate waters. That\'s our conceptual model.

DUQUETTE: Thank you.

BOVARDSSON: According to our drift scale test.

DUQUETTE: Thank you for your presentation and the discussion. Some
questions?

DIODATO: Bo, thanks for your presentation. Diodato, staff. Just one
quick\--there are number of issues we would love to have the opportunity
to discuss with you, but let\'s just use one, stay with the thermal
hydrology question. Mark Peters yesterday shows a slide 10. John, I
don\'t know if you can get that up, on the one side. And, compare that
with your slide 36 from your presentation on the other slide. Now the
slide 10 is matrix saturation. That\'s actual data, and so that\'s from
the drift scale test, right? And there\'s, the 100 degree isotherm there
and the 120 degree isotherm, there\'s still like 80 to 90 percent water
saturation in the matrix. So first, I\'m curious about how this water
continues to persist at above 100 degrees and maybe that\'s a
concentration effect being the total ionic strength is larger there, but
then, why wouldn\'t there be a gradient between that number and then the
fracture saturation on the left where you could have some matrix
fracture interaction of flow? And, maybe mechanical transport. Is that
possible? I mean is that, I\'m just curious, I mean I look at this data,
right.

BOVARDSSON: I think time is out, David.

DUQUETTE: Saved by the bell.

BOVARDSSON: Let me explain that I didn\'t look carefully at Mark\'s
slides yesterday, but let me explain something here. We vary our boiling
in the matrix blocks, the pressure goes above the ambient 1-bar
pressures because it starts to boil and you increase volume because the
volume of steam is a lot more amounts of water and then you increase
pressure to get the steam out because you\'re continuously going, okay?

DIODATO: So this is a lower permeability, you have almost a closed
system.

BOVARDSSON: Because of lower permeability. So the temperature in the
fractures would be 96 degrees or close to it, but the load is higher
because the pressure there would increase by 10 or 100 Pascals or
something like that. So there is going to be a region here where perhaps
because the pressure is a little higher, the temperature is a little
higher so that you don\'t have a sharp interface there because you
haven\'t boiled up all the water in those matrix blocks.

DIODATO: So there would be both the pressure and the thermal gradient
between the matrix and fractures?

BOVARDSSON: That\'s exactly right.

DIODATO: So that would tend to transport water.

BOVARDSSON: That will transfer steam, get rid of the steam from the
matrix blocks.

DIODATO: All right.

BOVARDSSON: So I think that\'s reflected there to some extent. That\'s
my interpretation, although this is Mark\'s slide.

BOVARDSSON: That\'s smaller. Okay.

DIODATO: Which is model? The water saturations or the temperatures?

BOVARDSSON: Both models.

PETERS: Both models.

DIODATO: There\'s no drift scale data.

Next slide. Yeah, so that\'s data. That\'s less clear.

BOVARDSSON: No, I think this point is very clear.

DUQUETTE: I think we\'re going to stop the discussion here. We\'re, as
usual, running a little bit late. Let\'s hold the break to about 10
minutes and we\'ll steal some time from the lunch break.

(Whereupon, a brief recess was taken.)

DUQUETTE: The next presentation this morning if people will please take
their seats. Thank you. The next presentation this morning is on the
in-drift chemical environment during the above boiling period presented
by Carl Steefel.

STEEFEL: Okay, thank you. We\'re going to split here. I\'m going to be
presenting two talks and basically splitting what\'s broadly referred to
as the thermal pulse into two periods. The first one, the above-boiling
period and the second one will be the below-boiling period. By boiling I
mean when the drift wall reaches the boiling temperature of 96 degrees.
I think it divides the talks up nicely into a distinct set of key issues
that makes it easier to grasp.

And so I\'ll make the acknowledgement. I\'ve had a lot of help on this.
I\'m just mostly the spokesman here but in terms of the in-drift
chemical environment, Greg Gdowski, Susan Carroll and Tom Wolery,
significant contributions from Zell and Tom Wolery. And then, the THC
and the issue of acid gas volatilization from the group at Lawrence
Berkeley, Nick Spycher, Eric Sonnenthal and Guoxiang Zhang.

So as an overview of the presentation, I want to begin with just a short
statement on the effect of the thermal hydrologic environment on the
in-drift chemistry during the above-boiling period. Why is it that
we\'ve got special issues because of the thermal hydrologic regime, and
then I\'ll launch into a first look at salt deliquescence, go on to what
salt minerals in dust are found in the repository and ask the question
specifically can they generate calcium chloride or magnesium chloride
brines. Then look at the issue of stability of these salt minerals or
salt mineral assemblages at temperature and different RH values.

And then, there\'s a natural lead-in from that topic into the topic of
acid gas volatilization from salt assemblages at temperature and
specifically what\'s going to be their fate in the drift environment.
This is focused on the drift environment. And then return for another
look at salt deliquescence with a focus on the multi-component aspects,
asking the question how much water is absorbed and what composition
brines can actually develop, and then I\'ll conclude.

So first just briefly recap the THP environment and the effect on the
in-drift period, the in-drift chemistry during above-boiling.

The issue here is that focus is where the drift wall temperatures in
this rock are above boiling, which includes a relatively short heating
period that dries out the drift and rock and then a much more extended
period in which the drift wall gradually cools to the boiling point of
water in which, as Bo has made a strong case, there\'s no seepage of
water possible. Given this, the key issue during this period are the
deliquescence of salt originating from dust accumulated on the waste
package and the related issue, possible generation of acid gases from
the deliquescent salts and their fate in the drift environment. And, you
can see here, the key to this first point about no seepage is taking
credit for the vaporization barrier on top of the capillary barrier.
It\'s not to say that no seepage will ever occur, but it\'s an extremely
low probability, extremely rare event and so we\'ve got a whole
different set of issues, basically dust that we can focus on during this
period.

And so, this is the period we\'re talking about. This is a slide that\'s
going to be shown later by Joe Payer with the ventilation period number
one and then a heating period after ventilation. We\'re basically
concerned with the whole heating and cooling period until the waste
package temperature\--I mean rather the drift wall temperature drops
down to 96 degrees, so that\'s right at this point. So we\'re concerned
with something on the order of this kind of time frame.

This is an average waste packet. You can see the characteristic sort of
patterns, though. The drift wall obviously is a little bit cooler than
the waste package, and this important gap in temperature creates a
difference in RH, of course. And the RH is shown on the waste package
inverse as people have pointed out relative to the temperature with
lows, the low here is about 30 percent. Some waste packages or drifts
will actually drop to below 20 percent. And then basically comes up to
about 65 percent RH at the end of the boiling period.

So we\'re going to basically be looking, if we could see the next slide,
at a somewhat limited range of temperature and RH distributions here. In
fact, when you take time out of it and consider, as Bo showed in that
movie, that various packages move through this whole thermal history at
different times, if you take time out of it and look at just RH and
temperature, a lot of this variability collapses into a much more
limited range of conditions. So for example the average waste package
would reach the boiling point at the drift wall at this time, so we\'re
basically in this talk concerned with a typical temperature RH
trajectory up to about 65 percent, perhaps a little above that. So
we\'re going to focus on that period.

So I want to start with this salt deliquescence. And the issue here is
that dusts originating in the repository, this is a review of course,
are brought in by ventilation, may contain salts that deliquesce at
relative humidity, less than 100 percent. Well, what is salt
deliquescence? It\'s, first of all, the activity of water times 100
equates to the RH. That\'s the activity of water in the atmosphere. So
the idea is that the activity of water and equilibrium with the salient
brine is lower than one in every case. Pure water has an activity of 1.
So these brines will absorb water when the RH, that is, the activity of
water in the atmosphere is greater than the activity of water in the
brine. And for highly deliquescent salts this also implies that a brine
will always exist above the boiling point of pure H2-O. This is the
so-called boiling point elevation. Next slide.

And this is just showing\--I\'ll show this quickly here, showing here
that body and vapor pressure water versus temperature for different
activities of water, for example, pure water activity of one, you can
see that the repository pressure boils at 96 degrees centigrade, 100
degrees obviously at sea level. You can see, though, if you reduce the
activity of water, for example, the .75 then this would be a water
equilibrium with a saturated sodium chloride solution, we raise the
boiling point up to about 108 degrees at sea level, about 106, as I
recall, at the actual repository pressure.

And so the deliquescence, you\'ve seen some of these slides, RH for some
of these salts. Shown here, for example, calcium chloride pieced
together is the sum of a variety of phases of different states of
hydration, but they cluster quite a bit here. This is the so-called
deliquescent RH curve, below it RH values in the drift environment,
below that, that salt, if it was present, is going to be dry. Any time
that RH comes above that deliquescence RH curve, you\'re going to start
to absorb water and you\'re going to wet up this system. You can see
it\'s about 20 percent for calcium chloride. For these other salts
halite shows very little temperature dependence right there at 75 to 74
percent. Soda niter, much stronger temperature dependence. You can see
here also that the combination, the assemblage halite plus soda niter in
every case will have a lower deliquescence RH that\'s basically the
combination of those two salts there.

And this is a slide that kind of summarizes some of the chemical
behavior. I\'ll come back to this towards the end of this talk and again
in the next talk. These so-called eutectic slides used to give me
headaches and igneous petrology, but I think they are worth going
through briefly. The point is that if you\'ll look at RH versus, say
nitrate chloride ratio for the system, sodium chloride, sodium nitrate,
as the RH rises initially you\'ve just got these two salts are dry. Once
at a particular temperature it hits the eutectic point at 120
degrees\--that would be about 55 percent\--you form or start to form a
solution. It absorbs water there.

However, if you had a bulk salt that was\--salt that had a bulk
composition of say, 0.5 just for argument\'s sake here, you don\'t
actually initially form that composition. You form the so-called
eutectic composition and gradually then as you raise the RH you migrate
along this solvus. It\'s only once you get back to this bulk ratio that
you can actually leave that solvus, then you\'ve basically dissolved all
your salt and you get back your bulk salt ratio. The reason I\'m going
on about this is really to make the point that the thermodynamics of the
system is actually, in some cases, adjusting very significantly the
ratio of nitrate to chloride you have in the system. So I\'ll come back
to that point.

So on the salt minerals in the dust actually found in the repository.
The point is that, due to lack of seepage during the above-boiling
period, the salt-bearing dusts are the chief concern because of their
potential for deliquescence. Small amounts of soluble salts are found in
the repository dust. Higher amounts are expected if atmospheric dust
became a more important component of those dusts, but I\'ll review the
actual concentrations and fractions of the different cations and anions
there. Chief concern of course is the chloride-bearing salt because of
their potential for corrosion of the Alloy 22.

And so what has been done by the USGS as part of the project is to
collect dust from the various tunnels. This is part of the dust
collection in phase 2. They basically took surfaces and vacuumed them.
There\'s one of the vacuumed surfaces. Here you can see the original
dust that was developed on the rock and placard, so you\'re actually
able to estimate amounts of dust that are coating these various
surfaces. I\'ll make use of this a little bit later on.

And the next thing then is the actually analysis. These were analyzed,
it would be nice to just go in and

x-ray these and know what salt minerals were there. The problem is the
salt contents are extremely low and they are below the detection limit
of normal x-ray to fraction methods. So what was done is basically to
determine the soluble content of the dust by subjecting the samples to a
distilled water leach. And then basically\--well, first of all,
obviously you get out the proportions of nitrate and chloride. Chloride
in that system and the various

cations\--I\'ll show you that in a second\--but in addition, in terms of
identifying what primary minerals were actually originally there, we
follow two paths here. One is to then evaporate these leachates to yield
salt minerals that are going to be present in a small enough, in large
enough concentration. Now we don\'t have the dilution with all that
inert dust, and these can actually be identified by

x-ray diffraction. And a second way is to determine the primary salt
minerals via calculation, using an equilibrium mass balance evaporation
calculation, EQ3/6 that basically takes the water out, reverses the
leaching experiment, pulls the water out to come back at it. Implicit in
this is some equilibrium assumptions I\'ll discuss briefly later. But a
key point is that it does observe a rigorous mass balance in terms of
the overall system of chloride nitrate, whatever is in there. It
observes that mass balance. You can kind of think of that as something
like a normative salt composition.

And so, here is the average of the soluble cations and anions, and I
probably should have put this on the second slide, but that\'s all
right, just to point out a couple things, there\'s a fair amount of
calcium, but I want you to note that there\'s also quite a bit\--this is
plotted in terms of milli-equivalents per kilogram dust. That\'s like
mols multiplied by the charge. There\'s quite a bit of sulphate and
carbonate. Some of those actually exceeds the calcium.

I want to also point out there\'s some chloride, as you would expect,
but this chloride in every case is actually less than the sum total of
potassium and sodium and cations, and there\'s also nitrate in the
system. So try and keep this plot in mind and we\'ll come back to it as
we need to.

And so here\'s the results of the actual x-ray diffraction analysis of
these salts precipitated from the evaporated dust leachates. And it
shows as the dominant salt, as you would expect, is sodium chloride
occurring in all the samples. Major abundance in samples two through
five. Also getting calcite in one of the samples. And also significant
amounts of sulphate. This is gypsum, this is basonite, another hydrated
version of calcium sulphate mineral. For some reason due to the analysis
we\'re not able to pick up the nitrate minerals and we\'re actually
picking up ammonia minerals whether that\'s anthropogenic effect from
the drilling or whatever needs to be resolved. But there is some of
those there, but the dominant mineralogy is this sodium chloride salts
and the sulphates.

This is also corroborated in general by the calculations which predict a
series of main key assemblages, salt assemblages. 68 percent is actually
typified by this assemblage of sodium chloride and potassium nitrate.
The bromide is basically drilling activities and testing, so in a normal
repository setting, you wouldn\'t have significant concentrations of
bromide. You can see this is a similar assemblage. We\'ve only added the
soda niter here. So no calcium chloride or magnesium chloride salts are
predicted. None were observed in the actual evaporation of the leachate
that I showed in the preceding slide.

And so here is a comparison of the different soluble salt contents in
the ESF here, reported by Peterman, you can see we\'ve got about .3 to
.4 percent soluble salts. So it\'s quite low. You can see now why we
don\'t x-ray these things. X-ray in general has a hard time below 3 to 5
percent. In contrast, atmospheric dust has a higher soluble salt
concentration. So if these became more important obviously you could
bring this number up.

And so the question arises then, can the salt and the dust generate
these calcium chloride brines? Well, we have to say a calcium chloride
brine is possible only if the following conditions and the soluble salt
faction are both satisfied. Number one, calcium has to be greater than
sulphate plus carbonate. The reason is that calcium sulphate, gypsum or
anhydride and calcium carbonate, that\'s calcite, are relatively
insoluble. So you\'ll tend to pull your calcium out of solution to the
extent that those anions are present.

Secondly, chloride has to be graded in sodium plus potassium, same sort
of argument. Sodium chloride and potassium chloride are less soluble
than calcium chloride. They\'ll precipitate earlier. 96 percent of the
tunnel dust failed to satisfy this first condition. The remainder, about
4 percent, satisfy the first but not the second condition. But we don\'t
see from the data we have that there\'s any way in which calcium
chloride could ever be a significant part of these dusts here.

Similar arguments for the magnesium chloride, except now there\'s three
conditions. Magnesium graded and carbonates, same sort of argument. This
is an insoluble phase, drops the magnesium out. Same argument about a
chloride. And then additionally a low silica environment since magnesium
is likely to be tied up in silica. There was some discussion about
sepiolite yesterday which is observed for example in experiments run as
part of the opalinus clay study in Switzerland. Sepiolite was actually
identified there. Turns out what mostly is observed in the evaporation
experiments run at Livermore, is a magnesium sheet silicate, either
smectite or some other sheet silicate. So there\'s nothing absolutely
required or special about the presence of sepiolite. The point is that
magnesium silicates tend to form. And this is of course observed in
other environments. If you look at Mid-Ocean Ridge circulation of sea
water which is loaded with magnesium, it\'s well known that that water
when it circulates through the higher temperature rock is basically
stripped quantitatively of magnesium. So I think pretty much all
geochemists accept that this reactivity of magnesium with silica is a
well known phenomena. But the point here is that none of these
conditions occur within the repository.

Another point to be made is if the presence of calcium chloride or
magnesium chloride minerals in outside dust is very unlikely. The
minerals are known to exist on the earth\'s surface at only a few
places. For example, in Antarctica. This is the type locality for the
mineral antarctikite. The few known surface occurrences appear to be a
ephemeral. The key point here is basically that very low RH conditions,
less than about 25 percent, are required to preserve these salts
in-situ. And these low RH conditions obviously are even harder to
maintain during transport of salts. So in other words, even if you could
make and maintain under extremely low humidity conditions a calcium
chloride salt, you\'ve also got to transport it to Yucca Mountain
without it ever seeing above about 20 percent. Otherwise, it deliquesces
and it solubulizes.

And let\'s jump forward. I did put one out of order here. Sorry about
that. After all this I put one out of order. I should be up to 26, not
36.

And so this is just showing comparison of the soluble ionic ratios. This
is actually\--might just skip this because Don Langmuir showed various
similar data basically showing the ionic ratios of tunnel dust and
Nevada rainfall, which as he showed is quite similar to the atmospheric
dust. But you can see in general that even if the atmospheric component
goes up, still we\'ve got very similar sorts of mol or ratios developed
here in the tunnel dust forward to about 1. Here in the Nevada rainfall
we get very similar sorts of ratios of nitrate and chloride.

So we don\'t expect a completely different story if, during ventilation,
the atmospheric component became more important.

And, well, the previous one was really just the intro. It\'s not that
important, just says we\'re going to talk about stability of these
minerals. The point here is, as I\'ve said, although it\'s not expected
based on the preceding arguments, the stability of calcium chloride and
magnesium chloride have been evaluated experimentally. And a good
portion of the calcium chloride data is new to the Board, I believe, and
all of the magnesium chloride data is new. The stability of sodium
chloride which is expected to be present in small amounts, as I\'ve
said, in the dust, has now also been investigated experimentally. All
new data here I\'m going to show. And these have been evaluated using
TGA analysis under controlled temperature and RH conditions.

Here\'s just a quick picture of the apparatus. Basically shows the
sample chamber. These were actually originally designed as corrosion
experiments with the Alloy 22 in there, obviously. I\'m not going to
talk about that. I\'ll leave that to Joe Payer if he needs to. My issue
concern is just the stability of these salts, but you put it in there
and then you control quite closely both the temperature and the RH in
that chamber so you can raise the RH and know where you\'re at. It\'s
sensitive to weight changes as small as tens of micrograms.

And here is the results, as I say, some of which you\'ve seen at least
this calcium chloride at 150. Most of the rest of it I don\'t think
you\'ve seen. This shows both the calcium chloride and the magnesium
chloride system. At 100 degrees calcium chloride is aqueous films, are
stable for the duration of the test. And just to remind you what you\'re
seeing here is basically a very rapid initial weight gain as the salt
deliquesces at 22 percent RH in that temperature, and then if it\'s
stable, obviously it\'s going to just stay at that with the salt, with
the water maintained there. That\'s what\'s happening at 100 degrees.
And I believe Doctor Duquette was saying at 105 you could make a stable
solution. This would seem to be the case. At 100 there\'s no problem
with stability. Soon as you start going to 125 though we start to see
that characteristic, weight loss, forming insoluble precipitates.

At 150 degrees down here we see the solution evolves rapidly over as
little as two days forming insoluble precipitates and also generating an
acid gas, HCL. It\'s most likely that the same thing is happening as
mixed system. This is new data. Calcium chloride plus calcium nitrate
with volatilization of the hydrochloric\-- it\'s a lower rate probably
just because of the dilution effect of the nitrate, calcium nitrate
that\'s present there. You can see also that magnesium chloride
basically transforms within hours at all temperatures considered in each
case becoming non-deliquescent at these RH conditions.

You can see there\'s the magnesium chloride number at 125 and the number
here, the green, at 115. So there\'s no stability to these magnesium
chloride salts.

When you look at sodium chloride, this is all new data again. Sodium
chloride does appear to be stable at 105 degrees. For reference boiling
point of sodium chloride saturated solution is 108.7, so we\'re a couple
degrees under that. Seems to be some evidence for transformation of this
assemblage. It\'s not clear at this point what that\'s due to. Most
likely it probably is volatilization of a little bit of HCL, which is
now occurring because we\'re able to bring this solution up to 120
instead of 105 because of the lower deliquescence point of that mixture,
as I discussed earlier.

And so in terms of the characterization of these deposits, formations,
electron dispersive spectroscopy indicates precipitates contains calcium
chloride and oxygen. The analyses also indicate a loss of chloride,
particularly in the case of the 150 degrees centigrade one. A chloride
relative to calcium indicating volatilization of the hydrochloric acid
as a gas. This is conducted under open systems where you continuously
flush through a gas of known RH, but also with basically zero HCL in the
atmosphere. Spectroscopy indicates a precipitates or not, calcium
hydroxide or calcite, so it looks like it\'s most likely a calcium
hydroxyl chloride that\'s been formed as a combination of the loss of
the chloride, but probably more importantly the loss of this acid
component which allows the PH of that solution to go up a little bit and
precipitate. The point is that 22 percent RH again, this is a
non-deliquescent salts. So we\'re not able to maintain these highly
deliquescent salts at temperatures, in films under open system
conditions.

And so the summary, I probably just gave the summary. We\'re able to to
these experiments and show the calcium chloride transforms the
non-deliquescent phases. Deliquescent magnesium chloride is unstable at
all temperatures investigated above 100. These are the results of our
HCL volatization for which there\'s a strong temperature dependence
observed. Calcium chloride doesn\'t seem to volatize at 100 whereas it
goes very quickly at 150. And here\'s a point where I was going to make
here is that perhaps this is what the Board was referring to when they
talked about conflicting evidence about calcium chloride as corrosion
potential. I think the point here is that where nobody is questioning
the potential of calcium chloride to corrode the various alloys at
temperature. In other words, those are good experiments. The issue is
whether those salts are stable as thin films under various RH conditions
under open system. If there was purely a corrosion issue, I wouldn\'t
even be up here. Joe Payer would be discussing it. And so it seems to be
open system behavior. In other words, if you construct closed system
version of this where the HCL in the atmosphere builds up and then
finally came to equilibrium with HCL in the actual brine, you\'ve shut
that devolatization and transformation process off completely. So it
occurs under open system conditions where you can flush that gas out of
there.

It\'s our contention as I\'ll try and show in the next slides, that the
drift environment is very much an open system and therefore that PGA,
while the actual transport rates may not be dead on, is much closer to
the real situation than a closed system. That\'s the key, though, I
think, is that we\'re not saying calcium chloride doesn\'t corrode.
It\'s simply that that assemblage is not stable at temperature as a thin
water film. Obviously, if you made a large solution of it, you could
maintain that for quite a while, and that\'s, of course, the way the
corrosion experiments are done.

And so that basically leads naturally into the next topic, the
volatilization of acid gases in the drift environment.

And basically, we\'ve said that the instability of these salts to the
extent that they are present, we don\'t think that they will even be
present, but it would be due largely to degassing of HCL. HNLC gas is
much less volatile than HCL gas so the primary issues with HCL gas, so
the question is what will happen to any acid gas generated in the drift
environment and how much acid gas will be generated. May be just as the
back of the envelope because as I said, we don\'t expect under normal
conditions even to find any salts there. But I\'ll try and address those
issues in the next slide.

This is our view of what happens, would happen to an acid gas in the
drift environment. Basically, under open system conditions, any HCL gas
that is generated will disperse in the drift. And in fact, as I\'ve
shown you from the TGA results, normally you\'d expect that if it\'s
going to occur to happen at the highest temperatures. That\'s going to
happen, therefore, when you\'ve got the benefit of this vaporization
barrier so the entire drift environment is going to be well above
boiling. There\'s no possibility of condensation. What we\'re arguing is
that this is an open system, basically doesn\'t look anything like a
laboratory distillation experiment, and that HCL that\'s generated is
going to migrate out through the drift environment, through these
fractures until it encounters liquid water. In the high temperature
case, as Bo said, that\'s going to be five to six meters back. And then,
because of the Henry\'s Law Constant for HCL and all of these acid
gasses, it\'s going to partition quantitatively almost into the aqueous
phase that\'s present. So we\'re talking here, not just about dispersal,
like hydrodynamic dispersion, we\'re actually talking about very
powerful sink term in the aqueous phase that\'s going to scavenge those
acid gasses.

And the last point to be made, I\'ll come back to this, that if you\'re
at a lower temperature region where condensation would occur, the last
place you would expect any condensation would be on the waste packages
since they are the hottest spots within this overall drift environment.

I want to just quickly pursue this issue to try and show our view of
these acid gasses with a couple of simulations that have never been
shown before, just done fairly recently, but to start with the back of
the envelope, calculation of what the HCL gas might be in the drift
environment. So, the way we did that, very conservative estimate, was
took the measured mass of dust in the tunnels as measured by the USGS,
then used the measured chloride content of the dust and then, as you can
see again, about 5 milli-equivalents per kilogram of dust, and then
assumed, very conservative assumption, all of the chloride volitizes
HCL. As I\'ve said, normally that chloride should be bound up with
sodium chloride, should be stable, but let\'s just look and see what
happens. We inject it into the drift. Here\'s the waste package, here\'s
the drift environment. The reddish orange is the rock here. Eject it
into the drift under two scenarios, just to quickly look at. One, where
the drift wall is just below boiling so we\'ve just had the rewetting
front appear here. But we\'ve still got the waste package above boiling,
so it\'s dryer there. So there\'s no condensation issues.

The second one, let\'s look at condensation where we actually have this
scenario. I don\'t know if this is what was considered by Catholic
University where down the line in the drift you\'ve got a hotter waste
package boiling away. Humid air comes down towards the somewhat cooler
drift, like this one, and what happens? So we\'ll look at that scenario
as well. Both the waste package and the drift wall slightly below
boiling.

So the first one basically shows that no condensation case. What it
shows is after we inject that HCL it disperses rapidly in the drift
environment, within about one day due to diffusion, dispersion. Over
slightly longer time periods, however, the HCL gas dissolves in the
aqueous phase in the rock matrix here, thus lowering its concentration
in the drift atmosphere. So you can, by two months we\'re basically
going from about 10 to a minus 6 mol fraction, or volume fraction, down
to 10 to the minus 12. So the point here is that reservoir water,
wherever it occurs in the drift environment is going to be a very
significant sink for any acid gases that are going to develop and this
is going to operate over a fairly short time period.

And here\'s the other case now. With slightly humid air coming from
somewhere up the drift, a hotter waste package for example, so we\'re
going to allow for some condensation because you\'ve got both the waste
package and the drift wall below boiling.

What we see, however, is condensation exclusively on the drift wall
because still its temperature is lower and the RH is higher there. We
see the condensation of that lower temperature drift wall, initially
because you\'re condensing very small amounts of water after two hours.
Its PH is quite low. All of that HCL gas got scavenged into that little
bit of liquid water that\'s developed there. After 12 hours we\'ve
condensed more water. Basically now we\'re diluting the low PH with that
given amount of HCL. We do not have a infinite supply of HCL appearing
in this model. This is actually the amount that can volatize off that
waste package. We can see further dilution, so by one day we\'re already
up to PHs of four to five. So the point again is that with water, if it
condenses will not be on the waste package. It will be on the drift
wall. That\'s the last place it\'s going to go. Secondly, is that it
will tend to scavenge any acid gases that are present. If we followed
this longer, we would see this PH signal move over the longer time
periods into the water, into the rock, and even somewhat longer time
periods we get mineral buffering that was described by Don Langmuir,
which is that you cannot maintain the low PH plume anywhere in this
environment.

So the conclusions, sort of a summary here is in the unlikely event that
calcium chloride or magnesium chloride area present, the HCL gas could
be generated during the above boiling period. If this occurs, however,
it would be expected to be during the period when the entire drift
temperature is greater than about 125 simply because, based on the TGA,
we see the maximum volatilization at those high temperatures. And in
that period there\'s no condensation anywhere in the drift environment.
Simply moves out. Amounts of acid gas possible are small, placed on the
mass balances, but even more importantly, any acid gases generated will
be dispersed widely in the drift environment and upon dispersal these
will be dissolved into liquid water in the rock beyond the drift,
pulling down the concentration in the atmosphere. And if condensation of
liquid water occurs accompanied by scavenging, that will take place in
the coolest parts of the drift, not the waste package.

So the last topic is to take another look at salt deliquescence with a
focus on these two issues just quickly, how much water is absorbed, just
to give you an idea of that. And also what the composition brines can
actually develop in this kind of multi-component system.

And the salts present in the dust are expected to contain both nitrate
and chloride. We have reversed multi-component deliquescence experiments
that are used to validate a geochemical model that we\'ve been using to
describe this deliquescence and evaporation process. I\'ll show you one
of those. That\'s all new data. And this, as I said, point out the mass
of water absorbed by these deliquescent salts is very, very small. And
finally, return to the issue there of high temperature and lower RH.
Eutectic composition has a high nitrate chloride ratio due to the
thermodynamics of deliquescence.

And this is some of the experiments done recently at Lawrence Livermore
Lab at 120 degrees. Sodium chloride, potassium nitrate system. Here\'s
the deliquescence of sodium chloride. The deliquescence point appears.
Potassium nitrate, you can see the experimental data here. The red
represents experiments that originally started as solid dust and you
basically raised the RH, and deliquescence occurred, and then you
measure the solution composition. The black initially dissolved the
totally aqueous system where you actually evaporated some of it. And, so
you\'re approaching from the other direction.

And so these are reversals of these experiments. You can see the close
agreement and also the time it took to get that was on the order of 48
hours, indicating quite rapid reaction rates here. So this is some of
our validation data of the geochemical model, which include the Pitzer
database that\'s to high temperature and also high ionic strength.

This is the point I was trying to make earlier about, while concentrated
brines can develop due to deliquescence, we\'re not talking about big
oceans of water. We\'re talking about extremely small volumes. In fact,
for a salt mass of .35 grams we\'re talking about something on the order
of 10 to 100 micrograms, or microliters of water actually absorbed. So
we\'re not even up to a drop or, you know, milliliter sort of volume of
drop, which would be up there. To get up to that point, you\'ve got to
be all the way up to 95. So the point here is that we really don\'t have
enough water mass, for example, to generate flow. You\'re just going to
be holding that moisture within the capillarity of any dust that you
have on the surface.

And then back to this thermodynamic control. You\'ve seen this already,
but the point is between the totally dry conditions of RH and totally
aqueous solubilized conditions at a higher RH, the solution composition
is going to be controlled by this so-called eutectic diagram with
migration along the solvus. The point here really is that if you\'ve got
a bulk composition of nitrate, say at 0.5, the thermodynamics in this
system is always going to give you actually higher nitrate chloride
ratios. So it\'s really only when you climb way up in relative humidity
that you can get out these bulk values, and those are shown in the next
slide.

I\'ve been holding this off. These are the actual data from USGS showing
the nitrate-chloride ratios in the solvus. They are actually pretty much
favorable anyways for the whole corrosion scenario. You can see that
almost all of them are above 0.5, but the point is that in this system
these ratios actually represent minimum values because at lower TH, the
thermodynamics of the system drive the solution to even higher
nitrate-chloride ratio.

And this observation is bundled a little bit in the next two slides. The
first one, sort of a schematic that shows possible fields and relative
humidity, temperature. This is an inaccessible region where the pressure
of water would have to exceed atmospheric. You can\'t reach this because
of the pressure unless you run an autoclave experiment.

Here, below this deliquescence point, the system should be totally dry.
We don\'t obviously have calcium chloride salts in this system. We\'re
considering this system. But the point is that there\'s this region here
where nitrate-chloride ratios are always going to be greater than 0.5
and that\'s because of the thermodynamics, just not the bulk salt
concentration. It\'s only once you get up to the 70 percent that you
have a possibility of even moving below that value.

And so, on the next slide, if we look at the characteristic temperature
RH, first for the repository, let\'s focus on the blue one. That\'s the
most common. This is kind of the hot one. That\'s a much colder one.
Focus on the blue one, you can see that drift wall gets to 96 degrees in
about 750 years. In fact, that waste package in the drift environment
spent its whole period above boiling in this region, either under
totally dry conditions or if deliquescence occurs, and we\'re talking
now about sodium chloride, not\--calcium chloride is long gone and was
never there, basically. You\'re always going to have those favorable
nitrate-chloride ratios. But we don\'t see that an aggressive corrosive
brine can develop at all during this above-boiling period basically
based on that.

And so in conclusion, due to lack of seepage, as we\'ve said, the chief
issue is the deliquescent salts. Calcium chloride, magnesium chloride
salts are extremely unlikely to be present as we discussed in the
repository. But in any case, if present, they would rapidly transform to
non-deliquescent phases due to their instability at temperature, at
least as thin dust films here. Any acid gases generated due to salt
deliquescence will be dispersed in the drift atmosphere at environment
and then dissolve into the water in the rock. If condensation of liquid
water occurs accompanied by scavenging of acid gases, it will take place
in the coolest parts of the drift, not in any case on the waste
packages.

Only nitrate-dominant brines will form during the above boiling period
due to the thermodynamics of deliquescence in this particular system.
This is over and above the natural variability of nitrate-chloride
ratios in the dust which as we\'ve shown as quite favorable generally
above .5.

And lastly, the mass of water we\'re talking about here is very, very
small, on the order of microliters. 10s of microliters. And, so that
concludes the main part. This next part is kind of a bonus track on the
Catholic University distillation experiments. Their experiment involved
extensive boiling of calcium magnesium chloride nitrate water and showed
condensation of a low PH water leaving to metal corrosion. I don\'t want
to go into this too much, but the key point I want to ask is this
experiment relative to the drift environment.

And, this is sort of contrasted over on this side, the drift
environment, our conceptual model for it in this experiment. Features of
distillation experiment that do not apply, in our opinion, to the drift
environment at Yucca Mountain. First and most important is the highly
localized condensation due to the closed system behavior of this
experiment. In fact, then later on after they take this part off and add
the Soxhlet cuff, they actually have the refluxing of condensed acids,
and I think Bo gave a pretty good explanation of why we do not expect
refluxing in this heat pipe behavior to occur. In any case would require
a very large quantity of water to humidify the environment. We don\'t
see any evidence for that kind of seepage occurring.

A second point is that their experiments, the corroding metal coupons
are held at lower temperature than the boiling brine. So obviously
they\'d become the locusts of condensations of those acid gases. Well,
the situation in the drift is the waste package is the hottest spot in
the overall environment there, even if you\'re talking about
longitudinal transport down the drift, even then when it gets there,
you\'re still going to find a waste package that\'s hotter than the
surrounding drift wall in other environment.

Another point to be made, perhaps, is that there\'s something inherently
unrealistic about an experiment that involves the equivalent of about
14,000 liters of dilute seepage water in order to conduct that
experiment. There would be very much smaller masses of water that would
even be there, and therefore, the amount of HCL that could be generated
very much smaller. And very large temperature gradients also are not the
same as in the drift environment. This of course is partly what focuses
this condensation all in one spot.

And so, our argument is that the Catholic University distillation
experiment is irrelevant to the drift environment at Yucca Mountain.

DUQUETTE: Thank you. Thank you for being early. Go ahead Ron.

LATANISION: Latanision, Board. If you could go back to the previous
slide where you started with the Catholic, just one I think. Oh,
Latanision, Board. Thank you. Could you go back one. I guess it\'s No.
50 actually. That\'s the one, yeah.

I take your point in terms of the conversation regarding Catholic
University experiments that you\'re asking is the experiment relevant to
the drifts environment. And, I think I would have to ask the same
question. Of the tests that have been done by both the project and by
CNWRA on magnesium and calcium chloride brines, why are those
experiments relevant? Why have we seen so much data? You may not be the
right person to answer this question.

STEEFEL: No, I\--maybe somebody else can answer. Are you referring to
the corrosion tests?

LATANISION: Yes.

STEEFEL: Involving liquid, or are you talking about the TGA now?

LATANISION: No, I\'m talking about the tests that have been performed in
concentrated brines over the, you know, this is the data that led to our
concern in terms of the Board\'s expression, both in terms of the letter
and the report, so I\'m just trying to put in perspective, given all
that you\'ve told us, if magnesium and calcium chloride dust is not
likely to be present, what was the point of all that experimentation?

STEEFEL: I\'ll let Greg answer that. I could give an answer, but\--

GDOWSKI: I think we have been evolving in what we\--

DUQUETTE: Please identify yourself for the record.

GDOWSKI: I\'m sorry. Greg Gdowski, Lawrence Livermore. I believe that we
are evolving into what we believe that the environment is and now that
we\'re getting a better characterization of the environment, the systems
that we were testing at one time don\'t seem as relevant.

STEEFEL: Obviously, the sodium chloride and things like that are still
relevant because the\--

LATANISION: Latanision, Board. That would be my second comment. If we
could go back to, one of your slides shows that transient\--temperature
time transient\--I\'m not sure which number it is.

STEEFEL: Do you mean way in the beginning or\--

LATANISION: Yeah, way in the beginning. What I\'m interested in is\--

STEEFEL: Probably about 7 or 8, or\--

LATANISION: What I\'m interested in is having a sense of over what
temperature range we will get back and what time period you would expect
sodium chloride or the eutectic mix of sodium\--of chlorides, nitrates
to be present.

STEEFEL: One more there. Can we go back\--

LATANISION: Yeah, that\'s probably it.

STEEFEL: Okay, that\'s good. The\--

LATANISION: Didn\'t have a number. That\'s why I was confused.

STEEFEL: Sodium chloride would be in the high temperature period, of
course. The second talk focuses much more on that issue. Sodium chloride
in the below-boiling period and that\'s probably the key player there.
But in the above-boiling period, it\'s basically at these low RHs,
sodium chloride can be totally dry, so it\'s basically only when you get
the deliquescence point of that mixture of those nitrate and sodium
chloride salts that the RH that\'s going to come into play, I forget
exactly where that is, but that\'s going to be somewhere I think about
55 percent. So you\'re really talking about this period from about right
there, I think, up to about there, during the above-boiling period. And
it might have shown that on that very last slide towards the end that
you\'re talking\--

LATANISION: That\'s right.

STEEFEL: That period of course then the thermodynamics are giving you
back high nitrate to chloride ratios, which are going to be well above
the actual sort of point where you get significant corrosion occurring.

LATANISION: Latanision, Board. That\'s roughly what I thought in having
listened to your comments. So the corollary question then is the project
planning to do tests in those environments which I think we\'re now
coming to a sense of are important. Are you planning to do tests\--

GDOWSKI: Greg Gdowski. We have done the tests and Joe Payer will present
them later this afternoon.

LATANISION: Great. Thank you.

DUQUETTE: Dan Bullen?

BULLEN: Bullen, Board. Could we go to slide 21, please? The bottom point
says that the remainder of the four percent don\'t satisfy this
condition. The first condition was that the dust fails to satisfy
condition 1. Is there a heterogeneity in the dust throughout the
repository and so do you get variations in the types of dust, or is this
just a conglomeration that all the dust, you know, doesn\'t meet this 96
percent requirement?

STEEFEL: I\'ll let Tom Wolery, he\'s done the most work on that. He\'s
got a whole MR on that.

WOLERY: Okay, the data referred to here again from the tunnel dust,
leachates, and basically these are processed through EQ3/6 calculations
simulating evaporation. We then looked at all of the salt minerals that
were predicted to form in these, and then tried to sort these things out
in terms of what would control, for example, the initial deliquescence,
and that kind of focused us on sodium chloride plus potassium nitrate
for about 66 percent of the cases. For most of the remainder of the
cases, the same assemblage plus sodium nitrate, and then in a very small
number, range, four percent basically those ended up coming up also with
calcium nitrate. And we never saw any calcium chloride come up in these
calculations, but we do see a calcium nitrate.

STEEFEL: That was true in all of the dusts you looked at so this
includes how many samples did you have? 38 or 50?

WOLERY: There\'s something like, depending on how you count them, about
50 some samples.

BULLEN: Bullen, Board. Were these samples\--I know that they were taken
at various parts of the repository. Could you tie the sample to the type
of geologic strata that you were in? Is there a different characteristic
of the dust in the lower lith versus the middle non-lith, versus the
upper lith?

WOLERY: I can\'t really answer that question, but I don\'t think so.

BULLEN: Bullen, Board. Do you think that\'s just because the dust was
ubiquitous or because there is no difference between those two, or those
three strata?

WOLERY: There may be, but, you know, I might defer some of the answer to
that question to Zell Peterman who actually took and analyzed the
samples, but I know that a big part of the answer is we know that most
of the dust in the tunnels is actually rock dust. That contributes
particularly strongly to overall composition, but particularly the
insoluble composition, but anyway, Zell, do you want to take it from
there?

PETERMAN: Yeah, there\'s a lot of variability\--

DUQUETTE: Please identify yourself.

(The comments from Zell Peterman were made away from the microphone. The
following is the audible portion of that comment:)

PETERMAN: Zell Peterman, USGS. There\'s a lot of variability in the
overall dust composition (inaudible) elements and traces. Some of it
seems to be related to how close you want to (inaudible). So there\'s
probably a component of experiments of film dust coming in there. Within
the main, the lith main drift (inaudible) and the rock (inaudible).
(Inaudible) and the total (inaudible). No significant gradient of
(inaudible) within all the different zones, the lithophysal or
non-lithophysal zones. So that component which is, you know, 98-plus
percent of the dust is (inaudible) composition.

BULLEN: Thank you, Zell. Bullen, Board. I just had a couple more
questions. Can we go to slide 38, quickly. I was very intrigued by
interpretation of where the acid gas is going to condense and how it
would be diluted, except where I see in your model is that you\'re
missing some structure here. You\'re missing the drip shield, you\'re
missing the internal construction components of the ground support and
so the question that I have is, if there were condensation under the
drip shield, would you expect the acid gas to then be focused to an area
where there may actually be, and again, variability, along the drift and
may end up with a cool spot where I\'ve got condensation under the drip
shield and so instead of getting the acid out into the rock, I produce
the acid solution even in my new quantities at the surface of the drip
shield and actually either cause failure to the drip shield or failure
to the waste package because what I\'ve done is essentially concentrate
all the acid gas into the area that is systemic. I have a perspective as
to why I ask this question. Years ago, Rich Attebury at Livemore took a
look at radiolysis effects and found that the nitrates that were
produced in accelerator environments ended up on condensate water on
copper piping and corroded the daylights out of it. And so, this
condensation of gas is actually a key issue that if you are actually
making it and it condenses in the wrong place, not in the rock, but on
the drip shield, could that pose a problem?

STEEFEL: I think that, first of all, of course, that we expect if
there\'s any volatilization it\'s going to occur at the highest
temperatures when the drip shield would be well above the boiling point
so condensation isn\'t going to occur. But just to follow this scenario
out, it\'s true then that first of all that the drift wall is still
going to be a lower temperature than the drip shield. So if that gas can
get out it\'s basically going to migrate out to that zone condensed air
and then work its way into the water actually held within the rock mass.
Now, if you had a tight, for example, a tight drip shield, then you\'re
going to have to rely on basically longitudinal drip transport to go
down through the system and get out of the system there, but again, the
drip shield is really not, you know the design is a quantitative thing
that\'s going to capture anything there. It\'s still going to move
longitudinally along the axis of the drift and of course,
that\'s\--isn\'t actually shown there.

BULLEN: Bullen, Board. Just one last quick question. Do you produce acid
gas above the boiling point?

STEEFEL: Of what? Boiling point?

BULLEN: At the repository horizon. Do you produce the acid gas about
that?

STEEFEL: What do you mean above\--you\'re talking about the TGA, you
see, you don\'t see it at 100 degrees. You see it at 125, so it\'s only
the deliquescing ones there.

BULLEN: Bullen, Board. Then one would ask the question, why would one
want to go above the boiling point?

STEEFEL: Because you\'ve rendered these\--you\'ve rendered all these
slats benign by getting rid of the HCL.

DUQUETTE: Let me take the Chair\'s prerogative for a minute and say, and
pick up on a theme that Ron Latanision picked up on this morning. You
indicated that the water is not going to get in there through seepage,
it\'s not going to be stable for corrosion processes on the canister
wall. Why on earth do you need the drip shields?

STEEFEL: Yeah, that came up before. The drip shield really plays a role
in the lower boiling period. And you\'ll see when I get into that why
the drip shield is useful. I\'m not sure that you need it during this
stage at all.

DUQUETTE: Terry, you have a question?

CERLING: Yeah, I have a couple of questions. One\--Cerling, Board. One
question, you\'ve showed us how hydrochloric acid is generated in this.
In any of your work with the nitrate compound, did you ever get any
generation of nitric acid?

STEEFEL: Yeah, I\'ll let Greg\--Greg has done\--

GDOWSKI: Greg Gdowski, Lawrence Livermore. We\'ve only done a few
experiments with mixtures of chloride and nitrate. And, calcium chloride
is actually less deliquescent than calcium chloride, so what we saw
while we were\--

CERLING: Nitrate. Nitrate.

STEEFEL: Calcium nitrate.

GDOWSKI: \--is less deliquescent in calcium chloride. So what we saw was
when we evolved the ACL gas from that mixed solution, we saw
precipitation of calcium nitrate and this insoluble calcium hydroxic
chloride. We haven\'t actually done it at higher RHs. But it might still
remain soluble with the calcium nitrate.

CERLING: And then, if we could drag Zell Peterman back. The question
that I wanted to follow up on was the one earlier about the
inhomogeneity of the salts and obviously one of the sources of salts is
whatever construction activity there is, and the other has to do with
whatever is really contributed by the rock. And so, I was wondering if
in your collection of dust samples if in areas where seepage was more
likely to be involved in the contribution, is there a difference in the
chemistry that you could attribute to sort of the rock end member versus
the anthropogenic end member, and\--

PETERMAN: Zell Peterman, USGS. No, we haven\'t seen that. The, you know,
if we use the calcite (inaudible). Okay, is that better?

The area where we would see the greatest seepage was is under
the\--under drill hole (inaudible). That\'s where the greatest abundance
of calcite deposits occurred. No, we did not see any corresponding
variation in the dust, and I guess what I\'m hearing was once you\'re in
the main drift and then, you know, ventilation system, things getting
pretty well mixed up, that\'s sort of the goal when they are collecting
dust and raising dust and they see it dispersed and moving down, you
know, mixing, and you can see that. The other component, well, we think
the components are construction water. We can tell that by looking at
the bromine, by natural pore water salt that form on the tunnel walls
and then there\'s, you know, other things, like ground\--conveyor belt.
You can see a lot of black specks, which are carbon. I\'m sure
(inaudible) lot of different components, but once you get away from the
North Portal, things are relatively intertwined. The dust composition.
Both the solubles and the (inaudible) both dust compositions. I don\'t
know if I answered, responded to your question properly.

CERLING: Pretty close. I guess following on that, do you think that you
could come up with perhaps a few and perhaps only one, sort of end
member composition that is contributed by the natural system? Is that
possible? Or how many dust samples would it take to be able to calculate
that end member value?

PETERMAN: No, I think we can. The silica rhyolites predominant rock in
the tunnel and whether it\'s the Topopahans that got a little bit riled
at it, at the T results of that rhyolite. Now, at the upper part of each
of those units there\'s of course latite, and that has a different
composition than the rhyolite. Some key elements, you know. It\'s higher
than titanium, higher and higher. It\'s still got, you know, 73, 72
percent SiO2 compared to a 76 percent for the rhyolite. So it\'s not a
really big difference, but we can pick those sort of things up. Because
our paper, I think it was the high-level waste last Spring, a year ago,
and just, you know, using these prior diagrams could compare with things
you can see what\'s enriched in the dust relative to say the rhyolite.

CERLING: Yeah, I was thinking mainly in terms of the soluble component.
Cerling, Board. I think thinking more of the soluble component rather
than the insoluble\--silica and so on.

PETERMAN: Okay. As I say, it\'s sort of a random\--in the soluble
there\'s sort of a random variation. Once you get away from the
immediate effects of the North Portal.

CERLING: Okay. Thanks. I\'ve got one follow-on because I can\'t resist.
I have to ask a Bullen-Board question. So this is Cerling, Board asking
a Bullen, Board question.

From your slide 6, you might be able to make the argument that perhaps a
higher temperature is actually better in terms of the corrosion issue
because it gives you sort of a protective period, So in asking that I
would say ask the anti-Bullen, Board question. Is a higher temperature
design in this particular corrosion question, is it actually better than
a low temperature design?

STEEFEL: The only reason I\--I mean you said that was a nice try, but
the only reason I agree with you on that was that I don\'t expect
calcium chloride and magnesium chloride salts to be there. So that
volatization issue is probably a non-issue from the beginning. But the
additional benefit, of course, is that extended vaporization period
where you have nitrate and chloride ratios at favorable. In any case, I
don\'t see big objections to it. It seems like these issues, they don\'t
make it worse. You may not get a big benefit out of it.

PARIZEK: Parizek, Board. On the amount of acid that, gases that could be
produced, I didn\'t get a sense of volumes or whatever, but if it heads
for the wall early in the placement of waste packages, it sees pore
water and ends good. It disappears in there. What does that do to the
chemistry of that water? Does that chew away on the rocks and so, you
know, we heard from Bo how nice the water chemistry could be, but is it
likely to become normalized if in fact acid is produced or how much acid
is it? I mean it\'s going to get neutralized, as you pointed out, but\--

STEEFEL: I mean obviously, somebody could go out and design an
experiment where they took, you know, huge quantities of HCL and
dissolved small amounts of rock and you could then produce a very
concentrated. The issue is that you\'re talking about a small amount of
HCL that have been dissolved in a fair amount of water with even more
rock out there. And then basically the scenario I think is, as Don
Langmuir described yesterday, at that stage the HCL becomes a dilute,
fairly dilute weak acid that reacts with just like weathering with the
minerals and the rock. And then there\'s more than enough of that
material there to buffer the PH and bring it out. When we actually did
those earlier ones, all we did was take the HCL and put it into the
water. Even there we saw only a shift of PH of a few hints, you know, to
have the PH in something like that. You\'re talking about small amounts
that the natural system shouldn\'t have any problem dealing with, but I
don\'t know if, Eric, you want any comments to add to that. He has
worked on the drip scale and the whole business of the reactivity of the
system and\--

SONNENTHAL: Eric Sonnenthal, Lawrence Berkeley Lab. Yes, actually, the
PH shift is virtually not noticeable in this case. The heating of the
flow waters that\'s coming down to the drift is actually devolatizing
CO2 and increasing the PH slightly in those figures and so you can\'t
even see the PH shift of the HCL. You have so much rock area where that
gas is going through fractures and is dissolving the rock, there
probably are some shifts in the reactions, but it\'s going to be not too
noticeable.

PARIZEK: Thank you. That\'s trivial, sounds like, then. And, the other
question about the Catholic University, all their making is to create
things other than dust and that\'s dripping water, which then evaporates
and leaves some scale on the waste packages. Now really, in the
placement of the waste package underground before boiling temperatures
occur in the rock wall, you\'ve got a lot of water in there, and now you
could have dripping because of this redistribution of moisture in that
short time period. You folks discount then this dripping water and the
possibility of developing scale, as we heard yesterday from Catholic
University?

STEEFEL: This is during the heat-up period?

PARIZEK: Right. Just early in the heat-up period. I mean you\'re getting
into the point where you don\'t get half this boiling rock vapor barrier
thing that both says will exist that you need very protected. But to get
to that point you\'ve got water in rock early on.

STEEFEL: Bo could answer that, but I mean the capillary barrier is still
in place there, so you\'re, you know, and you\'re talking about the
present regime with low, you know, the climate is such that the most
we\'re getting basically for waste package in the extreme case would be
about, you know, a kilogram of water or something per year. And that
doesn\'t even take into account the small percentage that\'s going to
actually seep, which is somewhere, forget what it was, three to five
percent. So you still have a capillary barrier.

Secondly, is that, you know, you\'re not going to get those concentrated
brines then. You\'re talking about before heat-up. You\'re basically
going to heat up that drift wall within, say a few years, assuming the
waste packages are hot so you\'ve got a very limited time to do any
seepage, and actually evaporate something on the surface of the package.

PARIZEK: Parizek, Board. Again, if we look at the heater, big block
heater experiment rather, there was free water outside of the shielding,
but you couldn\'t go in after the experiment mode so you could get water
because it seems to be possible, really, in these experiments. So even
though you have a capillary barrier, you still had free water in at
least two locations of the experiments that we saw in the field.

SONNENTHAL: Eric Sonnenthal, Lawrence Berkeley Lab.

We only saw water out in those backed-off hydrology boreholes when the
temperature was very close to boiling and the vapor, the water mass
fraction in the gas is extremely high. So you have a very short period
of time way out in the rock, and that\'s the only time we ever collected
water and it was only out in the rock.

PARIZEK: Parizek, Board. Was there not water on the floor just entering
up to look into the gauge of whatever that heater experiment was
conducted before?

SONNENTHAL: Not in the drift. We\'ve only seen water that condensed on
the outside of the bulkhead.

PARIZEK: That\'s the water I have in mind. The bulkhead was not totally
sealed.

SONNENTHAL: Right. In the drift we\'ve never found water.

BODVARSSON: Bo Bodvarsson, Livermore Berkeley Lab. Just to clarify,
that\'s water outside which is condensation of steam that went through
the bulkhead. So it had nothing to do with, really, the canister of
water or seepage.

ABKOWITZ: Abkowitz, Board. I\'d like to take this discussion to new
heights, namely 50,000 feet since I\'m not a member of the Yucca
Mountain underground, but I do think I can contribute at that level.

What I think is that we have a situation here where corrosion has been
expressed as a concern by the Board for quite some time, more than 10
years. It has survived many different transitions and board members and
different political administrations and so forth. And, the Board has
been sending a message for a while that this is a concern and it sort of
put an exclamation point on that message last Fall. What I had
subsequently heard from the conversation today is that the environment
under which tests have been conducted for many years, expending many
millions of dollars, is not an environment that\'s plausible. And that
this is something that has just been learned over the last few months
and is being presented to us today, and so basically the concerns of the
Board are, in DOE\'s eyes, a non-starter.

As someone who has kind of, at least for this Board, a mantra of taking
the time to do things right, it seems to me that this new information
and new conclusions is a, you know, rather sudden set of
accomplishments, and the project at this complex, when that pace of
learning is occurring at such a high rate, it tells me there\'s probably
a whole lot more learning that needs to go on in this area or other
areas. And so, I want to, you know, I want to go on the record as
expressing a concern that if we\'re still learning these types of things
at this point in time, you know, I wonder whether or not we should be at
a point where the repository design is always so well defined and ready
to go. So I just express that concern and I invite anyone from the
agency to respond.

ANDREWS: Yeah, this is Bob Andrews. Let me try to respond a little bit.
It is true that some of the testing from corrosion perspective was
initially conducted in calcium chloride type brines with varying amounts
of nitrate. You\'ll see some recent data collected over the last six to
nine month in sodium chloride type brines and other brines including
sulfate\--in fact, I don\'t think we\'re going to show the sulfate data
this afternoon. You saw some sulfate data yesterday from NRC. So the
testing, types of environments tested, the range of temperatures and
range of chemistries has evolved in continuing testing of a range of
environments.

However, I think the point we\'re trying to make, especially in Carl\'s
talk, is the Board put some pieces of information together based on the
presentations last May that were in fact in correct. That although we do
observe calcium and we do observe chloride, we don\'t observe calcium
chloride in the dusts, in the salts, present at Yucca Mountain. There\'s
no evidence for that. In fact, even if it were present somewhere in the
southwest, and there have been sporadic, I think as Carl pointed out,
observances of calcium chloride dusts in the High Sierras, I believe.
They are not stable.

So, for those two reasons alone, let alone going to the volatilization
at higher temperatures, the Board\'s premise in their November 25th
report is not correct. You know, we apologize for the Board having come
to that conclusion, but it was based on information, I guess the Board
put together and the fact that we did not, as I said in my introduction,
talk specifically about what were in those salts when we presented the
information last May. That is recent information. You\'re absolutely
correct. So, yeah, you\'re right. The Board had some inferences derived
from some information, not the complete story, and we\'re trying to
provide that complete story today.

ARTHUR: Also, John Arthur, Department of Energy, and I must respond
also. I think if anything, many of the comments which you suggested are
made by previous boards, but if anything, I think we try to be
responsive to the letter and present our case today which is many of us
tried to do. As far as the issue raised about designs (inaudible) we\'ve
been continuing to (inaudible) of this design and I feel it is optimized
now. I feel that a self-service (inaudible) presented yesterday. We\'re
making very good progress and we have something (inaudible) to the
Regulatory Commission. And the ball is in our Court, so I (inaudible)
come up with \--set of science today.

PAYER: All right, Joe Payer. (Inaudible) the other end of that and that
is the corrosion strategy throughout the years as somebody who has been
involved in peer panels a little bit, DOE has worked in this area over a
number of years. And over the last year and a half, had the charge from
the director to look at the corrosion program strategy and the way it\'s
laid out. A basic foundation of that strategy is to identify the types
of environments that may pertain at Yucca Mountain and those that won\'t
pertain at Yucca Mountain. And that has been the focus of Carl\'s first
talk here, and we\'ll continue after lunch.

The other basic premise is to identify the corrosion behavior of Alloy
22 in a range of environments so you\'re trying to match the realistic
environments to the realistic corrosion behavior, and you want to go
beyond that. The project has chosen not to go as far beyond that as the
State of Nevada into boiling barite chloride and some other elements
that we believe just don\'t need to be tested, but you know, to look at
the calcium chloride environments is very relevant because some of you
have asked and others as well, well, maybe we don\'t believe, or what if
something happens where both\--what would happen if Alloy 22 was exposed
to these environments? That\'s why we\'re doing the tests, and we\'ll
talk about that later this afternoon.

So, the other part of it is that Carl\'s talk here is talk when the
thermal barrier is still in place and this afternoon he\'ll talk about
when we can have dripping and seepage conditions. And that\'s a whole
different ball game at that point. And so, the corrosion becomes more of
an issue, we believe, in that case.

SHETTEL: Don Shettel from the State of Nevada. I have several comments.
I had a comment on the drip shield, but I think I can drop that now.

Sepiolite, we would agree that in certain environments, certainly you
can get magnesium removal, such as seawater running through Ocean Ridge,
the salts. But the environment at Yucca Mountain is totally different.

Regarding HCL, this also has something to do with the drip shield. But
if you recall one of my last slides where I had the C-22 in the boiling
HCL, and we got the part that was exposed above the liquid was almost
totally gone. Now, I believe if the HCL is being\--is reacting with the
C-22, we\'re not talking about diffusing way off into wall rots. It\'s
reacting right next to where it\'s boiling and that\'s the chemical sink
for it, doesn\'t have to diffuse away from the canister, and doesn\'t
require cooler temperatures or anything else.

Regarding the comments on the Catholic University experiments, I think
Dr. Staley covered the similarities there between the experiments and
the drift. I also want to say that we don\'t have to concentrate these
waters before they hit the drift. I mean the canisters. They have
experimented. We started out, certainly, with concentrated experiments
and some other things like lead, but recent experiments were very,
starting with very low and essentially 1X pore water. It is possible to
get corrosion with just 1X pore water, so these large quantities of
water that you\'re referring to are not necessarily required. And, I
think one of the main differences between what you\'re talking about,
which is deliquescence of dust without any addition of seepage water and
what we\'re considering, which is the possibility of getting seepage
water through the so-called vaporization barrier during the thermal
pulse is very likely because you have episodic flow of water and pulse
in fractures and therefore it is a possibility. We\'re not saying that
everywhere you get this, unlike what you are saying that everywhere you
have very dilutant benign waters.

I think that\'s all unless you want to make a comment.

STEEFEL: Let\'s see what would be\--oh, the one on sepiolite, I don\'t
have much to say there. I mean at Mid-Ocean Ridge at Marvin was just
thrown out as an example, but it\'s actually precipitation of magnesium
silicate he has observed in the\--

SHETTEL: Oh, yeah, yeah. I want to comment on that. The precipitation of
magnesium and other clays, for instance, require aluminum and you really
don\'t have much of that in the unsaturated zone pore water that\'s at
other repository levels. So without aluminum, you really are quite
limited in magnesium removal methods there.

STEEFEL: Yeah, that\'s required in the\--but I am still not convinced
that there\'s no sepiolite developed because if you\'ve got aluminum
that\'s presumably why, one of the reasons why sepiolite didn\'t form.
Just simply you had a more stable magnesium clay you could form with an
abundance of aluminum present in solution. So\--

SHETTEL: It still has to be shown experimentally other than just
modeling that you can get such a phase.

STEEFEL: If it\'s observed in other, you know, I\'ve seen it\--I
haven\'t done a thorough literature search, but I\'m certainly seen it
in the opalinus clay experiments where sepiolite was identified via
x-ray. Now, that\'s a hyper alkaline.

SHETTEL: I was going to say, how relevant is that to Yucca Mountain?

STEEFEL: It might be and might not be. But you\'re saying that it has
never been observed, so\-- And what was your second thing?

SHETTEL: Also, Gdowski, you did find some magnesium smectite in his
experiments.

STEEFEL: Well, that\'s similar to the magnesium clay that\'s found by
Carroll and Gdowski.

SHETTEL: That was an experiment that had tuff added to it. We\'re
talking about the evaporation of pore water\--

DUQUETTE: I\'m going to have to\--you know, if we\'re going to have any
lunch at all, I have to stop this discussion. Now, there will be more
time for discussion later on. I\'m going to take two quick questions,
one from my colleague, Dr. Latanision and the other from Carl DiBella.

LATANISION: Carl, you want to go first? Go ahead.

DIBELLA: Could I have your conclusion slide again? And I\'m going to try
to be very quick. You had two conclusion slides. This is Carl Dibella,
Board Staff.

And maybe the second one first and I\'m going to try to work backwards,
very quickly through them. It\'s like No. 42 or 43. No, it wasn\'t that.
Okay, let\'s do the next one, we\'ll just work backwards. Can I have the
next slide, please, 49. I\'m going to work backwards.

The mass of H2O taken up in the salts is very small. I think everyone
knows this. I would hope maybe when Joe talks this can be translated
into, if there is corrosion, how many holes or what\'s the size of the
holes or how deep are the holes or something of that sort, what\'s the
relevance of that? We tried to, at least I tried to, think of what is
the lower limit of corrosive material that would not be of concern, and
I don\'t know what it is, but maybe the project does. So maybe Joe can
do that.

Working backwards, this conclusion is, a conclusion I think is we can
all agree with. But it\'s for a very different system than the system
that the Board was concerned about and it\'s paper. The system the Board
was concerned about was the calcium magnesium chloride deliquescence.
This is sodium, potassium chloride, nitrate deliquescence that is simply
another issue. And furthermore, as you showed, the sodium nitrate has a
much lower deliquescence point than sodium chloride and so its behavior
is nothing like the calcium chloride, calcium nitrate, magnesium
chloride, magnesium nitrate systems. So I don\'t see the relevance of
that conclusion to the Board\'s paper of last Fall.

Could we move backwards again? One slide backwards, 48. Condensation,
scavenging of acid gases absolutely will take place in the coolest parts
of the drift, not the waste packages. But that\'s not an issue that the
Board brought up in its paper. We are not suggesting that the acid gas
reacts with the paper, with the package in the paper. We\'re suggesting
that the acid gas needs to be removed in order for\--if the acid gas is
not removed the calcium chloride stays where. That\'s simple
thermodynamics. And, if the calcium chloride stays there, the project
has shown us data that there is corrosion. So the question is does it
stay there? The data shown to the Board which we put up yesterday with a
thermogravimetric experience, experiments, where the hydrogen chloride
was swept away by the movement of gas through the system. And therefore,
it had to be continually replenished by decomposition of calcium
chloride. If it\'s not swept away, of course, the calcium chloride stays
there. So the question in the Board\'s paper was, please show us how the
system, the condition in the hydro\--thermogravimetric apparatus are the
same as the conditions in the repository?

STEEFEL: Another aspect of the thermogravimetric apparatus is that it
was actually operated in a relative humidity above the deliquescence
relative humidity so it was forcing the reaction to the right with that
point of view also, so there may well be an explanation. But we haven\'t
received it to date. The acid gas will disperse. There\'s no question.

DIBELLA: The question is how fast does that happen? If we\'re going to
disperse by the convective forces in the repository, how do they relate
to the thermogravimetric apparatus, number one. They are going to
disperse by plain old ordinary diffusion. How fast is that going to be?
If it\'s very rapid, fine, if it\'s not rapid, we might have a problem.

STEEFEL: I\'m not sure I didn\'t show that. That was the point of those
simulations obviously. Those were preliminary in nature, but they
basically showed the dispersal of that HCL gas in the drift environment
using the model that\'s been used to describe gas migration, obviously
focused on CO2 in the mountain and in all the drift scale tests. So if
it, you know, I didn\'t present a detailed one-for-one table, but
there\'s certainly some presentation of the transport of HCL away from
that waste package.

DiBELLA: That kind of thing was fine. I think it was 120 degrees
and\--but that sort of simulation is a very good idea and I did notice
that the time frame for dispersion was much higher, much more time is
required than the gravimetric experiments. It only took like 20 hours.

Let\'s see, Point No. 2, the rapidly transformed and non-deliquescent
phases, do they\--yes, they are unstable, but again you have to remove
the HCL where they become stable. And, how fast does the HCL move is a
real question.

Now I get to your first point which was are the salts there in the first
place? And I certainly think if they are not there, we don\'t have an
issue. And so it\'s very worthwhile looking at this, but the technique
you\'re using of dissolving the salts and then re-evaporating them
assumes equilibrium of the salts, and one has to say, why equilibrium is
a good assumption. And I could make an argument for why it might be a
good assumption. If those salts had been exposed to a lot of rainfall
before they came into the repository, fine, but you didn\'t make that
argument.

STEEFEL: And that\'s\--can I make a comment? That\'s where in that
switching skipped over that slide. Can I go to about slide 24?

DeBILLA; It is 24 and you very specifically mentioned disequilibrium as
being a possibility.

STEEFEL: Yeah, so that\--no, I skipped over this. The point here was
that, yes, you could have, if these things blew in from somewhere, they
would initially be expected to be a mechanical mixture with no aqueous
phase there. The argument here is that, as soon as initial deliquescence
occurs, you\'re basically going to expect to get a transformation, for
example, via some reaction like this one, calcium chloride plus the
sodium sulfate goes to a more stable phase. The experiments that have
been done so far indicate quite rapid action time so there doesn\'t seem
to be a huge kinetic barrier. And secondly, the reaction products have a
higher deliquescence RH and that\'s what causes them to dry out. But
this is the argument, the secondary argument has to do with transport
from any particular site or\--

DIBELLA: That didn\'t seem to be one of your conclusions, but
nevertheless, we\'re probably\--the thermodynamics, I absolutely agree
with. But the\--we\'re dealing with solution of calcium chloride, more
like calcium chloride in other stuff that is completely saturated
thermodynamically. How is that reaction going to, all those things going
to get together for that reaction to take place? If they do get together
I agree the reaction will take place. And, you need to explain that.

Now, one last thing and that is that we didn\'t have the data, although
the data were available, we didn\'t have the data on the composition.
Well, the data weren\'t available. This is new data for me on the
composition of the salts. But we did have one key piece of data and that
is this experiment that was done largely in our laboratory on pore
water. It was a synthetic pore water, but it was based on measured pore
water where they evaporated it, not in the presents of tuff, and came up
with tachyhidrite. Yes. That\'s a calcium, magnesium, chloride salt.
That is very worrisome. You can\'t\--you didn\'t mention that piece of
data. Is it raw? Is that maybe only one percent of the pore water, did
they not put the synthetic pore water together correctly? I don\'t know
what the answer might be, but if that\--that\'s a piece of data that
just can\'t be important.

STEEFEL: Well, that was evaporation experiments of the subject of the
second talk, but maybe\--Greg, can you comment on\--

GDOWSKI: Eric has a comment.

SONNENTHAL: Eric Sonnenthal, Lawrence Berkeley Lab. I think that one
pore water that Rosenberg et al paper used was not an actual pore water
composition. There were several values in that report, and that happened
to be just a hypothetical case. So more in the middle of the report.
It\'s unlike other compositions.

DiBELLA: It was based on measured pore water. Absolutely. Now, whether
it was based properly on measured pore water\--

STEEFEL: My understanding was that it was something of a synthetic pore
water, but that there were some general samples, not from the repository
horizon, but above the repository horizon that had that general
signature. I don\'t remember exactly what, for example, silica
concentration they used there. It\'s still\--there\'s still a question,
given such, you know, evaporation experiment that you can often form
transient phases that may not be applicable over the somewhat longer
time frame of interest in terms of corrosion. I mean that\'s the
argument. Any time you apply an equilibrium analysis, it assumes some
time frame and so the question is is that evaporation experiment the
same as the relevant time frame within the drift environment, which
normally I would expect to be longer. So, that would be my main point
about that.

PYE: Pye, Board staff. It\'s our recommendation of the Board\--excuse me
the project showed that in the in-drift environment the drip shield and
the invert coupled very closely. Indicia cited for condensation under
the drip shield was the drip shield was cooler than the invert and that
condition seemed to be fairly prevalent. I guess my question is, since
I\'ve looked at slide 38, the other piece of the EBS that\'s missing is
the invert. So my question is, what recent assessments have been made to
assess the potential floor condensation in the in-drift environment on
the wall, on the drip shield and the waste package and is there an AMR
you could direct us to?

STEEFEL: I can\'t do that, but maybe Eric can.

SONNENTHAL: Eric Sonnenthal, LBL. Regarding the first part of your
question, we\'re plotting here the PH in the water phase. There actually
is an invert in this model. But it\'s\--you can actually see part of it
is wet, down below. I think I have to leave the second part of the
question\--I\'ll take that\--

ANDREWS: Yeah, John, this is Bob Andrews, BSC. There are three AMRs in
fact that hit various elements of condensation and convection in the
drift. One specifically is devoted totally to that subject called
In-Drift Convection and Condensation Model and Analyses. Two other AMRs
hit on it. The Thermal Seepage AMR and the Thermalhydrology AMR discuss
the concepts of lateral flow and invection down the drift, but the
actual results being used are from the first one I mentioned. In-Drift
Convection and Condensation Model. As I said at the very beginning, we
didn\'t think we had adequate time today to go into the details in the
in-drift convection and condensation. It is being included in the total
system performance assessment, and we\'ll be happy to talk about that
next time.

DUQUETTE: I\'m going to cut the meeting off here since we\'re well into
the lunch hour. Let\'s convene in exactly an hour.

(Whereupon, the luncheon recess was taken.)

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LATANISION: Let\'s take our seats, please. We have a pretty full
afternoon, and so if everyone could be seated.

When we began yesterday, I made the comment that I had as a personal
goal providing an opportunity for a full and objective hearing of the
concerns that the Board had expressed regarding the Project\'s corrosion
studies. And I want to thank everybody who\'s been a part of the
conversations over this past day from the State of Nevada, from EPRI,
from the NRC. I think\--and, of course, from the Project. I think we\'ve
had that kind of conversation. I\'m really very pleased by that. So, I
do want to thank everyone for the spirit in which we\'ve had these
conversations during the past day. And I hope that we\'ll continue this
afternoon.

We have two speakers. We\'ll continue with Carl Steefel who will talk
about thermal chemistry and evaporative concentration evolution, and
then we\'ll hear from Joe Payer. Carl?

STEEFEL: So, hopefully this talk will be a natural follow-on to the
preceding one. We might even revisit some of these issues. But, as I
say, as I said in the beginning, I think there\'s a natural division
between some of the issues during the below-boiling period and the
above-boiling period. Can we get the next slide, please?

The acknowledgements here, a similar cast of characters with talk
preparation by Dave Sassani, Nic Spycher; the pore waters, Zell Peterman
and Nic Spycher at Berkeley Lab; in-drift chemical environment, the same
cast we had earlier; and then at least some discussion of the THC
evolution where Nic Spycher and Eric Sonnenthal gave me some help. I
don\'t know if Eric is still here. He had to\--well, we\'ll see. If we
could get the next slide?

I want to start with some of the Board\'s comments on seepage chemistry
that provides some motivation partly for what I\'m going to talk about.
They said the DOE\'s analyses of water chemistries and their corrosive
potential are extremely complex and suffer from empirical and
theoretical weaknesses. Thus, the Board does not have a high degree of
confidence in DOE\'s conclusion that any seepage water would be dilute
or noncorrosive. This is from the Executive Summary.

And in response to the Board, we are presenting here an overview of the
processes affecting seepage water and evaporated brine chemistry and
provide a high-level description of how these processes are addressed. I
don\'t think I\'m going to be able to explain everything of what\'s done
there, but hopefully enough to get people started so if they want to
pursue the issues, they can actually go to the individual technical
documents. Next slide, please.

And so, as an overview, a brief definition of the below-boiling period.
What processes then we want to consider, what processes affect the
chemistry of solutions that could contact the waste package, and what
are the sum total of processes? One of these is what the natural
variability of ambient pore fluid compositions is and how will this
variability affect in-drift chemistry. And another important question to
be considered, how does the thermal-hydrologic-chemical evolution, we
call that the THC evolution, affect the composition of potential seepage
water? And, lastly and importantly, how does evaporation in the drift
affect the chemistry of solutions that could contact the waste package?

And then we want to kind of, at least, make a preliminary attempt at
rolling all this up and say something about then how this chemistry,
which we\'re going to be talking about here, is coupled to the
Time-Temperature-RH histories of the emplacement drift. So, we start to
get an image then of how chemistry seen by a particular waste package
evolves through time and have some conclusions at the end. Next slide,
please.

And, of course, the purpose here in evaluating the chemical evolution of
fluids is that aqueous solution types affect Alloy 22 waste package
corrosion differently. This is a kind of bubble diagram you might have
seen before with decreasing RH, increasing evaporation this direction.
You start with some kind of dilute water, obviously, and depending on
what kind of reactions take place, concentration mechanisms, you can
form different kinds of brines. And, of course, these brines will have
very different affects on the corrosion of the waste package. So,
that\'s why we need to look at this issue. Next slide.

Before I go on, though, I want to make one point about in which cases
will the chemistry of seepage water be relevant. This is really a
perspective slide here. Say the chemistry\'s really only going to be
relevant when seepage can occur. Seepage can only occur when the drip
shield fails. And even in the absence of a drip shield, seepage can only
occur in a limited number of waste packages because of the efficiency of
the capillary barrier. The point here is, if you let a geochemist get up
and talk about geochemistry, they\'ll talk until the cows come home, but
we have need to keep this kind of thing in perspective that we\'re
talking about various scenarios that may, in fact, either not come into
play at all or only come into play in a limited set of conditions.

And so back to this slide here now, the definition of below-boiling
period, now we\'re looking at the period where boiling at the drift wall
ends somewhere around, for an average waste package, 750 years or so.
How far out here you take it depends on your point of view. Joe Payer is
going to be showing some evidence in the next talk that really below
about 90 degrees Centigrade, corrosion is not a significant issue. So
you can\--if you chose that, then really the window that we\'re looking
at here is somewhat narrower. But, obviously, it corresponds to this
kind of period where the RH now is going from about 65 percent, in this
case, close to\--yeah, about 65 percent up to as much as about 80 to 90
percent. So that\'s the temperature RH window that we\'re going to be
looking at during this period. Next slide, please.

And so the processes that affect chemistry of the solutions in drift
environment include the initial pore water chemistry and also the
thermal-hydrologic-chemical processes in the rock. I want to make this
point, hopefully, quite clearly in the presentation that it\'s not
necessarily a simple evaporation of pore water chemistry. There\'s
modifications to the water that we can document through these THC
processes, and they have to be considered. And then, finally, the
evaporative processes inside the drift. Next slide. And so to start
with, let\'s look at the variability of pore water chemistry. Next
slide.

What is the natural variability? Well, we\'ve\--we, I say the Project,
has collected samples of pore fluids, collected and analyzed them from
all potential repository units now. I\'ll be showing you some new data.
I don\'t know if I know every last data point of what\'s new and what
you might have seen before. I know at least some of it. But these pore
waters show a substantial range of major cation proportions, especially
calcium, sodium, and important anions, chloride, nitrate, sulfate, and
carbonate. So, there\'s definitely a range involved here. But observe,
for example, is that calcium generally becomes less abundant with depth
due to calcite precipitation and, to a lesser extent, ion exchange with
sodium. There is a depth trend there.

Nitrate/chloride ratios, which are of course important for metal
corrosion, are quite variable here. So, what we want to do is take those
natural pore water compositions, basically use them\--I\'m starting to
talk about some of the procedure here\--use them as boundary/initial
conditions for the THC simulations such that they span the range of the
entire ambient system. Next slide.

And this is one of these ternary diagrams, quadrilateral diagrams, that
you\'ve probably seen quite a bit of here. If you focus on the cations,
this actually represents all the pore water samples from the actual
repository horizons; the upper lith, the middle non-lith, the lower
lith, and the lower non-lith. Color coded and, this way, you can see
focusing, for example, on the cations that you get the middle non-lith
and the upper lith clustered quite nicely but still showing some
evidence for a distinct trend in terms of exchange with sodium such that
when you get to the lower stratigraphic horizons, the lower lith, we\'ve
actually got significantly higher sodium in the pore waters and then
even some samples from the lower non-lith that fall down here with
essentially no magnesium in there at all. So, there is some evidence
here of a trend to this, this sort of

\--this array of calcium and sodium numbers. Here, also, trends in terms
of bicarbonate versus chloride, which is the dominate cation.

Now here, up here, portrayed as the same data, of course, projected onto
this quadrilateral, this is where we\'ve shown the compositions that are
actually chosen for THC model input; chosen hopefully such that they
span the range, encompass the range of variability observed in the
natural system. We can see one of our samples. W-0 quite closely
approximates some HD perm waters that were collected in the past.

Some of these waters here in the middle non-lith are actually new
analyses. I don\'t think all of them are, but some of these are new.
They actually cluster quite nicely here and define this set of samples
as a bona fide type of water within the mountain there, but we\'ve also
selected compositions that cover the remainder of the range. About the
only part of the range we haven\'t covered significantly here are some
of these yellow samples from the lower non-lith. I should point out
those are about three percent of the repository, so they\'re not all
that significant. They\'re close, pretty close, to underneath the
repository. The rest of these are not underneath it. They\'re well
within the repository horizons. But you can see, in fact, those are
sodium-rich analyses.

One of the points about this, in fact, is that these new samples which
cluster quite nicely here\--in fact, it\'s not shown on this diagram,
the nitrate numbers\--but, in fact, a lot of these or all of these new
analyses have quite a high nitrate with very consistent values ranging
between about 35 and 44 ppm. So, whether that suggests that, in fact,
most of these higher chloride values should have higher nitrate, we
still haven\'t established that. That shows up in the next slide.

As I said, quite a variable range here of nitrate/chloride ratios, but
some of those I was referring to in the blue actually cluster quite
nicely with significantly higher nitrate values even though their
chloride is high there. So this is a natural variability in nitrate
chloride along with all those other chemistry that we want to take and
propagate through the natural system.

Now, this does bring up the issue of whether nitrate could be reduced or
degraded in the natural system. I think it\'s possible that some of
these reactions might occur at higher temperature as long as there\'s
not complete dry-out. But the question is, we don\'t see any reason why
there should be more nitrate degradation, microbial reduction, at higher
temperature than we basically\--than we observe now in the ambient
system. In other words, I think the ambient system is probably capturing
whatever degradation is going on there.

It should be pointed out in general that the nitrate reduction is not
going to be favored in this kind of environment because of the presence
of abundance oxygen. Basically, any electron donors of which organic
carbon would be normally the most important are going to follow aerobic
respiration as a preferred pathway. They\'re going to use oxygen. It\'s
really usually only nitrate reduction is observed when you get a
depletion of oxygen as occurs, for example, in organic-rich sediments or
some environment like that. So, it doesn\'t seem to be a significant
issue beyond what sort of levels we\'re observing today. Next slide.

So now we\'ll look at the effect of THC processes on seepage chemistry.
Next slide.

The purpose here is looking specifically at fracture fluids because
they\'re the ones that can seep, potentially seep, into the drifts. The
pore water chemistry are actually only indirectly relevant because it\'s
not necessarily driven out of those pores. Purpose is basically to
propagate that range of ambient pore water compositions through the THC
processes to determine the chemistry of potential seepage. So, again,
rather than evaporating directly, we\'re processing those pore waters
through the THC system.

Conceptual approach: Capture coupled effects of solution-mineral-gas
reaction, gas-liquid transport, and heat transport in the mountain. And
we validate it. I keep saying we, I didn\'t do much of this myself, but
this is the royal \"we.\" The validation is principally through the
drift-scale test, and I can show you a little bit of that again, but
also laboratory experiments. Next slide.

And the conceptual model for THC is, of course, this is mostly the
period above-boiling, but that affects to some extent what we see later
on. You get a boiling zone with CO~2~ evolving along with a water vapor,
recondensation of that water in the CO~2~ above, so you get a CO~2~
depleted zone. Of course, the boiling does lead to a zone of active
silica precipitation, a certain amount of calcite precipitation, and
very small amounts of salts are dumped out, much of it actually in the
pores in the matrix, the rock matrix, where it\'s not readily
accessible, but a certain amount does get formed in the fractures.

The key limit, as Bo was discussing earlier, is that you\'ve got a
fairly dilute fluid and your boiling front doesn\'t sit there refluxing.
It basically moves back out. So, the amount of salt that you can dump
out there is basically whatever is present initially in the water, which
is quite a small amount, minus what\'s being left actually in the rock
matrix. So, the concentrations of salts are somewhat limited. But this
is a kind of conceptual model, and so what we\'re going to do is look
specifically at the period where the THC now has tracked the wetting
front, or we call it the rewetting front, as it comes down to the drift
wall where seepage now has a chance of occurring, and see what kind of
compositions emerge from that.

For that I\'d\--next slide\--look at some of the validation experiments.
You\'ve seen this one before, the drift-scale test, which heated for
four years to 200 degrees in the drift environment and now over two
years of cool down; a lot of geophysical characterization and
hydrologic, but also a certain amount of chemistry I\'ll be showing. You
can see this looks like a pin cushion here. And in the next slide, I\'ll
show you some of the results.

So, this has been used as it\'s used for thermal hydrologic validation,
also for chemical validation, focused mainly here just because the
limits of time on the CO~2~, but it shows some aqueous chemistry. This,
for example, shows a modeling of the CO~2~ around the drift-scale test.
And we can see actually in the orange-ish colors a depletion zone I
mentioned earlier. And then when you get out to this region which
would\--blue here\--correspond to the condensation zone is an enrichment
in the CO~2~. So, you get this kind of trend developed.

This is captured quite well in the modeling shown in blue here versus
actual data points. This is CO~2~ versus test duration. So, you can see
a good\--do a good job of capturing the evolution of these acid gases as
they move out from the boiling front. And this is partly why we were
saying in the earlier talk that of all the aspects, I think\--Eric could
correct me if he disagrees with it\--but I think of all the aspects of
the chemical portion of the DST that\'s been validated, probably the gas
chemistry has been done the best. So, when we make comments, I think,
about what acid gases are going to do, it\'s based at least on some
modeling and some reality as captured in this test.

In addition, though, we do have samples of waters here showing calcium
starting at about 100 ppm, and this is primarily the results of dilution
in this condensation zone here. This was touched on a little bit by Bo
as well. So, we are getting dilution in addition to some reactions going
on. Next slide.

We also have validation in the form of laboratory experiments. Here is a
two-part laboratory experiment starting with distilled water with a
fixed PCO~2~ in the column, pumped through a tough column of
pressed-tuff to measure effluent chemistry and try and match that
effluent chemistry and make sure you know what you\'re doing with that
part of the stage. And then the second part is, basically, take what\'s
come out of that column, put it in a reservoir, and pump it through this
fracture system with a temperature gradient from 80 to 130 degrees such
that you\'re going to get a sub-boiling region, a boiling region, and a
super-heated region. So, that\'s this fluid coming through there. This
is the kind of results you actually see. Here, a slab showing from 80 to
120 degrees. You can see right about 100 degrees the appearance of this
silica precipitation front as the water gets boiled away and you
re-precipitate these. Amorphisilica is the major phase there. Next
slide.

And that\'s captured pretty well in the modeling here. The effluent
chemistry is captured in the modeling quite well. And, in addition, the
modeling captures in general this propagation of the fracture ceiling
mechanism, this dumping out of this silica from solution. Next slide.

And so really all this validation was to provide some basis for
believing what I\'m going to show now, which is the THC model
predictions, which then provide our potential seepage compositions. So,
this is what I\'m going to present in terms of conceptual understanding.
In fact, it\'s what\--the way it\'s actually done in the TSPA, just to
give you an idea what\'s being done there. And so what you see now\--so
we\'re focusing now, basically, in the crown of the drift. Right above
there is a function of time and how that chemistry is predicted to look.

You see, for example, focusing on chloride and fractures, that basically
we pick up the variation of the natural pore water chemistry reflecting
those different water chemistries. This would be that so-called W-0
water that\'s more chloride-rich. No seepage here, of course, during the
boiling phase. That\'s why it\'s blank. There would actually, of course,
be some evolution, but that\'s all back up in the rock. And then once
boiling stops, we do see the rewetting front appear. We do see a kick in
the chloride concentrations, a short-lived kick in the chloride
concentration.

This basically represents that rewetting front dissolving those salts
that were dumped out in the initial portion of the system when the
boiling front receded from the drift. So, this is a quite short-lived
front basically because of the limitations of the amount of salt that
was actually left behind there. And then, basically, hopefully to answer
Thure Cerling\'s question, we then in this case returned quite quickly
to the ambient concentrations. Don\'t look very much different.

You see a little bit different story with the more reactive
constituents: calcium bicarbonate, which of course is important in terms
of this calcite divide. Generally we\'re well below the divide again
except for a short-lived peak during rewetting here and then some
gradual rebound to the ambient values.

Nitrate chloride in this panel here basically showing very little
affect, if at all. And these are basically because these constituents
behave largely conservatively in the overall system. In other words,
when you get enough water to actually rewet and seep the system, you\'ve
already got enough water to dilute the system and dissolve all the
halite and dissolve all the nitrate minerals. If you were ever down at
the period where you got just the nitrate minerals in solution, the
volume of water would be so minuscule you\'d never drive flow there.

The CO~2~ in the fracture is showing and, of course, evolution that\'s
continuous through time, the depleted zone during boiling, and then the
rebound once the rewetting comes back up. So, again, these are feeds to
the evaporative in-drift chemical models that we\'re going to look at
now next. Next slide.

In-drift chemical processes. So what processes are important there?
Temperature difference probably is the key one between the drift wall
and the waste package because it creates a gradient in the RH. Where
seepage occurs, basically the drift wall, RH is about 100 percent, but
then these drips move to lower RH inside the drift environment driving
evaporation and concentration of the seepage water. And how that initial
solution composition along with a temperature and RH will determine the
actual reaction path that this solution follows once it starts
evaporating.

It\'s important to point out that concentration of fluids not only leads
to simple concentration, conservative concentration of constituents, it
eventually leads in most cases to mineral precipitation and thereby
depletion of solution in components. So it\'s not very easy, for
example, to develop extremely high fluoride concentrations in a system
which has a natural water that has calcium simply because you
supersaturate with respect to fluoride, and you start pulling that
fluoride out of solution. So, both of these processes are going on. Next
slide.

And what we\'re basically building into this in-drift evaporative model,
this is just a schematic of it. In fact, it\'s basically EQ3Q6
calculating all of the system including the activity of water as a
function of temperature and relative humidity, that is the activity of
water. But built into this is the kind of thing that\'s shown here, that
the reaction path is governed by this kind of chemical divide theory
where you start with a dilute water and, for example, a mineral
precipitates. These don\'t all concentrate equally. You pull these
constituents out of solution.

In one case, for example, a carbonate less in calcium, you could develop
a sodium calcium brine in this, a chloride brine in this way. Or if
you\'ve got carbonate in excess of calcium, generally you deplete the
system of calcium right away, and you end up with basically a sodium
chloride system with mostly carbonate, excess carbonate, in solution.
But this kind of process that we call the chemical divide process is
captured in those geochemical models, but is done with all the minerals
that could form in the system. Next slide.

And so our approach here to evaluating the chemical evolution is really
a two-part one. It includes experimental investigations with detail
evaporation studies of solutions, literature data on salt solubilities
and deliquescence, and also heterogeneous studies of multi-phase salt
systems. I think both these bullets all involve new data that the Board
hasn\'t seen. You can correct me if I\'m wrong. And combined with that,
it\'s not called new data, but some of it is quite new. We also have new
modeling that involves an updated thermochemical model, EQ3Q6, that\'s
adapted from multi-component salt-brine systems. It has a state of the
art Pitzer database to deal with activity corrections at high ionic
strength. And we\'re going to be showing at least some comparisons
between the model and the data just to show that we\'re on the right
track, that there\'s some validation. Next slide.

One of the\--so this is the section on experimental studies. I\'ll just
review this, hopefully, briefly. Next slide shows one of the
apparatuses. This is basically a series of follow-on experiments to what
Rosenberg had all did a few years ago. The key difference, from my
understanding, is that there\'s a much better control on the gas
chemistry over the top of the evaporating solution. This was a little
bit hazy in the earlier one. So very careful gas and RH control along
with the ability to sample the gas chemistry. Next slide.

And so this shows some of the results for a sulfate-type water and a
carbonate-type water. You can see the model results are the lines,
whereas the data are actually these points here. You can see models of a
fairly simple one here, potassium nitrate going up conservatively.
There\'s no precipitation even though you\'ve come up to a concentration
factor greater than 1,000. However, in the case of sodium chloride, you
can see once we get up to this point that the chloride and the sodium
level off. We basically started precipitating sodium chloride there,
captured calcium and sulfate, as well.

Magnesium, we never really get up to very high concentrations of
magnesium. Basically, millimolar level, there\'s just tens of
millimolar, but we\'re picking up at least a little bit of a decline, it
looks like, in magnesium here. One of these experiments was the one we
mentioned that actually they found magnesium\--this may have been later
in the series\--found magnesium sheet silicate developing in solution.
Here\'s some of the modeling results comparing carbonate waters. So
these are new data that are meant to corroborate, validate the
validation, to corroborate the modeling that\'s being done here. Next
slide.

Here\'s just a comparison of the model against solubility data from the
literature. Literature being basically Chemistry Handbook Solubilities
here, 25 and 100 degrees, so at temperature range, but also a very
significant concentration range. You can see about five orders of
magnitude. The model was able to capture those solubilities. Quite
importantly, significantly, at 100 degrees doing quite well at even high
concentrations of these salts here, clustered around there. So, the
model is able to capture this. Also, I\'m focusing on individual salts.
We can see we capture both the solubility here and the deliquescence RH
of the sodium chloride system, magnesium chloride as well, captured
quite well except for that minor discrepancy right there. Next slide.

And the last experimental component I want to mention is just these.
I\'ve already presented at least some results on it. And these reverse
deliquescence experiments involve reversal in environmental chambers
where the RH and the temperature is controlled. Reversal, basically,
involves starting with a solid and raising the RH and letting water
absorb and then measuring the chemistry. And then the reverse, of
course, evaporating, measuring the chemistry in both cases, monitoring
where you are in RH space. Some of those results are shown in the next
slide.

Two of the results, a sodium-chloride-potassium-nitrate system and
sodium-chloride-sodium-nitrate. You can see here, again, the initially
solid ones are red, initially dissolved are black. And the Pitzer model,
the so-called Yucca Mountain thermal-chemical model, is the lines here.
We have some discrepancy here, but we capture the eutectic point quite
well in terms of RH and the mole fraction sodium. The potassium you see
here would be the deliquescence point for sodium chloride.

Similarly in this system here, deliquescence of sodium chloride here,
sodium nitrate down here. Some discrepancy between the eutectic point,
but really only a few percent in terms of RH, and a few percent in terms
of the actual mole fraction of nitrate. So, these are all reversed
experiments that demonstrate we\'re on the right track in terms of the
thermochemical model at quite high concentrations. Next slide.

So now, that was the validation, basically, the chemistry. Some I want
to present, some of the key results, in terms of the in-drift chemistry
analyses in the next slide. Just to summarize in advance, the main
results that we want to pick out here, is that, first of all,
calcium-chloride brines are very unlikely to form during the
below-boiling period. And this, basically, because of dilution and
mineral reaction associated with THC processes, but also then further
reduction of the calcium concentration by evaporation. I\'ll come back
to more discussion of that.

Evaporation, the second point, is that evaporation of seepage water
leads to very large decreases in fluid mass. This is, again, one of
those points in terms of perspective talking about fluxes that you have
to keep in mind. We\'re not talking about big beakers of water or
anything like that or oceans floating up in the drift. We\'re talking
about quite small amounts of brine that develop, but I\'ll try and
quantify that.

And then finally, I want to look briefly at a time-temperature-RH
history for the drift and couple that to the evaporative chemical
evolution. This is just one example. In fact, this is kind of a snapshot
of what\'s actually done in the TSPA. Next slide.

And so this key point: The calcium chloride seepage brines are unlikely
to form during the below-boiling period. In fact, our analysis shows
that you can form calcium chloride to some extent in the above-boiling
period, but basically up in the rock and also to some extent in the
invert where you basically do something more like direct evaporation
pore water. But I think a key reason that these brines do not form in
our analyses and I think in a reality, as well, is that we need to take
into account these THC processes which are acting to reduce the calcium
in the potential seepage fluid basically due to a combination of
dilution and mineral precipitation.

Minerals precipitating in that stage are mostly calcite in fractures,
but also a certain amount of stellerite, zeolite in fractures. Both of
those minerals are actually observed at Yucca Mountain. But some of that
is captured, I think, the dilution especially is captured, again, in
showing this Borehole 59 result which shows that you\'re reducing
calcium concentration to these dilution effects that I think Bo was
touching on previously. That, of course, becomes the potential seepage
water.

We get further decrease in calcium and solution due to mineral
precipitation. In the drift, especially, the key players that we see are
calcite and fluorite evaporation. Basically, it drops the calcium out to
nothing. So, from our analyses is that these seepage brines, despite the
appearance of some of these chemical divide plots, is that they actually
don\'t form. It\'s a little bit misleading. And I think it has to do
with the fact that those generally consider direct evaporation of pore
water, whereas the THC is important in modifying some of these
concentrations. Next slide.

And the second point I want to make is basically that evaporation vastly
reduces the fluid mass. Perhaps that\'s self-evident, but I think it\'s
still useful to get some perspective here. If you focus now back up in
the drift wall, we\'ve got potential seepage water, quite dilute,
millimolar level. It\'s at a 100 percent RH. If this just came in,
there\'d be no problem; it\'s benign, it\'s dilute, but obviously it\'s
going to concentrate. But you need to keep in mind what happens to those
potential seepage fluxes. For example, here during the monsoon and
glacial transition period, the seepage flux would actually be 1400 and
3100 times respectively the width of this bar graph, which then shows
flux and kilograms per year per waste package. So, it\'s somewhere in
the 10 to 30 kilogram per year that might actually be sitting up above
you.

If we were to focus, for example, now on this period, the potential
seepage flux, it\'s still a low probability because of capillary
barrier. We\'re talking basically about one to two kilograms of water in
the rock that might seep on us. That\'s something on the order of this
volume of water that\'s sitting up there in the drift that has a
potential to seep over one waste package over the span of a year.
However, if you start looking at the volume of evaporated brine that can
develop, you need basically a medicine dropper to represent the amount
that could contact that waste package over the space of a year. And
that\'s basically what\'s shown here.

Once we get down to this level of evaporation, in terms of the RH, which
is going to be the conditions in the drift, that\'s what\'s driving it,
we\'re going to get, at the most, seepage fluxes on the order of tens of
milliliters per year develop there. So, we\'re talking about very small
amounts of water that actually have the potential to accumulate there.
And I think in the next slide that\'s reinforced with looking at
actually what this evaporation does to the fluid flux through time.

Here the procedure is basically to calculate the evaporative fluid mass
reduction using the actual waste package history through time. And what
we see then is that the RH really is the dominant control. Of course,
there\'s some temperature. But it\'s really the RH that determines the
extent of evaporation. And so here\'s a typical waste package through
time. What you\'d see is that those seepage fluxes, if we\--fluids, if
we follow them through time, those are shown through\--shown here.

This is basically what Bo showed earlier, the mean seepage flux starts
quite low at about two kilograms per year. This is just what could seep
again. It doesn\'t mean that we\'re going to get\--all the packages are
going to see that. And then we get the monsoonal and then the glacial
transition. That translates basically to an evaporated brine flux
that\'s three to four orders of magnitude smaller, somewhere around, as
I say, milliliter to tens of milliliters flux rate accumulation
potentially on the waste package. One to a hundred grams of brine,
basically, per year per waste package.

So, I was trying to make the point is that\--well, I\'ll make that
better, I think, in the next slide\--is that when you follow out this
time-temperature-RH history, and here\'s where we\'re going to try and
wrap it all together, and look at the RH evolution. Of course, that
corresponds to a seepage evolution and also an evaporative brine flux,
but very small. So you do get obviously concentration of those seepage
fluids here in the seepage compositions. I\'d say 650 years, you\'ve got
chloride and nitrate in the millimolar level, quite dilute. You could
drink this stuff with the nitrate chloride ratio of something like that.

You do get brine compositions then or, basically, much higher chloride
at or close to saturation with halite and nitrate somewhat below
saturation of any of the nitrate phases. We do get some improvement in
the nitrate/chloride ratios due to the fact that a certain amount of
chloride actually precipitates out. So this kind of tries to couple the
time evolution together. You can see that there\'s periods where the
waste package potentially can see high chloride/nitrate ratios, mostly
sodium chloride is going to be\--but that\'s associated with very, very
small amounts of fluid actually collected on the waste packages. Next
slide.

And so to try and wrap it up, this is that slide we showed earlier.
Basically here now we\'re focusing on this period starting with that
yellow triangle and on up to say wherever corrosion of the waste package
becomes insignificant, but basically considering this part of the
trajectory. So, we are spending most of that time in the region where
we\'re not getting a thermodynamic control on the nitrate/chloride
ratios. In other words, those brines, if seepage brines do make it
through, are going to basically reflect the ambient nitrate/chloride
ratios in the ambient system. And a few packages, like the hotter ones,
will still see some thermodynamic control, but most of them will not.

This is kind of the field that we end up in during this below-boiling
period. Eventually we get a high enough RH, the sulfate minerals become
soluble, and sulfate becomes another potential inhibiting anion. Next
slide.

And so in conclusion, although the evolution of the seepage water
chemistry is complex, there\'s no question about that, DOE has developed
a scientifically defensible, integrated approach that couples the
chemistry to the time-temperature-RH history of the drifts. This
approach considers both the natural variability of pore water chemistry,
capturing the range observed in the repository horizons, but also
modifications to the pore and fracture water chemistry as a result of
the THC processes. And then finally links that to the evaporative
concentration resulting mineral precipitation where seepage actually
occurs. And this approach then is implemented through a combination of
experimentation and modeling. Next slide. This should be the last, I
believe.

Conclusions is that the seepage will not result in calcium chloride
brines during the below-boiling period because of the precipitation of
calcium mineral phases both during the THC stage in the rock, in other
words, and in the drift. In hotter waste packages during the
below-boiling period, thermodynamic controls do result in a favorable
nitrate/chloride ratio for those hot packages, but most will not really
see much of an improvement in those ratios.

Evaporated brine fluxes are on the order of 1 to 100 milliliters per
waste package per year as a maximum, again assuming that the capillary
barrier was not operating. And, in fact, that leads me again\--we\'ve
gone down this long road, I want to make this comment one last time. In
the expected case where very little seepage on waste packages occurs due
to the effectiveness of drip shields and the capillary barrier, the
foregoing discussion on seepage chemistry, is irrelevant. And this is, I
think, where the drip shield comes back in and potentially is important
in shielding the waste package from some of these solutions.

Thank you.

LATANISION: Carl, thank you very much. You\'re right on time. We have
about a 20-minute period for questions. Let me actually begin.

Now, this is Latanision, Board. Can we turn to number 36? Carl, in your
conversation you describe the nitrate-to-chloride ratio as being
favorable, and I think in your concluding statement, comment is made as
a favorable ratio. But is the issue of it being a favorable ratio based
on something other than the tests that were done in magnesium/chloride
salts? How do we know it\'s favorable under these conditions?

STEEFEL: Yeah, I should make a few points. One is, I don\'t know if that
was the right choice of word. It was mainly to say that they, at least
in this slide, that the nitrate/chloride ratio had improved a bit
relative to what\'s observed in, say, the seepage water which is going
to reflect ambient. So, in certain cases because of the precipitation of
halite, you get an improvement in that. My understanding that, overall,
the issue of nitrate/chloride ratios has been evaluated in the whole
series of experiments involving different corrosion tests, but that\'s
going to be what Joe is going to talk about in the next\--the next talk.

LATANISION: Latanision, Board.

Are we on? I\'m\--you know, I agree. I\'m prepared to wait for Joe\'s
comments, but this is an issue in my mind. My recollection is that the
data that showed the inhibiting effect of nitrates was based on either
magnesium or calcium chloride brines. And I don\'t know that there\'s
data that shows the\--maybe I\'m incorrect. Greg looks like he wants to
make a comment.

GDOWSKI: Greg Gdowski, Lawrence Livermore.

Joe Payer will actually show some corrosion studies that were done in
sodium and potassium containing solutions of chloride and nitrate.

LATANISION: Okay, these must be more recent tests; is that correct?

GDOWSKI: Within the last year, yeah.

LATANISION: Okay. Then I\'ll reserve my question until we get to that
point. Thank you.

Any other questions? Dan Bullen.

CERLING: Cerling, Board.

Could we go to slide 11? What I\'m wondering about in this figure here,
that one of the key issues in the chemical divide concept has to do with
anions down\--the anion triangle down there in the lower right. And I
was just wondering, in the middle non-lith, the purple zone, there seems
to be two sorts of chemistries that seem to fall out of that zone; the
red dots and the green dots all seem to have a pretty uniform
composition. Could you or somebody in the Project explain to me why
there are two, sort of, clusters of the purple dots?

STEEFEL: Probably the best one to answer that would be Eric. I don\'t
know\--

SONNENTHAL: Eric Sonnenthal, Lawrence Berkeley Lab.

I can probably answer part of that. Maybe Zell Peterman can add more
because they collected the data.

The first set of water HD perm, which was in the upper group collected
several years ago, we don\'t really know if there really are two groups
of waters. I don\'t know if we have enough data to say that the middle
non- doesn\'t span into that other regime. So, I\'m not sure if\--I
mean, obviously, it does look like there are two, but there are also
differences in spatial. There\'s spatial differences, which also result
in different depths to the surface and different infiltration rates. We
know that the sample collected at HD perm is in the eastern part of the
repository, right at the edge, where infiltration rates are lower than
in the western part under the\--in the main part of the repository.

CERLING: I guess. And then I\'d actually like you to comment on your
backup slides if you could?

STEEFEL: Okay, which\--which one is that?

CERLING: Cerling, Board.

Starting with 41, the\--your backup slides has some discussions of flow
separation which certainly Catholic University has brought up before.

STEEFEL: We took these out of here. Yeah, the issue here was we figured
we wouldn\'t focus on this in the main talk just because of lack of
time, so I put them in the backup, but the issue there is that it might
have a good\--probably should have a good conceptual diagram\--but that
in the last stages of evaporation because the nitrate minerals are more
soluble than the chloride minerals, if you\'ve actually got flow on some
surface developed, in principle, you could then leave behind the
chloride-rich minerals as the solution continues to move down whatever
surface is involved there, and that you\'d basically get a separation of
your nitrate and chloride in solution.

Then you would basically leave behind chloride minerals which would now
at this low RH, such that\--you have to have a low RH or you wouldn\'t
evaporate it to that extent

\--you\'d basically have a non-deliquescent chloride mineral with the
nitrate moving on. Perhaps later, as the RH climbs up, you\'d then get
deliquescence of a more chloride-rich solution there. So this, actually,
this process is incorporated into the TSPA, that to some extent it is
going to occur, some flow separation will occur.

The major argument, I think, against it is simply, again, you have to
keep in mind the fluid volumes here that this separation of nitrate and
chloride, and I showed that in one of the validation slides, basically
occurs at concentration factors well over 1,000. So, you\'re talking
about fairly small amounts of seepage that come in and then dry out. The
question is, do you have enough volume there to maintain actually a drip
that can now continue to propagate down a surface, given that the
surface presumably has some natural roughness, capillarity, whatever,
that\'s going to tend to keep that moisture there.

So, I\'m not sure we can make an ironclad statement. In fact, that
statement isn\'t made. It is incorporated in TSPA, but I think there\'s
a\--I don\'t think it is a really significant effect unless seepage was
much greater amounts than is presently observed. Again, because you\'re
cutting those seepage fluxes by a factor of 1,000 to 10,000, you don\'t
have the hydrologic driving force to continue to propagate that drift.

LATANISION: Dan Bullen.

BULLEN: Bullen, Board.

Could we put figure 20 on this slide and figure 37 on that slide? One of
the\--yeah, perfect.

I had a question basically with respect to timing. As I look at figure
37 over here, I see the sort of light blue region where the
nitrate-to-chloride ratio is less than .5 possible as being an area that
we\'d kind of like to avoid. And I\'m trying to get a handle on the time
frame in which we\'re going to be in that regime. And so when I go to
figure 20 and I take a look at the time steps for the concentrations
that you see for potential seepage compositions, I see that there\'s
sort of an instantaneous, as I go out of the boiling regime, you know,
kind of one time-step that I\'m away from it, but how long in actuality
would I be within the region where I don\'t want to be, which is the
nitrate-to-chloride ratio of less than .5?

STEEFEL: I don\'t know if\--I don\'t know if this is the best one to
compare that. Those represent different waste packages with
temperature-RH histories. But, basically, you\'re asking what period of
time you\'d be in the nitrate/chloride ratio less than .5?

BULLEN: Exactly. Those\--

STEEFEL: You wouldn\'t necessarily be less than .5. It just means you
get back out your ambient pore water compositions. It just means
there\'s no thermodynamic control. So, basically, I think the best one
to look at is over there in this slide on this side. Basically, in this
case, from about 700, a little bit before\--well, the boiling period
starts\--ends at about 750 years, so you\'d be there up to\--I\'ve
forgotten. Actually, we should look at the other slide. Could we go to
slide 4 or 5 over here? That\'s the one that maps to this scenario most
closely. I think it\'s in 5 or 6. Next one. There we go.

That would correspond to a period, basically, all the way up to where
you hit 80 percent RH. This is where the sulfate minerals kick in. It
doesn\'t really modify the nitrate chloride. Otherwise, it would be over
the entire period, below-boiling period, until waste packages dropped
below 90 or whatever best figure there is for where corrosion is
insignificant. So, most of the below-boiling period is going to be spent
in this period, in this area, where you\'re basically not getting
thermodynamic control on those ratios except for those hotter waste
packages. And, again, this is all bundled into TSPA. In other words,
TSPA samples this entire distribution.

BULLEN: Bullen, Board.

So, just to follow up, I guess figure 7 is a better representation, but
as I look at that, it\'s what? Maybe 700 or 800 years?

STEEFEL: Right\--

BULLEN: And the cooling time that\--

STEEFEL: \--I believe so. The 750 to about 1500, yeah.

BULLEN: Okay, thank you.

DIODATO: Diodato, Staff. Diodato, Staff. Am I on? Okay.

Yeah, Slide 35 is of interest to me. This is maybe just a small point,
but looking at the mean seepage flux number you have there, I mean, the
mean is good to have a handle on, but with 10,000 or 11,000 waste
packages, it\'s also nice to have an idea of the range, the variance on
that, about that mean because I suspect that sample data set is
dominated by zeros for the most part. So, what you\'d really like to
know is, you know, what are the maximum and how many waste packages are
exposed to these higher seepage fluxes? So, I don\'t know if you have a
handle on that or\--

STEEFEL: I\'m not sure I\'m the best person, but actually my
understanding of it was that this is not the actual number of packages
that are going to see that seepage. There\'s a much smaller percentage
of packages that can actually see that mean seepage flux. And within any
one period, it\'s somewhere, I think, in this period on the order of,
say, five percent. Then it goes up to 15, and I don\'t think it ever
gets to 30. So, that\'s the overall mean seepage flux that any one
package might see if the capillary barrier failed.

So, the number that actually see that is considerably less than that.
But you\'re right. Basically, there\'s a significant distribution there.
We just tried to pull that out, you know, mostly for a sort of almost
pedagogical purposes to make this kind of argument. But there is a
significant range and, in fact, again, that\'s the kind of thing that
would be sampled in the TSPA.

DIODATO: Thank you.

STEEFEL: But if that was incorrect, I think Bo can come up and correct
me. But I\'m pretty sure that this doesn\'t mean that all those waste
packages are going to see it. You apply then an additional factor
related to the capillary barrier which reduces that by a significant
amount of something like 5 to 10 percent.

DIODATO: Well, if you redistribute the mass flux to a smaller number of
packages, then that particular flux for a particular package should be
larger; right?

STEEFEL: Not necessarily because a lot of it just goes past and sheds
off the system. So, that\'s the flux that it would see if\--this is my
understanding\--the flux that it would see if the capillary barrier
didn\'t work, but otherwise somewhere else. You\'re not just diverting
that and getting a larger mass of water on those that seep. You\'re
getting some of your waters diverting around those packages.

DIODATO: Thanks for your explanation.

LATANISION: Do we have any questions from the audience?

SHETTEL: Don Shettel from the State of Nevada.

Can we have slide\--Slide 26? This experiment looks like a closed-system
experiment. Did you have a stir in the bottom? Is that correct?

STEEFEL: I believe it is because you\'ve got a condenser, at least. Greg
is the one who worked mostly on that.

GDOWSKI: Yes, Greg Gdowski, Livermore.

No, it\'s actually a flow-through system. There\'s a constant stream of
air flowing over the top of the fluid.

SHETTEL: I\'m not referring to the gas system. I\'m referring to the
liquid system.

GDOWSKI: We\'ve run them both ways. We\'ve run tests where we keep the
water-level constant. And also we\'ve run a test where we evaporate down
the water. So, both\--both cases have been run.

SHETTEL: Yes, but what I\'m referring to, there are two ways to model in
geochemistry. One is a closed system where you allow all the mineral
precipitates to remain in equilibrium with the solution. And the other
one is where you remove the mineral system so it\'s essentially a
flow-through system.

GDOWSKI: It\'s a closed system in that sense, yes.

SHETTEL: Okay, is that the most conservative approach? Or would an open
system be a more conservative approach?

GDOWSKI: It depends what you\'re trying to understand. The point of
these\--

SHETTEL: Well, this\--

GDOWSKI: The point of these experiments was to validate the EQ3/6 model
and to understand the initial chemical divide theory as it applies to
these waters.

SHETTEL: Yeah, but EQ3/6 can be run both ways.

STEEFEL: Well, the issue, I think, was that it\'s meant to capture also
one case where you basically drip a small amount of water on a waste
package and then it sits there. So, there is one end-member case.
Whether you call it conservative or not, I don\'t know, but it certainly
realistic where you can actually have a closed system developed on the
waste package. As I discussed with the flow-separation, there\'s certain
scenarios where it might run off actually.

GDOWSKI: Exactly.

SHETTEL: Well, I\'m not calling it conservative\--

STEEFEL: Now, one point to be made is that if you\'re talking about in
the rock, actually that\'s a full reactive transport calculation. Those
salts get left behind when the fluid moves and this and that. So, it\'s
really only an issue on the waste package. And, you\'re right, this is
an experiment that\'s the closest and the\--

SHETTEL: Well, some of the salts could precipitate in the rock and
before it hits the waste package. And\--

STEEFEL: And that\'s captured in the model as a transport and flow
phenomenon.

SHETTEL: Well, you show on one of these diagrams that the salt totally
concentrates in the rock before it hits the waste package, I believe.
I\'m not sure which slide it is.

STEEFEL: I don\'t know if I\'d use that wording, but I\'ll reword it.
The way I said it is there\'s a small amount of salt precipitated out of
a very dilute water as the boiling front recedes. And so, obviously, as
that boiling front collapses back down, rewetting occurs. Water is going
to start going into those fractures and seeing that amount of salt
that\'s been left there. And so, yes, there is going to be some
re-dissolution of the small amount of salts in the original pore waters.
But what we were contesting originally was this business of refluxing.

Go ahead, if that was\--is that your question?

SHETTEL: No. My question is, I mean, you can evaporate the water in the
rock partially or you can evaporate it on the canister. If you evaporate
it on the canister, you can have\--you don\'t need such small volumes to
hit the canister. The water\--since it\'s a curved surface, it\'s not
very likely that the water stays in one spot. As it evaporates, it\'s
going to run down the curved surface.

STEEFEL: No, but my\--this is\--my point was is that this\--if\--are you
talking about chloride/nitrate separation?

The issue of chloride/nitrate separation, if that\'s what you\'re
talking about, only occurs in the very last stages of evaporation. So,
even if your original seepage flux is a good quantity of water like
this, this container here, you\'re really only going to get that
separation kicking in when you concentrate it a thousand times. Now, you
could have the rest of that scenario, it\'s true, develop, like leaving
calcite behind. You could leave calcite and other things behind, but
that\--

SHETTEL: Okay, so\--

STEEFEL: The chloride/nitrate separation is only in, you know, when your
brine fluxes are smaller.

SHETTEL: Are you saying that if you separate the chloride and the
nitrate that that is a good thing for corrosion?

STEEFEL: No, I didn\'t say that. I didn\'t say that. I said that I\--it
could potentially\--

SHETTEL: You said it could occur, yes.

STEEFEL: Yeah, I said it could occur. And then, in fact, it could be
potentially deleterious because the nitrate then moves on, leaves a
chloride salt behind initially. That\'s going to dry out because it\--if
it was\--the reason it\'s left behind is because it precipitated. But
then as the RH climbs back up, that could then deliquesce, and you could
get a more chloride-rich solution. That\'s deleterious, yes. That\'s\--

SHETTEL: Does that separated nitrate solution have any affect on
corrosion?

STEEFEL: Joe may have some experiments on that. I don\'t think so.
Chloride, I think, is the major issue that\'s of concern there.

This, in fact, this experiment is quite similar to‑-except for the
control of the PCO~2~\--is actually similar to the Rosenberg experiment
I was talking to Greg Gdowski\--in fact, that issue we brought up before
about tachyhydrite, that evaporation is basically occurring in the space
of about a day. So, it\'s a very rapid evaporation. The question\--you
know, the problem is that when you\'re talking about magnesium and how
that reacts with silica, that does take longer periods of time,
generally more than a day. Silicate rates are known to be slower.

But, again, we\'re back to that question: What\'s the relevant time
period? I would say it\'s\--the time period is where you have a chance
to generate in corrosion. In other words, if within two weeks you can
react that magnesium with a silica in that local environment, then
that\'s still good enough. That\'s pulling the magnesium out of the
system, out of solution. I guess I should have\--

SHETTEL: Well, that depends where things precipitate and how solutions
flow whether you pull the magnesium out or not. If you have a
flow-through system, it\'s less likely. Usually what we see in
experiments is the silica precipitates out; therefore, there\'s not much
left to pull in magnesium or pull out magnesium.

With regards to tachyhydrite, I believe you said before that might be an
unstable-type phase or something.

STEEFEL: That\'s what I\'m arguing, basically.

SHETTEL: Well, I think the very fact that it has a name and is a mineral
means that it does have some stability and is found in nature somewhere.
So, I don\'t think you could say that it\'s exactly an unstable phase.

STEEFEL: Well, I think you could say it. It is\--it\'s an unstable
phase. I mean, the same argument about antarcticite. When you\'re
talking about, you know, people discover new minerals, they want to
publish them in the journals, but that doesn\'t mean they have any
widespread thermodynamic stability. Certainly, tachyhydrite is not a
stable phase.

SHETTEL: Well, there\--well, I would disagree with that. It\'s found in
nature, so therefore it must be\--have some stability in a certain
environment.

STEEFEL: Plus we find it in our experiments as well.

LATANISION: All right, any other questions from the floor?

(No audible response.)

LATANISION: I just want, before you finish, Carl, I want\--there was a
question that I wanted to ask this morning that I didn\'t have an
opportunity to ask given the timing. And we do have five more minutes in
terms of my schedule here. So, I\'d like to return to your figure 18
from this morning.

(Pause.)

LATANISION: Yeah. We had a discussion about this at lunch, and then
I\--I don\'t think any of the Board members that I spoke with understood
the reason why we were not seeing nitrate, but were seeing ammonia in
this x-ray analysis. Now, I understand you did analyze the water
chemistry and you found nitrates, but could you just restate or comment
again on the appearance of ammonia? The ammonium article.

STEEFEL: Yeah, maybe Zell can give the best answer. I did talk to him
about this, as well, and there is ammonia dissolved in the actual
leachate that showed up. So, it makes sense that some of it reappeared
there. But, as I understood it, there was nitrate in the solution, as
well. So what happened to it is not clear.

PETERMAN: Yeah, Zell Peterman, USGS.

That is correct, Carl. As you said earlier, we don\'t understand why
we\'re not getting nitrates here. I suspect the detection limit, you
know, is several percent, maybe 5 to 10 percent. If it\'s less than
that, we probably wouldn\'t see it on this. It\'s a pretty routine XRD
work. We were surprised by the ammonia salts. We hadn\'t analyzed the
leachates for ammonia. When we got these, we went back to the raw
samples, leached them again, and did ammonia. And, in fact, they do have
ammonia. That sample one, as I recall, has about 60 milligrams per liter
ammonia. So, that\'s kind of interesting. I don\'t know where it comes
from. Maybe it\'s coming from the underground use of dynamite or
something like that.

The others had much smaller amounts by an order of magnitude, a few
milligrams per liter. That\'s about all we know at the present time.
This was a pretty simple experiment. The evaporation was sub-boiling
evaporation. It was done in a beaker with a heat lamp. We didn\'t
necessarily control the temperature, but it\'s certainly less than 100.
I would guess, you know, 50 to 70 degrees, something like that. So, you
know, this is all\--all this has all happened in the last two or three
weeks. So we\'ve got a ways to go yet.

STEEFEL: Yeah, this is definitely recent data.

LATANISION: Well, let me ask the obvious question. Are you confident
that nitrates are present?

PETERMAN: Oh, yes. We\--

LATANISION: You\'re absolutely certain about that?

PETERMAN: Absolutely certain.

LATANISION: I mean, this doesn\'t\--okay.

PETERMAN: 100 percent certain that there are nitrates present at about
the level given in Carl\'s mean value there on that one chart. I forget
what it was, 10, 15 milligrams per\--or equivalence, milli-equivalence.

LATANISION: Thank you.

PETERMAN: So, we were surprised to see the ammonia salts, but there
seems to be ammonia there also.

SONNENTHAL: I can add\--

LATANISION: Thank you.

SONNENTHAL: Eric Sonnenthal\--

LATANISION: Go ahead, Eric.

SONNENTHAL: \--Lawrence Berkeley Lab.

There\'s some other data we haven\'t shown yet, and that\'s on the
nitrogen and oxygen isotopes of some leachates from the dust from the
tunnel. And they show that some of them are nitrate derived from typical
pore waters in the rock. And some are also derived from other sources,
possibly in-tunnel things that\--and one of them, at least one of them,
showed some ammonia-derived nitrate.

LATANISION: Thank you. We\'re ready to move on and I would like now to
call on Professor Joe Payer. He is somewhere in the room, I suspect. He
is. It will take us a minute to get the panel readjusted.

(Pause.)

PAYER: All right, thank you, Ron, the Members of the Board.

I have the privilege and opportunity to make this presentation on
Corrosion Resistance of Alloy 22. There\'s some folks over here that are
much more involved in the day-to-day testing and a lot of the analyses
that\'s been done here. Up on the panel up here is Dave Shoesmith,
who\'s a professor at Western Ontario? Southwestern Ontario?
South\--just Western Ontario. He has done a lot of corrosion testing,
corrosion modeling, and has also worked closely with the Project on
several of these topics we\'re going to talk about.

Next to him is Pasu Pasupathi. Pasu has about 30 years, almost 30 years,
of experience in materials performance and testing and evaluation in
nuclear systems, nuclear reactions.

Next to Pasu is Tammy Summers, and Tammy is a manager of the corrosion
testing activities at Lawrence Livermore Lab. She\'s been primarily
the\--she\'s one of the principals in the issues of metallurgy and
materials aging issues, that type of thing.

Next to Tammy is Raul Rebak. Raul, from Argentina, had some industrial
experience down there, came to the states, did a Ph.D. at Ohio State,
then worked in industry doing material selection for chemical process
plants and other opportunities of that sort, and then joined the
Livermore team here in the area of materials testing and evaluations,
that type of thing. Raul\'s been one of the driving forces behind the
different methods to measure localized corrosion, comparing and
analyzing, and just seeing what all those tests mean.

Greg Gdowski\'s getting a little bit of a break. He\'s rejoined the
audience out there, but Greg has been very involved in the evolution of
environments on waste packages. And then these people are represented by
a larger number of folks behind. Next slide.

And this just lists some of that. In the evolution environment area,
Greg\'s been assisted significantly by Susan Carroll and Tom Wolery, who
was on the prior panel. In the corrosion testing/analysis area, Tammy
and Raul are represented here. Back getting more data, I guess, are
Gabriel and\--sorry, Gabriel and Lian, and Chris Orme. In the materials
testing area, Bechtel SAIC, Pasupathi heads that area up, and he\'s had
significant assistance by Gerry Gordon. Next slide. Well, I guess the
next slide is shown on both sides now.

This is an outline of talk we want to spend a little bit of time here
talking about, documenting, and reminding you folks of the high
corrosion resistance of Alloy 22 in a lot of different environments. The
talk about Yucca Mountain, we\'ve heard a lot about it today, but what
I\'d like to do is put it in perspective of what is it, what are the
features and attributes of Yucca Mountain that are significant and
important from a corrosion perspective?

We\'ll talk about the corrosion rate of passive metals, which is a very
significant issue. If passive metals remain passive, their corrosion
rates are extremely low. The issue then becomes, will they remain
passive? And that brings us into talking about some corrosion
conditions, corrosion background, and corrosion conditions at key time
periods. Carl showed you some of that, the folks from the Center, NRC
showed you some of their ways of breaking up the time periods. We\'ll
focus on localized corrosion because that remains the biggest issue, I
think, the biggest threat and the biggest issue to determining the life
of waste packages. There are going to be the localized corrosion
processes.

And we\'ll finish that up talking about this Period IV that after the
cool\--after the thermal barrier and while the package is higher than
temperatures, the corrosion can still exist. So, that\'s the road map. I
think we\'ll leave the road map up on that side, and hopefully that will
help you follow along where we\'re at. Next slide.

Alloy 22 is an extremely corrosion resistant material. In any corrosion
application, the corrosion that we observe is a combination of the
corrosion resistance of the material and the corrosivity of the
environment that that material is exposed to. There are environments
that will attack any material. So, there\'s no material we have that\'s
immune to all environmental conditions one could imagine.

The challenge is and the trick is, to win, is to match up a material
with proper corrosion resistance in realistic environments. Alloy 22 and
titanium for waste packages and drip shields are highly corrosion
resistant material in oxidizing environments such as Yucca Mountain.

We\'ve mentioned before, it\'s been mentioned several times today, the
ambient conditions at Yucca Mountain are benign. These are dilute
waters. They tend to be mildly alkaline waters. But even the
non-alkaline waters in the dilute form are benign and noncorrosive,
basically. However, as we\'ve heard from Carl and others, these waters
can become highly concentrated when they\'re exposed to high
temperatures and we evaporate, or in the very early stages of
deliquescence, and so that\'s where the focus is.

The issue is to determine a corrosion resistance of Alloy 22 when it\'s
exposed to these realistic environments. Next slide.

Alloy 22 really belongs to a family of corrosion resistance alloys that
are of the form nickel-chrome-molybdenum, are the primary alloying
constituents. And the nickel-chrome-molybdenum and in Alloy 22, there\'s
some small amounts of tungsten that are added, work in a synergy to
provide corrosion protection over a wide range of environments. These
alloys depend upon the formation and the tenacity of a very thin oxide
film, chromium-oxide type of a film, on the surface for their corrosion
resistance. We refer to that as a passive corrosion layer. It forms
spontaneously and it\'s quite tenacious.

There\'s a lot of large equipment that\'s been made of Alloy 22. One of
its attractions, it\'s a very tough material. It has significant
elongation when you try to deform it. It has significant toughness if
it\'s impacted. It doesn\'t crack and break like a glass plate would.
You can form it. You can weld it. You can fabricate it. All these things
are important issues when you\'re selecting material for an important
engineering application. It can be fabricated in several large
structures and components. And I\'ll show you some examples of that in
the next slide. Well, no, I won\'t.

I\'ll talk to you about some of the corrosion resistance now. These are
laboratory tests that are typically done to provide material selection
people with a ranking of materials in various aggressive environments.
The particular data here is for an environment that\'s affectionately
called \"Green Death\" because it\'s extremely aggressive. It\'s a
concentrated sulfuric acid, hydrochloric acid, highly oxidizing by the
addition of ferric and chloride ion, and it\'s a solution that alloy
producers will typically run their materials through so they get a
relative ranking.

Two things plotted here. The corrosion rate, low is good. And the
critical pitting potential, high is good. And what we\'re showing here
is a series of alloys. This is 316-Stainless Steel, Alloy 600, and then
down over here are the alloys of the Alloy 22 class of families, and
Alloy 22 is this particular one. It\'s down where the corrosion rates
here are not measurable on the scale. We\'ve heard some about Alloy 600
and pressurized water reactors, so just call it out here that there\'s a
significant difference in the corrosion resistance of these two alloys.
We\'re not talking about the same class of resistance at all.

The critical pitting temperature is measured in the laboratory as the
temperature below which pitting will not occur. So, if you\'re below
that temperature in this particular environment, pitting corrosion is
not an issue. And so high is good here. And Alloy 22, here again, is
this alloy. It\'s at 120 degrees or higher, the solution breaks down at
120 degrees. So, the pitting corrosion potential of Alloy 22 in this
environment is greater than 120 degrees. These are highly acidic, highly
oxidizing environments. Next slide.

This is just a couple slides to show that large engineering structures
have been made and function well out of Alloy 22. Here\'s a fellow
standing next to a component out of a pulp and paper bleach plant. This
was made back in the late \'80s of Alloy 22. There\'s a lot of welds in
this structure. There\'s a lot of forming in this structure. It\'s been
exposed to oxidizing chlorine dioxide, highly oxidizing chloride
containing environments, and it\'s performed very well. The alloy has
been used in incinerators and other conditions where you can get
condensation and dry, wet and dry, and so forth. Next slide.

We think one of the very relevant pieces of experience, in addition to
being a very large structure, this is a flue gas desulfurizer. Flue gas
scrubbers are the units that are on fossil-fired power plants. After the
coal is burned or the oil is burned, there can be sulfur compounds and
nitrogen compounds in the gases. Before those are released to the
atmosphere, the power companies, if they\'re good citizens, run through
a scrubber\--and most of them are\--run through a scrubber and it\'s a
counterflow. The corrosive gases are coming up through the scrubber.
Water solutions are coming down. And so you\'re leaching out or pulling
out of the air solution the sulfur containing gases and the nitrogen
containing gases.

Coal has a lot of sulfur and chloride in it. The temperatures in this
unit are from 80 to 130 Centigrade. Concentrated chlorides and Alloy 22
has provided admirable service in this environment over a large number
of years. So, large structures, large high-corrosion resistance, can be
obtained with these alloys. Next slide.

Let\'s revisit Yucca Mountain from a corrosion perspective. Some of
these slides are familiar, but I\'d just like point out a few things.
We\'re talking about a repository that\'s under some 300 meters of rock
from the surface. Another 300 meters or so down to the water table. The
alloys sit up in air at atmospheric pressure. The relative humidity,
depending upon the time/temperature, can range from very low values up
to saturation. The ambient waters in the mountain are dilute; however,
those ambient waters can be modified and become concentrated by the
thermal hydrological chemical processes that we\'ve heard about earlier
today and yesterday. Next slide.

There\'s some interesting features here. Compared to almost any other
engineering application that I\'m aware of, this is one long, slow
cycle. There\'s no start up and shut down. There\'s no\--it\'s a very
slow heat-up, years, and then a very slow cool-down, thousands, tens of
hundreds of years, thousands of years.

The waste packages sit up in air. They\'re supported by pallets.
There\'s no feasible likelihood that they\'re ever going to be fully
immersed in an environment, in a solution of water. That\'s a big
difference. There\'s no rapid heat\--there\'s low heat fluxes. It is a
hot surface, but the heat fluxes are low. There\'s a slow heating and
cooling and relatively modest thermal gradients. You\'ve seen this
behavior. This is a typical package plotting temperature and relative
humidity and what we\'re showing is over a time on a log scale. This is
10 years, 100 years, 1,000, 10,000, and so forth out to very long time
periods.

When the repository is closed after 50 years, there\'s a heat-up and
then a very long, slow cool-down. On this plot, we\'re showing both the
temperature of the waste package and the temperature of the drift wall.
There\'s a matching drop in relative humidity as a heat-up period, and
then it comes back very slowly, as well. There\'s a limited amount of
water moving through the rock, and there\'s a limited amount of salts
and minerals available to the packages. Next slide.

We\'ve talked quite a bit about relevance of corrosion test methods.
This is just to reiterate that point. Within the drifts, the waste
package drip shield, there are natural convection currents both in this
dimension and also along the waste package, so there is air movement in
here. The thermogravimetric analysis experiment that\'s been run at
Livermore is run in this sort of matter. It\'s an open system, air
circulation, controlled temperature, controlled relative humidity, and
you can follow a process through that, as opposed to a distillation and
reflux condenser where the materials are boiled and captured and then
can be carried over into another experiment.

A closed system, refluxing, 100 percent relative humidity, we believe
this is much more representative and relevant to these conditions. This
is interesting to create solutions and some horror pictures of
corrosion, but we think it\'s not very relevant to Yucca Mountain. Next
slide.

One of the major challenges in Yucca Mountain is this extremely long
time frame. That\'s what\'s unprecedented in this particular
application, trying to predict behavior of materials over thousands of
years and 10,000 years and beyond. And one of the things that\'s very
important though, and hopefully one of the take-away messages for all
the folks here today, is that it\'s important to recognize what the
temperature/relative humidity chemistry solutions are at different time
periods in that repository. We have a tendency to do a test in a beaker,
and if it comes out good or bad, whatever the results are, to mentally
adopt that over a 10,000-year period. Well, it\'s very unlikely that
those conditions in that teacup are going to exist over that time
period. And so we\'ll show you some of that.

There\'s five relevant periods here. Show you the next slide. Well, let
me just say that the\--this corrosion resistant material, as long as the
waste package has no penetrations in it, the radionuclides are
completely contained. All right?

A passive metal, the passive corrosion rate of a metal, is a micron per
year, a millionth of an inch per year or less than that. Measured
corrosion rates are on the order of .01 microns per year. The waste
package at Yucca Mountain is 12-quarters thick. We\'re not talking about
a thin-walled structure here. This is a thick plate of material. Two
centimeters is 12-quarters thick. At this corrosion rate to go through
the thickness of one quarter would take a 160,000 years. At .1 microns
per year to go through the thickness of a quarter would be 16,000 years.
So, passive metals that remain passive, talking about extremely long
lives, is not unrealistic at all. If they\'d have made mummies\' noses
out of Alloy 22, we would find them nice and shiny, okay? But the
Egyptians weren\'t quite that advanced. Next slide.

So, what is the corrosion rate of a passive metal, Alloy 22? Let\'s show
you some laboratory data. Next slide.

A lot of testing done in a lot of large equipment and smaller laboratory
equipment doing electric chemical tests, a lot of tests done on many
samples, different conditions, over long time periods. The long-term
test facility has had thousands of specimens run through it in periods
of excess of five years. Next slide.

The general corrosion rate, the passive corrosion rate, has been
measured by various techniques; weight loss measurements,
electrochemical measurements. The electrochemical measurements are very
valuable and useful because you can look at a wide variety of
environments. Also, they\'re useful because they give you results
quickly. One of the features is the electrochemical measurements,
typically short-term measurements, give you a higher corrosion rate by a
factor of 10 or 100 than what a longer term test would be. But they\'re
still quite useful and valuable. Next slide.

Some range of corrosion rates. In a thousand times the dilute waters in
the mountain, this particular water had .8 molal chloride, .4 nitrate,
at 90 Centigrade, pH 2.8, the short-term corrosion rate was 1.5 microns.
After a week, that had dropped down to 0.1, 16,000 years per quarter. In
the pH 2 solution, short term, one hour test, 2.1 microns per year.
After 30 hours, that dropped down to .2. So, the corrosion rates we
measure in these types of environments are extremely low. Next slide.

This is just from the long-term test facility. As point of reference,
this is that .01 microns per year. That\'s 160,000 years per quarter.
And at 60 degrees and 90 degrees in a variety of waters, pH 2.8, pH 10,
pH 11 to 13, we see very low corrosion rates after very long times. Next
slide.

This just shows some more laboratory data. This is electrochemical data
so that the rates are going to be a bit higher than they would be after
longer times. Here is in nitrate chloride environments and calcium
chloride. And what we find is in a wide range of calcium chloride, .05
ratio of nitrate-to-chloride, .15/.5; the corrosion rate is over the
range of 100 to 160. This is some of the new data that you\'ve been told
about. The nitrates are, in fact, effective inhibitors. The corrosion
rates in general corrosion are very low in this.

This is sodium chloride brines. And, again, the corrosion rates we\'re
measuring here are extremely low, .4 microns per year across here. And
it\'s a function of some of the nitrate-to-chloride ratio. Next slide.

This is some new data to the Board. Again, I believe this is data from
foils that were exposed in an autoclave, so we could go to higher
temperatures than you would be able to attain at Yucca Mountain with
these. They would boil off naturally at Yucca Mountain if you tried to
do it. Exposure times of 130 and 157 days and, again, the major point
here is the corrosion rates are extremely low. There\'s no significant
general corrosion of Alloy 22 in these saturated brines over the range
of 120 to 220 degrees in these tests. Next slide.

So, the conclusions regarding passive corrosion in a wide range of
temperatures to 160 and above using pressurized autoclaves to be able to
maintain those environments, the corrosion rates are very low.
Short-term tests, 2 microns per year and dropping down into this .1 or
.01 range, and less even, after longer time periods. Nitrates show some
benefit even. The primary benefit we\'re going to be discussing with you
is in localized corrosion, but we find the nitrates are of some
assistance in this passive corrosion as well.

All of the different test methods we use, the linear polarization, the
coupon studies, the long-term test facility, give the same message. The
corrosion rates are very low, and they\'re very stable over wide ranges
of material\--of environments. Next slide.

Okay, so the point of that was passive metals remaining passive give
very long lives, and Alloy 22 is a passive metal under an awful lot of
realistic conditions at the environment. So, why don\'t we, you know,
stop and go home? Why do we spend a couple days here and all the
wringing of teeth and gnashing\--or wringing of hands, I guess. You
wring hands and gnash teeth; right? But the point is this localized
corrosion, again. Where does the passive film break down? Where are the
boundaries? What environments do you have to go to? The State of Nevada
has shown us some environments where, no question, Alloy 22 behaves more
like Alka-Seltzer than it does a structural material.

Our argument, our rational is, those are unrealistic and irrelevant
environments. You can put Alloy 22 or any other material in some
environments that will cause very significant corrosion. The question is
will you form those on waste packages, will they persist on waste
packages, will they damage the waste packages? The Project has examined
localized corrosion of Alloy 22 over a very wide range of aggressive
environments, beyond what we believe is the realistic environment, and
I\'ll show you some of that data here now, after we talk about, a little
bit about, the corrosion perspective.

We\'ve talked about, and several of the speakers have mentioned, the
various factors that protect against corrosion. There\'s a hierarchy of
protection here. The thermal barrier stops dripping onto the waste
package. The capillary barrier stops dripping onto the waste packages.
The drip shield stops dripping on the waste packages. If the thermal
barrier was not functioning, the capillary barrier was not functioning,
and in a co-location with that the drip shield was not affected, then a
drop of water can hit on the waste package. And now that\'s what we\'re
going to be studying. But keep in mind here that that can only happen
when the drip shield, the capillary barrier, and the seepage occurs
co-located. Next slide.

There\'s no large accumulation of water that\'s formed in the
repository. We\'ve said this before. The fractures go from a low
percentage of saturation to a higher percentage. There\'s a small
fraction of the packages even in the absence of any drip shield that
would get dripped on. If they get dripped on, the amount of water
that\'s available is very small. This neglects the thermal barrier.
During this time period, the thermal barrier would be in place and this
is zero. If the thermal barrier wasn\'t there, with the infiltration
rates during the current climate, it would be about two liters per year.
Carl explained to you the rational for having to reconcentrate that. It
would give about two milliliters per year per waste package.

After the first climate change, we get about 20 milliliters per year of
concentrated brine, and then it goes up to 40. Again, just a frame of
reference here, 15 milliliters per year is a tablespoon of solution on a
waste package. Okay, we\'re not talking about large volumes of solution
at all. Next slide.

There\'s two relevant time periods. Carl talked about deliquescence in
the morning and dripping and seepage in the afternoon. That\'s why we
broke up the talks that way. What happens during deliquescence and
condensation? That\'s when the dust particles on the package, as the
temperature drops, the relative humidity comes up, as the temperature
rises, relative humidity moves, we can start forming moisture in those
dust layers. And we\'ve talked a lot about that. And then the other
issue is what happens on dripping and seepage.

The considerations here, and we\'ll walk you through some of these, are
what\'s the evolution of the environment? The waters on the waste
package surface are what\'s critical here. That\'s what\'s going to make
or break the corrosion behavior. The evolution of damage, then,
underneath that\--the evolution of corrosion damage in environments that
may cause damage: What\'s the likelihood? What\'s the extent,
distribution? And, so what? What are the consequences of that corrosion
damage? Next slide.

Okay, so you\'ve seen the temperature curves for the waste package and
the drift wall. There\'s a temperature difference between those
depending upon the particular package. You\'ve seen the relative
humidity. Next slide.

Carl showed you this slide. But yesterday in one of the Center\'s
presentations and the NRC data, they chose to break the periods up. I
think they had four periods. But the rational here is pretty similar,
and let me tell you how we define the four periods.

The first period is the preclosure, and that goes from the time that
waste packages start being put into the mountain to 50 years. So that\'s
the first time period. That lasts 50 years. At 50 years, the repository
is closed; the temperature starts to rise. And so we define the second
period that goes from a period of on the order of 10 or 15 years. So,
that would be from 50 to 65 years. That\'s the heat-up period.

We then have a thermal barrier in place. The drift wall is greater than
the boiling point, and so no seepage will occur and the package is cool.
That\'s the Period III. In this particular scenario, that lasts from
like 65 to 750 years. At 750 years, the drift wall is at the boiling
point, and so seepage is possible. So, the Period IV here where seepage
is possible, dripping on the package could happen, goes from 750. And
when the package is at 90 Centigrade, that\'s what I\'ve defined as the
period below which no corrosion of the waste packages will occur.

Why 90? There\'s some data from the Center that was published that said
the critical temperature for crevice corrosion of Alloy 22 was 95°C.
Below 95, they did not see localized corrosion. In some more aggressive
environments, they saw localized corrosion down to 80. Okay? So,
where\'s the right\--where\'s the right number? I showed you critical
pitting temperatures for Alloy 22 that are above 120 Centigrade. And we
will argue, we will tell you, that the conditions on the waste package
are some place between that crevice critical temperature and the pitting
critical temperature.

We do not believe that the critical crevice temperature with
laboratory-made type crevices is the\--that\'s an ultra conservative
measure of the lower corrosion. We could debate that, okay? But if you
pick 90, the things that define these periods are the temperature where
the waste package gets to below boiling, 96; when the drift wall is
below 96, we can get dripping. In this case, the waste package is 101.
There\'s a five degree difference between the waste package and the
drift wall.

The critical temperature here we picked is 90°C. So, those are three
values you need. You need the time when this occurs, and that
temperature, and then you need the time/temperature behavior. Next
slide.

So what are we\--what do we think is going on during these time periods?
During this first period, the ventilation is occurring throughout this
period. The waste packages are cool. Dust can accumulate on the waste
packages and will. That can be dust from the other mining operations and
also ingested dust from the insulation. The metal surfaces are dry.
There\'s no corrosion during that first 50 years. Next slide.

During the heat up period, the drift wall has been dried somewhat from
the ventilation period. There\'s a dry zone from the ventilation. Once
we get heated up, we\'ve got the thermal barrier in place. The capillary
barrier is in place. We\'ve got a highly corrosion-resistant alloy. No
dripping or seepage during this time period. The dust that\'s on the
waste package when the walls are sealed defines the amount of dust
available to this. There\'s no new dust sources from external sources.
There could be minor amounts of dust generated if the drift\--if the
drifts collapsed a bit, but that\'s a small amount of dust material. So,
when you close up the waste package, you\'ve basically got a fixed
amount of dust on it, and that\'s what you have. So, no or none, no
negligible, corrosion at that point. Next slide.

Period III, thermal barrier is in place. We could get deliquescence.
We\'ve gone through the arguments that calcium chloride is a highly
unlikely material. If it\'s there, it\'s unstable. There\'s nitrates in
the dust. During this period when there can be no dripping on the waste
packages, the judgement is no significant corrosion. From 750, in this
case, to 1325\--excuse me, from the 65 years out to 750 years. Next
slide.

In this case now, the drift wall is down to boiling. Dripping and
seepage could occur. We still have those other barriers in place, but
it\'s possible that they could impact the waste package. And there\'s a
time period from that 750 years until 1375 years here when the waste
package is at 90°C, and that\'s what I\'ve chosen as the cutoff for
corrosion. If you push that 90°C out to lower temperatures, you extend
this period somewhat in a lower temperature environment. Next slide.

Period V, the waste package surface is now below a temperature at which
any significant corrosion will occur. You go back to the passive
corrosion rates. Whatever condition the waste package is at that point,
you start corroding. And if that was this .1 micron per year, we\'re
talking about many thousands of years to penetrate the thickness of one
quarter. Next slide.

Okay. So, summarizing that, in the preclosure period, zero to 50 years,
the packages are dry, no corrosion. In the heat up period, no
significant corrosion. By no corrosion here, I mean nothing that would
be of significance from an engineering standpoint. I don\'t want to
split hairs on do you get a pit in the package or do you get some
shallow penetration? There\'s nothing there that would compromise the
waste package in any way. Thermal barrier is in place, no corrosion.

The focus then becomes in this Period IV that requires some more
analysis. We\'re talking about a period of on the order of 600 years for
that particular scenario. And then you come out of that period after
1375, in this particular scenario, and there\'s no corrosion again. So,
the focus of the analysis is in this area. Next slide.

LATANISION: Joe, just to ask a question of information here. Are you
referring to the EPRI fault tree?

PAYER: No.

LATANISION: What are you referring to?

PAYER: We have our own.

LATANISION: Oh, you do? Okay.

PAYER: And I\'ll show it to you.

LATANISION: Thank you.

PAYER: We\'ve got two, in fact.

LATANISION: Okay.

PAYER: Next slide.

So, let\'s talk a little about this localized corrosion process. First,
I\'m going to talk some about the controlling parameters and what we
know about localized corrosion as a process. And then I want to walk you
through and talk about some of the experimental measurements. A lot of
the experimental data in this is going to be new to the Board from what
you\'ve seen in the past. Next slide.

This is just some framework here. When we talk about corrosion, again,
this gets back to the idea that corrosion is driven by the environments
that could occur and by the susceptibility of the material. If there\'s
no overlap between those corrosive environments and the susceptible
material, localized corrosion won\'t occur, okay? If they overlap, then
it\'s only those environments that overlap with the resistance of the
material that are potentially\--that could cause localized corrosion. We
determine those in laboratory tests, typically. We run accelerated
laboratory severe-corrosion tests to determine where these regions are.
Once you have a region like that, though, there\'s additional
requirements in order for that to occur.

At the waste package, you\'ve got to get water in contact, of that
solution type, with the waste package. It has to stay in contact with
the waste package. The corrosion species have to be present to form that
electrolyte. The material is susceptible. And those have to persist over
a long enough time to cause damage. Next slide.

At a high temperature, the packages are dry. So there is no overlap
between there. There\'s no potential for localized corrosion when the
waste packages are dry. When the waste packages\--this is lower
temperature here, schematically. When the waste packages are below this
critical temperature, I picked 90 in the examples I\'m showing here,
there\'s no overlap. So, you get below 90, there\'s no corrosion. You
get in the dry area, there\'s no corrosion. This is just another way to
say that the area of interest for analysis that needs a bit more
analysis, more analysis, are these intermediate temperatures from the
point where you could have wet packages and it\'s above the critical
temperature. Next slide.

This is just a set of cartoons that say this family of environments
could really be broken up into a subset of families, and those
sub-families will have different corrosion corrosivities. Ambient waters
would be farthest to the right, the least benign\--I mean, the most
benign. The more aggressive halide environments move it over in this
direction. And so as the environments become more aggressive, you move
this direction. But by the same token, the metal, the Alloy 22 or the
different alloys, can show different classes of behavior. Next slide.

This is just a montage of pictures here. There\'s a lot known about the
chemical, electrochemical, metallurgical processes that go on for
localized corrosion. We\'re not going to go into them in great detail
here, but it\'s a process that\'s been highly studied and pretty
well-known.

This just shows that different metals have different susceptibility to
corrosion. In this particular oxidizing-acid environment in laboratory
tests, Alloy 825 did not fare very well, high corrosion rate. Alloy 22
and titanium showed no corrosion whatsoever. And you\'ve seen some and
you\'ll see some more of these polarization curves which is a laboratory
method that can be used to exam susceptibility and behavior to localized
corrosion. And from these curves that, in general, will look like this,
there\'s a couple important features.

The corrosion potential is the natural potential of the metal in that
environment. It\'s polarized up through the passive zone where the film
breaks down. This is the pitting or breakdown potential. We then reverse
the potential and look for a hysteresis loop. And where it comes back
across here is defined as the repassivation potential.

The importance of that is, if the system is operating below this
repassivation potential, even if the passive film is broken down by some
random event, it will repassivate and reform. The rationale is, if you
break the passive film in this region above the repassivation potential,
you could see some significant damage before repassivating or you may
not see repassivation, at all. And so that\'s the rationale. We can go
in the laboratory and measure these potentials. And that\'s one of the
key features we\'ll be showing. Next slide.

What controls this passive corrosion corrosivity? The chloride
concentration, temperature, the oxidizing potential of the metal
surface, the severity of the acidity, and the crevice geometry. How
tight is the crevice? What\'s it made of? Fluoride, temperature, and
potential. Higher is bad, more corrosive, more likely to start localized
corrosion. Lower pHs, more acidic conditions are bad, and tighter
crevices are bad. So, in a nominal sense, we know what controls this
process. The question is where are we with this alloy in waste packages?
Next slide.

And this is just a cartoon of a metal. In this case, there\'s a
metal-to-metal crevice formed. This is at high magnification where metal
squeezes against metal. What we find is, if the environment back in the
crevice can become more corrosive, more conducive to corrosion, and
there\'s a lot of factors that affect that. Next slide.

I want to talk a little bit about localized corrosion, the process from
initiation, propagation, stifling, and arrest. In order to go, localized
corrosion has to start. That\'s the initiation process. Once it starts,
there\'s a propagation. What\'s the penetration rate as it starts
working it\'s way through the metal? In many systems we find that the
rate is not constant, but, in fact, it slows down with time. And the
word, the term, that\'s used for that is \"stifling\". The rate gets
slower and slower. It stifles. And in some cases, it arrests. Okay? This
is both the material and an environment condition. And so it\'s
important for us to look at this localized corrosion. Once it initiates,
what\'s the propagation, stifling, and arrest?

And there\'s several things we want to look at here. We\'ll talk a
little bit about this Logic/Fault Tree, about getting it going in the
first place. And then things that affect the propagation and stifling
are things like what\'s the crevice made of, what\'s the severity of the
crevice, what\'s this critical crevice chemistry that has to be
maintained in order to keep the localized corrosion going, and then what
sort of growth rates do we typically see for penetration? That\'s really
the bottom line is what\'s the damage evolution? Next slide.

A comment on crevice formers. In the laboratory, we formed the tightest
crevices that we know how. And the way that\'s done is with a piece of
Teflon, PTFE, the generic name for it, but you take a piece of this
polymeric material and you squeeze it tightly against a metal surface.
That forms as tight a crevice as we know how. The liquid still gets back
in there. If it didn\'t, we would have no problem.

The liquid is in there. If we try to form that same crevice by squeezing
two metals together, because of the surface roughness of the metals,
even highly polished metals, we can\'t form as tight a crevice as we get
with these Teflon-type crevices. If you form a rough ceramic, a piece of
rock or something, against the surface, you get even a less severe
crevice, and that will be reflected in the temperature at which crevice
corrosion will occur and also the severity of the environment. And so
one of the things that we will argue is that crevices do not exist over
the great extent of the waste package surfaces.

There are crevices on every package, but we do not believe dust is an
effective crevice former. We\'re not sure that rock is an effective
crevice former. The metal-to-metal crevices that can occur are effective
crevices, but they\'re not as severe as our laboratory tests. So, it\'s
an important point to keep in mind. Next slide.

Critical crevice chemistry, if you get\--these are ranked in more
corrosion resistant alloys; a ferritic stainless steel, a couple
austenitic stainless steels, 625. As the corrosion resistance of the
alloy increases, the solution, the acidity and chloride necessary to
drive that localized corrosion process, becomes more and more severe.
The acidity has to become greater, reflected as lower pH values, and the
chloride concentration has to increase.

Alloy 22 is even more corrosion resistant than Alloy 625 here. So, even
a more severe solution has to be formed and maintained in that crevice
in order to continue localized corrosion. Next slide.

In the growth, what do you we see typically in growth of crevice
corrosion? The penetration rate, the rate at which we\'re going through
the thickness of this plate, in the case of the waste package, typically
follows a behavior where that penetration rate is timed to an
exponential power and a pre-exponential term here. This end value tends
to be between .1 and .5. And the important significance of that is shown
schematically in the next slide.

The corrosion rate doesn\'t start and maintain at these very high rates
that we can often seen initially. But, in fact, a corrosion rate bends
over, and the lower that value of N, the quicker and the lower value at
which it starts getting asymptotic here. So, this is just a schematic
here where N equals .1, .3, .5, but the main point is we don\'t maintain
these very high initial rates for very long. The corrosion rate
decreases. Next slide.

Okay. So, localized corrosion\--localized corrosion fault tree here, if
we have a corrosion-type of water that will cause corrosion, if that
water can form and the metal is susceptible to it, and we measure that
in our accelerated severe laboratory tests, if conditions A and B are
there, is the corrosion rate positive enough to be above that
repassivation potential? If the material is susceptible, the solution
can maintain localized corrosion, you still need an oxidizing potential
above that repassivation potential or else you won\'t get localized
corrosion. We do it in a laboratory with a black box, with an electrical
box, a potentiostat, where we force it up into that region.

If the corrosion potential is positive enough, you\'d need a severe
enough crevice on the specimen. In the absence of crevice, you would not
get localized corrosion. If you\'ve got A, B, C, and D, then you go
to\--you can initiate localized corrosion. The question is what\'s the
damage evolution? How long will it go? What sort of stifling and arrest
might you exhibit?

So, the questions we have here are, the requirements for damage are, do
the conditions exist, will corrosion occur, will it persist, and what
damage might be the result? And we want to look at those at the five
different periods in the repository to determine under which of these
localized corrosion might be an issue. Next slide.

Okay, let\'s talk about some experimental measurements now. Next slide.
This, again, is just a picture of a laboratory at Lawrence Livermore
where a lot of the testing is done. The specimens are metal specimens.
Here\'s the crevice formers. These things are bolted together. The tight
Teflon-seal against the metal is then put into an electrochemical test.
Several different tests are used. This shows data for a typical cyclic
polarization which has been used extensively by the Project.

There\'s a Tsujikawa\--there\'s this guy, THE experiment. I have to get
Raul to say that at every one of our review sessions here. But that\'s a
more severe test where you break down the passive film and then you step
the potential back to see where it arrests. Okay? But essentially the
kind of ranking and the kind of behavior you get are very similar in the
two results. The THE test is somewhat more severe. Next slide.

Carl mentioned to you the different categories of water, and what I\'d
like to do now is go back and we\'ll talk about the localized corrosion
behavior in these different types of water. The source of the different
waters are the chemical divide theory and other processes that Carl
summarized for you. The ambient waters are dilute, multi-species.
They\'re near neutral, but as you go through those dilute waters and
they become more concentrated, you can go into carbonate brines,
sulfate, and so forth. And so the question here is what sort of
corrosion behavior do we observe in that? Next slide.

So, let\'s talk about the dilute waters and the carbonate waters. And
the picture here is pretty boring from a corrosion standpoint. These are
not corrosive waters. Alloy 22 is benign in those environments. If you
were selecting a material for an industrial application and these were
the waters, you would never select Alloy 22. You don\'t need that high a
corrosion resistance. If we were assured that the waters in Yucca
Mountain were always in this environment, we wouldn\'t be talking about
Alloy 22 packages. So, these environments are noncorrosive, the dilute
waters and the carbonate waters, no localized corrosion. And this just
shows one of the polarization curves. You go up. There\'s no hysteresis.
Not very exciting. Next slide. We don\'t want to be exciting,
particularly, but that\'s the deal.

Okay. What happens, we\'re going to talk about the family of waters that
are\--this family of waters, the sulfate brines and the
sodium-potassium-chloride-nitrate brines. Major distinction here is can
some calcium magnesium be present or so forth? But these are the waters
we\'re talking about. In these waters, the summary is that we find that
the waters with modest amounts of nitrate, we see no localized
corrosion. Not observed. It\'s not observed on welded specimens in the
long-term test facility and it\'s also not predicted by our rapid
electrochemical forward and reverse tests.

Waters that have low nitrate levels can have the possibility of
initiating crevice corrosion when they\'re polarized into this
susceptible zone. One of the things I\'ll show you on some of the
specimens when we do that, when we initiate crevice corrosion
artificially by polarizing into that region, that the initial high
current penetration rate drops off markedly so we do see stifling under
some conditions. Next slide.

LATANISION: Joe, just to get another point of information, are you
referring to experiments in which you\'ve got a artificial crevice
present or\--

PAYER: These are laboratory, the cyclic polarization with the crevice
formers on the specimens, the standard tests. And some of these have
been backed up with the THE method. So, there\'s been a collaboration
between them. Next slide.

Just an issue on some of the solution chemistry, again. You\'ve seen a
lot of this already. Just the straight time/relative humidity, there\'s
inaccessible regions here. So, this whole region can be taken out as
possible temperature conditions at Yucca Mountain. Solutions won\'t
exist up there. It\'s above-boiling. We talked about the eutectics here
and that has a big affect on the nitrate chloride. We\'ve talked about
the deliquescent points of the various salts, and what that led to is
this diagram that Carl showed you that said, okay, for
sodium-potassium-nitrate-chloride-type brines, any condition below this
line, any temperature/relative humidity are going to be dry salts, no
corrosion.

Any condition out here is going to be inaccessible from
temperature/relative humidity. The waste packages will be dry. And so
the question is, and if we\'re in this region, the nitrate-to-chloride
ratio will be greater than .5 because of this type of behavior. Up here,
we can get into the lower nitrate/chloride type brines, and then
sulfates come in here. So there\'s a rationale for where we exist on
time/ temperature\--next slide\--for these solution chemistries.

Let\'s talk about the nitrate inhibition of\--these are samples that
contain welds. The specimen was a plate specimen that had a section of
weld through it. And then the crevice formers were formed so that some
of the crevice feet were over weld material and some of them were on
base plate. So, it was a heterogeneous specimen from that standpoint.

And what comes out of this, this is an eyeball test, but you can see the
data in your handouts. The message that comes out of this, and this is
data at 80 degrees and 100 degrees, if the nitrate-to-chloride ratio is
greater than .5 at 100 Centigrade, we saw no localized corrosion. If the
nitrate-to-chloride ratio was greater than .15 at 80°C, we saw no
localized corrosion. Okay? So, that puts a boundary on the
nitrate-to-chloride ratio. You need less nitrate at lower temperatures,
it\'s less severe. Next slide.

This just shows that, in a cartoon here, this is the repassivation
potentials versus the nitrate-to-chloride at 100 Centigrade. When we get
up to this .5 ratio, we get a very positive repassivation potential.
That\'s good. At lower nitrates, it\'s down around where the corrosion
potential could be, and we could have conditions that would promote
localized corrosion. At 80 Centigrade, at the .15 value, we\'ve already
transposed\--moved into this high repassivation potential. The data at 1
molar, 3.5 molar, 6 molar chloride are all basically the same. The
chloride in these tests didn\'t have a significant affect on the
behavior.

Long-term corrosion potentials start reaching the Ecrit in these low
nitrate-to-chloride. Sulfate can be beneficial under some circumstances.
Next slide.

This compares\--a bit of a busy slide, but the couple points here\--as
you go up in chloride concentration, the repassivation potential comes
down. And so from a\--that\'s not a good thing. Okay? The more it comes
down, the more\--the easier it is to get up into that region. So, again,
it takes high chloride to do that.

The other point here though is these triangles. These are data from the
Center, NRC\'s laboratory folks in San Antonio. And you\'ll see that
they\'re consistently higher, their repassivation potentials, than
what\'s been measured by the Livermore folks at DOE labs by both these
methods; the cyclic polarization and this Tsujikawa method. Tsujikawa is
a bit more severe, but they\'re about the same. And one of the ways of
rationalizing this is the test procedure that Livermore uses forms a
tighter, more severe crevice than what\'s formed by the Center. And so
we think there\'s a logical rational reason for seeing this offset here.
It\'s a bit of a secondary issue, but it does get back to this point
that it\'s important about what makes the crevice. Next slide.

Okay, so now we\'re going to talk about these waters here, and we\'re
talking now about the high nitrate chloride brines, the more
concentrated brines. They\'re restricted into these types of
environments. And what we find is that when there\'s high nitrates, we
see no localized corrosion. This 115 Centigrade, this test here where we
do the polarization curve, and we see no evidence of susceptibility to
localized corrosion, that\'s at 115 C in a concentrated fluoride/nitrate
environment. That\'s as concentrated as you can get and still have
moisture, okay? So that represents the very first sort of deliquescence
in those environments or it represents the very last dry-out drop. And
the point is, if the nitrate levels are up, we don\'t see corrosion,
localized corrosion susceptibility. Next slide.

This is a case where we do, in fact, see a hysteresis loop. This is a
concentrated chloride nitrate at 100 C. In this case, the corrosion
potential is well below the repassivation potential. In a long-term
static corrosion test, we would not expect localized corrosion because
the corrosion potential is below the repassivation. If we, with a
laboratory instrument, polarize up to 100 millivolts to force localized
corrosion to start, we measure the current as a function of time and
currents going up is not a good thing. Currents going up means the alloy
is corroding. And so what we find is when we polarize up into this
region with our potentiostats, the current increases, but then with time
it drops off significantly in the presence of nitrate. And so in this
particular set of environments, nitrate is not only effective at higher
levels of preventing localized corrosion from starting, but it\'s
showing a stifling or an inhibiting effect.

This process of stifling and initiation is really an area of active
research and active needs and getting better descriptions of just when
that occurs. But in this case, certainly in these types of environments,
we see evidence in this example of stifling occurring. Next slide.

Gets us to the calcium-magnesium-chloride-nitrate brines. We spent a lot
of time talking about that. Ron wonders why, now. We didn\'t know why
when we started into those tests and all, and so it was important to
establish the behavior. We\'ve beat on this all day long, so you know
the message here. You can choose acceptance of it, but the chemistry is
pretty clear. Calcium-magnesium-chloride-nitrate brines are highly
unlikely in the repository. If you don\'t believe that or if you just
want to know what would happen if they did exist, these experiments were
done. Next slide.

In concentrated calcium chloride brines, the nitrate-to-chloride ratio,
again, is effective at high temperatures. This is 160 degree data. These
are the highly concentrated, first deliquescent-type brines, calcium
chloride, if it were to exist. And at high nitrate values, it\'s still
effective at stopping localized corrosion. At low nitrate, you could
have some corrosion occurring if those environments could persist. Next
slide.

And this just\--this is passive corrosion rates here, but I just want to
go back and remind you that nitrate is very effective at temperature
ranges between 100 and 160: low, passive corrosion rates. Next slide.

Okay. The focus is on this Period IV that we\'re calling it. When the
waste package\--when the drift wall is below the boiling point, it\'s
possible to get dripping seepage from the drift wall if the waste\--if
the drip shield is not there, capillary barrier is not there, if it hit
a waste package, what would happen? Several considerations during that
period. The first is, is the capillary barrier or drip shield, are they
effective? If they\'re not effective, then over what area will seepage
and distribution occur? What\'s the composition of waters during that
time period, both the composition and concentration of those waters? How
does Alloy 22 behave in that? And we go through this, what we\'ll call,
the local corrosion fault tree, and then come down into talking about
damage evolution here. Next slide.

We\'ve talked a lot about this medium temperature package. And this
represents a realization of a temperature/time curve, the waste package
temperature. Here\'s the matching drift wall temperature. And here\'s
the relative humidity. This is the hotter package, and this is the
colder package. For this mid-waste package\--medium, moderate waste
package, it enters this Period IV after 750 years and the waste package
surface temperature is 101 Centigrade. Relative humidity is 65 percent.
It leaves that period into a range of no corrosion, defined here by 90 C
in 1375. So it\'s in this region for about 600 years.

The hot package enters that region at 1900. The waste package is at 99
degrees Centigrade, relative humidity 56, and it leaves that period in
3,000 years. So, from the period of 1900 to 3,000 or in this range
temperature of waste package continues to decrease over that time period
until it exits at 90.

For the cool package, we get into that region at 112 years. The waste
package surface is 102 degrees, relative humidity 72, and you would come
out of that in 175. So, depending upon the particular waste package that
you select and its thermal load and history, you can follow these
trajectories. Next slide.

We can take that information, and that\'s what Carl did, to take that
time/temperature history during this critical period. We know the
temperature at 750 years, we know the relative humidity, and that picks
a point over here. So, at 750, this waste package is at 101 degrees, and
the relative humidity is 65. That\'s that point on this diagram. So, you
see what we\'re doing is we\'re matching the chemistry constraints to
the behavior of the waste package, and then we can follow that
trajectory of possible waters throughout that time period. And then we
can relate that back to our expected corrosion behavior. So this
particular package at 750 starts at this point. And then it continues to
cool, moving this direction in temperature. And the relative humidity
continues to rise, so it follows this trajectory. And this is the point
when it\'s at 90 Centigrade, that\'s at 1375. Okay?

So, these are the trajectory of temperature and relative humidity. You
can\'t just pick any temperature, any relative humidity you want. It\'s
fixed. Now the question is what will the salts do, what will the
environment do under those conditions? And the damage that can occur is
damage over that 600 year period. You don\'t have 10,000 years for
damage. You\'ve got this finite amount of time. Six hundred years is a
long time, okay? But it gets much better closer to what corrosion
engineers are sort of dealing with all the time. Next slide.

So, here\'s our crevice corrosion decision tree. I didn\'t talk to Mick
before the conference. I didn\'t know he was going to make a pitch for
decision trees, but we decided it would be useful also. This means no
localized corrosion. If there\'s a thermal barrier in place, no
localized corrosion. We\'ve talked to you already about the noncorrosive
nature of the dust particles on the surface in the absence of dripping.
You don\'t get enough water, you\'ve got high nitrates, you\'re not
going to form calcium chlorides. Corrosion under those deliquescent
conditions and the absence of dripping are not an issue. They\'re an
issue, but they\'re not a corrosion problem, okay?

So, it\'s the dripping conditions that we need to consider. If the
thermal barrier is working, no corrosion. If the thermal barrier
doesn\'t work or we\'re beyond that period, the capillary barrier, if
it\'s effective, no corrosion. If the capillary barrier and the thermal
barrier break down, and in that same area where seepage occurs, the drip
shield is not effective\--or is effective, no corrosion. If you defeat
or have simultaneous co-located breakdown of those three barriers, you
could have seepage onto the waste package. If the seepage on the waste
package is a dilute water, a carbonate water, a moderate nitrate water
of the sodium/potassium mixtures, they won\'t support localized
corrosion.

So, the only way you can get through this whole line is for breakdown,
breakdown, breakdown, seepage occurring at that location and forming a
low nitrate/sulfate brine, and then you can have, you can initiate
crevice corrosion. Will you? Is the corrosion potential positive enough?
Are the crevices severe enough? If they aren\'t, no corrosion. If they
are, you look at evaluation of initiation, propagation, stifling, and
arrest, and you determine the evolution of damage. That\'s the fault
tree that we believe makes sense to go through. Next slide.

So, in this critical period, this time period where dripping could
occur, seepage is possible, and you\'re at a high enough temperature
that Alloy 22 still is susceptible to corrosion, you follow the
corrosion logic fault tree, you use the temperature and relative
humidity, the package, to follow trajectory of the types of
environments. There are thermodynamic solution constraints on the
aqueous phase. The amounts of salt and water and mass balances\--you
just can\'t make up and hope you\'ve got as much chloride as you want or
need. It has to be an amassed balance, somehow, in the water that\'s
coming into there. The same with the nitrate. The mass balances have to
fit. You determine the number of noncorrosive solutions. There are a
number of those. There are some solutions that aren\'t.

When we go through that logic, the conclusion is that massive large
amounts of localized corrosion causing penetrations of waste packages is
not going to happen. We just can\'t see that number and those conditions
persisting over a wide number of packages, wide amount of damage.
Isolated packages may be affected. Okay? We can\'t totally take that off
the table, but we do believe that that\'s going to be a small number, a
small amount. The question then is where and how much? And that\'s some
more analyses, but it\'s an isolated number. Next slide.

Okay, some conclusions. Next slide. They\'re sort of matching a bit
here. At least I thought they might match. In summary, Alloy 22 is a
highly corrosion resistant metal. That\'s confirmed in laboratory
experiments and very harsh environments. It\'s also verified and
validated by industrial experience with large engineering structures
that are welded, that are moved around, that are fabricated, put into
place, and at multi-species solutions, oxidizing. This sounds like Yucca
Mountain, harsh environments.

Yucca Mountain repository conditions, the waste packages sit in air. The
ambient solutions are dilute, noncorrosive, but we\'ve got to deal with
these concentrating factors. Where will they go? What sort of solutions
will they form? Next slide. Okay, we\'re going to change that one, too,
John.

Alloy 22 is a highly corrosion resistant material. And these passive
metals, coming back to here, we\'re talking about a thick structure.
It\'s a plate, 12-quarters thick. That\'s a lot of metal. A quarter of
that at passive corrosion rates will last 16,000 years at .1 microns per
year. So, if it\'s passive and it remains passive, we win hands down, no
question, from a corrosion standpoint. The question then is what about
localized processes? Next slide.

There\'s a hierarchy of factors that prevent corrosion. There\'s a
thermal barrier, capillary barrier, drip shield, and this highly
corrosion resistant material where no drips form on the package. We\'ve
got deliquescent corrosion conditions that pertain and the conclusion is
no significant corrosion damage will occur under those environments.
Limited amount of water, noncorrosive environments, high nitrates, not a
problem. Where dripping can occur, then you\'ve got to evaluate the
types of waters that would pertain in there, and then you have to apply
that to the relevant times periods over which they can occur. You don\'t
have a choice of just saying they\'ll be there forever, or they\'ll be
whatever. They\'re going to be driven by the temperature/relative
humidity behavior. Next slide.

We have analyzed this in terms of five relevant time periods, and we
focused down to determining that the Period IV when the drift wall is
below boiling, the package is above the critical temperature, and when
the capillary barrier/drip shield are not operative in that area, then
we have to analyze the behavior in that. And when we go through that
analysis in our logic/fault tree and so forth, we conclude that there
will be a minimum amount of corrosion. Next slide.

No significant corrosion outside of Period IV. Environments during
Period IV will show a range of corrosivity. There is a subset of those
environments that could support localized corrosion if there were
crevices and other conditions met. Alloy 22 is highly corrosion
resistant in many of those waters. The localized corrosion is restricted
in that time/temperature range. There are several factors that, in fact,
could impede the corrosion rate once it\'s started. So, our overall
conclusion is large areas, no significant corrosion, isolated packages
may be excepted.

Always/everywhere we believe is unrealistic and just not supportable.
Never/anywhere is closer to being what we believe is the case, but we
can\'t say that absolutely. And so, sometimes in isolated spots, we may,
in fact, get that.

Okay, thank you very much. I appreciate your time.

LATANISION: Thank you, Joe. We began by saying we wanted to have a very
full and objective hearing of the issues that were of concern to the
Board, and you\'ve certainly given us a very full package here. In fact,
so full that I\'m sure it\'s going to take some time for us to digest
all of the information that\'s present. But I do have a couple of
questions, and I think I\'ll exercise my prerogative as Chair to begin.
I see these other hands over here, but I\--

UNIDENTIFIED SPEAKER: No, you don\'t.

LATANISION: No, I don\'t. I do want to compliment the Project for really
very fully responding to the concerns we raised. You folks have
obviously done a lot of work over the last six or nine months, or
whatever. And I do want to compliment you and the management of the
Project for following up.

Yeah, right. I mean, there is always a \"but\", but this slide is useful
in the sense that\--maybe it was the previous one, actually. I wanted to
focus on the Period IV segment of the histories. Was it a previous
conclusion?

PAYER: It was this, maybe. John will find it. John\'s a magician.

LATANISION: Yeah.

PAYER: Will this one work, Ron, or do you want the\--

LATANISION: Well, actually it\'ll work. And it\'s in the following
sentence. You\'re basing a lot of your comments on a critical
temperature for localized corrosion of 90 degrees.

PAYER: Yeah, in this example, that\'s what we\'re using. And I gave you
a case for why that is.

LATANISION: Right.

PAYER: But that\'s\--that\'s right now more Payer\'s\--

LATANISION: No, that\--

PAYER: \--example case. But, you know, I\--there is a rationale for
that. The Project has not selected an absolute value.

LATANISION: Okay.

PAYER: And so that is a debatable point, but\--

LATANISION: And that is the point I want to raise.

PAYER: Okay.

LATANISION: I mean, we saw some data yesterday from the Project\--sorry,
from CNWRA that indicated that localized corrosion could occur at
temperatures as low as 60 degrees.

PAYER: And the consequences of that\--

LATANISION: Right.

PAYER: \--were it to be true, would be to move this boundary out to 60.
It would extend the time period and it would extend this trajectory
along that. And so, again, you\'d have to then consider do the
environments stay in a corrosive environment or not?

LATANISION: Right.

PAYER: And, you know, the stifling, arrest, all those\--all those sorts
of things.

LATANISION: Right.

PAYER: But that\'s\--you\'re right.

LATANISION: The question really has to do with the uncertainty in your
choice of a number. And I think in a sense you\'ve already answered
that. It is at this point still an evolving discussion, as I understand
your response.

PAYER: I think so. I don\'t know that the Project has decided to use
that cutoff particularly.

LATANISION: Yeah.

PAYER: Bob can get more into that issue about how they actually work it
into TSPA now. But certainly from a corrosion science and behavior
standpoint, it\'s a real concept.

The other, Ron, as you well know, these environments aren\'t just a
material property. Taking a nitrate-to-chloride ratio at 100 Centigrade,
the nitrate-to-chloride ratio we measure that you need is .5. At 80
Centigrade, that\'s dropped down to .15. And so less nitrates will, you
know, will still save you at that condition. And so, the issue is where
are you in these realistic type environments?

LATANISION: I\'ll buy that. Let me ask one other question. I\'d like to
go to Slide 51.

In the cyclic polarization diagram that you show there, the
repassivation potential would normally, if it were a true repassivation
potential\--I want to understand what I\'m looking at exactly\--when you
have achieved the repassivation potential and you drive the potential in
a more reducing direction, you\--I would have expected to trace out the
passive current density, and yet you show what looks like a cathodic
current density there.

PAYER: Well, I think you do. You start here at the corrosion\--well, the
way these tests are run is you\--Raul, tell us exactly how to test a
run. I mean, but you get a cathodic branch passive current and then so
forth, but\--

REBAK: This is Raul from Livermore.

And, yeah, they\--we start the cyclic polarizations at the potential
below the corrosion potential\--

LATANISION: Right.

REBAK: \--instantaneous corrosion potential. We go until a\--you know,
you go up until a breakdown happens, and then by ASTM standard G-61, we
reverse that to five million per square centimeter, and goes down\--

LATANISION: This is in a crevice geometry; right?

REBAK: This is\--all are crevice specimens, yes.

PAYER: \--this, yeah.

REBAK: We have a specimen with 24 crevice spots on each one.

LATANISION: Okay. Okay.

REBAK: So, and then you reverse and then whenever that

\--the reverse current, it cuts the upright current, we call that
the\--the repassivation potential or the crossover potential. And this
is the data that the Project is using for repassivation potential.

PAYER: You\'re probably used to seeing these people stop plotting it
right here.

LATANISION: No, I\'m just curious\--

PAYER: But if you keep doing that, that keeps running over onto the
cathodic side.

REBAK: Exactly. Exactly.

LATANISION: I\'m really curious about the fact that you\'re\--if you
suppress the potential more to a value that is more reducing\--

REBAK: Yes.

LATANISION: \--you\'re actually see a higher cathodic current density,
and so\--

REBAK: Yes.

LATANISION: \--therefore you\'re plotting a cathodic current density.

REBAK: Yeah, exactly.

LATANISION: That suggests there\'s a pretty markable shift in the open
circuit potential.

REBAK: Yes.

LATANISION: Which surprises me. That\'s a pretty dramatic shift.

REBAK: Yeah, but this is how this technique is done, and, you know, you
always have\--when you have that crossover is because you are achieving
what people call the second corrosion potential\--

LATANISION: No, Raul, to be really clear on this, my experience is that
if you find that the anodic current density remains typical of the
passive current density, you\'re likely to track out the remainder of
the anodic polarization diagram. If you have a very high\--a very high
rate cathodic process, then you begin to see that. And it\--what I\'m
seeing here is a really dramatic shift in the open circuit potential,
far more than I would have imagined. And given the nitrates or
oxidizers, maybe I should have imagined.

PAYER: Dave\--

LATANISION: But I\'m surprised by that.

PAYER: Dave Shoesmith?

SHOESMITH: Dave Shoesmith, University of Western Ontario.

When you take in the polarization tests, when you take the potential so
positive\--

LATANISION: Yeah.

SHOESMITH: \--you\'re actually probably hitting the transpassive region,
which means you are inducing a whole series of defects in the general
passive area at the same time that you are initiating the localized
site. And on the recovery, most of the passive area, the corrosion
potential has gotten much more positive. And, therefore, you see that
effect, stop the repassivation potential, but you also see the very
defective passive film that you have induced by going very close to
transpassivity. I think that\'s what we\--

LATANISION: I hear what you\'re saying, and I don\'t want to prolong
this. I\'m going to need to think a lot more about this because that
surprises me.

David?

DUQUETTE: Just point of clarification. Duquette, Board, a point of
clarification on that.

It\'s the nature of the test, having done several thousands of these for
the Navy not too long ago. The problem is that the test is done rapidly
enough so that you don\'t really repassivate the inside of the crevice.
And so you\'ve\--that\'s your new corrosion potential, which is way up
in that area. And so it\'s because the\--you still have the acidic. If
you stop the test for awhile, as we sometimes have done, let it come
back to some steady state, you will retrace the passive\--

LATANISION: Okay. .

DUQUETTE: \--passive current again.

LATANISION: All right. I\'ll take\--

PAYER: We\'re getting a little detail here\--

LATANISION: Yeah, but that\'s\--

PAYER: You generalists in the audience, we electrochemists get really
excited about all the (inaudible) on these curves. I mean, they all are
like, you know, like our children here. So, we have to\--

DUQUETTE: Yeah.

LATANISION: Go ahead.

DUQUETTE: Duquette, Board, again.

Could you go to Slide 48? I want to clarify something in corrosion
science here. Okay, when you have N equals 0.5, that\'s a parabolic
equation that\'s usually controlled by diffusion through some kind of a
film.

PAYER: That\'s one of the ways it can be\--

DUQUETTE: You\--you\--

PAYER: \--or diffusion out of a crevice.

DUQUETTE: Fine. But you and I both know that if the situation is acid
enough, that you can get an N equal to 1, where your reaction-rate
controlled rather than diffusion controlled. And so this assumes that
you get a diffusion driven process. I don\'t think you do, inside a
crevice that\'s very acid, if the crevice becomes very acid. In fact,
we\'ve got some experimental data that indicates that\'s not true. What
typically happens is somewhat the reverse of that, although for
artificial reasons.

During the initiation period, the corrosion rate starts out slow until
the solution inside the crevice reaches steady state and\--or reaches a
kind of steady state. And then it takes off on a linear basis because
there\'s nothing to cause diffusion in that case. It depends on the
shape of the crevice and a whole bunch of other things.

PAYER: If it does that\--

DUQUETTE: But corrosion rates don\'t always go down in crevices. In
fact, quite often they go up from the time the crevice corrosion
initiates, and they do reach a constant value rather than\--reach a
constant value and then decreasing.

PAYER: Yeah, well, let me just pass it on to Dave Shoesmith because
he\'s done some of\--a lot of this analysis, but\--

SHOESMITH: Well, Dave is quite correct in\--Dave Shoesmith, University
of Western Ontario.

He\'s quite correct that the current will go up when you first initiate.
That\'s generally related to the fact that you\'re activating a wider
area of the crevice, so it spreads. It will, in fact, the current will
go up. But if you hit any kind of IR or diffusion control, which you
have to hit eventually in a narrow geometry, the current has to turn
over the top. And the only way I\'ve ever seen or know of in the
literature where you can get above .5 is if you have an intergranular
attack in a sensitized material. I just don\'t see how you propagate it
for long periods at a linear rate or any rate beyond an exponent of N
equal to .5.

DUQUETTE: We\--

SHOESMITH: I don\'t know of one in the literature other than
intergranular attacked\--intergranular sensitized sites that do that.

PAYER: Dave, are you talking about crevices being driven with a
potentiostat where you\'re maintaining all the cathodic current you
need?

DUQUETTE: No, actually these are crevices driven by a very strong
oxidizer, ozone in that particular case.

PAYER: Okay, fair enough. Fair enough. This a cartoon of that crevice.
And I guess the point here is that what we\'re talking about is
diffusion in and out of this crevice as a potential reason for why these
bend over. We see the same kind of behavior in some pit growth. But
there\'s other processes that can go here. That can. We\'re not saying
universally, but that can affect arrest, stifling, and so forth. And,
again, it\'s going to be a function of the corrosivity of the
environment. But we will say that in a wide number of stainless steel
passive metals that this type of behavior is seen and reported. We\'re
not saying it\'s universal.

DUQUETTE: Duquette, Board, again.

Again, I don\'t want to discuss all the science here, but the fact of
the matter is it depends on the time scale and how rapidly the crevice
sets itself up. I mean, obviously David Shoesmith is correct. Eventually
there\'s going to be some IR considerations or some diffusion
considerations, but they can take very long periods of time, depending
on how long it takes for the crevice to reach some kind of steady state.

PAYER: Fair enough.

DUQUETTE: Now, we\'re talking about samples that are going to be in
place for very long times.

PAYER: Fair enough. The\--let me also just reiterate that this whole
issue of stifling, arrest, initiation, propagation, what are the rates
is an area of active research in the Project, and I anticipate it will
continue.

DUQUETTE: Can we go to slide 22, please? Now, these corrosion rates
aren\'t very high, but a great deal of issue has been made about the
nitrate-to-chloride ratio. And if I take a look at the data at 140, and
I understand that those can\'t exist at Yucca Mountain, but I just want
to point out that the data aren\'t always as neat as they could be
because if I look at the nitrate-to-chloride ratio for the bottom one,
which is 6.7, I have a much higher corrosion rate at the same
temperature and presumably the same environment than I do with a ratio
of .05. And so there, that seems to be a reversal of trend. Even though
those rates are low, there is some confusion, I think, in that\--I
wouldn\'t say confusion, but, at any rate, the nitrate isn\'t always an
inhibitor.

PAYER: Greg Gdowski, is this environment\--that\'s very close to
saturation; right? It\'s 6.7 nitrate-to-chloride total molality of 9.6
at 120\--140.

GDOWSKI: No, I think, it\'s\--

LATANISION: Greg Gdowski?

GDOWSKI: Oh, it\'s Greg Gdowski.

No, I don\'t think that\'s quite the\--

PAYER: Okay, fair enough. Oh, well.

(Pause.)

DUQUETTE: Okay. I think I\'ll pass for right now. I want to think about
some more of my questions.

LATANISION: Okay. Dan Bullen.

BULLEN: Bullen, Board.

Can we just go to figure 26? Just a quick question here. As you take a
look at the seepage water per year per waste package for the time
periods where you take a look at, you know, the 2 liter, 20 liter, 40
liter, that assumes no diversion of water from a hotter to a colder
waste package or any lateral diversion along the drift?

PAYER: Bo? The question was does this take account for any lateral
diversion from a hotter to a colder package or along a drift? Is
that\--did I catch that, Dan?

BULLEN: That\'s correct.

BODVARSSON: Bo Bodvarsson, Lawrence Berkeley Lab.

It does not take that into account. This is just directly seepage.

BULLEN: Thank you. Can we go to figure 67?

Just a quick question. As you track these trajectories with respect to
time, are these trajectories identified for, say, a mill-annealed type
material, or do you have\--would you expect a change for cold-worked or
welded or fabricated materials, or do you think everything would be
almost exactly the same?

PAYER: The trajectory would be exactly the same. Those wouldn\'t change,
I don\'t think, the local temperature/ relative humidity.

BULLEN: Okay. How about performance\--

PAYER: The corrosion\--the corrosion behavior that you then get out of
this would\--that\'s a second step. I mean, this tells you the
temperature/relative humidity, and you\'ve got to go to what the
starting composition is to see where that change is. So, that\'s not
accounted for in here, but it wouldn\'t change this trajectory.

BULLEN: Bullen, Board.

Would you expect it to change performance significantly?

PAYER: It may. There are cases if you, you know, if you age Alloy 22 at
high temperatures, the Center\'s done this on a few occasions where they
heated to\--well, let me\--I\'ll pass the baton to Tammy here. She can
tell you more specifically, but if you artificially age them at high
temperatures, you can cause deleterious phases. What we\'ve found in lot
of these localized corrosion experiments that contained welds is the
welds, if anything, were a bit more corrosion resistant then. But,
Tammy, you want to reiterate the\--the question was when we\'re
following these trajectories, what would we say about performance of
welds or mill-annealed or\--

SUMMERS: Summers, Lawrence Livermore.

Following those trajectories, the performance that you saw today, for
one, all that data was weld data. So, that is the behavior you would
expect for welds. For aging, I think, you know, I could pass the baton.
We don\'t\--because Raul knows better the corrosion behavior or the
response to aging. But we don\'t predict any aging. When you look at the
Center\'s data, the 8-70 for\--five minutes. That‑-that is a higher
temperature phase. That is not\--we don\'t predict to be stable at the
lower temperatures.

BULLEN: Bullen, Board.

Maybe I wasn\'t as explicit as I thought. I guess the question is would
you expect the range for which the corrosion would be a potential
problem with respect to chloride/nitrate ratio to change? You mentioned
the temperature change\--

PAYER: Oh, I see. I see where you\'re going. I guess what we say for the
crevice corrosion, the nitrate/chloride ratio, as Tammy suggested and
Raul mentioned, those contained welds. I mean, so there was a weld,
there was a heat-affected zone there, and they were covered. Some of the
crevice feet were on base metal, some were on weld metal, and some were,
you know, just across that. So, based on that set of tests, anyway,
there wasn\'t any high susceptibility of those welds.

Now, if you went through other types of thermal treatment or
heat-affected-zone-type treatment, you could affect this cutoff
temperature. I could imagine a critical temperature decreasing if you
increase the susceptibility of the material somehow. We\'ve not seen
that, but, you know, it could happen.

BULLEN: Bullen, Board.

That was actually the question I was trying to get at\--

PAYER: Okay, so then that\--yeah, that would\--and what that would do is
you would just track this further. You would stay on this same
trajectory. You would just go further.

BULLEN: Okay.

PAYER: Because it\'s defined. That cutoff point there is defined by 90
C.

BULLEN: Okay.

PAYER: So if you said 50 C, you\'d follow that trajectory out to here.

BULLEN: Okay. Bullen, Board.

Last question, and this was an obvious one that I have to ask. Is the
certainty of waste package performance greater or lesser if you
completely avoid Region IV? And I\'ll point to figure 75, which is your
last conclusion, which I really liked, which says \"never/anywhere\".

PAYER: Okay, repeat your statement again\--

BULLEN: Is\--is\--

PAYER: I want to make sure before I say yes or no, I want to make sure I
hear the wording because\--

BULLEN: Okay, I did not say uncertainty. I said is the certainty of
waste package performance greater or lesser if you avoid area\--or
Region IV?

PAYER: I think if you could completely\--I guess my quick answer to that
would be yes. It would be more certain, if you could avoid Area IV
because that\'s the only area that we see where the dripping can affect
the chemistry and so forth. You either have the thermal barrier and\--

BULLEN: Thank you.

PAYER: Fair enough.

LATANISION: Norm?

CHRISTENSEN: Joe, I want to go back to a point you made that I just
could maybe pick up on, and it\'s the question of what is a\--what is a
crevice? And, being completely outside this area, I guess the\--is the
issue that the EPRI folks brought up yesterday, that is the diffusion of
oxygen, for example, the limiting factor that determines a crevice? Is
that\--try to tie those two things together. Is that the issue? And then
maybe to ask your opinion of their approach to looking at, particularly,
the issue of oxygen diffusion rates.

PAYER: Answer the last part first. I\'m a real fan of that approach. I
think the whole area of corrosion science can benefit from more of that.
And in my mind, the Yucca Mountain Project could really take a
leadership role in the community of\--I think it\'s important to Yucca
Mountain. I think it\'s important to the whole community.

You could refer to this a bit. What sets up the localized corrosion is
this area within the crevice becomes active, and it stays passive out in
here. In a phenomena- logical standpoint, what happens inside that
crevice\--first of all, when you start off, the solution in the crevice
is exactly the same as out here, but inside\--and so you\'ve got little
local anodes and cathodes going on. You\'ve got some dissolution of the
passive film. You\'ve got some reduction of oxygen in the environment
that\'s going on. That\'s happening outside the crevice on the surface
and inside the crevice. As a feature of that, you use up the oxygen in
the crevice. It\'s consumed. And it can only be replenished then by a
transport process, diffusion into the crevice.

The other thing that happens in the crevice is you\'re putting metal
ions into solution, and you get to a point where the metal-ion
concentration will react with hydroxyl ions and precipitate hydroxides.
That drives the pH in the crevice down. You\'re taking hydroxyl ions
out. The acidity of the crevice becomes greater.

Also, while you\'re putting metal ions, cations, positive charged ions,
into this solution, you have to maintain electrical balance. So, some
negative charge, anions, have to come in there and chloride is one of
the most mobile of the anions. And so with time, you start off, the
crevice chemistry\'s the same as the bulk chemistry, but with time, the
oxygen goes down; the acidity increases; and the chloride level
increases; and all that drives you toward this critical corrosive
chemistry that you have to maintain.

Now, if this was permeable to oxygen or other species, then you have to
work that into the model to determine how that\'s going to affect this
critical crevice chemistry. That\'s the sort of 20,000 foot level.
David, do you want to add anything more to that from a\--

So, the geometry of this crevice affects the transport in and out of it.
There are electrochemical\--I mean, you can see there\'s a lot of
chemistry and metallurgy and electrochemistry that\'s going on in this
process.

SHOESMITH: David Shoesmith, University of Western Ontario.

No, Joe, that was very good. I just wanted to\--I had one point, which
is an unknown from the corrosion chemist point of view. The black area
that Joe shows is really the area that we\'re interested in. And what
you\'re really interested in is how vertically deep is it going to go,
whereas a lot of crevices like to go horizontally deep. Okay, so
horizontally deep then commonly leads to the increase in the currents,
and it\'s the metallurgical features of the material which stop it going
vertically deep. And we don\'t yet know what the relationship is for
Alloy 22, whether it\'s going to spread or penetrate.

The suspicion is because it\'s such a good material, it has to be
spreading. And I think Roger Staehle had some evidence to suggest it was
because he keeps going through this pit nucleation and inability to grow
process, which other people have seen. But that\'s still an unknown as
to how that\'s going to propagate.

LATANISION: Richard?

PARIZEK: Parizek, Board.

On Page 32, you\'re talking about dust, and then implied that there\'d
be only about a small amount of fixed dust once the doors were closed on
emplacement drifts. And dust would be related to construction in nearby
drifts that are going on, moving waste packages down, you know, into the
emplacement location. There\'s ventilation dust during the time when
things are operating there. Then there\'s drift degradation, debris
also, even though there\'s a stainless steel sheathing that\'s supposed
to be present as louvers. So, I can imagine, there\'s debris that can
still get in the waste packages. I think of the heater experiment where
you see rock debris on the floor and on the waste packages.

PAYER: Correct.

PARIZEK: And so the question about all of that is does the Department
plan to do something with this sort of debris as crevices to see if, in
fact, you know, dust maybe was a bad example, but rock debris maybe
that\'s not a good crevice compared to what you have in mind, but will
you do experiments with this to see if this is a non-problem?

PAYER: Let me cover that. Let me comment on the front part of it. The
important point, we think, is that when the drifts are sealed, you then
have no longer a source of ventilated or construction dust into the
packages. Whatever you have there is there. But that\'s a finite amount
then to determine mass balances and all those other things that can go
on. I\'m told by the rock mechanics folks, and Bo showed some
information on drift degradation, how much drift degradation is likely
to occur under different events, that a rock falling from the wall and
hitting the drip shield or hitting the floor is not going to create very
much small particulate. It might break in half and so forth.

The dust creating feature is during the actual fracture event when
you\'ve got these rocks slipping aside each other and you\'ve got a
corrosion guy explaining rock fracture to you here. So, you know,
but\--but the point is, you don\'t generate a lot of fine small particle
rock.

The other point of that is that Zell Peterman reminded us that the
composition of that rock drift-to-drift and zone-to-zone is very uniform
and it\'s not very corrosive. And so that\'s sort of good dust and\--if
you would. So, there\'s a finite amount of that.

Coming to your last question is will the Project and will DOE pursue
this issue of crevice formation by dust and rock and metal-on-metal?
Margaret Chu\'s corrosion advisor certainly will recommend that. And,
you know, no, it is in the plans. It\'s an important issue, we think,
you know, that is worthy of being addressed. We don\'t think it
necessarily has to be addressed prior to license application, but it\'s
one of these things that you would certainly like to know more about.

PARIZEK: Parizek, Board.

My good wife is here with me listening to all of this, and she remains
interested in this. Meanwhile, the house is idle and we\'ll get home and
it\'ll be dusty and she\'ll clean up the house again of this dust
that\'s been there since we left. And so the question is there\'s also
this air circulation within the drifts that stirs up dust, I guess,
that\'s in various locations that gets re-moved, I guess, re-transported
around. Is that part of the\--

PAYER: My sense of that is that those air circulation currents\--and,
again, I\'m slightly beyond my fringe of comfort here, so somebody can
jump in\--but the circulation currents we see, the natural convection
and the movement along the drifts, I don\'t believe are going to be
transporting very much dust. I don\'t see, you know, a little cyclone
wind tunnel in there type of a thing. Do you have high nitrate dust in
your house?

PARIZEK: I think we have\--

PAYER: If you do a lot of\--if you do a lot of, you know, wood
refinishing or something like that, you don\'t. You\'ve got problems.

PARIZEK: Well, that\'s\--I\'ll send some dust. You can test it. Parizek,
Board, again.

I guess your fault tree was independent of EPRI\'s because your yeses
were good, and their nos were good. And that\'s opposite so\--

PAYER: Yeah, we have to decide on which is yes, good or bad.

PARIZEK: There was also\--I liked your analog or analogy with the coins.
It gives a real good sense of how thick something is and rates at which
things happen. So, in terms of understanding from the public, it\'s a
useful idea. And I would be most interested in knowing what DOE\'s
confirmation testing plan might include based on today\'s general, you
know, all the presentations that everybody\'s given. There must be lots
of bits and pieces of work that needs to be done to add further
understanding or confirm the works that\'s been done to date and
be\--I\'m sure the Board\'s going to be anxious to learn more about
these details as we go along.

PAYER: And then perhaps Bob can comment on that in the wrap-up period.

PARIZEK: Yeah, and\--

PAYER: Or somebody. Not me.

PARIZEK: And, Parizek, Board.

One more point. There seems like when you start a crevice, I got the
feeling that once you\'ve got one, they sort of self-propagate
themselves. They sort of\--they eat their way\--

PAYER: Well, they can\--

PARIZEK: And the question is, at the different time periods when\--at
750 years to 1375 years when you really can\'t have anything bad
happening, the point is if you start a crevice and it didn\'t finish,
can it pick up and take off at a later date? So that there are these
periods you think you\'re home free, but maybe the damn crevice sort of
kicks in again for reasons you didn\'t expect and it\--

PAYER: It could persist beyond that to some extent, but not forever. And
there are also\--there are a lot of processes. The other point that
hasn\'t really been developed and elaborated on here is when we do the
crevice corrosion tests in a laboratory and we\'re doing them in
immersed environments and you\'ve got a large amount of electrolyte out
here. And when we do the accelerated tests in the environment, we do it
with a potentiostat. So all of the dissolution current in here, all of
the anodic current from the metal dissolution has to be balanced by
cathodic current out here. And when we run that test in the laboratory,
we supply as much of that as necessary to keep the crevice running.

There are significant cases where the amount of cathodic reaction out
here causes stifling of the corrosion rate. You can only\--and now
we\'re talking about thin layers of dust or deposits on metal surfaces,
that in a very qualitative sense, I cannot imagine, would be a very
effective cathodic surface to support, you know, localized corrosion
over a long rate. That factor and factors like that have really not been
taken into account and backed up then with some experiments and solid
models.

PARIZEK: Parizek, Board.

Just one more point about the idea of the confirmation testing programs.
The things that are still not yet known or well-known, and that was the
role, for instance, of the nitrates and how does that actually cause
protection? I mean, it seems like if it causes protection, that\'s good
enough for government work. On the other hand, maybe why it does is, you
know, part of a fundamental understanding that a program would be
striving for.

PAYER: Sure.

PARIZEK: And the whole idea of passive films is to how long are they
likely to be around? You\'re talking about a passive film you\'d like to
have going into the 10,000 year time frame. And so there may be
mechanisms that help break it down for reasons that nobody understands
for the same reason that nitrate is good. You know, the idea is the
fundamentals here. So we\'re really interested in where to go with some
of these fundamental\--

PAYER: Well, I\'m\--

PARIZEK: \--studies. And I would hope it\'s in the confirmation or the
research and science and engineering or something here\--

PAYER: There\'s two arenas in which we can imagine making progress in
that area. One is some of the activities in performance confirmation.
But I think the things you\'re touching on now fit much more in what
we\'re defining as Margaret\'s science and technology program. And
that\'s very much where a lot of that work will be focused is a more
fundamental understanding of these types of electrochemical processes
and transport processes. That, to my mind, is a clear definition of
things that fit in science and technology. I would suggest getting a lot
of universities working very hard on this. And a couple national labs,
maybe.

PARIZEK: And, Parizek.

One more point. I feel better today than I did yesterday. Yesterday I
thought maybe I felt like posing some of the early questions was dumb.
But in the long run, this whole process has resulted in a clearer
understanding, a lot of detail, a lot of effort on the part of a lot of
people. And it seems to me it\'s adding a lot of credibility to the
program on how metals are likely to behave. So, I appreciate the\--

PAYER: Well, we\'re approaching beer time, and let me\--let me
compliment and, you know, the Board for your report. I mean, it caused a
lot of excitement, let me tell you that. It got the e-mails lining up
and a lot of conversations. But I know having talked to some of you
on-line and off-line that one of your greatest intents was to try to
stimulate and catalyze addressing some of these issues. And, Ron,
you\'re exactly right. A lot of putting this whole thing together,
there\'s\--progress has been made of understanding the processes. We\'re
quite pleased with the way it\'s come together and where the story is
now, to be quite honest. I mean, that\'s why we can stand up here and
make these kinds of conclusions. But you were catalyst in doing that.
And, you know, so we thank you from that standpoint.

LATANISION: As Chair of the session, however, Richard, I just want to
say we\'re nowhere close to beer time yet.

PAYER: That\'s right.

LATANISION: We\'ve got a lot to go. Dave, you have a question. And then
I want to make sure that we do\--

DUQUETTE: Thure does, too.

LATANISION: And Thure. And then I want to make sure we leave a moment or
a few minutes for the audience. So, let\'s start with Dave.

DUQUETTE: Duquette, Board.

It\'s just a point of clarification. Slide #58, please. That\'s the data
that shows the chloride concentration and so on and so forth.

PAYER: Correct.

DUQUETTE: What environment were the DOE tests run in? Is\--I mean, we
know that the CWNRA did those in magnesium chloride, I believe.

PAYER: Yes.

DUQUETTE: And what was the environment that was used for these tests as
part of\--

PAYER: Tammy, Raul, do we\--

DUQUETTE: \--by the Department?

REBAK: This is Rebak, at Livermore.

Both the Center and our data is for sodium chloride solutions.

DUQUETTE: For sodium chloride?

REBAK: Yes, pure sodium chloride.

PAYER: Straight sodium chloride of this molality. And the temperatures,
this is the Ecrit 95 for the Center, and 90 for the, I guess, the\--for
the Livermore data, is that\--

REBAK: Yes. All Livermore data, 90 degrees C.

DUQUETTE: Okay, thank you. It was just a point of clarification.

LATANISION: Thure?

CERLING: Cerling, Board.

I\'m glad that 43 is still up because one of the things that it chose is
a difference in chemistry, as you pointed out, between the bulk solution
and the solution in the crevice. And so what my question has to do with,
what happens to the chloride-to-nitrate ratio in the crevice as it
propagates and how does that compare to the bulk solution composition?

PAYER: The chloride-to-nitrate ratio\--or the nitrate-to-chloride,
whichever side you want to do that, but more nitrate is good\--helps to
define the conditions in which you\'ll initiate this crevice corrosion.
I don\'t know that we have information on the effect of nitrate chloride
once you initiate it in the propagation mode. Do any of you folks know
of any data specific or general in this?

REBAK: This is Rebak, Livermore.

Also, we didn\'t do any data, but there is some Center data that I
presented a couple of years ago at the MRS meeting in Boston and where
they showed that sometimes they initiate the crevice, and then they add
the nitrate, and nitrate actually suppresses the growth of the crevice.
That\'s been reported before.

SHOESMITH: Yeah, Dave Shoesmith, University of Western Ontario.

Just to back that up, although the observations on Alloy 22 might be
sparse, there are observations on other materials, oxi-anions when they
get inside the crevice can stifle it.

CERLING: But they have to somehow get inside the crevice?

SHOESMITH: Yeah, if you were to look at the transport number for
chloride and nitrate, they\'re not that much different. Chloride as
preferential, but only to a small degree. So, if this is an ionic
migration process into the crevice, there\'s no reason why you should
discriminate in a major sense between chloride and nitrate. It will, but
not to a major sense.

CERLING: And then just a question as very much a non-corrosion kind of
person, you made the comment about the critical temperature being 90
degrees or whatever the temperature is. And so my question is if a
crevice has already been initiated and it goes through that temperature,
will it continue to propagate or does that basically kill the crevice
growth?

PAYER: People do experiments where they intentionally start a crevice,
as we did there, and then lower the temperature and see where it will
arrest. So, there is an arrest point. I\'m not sure exactly where it is
for these sets of conditions we put here.

CERLING: Thank you.

LATANISION: Let me ask whether there are any questions. Roger Staehle?

STAEHLE: I have a few comments. You can turn off the slides. I think
we\'ve all had enough slides. I thought I\'d talk with just plain words
and say a few things.

Historically, the process of prediction is basically based on several
important ideas. One is defining the local environments. Until you
define the environment, you can\'t define the corrosion process. The
second is that you need to define the material. What is the structure
and properties of the material? And third is you need to define the
modes of corrosion and the dependencies of the modes on temperature and
stress and so on.

So, in 2001, there was a very nice meeting at the Case Western Reserve
that I think Joe hosted and brought together many of the actors in this
program. And I pointed out several things there at that time that, first
of all, there had been to date no accelerated tests. By 2001, there were
no serious, if any, accelerated tests on the materials of construction
to the question of the heated surface. And third, there were no serious
surface definitions of what\'s on the surface. And so I was concerned
that without those kinds of acknowledgements that you couldn\'t get very
far.

And so the Nevada Program that was set up started to answer some of
these questions, and not to say that Livermore didn\'t also start to
work on them, too, but Nevada Program developed an accelerated testing
program. They developed a program to look at surface environments. And
they developed a program to define the mode of corrosion of C-22. And,
so far, we\'ve made a lot of progress. I won\'t say that we\'re doing
all the things we know how to do, but we are doing some things.

For example, we have developed an accelerated test approach. Not
everybody, of course, agrees with it, although it\'s not too different
from what Livermore seems to develop. We\'ve developed a method for
analyzing surface chemistries. We have started to define the rates of
corrosion as a function of primary variables. And, again, there\'s a lot
more we know how to do that we haven\'t done. And so, having identified
those major issues and prediction, the Nevada Program has set about to
answer some of those questions.

Now, it seems to me that the questions that have to be answered, that is
the engineering problem, essentially are the fact that we have a waste
package; it\'s in a rock full of chemicals, and rocks full of chemicals;
it\'s got a heated surface; it has an oxygen environment; and it\'s got
water. And those are the main components of this enclave that we have to
deal with. And the issues here have to do with how this is all
distributed, but that\'s the system that we\'re working in. We have to
acknowledge that system.

Now, one of the things we know right now next is that C-22 can
perforate. It is not always passive. And it can perforate very, very
rapidly in environments that can be reasonably argued to be relevant
depending on how you define the surface. Third is that there are
multiple paths. There is not one path to an answer here. There are
multiple paths. And I don\'t see the acknowledgement that we\'re
dealing, not with a single path, with multiple paths.

Next, we\'re dealing with a matter of complexity. This is not a simple
set of four domains. It\'s not a simple set of a passive metal, but
it\'s a complex system. And complex systems need sets of approaches, not
single approaches. And I\'m concerned that I don\'t see that kind of an
idea. Complex systems need bounding approaches, not just one approach,
but boundaries. And I don\'t see an effort to define those kinds of
boundaries with respect to corrosion.

And, finally, in the engineering situation, there\'s no inspection. In a
nuclear plant, you would inspect the nuclear plant once every two years,
and you kind of know what\'s going on. But here, you don\'t inspect the
once every 2 years or 10 years or 100 years or 10,000 years. You just
don\'t inspect it. So, whatever you do in the beginning is what you\'re
going to have to live with, which is a totally different engineering
problem than anything I think we\'ve dealt with in the past.

Now, I have some very specific comments on much of what\'s been said. I
have a set of comments and objections to what has been said by many of
the speakers that I won\'t bore you all with, but I don\'t find as much
satisfaction in what\'s been presented as some of you do, and maybe you
don\'t either. But, for example, I\'m concerned about the idea that the
passive film is pervasive. It\'s not pervasive. The passive film is a
special case and a 10 to the minus 7, 10 to the minus 8, and per square
centimeter, is not the general case.

I\'m concerned about the concept of nitrates and sulfates and carbonate
inhibitors. Those terms of inhibition are just wrong. They are specific
for certain cases, but not for all cases. And in this case, I don\'t
think they\'re all that applicable in the first place.

Now, I don\'t think we can also make progress by calling this a
corrosion resistant alloy. It\'s an alloy. It\'s got certain properties
and certain environments. But to call it a corrosion resistant alloy, I
just think is a big mistake. I think as an alloy that will work under
some circumstances, and only those circumstances. I think this concept
of realism and what\--let\'s do something realistic, I think we have to
reexamine the concept of realism. And realism is what to somebody fits
his predisposition, but not necessarily realism. So, we have a set of
realisms here, not all of which are congruent. And I hear a lot of the
terms like \"I believe\" and \"I argue\", but I don\'t hear so much
facts, but I hear a lot of, it sounds like, a religious revival
actually.

Now, I think the way we\'re going to make progress here is by making a
serious effort to define the surface composition. The most important
idea here in prediction is to define what is on the surface over time.
And I think to say we define what\'s on the surface over time is not a
single answer. It\'s a set of answers. We need five different
environments or ten environments or three environments, but it\'s not a
single environment. We need a set of credible environments that we can
identify that we need to investigate. And I\'d like to see someone lay
out that set rather than saying, \"well, this is the answer,\" or \"this
is the environment.\" I\'d like to see a set of environments. I think
we\'re\--well we\'ve made progress, but\--and then I\'d like to see us
define the modes of corrosion of C-22.

The idea that C-22 is totally a passive material all the time is just
ridiculous. There are many ways that C-22 can corrode. We need to
develop the dependency of the corrosion of C-22 on primary variables
that cover this range including ferric ions, incidently.

I would like to see us accept the idea of complexity. I think this whole
thing has gotten into a sort of a quantitative mantra here that is
entirely inappropriate for the complexity of the system. And I\'d like
to see us, in a sense, quantify the concept of complexity. I would like
to see us develop an approach of bounding situations rather than getting
precise situations. And these complex systems, you cannot deal by having
a central value. You\'ve got to have a bounding approach.

Now, I\'m a little bit concerned also about some of the language I hear
here. First thing I ever did in serious corrosion engineering was look
at the cracking in Dresden reactor pipes in 1967, and I observed stress
corrosion cracking at room temperature in stainless steel. And the gray
heads at the time said, \"Roger, don\'t worry about it because it\'s a
bad heat.\" Well, the next time it failed was still a bad heat. But
after awhile, they\--on the way to failing all the major piping and
DWRs. And I hear some of that same pattern here that, \"well, you just
had one set of a certain kind of corrosion here, but it won\'t happen.
It\'s not general.\" Well, I\'ve heard that before. I know what that
sounds like. And I think we have to be careful we don\'t get ourselves
trapped in catch phrases and in slogans.

And, finally, after we\'ve made the arguments I made yesterday in a half
an hour that probably should of been a couple hours, somebody told me,
well, the reason I\'m making those is because I was being paid. Well,
you know, a fox smells his own hole first. And I\'m concerned about the
intensity of the feeling here about what\'s going on rather than the
objectivity. And I think that we need to think seriously about the
objective approach to developing sets of ideas, bounding conditions, and
recognizing complexities.

LATANISION: Thank you. If there are no other comments, I guess there
are. Okay, let\'s take them.

McCARTIN: Tim McCartin, NRC.

I would like to respond in part to the comment about inspection and it
was mentioned earlier today. But the regulation does require a
performance confirmation period. We would expect that would be at least
50 years. The regulation does specifically require performance
confirmation for the waste package. Although there\'s not an inspection
for 10,000 years, I think people would laugh at us if the NRC had a
requirement to inspect for 10,000 years. There is a performance
confirmation program that is a, I would say, a corollary to the
inspection program for an operating nuclear facility. And that, you
know, we look on that as 50 years of testing and challenging the
assumptions on the waste package.

Thank you.

LATANISION: Yes. Okay.

AHN: Tae Ahn, NRC.

A couple of clarification questions to Joe. In your Slide 67, has\--

LATANISION: Pull the microphone down towards you.

AHN: Slide 46, there is a diagram\--no, his case, 67. Yeah, the right
side curve there is a diagram showing inaccessible region. He defined
during his talk, but I still do not understand what the definition of
inaccessible region. That\'s one question.

The other question is, Joe, in your Slide 13, it\'s basically TGA
testing. Could you tell us some idea about the air flow rate you used in
the TGA testings?

PAYER: Okay, let me\--let me ask Greg to double up on both of those. One
was the definition of the inaccessible region. Why is it inaccessible?
And then the second one is flow rates in the TGA experiments.

GDOWSKI: Hi, Greg Gdowski, Lawrence Livermore National Lab.

I\'ll do the TGA one first. The air flow rates were such that we could
exchange the complete volume of the system within one minute. So, I
think the volume of\--I can\'t actually remember what the volume of the
cell is, but the air flow rate was such that it would be completely
exchanged within a minute.

By the inaccessible region, that\'s where the water vapor pressure would
have to exceed one atmosphere in order for you to obtain those relative
humidities in that region.

PAYER: So water would boil off at that. You couldn\'t maintain an
aqueous environment in an ambient atmosphere under those conditions.

GDOWSKI: The repository, you\'re above the local ambient pressure there,
so you can\'t. The water pressure cannot exceed that.

LATANISION: All right. Thank you.

I am going to ask Bob to make some comments, but I\'m going to\--as
indicated on the schedule, but I\'m going to delay that until we take a
break. And I\--you hear a sense of relief here on the sideline. But I
want to make clear a couple of comments before I do that.

Number one, I\'m very sensitive to the fact that yesterday we apparently
lost someone who wanted to speak during our public comment period. And
we\'re on the schedule to have public comments at 5:20 and we\'re going
to do that so that no one will be out of sync.

Secondly, I do want to give you an extended break because the idea is
for each of the constituencies who are represented in our deliberations,
and by that I mean not just the Project, but also the State of Nevada,
the NRC, Catholic University\--well, that\'s the State of Nevada, right?
And EPRI, of course. Sorry. Thank you, Mark. I want to give you all a
chance to collect your thoughts and to\--and perhaps in Roger\'s
statement he\'s responded to this already, but I want to give each of
those constituencies an opportunity when we come back to provide some
wrap-up comments.

UNIDENTIFIED SPEAKER: Mr. Chairman?

LATANISION: Yes?

UNIDENTIFIED SPEAKER: About five minutes?

LATANISION: About five minutes each, exactly right. No more than five
minutes. But I do want to make sure we have an opportunity to hear from
everyone in a summary sense. And, Bob, you will lead off given that
we\'re deferring your point in the program right now. So, let\'s now
take a break. It\'s 5:00 o\'clock. We must be back in the room at 5:20,
and the first item on business will be public comments.

(Whereupon, a brief recess was taken.)

LATANISION: Let\'s come to order.

We have three people who have signed up on the public comment register.
And so I will invite Judy Treichel to come to the podium?

TREICHEL: Judy Treichel, Nevada Nuclear Waste Task Force.

Thank you very much. After all these many, many years, the Technical
Review Board is still the only entity that provides this sort of
opportunity for public interest groups or for people who don\'t have any
professional part of the program, particularly not financially. And so
as a person who works for an outfit that operates on 120-thousandths of
the DOE budget, I totally appreciate this opportunity.

The first thing I would like to say is that there has been reference
made to the drift-scale test in a lot of the presentations that were
given. And the drift-scale test is just sitting out there. It\'s about
six and a half years old, as far as operation goes. It heated up for
four years. It\'s been cooling down for about two and a half. I get the
weekly temperature readings off of the thing, and the temperature\'s not
dropping very fast anymore. It\'s down below boiling, but it\'s still
pretty warm if you were going to just walk in. And it appears from those
sheets that come every week that nobody has walked in.

So, it would seem to me to make sense that the Department of Energy
should consult with the State, certainly, and I don\'t know who else,
but before the door opens, it would seem like there should maybe be a
plan because this may be the only way or the only opportunity that there
is to collect stuff like dust that accumulated and actually got heated
up for a period of time. And there\'s been criticisms of the drift-scale
tests.

I\'ve been out to the site countless times and with a wide variety of
groups. And when people are real dazzled, they believe that this is a
replica of an operating repository. And when they\'re not so dazzled,
it\'s just sort of something that\'s there to prove the model. But it\'s
only in one spot, and the spot may not be like any or all of the
repository, and so you\'d only have one kind of dust, and it might not
be worth anything, but I really don\'t think you should miss the chance.

And the statement was made that there was no seepage or there was no
water moving because of that test, and that\'s not true either because
I\'ve been out there and felt the rain that was created there. And there
finally was a poster that was called, \"Why is Water Dripping on my
Head?\" So, there definitely was something moving around and it was wet.

In January of 1997, I was asked by the Board to give a presentation, and
the thing was called, \"The Total System Performance Assessment and
Transparency. How can the public know what the TSPA is and what it
means?\" And I guess that was the first meeting that Dan and Norm were
at, so I\'m sure you remember every word of this, but I thought it was
interesting and I want to disagree with Margaret about the value of
TSPA.

At the time that I gave this presentation and the reason it was asked
was that there was a war going on because the Department of Energy had
suggested that they change the guidelines. And the major change at that
time was to take out the disqualifying and qualifying conditions. Those
were things that the public really understood. We knew what those were
and we could recite them and we knew that those had to be met. It was
going to be replaced with something called a \"Total System Performance
Assessment,\" that seemed real mushy, and in some ways it still does.
And one of the\--I\'m certainly not going to read this, but there\'s a
couple of things that seem pretty interesting after over seven years.

The public was led to believe both in face-to-face meetings with the
Project and through many media reports that Yucca Mountain could and
would be disqualified as a repository site if any one of the qualifying
conditions could not be met. Never was it mentioned during that time of
frequently held public meetings and updates that disqualifiers could be
fixed or mitigated or averaged against other factors.

For it to be of any value\--this is TSPA\--it must be used to understand
what is not known rather than as a basis for confidence in predictions
of repository performance. The TSPA has to be a tool and not a product.
And at that time we worried a lot that uncertainties could be disguised
as manageable weaknesses resulting in layers of assumptions that
ultimately create an illusion of confidence and accuracy. And one of the
very last sentences is that, \"At this period of time in January of
1997, a major remaining unknown due to lack of data is, what will be an
acceptable thermal load?\" And here we are all this time later and
we\'re still arguing about the thermal load.

But there was a lot of problem with TSPA, and it\'s still being argued
back and forth. And as a spokesperson for the public, we all know that
when something goes wrong, it\'s not the total system that fails. It\'s
one specific thing or, as DOE would call it, \"an initiating event\".
And at TMI and at Chernobyl and at the Challenger, and at any of the
disasters we can think of, there was just an initiating event. It
wasn\'t the failure of the whole system. So, I think that should be kept
in mind.

In also looking at this, I think it\'s interesting that the problem that
I pointed out in that presentation about the thermal load has been taken
as a lemon and made into lemonade by the Department because as of today
there\'s now a thermal barrier instead of problems about whether or not
you can have a hot repository. I also think that the showing of the
C-22, or Alloy 22, as a product in industry is a little strange because
I wouldn\'t think that any of the companies that were using that
material that Joe Payer showed in those pictures would be thinking of
using it for 10,000 years and probably would figure that it would have
to be replaced at some time. And if it lasted for even 100 years, people
would be very surprised that it had. So, with anything we\'re familiar
with, there\'s always a disconnect when you\'re talking about a
repository because it\'s not like anything else at all.

And, finally, I find it very troubling that the Department has taken
what they call a \"Prevention Plan,\" and any time there\'s something
that\'s a problem, it never really becomes\--it certainly doesn\'t
become a showstopper or a disqualifier, but it never even becomes a
serious hurdle. It always just has to be put in the category of things
that can\'t happen. So, if there\'s problems with the saturated zone or
unsaturated zone, then you get this can that can\'t fail for 10,000,
11,0000, 40,000, however many years. And then those things don\'t
matter.

And if there\'s something wrong with something inside the surface
facility, if there\'s a possibility that something could go wrong
because something got dropped, then you make it impossible for it to
drop. And in some ways that\'s very good. But in other ways, it masks
the possibility that something is going to go wrong and that a human
factor or any kind of thing that can possibly go wrong will, and it had
been ruled out.

So, thank you for the opportunity. I have this letter if you want
another copy or if your filing system is great, you may still have it.

LATANISION: Thank you, Judy.

Let me next call on Mike Lee. According to his affiliation, Mike is with
the ACNW of the National Research Council. Is he in the audience? Yes,
sorry. There is another NRC, of course. But I guess Mike has left. All
right.

How about Rod McCullen?

MCCULLEN: Thank you. Rod McCullen, Nuclear Energy Institute.

Yesterday, out on the table I picked up this brochure. I think it\'s the
first time I\'ve seen this on what the Nuclear Waste Technical Review
Board is all about, and it\'s a pretty good brochure. And I noticed in
here there\'s a bullet list of three things the Board does in conducting
its ongoing review. The Board does the following. The second bullet says
takes a \"systems\" view of repository performance in waste management.

And I was really struggling yesterday with the contrast between this
statement and the mission of the Board, and the statement that was
asserted in a letter and emphasized in the Board\'s presentations
yesterday telling DOE, \"don\'t use Total Systems Performance Assessment
to dismiss our concerns.\" And, fortunately, I think over the last two
days looking at everything that\'s happened in totality, I started to
see how that\--how that dilemma gets answered. And I want to try to wrap
some of that up because I think it\'s instructive.

Most particularly important was the presentation by Dr. Chu this morning
and some of the discussion that ensued afterwards. First, it was healthy
to hear that the Board doesn\'t, in fact, completely disbelieve in TSPA.
I think that was good. Also, I think that for Dr. Chu to explain the
fundamentals of the approach that we use, the risk informed approach
that\'s prescribed by regulation and resulted from the recommendations
of a lot of science over a lot of years, particularly one fundamental
that ties in very well with, I think, everything we heard today is this
notion of a risk triplet. The idea of you ask the question what can go
wrong, how likely is it, and what are the consequences?

And the thing I\'ve seen in the Board\'s letter, and the Board\'s
report, and the Board\'s presentation, and the information by the State
of Nevada, and, until today, the stuff that DOE was responding with,
addressed only the first element of that risk triplet. That is, that
question of what can go wrong? I think Dr. Latanision asked Dr. Chu the
question of, \"well, if I\'m an engineer, I want to avoid things.\" And
I am an engineer, and I think when you come to avoiding things, you have
to look at all three elements of that risk triplet.

And I think that what we\'ve seen in these last couple days,
particularly with the decision tree analysis by EPRI and by DOE, and
it\'s interesting that they both independently came to very similar
conclusions, explains a systems perspective addressing all elements of
that. What can happen? At each step of the tree, what can happen? How
likely is it? What are the consequences? What can happen next? How
likely is that? For the first time, and I agree with Judy and I think
this was clear in Dr. Chu\'s talk, TSPA is just a tool. But for the
first time, I think today we saw an explanation of that that is a lot
less of a black box in terms of that decision tree analysis today and
yesterday.

There\'s also a second element to taking a system\'s approach to
evaluating repository safety that I think is important, and it keeps
coming out every time Dan Bullen gets to ask questions. And that is the
notion that he\'s asked the same question over and over again, the
question of why not just stay in Environment IV, why not just stay in
the cold environment? And the answer to that is actually very simple.
It\'s really not an answer you can give just in the context of a
corrosion meeting though because it touches on something broader. And
the answer is you don\'t design a repository based on a single input
parameter.

In fact, what you do is you design a repository, and I think what DOE is
showing that they\'ve done very well, design a repository that can
mitigate all those things that are most risk significant. You don\'t
look at a single parameter without respect to its risk significance. And
I think what we\'ve heard in these presentations is this notion of
localized corrosion simply isn\'t very risk significant.

So, there\'s this need to look at all the elements of risk over all the
elements of the repository, and come out with an integrated solution. I
think DOE\'s ability to do this has been dramatically bolstered by the
Board asking these tough questions. I think this is a particularly
compelling example of the value of this type of critical review, that
because for the first time today we are, and yesterday, are seeing
really a very solid explanation of this. I think in the case of
localized corrosion, I think the Board\'s questions have been answered.
I think they\'ve been answered thoroughly, completely, authoritatively,
and definitively.

I just hope, you know, of course, the Board needs to come to its own
conclusions as to whether or not they agree with that statement, but I
would just hope that in addressing that, that you remain true to your
own advertising.

Thank you.

LATANISION: The conscience of the meeting. Thank you. Thank you very
much.

Last call for Mike Lee. I take it that Mike is not in the audience, and
so we will now go to the wrap-up statement segment of the program. And,
Bob, I will ask you to go first.

ANDREWS: Thank you.

It\'s a pleasure to be back this afternoon. And my objective in the next
15, 20 minutes is to summarize what you\'ve heard from the Department,
from Bo, from Carl, from Joe, and the relevance of that information to
addressing the Board\'s questions that were, you know, appropriately
raised in the October and November letters and reports, respectively.
And to end that way, summarize the conclusions not only with respect to
the Board\'s questions, but with respect to the broader question of the
range of environments, thermal, hydrologic, chemical environments, on
the package and the range of degradation modes of the waste package in
those environments. You can go on to the next slide, John.

As I said this morning, our goal was to answer the questions the Board
raised in that letter and to be forthright with our\--the response with
new information, to point out where that new information directly
addressed the Board\'s questions. I think they were appropriate
questions. They were based on the information available last May. I
think as I said this morning, the analyses and model reports upon which
this information resides last May were not even in draft form. I don\'t
want to say the information was baking, but how you integrate the
information to answer questions that are relevant to the behavior of the
package, in particular, in the environments, both thermal and chemical
environments that are likely, was probably not fully developed last May.
Therefore, the Board\'s questions, which I think were appropriate
questions.

A lot more has been done. I think you appreciate the additional work
done not only by Joe and Carl and Bo to synthesize it and present it to
you, but the researchers and analysts at the labs, the survey within BSC
that provided the fundamental information that allowed Bo and Carl and
Joe to present that information to you. And it was under Margaret\'s
direction and forceful leadership that got us, you know, to integrate
appropriately. And there were the additional information explicitly
developed to explicitly answer some of the questions that the Board
raised, and I think you saw some of that, in particular, in Joe\'s talk.
So, if I can go onto the next slide, John, I think Slide 4.

So we focused on the data. We focused on the models. We focused on a
range of lines of evidence, multiple lines of evidence, not just using
our data, but using data available from others; data available from NRC,
data available from the literature, analog information to tell a story,
if you will, of all aspects, not just, you know, a particular test to
answer a particular question and to use those data and multiple lines of
evidence to define the range of environments both during the thermal
period and after the thermal period.

You know, we purposely broke Carl\'s talks, as we said this morning,
into two parts because the Board\'s questions really were in two parts.
And I think the chemical environments are in two parts. One part is the
salts in the dust and how they deliquesced. Another part is the liquid
water and how it evolves when it can contact the drip shield and the
waste package. So, it was two separate and distinct discussions.

We discussed a little bit, not at full length today, the uncertainty in
some of the models and analyses and data that are used and how we\'re
propagating that uncertainty. I believe we have an opportunity to
discuss that with the Board in much greater detail from the full
system\'s conflict component, not just the in-drift environment and
corrosion aspects as presented today.

It\'s important to point out that that system\'s representation will
include that uncertainty, does include that uncertainty and variability,
and it also includes the low-probability events and features, which were
not the focus of today. We tried to focus on the Board\'s questions
which are kind of likely behavior, likely thermal hydrologic response,
likely chemical behavior, and likely degradation characteristics of
Alloy 22. All of those effects, though, and uncertainty have to be
incorporated in the TSPA for the evaluation of the site per Part 63
requirements.

We purposely did not show you any TSPA results. We did not want to
dilute the discussion away from the critical nature of the Board\'s
questions, which were really after the fundamental technical bases
underlying the models, underlying the analyses, and underlying the
response of the thermal hydrologic system. And we did not want to, if
you will, dilute that with a discussion of does it make a difference
from a TSPA perspective? But you saw some other people put it into a
TSPA perspective. Both EPRI and NRC presented results of, well, what if
we\'re wrong and what are the implications from their models using their
analyses, even though they are only insight-producing models for either
of those two institutions, to give you a sense of does it make a
difference from a TSPA perspective?

Let me go on to the next slide. And I probably can\--well, let me stay
on this for a little bit. This walks through the individual processes,
more or less, as we presented them. And they\'re all processes that can
affect the environments, and all those environments can affect the
degradation characteristics of Alloy 22 in the repository. We talked a
little bit about drift degradation and, if you will, nominal
performance. We did not talk, although Bo had in a backup slide, drift
degradation in a destructive event, in a low-probability seismic event.

We did focus a significant amount of attention on the thermal hydrologic
processes because, as you saw from Carl\'s briefings, understanding that
temperature/RH representative profile and the distribution of possible
temperature and RH profiles does affect the type of chemistry that can
evolve whether it be an aqueous chemistry or whether it be a dust
chemistry. So, it\'s important to have a fundamental understanding of
the temperature/humidity response and the range of temperature/humidity
responses. It is different in different places in the repository. It is
different for different rock types. And it is different for different
waste package types. And so that range of thermal hydrologic responses
are important to consider.

Clearly, that thermal hydrologic response is a function of the design. I
think we all acknowledge that how you load the repository, how you
ventilate, how long you ventilate, what maximum load, heat load, you put
into a particular waste package, how closely you space the packages, all
of those variables do affect thermal hydrologic response. Even given
those variables, even fixing those variables, which of course the
current design has done as presented to the Board in January, gives us a
wide range of thermal hydrologic responses that we\'ve presented to you.
We showed three representative ones, but then we showed the, if you
will, the gray area where all of the other thermal hydrological
responses are.

Changing one of those design parameters, if you will, would clearly
change the number of packages that would see a particular type of
thermal hydrological response. Some might be cooler. Some might be
warmer. Today some members of the Board recommended going hotter. I
guess it was individual opinions as expressed by the Board. And I think
that Dr. Duquette said, individual opinions are allowed by Board members
and it\'s only the formal positions that count. But I thought that was
kind of an interesting view of some of the Board members. And as pointed
out, Dr. Bullen asked his favorite question of what about colder? So,
there\'s a range of possibilities, but there\'s a range of responses
that are being projected in the thermal hydrologic analyses.

The deliquescence of salt and thermal seepage affect both parts of the
initiation of localized corrosion depending on whether you have liquid
water present or not. Next slide, John.

I think we talked about aqueous solution chemistry. And then to,
finally, the last bullets there that Joe talked about with respect to
the initiation of localized corrosion and the general corrosion rate
with the passive layer or without a passive layer and the effects of
crevice corrosion were all discussed at great length with the additional
data that we have under a range of environments, repository relevant
environments, to address those. So, in the next few slides, what I\'m
going to do is just kind of summarize the conclusions that Bo reached,
that Carl reached, and that Joe reached. I have generally a
representative slide over to the left to talk about what the subject
matter is and what Bo talked about, but I want to focus on the bullets
that are on the right.

I have to admit to, I took the liberty to a three-points insert slides
that were presented yesterday; one from EPRI and two from NRC, one from
Roberto Pabalan, and one from Darrell Dunn because of the relevance of
their conclusions to the same issue we were talking about today. So when
we get to those, I\'ll just reinsert those three slides from those
presenters from yesterday.

Okay. With respect to the thermal hydrological response\--and I\'m not
going to go point by point with respect to the Board said and we said. I
just want to say these are what we presented to you. First off, that,
yes, the thermal conductivity is important. Uncertainty in the thermal
conductivity is important. And a range of thermal conductivities for the
lower lith and middle non- and for the upper lith and lower non-, I
guess, were incorporated into thermal hydrological responses. They were
incorporated in the seepage models, incorporated in the thermal
hydrology models.

So, there\'s a wide range of thermal conductivities that have been
evaluated and they\'ve been developed based on the in-situ tests that we
performed, and include the effects of variable lithophysic porosity and
various scale-type effects in developing a reasonable thermal
conductivity for the basis of the models. All of the models with thermal
hydrology, the thermal seepage models, particularly the seepage part of
the thermal, were based on in-situ direct observations. I think Bo went
through great detail of almost test-by-test. There\'s other tests that
are the bases, but I think he presented the representative tests for the
bases for those models.

The calculations that we have of temperature and humidity\--let me
switch to the second on the screen, the other screen, John\--is a wide
range. That gray band that you see is the full range from low thermal
conductivity, low percolation rate, if you will, to high thermal
conductivity, high percolation rate, giving the maximum temperature,
minimum temperatures, respectively, and everything in between. So,
nominal percolation rates and high, medium, and low thermal
conductivity. And there\'s a range of percolation rates across the
repository block that are factored into the thermal hydrologic
responses. Not one five millimeter per year percolation rate, but that
percolation rate, in fact, very spatially across the repository block.
And that\'s factored into that full distribution, as well.

So, we have a family of thermal hydrologic responses. And if you like
plotting them as a function of time, then you can plot them as a
function of time, if you like, and it\'s more representative to plotting
them as TRH curves that vary with time. Then we showed them both ways,
essentially. It actually becomes more relevant from a chemistry
perspective to plot them as we did on the right-hand side rather than to
look at them as a function of time, but understand that that
temperature/humidity duplet is really changing with time for each
package. For each package, some are a little cooler and some of them are
a little warmer. And we believe that that reasonable range as
encompassed in the left-hand slide there has been incorporated in our
projections of the response that are then fed into the projection of how
the rest of the repository system responds.

So, I go on to the next slide with respect to seepage and thermal
seepage. Probability of seepage during the thermal period is low, but
not zero. You\'ll see even on the right-hand slide there\--or, I\'m
sorry, the left-hand slide, but the right-hand picture of the left-hand
slide, even at a few 100 years, there\'s a possibility for some seepage
to occur over some packages because the temperatures are below the
boiling point for a certain fraction of the packages. This happens to be
for the mean infiltration, mean thermal conductivity case. There would
even be more packages in that initial seepage possibility realm if I
looked at the high thermal conductivity/high seepage case.

So, there is a possibility of initiating some seepage during what has
been called the thermal pulse period on some packages that may happen to
be at the edge of the system. But it\'s a low probability. And,
generally, during that period, there is no seepage if the temperatures
in the drift wall are above boiling, as Bo pointed out in the bases Bo
presented.

Once we get past that time period which, you know, is in the first 100
to 1,000 years-ish, so a few percent to up to 10 percent of the
regulatory time period, we are into the seepage representation, which
has factored into it the change in percolation flux associated with
changes in climate. So, the fraction of seepage goes up and the fraction
of waste packages that potentially see seepage goes up. And Bo presented
the bases for that.

All of these result in a range of possible seepage rates and amounts
that vary across the repository block. And those ranges, you see an
example of that range in the lower left-hand corner, and the uncertainty
in that range, which is based on the upper left-hand corner, have been
incorporated in the assessment of post-closure performance. Let\'s go
onto the next slide.

Okay. We then went on to Carl. As I said before, we broke it up into two
parts; during the thermal pulse and, if you will, after the thermal
pulse. And as Carl pointed out, we have no observations anywhere in the
mountain or around the mountain of any calcium or magnesium chloride
salts. That\'s not to say that calcium or magnesium chloride salts
don\'t exist anywhere. They clearly exist some places. And, in fact,
there have been some observances of it in the High Sierras, as Carl
said. But you\'ve got to get that salt somehow to Yucca Mountain, which
means it can never have seen a humidity above 20-ish percent, the
deliquescent relative humidity for calcium/chloride type salts as Carl
had. Or the likelihood of that salt somehow getting to Yucca Mountain
never having seen a 20 percent humidity, you know, given day-to-night
fluctuations, is essentially zero.

So, the possibility of getting a calcium/magnesium chloride salt sitting
on a waste package, we think, is essentially zero. Even if it did occur,
as Carl pointed out, it quickly is unstable and would quickly become
stable with chemical reactions with other constituents, with CO~2~,
etcetera, and H~2~O vapor. Even if those salts were present, as Carl
pointed out, they would quickly volatilize. Essentially, Carl\'s\--the
first three bullets here which Carl walked through are the same as\--let
me go\--I\'m not sure where we put it, John. We put it on this slide?
No. The EPRI\'s\--no. EPRI\'s all three\--three things.

Anyway, the first three slides that we have on there essentially are the
nos or highly unlikelies that EPRI identified. So we don\'t think the
calcium/magnesium chloride exists or is stable, which are nos on their
diagram. Well, maybe it\'s, I guess, the first two nos. And that given
the open system that it would evolve, would volatilize, especially at
the high temperatures, and the acid gas would be dispersed very quickly
into the repository block. So, let me go onto the next slide, if we can
get out of the EPRI conclusions. Okay, thanks.

Now, we\'re talking about the seepage part and the chemistry evolution
in the rock and the evolution of that chemistry in the drift when that
water seeps into the drift. The chemistry evolution, I think as Carl
pointed out this afternoon, was based on direct in-situ observations and
models and supported also by smaller scale laboratory tests. The
evolution of that pore water, even though it is complex, when you
simplify it to look at a few key constituents within that water, for
example, fluorides or nitrate/chloride ratios, can fairly readily be
explained. And the bases for that evolution from the rock into the
drift, and it\'s evaporation in the drift, and changes in concentration
within the drift, I think Carl gave a very excellent presentation trying
to integrate how those chemistries evolve.

Just stepping back a little bit, we realized that last May, sometimes
the abstraction process in TSPA can appear complicated and we may
over-complicate it somehow in how we present it because there was quite
a bit of discussion, as I recall, last May of binning of waters of
different types and how those bins evolve and things like that. We
clearly didn\'t talk about bins in this meeting. We talked about how the
chemistry evolves, not how the abstraction of different water types is
grouped together into like compositions. So, it\'s probably easier to
explain when you look at a water composition and how that water
composition evolves rather than the whole family of potential conditions
that the binning process that we talked about last May leads to.

I think, as Carl pointed out, the initial aqueous chemistries with the
exception of one which is the W-0 type water, the HD perm type water as
presented, all evolve into a sulfate or bicarbonate type brine; varying
degrees of nitrate/chloride ratio, as Carl presented, and talked then
about the importance of that nitrate/chloride ratio and total chloride
concentration when we got to the discussion of corrosion.

It\'s important to point out, Bullet 4, that those brines, even if they
exist in the rock, which they do, and come into the drift, which they
might with some probability, there is still a drip shield there. So the
degradation characteristics of the drip shield, which we did not talk to
you about today, but the degradation characteristics of the drip shield
then come into play, which affect the probability of that chemical
constituent getting into direct contact with the Alloy 22.

This range of chemical conditions in the aqueous phase and the
evaporation of that chemistry within the drift has been incorporated
within the TSPA. If I can go on to the next slide. Okay, I think I also
have one from\--well, let\'s just skip over that. I thought I had one
from Roberto Pabalan. I do? Okay. With his conclusion slides from
yesterday.

I think it\'s important to point out that it was interesting, I felt,
yesterday that EPRI sort of focused on the deliquescent part of the
Board\'s question, and NRC sort of focused on the seepage and brine
evolution part of the Board\'s question. I think they both recognize, as
we do, that they are two different sets of conditions and you have to
evaluate them separately because they are different chemistries.

So, I think what Roberto concluded yesterday was that he had a time
period, he called it Environment II, Joe Payer called it Environment IV,
where there is a potential for a chemistry existing that can lead to low
nitrate/ chloride ratios and which with those potentials have a
potential for, depending on the temperature, conditions of initiating
localized corrosion if they contact the waste package and they
concentrate. So, you have to have all those ifs lined up, which we\'ll
get to in a second, but they identified same conclusion, I think, that
Joe had and Carl had, that there is a window of environments where the
nitrate/chloride ratio can be low enough and the chloride concentration
can be high enough that the potential for initiating localized corrosion
occurs if that contacts the waste package.

Let me go onto the next slide. So, it\'s consistency in the conclusions
there, I believe, even though we\'re obviously coming at it from very
different approaches and even different data sets in some cases.

This was a discussion of how much water are we talking about when it
comes into the drift. It starts out as 20 to 40 liters per year. Those
are kind of the mean rates for a mean seepage when you have the
monsoonal climates and the glacial transition climates. So, we\'re
already focused on this time period out beyond 600 years. At time
periods less than 600 years, the values are about a tenth of that,
roughly. But that water then has to concentrate and evaporate, so then
you\'re down to, as both Carl and Joe said, you\'re down to milliliters,
to tens or 100 milliliters, of water per year per package to get that
degree of concentration to increase the chloride concentration, and the
nitrate chlorides are more or less going hand-in-hand as they evaporate.

This range of volumes, both in the seepage side and range of composition
concentrations in the aqueous side, are included in the TSPA model. So,
this uncertainty and variability of these aspects are included directly
within the assessment of performance.

Going to the next slide which get into the corrosion part, Joe\--I
can\'t follow up Joe, to be honest with you, so I might just skip over
these, I think. I think it\'s important to say that we have
significantly additional data that Joe presented. Let me show, yeah,
let\'s keep that, the logic diagram that we have up there that show all
the things that have to have lined up with answers of, in this case, no,
before localized corrosion can be initiated. And that\'s even given the
discussion that we had associated with the conservativeness of the
critical potentials that are measured, given the crevices that both we
and the NRC used for the testing methodology for determining that
critical potential.

So, we have to go through all of these nos to evaluate the initiation of
localized corrosion. Joe then talked about, given it\'s initiated, will
it propagate? And there was\--there is some uncertainty associated with
that. Although there was some assessments done and there\'s literature
available that show the, if you will, the slowing of the propagation of
localized corrosion, given it\'s initiated, even in Alloy 22, and Joe
presented some of our own data that suggests that with the reduction of
the current, keeping a constant fixed potential. That particular process
has not been included in the TSPA.

So, within the TSPA, if a crevice is initiated by a certain
nitrate/chloride ratio with a certain temperature range for a certain
chloride concentration, and given the presence of the crevice, that
crevice will propagate through the waste package. So, the fact that, as
I think as Joe pointed out, additional research, additional analyses,
additional study of the effect of crevice propagation in Alloy 22 in
repository relevant conditions is still required to, if you will, take
full benefit for that particular process within the post-closure
performance assessment.

As Joe pointed out, the conditions to support localized corrosion, given
that logic tree, are only possible during Period IV, and only if the
nitrate/chloride ratio is less than some critical value where there\'s
some uncertainty in that critical value, if the temperature\'s greater
than some critical value where there\'s some uncertainty in what that
value is, if the corrosion potential is high enough, I mean, there\'s
some uncertainty on what the corrosion potential is, and if severe
crevices are present, and there\'s uncertainty in that. So, the
uncertainty in all of these aspects, i.e., where is this boundary? I
think Dr. Latanision asked is 90 degrees a fixed, hard, fast, you know,
in-the-sand kind of point where below which there is no localized
corrosion? And Joe correctly answered no. There\'s uncertainty in where
that point is. I mean, that uncertainty is a function of the
environment. It\'s a function of the chemical environment in particular.
So, that uncertainty is being factored into the system assessment.

I believe I stuck in here a slide from when Darrell Dunn. He kind of had
the similar conclusions as Joe\'s. Passive corrosion rates should depend
on temperature and similar conditions, we agree with that. Accelerating
uniform corrosion has been observed. Localized corrosion depends on the
chloride concentration and the concentration of inhibitors, the
temperature, and the metallurgic condition. And that bullet is certainly
true.

Those factors, the metallurgic conditions, the weld conditions, if you
will, the inhibitors, the chloride concentration and temperature are all
factored into the probability of initiating localized corrosion based on
the data that you\'ve seen from NRC and that you\'ve seen from Joe. And,
as I say, Joe presented a subset of our data, but I think a
representative subset of the data used to make the conclusions
associated with that third bullet. And I think we also presented the
data that that confirmed from our perspective what NRC observed from
their own tests, from the Center\'s tests, with respect to the effects
of nitrate and carbonate and sulfate.

I don\'t believe the effects of sulfate we\'re taking credit for. We\'re
right now within the probability of initiating localized corrosion, but
the effects of nitrate are being considered. Let me go on to the next
slide.

Okay. Joe presented not all of the tests that were indicated here. And
not all of these, more than 200 open circuit potential tests and more
than 300 cyclic polarization tests, have been completed in the last nine
months, but I would have to guess and Tammy and Greg would have to
correct me that some two-thirds or three-quarters of them were completed
since the last May\'s Board meeting. So you are seeing a lot more data,
linear polarization data, cyclic polarization data, and there are more
data behind the data that Joe was presenting today.

Those data were focused in\--I think the question was excellent this
morning\--they focused in on the sodium chloride, sodium nitrate,
calcium nitrate type conditions that the in-drift chemical environment
that we believe was most likely to see. And it also focused in on trying
to detail out where the effects of nitrate, the effects of sulfate,
where there are beneficial effects, were no longer present or observed
with respect to the critical potential. So, we purposely focused the
testing program over the last six, eight, nine months on exactly those
environments, on exactly those nitrate conditions, over exactly the
temperature range that we felt was more relevant.

In addition, we have collected the data, not cyclic polarization data,
but some of the other\--the linear polarization tests, at even a higher
temperature. You saw the one data set there that went up to 220 degrees
Centigrade. Those data are still being collected at Livermore. Those
high temperature data are still being collected at Livermore as are
additional cyclic polarization tests over even additional chemical
environments.

So, we see a snapshot in time today just as we saw a snapshot in time a
year from now, but with a lot more information behind that snapshot and
a lot more integration of that information with respect to its relevance
to the degradation of the waste package container. I had some\--so if I
can just go to the summary slide, John.

I think the last report in November and the letter in October correctly
reflected the Board\'s understanding that they had based on the
information the Project and others had presented to them last May, but
there\'s additional information. Some of it directly focused at
answering the Board\'s questions. And I think we benefitted from the
hard questions that the Board asked to get some of the specific tests to
address specific questions completed.

We focused the testing program, which we had plans on doing anyway, on
the specific environment and uncertainty in that environment that\'s
more likely to evolve in the drift. And that additional information and
additional syntheses of information is what we saw today. We also, as I
have down here at the bottom, we did some additional analyses directly
focused at the particular questions that the Board asked. In particular,
the results that you saw from Bo with respect to the thermal seepage
tests, if you will, that NRC performed, we felt important to be able to
explain that test using our models, rather than having someone else
interpret it for us. And the relevance of that test using our models,
which we did.

We felt it important to explain and try to understand the environments
that the Catholic University tests were being performed under, and could
we evolve? And I think Carl had in one of his backup slides, he didn\'t
go into it, could we evolve thermodynamically a condition that looked
like pHs of .5, or zero, or minus .5, such as in the Catholic University
experiment? So we were, if you will, testing our own models and our own
understanding using the observations of others.

There\'s additional analyses the survey has performed, and Zell talked a
little bit about it and Carl presented it in his briefing on the dusts,
you know, to try to understand the soluble fraction in the dust, to look
at other places of dust in the arid Southwest and what those dusts look
like and how representative they are to our conditions in order to
answer the Board\'s questions. Next slide, John.

Okay, so now I\'m in conclusions. So, I believe the three presenters and
the healthy dialog during the discussion and presentations addressed the
questions and concerns the Board raised last November and October. We
did that with additional information and additional syntheses of
information. We used all lines of evidence we could get our hands on.

I think the Board has recommended to the Project numerable times to not
just rely on one aspect, not rely on just a model or something like
that, but\--or sensitivity analysis, but cover the full gamut of
possible lines of evidence to address a particular issue. And we did
that. We did that with additional tests. We did in-situ observations,
laboratory tests, models with additional sensitivity analyses, and with
comparison to alternative models, and, as appropriate, some natural
analogs that all three presenters presented to you; Bo with respect to
geothermal systems, Joe with respect to the use of Alloy 22 and other
industrial applications, etcetera.

We conclude from all of this, not surprisingly, the same conclusion we
had this morning, that the conditions necessary for widespread localized
corrosion will not occur during the thermal pulse for all the reasons
that we laid out throughout the day, mostly focused on the deliquescent
and brine seepage evolutions. The chemistry and temperature are such
that the possibility of initiating localized corrosion during the
thermal pulse is extremely unlikely. After the thermal pulse, we have a
period, this Period IV in Joe\'s talk and Period II in the NRC\'s talk,
where the possibility of initiating localized corrosion, given a number
of if statements occur, could occur.

Finally, on the last slide, the uncertainty in all of the above, which
of course there is, has been or is being included within the total
system performance assessment. The effect of that uncertainty will be
evaluated as part of the performance assessment, if you will, the
post-processing of the results and the evaluation of what the results
are. And we\'d be happy to present that to the Board in September, and I
think we have planned a two-day or some number of day meeting on that
particular subject.

And when we do that, I think it would be worthwhile just to come up
several times here to talk not only about performance assessment, but
also talk about performance confirmation. You know, another key element
of the license application is to talk about the requirements. I think
Tim McCartin mentioned it earlier, half an hour ago, the requirement of
performance confirmation. It is a requirement, and it will be in the
license application, and the specific tests that are required to meet
that requirement will be identified. And I think probably September time
frame would be a good time.

The revision of that is in review right now within the Department. And
there\'s some dialog back and forth between the Department and ourselves
on getting that final performance confirmation plan which uses the bases
for Section 4 of the Safety Analysis Report completed within the next
couple of months.

So, with that, I\'m going to stop. I took a little longer than my 15
minutes.

LATANISION: No, thank you, Bob. That was very helpful.

I think we should take a few minutes for the Board to ask questions if
you have any that you\'d like to address at this point. Mark?

ABKOWITZ: Abkowitz, Board.

LATANISION: Hold on.

ABKOWITZ: Abkowitz, Board. Abkowitz, almost electrocuted member of the
Board.

I wanted to start, Bob, by making a correction to one comment that you
made. To my knowledge, no Board member has suggested that they would be
comfortable with a hotter design than what you have proposed. The
context of that was a question that I asked you which was given how
emphatically you believe that corrosion is a non-starter, and that that
was a line of defense that no\--perhaps was not being eroded into, then
why not go to hotter design. I was more questioning your confidence\--

ANDREWS: Okay.

ABKOWITZ: \--not any particular position that I had.

ANDREWS: Okay, thanks for the clarification.

ABKOWITZ: I did want to run through a sort of a different type of
decision or logic tree, and would like to ask you to react if you would.
And it goes somewhere along these lines. It starts off with the question
which is a riskier environment from a safety performance standpoint, a
cold design or a hot design? And I\'ve yet to hear an argument for why a
cold design presents a higher risk.

I think I\'ve heard information over the last couple of days to suggest
that we are further along the learning curve in terms of whether or not
a hotter design presents a particular risk with regard to corrosion. I
think I\'ve also heard that this is a very complex process with many
different scenarios and much conceptual development that\'s underway.
So, we may be narrowing the risks that\'s presented by that, but I
don\'t know whether we\'ve totally resolved it. So, from a decision tree
standpoint, the question of which design is less risky, cold or hot, one
would go into the direction of cold is less risky.

So, then you go to cost benefit analysis and you ask the question, you
know, is there a benefit/cost ratio here that suggests that we have some
kind of tradeoff between risks and costs? And, obviously, that\'s an
important question from any standpoint because we\'re always into that
tradeoff. And from what I\'ve been told from previous work that DOE has
done and shared, that the overall economic cost of each option are
relatively the same; effectively, a wash is what I\'ve been told.

And so then we come to the conclusion that if one design is less risky
than the other and they both cost the same, the conclusion one has to
reach is that agency ego is dominating common sense. And, therefore, the
only question that\'s left on the table, given the stage that we\'re in
right now, is whether the period of time that\'s necessary to make the
design decisions to go to a lower risk, higher benefit/ cost alternative
is worth the tradeoff versus the thousands of years of improved safety
performance. And that\'s the question on the table. So, I would just
like to ask you to react to that decision tree.

ANDREWS: Okay. I appreciate the question. Let me talk about the risk
part of it, which is something I know about and I\'ll leave somebody
else to talk about the cost part of it and the cost benefit analysis
that the Project, the program, the country has to go through with that.

On the risk side, there\'s not a clear indication, you know, right now
sitting here with our current models, current understanding, current
range of potential thermal hydrologic responses, thermal seepage
responses, chemical responses, drip shield responses, that it\'s a slam
dunk that colder would be better, if you will, from a dose risk
perspective. One could make arguments depending on how you went to that
cooler design, in fact, the risks went up. They would go up with respect
to things like the probability of a igneous intrusion dike intercepting
the repository block, just from a flat out geometric area perspective,
if that\'s how you went to a cooler design. There\'s clearly other ways
to go to a cooler design.

But I think we saw both in the way Joe presented this range of
potential, and I want to emphasize potential, susceptibility for
localized corrosion, and the same way NRC identified this potential
range of potential susceptibility for localized corrosion, there is
uncertainty in where that point is. It\'s not a 90 degrees, you know,
flat out, we\'re 100 percent confident that everything below 90°C would
have no potential for localized corrosion. In fact, the Center presented
some data for, I believe, it was low nitrate/ chloride ratios at
significantly lower temperatures, you know, 60 degrees, 70 degrees
Centigrade, where the possibility at least appeared possible to initiate
localized corrosion at a lower temperature.

So, simply, I think in the Board\'s letter or report it said the
information available to us to date says below 95°C looks pretty good.
I\'m paraphrasing a little bit. I think the information available now
would say, well, at 95°C is probably not the cut line, but it\'s
somewhere with some uncertainty below that. And, during that time
period, there is going to be the possibility of thermal seepage because
you are clearly, the packages below 90 or 95 or 80, there is a
possibility for seepage to occur and the chemistry that had evolved in
the rock to get into the drift.

I think it was important, one of the things Carl pointed out with
respect to the chemistry evolution, is the chemistries are, more or
less, after a few thousand years. They\'re kind of evolving back to the
ambient chemistry. That ambient chemistry has some range on it, but some
of that range includes low nitrate/chloride ratios. Those low
nitrate/chloride ratios, even in the ending condition, were the
temperature to be 70°, 80°C to contact the package, could initiate
localized corrosion.

So, having said that, is it better from a post-closure risk perspective,
and I\'ll just focus on post-closure risk, from a post-closure risk
perspective to have some design that was cooler or some design that,
like we have, that\'s a little bit warmer? It\'s not at all clear that
one would be any better than the other. Then you have to factor in, of
course, the pre-closure risks. And maintaining an open facility for
longer, maintaining ventilation systems for longer, making a larger
repository have pre-closure risks associated with them, actual safety
risks; worker safety and other risks associated with that. So, you
can\'t divorce the decision making process from the pre-closure risks
either.

We\'ve kind of focused on one aspect here which is the next 10,000 years
rather the next 50 years during construction and operation. So, having
said that, from a risk perspective even though we haven\'t done the
quantitative analyses, I have to tell you, there\'s no \"a priority\"
precut answer that one would be demonstrably better given all the other
uncertainties than the other.

Now, on the cost part of it, probably someone in the Department should
talk the costs. I believe one was a little bit more costly, to be honest
with you. The lower operating mode was more costly depending on how you
developed the costs. And if you ventilated for 300 years versus
ventilating for 50 years, there\'s clearly some costs associated with
that. If you increased the area by a factor of two, clearly there\'s
some costs associated with that.

Joe, do you want to\--Joe Ziegler?

ZIEGLER: Yeah, this is Joe Ziegler, DOE.

I think that probably the most definitive thing on that was what was in
the EIS where we looked at a range of thermal operating modes. And my
recollection is, is there was a greater cost associated with the lower
temperature operating modes, and it was basically due to what Bob said,
is we extend the operation of the repository many, many years, then the
costs are going to go up. You extend the amount of excavation that you
do, the costs are going to go up. I can\'t remember the exact numbers. I
think it was in the range of 15 percent or so from one extreme on the
operating mode to the other one as far as temperature goes.

And I think the EIS also has got a fairly well documented quantification
of the environmental impacts including worker safety, occupational
safety, additional radon release from additional excavation which would
affect both workers and the public, and that\'s documented pretty well
in the final EIS.

LATANISION: Bob, thank you very much.

I think at this point, we\'ll turn to the closing comment period or
wrap-up statement period from the point of view of the other
organizations that are here. I understand that all of the EPRI folks
have left, and based on a short conversation with John Kessler, I
understand that they felt\--he felt that their comments had been
adequately described yesterday. So, apparently we will not have any need
for a closing statement or wrap-up statement on behalf of EPRI.

I\'ll call next on Tim McCartin, from NRC.

McCARTIN: I\'ll be very brief. We thank the Board for the opportunity to
participate in the meeting, and I think we take the same approach as
EPRI. I think we explained our understanding yesterday and have nothing
further to add.

LATANISION: Okay. Thank you.

Maury Morgenstein, on behalf of the State of Nevada?

MORGENSTEIN: (Inaudible.)

LATANISION: Sure. Sure, by all means.

MORGENSTEIN: But they\'re quick ones. I\'d like to start out in
recognizing the fact that the Program really has come a long way,
especially since several years ago or maybe around the year 2000, I
don\'t remember exactly when, when the Program was sitting in J-13 in
the saturated zone in the laboratory looking at reactions that we deem
today clearly non-representative of the issues that are at hand. So,
we\'ve come a long way, but I don\'t believe that we are at the end of
the road, and I don\'t think that we should think because we now have
some basic understanding of what might be happening that we really do
have a full breadth of knowledge necessary, for example, for licensing.

Following that, the issue with regards to whether we, the State, would
prefer, if we had to have a repository, a repository that was deemed
cold or cooler, or one that was deemed, as it appears today, warmer, we
would unequivocally go to the cooler repository for a host of reasons
all of which can be summarized by several issues of which can be
summarized by one statement. And that is a cooler repository is one that
we could get down and understand.

It is manageable from the point of understanding the near-field
reactions. It is clearly unmanageable in the state of a hot repository.
Now, whether this results in a repository configuration that would cause
additional costs or there are other attributes that we need to factor
in, somebody has to do a cost benefit analysis. Do we want one that we
can rely on that\'s safer or do we want one that has less radon exposure
to the workers? But what are\--what are our considerations?

With respect to a hot repository, we believe that the Program has gone
somewhat astray on several items. If we, for example, went to Joe
Payer\'s excellent representation of the different stages and we went to
stage, I think, the hot\--the thermal stage, and that\'s probably stage
three, if I remember correctly, if I\'m wrong tell me what number it is.
But if we went to the thermal stage and we took a look at several
issues, maybe my point will be made a little bit clearer. Essentially, I
have four comments on the thermal stage.

One, we saw that the deliquescent salts that were studied or looked for,
which are essentially calcium-chloride/magnesium-chloride, were not
deemed to be reasonably expected and in the salt packages that we see in
the dust. There was no mention of nitrates. No mention of an attempt to
look at, say, magnesium nitrate. Yet, we are all clear that magnesium
nitrate salt deliquesces and that if you put C-22 in it, C-22 reacts and
corrodes.

I mean, we have presented this information so that we know that it\'s a
bad player. Not all nitrates are, in fact, inhibitors. They may be
inhibitors under conditions of local corrosion, but under conditions of
general corrosion, they appear not to be, at least in some concentrated
circumstances, and that\'s really what we\'re looking at. We\'re looking
at deliquescent salts on a metal surface. Yet, we ignored the major
player. So, we\'re not ready to give up the thermal period from the
point of view of dust. We don\'t think that the analyses have been
adequate at present.

The other major issue that really troubles us is the concept of seepage.
In almost all cases, we\'re looking at the mean seepage, and our
understanding of seepage events is that they are going to be episodic.
When we go in the field in the summertime or even in the\--well,
dominantly in the summer, we get rained on. And when we see floods at
Yucca Mountain, I\'ve been out there and Forty-Mile Wash was completely
flooded, and actually there was a rowboat that went down Forty-Mile
Wash. Don\'t ask me where it came from, but it was very weird to see
this, and this was back in the 80\'s.

That is an extreme event. We do have extreme events almost on an annual
basis. It is those extreme events that produce water in the repository.
It\'s not the average annual, mean annual, rainfall or infiltration. If
we concentrate on the extreme events and then concentrate on the vapor
barrier, which is purported to exist around the opening of the tunnels,
we can overcome the vapor barrier during the thermal period under two
conditions: one, sufficient head in a fracture system that carries
water, certainly not one that doesn\'t carry water, so it will be not
all over the repository; two, if there\'s a high enough salt content in
the vadose water coming through.

So there are two clear conditions in which we can go through the vapor
barrier and produce water in the near-field. If we can produce water in
the near-field, and that water contains solute, and it evaporates on hot
metal surfaces, whether it be the drip shield or canisters or both,
during the thermal period, we can have serious reactions in the
repository much more so than we would under cooler repository
conditions. We consider this extremely serious, yet we do not see the
Program focusing in this area.

With respect to the\--and, essentially, my final comment, with respect
to the other end of the temperature scale, we don\'t see any cutoff
point. There may be one and probably there\'s likely one with respect to
localized corrosion. We do not view localized corrosion as the only
significant means of corrosion in the repository. We have reason to
believe based on tachyhydrite reactions and formation reactions that we
will, at least, see temperatures from 65 degrees to 140 as being very
significant. Tachyhydrite is only one of a multitude of salts that we
have looked at now that show strong reactions; strong reactions under
conditions of 1X pore water, unconcentrated, dripping on hot metal
surfaces. No preconceived Soxhlet experiments. Simple hot plate.

You have to have some humidity. It\'s very important. Without which if
it\'s totally dry, no reactions. So that there are some conditions
necessary. These conditions seem reasonable. They\'re not outlandish.
They fit within the confines of a cold repository as well as a hot.
Under the conditions of a hot repository, if you form deleterious salts,
which you\'re likely to do, those will stay active probably through the
full period of confinement.

Thank you very much.

LATANISION: Let me ask if the Board has any comment or question to
follow up?

(No audible response.)

LATANISION: Anyone from the audience want to respond?

(No audible response.)

LATANISION: In that case, Mr. Chairman of the Executive Committee, I
pass the baton to you for a wrap-up on behalf of the Board.

DUQUETTE: This will take about 10 seconds, but I do want to thank
everyone who participated in the meeting. I especially appreciate
comments from the public in this particular case.

As everyone in the room knows, the Board\'s mission is to evaluate the
technical and scientific validity of DOE activities. So, we especially
look forward to hearing from DOE on the new data and research on this
subject. We did give DOE some latitude to put together today\'s agenda,
and it\'s clear that a lot of hard work in developing new data and
developing new concepts and in making the presentations went into their
effort.

We especially appreciate the Nuclear Regulatory Commission, EPRI, and
the State for participating in the meeting, although you\'re not
required to, of course; only the Department of Energy is when we hold
these meetings. So, we really appreciate your efforts and your
presentations.

The discussions over the last couple of days gave the Board a lot to
think about. The meeting started out, of course, to just address the
thermal pulse. We\'ve gone way beyond that, and we appreciate that. I
think we\'ve gotten a lot of good and new information from it.

Bob Andrews did say that the information presented today answers the
questions raised by the Board. I\'m not sure that that\'s entirely
correct at this point. As is our practice, we will review everything
we\'ve heard, the new data that comes with it, and we will, of course,
report in a letter to Margaret when this meeting is over with.

And so with that, I think the meeting is concluded. I want to, once
again, thank you all for your participation, and it\'s cocktail time.

(Whereupon, at 6:38 p.m. the meeting was concluded.)