Official Transcript of Proceedings

NUCLEAR REGULATORY COMMISSION

Title: Advisory Committee on Reactor Safeguards

585th Meeting - Open Session

Docket Number: (n/a)

Location: Rockville, Maryland

Date: Wednesday, July 13, 2011

Work Order No.: NRC-1012 Pages 1-194

NEAL R. GROSS AND CO., INC.

Court Reporters and Transcribers

1323 Rhode Island Avenue, N.W.

Washington, D.C. 20005

(202) 234-4433
DISCLAIMER

UNITED STATES NUCLEAR REGULATORY COMMISSION’S 

ADVISORY COMMITTEE ON REACTOR SAFEGUARDS

The contents of this transcript of the proceeding of the United States Nuclear 

Regulatory Commission Advisory Committee on Reactor Safeguards, as reported 

herein, is a record of the discussions recorded at the meeting. 

This transcript has not been reviewed, corrected, and edited, and it may contain 

inaccuracies. 
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1 UNITED STATES OF AMERICA

2 NUCLEAR REGULATORY COMMISSION

3 + + + + +

4 585TH MEETING

5 ADVISORY COMMITTEE ON REACTOR SAFEGUARDS

6 (ACRS)

7 + + + + +

8 OPEN SESSION

9 + + + + +

10 WEDNESDAY

11 JULY 13, 2011

12 + + + + +

13 ROCKVILLE, MARYLAND

14 + + + + +

15 The Advisory Committee met at the Nuclear

16 Regulatory Commission, Two White Flint North, Room

17 T2B3, 11545 Rockville Pike, at 8:30 a.m., Said Abdel18 Khalik, Chairman, presiding.

19 COMMITTEE MEMBERS:

20 SAID ABDEL-KHALIK, Chairman

21 J. SAM ARMIJO, Vice Chairman

22 JOHN W. STETKAR, Member-at-Large

23 SANJOY BANERJEE, Member

24 DENNIS C. BLEY, Member

25 MARIO V. BONACA, Member
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1 CHARLES H. BROWN, Member

2 MICHAEL L. CORRADINI, Member

3 DANA A. POWERS, Member

4 HAROLD B. RAY, Member

5 JOY REMPE, Member

6 MICHAEL T. RYAN, Member

7 WILLIAM J. SHACK, Member

8 JOHN D. SIEBER, Member

9

10 NRC STAFF PRESENT:

11 ZENA ABDULLAHI, Designated Federal Official

12 STEVE PHILPOTT

13 PETER YARSKY

14 MICHAEL SCOTT

15 TARA INVERSO

16 MICHELLE FLANAGAN

17 PAUL CLIFFORD

18 ANDREW CARRERA

19 DAVID ESH

20 CHRIS McKINNEY

21 LARRY CAMPER

22

23 ALSO PRESENT:

24 KEN YUEH

25
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1 A G E N D A

2

3 OPENING REMARKS BY THE ACRS CHAIRMAN ...... 4

4 SAFETY EVALUATION REPORT ASSOCIATED WITH

5 NEDC-33173, SUPPLEMENT 2, PARTS 1, 2, AND

6 3, "ANALYSIS OF GAMMA SCAN DATA AND REMOVAL

7 OF SAFETY LIMIT MINIMUM CRITICAL POWER

8 RATIO (SLMCPR) MARGIN .......... 5

9 BREAK . . . . . . . . . . . . . . . . . . . . . . 17

10 10 CFR 50.46(c) EMERGENCY CORE COOLING SYSTEM

11 RULEMAKING . . . . . . . . . . . . . . . . 17

12 LUNCH . . . . . . . . . . . . . . . . . . . . . 76

13 TECHNICAL BASIS AND RULEMAKING LANGUAGE ASSOCIATED

14 WITH LOW-LEVEL WASTE DISPOSAL SITE-SPECIFIC

15 ANALYSIS . . . . . . . . . . . . . . . . . 77

16 ADJOURN

17

18

19

20

21

22

23

24

25
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1 P R O C E E D I N G S

2 (8:29:00 a.m.)

3 CHAIRMAN ABDEL-KHALIK: The meeting will

now come to order. This is the first day of the 585th 4

5 Meeting of the Advisory Committee on Reactor

6 Safeguards.

7 During today's meeting, the Committee will

8 consider the following. One, Safety Evaluation Report

9 Associated with NEDC-33173, Supplement 2, "Analysis of

10 Gamma Scan Data and Removal of Safety Limit Minimum

11 Critical Power Ratio Margin." Two, 10 CFR 50.46(c)

12 Emergency Core Cooling System Rulemaking. Three,

13 Technical Basis and Rulemaking Language Associated

14 with Low-Level Waste Disposal Site-Specific Analysis.

15 And, four, Preparation of ACRS Reports.

16 This meeting is being conducted in

17 accordance with the provisions of the Federal Advisory

18 Committee Act. Ms. Zena Abdullahi is the Designated

19 Federal Official for the initial portion of the

20 meeting.

21 Portions of the session dealing with the

22 Safety Evaluation Report associated with NEDC-33173

23 may be closed in order to protect information

24 designated as proprietary by GEH.

25 We have received no written comments or
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1 requests for time to make oral statements from members

2 of the public regarding today's sessions. 

3 There will be a phone bridge line.

4 Members of the public will be listening to the

5 discussions regarding 10 CFR 50.46(c), Emergency Core

6 Cooling System Rulemaking.

7 To preclude interruption of the meeting,

8 the phone will be placed in a listen-in mode during

9 the presentations and Committee discussions. 

10 A transcript of portions of the meeting is

11 being kept, and it is requested that the speakers use

12 one of the microphones, identify themselves, and speak

13 with sufficient clarity and volume so that they can be

14 readily heard.

15 We will now proceed to the first item on

16 the agenda, Safety Evaluation Report Associated with

17 NEDC-33173 Supplement 2, "Analysis of Gamma Scan Data

18 and Removal of Safety Limit Minimum Critical Power

19 Ratio Margin." Dr. Banerjee will lead us through that

20 discussion.

21 MEMBER BANERJEE: Thank you, Mr. Chairman.

22 For those of you who were not here in

23 2007, I need to give you a little background, because

24 otherwise this will be a little obscure as to what we

25 are doing here.
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1 We considered at that time -- 

2 (Off the record comments.)

3 MEMBER BANERJEE: But in 2007, we

4 considered the matter of GE methods being applied to

5 MELLA+. Don't ask me what it stands for, but I can

6 tell you what it does. 

7 So, when you operate a reactor from say

8 100 percent through its stretch of 5 percent,

9 eventually to 120 percent, then this is called an

10 Extended Power Uprate, and we've dealt with a lot of

11 these. 

12 And, of course, what happens at that point

13 is that you're in a situation where you can control

14 the reactor by inserting and withdrawing rods, but you

15 lose the ability to be able to control it by

16 controlling flow, control the reactivity. So, what

17 MELLA+ tries to do is to take this 120 percent power

18 and allow you to go down to flows as low as 80 percent

19 of the rated flow at 120 power, and then between 80

20 percent of the rated flow and about 55 percent, or

21 thereabouts, the power has to decrease, and that

22 defines the top of the operating domain. I'm sure

23 they'll show you a picture or something.

24 So, this expanded domain now allows you

25 higher power to flow ratios. And this gives you, of
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1 course, more operating flexibility for the reactor,

2 which is a good thing, but it subjects the fuel to

3 greater demands. Let's put it this way.

4 So, to enable MELLA+, what GE did and

5 others as well, was come up with fairly innovative new

6 types of fuel designs which already had been tested

7 and things like that. And then they also designed the

8 detect and suppress system which -- because the system

9 becomes more susceptible to instabilities, it tries to

10 take care of this problem.

11 So, that was what it was all about. And

12 then they applied fairly old methods which were -- I

13 don't know if you want to say old methods, but let's

14 say approved methods, historically approved methods,

15 or accepted methods to these conditions of higher void

16 fractions that you get, higher flow ratios and so on,

17 which were somewhat outside the domain of these

18 methods that had been originally developed.

19 So, we went through a whole long exercise,

20 the Staff did, to look at the applicability of these

21 methods, and various mods, and so on. And we came up

22 with a letter somewhere in 2007 which we agreed with

23 the -- concurred with the Staff who had accepted these

24 methods with several conditions. 

25 I don't want to make this into a long
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1 preamble, but some of these conditions were additional

2 uncertainties that were put on critical power issues,

3 both the safety limit and the operating limit. Okay?

4 And some limitations where if you have to go to a new

5 fuel design, it had to all be looked at again, and so

6 on. And there was a lot of other conditions and

7 limitations put on ATWS and things like that, which I

8 won't go into right now, which was part of our letter.

9 Anyway, today we are dealing with two

10 uncertainties. One is associated with the safety

11 limit critical power ratio under EPU conditions.

12 Because of uncertainties in the -- let's say the

13 predictive capability of the various methods applied,

14 there was an additional uncertainty of .02 put on this

15 safety limit critical power ratio under EPU

16 conditions.

17 For MELLA+ conditions, which now is not

18 just 120 percent power, if you like, originally

19 licensed thermal power at rated flow, but goes down

20 through lower flows, like 80 percent of the flow at

21 120 percent power, can do that. 

22 Because of that, there was an uncertainty

23 which was put on MELLA+ conditions, which is this

24 expanded domain, which was .03. Okay? So, both those

25 limits could be, let's say, reduced -- both those
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1 uncertainties by new data, by proving that the methods

2 were sufficiently accurate. And that's -- those are

3 the two issues we are specifically addressing today.

4 Not the operating limit, CPR, not any of the other

5 conditions. Okay?

6 So, with that background, we have to

7 determine whether these uncertainties should be

8 removed which would, of course, give some operating

9 benefit. And we'll hear -- listen to what GE and the

10 Staff have to say. So, I'm going to turn it over to

11 Steve Philpott of the Staff, who will make some

12 introductory comments. We had a Subcommittee meeting

on June 7th 13 , and this is really the full Committee.

14 Okay, Steven, it's all your's. From now

15 on you run the show.

16 MR. PHILPOTT: Okay. Good morning. Thank

17 you, Dr. Banerjee. And good morning to everyone.

18 Again, my name is Steve Philpott, I'm a Project

19 Manager in NRR, responsible for working interaction

20 with GE-Hitachi in nuclear fuels, and managing the

21 topical report process.

22 Dr. Banerjee, you've done such a good job

23 of laying out the background, I'm not sure my

24 introduction is going to be all that needed, but I'll

25 step you through it just very, very briefly. And if
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1 you look on the agenda, I'll give you a very quick

2 overview of this review. And then we'll have GE3 Hitachi come up and make their presentation first,

4 followed by the Staff presentation.

5 MEMBER BANERJEE: And after you speak,

6 we'll go to closed session.

7 MR. PHILPOTT: Yes. Right after me, we'll

8 go -- GE-Hitachi's presentation does involve

9 proprietary information, so go straight to closed

10 session.

11 So, I have just a few slides and,

12 actually, kind of summarizes similar to what you said.

13 The interim methods when we approved the topical

14 report, I believe the SE was issued in January of 2008

15 for GE-Hitachi's interim methods, applying their

16 methods to EPU and MELLA+.

17 We have 24 limitations and conditions in

18 that Safety Evaluation, and GE-Hitachi has committed

19 to provide additional data to try to address and

20 remove some of those limitations and conditions.

21 Two of the limitations in that original SE

22 are what Supplement 2 aims to address, and what Dr.

23 Banerjee was referring to. Limitation 4 was this

24 additional .02 to be added to the safety limit minimum

25 critical power ratio for expanded or extended power
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1 uprate conditions. And Limitation 5 had an additional

2 .01 added to that .02, so a total of .03 for MELLA+

3 conditions. And both GE-Hitachi's and the Staff's

4 presentations will give you more details on that

5 breakdown to further explain that.

6 Supplement 2 requests removal of those two

7 limitations and conditions, does not request any other

8 changes to the limitations and conditions in the

9 Staff's original SE.

10 In the Subcommittee we went through --

11 kind of refresh the memory of the full roadmap. There

12 is a roadmap to get -- to address several of these

13 limitations and conditions and get to, I guess, an end

14 state which we would call kind of a final methods

15 approval where GE-Hitachi hopes to remove some of

16 those other ones.

17 The emphasis here is just to emphasize

18 again that Supplement 2 that we're addressing today

19 only addresses those two limitations that we just told

20 you about. And you see SE Appendix I, the approval or

21 the Safety Evaluation, if it's issued, would become

22 Appendix I to -- the way we're going to keep track of

23 all these is make them appendices to the original SE,

24 and have them all eventually in one larger document.

25 This Supplement was submitted in three
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1 parts based on three different Gamma Scan campaigns

2 which GE submitted in order to submit the additional

3 data to try to qualify -- 

4 VICE CHAIR ARMIJO: Steve, is there any

5 other supplement in the pipeline?

6 MR. PHILPOTT: There are -- right now

7 Supplement 1, which addresses the operating limit in

8 CPR has been submitted, and is currently being looked

9 at and reviewed by Staff. 

10 Supplement 4 is just about finished.

11 That's just a limitation plan. And Supplement 3, so

12 we're kind of going backwards in order, unfortunately,

13 in terms of numerical order. But Supplement 3 you saw

14 last year, which was -- extended the approval to GNF2

15 fuel, so that was approved.

16 Supplement 2 involved three cycles of

17 Gamma Scan Data, two from Cofrentes and -- bundle

18 Gamma Scan Data from Cofrentes, and one cycle pin-wise

19 Gamma Scan Data from FitzPatrick. 

20 And, again, this is -- as Dr. Banerjee 

21 mentioned, this was aimed at further qualifying the

22 methods and addressing some of the additional

23 uncertainties that -- the reason for these adders in

24 the first place were some of these uncertainties. And

25 you'll see more details in the Staff's presentation
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1 about that, as well.

2 And that gives you a very broad overview.

3 I don't want to spend too much time in this

4 introductory stuff. I'll turn it -- unless there's

5 any other questions for me, I'll turn it over to Dr.

6 Brian Moore from GE-Hitachi.

7 MEMBER BANERJEE: We should close the

8 meeting at this point.

9 CHAIRMAN ABDEL-KHALIK: Is there anybody

10 on the phone? We need to make sure that the phone

11 line is closed.

12 MR. PHILPOTT: I don't believe so.

13 MEMBER BANERJEE: So, we go into closed

14 transcripts.

15 MR. PHILPOTT: Okay. 

16 (Whereupon, the proceedings went off the

17 record at 8:43:17 a.m., to begin Closed Session, and

18 went back on the record at 10:22:25 a.m.) 

19 MEMBER BANERJEE: All right. Go ahead,

20 Peter.

21 MR. YARSKY: All right. I hope to go

22 through this material relatively quickly.

23 The IMLTR Supplement 2 sought to remove

24 two penalties applied to the SLMCPR, one for EPU

25 operation and one for MELLA+ operation, and sought no
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1 other changes to the conditions and limitations in the

2 Staff's SE. 

3 As we talked about, the Staff review

4 considered the Gamma Scan results, the TIP data,

5 comparison with key operating parameters, LPRM

6 calibration, and the applicability of MELLA+

7 operation.

8 In conclusion, Limitations 4 and 5 of the

9 Staff's SE for the IMLTR impose adders. GEH requested

10 the NRC review and approve Supplement 2 to remove

11 these limitations. Based on the Staff review, the

12 Staff concurs with GEH with one exception, and that is

13 the Limitation 5 which imposes a 0.03 adder to the

14 cycle-specific SLMCPR, while it is revised is only

15 reduced to 0.01, as opposed to being fully removed.

16 And Limitation 5 will now stipulate an adder of 0.01

17 for MELLA+ operation. That's all I have for

18 concluding remarks.

19 MEMBER BANERJEE: Thank you very much.

20 GE, are there any remarks you want to make?

21 MR. MOORE: This is Brian Moore. GE

22 prepared the Supplement to demonstrate the resiliency

23 of our methodology; hopefully, answering many

24 questions that were raised in 2007. A great deal of

25 effort was made by both GEH, and also our customers,
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1 to obtain this data set presented to the Staff. Thank

2 you for the questions both from the Staff and from the

3 ACRS panels. We believe that it has helped clarify

4 the record. Thank you.

5 CHAIRMAN ABDEL-KHALIK: None of the data

6 that was presented today covered conditions that would

7 be considered MELLA+. So, why are we just looking at

8 the differential adder, the .01, rather than the .03

9 for MELLA+?

10 MR. YARSKY: What I covered in the closed

11 session was the nature of what comprises that 0.03.

12 CHAIRMAN ABDEL-KHALIK: But, nevertheless,

13 I fully understand that, but that didn't cover

14 conditions pertaining to MELLA+.

15 MEMBER BANERJEE: We are in open session.

16 CHAIRMAN ABDEL-KHALIK: I understand.

17 MEMBER BANERJEE: Right.

18 MR. YARSKY: I am trying to formulate an

19 answer that would be appropriate in open session.

20 MEMBER BANERJEE: If you wish, we can go

21 back to closed session.

22 VICE CHAIR ARMIJO: We can close it again.

23 MEMBER BANERJEE: We can close the

24 meeting, if you'd prefer.

25 CHAIRMAN ABDEL-KHALIK: Yes, if you'd
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1 like, because this is a central issue in my mind.

2 MEMBER BANERJEE: Perhaps, why don't we

3 close the meeting for five minutes.

4 CHAIRMAN ABDEL-KHALIK: Right. That's

5 fine.

6 MEMBER BANERJEE: Okay?

7 CHAIRMAN ABDEL-KHALIK: Okay.

8 MEMBER BANERJEE: Can we do that, go into

9 closed session. Zena, please insure that we are -- 

10 CHAIRMAN ABDEL-KHALIK: Please.

11 MEMBER BANERJEE: -- in closed session.

12 Thank you.

13 (Whereupon, the proceedings went off the

14 record at 10:25:47 a.m., and went back on the record

15 at 10:28:46 a.m.)

16 MEMBER BANERJEE: Okay. So, Mr. Chairman,

17 we are done, and I'd like to thank both GE and the

18 Staff for a very complex matter well explained.

19 CHAIRMAN ABDEL-KHALIK: Thank you.

20 MEMBER BANERJEE: Thank you.

21 CHAIRMAN ABDEL-KHALIK: Thank you very

22 much.

23 At this time, we are scheduled for a 15-

24 minute break, so we will reconvene at 10:45.

25 (Whereupon, the proceedings went off the
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1 record at 10:29:08 a.m., and went back on the record

2 at 10:44:45 a.m.)

3 CHAIRMAN ABDEL-KHALIK: We are back in

4 session. At this time, we'll move to Item 3 on the

5 agenda, 10 CFR 50.46(c), Emergency Core Cooling System

6 Rulemaking. And Dr. Armijo will lead us through that

7 discussion.

8 VICE CHAIR ARMIJO: Okay. Mr. Chairman

9 and members, as you recall a few weeks ago we reviewed

10 a number of regulatory guides related to cladding

11 embrittlement. The objective there is to assure that

12 we have coolable geometry in the core in the event of

13 a loss of coolant accident. The issues there address

14 the potential fracture of undeformed fuel rods

15 resulting from embrittlement due to oxidation and

16 hydrogen.

17 Today we're going to talk about a part of

18 the fuel rod that is already fractured. In fact, it

19 has ballooned and burst, and that is also in the core

20 and has to be addressed as part of the ECCS

21 Rulemaking. So, this is strictly a briefing. The

22 Staff has not requested a letter on the matter. But,

23 of course, it's up to the Committee to determine what

24 we will do.

25 So, I would like to turn it over to the
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1 Staff, and I believe that's going to start off with --

2 where is Ms. Gibson? Oh, please go ahead.

3 MR. SCOTT: Thank you. Good morning.

4 Contrary to the agenda, I'm not Kathy Gibson.

5 Unfortunately, Kathy couldn't be here today. I'm Mike

6 Scott. I'm the Deputy Director in the Division of

7 Systems Analysis in the Office of Nuclear Regulatory

8 Research.

9 As Dr. Armijo discussed, this is the

10 latest in a series of interactions regarding the 10

11 CFR 50.46 rulemaking effort. We briefed the

Subcommittee on this subject on June 23rd 12 .

13 By way of background, in May 2008 we

14 issued a Research Information Letter entitled,

15 "Technical Basis for Revision of Embrittlement

16 Criteria in 10 CFR 50.46." It recommended that the

17 experimental results from our LOCA research program be

18 used as the basis for rulemaking to revise the

19 cladding embrittlement criteria in 10 CFR 50.46. Then,

20 in December of that year, we briefed you on the LOCA

21 research program findings and the rulemaking strategy

22 for the ECCS requirements. 

23 Since then, as you know, we have been

24 working on the rulemaking revisions. At the same time

25 we were completing an ongoing research program at
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1 Argonne and Studsvik specifically designed to

2 investigate the mechanical behavior of the ballooned

3 and rupture region. Today's briefing is on the

4 results and conclusions of this research program.

5 As we will discuss today, the results

6 indicate that the planned additional measures are

7 appropriate to address cladding behavior at high

8 burnup. The report documenting these results and

9 conclusions, along with the necessary updates to the

10 RIL will be provided as enclosures to the proposed

11 rule package that we're scheduled to brief you on in

12 February of 2012. So, the briefing today is intended

13 to familiarize you with this material in anticipation

14 of the future briefings.

15 A formal review of the information

16 presented today will be part of the proposed rule

17 package, so we are not requesting a letter on this

18 subject at this time. However, as always, the

19 Committee's feedback is welcome.

20 So, let me introduce the Staff who are

21 here today to brief you, most of whom I'm sure you

22 already know; Tara Inverso of the Office of Nuclear

23 Reactor Regulation, Division of Policy and Rulemaking

24 will begin today's briefing with the status of the

25 rulemaking project. Following Tara, Michelle Flanagan
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1 of the Research Staff will present a briefing on the

2 results and conclusions of the research program, and

3 will discuss how these results and conclusions are

4 being used to support the treatment of the ballooned

5 and ruptured regions in the proposed rule. John

6 Voglewede, our Senior Level Advisor for Fuels in the

7 back, and Paul Clifford from NRR next to me are also

8 here to answer questions, as needed.

9 So, with that, I'll turn the floor over to

10 Tara.

11 MS. INVERSO: Thank you. As Mike

12 mentioned, my name is Tara Inverso, and I'm the

13 Project Manager for the 50.46(c) rulemaking. And as

14 he also mentioned, we're here today to present the

15 regulatory basis which informs regulatory treatment of

16 ballooned and ruptured regions of the fuel rod within

17 the proposed 50.46(c) rulemaking. And as Mike also

18 mentioned, this is for familiarity in preparation for

19 the briefings on the complete proposed rulemaking

20 package later on this calendar year.

21 Today's meeting will begin with this

22 presentation, which is an overview of the rulemaking

23 activities, and will go directly into Michelle's

24 technical presentation. The industry will then remark

25 on the technical document that was made publicly
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1 available prior to the Subcommittee meeting. And it

2 will conclude with a discussion led by the ACRS

3 members.

4 This rulemaking has four main purposes.

5 The first is to incorporate findings of the fuel

6 cladding research program, and that research program

7 focused on high exposure of fuel cladding under

8 accident conditions, and identified previously unknown

9 embrittlement mechanisms, and also expanded NRC's

10 knowledge of previously identified mechanisms.

11 The Commission has also provided direction

12 on this rulemaking through an SRM, SECY-02-0057. They

13 directed the Staff to replace the prescriptive

14 analytical requirements within 10 CFR 50.46 with

15 performance-based requirements. And in developing the

16 performance-based requirements, they directed the

17 Staff to expand the applicability of the rule to all

18 cladding materials. Right now, the current rule

19 limits the cladding materials to zircaloy and ZIRLO.

20 And the Staff is also expanding applicability to all

21 fuel designs.

22 That last objective was also requested

23 through a Petition for Rulemaking which was admitted

24 in March of 2000 by the Nuclear Energy Institute, and

25 docketed as PRM-50-71. 
22

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1 And lastly, there's another Petition for

2 Rulemaking that this proposed rulemaking will address.

3 That's PRM-50-84, which was submitted by Mr. Mark

4 Leyse in March of 2007. And he requested that the NRC

5 require licensees to consider the effects of crud on

6 the fuel cladding.

7 Recent developments, the Office of Nuclear

8 Regulatory Research has drafted three draft reg

9 guides. We presented those to the ACRS Subcommittee

on May 10th, 2011, and the full Committee on June 8th 10 ,

11 2011. Those three, the first one establishes a test

12 procedure for measuring breakaway oxidation. The next

13 one establishing a test procedure for closed quench

14 ductility, and the last one establishes analytical

15 limits for zirconium-based alloys.

16 The Staff is continuing to evaluate the

17 results of fuel fragmentation and dispersion research.

We talked to the full Committee about that on June 8th 18

briefly, and again to the Subcommittee on June 23rd 19 .

20 We have no updates at this point on that phenomenon.

21 The purpose of today's briefing is to

22 discuss the mechanical behavior of ballooned and

23 ruptured cladding technical document.

24 As mentioned, we plan to brief the ACRS

25 Subcommittee on the full proposed rule package on
23

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December 15th 1 , 2011, and then return to the ACRS full

Committee on February 9th 2 , 2012. And we will deliver

the proposed rule to the EDO on February 29th 3 , 2012.

4 And that concludes the presentation. If

5 there are any questions?

6 CHAIRMAN ABDEL-KHALIK: Keep going.

7 MS. INVERSO: Okay. With that, I will

8 turn the presentation over to Michelle Flanagan.

9 MS. FLANAGAN: Okay. My name is Michelle

10 Flanagan, and I work in the Office of Research in the

11 Fuel and Source Term Team. And my presentation today

12 will cover the contents of a technical report titled,

13 "The Mechanical Behavior of Ballooned and Ruptured

14 Cladding." And the purpose of this document is to

15 serve as the technical basis for the treatment of

16 ballooned and ruptured cladding in the new rulemaking

17 for ECCS requirements.

18 And the presentation today will, for the

19 most part, follow the contents of the report. So,

20 we'll begin with a review of the regulatory history of

21 the balloon, and then we'll present the results of

22 NRC's integral LOCA Research Program, and then explain

23 how these results are being used to support the

24 treatment of the ballooned region within the

25 rulemaking to revise 50.46(b).
24

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1 So, if we look through the overarching

2 requirements of ECCS systems, we see the General

3 Design Criteria in 50.46 require an emergency core

4 cooling system is available to insure that if a loss

5 of coolant accident took place, the core could be --

6 remain in a geometry that's amendable to cooling, and

7 that decay heat is removed to insure long-term

8 cooling.

9 And in Commission hearings in the 1970s,

10 the coolable geometry was established as something

11 that could be maintained if the fuel cladding remained

12 ductile. And this position mostly fell out of the

13 belief that specific predictions and quantifications

14 of local loads wasn't possible, and that maintaining

15 cladding ductility was the best approach to preserving

16 coolable geometry. 

17 At that time, ring-compression data among

18 other experimental observations was used to establish

19 a ductility threshold, and that criteria that were

20 established were directly cited in the rule. And

21 that's where we have 17 percent, came out of that

22 testing program. 

23 And over 10 years ago, the question was

24 first posed, are these criteria that are in 50.46(b)

25 currently, are they appropriate for high-burnup
25

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1 cladding? And like the program that defined LOCA

2 acceptance criteria in 1973, the test program that we

3 embarked on to investigate high-burnup cladding also

4 used ring-compression tests, and largely followed the

5 same technical basis that had been established with

6 the original criteria.

7 And the conclusion of that test program

8 was that the oxidation criteria were not sufficient

9 for high-burnup cladding. And, particularly, what was

10 found was that hydrogen has a significant impact on

11 the cladding embrittlement. The greater the hydrogen

12 content, the less oxidation is required to embrittle

13 the cladding material. 

14 And then out of these findings, the Office

15 of Research issued RIL-0801, which cited a trend of

16 embrittlement oxidation as a function of pre-transient

17 hydrogen, and established a decreasing threshold as a

18 function of hydrogen.

19 MEMBER POWERS: When you add hydrogen into

20 zirconium, are you injecting or extracting electrons

21 out of the Fermi band?

22 MS. FLANAGAN: Am I injecting or -- 

23 MEMBER POWERS: Extracting electrons out

24 of the Fermi band?

25 MS. FLANAGAN: I don't know that. But is
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1 that -- is it a question of what leads to the

2 oxidation and the -- 

3 MEMBER POWERS: Well, the contention is

4 that hydrogen operates synergistically with oxygen to

5 enhance embrittlement. And when we think about

6 alloying of oxygen, we know that the FERMI band is

7 very sensitive in that alloy. And, in fact, most

8 alloying with zirconium we can explain what goes on in

9 the FERMI band. And one would think that oxygen and

10 hydrogen would act in opposite directions on the

11 electron concentration in the FERMI band. So, trying

12 to understand how it operates synergistically is

13 interesting.

14 MS. FLANAGAN: Yes. We didn't go into

15 that level of detail with what is going on at that

16 level. What I do know is that trends -- the larger the

17 hydrogen content, the greater the solubility for

18 oxygen, and the greater the diffusion -- or the faster

19 the diffusion of oxygen into the base metal is. So,

20 whichever way the FERMI bands would be for those types

21 of observations might be a conclusion that's

22 available. But those are the trends that we observed,

23 not in this research, but prior to this, and what we

24 know about the content of hydrogen and how it impacts

25 oxygen.
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1 Does that answer your question?

2 MEMBER POWERS: No.

3 (Laughter and simultaneous speech.)

4 MS. FLANAGAN: Right, but that's what we

5 know about hydrogen and oxygen, and how they're

6 related, and what kind of trends we see. And that's

7 why when we see increasing hydrogen content, what

8 we're really seeing is that oxygen is absorbed faster

9 into the base metal, and at more significant amounts.

10 And that's what leads to the embrittlement that we

11 observe, and that's why we see a decrease in the

12 amount of oxidation that it really takes to develop

13 brittle material.

14 MEMBER POWERS: Well, you know that when

15 the hydrogen goes into the alloy, you expand the

16 stability range to the beta region. Right?

17 MS. FLANAGAN: Yes.

18 MEMBER POWERS: And narrow the expanse at

19 the alpha region. Oxygen does exactly the opposite,

20 so I guess what you're saying is that oxygen is very

21 soluble in the body-centered cubic.

22 MS. FLANAGAN: I may be saying that. I

23 mean, basically, we're not observing the trends at

24 that level. We're looking for the material behavior

25 at a macroscopic level, what is the ductility? How
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1 brittle is the material? So, of course, all of that

2 is operating and it's at a level of understanding that

3 is underneath our observations.

4 So, this is the trend that we observed.

5 As I said, with increasing hydrogen we see that it

6 takes less oxidation to develop brittle behavior. And

7 with these results and RIL-0801 being issued an

8 interoffice working group was formed in order to

9 revise the regulations in 50.46.

10 And in developing that rule language, one

11 of the questions that the Staff focused on was how to

12 treat the portion of the fuel rod predicted to balloon

13 and rupture during a LOCA. And, in particular, the

14 Staff questioned whether the criteria that had been

15 observed in ring-compression tests was appropriate to

16 apply in the balloon region. And if we look at the

17 way that the balloon is treated in the current

18 regulations, it's articulated directly in the rule

19 language. And it says to take the oxidation limit and

20 apply it in the balloon where you're taking the thin

21 wall region, taking the average wall thickness and

22 using that as your denominator in your percentage of

23 cladding reacted. And then you're taking double-sided

24 oxidation. So, all that is specified in the rule.

25 It's how we say currently to apply the oxidation
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1 criteria in the balloon region, and so the Staff's

2 question was whether that was -- continued to be

3 appropriate with the new observations of the impact of

4 hydrogen.

5 So, there's a couple of unique features of

6 the balloon region which are really behind the

7 question that the Staff was asking. There is -- as I

8 mentioned before, there is a variation in the wall

9 thickness, so the rule language today says to take the

10 average of the wall thickness. And we can see that

11 with this large variability, you'll have some regions

12 which are thicker than the average and thinner than

13 the average, and you can imagine that the thinner than

14 average regions may be brittle.

15 In addition, we have seen large uptake of

16 hydrogen above and below the rupture opening, and

17 these regions are also observed to be brittle. So, in

18 the balloon region we have localized regions which are

19 known to be brittle. So, the question is whether our

20 oxidation criteria applied in the balloon region

21 preserves the necessary properties during a loss of

22 coolant accident.

23 I should mention that both of these

24 phenomenon were understood. The first to the left was

25 understood at the time that the original rule was
30

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1 written. It was clear that there was going to be non2 uniformity. And the second observation of high

3 hydrogen regions was observed in the `80s in programs

4 in the United States and Japan. And at the time that

5 the research results were evaluated, it was determined

6 that there was sufficient conservatism in the rule

7 that this -- the presence of these brittle regions was

8 acceptable, and no changes to the rule structure were

9 made at the time that these results were found.

10 MEMBER POWERS: I'm struggling to

11 understand the plot. 

12 MS. FLANAGAN: Yes.

13 MEMBER POWERS: What is red, and what is

14 blue?

15 MS. FLANAGAN: Oh, yes. Blue is the

16 hydrogen, and here we have tracked the -- each of

17 these measurements were made and tracked the hydrogen

18 content of the material. And it's a weight

19 percentage. The oxidation -- the oxygen is the ECR

20 value, or no. Here it's weight percent. The one

21 thing to note is that thinned walled regions the

22 presence of oxygen is going to be -- it's not -- it's

23 magnified I guess is the word, because of the thinned

24 wall. So, some of the increase in the center region

25 is due to the wall thinning.
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1 VICE CHAIR ARMIJO: But you don't have a

2 lot of hydrogen there.

3 MS. FLANAGAN: Correct.

4 VICE CHAIR ARMIJO: You make the point,

5 the hydrogen is all at the ends of the balloon region.

6 MS. FLANAGAN: Right.

7 MEMBER POWERS: As far as I can tell, at

8 zero there's no metal there either. That's what I

9 don't understand, is your picture has a gap, your

10 graph says there's no hydrogen there, which I can

11 believe, but there's a whole lot oxygen there.

12 MS. FLANAGAN: Yes.

13 MEMBER POWERS: But there's no metal -- I

14 mean, there's no material there.

15 VICE CHAIR ARMIJO: I don't think those

16 were the same samples.

17 MS. FLANAGAN: The value is an average for

18 a ring section, so it's -- 

19 MEMBER POWERS: If you look at the ring,

20 there's a gap.

21 MS. FLANAGAN: Okay. This is axial

22 distance, and then that's the circumference. So, I

23 don't mean to imply that these two figures are -- this

24 isn't measurements of this ring. This is just to

25 illustrate the rupture circumference. These are
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1 measurements that are made along the axial length, so

2 here is the burst center. And it would be the

3 elevation that this ring was taken. And then these

4 measurements are above and below. But this value is

5 taken of a whole entire ring.

6 MEMBER POWERS: Oh, it's all of that ring

7 at that level.

8 MS. FLANAGAN: Right. So, this would be

9 -- if I melted this down and I made a measurement of

10 the hydrogen and oxygen, that's where these two -- 

11 MEMBER POWERS: Now I understand.

12 MS. FLANAGAN: Okay. Sorry about that.

13 That may have been confusing. 

14 Okay. So, looking at the historical

15 treatment that the balloon region had, RIL-0801

16 commented that no criteria has been found that would

17 insure ductility in the cladding balloon. And further

18 stated that loss of ductility in the short portion of

19 the fuel region shouldn't lead to an uncoolable

20 geometry, as long as the amount of oxidation in the

21 balloon region remains limited in the current manner.

22 And when I say "in the current manner,"

23 I'm referring to the accommodations that are outlined

24 in the current 50.46 rule, where you're taking the

25 average wall thickness and you're doing double-sided
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1 oxidation.

2 So, the Staff and the Working Group

3 focused on how to document and support this conclusion

4 in the Statements of Consideration for the rule. 

5 VICE CHAIR ARMIJO: Now, back up,

6 Michelle. We're uncoolable geometry, and we have --

7 has the Staff put to bed the issue of the ballooning

8 causing loss of coolable geometry?

9 MS. FLANAGAN: As far as flow blockage?

10 VICE CHAIR ARMIJO: Yes.

11 MS. FLANAGAN: Yes, that's not handled

12 with this research. This research assumes a certain

13 balloon, and then looks at the mechanical -- 

14 MEMBER POWERS: I thought Rittenhouse had

15 done that back in the `60s or something like that.

16 MS. FLANAGAN: Yes. I'm not too familiar

17 with that, but it's done separately as a part of LOCA

18 analyses. 

19 VICE CHAIR ARMIJO: Okay. So, as far as

20 this rulemaking that's not an issue, or is it?

21 MS. FLANAGAN: I think I'll turn that

22 over to Paul just to be clear, but -- I mean it's not

23 in the -- 

24 (Simultaneous speech.)

25 VICE CHAIR ARMIJO: -- coolable geometry
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1 has all got to come together in one spot.

2 MR. CLIFFORD: Right. Yes, the purpose of

3 this research was really to look at the material

4 strength, material ductility of high-burnup cladding.

5 There was no integral LOCA tests done to further

6 evaluate or inform the treatment of the balloon region

7 with respect to the geometry of the balloon. We still

8 rely upon existing reg guides -- 

9 MEMBER POWERS: Any changes in the

10 ballooning for high-burnup from in the geometry of the

11 balloon are actually in the direction of greater flow,

12 aren't they as you go to higher burnup?

13 MR. CLIFFORD: Yes. I would imagine that

14 changes in hydrogen content in burnup irradiation

15 hardening would affect the size and shape of the

16 balloon. That's true.

17 MEMBER POWERS: The biggest balloons

18 you're going to get is on pristine clad, I would

19 think.

20 MR. CLIFFORD: Correct. And right now,

21 when they qualify a new cladding alloy they would do

22 separate effects testing where they would do balloon

23 testing to insure that their LOCA models were

24 conservatively treating the size and shape of the

25 balloon.
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1 MS. FLANAGAN: Okay. So, in an effort to

2 support the Staff discussion about the treatment of

3 the balloon region, the Working Group staff referred

4 to the results that were coming out of NRC's integral

5 LOCA research program. And in this program, tests were

6 conducted at Argonne National Lab, and Studsvik

7 Laboratory in Sweden. And in these tests single rods

8 were brought through a simulated LOCA transient

9 through heat up, oxidation at high temperatures,

10 cooled down to 800 degrees C, and then a quench

11 simulation.

12 And in these tests, particularly the tests

13 at Argonne where we used as-fabricated cladding, there

14 was a large range of balloon strains that were

15 investigated. And then -- and here's an image of the

16 test train that was at Studsvik to give a sense of

17 what it looked like experimentally.

18 After the tests, the segments that were

19 ballooned, and burst, and quenched were taken through

20 mechanical tests, which a four-point bend test which

21 subjected the entire span of the balloon length to a

22 uniform bending moment. And as I pointed out before,

23 we know that there are regions of high hydrogen

24 content, as well as the extremely thin region in the

25 center of the balloon, so having the uniform bending
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1 moment really allowed us to investigate where the

2 weakest location was, and investigate the competition

3 between the thinnest region, which has the highest

4 ECR, and the regions with high hydrogen content. 

5 And from the load-displacement curves of

6 the four-point bend tests we were able to analyze a

7 couple of parameters. One was to look at the maximum

8 plastic displacement as a measure of ductility.

9 Another was to examine the maximum applied energy as

10 a measurement of toughness. Another was to analyze

11 the maximum bending moment as a measure of strength.

12 And then, finally, in the tests we observed the

13 failure location. And I'll say a little bit more

14 about that next.

15 In comparing the load-displacement curves

16 and the parameters that we extracted from the load17 displacement curves between different tests, we were

18 able to investigate the influence of oxidation,

19 irradiation, balloon size, bend test temperature, and

20 hydrogen content.

21 So, I'm going to start with presenting

22 results that were conducted at Argonne National Lab,

23 and all of these tests were on as-fabricated cladding.

24 I don't intend to go through this table. I'll show

25 more usefully, or in a clearer way the results on a
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1 plot in which you'll be able to see some of the

2 trends.

3 Two things I want to point out while I'm

4 on this slide, though, is that the rupture strains in

5 these tests varied from 21 percent all the way to 70

6 percent. So, we had a large range of ballooning

7 strains.

8 Another thing I want to point out is that

9 all of these samples survived quench, so they survived

10 the quench process which produces its own significant

11 loads in both the hoop and axial directions. So, we

12 really want to point out that all of the samples had

13 some mechanical properties that were measured in our

14 test.

15 VICE CHAIR ARMIJO: Were they pre16 hydrided, Michelle?

17 MS. FLANAGAN: None of the samples on this

18 graph were pre-hydrided. We do have -- 

19 MEMBER CORRADINI: But there was another

20 group that you showed us that was, right?

21 MS. FLANAGAN: I have some plotted on the

22 graph.

23 MEMBER CORRADINI: Oh, that's what I

24 thought. Okay.

25 VICE CHAIR ARMIJO: Okay.
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1 MS. FLANAGAN: Yes.

2 VICE CHAIR ARMIJO: And this was all one

3 material, zircaloy?

4 MS. FLANAGAN: Yes, Zircaloy-4.

5 VICE CHAIR ARMIJO: Okay.

6 MS. FLANAGAN: No, sorry, it was ZIRLO.

7 Sorry.

8 VICE CHAIR ARMIJO: ZIRLO? That's what I

9 thought.

10 MS. FLANAGAN: Yes, it was ZIRLO, and it

11 was designed to be comparable directly to the material

12 at Studsvik, which was ZIRLO. That's what we had

13 available to test for irradiated material. 

14 So, as I said, there's an easier way to

15 show these results, and one of them is to look at the

16 bending moment as a function of the CP-ECR. So, here

17 we have all of the results plotted as a function of

18 oxidation level. And we notice that the general trend

19 is that with increasing oxidation we have a reduction

20 in the maximum bending moment.

21 I want to point out that on this slide we

22 have two sort of sets of data. We have the data

23 distinguished into two categories, and it's as a

24 function of large balloons and small balloons. So, we

25 have circles indicating very small balloons, or less
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1 than 40 percent, and greater than 40 percent, and then

2 squares indicating small balloons at less than 33

3 percent.

4 In addition, we have one data point that

5 was measured at room temperature, the bending test was

6 conducted at room temperature, while the other ones

7 were conducted at elevated temperatures consistent

8 with the ring-compression test data. 

9 And I'll point this out on the next slide,

10 but we have two different failure locations. And in

11 this plot, some of the points failed at the center of

12 the rupture opening, and some of them failed at the

13 location of maximum hydrogen content. And yet, we

14 have a general trend of as the oxidation increases the

15 bending moment decreases. So, we don't see a large

16 distinction between results that failed during -- at

17 the center of the burst opening, or at the region of

18 high hydrogen content.

19 So, as I said, we observed two types of

20 failure. On the left, we have samples which failed at

21 the high hydrogen regions. And, generally, these were

22 observed in rods that had very small balloon sizes.

23 VICE CHAIR ARMIJO: Very what? I didn't

24 hear you.

25 MS. FLANAGAN: Very small balloon sizes.
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1 VICE CHAIR ARMIJO: Okay.

2 MS. FLANAGAN: And, alternatively, we had

3 failure that occurred right in the center of the

4 rupture opening. And this was always the case for

5 large balloons, and then some of the small balloons

6 also had this failure location.

7 The values of failure energy were also

8 shown to decrease with increasing oxidation. And,

9 again, even through a wide range of values for

10 ballooning strain. 

11 So, following the as-fabricated cladding

12 testing program at Argonne, four irradiated rods were

13 tested at Studsvik in NRC's integral LOCAL research

14 program. And I should say that prior to testing at

15 Studsvik, we did a lot of work between Argonne and

16 Studsvik to compare their apparatus, to compare the

17 results that they were getting, and we used as18 fabricated cladding in both cases to benchmark the

19 equipment to insure that we when were done we could

20 really put all of these points on the same plot.

21 The sample material that we had available

22 at Studsvik was around 70 gigawatt-days per ton

23 burnup, and the hydrogen content was around 200 weight

24 ppm. So, given that the weight -- the hydrogen

25 content was 200, we targeted our testing at Studsvik
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1 to be just above and just below the values at which we

2 expect embrittlement based on our ring-compression

3 test results. And then we also conducted a test at 17

4 percent oxidation, and zero percent. So, basically, it

5 was ramp to rupture and then the test was terminated.

6 I want to say that the ECR value is a

7 calculated value, so in all of the results that I've

8 presented previously, and all of the ones that I'll

9 present following this, the value of ECR is calculated

10 based on the current construction in the rule. So,

11 the wall thickness is the thinned wall thickness. And

12 it's considering double-sided oxidation.

13 So, as I said, we conducted four tests at

14 Studsvik, and there's a table here which presents some

15 basic features of each test. And I'll go right into

16 comparing the results of these tests with the ones

17 from Argonne.

18 So, on this figure we have the values of

19 the Studsvik bend tests, and a couple of recent pre20 hydrided tests plotted with the values for as21 fabricated cladding that I presented earlier.

22 VICE CHAIR ARMIJO: Michelle, could you

23 just back up a little bit to that picture where the

24 balloon region -- 

25 MS. FLANAGAN: Yes.
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1 VICE CHAIR ARMIJO: Now, in the bend tests

2 did all of these fail in the balloon region?

3 MS. FLANAGAN: Yes. In the Studsvik tests

4 they all failed in the center of the rupture opening.

5 VICE CHAIR ARMIJO: Okay. But not during

6 the quench.

7 MS. FLANAGAN: Correct, there was no --

8 they were in tact following quench.

9 So, again, with the Studsvik results and

10 the pre-hydrided results we continue to see that the

11 increasing oxidation leads to a decrease in bending

12 moment demonstrating that limiting oxidation in the

13 balloon region is appropriate. The balloon region

14 should have an oxidation limit applied.

15 The values of bending moment for

16 irradiated fuel were shown to be reduced relative to

17 the as-fabricated values. And recent re-hydrided data

18 show that the bending moment of pre-hydrided material

19 also is reduced from that of as-fabricated cladding

20 for the same oxidation level.

21 And then what we found was that applying

22 the proposed hydrogen-dependent oxidation limit in the

23 balloon preserves favorable mechanical properties.

24 And to say that, I'll point out that this material

25 that was tested at Studsvik under the new criteria
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1 would be subjected to an oxidation limit of 12

2 percent. Given that it had 200 weight ppm, it would

3 be limited in oxidation to 12 percent, which is a

4 value around -- in between these points, which would

5 preserve a bending moment around between 8 and 9

6 newton-meters. And we see that for 17 percent as7 fabricated cladding we have less than that. So, in

8 other words, we're saying that the irradiated

9 materials preserved properties are greater than that

10 of the as-fabricated cladding at 17 percent. And we

11 saw the same general trends when we examined failure

12 energy. 

13 So, there is a couple of research program

14 conclusions that I want to make, or reiterate. All of

15 our samples survived quench with some margin of

16 mechanical properties. The values of bending moment

17 and failure energy were shown to decrease with

18 increasing oxidation even through a wide range of

19 ballooning strains. Even though very high values of

20 hydrogen content were observed within the balloon

21 region, no matter where the failure was observed the

22 residual bending moment remained a function of

23 oxidation.

24 Also, the value of bending moment and

25 failure energy reveal a hydrogen effect on the
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1 mechanical behavior in the balloon region that should

2 be accounted for. And when the new proposed hydrogen3 based criteria is applied in the balloon region, the

4 mechanical properties in this region are maintained to

5 at least that of fresh cladding.

6 So, I want to address these research

7 program conclusions within a regulatory context in

8 three aspects. First, in the Staff's position for the

9 current rule, or for the revision of the rule, these

10 research results have been used to support using a

11 time and temperature limit based on ring-compression

12 test data to limit oxidation in the entire region --

13 entire fuel rod, including the balloon region with the

14 provisions outlined in the current regulations, which

15 use the average wall thickness and double-sided

16 oxidation.

17 And then going forward in the future, the

18 research conclusions didn't reveal any reason that

19 materials that may be developed in the future that may

20 have better embrittlement properties, that those

21 shouldn't also apply in the balloon region. 

22 So, we anticipate that in the future ring23 compression test program and the regulatory guides

24 that were developed can be used to characterize new

25 cladding alloys, and current alloys at lower oxidation
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1 temperatures. And that the results from those can

2 also be applied in the balloon region, so there

3 wouldn't be a need to go through a four-point bend

4 test program, or an integral LOCA program. There was

5 nothing in our research results that suggested that

6 that would be necessary. 

7 VICE CHAIR ARMIJO: Provided that the

8 ring-compression test on the unballooned materials

9 hydrided, or pre-hydrided were adequate, the results

10 which demonstrate ductility.

11 MS. FLANAGAN: Correct. 

12 VICE CHAIR ARMIJO: I got you.

13 MS. FLANAGAN: Yes. Well, we're

14 suggesting that if the ring-compression tests show

15 improved behavior that can be assumed for the balloon

16 region, as well. 

17 And the last sort of regulatory

18 consideration for our research program results is to

19 comment on alternative performance metrics for the

20 ballooned and ruptured region of the fuel rod. So,

21 there have been longstanding discussions of

22 alternative metrics for fuel rod performance under

23 LOCA conditions within the international community.

24 And our position now is that these approaches really

25 rely on detailed knowledge of LOCA loads and complex
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1 experimental and modeling research programs. And the

2 state-of-the-art today doesn't support a regulatory

3 position based on those proposals in the near-term. 

4 So, at this point pursuing more complex performance

5 metrics for the ballooned and ruptured region isn't

6 recommended.

7 So, I started earlier in this presentation

8 with a quote from RIL-0801. So, given that we've

9 learned a little bit more, and we have some results

10 for the ballooned region, it's appropriate to revisit

11 the conclusions of RIL-0801 and update them to the

12 extent that we can. So, the language and the wording

13 may not be specific, but what I really want to say

14 with this slide is that we intend to revisit RIL-0801

15 and integrate the conclusions of our current program

16 so that that document reflects our current approach to

17 the rulemaking. And that will be something that

18 you'll see in a final form when the rule package is

19 complete. But it will be something along the lines of

20 reiterating a conclusion from this Technical Report,

21 very simply saying that this is our position on the

22 balloon.

23 So, the conclusions of my presentation

24 today are that an integral LOCA research program has

25 generated new data and understanding of mechanical
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1 behavior of ballooned and ruptured fuel rods. These

2 results indicate that limiting oxidation in the

3 balloon region continues to be appropriate. The

4 results also indicate that applying hydrogen-based

5 embrittlement limit in the balloon preserves

6 mechanical behavior to that of as-fabricated rods at

7 17 percent.

8 A Technical Basis Document has been

9 written to supplement the treatment of the balloon

10 within the proposed rulemaking, and updates to RIL11 0801 have been proposed which incorporate the findings

12 of the recent research. And that is my last slide.

13 VICE CHAIR ARMIJO: Okay. I've got a

14 couple of questions, then I'll -- I'm a little

15 confused in that the balloon region appears to be the

16 most fragile part of the fuel rod. And, yet, when you

17 do these experiments on unirradiated and irradiated

18 cladding that region does not fracture during the

19 quench. So, why wouldn't it be reasonable to conclude

20 that the nonballooned region which can have the same

21 amount of hydrogen would be -- should be of concern?

22 Why shouldn't all the focus be on the ballooned region

23 since that's the most fragile part of the fuel rod?

24 And I think there have been other

25 experiments where people have again demonstrated that
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1 the balloon region does not fracture during these

2 quenches, so that's something to think about. I've

3 been thinking about it since our last Subcommittee

4 meeting. I just haven't got a good answer, except that

5 a lot of -- we know a lot more about the metallurgy of

6 the cladding, and we've concentrated a lot on the

7 undeformed materials in a variety of ways trying to

8 demonstrate ductility by the ring-compression test.

9 But then when you have the highly deformed already

10 ruptured balloon region that you accept on the basis

11 of strength, not necessarily ductility, and my

12 question is if the balloon region is okay and measured

13 on the basis of some sort of a strength or energy14 absorption criterion why do we worry about the

15 undeformed region? That's where I'm at, so I'll just

16 let it sit for a while, because I don't have an answer

17 yet, but you may want to comment.

18 MS. FLANAGAN: Well, we got into this a

19 little bit at the Subcommittee. Effectively, there

20 are many LOCA analyses that are limited by the balloon

21 region, so there are many times in which you're right

22 that that location limits the operation and what's

23 possible in ECCS performance.

24 VICE CHAIR ARMIJO: But if we have a LOCA

25 event where you'd get no ballooning, then I would
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1 argue that yes, now you've got to look at the -- 

2 MS. FLANAGAN: Right. And that's the

3 thing, is that in cases where you're not experiencing

4 ballooning and rupture, it's appropriate to apply an

5 oxidation criteria. We know and have seen that the

6 higher the oxidation is, you can get into unacceptable

7 consequences, so there should be some oxidation limit

8 that applies.

9 VICE CHAIR ARMIJO: That would be pretty

10 low temperature if -- to avoid ballooning, you have to

11 stay below what, your 800, something like that,

12 Centigrade?

13 MS. FLANAGAN: Yes, ballooning and rupture

14 happens at a very low temperature.

15 VICE CHAIR ARMIJO: So -- 

16 MS. FLANAGAN: Well, it depends on the

17 pressure -- the differential pressures. It depends on

18 the LOCA scenario that you're dealing with.

19 VICE CHAIR ARMIJO: Okay.

20 MS. FLANAGAN: Yes, around there.

21 VICE CHAIR ARMIJO: All right. Well, I've

22 got to keep thinking about it. Any other -- 

23 MEMBER SHACK: Well, I thought one of the

24 things that we discussed at the meeting was that

25 wasn't always true that the balloon region was the
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1 limiting region, because you've got cooling. You

2 could actually get less oxidation there. And, in fact,

3 the critical region could be somewhere else, so it

4 really -- it was very analysis-dependent. And you

5 couldn't come to the sort of what would seem like the

6 intuitive conclusion that the balloon region really is

7 the -- 

8 VICE CHAIR ARMIJO: The most damaged.

9 MEMBER SHACK: The most damaged.

10 VICE CHAIR ARMIJO: Appears to be the most

11 damaged, and the question is, is that generally true

12 or not?

13 MEMBER SHACK: That didn't seem -- yes,

14 that was the -- I thought the conclusion we came to at

15 the Subcommittee, at least the input from the people

16 who did the LOCA analyses said that that wasn't always

17 the case.

18 MEMBER CORRADINI: It wasn't universally

19 true. That's what I remember was said.

20 MEMBER POWERS: Let me understand one

21 item. You made the point several times in the

22 presentation that all your samples survived the

23 quench, but that quench was a simulation of the quench

24 for ECCS operation, or just a simple -- 

25 MS. FLANAGAN: Not really.
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1 MEMBER POWERS: -- cool down?

2 MS. FLANAGAN: In these tests there was no

3 constraint on the cladding. It was able to freely

4 expand. So, during the quench process you're going to

5 induce thermal expansion which would apply additional

6 loading. 

7 I pointed out that all the samples

8 survived quench because there's something reassuring

9 about that. There's something that is satisfying with

10 the fact that we opened up the test train and it

11 wasn't shattered. There are significant loads in

12 quench, but they were not all simulated in these

13 single rod tests. So, that's where the mechanical

14 testing comes in.

15 MEMBER POWERS: Were any of them -- 

16 MS. FLANAGAN: What is left over after the

17 quench? How much margin to failure do we have? So,

18 that's what the mechanical test prior to quench is

19 really examining.

20 VICE CHAIR ARMIJO: But there's the

21 Japanese testing where they do apply a load during the

22 quench.

23 MS. FLANAGAN: Right.

24 VICE CHAIR ARMIJO: And they find similar25 MEMBER SHACK: But I think Dr. Powers was
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1 sort of wondering whether the quench itself was, in

2 fact, conservative or unconservative compared to what

3 you would expect to find in an actual event. How did

4 you do the quench in the test?

5 MS. FLANAGAN: Temperature-wise, it was

6 the same temperature scenario that was established as

7 a conservative bounding, a large break LOCA scenario

8 that had been used for the Argonne tests. So, we

9 could talk about whether it's -- the temperature

10 scenario is conservative, but the fact that it doesn't

11 include constraint would then -- 

12 MEMBER POWERS: Because I don't understand

13 how the temperature profile would, in fact -- I don't

14 know what conservative means exactly here. Maybe you

15 can explain that. But it seems to me that I'm

16 injecting an ECCS system into it that I go through a

17 temperature scenario at least locally that would be

18 challenging to reproduce in any way in a furnace.

19 MS. FLANAGAN: The temperature scenario

20 would be difficult to -- the local temperature

21 scenario would be difficult to simulate? I don't

22 know. I mean, it's the same waterfront that's creeping

23 off the surface of the cladding, so it is heated by

24 external lamps. But the actual measurement of the

25 temperature -- 
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1 MEMBER POWERS: The only way you -- in a

2 furnace test you can make a step change in the heat

3 flux, but in a quench flux you have a step change in

4 both heat flux and temperature. Those two are very

5 different circumstances.

6 MS. FLANAGAN: Yes, I guess I can't answer

7 your question other than to say that the thermocouple

8 measured a transient and that was what it was

9 calibrated to. And the heating is going to just do

10 whatever it takes, apply whatever power is necessary

11 to maintain that control thermocouple. So, you're

12 right in that sense it might be -- I don't know, my

13 instinct still says that if the actual front is

14 creeping up the cladding that that local temperature

15 gradient and that difference between just above and

16 just below would still be quite representative.

17 MEMBER CORRADINI: All right. I guess, I

18 think all he's asking -- maybe I'm misinterpreting

19 Dana's point, but I think he's asking what's the

20 structural boundary -- what's the -- how are you

21 holding in that boundary condition and how are you

22 cooling in that boundary condition, and how close is

23 it to what you expect?

24 MEMBER POWERS: I mean, those are

25 legitimate questions, but what I know is that when you
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1 subject any material to a step change in heat flux you

2 get a different response than you get when you do both

3 a step change in heat flux and a step change in

4 temperature. The latter is nearly always much more

5 damaging for material.

6 MEMBER CORRADINI: But they're getting

7 both in the simulated case.

8 MEMBER POWERS: No, here they only get a

9 step change in heat flux.

10 MEMBER CORRADINI: Well, no -- 

11 VICE CHAIR ARMIJO: Michelle, how did you

12 do the quench -- 

13 (Simultaneous speech.)

14 MEMBER CORRADINI: -- wouldn't progress up

15 the rod.

16 VICE CHAIR ARMIJO: In these experiments,

17 how did you actually do the quench? Was it with -- 

18 MEMBER CORRADINI: And the heat flux does

19 play -- 

20 MS. FLANAGAN: No, it was with water.

21 Water came in. It was preheated water, so it came in

22 as steam initially.

23 VICE CHAIR ARMIJO: Okay. 

24 MS. FLANAGAN: And then -- yes, a reflood

25 tank was initiated, so there was a waterfront. I can
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1 show you that illustration.

2 MEMBER CORRADINI: Well, I guess I

3 misunderstood Dana's point then, because they get a

4 quench front, and the quench front, assuming they get

5 the right quench front rate, you're going to get this

6 enormous change in temperature along the rod.

7 MS. FLANAGAN: I should say that also the

8 power to the furnace was turned off at the second that

9 the quench was initiated, so whatever heat is there is

10 from the rods inertial heat.

11 MEMBER CORRADINI: It's stored energy.

12 MS. FLANAGAN: Right. So, this -- at this

13 time here, this isn't very illustrative, but this is

14 the quench front reaching the top of the furnace.

15 VICE CHAIR ARMIJO: It's a pretty dramatic

16 thermal shock, but it didn't have the loading that you

17 necessarily would have in a fuel assembly and

18 everything else. But it's comforting to know it

19 doesn't shatter.

20 MS. FLANAGAN: Yes.

21 VICE CHAIR ARMIJO: But it doesn't say

22 anything about the mechanical conditions in an

23 assembly.

24 MS. FLANAGAN: Yes.

25 VICE CHAIR ARMIJO: But it's good to have
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1 that it didn't shatter. We'd have a different

2 meeting.

3 MEMBER CORRADINI: So, you're only taking

4 qualitative, warm feeling out of that. That's the way

5 I interpreted -- you kept on saying that. But I only

6 took it -- 

7 MS. FLANAGAN: The observation -- 

8 MEMBER CORRADINI: -- as a qualitative,

9 warm feeling.

10 MS. FLANAGAN: Yes. The observation that

11 that all samples survived quench is just that,

12 qualitative, warm feeling.

13 VICE CHAIR ARMIJO: But then the other

14 issue was when the ring-compression test -- all our

15 focus is on ductility, measuring the strain, very

16 small strain. In the three-point bend test our focus

17 or acceptance is absorbed energy to fracture, or some

18 strength measurement, but not a strain measurement.

19 And if both are equivalent, why wouldn't we do a

20 simple mechanical strength thing on the ring21 compression test and find that acceptable, just to be

22 consistent from the balloon region to the undeformed

23 region?

24 MEMBER CORRADINI: Can I ask a slightly

25 different question since we're -- 
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1 VICE CHAIR ARMIJO: Okay.

2 MEMBER CORRADINI: So, you don't have to

3 go back to the figure, but the figure where you

4 basically had the bending moment and you had the

5 various temperatures and such, I guess I take -- I was

6 taking -- I was feeling good about it because the

7 qualitative shape on how it changes with hydrogen

8 content, or oxidation content was giving me

9 confidence, and only the Studsvik's test where I

10 actually had more of what I'll call a complete

11 integral test and the overlay gave me the quantitative

12 confidence. Right?

13 MS. FLANAGAN: The Argonne tests were

14 complete integral in the sense that they are single

15 rod and they were brought through the whole

16 temperature. They just didn't have any fuel in them,

17 but they had simulated fuel.

18 MEMBER CORRADINI: Right. But if I go

19 through the Studsvik, your overlay -- it's not that

20 graph. It's one of these graphs.

21 MS. FLANAGAN: This one?

22 MEMBER CORRADINI: Thank you, that one.

23 That in the Studsvik test it was essentially a fuel

24 rod.

25 MS. FLANAGAN: Yes.
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1 MEMBER CORRADINI: Okay. So, I was looking

2 at the shape all being identically the same. I wasn't

3 hoping that they all had to lie on the same line.

4 MS. FLANAGAN: Right. In fact, we expect

5 them -- 

6 MEMBER CORRADINI: That's what I guess I'm

7 trying to get at.

8 MS. FLANAGAN: Yes, we expect them to lie

9 on different lines -- 

10 MEMBER CORRADINI: Right.

11 MS. FLANAGAN: -- as a function of a

12 hydrogen effect.

13 MEMBER CORRADINI: Right.

14 MS. FLANAGAN: So, if there was no

15 hydrogen effect but only oxidation effect, we would

16 have seen all of these points on the same line. And

17 it would just show that the more oxidation you have,

18 the less mechanical behavior you have. And in this

19 case, the fact that they're on different lines is

20 where we came to the conclusion that there is an

21 impact of the hydrogen in the balloon region that

22 degrades mechanical properties.

23 MEMBER CORRADINI: Okay.

24 VICE CHAIR ARMIJO: But it's still

25 adequate. That's what you're concluding, it's still
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1 -- what would your acceptance limit be if you were

2 accepting on the basis of bending moment? Do you have

3 a number, an idea there?

4 MEMBER CORRADINI: I remember I was asking

5 her that at the Subcommittee meeting, and she had a

6 great answer at the moment. I don't remember what it

7 was.

8 VICE CHAIR ARMIJO: I don't remember the

9 answer. Maybe Michelle can -- 

10 MS. FLANAGAN: I mean, we could say that

11 in this scenario what we're saying is the values that

12 we're observing at 17 percent are what we want to

13 maintain. So, you could say -- I really don't want to

14 go back -- 

15 MEMBER SHACK: Why you want to say -- 

16 (Laughter.)

17 MS. FLANAGAN: You know, a lot of the

18 discussion here is really not new. I mean, the fact

19 that the balloon region has been its own beast has

20 been true since 1973. So, we're not trying to get --

21 we're really just trying to assure that what we're

22 doing is appropriate, that we're not missing something

23 in the balloon region, and that we continue to have an

24 understanding of the effects of hydrogen, the effects

25 of burnup, and the effects of oxidation. So, that's
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1 where we're -- that's our objective with this.

2 VICE CHAIR ARMIJO: Okay.

3 MS. FLANAGAN: And some of the things that

4 we're dealing with have been there since this

5 rulemaking was first initiated in the `70s.

6 VICE CHAIR ARMIJO: Michelle, could you go

7 back to your Slide 20? 

8 MS. FLANAGAN: Yes.

9 VICE CHAIR ARMIJO: Would you explain

10 those two data points, the brown that's at zero

11 maximum energy, and the red data point?

12 MS. FLANAGAN: Yes. So, these are pre13 hydrided samples, so particularly the brown one had a

14 hydrogen content of almost 700 weight ppm. And when

15 the sample was brought through a LOCA transient, and

16 then tested in four-point bending, the measured

17 failure energy was very low.

18 VICE CHAIR ARMIJO: Okay. So, it just

19 went up to the elastic range, and broke. There was no

20 area under the curve or something.

21 MS. FLANAGAN: Yes. And I don't think this

22 value is zero, actually. I have to have the table with

23 me -- 

24 VICE CHAIR ARMIJO: Pretty close.

25 MS. FLANAGAN: -- but it's very close to
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1 zero. 

2 VICE CHAIR ARMIJO: Okay. But the

3 irradiated high-burnup ZIRLO was still the order of a

4 unit of .5 to 1 or something on your scale.

5 MS. FLANAGAN: Yes.

6 VICE CHAIR ARMIJO: And those were about

7 200 ppm hydrogen.

8 MS. FLANAGAN: Yes.

9 VICE CHAIR ARMIJO: Okay. I understand the

10 chart. Thanks.

11 All right. Any other questions?

12 MEMBER POWERS: One question, somewhat

13 afield, but one that gets asked to me frequently, and

14 I don't know that you can best -- but I continue to

15 see things coming out of France worrying about

16 collapse of fuel fines into the ballooned region, and

17 it's effect on the long-term coolability. Are you in

18 your program looking at that, or is that on the to-do

19 list, or something like that?

20 MS. FLANAGAN: Relocation is definitely an

21 element of what research is investigating, what the

22 Office of Research is investigating. It's not

23 reflected in this report, and it's not part of the

24 mechanical behavior; however, it is a subject that we

25 are -- 
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1 MEMBER POWERS: Thinking about doing

2 something with.

3 MS. FLANAGAN: Yes.

4 MEMBER POWERS: Come tell us when you've

5 got something to tell us.

6 MS. FLANAGAN: Yes. We certainly will.

7 VICE CHAIR ARMIJO: Okay. If no other

8 questions, I guess we can turn it over to EPRI.

9 (Off the record comments.)

10 MR. YUEH: Good morning. My name is Ken

11 Yueh. I'm Project Manager with Electric Power

12 Research Institute. I just have very brief comments,

13 all of our feedback to the mechanical evaluation of

14 the ballooned and ruptured region.

15 The industry in the past has proposed to

16 use some similar to disposition to whole rod. That's

17 a big area and, therefore, we're fully supportive of

18 the research conducted by the NRC. 

19 I do want to make a comment what was

20 discussed a little bit earlier about the forces that

21 are not known, the fuel is expected to experience post

22 LOCA. People are looking at that. The Japanese

23 working with the Strand system that much about the

24 requirement would expect from real fuel geometry in

25 terms of these strains that you would experience. And
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1 others have done the quench test where they have

2 oxidized fuel clad within a grid, and then they quench

3 the grid. Okay? The fuel rod -- the fuel tube stayed

4 in tact, so it's I think something definable. And I

5 want to say this because the industry is interested in

6 looking at an alternative to the ring-compression

7 test. 

8 As the Vice Chairman alluded earlier, the

9 balloon region is the weakest spot, and the rest of

10 the clad is based on some other test data, has shown

11 at least equal strength compared to the balloon

12 region.

13 What I'm going to present is data

14 generated by both Argonne National Lab and the

15 Japanese, and the results they reported I think are

16 consistent with what NRC just generated. And that the

17 quench survivability, people agree with that.

18 VICE CHAIR ARMIJO: Ken, could you speak

19 up a little bit louder? It's very hard for us to --

20 at least for me to hear.

21 MR. YUEH: Okay. Then the mechanical

22 strength, the degradation of mechanical strength, at

23 least some of the test data is showing there is some

24 dependence initially, but that dependence decreases

25 with both load and ECR. But a lot of the efforts by
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1 other international groups, they're more interested in

2 defining a way to disposition the whole rod, and not

3 necessarily using ductility as a means to demonstrate

4 compliance with coolability.

5 I showed these two slides at the

6 Subcommittee meeting. It is a plot of I think LOCA

7 integral test as part of 1/T, which is high

8 temperature -- shown in this dashed line 1,200 degrees

9 Celsius and the time of oxidation. What this chart is

10 showing, the red, the samples have failed during

11 quench. So there's a lot of space between the 17

12 percent limit and 1,200 degrees in the sample that

13 failed still particular margin.

14 And then on the right-hand side where we

15 show a closer plot as 1/T showing the samples that

16 survived the impact test that absorbed .3 joules of

17 energy. And within this plot shows different

18 populations of different hydrogen concentrations, so

19 you have hydrogen -- this is the hydrogen pickup that

20 joined the LOCA oxidation, so this was not pre21 hydrided. So, above and below the burst you have two

22 minutes of a lot of hydrogen. So, we group that into

23 three different groups, less than 300 ppm, 300-600,

24 and greater than 600. The high samples with hydrogen

25 reached almost 2000 ppm. 
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1 Now, the data is uniformly mixed so there

2 does not appear to be any trend in terms of energy

3 absorption capability as a function of hydrogen

4 pickup.

5 MEMBER SHACK: But that doesn't include

6 any -- I mean, there was no pre-hydriding in this --

7 MR. YUEH: In the next slide I will show

8 some of the Japanese results. And we discussed that

9 at the last meeting about the Japanese test, whether

10 it's a go/no-go test. But they actually did record

11 the load from the quench.

12 This shows the sum of the Japanese test

13 results. This dashed line here is irradiated

14 Zircaloy-4 but hydrogen pre-charged. There's a lot of

15 hydrogen there. In that test, they restrained the

16 system. Post-LOCA when -- during the flooding phase,

17 they restrained the sample to maximum load of 540

18 newtons on the sample. Now, this is generated based

19 on the 540 newtons. This is where below the line the

20 sample survived, above the line the sample failed. 

21 I want to add, I have a paper here I did

22 not show. I just took this chart directly from the

23 paper, from their presentation. I do have a paper here

24 that shows the line -- if the load is increased, the

25 line moves down a little bit. As the line moves down
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1 a little bit, the slope decreases. So, if the system

2 is fully restrained, the sample is allowed to go to

3 the maximum stress, there's almost no hydrogen4 dependence. 

5 VICE CHAIR ARMIJO: Well, Ken, you've got

6 an awful lot of data there, and -- 

7 MR. YUEH: Yes, I won't go -- 

8 VICE CHAIR ARMIJO: All of the arguments

9 of -- 

10 MR. YUEH: So, this is based on non11 irradiated Zircaloy-4 that's been precharged.

12 VICE CHAIR ARMIJO: Okay.

13 MR. YUEH: All right. This is the train

14 there.

15 VICE CHAIR ARMIJO: And that's from the

16 Japanese test setup.

17 MR. YUEH: That's the Japanese test.

18 VICE CHAIR ARMIJO: Okay.

19 MR. YUEH: Now, the other data point boxes

20 are high-burnup multiple alloys. I think they had MDA,

21 ZIRLO, and MFI-1. I'm not sure what it is, multiple

22 alloys. So, the open boxes are the samples that

23 survived the test. So, initially they targeted 540

24 newtons, but some of the samples did not reach -- the

25 stress did not reach that high, so the load was never
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1 reached. Shown on some of them, two of the samples

2 that one with ON, these were not restrained. The ends

3 were loose. The other ones were restrained, and then

4 this one, the actual stress that's given here is less

5 than 400 newtons. This one is 350. Some of the other

6 ones they actually recorded the maximum load on the

7 sample.

8 VICE CHAIR ARMIJO: Okay. I'm still

9 catching up. On the data points labeled ZR-2, ZRT-1.

10 MR. YUEH: These are different -- 

11 VICE CHAIR ARMIJO: Are those irradiated?

12 MR. YUEH: These are all irradiated.

13 VICE CHAIR ARMIJO: Irradiated.

14 MR. YUEH: Box is all irradiated.

15 VICE CHAIR ARMIJO: How much hydrogen did

16 they have in -- 

17 MR. YUEH: It's plotted as function of

18 hydrogen -- 

19 VICE CHAIR ARMIJO: Okay. There is

20 hydrogen going up. Okay. You're all irradiated, and

21 they all survived.

22 MR. YUEH: And the burnup was on the order

23 of 70. It's a little bit less than above this scatter.

24 It's pretty high burnup. 

25 Okay. One sample survived, and one sample
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1 failed, but reached 38 percent ECR. And their

2 conclusion is the factor bunch and it's now reduced

3 significantly by high-burnup and use of new alloys.

4 And they do acknowledge that with non-irradiated

5 material, there's an initial decrease in the fracture.

6 But that decrease as the stress, as amount of load,

7 restraint you apply to it is increased that dependence

8 almost disappears. 

9 VICE CHAIR ARMIJO: Okay. Well, it seems

10 somewhere along the line that these data sets, the

11 ring-compression data where we're measuring very small

12 amounts of residual ductility, and these mechanical

13 property tests, all the variables are addressed.

14 Somewhere somebody should try and put this together

15 and make a meaningful explanation of what is really

16 going on, and what's -- the implication is you have a

17 lot of margin.

18 MR. YUEH: Yes.

19 VICE CHAIR ARMIJO: That's what you're

20 saying.

21 MR. YUEH: Yes, and I did -- 

22 VICE CHAIR ARMIJO: The ring-compression

23 test, you're measuring very small amounts of strain,

24 so it's a very difficult test to do. Makes you worry

25 whether you have enough margin or not. 
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1 MR. YUEH: Well, I do want to show that --

2 your point here. This is the -- what's proposed for

3 the ring-compression test, and if we reduce this line,

4 let's say NRC has some threshold here, if we move the

5 line down to that threshold, it is a tremendous amount

6 of margin still compared to the ring-compression test.

7 So, that's a point I want to make. And support one of

8 the recommendations we have on my next slide.

9 VICE CHAIR ARMIJO: Okay. Keep going.

10 MEMBER SHACK: Is the 15 percent the

11 actual Japanese regulatory limit, or is that

12 somebody's proposal?

13 MR. YUEH: That's their regulatory limit.

14 MEMBER SHACK: Okay.

15 VICE CHAIR ARMIJO: Okay, keep going.

16 MR. YUEH: This is what I -- 

17 MEMBER CORRADINI: Can you go back? We're

18 debating privately, so maybe we'll just make it

19 public. So, I'm trying to understand what -- so, Sam

20 basically said it best, which is you've got this data

21 over here, and somehow I'm looking for some sort of

22 interpretation.

23 VICE CHAIR ARMIJO: Yes.

24 MEMBER CORRADINI: So, if I'm

25 understanding, since this is like the third time I've
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1 heard this in various forms, are you basically saying

2 it's the pre-hydriding experimental technique that is

3 biasing the data that we're seeing? I'm trying to

4 understand what -- and maybe you said it, and I just

5 don't get it.

6 MR. YUEH: It's a different metric. One

7 is based on ductility, the other one is based on

8 strength.

9 MS. FLANAGAN: Can I interject something?

10 It's also looking at margin from a different

11 perspective. We look at quench when we do a

12 mechanical test afterwards, and we see what mechanical

13 properties are left. And another approach would be to

14 crank up oxidation until quench alone fractures the

15 material. And then there's an additional load on

16 these tests. So, it's like a different perspective on

17 what margin means. It's in terms of oxidation, or it's

18 in terms of mechanical behavior. Does that make

19 sense? How far away am I? How come -- 

20 VICE CHAIR ARMIJO: I've still got to

21 think of how this all comes together, because as

22 metallurgists, we love ductility. I mean, how can you

23 argue, if you have a ductile material, that's great.

24 But it's very hard to measure when you're down in

25 these -- in the dirt of the measurement of around 1
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1 percent, you start getting nervous that you're kidding

2 yourself. But these measurements on irradiated

3 cladding under constraint with high hydrogen

4 concentrations indicate you've got a lot of mechanical

5 margin in some way.

6 MR. YUEH: Yes. 

7 VICE CHAIR ARMIJO: And I'd like to see

8 how this all -- it must all come together, because

9 it's the same -- and I don't understand it yet, but --

10 MR. YUEH: Yes, it's approaching from

11 different methods, to find a way to reconcile the

12 difference, or try to make sense might be a little bit

13 difficult. But I -- one thing I forgot to state

14 earlier is the 540 newtons used in the Japanese test,

15 people actually have done real test, and the actual

16 measure load is on the order of 170-200 newtons. And

17 they want to be conservative. They're stuck with

18 earlier evaluation, which shows 540 newtons, so it's

19 even another conservatism. 

20 VICE CHAIR ARMIJO: And all of these are

21 just pure axial loads, no bending loads or anything

22 like that?

23 MR. YUEH: Axial -- 

24 VICE CHAIR ARMIJO: Okay. I've got to read

25 that paper again. Those are the Nagase papers?
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1 MR. YUEH: Yes, I have a copy of it here.

2 VICE CHAIR ARMIJO: Yes, I've got one.

3 Thank you.

4 MR. YUEH: You've got one. Okay.

5 MEMBER BROWN: For the really simple6 minded, me, I listened to both sides, and I'm just

7 having a hard time similar to your comment; how do you

8 bring these together? I mean, I look at this and it

9 says based on your 540 newtons, and I may state this

10 incorrectly, so fix me. Is that you've got all these

11 hydrogen -- you've got all these hydrogen

12 concentration samples and you loaded them to 540

13 newtons, and didn't -- 

14 MR. YUEH: What they have done is, it's a

15 LOCA integral test.

16 (Simultaneous speech.)

17 MEMBER BROWN: -- where they failed at the

18 upper and lower points?

19 MR. YUEH: That's right. It's fixed in

20 place, and during the quench the amount of load

21 applied -- as the sample -- 

22 (Simultaneous speech.)

23 MR. YUEH: The sample shrinks due to

24 cooling.

25 MEMBER BROWN: Okay. 
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1 MR. YUEH: So, it's restrained, and the

2 maximum load that the test parameter allows is 540

3 newtons. So, if the load is actually -- if actually

4 the sample shrinks -- 

5 MEMBER BROWN: Pull that apart.

6 MR. YUEH: Yes, if it shrinks more, then

7 the system relax a little bit, but keep the load at

8 540 newtons.

9 MEMBER BROWN: And they did not break.

10 MR. YUEH: They did not break, no. 

11 MEMBER SHACK: Okay. But then you come to

12 Dr. Powers' questions sort of in spades, is that you

13 really have to be sure that your test is prototypical

14 and limiting, and that you've counted for all the

15 loads that you might want to account for; whereas,

16 with the ductility you, in fact, have margin to

17 account for -- should that 540 having a plus or minus

18 uncertainty on it, that takes into account everything

19 that might not be prototypical about your test.

20 MEMBER BROWN: Well, but his comment was

21 that the maximum loads they saw were substantially

22 less than the 540 -- 

23 MEMBER SHACK: It's not guarantee didn't

24 do a LOCA.

25 MR. YUEH: It's not refuel, it's obviously
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1 the -- 

2 MEMBER BROWN: Well, neither of them -- 

3 (Simultaneous speech.)

4 MEMBER BROWN: Right, neither one of them,

5 so -- 

6 MEMBER CORRADINI: But on the other hand,

7 though, the argument would be -- at least to answer

8 Dana's point, the argument would be with when you're

9 doing it based on I'll just say the dark red line

10 versus the dashed line, you're basing it on a sense

11 that since it's not prototypic, you have margin,

12 unmeasured but knowable -- but margin there.

13 MEMBER BROWN: Right.

14 VICE CHAIR ARMIJO: And keep in mind,

15 we're still looking for coolable geometry, and all of

16 this stuff is saying this stuff isn't going to fall

17 apart. You're going to still have something that looks

18 like a fuel assembly when you're finished. And the

19 question, to me, is what's the best way to measure it

20 that gives you the most confidence, and is most

21 reliable. And I -- the only thing makes me

22 uncomfortable about the ring-compression test is we're

23 measuring numbers down in the dirt, and that's hard to

24 measure. And I just worry that I don't -- haven't

25 seen the -- 
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1 MEMBER SHACK: It is clearly giving you

2 more conservative results.

3 VICE CHAIR ARMIJO: Well, yes, it's

4 conservative, but it may be -- 

5 MEMBER SHACK: I mean, if you have margin,

6 Sam, that -- 

7 VICE CHAIR ARMIJO: No, but it may be

8 unrealistic. You might be getting stuff that's

9 measured zero that has -- in fact, it's perfectly good

10 material for the application. 

11 MEMBER POWERS: Not after this, it's not

12 perfect.

13 (Laughter.)

14 VICE CHAIR ARMIJO: No, I mean adequate,

15 adequate. Okay, Ken, go ahead.

16 MR. YUEH: So, to summarize, I made this

17 point at the last meeting, because the draft rule is

18 about meeting ductility, and balloon region at least

19 in the range we have a lot of hydrogen there is no

20 ductility, so there's a conflict. And because the

21 rule is the law, that we recommend that the ductility

22 requirements be placed in the regulatory guides.

23 And then the second point is what Dr.

24 Armijo -- I think his similar thought about if it's

25 acceptable to the balloon region, why would the rest
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1 of the rod be concerned? And our position is because

2 it appears that the clad does not decay from --

3 degrade at the same rate as ductility in terms of

4 strength. You know, there's probably no margin if we

5 use the strength-based metric. I think that's all I

6 have. Thank you.

7 VICE CHAIR ARMIJO: Okay. Any comments,

8 questions?

9 (No response.)

10 VICE CHAIR ARMIJO: With that, I'd like to

11 thank the Staff and EPRI for -- I guess I could ask if

12 there's any questions from the people in the room.

13 (No response.)

14 VICE CHAIR ARMIJO: Okay. So, thank you

15 very much. We're ahead of schedule.

16 CHAIRMAN ABDEL-KHALIK: Thank you. We are

17 45 minutes ahead of schedule.

18 VICE CHAIR ARMIJO: Thank you very much.

19 MR. YUEH: Thanks so much.

20 CHAIRMAN ABDEL-KHALIK: We're off the

21 record.

22 VICE CHAIR ARMIJO: Okay, thank you.

23 (Whereupon, the proceedings went off the

24 record at 12:00 p.m., and went back on the record at

25 1:43 p.m.)
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1 A-F-T-E-R-N-O-O-N S-E-S-S-I-O-N

2 (1:43 p.m.)

3 CHAIRMAN ABDEL-KHALIK: We are back in

4 session. 

5 At this time, we will move to Item

6 Number 4 on the agenda, Technical Basis and Rulemaking

7 Language Associated with Low-Level Waste Disposal

8 Site-Specific Analysis. And Dr. Ryan will lead us

9 through the discussion.

10 MEMBER RYAN: Thank you, Mr. Chairman.

11 This is one of two Subcommittee meetings that we will

12 have -- one now, one in August I guess is the rough

13 schedule -- and then we are planning for a letter in

14 September aggregating our information gathering from

15 the previous Subcommittee, the two upcoming

16 Subcommittees, and the full Committee input.

17 So I would appreciate it if members would

18 advise me of any opinions or thoughts or any kind of

19 input they want to provide from this meeting in

20 preparation for the next Subcommittee meeting and then

21 the followup letter in September with the full

22 Committee. 

23 So with that introduction, I will turn to

24 Andrew Carrera from FSME, who is going to open the

25 session for us. Andrew?
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1 MR. CARRERA: Yes. Thank you, Dr. Ryan.

2 Good afternoon. My name is Andrew Carrera, and I'm

3 the Project Manager for the Part 61 site-specific

4 analysis rulemaking. And before I begin, I would like

5 to thank the members and staff of the ACRS for giving

6 us the opportunity to present our rulemaking and

7 technical basis to you today.

8 First, I will briefly go over the reason

9 why we are conducting this particular rulemaking and

10 then go over the proposed changes that the staff has

11 made to the proposed rule language. And then, Dave

12 will follow me with his presentation on the technical

13 basis of this rulemaking, and then I will come back

14 and briefly go over the stakeholders' comments that we

15 received on the preliminary proposed rule language.

16 Next slide, please.

17 Now, as you may be aware, when the

18 original Part 61 regulations were developed, there was

19 a set of conditions that were analyzed by the staff at

20 that time. These include certain existing defined

21 volumes and concentrations of radioactive waste.

22 However, those conditions are changing, and low-level

23 waste disposal facilities are facing -- are currently

24 faced with disposing of waste types and quantities

25 that were not considered at that time.
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1 And one significant parameter that was

2 considered but ultimately did not make its way into

3 the Part 61 was uranium, and particularly large

4 quantities of depleted uranium. And I'll refer to it

5 as DU from now on.

6 The quantities of DU that were considered

7 during the original Part 61 development were much,

8 much smaller than the challenges that we are facing

9 with today, and that is one of the cornerstone why we

10 are conducting this particular rulemaking.

11 MEMBER RYAN: Andrew, just for my own

12 benefit, if you could explain a little bit -- one

13 million metric tons sounds like a lot, but most wastes

14 are measured in volume. I would really like to know

15 what the volume of this million metric tons is. Maybe

16 not right this second, but if we could hear it in

17 those terms, that might be a helpful comparative for

18 us.

19 The other part of that is a lot of DU I

20 know is metal, and I would be curious as to how much

21 of that million metric tons was metal versus some

22 other form that might be more mobile in the

23 environment.

24 MR. ESH: The quantity -- this is Dave

25 Esh. The quantity is fairly large, too. I mean, at
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1 a metric ton, you're talking about a thousand

2 kilograms per metric ton, and the density that is in

3 powdered form, you're talking about a powder packed

4 inside a barrel is packed inside a facility. 

5 My guess is it probably works out to be

6 somewhere around four to five thousand kilograms per

7 cubic meter, so -- density. So you can -- if you

8 wanted to convert this to cubic meters, it's quite a

9 few cubic meters. Just a rough guess.

10 MEMBER RYAN: Okay. That's fine. That's

11 helpful. Thank you.

12 MEMBER BLEY: And one cubic meter is

13 probably a couple of barrels? I'm just --

14 MR. ESH: Yes. A barrel I think I

15 estimated before would be maybe like a half a metric

16 ton, something like that.

17 MEMBER BLEY: And so a couple of

18 barrels --

19 MR. ESH: Yes.

20 MEMBER BLEY: Per ton.

21 MR. ESH: I'm getting older, though, and

22 my memory is, you know, so --

23 MEMBER BLEY: It will get worse.

24 (Laughter.)

25 MR. ESH: We could give you a better
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1 number, but for context that's --

2 MEMBER BLEY: All I wanted was context.

3 MEMBER RYAN: People sometimes work in

4 volume and weight, and it would be helpful to have an

5 answer to that question.

6 MR. ESH: Well, the material, as it's

7 generated, is usually in some fluoride form, but we

8 don't think the fluoride forms are at all acceptable

9 for disposal. So the concept is that you will convert

10 the fluoride forms probably to an oxide, which is more

11 stable for disposal, so your question about what the

12 form of it is, we expect most of this material should

13 be oxide.

14 MEMBER RYAN: And there are some -- there

15 is some DU metal that is disposed as well.

16 MR. ESH: There is DU metal that is

17 disposed, too.

18 MEMBER RYAN: A component of --

19 MR. ESH: When you're dealing with metals,

20 if it's a big block or ingot of metal, that's one

21 thing, but if you -- say you are dealing with uranium

22 shavings, and you start worrying about pyroforicity --

23 MEMBER RYAN: Yes.

24 MR. ESH: -- and other things, too, so --

25 MEMBER RYAN: A lot of it these days is
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1 intact pieces and parts.

2 MR. ESH: Yes.

3 MEMBER RYAN: All right. Thank you.

4 Sorry for the interruption, Andrew.

5 MR. CARRERA: Thank you, Dr. Ryan. And

6 there would also be significant changes in the ways in

7 which the nuclear power industry managed their waste,

8 and the emergence of a concept known as blending. And

9 blending is when you take Class B and Class C waste

10 and blend them with Class A waste to lower the waste

11 classification, and then dispose them as Class A

12 waste. And blended waste were also not considered in

13 the original development of Part 61 regulations.

14 MEMBER BLEY: I don't deal with this stuff

15 every day. Remind me what the classes are, and what

16 classes do you --

17 MR. CARRERA: DU, by default, is a Class A

18 waste. And there are three classes of waste of A, B,

19 and C, and their designation is based on how --

20 MR. ESH: The three waste classifications

21 -- A, B, and C. A is -- in concept is supposed to

22 decay to levels that don't pose a risk to an intruder

23 at 100 years. So after 100 years somebody could dig

24 into it and not have an exposure above what is

25 intended. 
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1 Class C waste is intended to meet that

2 general concept at 500 years, so Class C waste, for

3 Class C waste there is a requirement that you either

4 have to have an intruder barrier that lasts for 500

5 years, or you have to dispose of it at least five

6 meters deep. And B is in between. It's -- has waste

7 stability requirements associated with it, I believe,

8 of 300 years.

9 But the general framework for low-level

10 waste was we'll take -- mainly dealing with shorter

11 lived waste, things that are dominated by the cobalt12 60s and the strontium-90s and cesium-137s of the

13 world. And we'll make a framework that we can put

14 those into, so that as they decay over time we manage

15 the risk through our regulatory framework and our

16 technical requirement.

17 For depleted uranium, we had this other

18 box in the regulation. We'll talk about it as

19 61.55(a)(6) is how we'll refer to it, which when they

20 wrote the regulation they basically said anything that

21 doesn't fall into the other boxes is Class A by

22 default. 

23 Well, uranium didn't fall into the other

24 boxes, so it's Class A. But a legal interpretation of

25 the regulation is that it's Class A. Technically,
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1 whether that's right or not, I would say probably not.

2 But legally that's the decision.

3 MEMBER SIEBER: And the activity actually

4 increases over time.

5 MR. ESH: Yes. So there is a --

6 MEMBER SIEBER: Doubles.

7 MR. ESH: -- there is two tables in the

8 regulations that define the waste classification, and

9 Table 1 has the long-lived isotopes. And to be

10 Class A, you have to be basically one-tenth of the

11 concentrations that are provided in Table 1. To be

12 Class C, you have to be at or below the concentrations

13 in Table 1.

14 So there are long-lived isotopes that are

15 disposed of as low-level waste, but the analysis was

16 designed to limit the concentrations that you would

17 have of the long-lived waste that goes into the

18 system.

19 MEMBER BLEY: And all three classes are

20 low-level waste.

21 MR. ESH: All three classes are low-level

22 waste. That's correct.

23 MR. CARRERA: Thank you. Next slide,

24 please.

25 MEMBER RYAN: Sorry, Andrew. We've got a
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1 comment.

2 MR. McKINNEY: Chris McKinney, Performance

3 Assessment Branch for NRC. I just want to clarify

4 that we actually have a fourth class of low-level

5 waste, which is greater than Class C waste, which is

6 a federal responsibility and isn't disposed of

7 currently under the commercial -- at commercial sites.

8 But there is --

9 MEMBER RYAN: It is disposed at DOE

10 facilities.

11 MR. McKINNEY: Right. But there is DOE12 like material that is disposed of. It is, again, not

13 -- they don't use our classification system.

14 MEMBER RYAN: Okay.

15 MR. McKINNEY: But there is a fourth class

16 that we don't discuss much, but it is part of low17 level waste, so low-level waste is A, B, C, and

18 greater than Class C.

19 MEMBER RYAN: I think one member's benefit

20 -- and it's a point that I think about a lot -- is

21 that none of this is quantity driven. It's all

22 concentration driven. So a very small amount of

23 greater than Class C waste might be something you

24 could put in your pocket, but it's still greater than

25 Class C and unacceptable for disposal as low-level
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1 waste, and vice versa.

2 VICE CHAIRMAN ARMIJO: What is the nuclear

3 medicine waste? Is that in this category of low-level

4 waste that comes out of --

5 MR. CARRERA: Yes, it's -- it depends on

6 where it -- where the low-level waste

7 classification --

8 MEMBER BLEY: It could be any of the

9 three?

10 MR. ESH: It could be, yes.

11 MEMBER RYAN: I guess it's -- I think it's

12 fair to say -- and correct me if I'm wrong, Andrew or

13 David -- but most radionuclides used in medicine are,

14 by their nature and requirement, short-lived. Some of

15 the generators, like the molybdenum generators from

16 which tech-99 comes from, is a longer-lived

17 radionuclide. 

18 So it's not all just the short-lived

19 stuff, but the quantity -- whether it's 2- to 300

20 curies nationwide of that stuff is relatively small

21 compared to, say, what the nuclear power industry

22 generates. So it's not a huge burden --

23 VICE CHAIRMAN ARMIJO: So it's not much --

24 MEMBER RYAN: -- to deal with.

25 VICE CHAIRMAN ARMIJO: -- of a contributor
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1 to this issue.

2 MR. ESH: No. All of the what I would

3 call in our context very short-lived -- you know, we

4 have -- in low-level waste, our framework has a 100-

5 year institutional control period. So anything five

6 years and below, it's really hard to show up. So it

7 basically all decays in place. So all of the very

8 short isotopes associated with medical waste would

9 fall into that description.

10 MR. CARRERA: Okay. I'll just continue.

11 The Commission is aware of these issues and has been

12 working with the staff to address them. And as a

13 result, and in a staff requirement memorandum, SRM, to

14 SECY-08-01447, the Commission directed the staff to

15 proceed forward with a limited scope rulemaking to

16 Part 61 to require low-level waste disposal facilities

17 to conduct site-specific analysis prior to the

18 disposal of significant quantities of depleted

19 uranium, and to develop technical guidance for

20 conducting these analyses.

21 And in a subsequent SRM, the Commission

22 directed staff to incorporate blended waste into the

23 existing rulemaking for depleted uranium. So the

24 site-specific analysis rulemaking we are talking about

25 today covers both of these emerging issues.
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1 Next slide, please.

2 And with the Commission direction in mind,

3 the staff developed a technical basis document to

4 support this rulemaking. A multi-disciplinary

5 rulemaking team was formed, and the rulemaking process

6 started in October 2010. The staff developed the

7 objectives and purpose of the proposed rule, and that

8 is to specify site-specific analysis requirements for

9 low-level waste disposal facilities to demonstrate

10 compliance with the performance objectives in Part 61.

11 And these site-specific analyses are

12 listed here -- performance assessments, which would be

13 included in Section 61.41; intruder assessments, which

14 would be included in Section 61.42; and long-term

15 analysis, which would be included in a newly proposed

16 section, Section 61.13(e); and number 4, updated

17 analysis. 

18 I have Section 61.13(e) on the screen, but

19 actually it's 61.28 and 61.52, which is correct on

20 your handouts.

21 And these analyses would enhance the safe

22 disposal of low-level waste and would also identify

23 any additional measures that would be prudent to

24 implement. And I will go into greater details of each

25 of these analysis requirements in a moment.
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1 VICE CHAIRMAN ARMIJO: So you are going to

2 cover for each of those --

3 MR. CARRERA: Yes, sir.

4 VICE CHAIRMAN ARMIJO: -- including the

5 intruder stuff, because I'd like to look -- understand

6 more about that particular --

7 MR. CARRERA: Yes.

8 VICE CHAIRMAN ARMIJO: Requirement.

9 MR. CARRERA: And we have talked to the

10 technical basis of why the staff chose to include

11 intruder assessment and the requirement in its

12 technical talk.

13 Next slide, please.

14 And the staff also proposed additional

15 amendments to the current Part 61 regulations to

16 facilitate the implementation and to better align the

17 requirements for the current health and safety

18 standards. 

19 In addition, when it developed Part 61

20 regulation, the NRC considers potential doses to an

21 offsite member of the public and an inadvertent

22 intruder based on certain assumptions regarding the

23 type of waste that was likely to be found in a

24 commercial low-level waste disposal facility.

25 As mentioned before, large quantities of
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1 depleted uranium and blended waste were not included

2 in the technical basis, because they were not

3 envisioned to be a major candidate for disposal at the

4 Part 61 facility.

5 Recently, these waste streams have become

6 candidates for disposal, which necessitates this

7 particular rulemaking. And the staff was concerned

8 that there may be other previously unanalyzed waste

9 streams that will also become candidates for disposal

10 at the Part 61 disposal facilities in the future, and

11 would, therefore, require other rulemaking like this.

12 So, and the staff considered a number of

13 options in development of this proposed rule, and the

14 staff decided that an amendment that requires site15 specific analysis for all types of waste would be the

16 most comprehensive approach.

17 MEMBER BLEY: I'm trying to come to grips

18 with something I suspect is a legal statement rather

19 than a technical one, but I'm not positive. You said

20 the reason you need the rulemaking is because you

21 hadn't envisioned that you would be in a Part 61 waste

22 facility, but do use in some kinds of waste facilities

23 already, right? It's just that they weren't called

24 Part 61, because Part 61 didn't deal with DU. Am I

25 right on that?
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1 MR. ESH: Yes. I think the answer --

2 MEMBER BLEY: There's a lot of it around,

3 I think, right?

4 MR. ESH: I think the answer is that it is

5 in various types of facilities, and there -- as some

6 of our licensees like to remind us, there are

7 exemption criteria that allow you to determine certain

8 material as exempt, too. And you can dispose of DU

9 counterweights in facilities right now, because

10 they're exempt. So --

11 VICE CHAIRMAN ARMIJO: Is that because

12 they're metal, metal form, or if --

13 MR. ESH: That's part of the issue here is

14 I think, you know, we'll talk about quantities and

15 concentrations and those sorts of things, but you also

16 have to really think about form. There is a big

17 difference between when you are disposing of something

18 with a very high surface area to volume ratio, like a

19 powder, and you are disposing of a big block of metal.

20 Those pose --

21 VICE CHAIRMAN ARMIJO: Yes.

22 MR. ESH: -- two different dispersibility

23 risks to people or the environment, but we're dealing

24 with a lot more of the latter, not the former.

25 VICE CHAIRMAN ARMIJO: Okay. But I wanted
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1 to get at the issue. Is there a preferred depleted

2 uranium? Does the staff identify a preferred form

3 like metallic big box? Would it be an ideal form?

4 MR. ESH: Well, I'll walk through --

5 VICE CHAIRMAN ARMIJO: Okay.

6 MR. ESH: -- the technical aspects of the

7 problem, and then we can talk about that at the end.

8 My background before coming to NRC was in waste form

9 development, and I think when you are going out to

10 longer times you much more need to focus on the

11 material science aspects of the problem and less on

12 some of the other things that are more common in

13 traditional facilities.

14 So you have to think really hard about

15 what's the form that I'm going to dispose of. We are

16 generally in the position that we don't demand or

17 dictate a particular form, but we try to give

18 information to say, "If you want to develop a form,

19 here are the steps you should go through to determine

20 whether that is appropriate or not." 

21 So it's up to a licensee to propose, okay,

22 I want to make a glass ceramic with the depleted

23 uranium in it, or I want to make concrete with

24 depleted uranium in it, or I just want to put it in in

25 the powdered form and try to demonstrate what the
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1 risks are associated with that.

2 VICE CHAIRMAN ARMIJO: But right now, if

3 somebody had a lot of metallic uranium, they could go

4 the exemption route.

5 MR. ESH: Well, if it's counterweight.

6 VICE CHAIRMAN ARMIJO: If it's

7 counterweight.

8 MR. ESH: If it's a specific -- if it's

9 boxed out of the specific type of material. But no,

10 otherwise, it would be a waste stream just like --

11 just like some other form, some other physical form.

12 MEMBER BLEY: Just one last question from

13 me before you go on and give us the details. Does NRC

14 regulate chemical toxicity or just radiotoxicity?

15 MR. ESH: Just radiological toxicity.

16 MEMBER BLEY: Go ahead.

17 MR. ESH: EPA regulates chemical toxicity.

18 MEMBER RYAN: Sam, I would also offer to

19 you to think about it's not only the waste form, it's

20 the waste package, the disposal technology, the cover

21 technology, an entire system working together to

22 confine and contain whatever the material is, not just

23 the waste form. Although the waste form is an

24 important one, I think it's helpful to think about it

25 as a system rather than as one element by itself.
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1 MR. ESH: It's very analogous to a reactor

2 system that has multiple safety components --

3 MEMBER RYAN: Sure.

4 MR. ESH: -- or defense in depth and all

5 things that you try to put in place to mitigate the

6 risk. The waste disposal systems have the same sort

7 of features. They're different and they're much more

8 passive and much less active, so --

9 MR. CARRERA: Next slide, please.

10 Now I'll go into the details of the site11 specific analysis requirements, and let's start with

12 the performance assessment in Section 61.41.

13 Part 61 currently requires licensees to

14 prepare an analysis to demonstrate that the low-level

15 waste disposal facility meets the requirement in

16 Section 61.41, and that is to ensure the protection of

17 the general population from releases of radioactivity.

18 This analysis is currently called a

19 technical analysis, instead of a performance

20 assessment, and does not contain a period of

21 performance associated with the analysis.

22 The staff proposed revision to this

23 section to include specifically the use of the term

24 "performance assessment," and also the use of the TEDE

25 dose methodology, so that the Part 61 regulation will
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1 be consistent with the radiation protection standard

2 in Part 20.

3 The proposed rule would also specify a

4 newly defined period of performance of 20,000 years

5 for the performance assessment.

6 Now, Dave will talk later in his technical

7 presentation of the staff's basis for recommending the

8 20,000 years period of performance.

9 Next slide, please.

10 And intruder assessment -- again, Part 61

11 currently does not require a licensee to perform an

12 intruder dose assessment to demonstrate compliance

13 with Section 61.42, which is for the protection of an

14 inadvertent intruder.

15 VICE CHAIRMAN ARMIJO: Why do you have to

16 protect -- set these broad, broad rules to protect

17 isolated intruders that are really a hypothetical

18 assumption? Where do you get the obligation to

19 protect this person?

20 MR. ESH: That's a good question. When

21 Part 61 was developed, they -- we aren't adding this

22 performance objective.

23 VICE CHAIRMAN ARMIJO: Well, I understand

24 it's there.

25 MR. ESH: The performance objective is
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1 there, and it's partly there because when the

2 regulation was developed it was around the time where

3 some national events, such as Love Canal, happened,

4 and there was this concept that, while we can provide

5 some controls and restrictions to try to prevent

6 access or use of the site in the future, that you

7 can't all together prevent that over long periods of

8 time, because you are relying on things like records

9 and markers and institutional knowledge.

10 The NRC's policy and approach is not to

11 have active maintenance or active control of the

12 facility past the institutional control period. So

13 when you go out over time, they thought, well, we need

14 something to evaluate what happens if somebody

15 accesses the site and inadvertently disturbs the site

16 or contacts some of the material. That's where the

17 performance objective was derived from.

18 It's not necessarily done in other fields,

19 such as in the disposal of industrial metals, but it

20 is done in the nuclear field pretty commonly

21 throughout the world, not just in the U.S. but

22 internationally it's done.

23 VICE CHAIRMAN ARMIJO: And this

24 inadvertent intruder opens up this disposal site, and

25 basically lives there continuously, and you are
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1 supposed to protect them?

2 MR. ESH: Possibly, yes. The waste

3 classification tables -- the waste classification

4 tables were developed assuming that somebody -- they

5 looked at different scenarios, okay. 

6 So they looked at scenarios of, well, what

7 happens if somebody uses the site and digs into it,

8 but the material is distinguishable from the -- they

9 know they have waste, okay? We dug somewhere we

10 shouldn't have dug, and we accessed material in the

11 facility. That's called intruder discovery scenario.

12 But then, they also analyzed, what happens

13 if the material isn't distinguishable from the

14 material that they are digging into? What are the

15 risks they are going to be exposed to? That was

16 broken out into an acute intruder scenario and a

17 chronic intruder scenario, so somebody that builds a

18 house on the site, puts in a foundation, the guy that

19 builds the house is the acute intruder, the person

20 that lives in the house after the house is built is

21 the chronic intruder.

22 VICE CHAIRMAN ARMIJO: And this applies

23 out to 20,000 years for --

24 MR. ESH: Well, in the original analysis,

25 it was done to -- it didn't have a timeframe
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1 associated with it. So it was done and the waste

2 classification tables were derived from it using an

3 inverse calculation. And I'll talk about it whenever

4 we get to my presentation.

5 Right now, we're saying that NRC initially

6 took the effort of deciding, well, we want to protect

7 this intruder. It's a performance objective that was

8 developed. There's two ways of going about that. NRC

9 can either do the calculations and develop tables,

10 which is the approach they took, or they could say,

11 okay, each licensee do this calculation for your

12 individual site, and you develop the concentrations

13 that you can take.

14 They envisioned that there were going to

15 be lots of low-level waste disposal facilities, so

16 they opted to take the route of NRC will develop the

17 tables and develop the concentrations, and those will

18 apply to all facilities.

19 So that's kind of the history of where it

20 came from, and we are within the scope of -- we are in

21 a limited scope rulemaking. So to do something like

22 to remove a performance objective would be maybe

23 pushing the limits of what is expected in this limited

24 scope rulemaking.

25 VICE CHAIRMAN ARMIJO: I think you should
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1 try.

2 MR. ESH: Yes.

3 VICE CHAIRMAN ARMIJO: I think to set

4 these requirements for this hypothetical intruder

5 20,000 years from now, and protect him and, you know,

6 the cost and the effort, is it really worth this?

7 MEMBER RYAN: Sam, and one other further

8 protection that David hasn't touched on yet for the

9 longer term is that back when the rule was first

10 written there really weren't substantial institutional

11 control funds at these sites. 

12 And now there are in the tens of millions

13 of dollars held, you know, specifically for the

14 purpose of long-term monitoring and maintenance that

15 were not there when the rule was written. So that's

16 an added feature to current practice that is not

17 reflected in the current rule.

18 And, you know, from my experience in

19 monitoring and maintaining a site, $10 million is

20 plenty of money to go a long time.

21 VICE CHAIRMAN ARMIJO: Well, it just seems

22 like it's almost from the same category as general --

23 protection of the general population, which is the

24 proper role. There's no question about that. But

25 this isolated, hypothetical, individual, thousands of
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1 years into the future -- how can that make any sense?

2 MR. ESH: Let's defer maybe additional

3 discussion until I -- because I have some slides to

4 talk about in detail, and then we can revisit it.

5 VICE CHAIRMAN ARMIJO: Sure.

6 MR. ESH: All right.

7 VICE CHAIRMAN ARMIJO: I mean, it's a

8 policy issue that's not -- that's not currently up for

9 grabs is what you're saying.

10 MR. ESH: You're certainly free to make

11 that comment.

12 (Laughter.)

13 VICE CHAIRMAN ARMIJO: Believe me, I will.

14 MR. CAMPER: Let me add a comment to this,

15 if I might, please. Larry Camper, Director of

16 Division of Waste Management, Environmental

17 Protection. Around your question, I would point out

18 that we have the assignment from the Commission -- we

19 have three assignments from the Commission today

20 around Part 61. 

21 One was to conduct a limited rulemaking,

22 which is what we're talking about today, which is to

23 require the site-specific performance assessment

24 focused around large quantities of depleted uranium.

25 Now, one interesting thing that has
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1 occurred is that the working group has decided to make

2 it apply to all radionuclides, not just large

3 quantities of depleted uranium. That's because they

4 heard that during public comment gathering, but,

5 still, we would argue that that is consistent with the

6 limited scope rulemaking.

7 The second assignment that we have is to

8 risk-inform the waste classification scheme and look

9 carefully at what is depleted uranium in that context.

10 And then, the third thing is to look at

11 Part 61 more comprehensively. And what we decided to

12 do was to go out and solicit public input, and so

13 forth, and come back to the Commission with a

14 recommendation in December. But the kinds of things

15 that you're talking about -- this notion of, do we

16 need to have an inadvertent intruder -- would be in

17 that bigger policy look at Part 61. But we understand

18 your point.

19 VICE CHAIRMAN ARMIJO: That's still within

20 the scope of the direction you've been given.

21 That's --

22 MR. CAMPER: No, it's not.

23 VICE CHAIRMAN ARMIJO: It's not.

24 MR. CAMPER: It's not.

25 MEMBER RYAN: I guess I want to make a
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1 point on that, Sam, that it seems like it's backwards

2 from that standpoint. If you're going to change the

3 overarching policy, you probably ought to do that

4 before you redo the regulation.

5 VICE CHAIRMAN ARMIJO: Okay.

6 MEMBER RYAN: I think that -- I think

7 that's something for the Committee to think about is,

8 are we out of order in terms of what it's best to do

9 first.

10 VICE CHAIRMAN ARMIJO: Yes, priority.

11 MEMBER RYAN: Thank you, Larry.

12 MR. CARRERA: Yes. I think we discussed

13 intruder assessment enough. Let's move on to the

14 long-term analysis.

15 Staff has determined that it would be

16 prudent to require additional long-term analysis to

17 ensure that waste streams significantly different from

18 those considered in Part 61's technical basis can be

19 disposed of while still meeting the performance

20 objectives in Part 61.

21 And the proposed long-term analysis, which

22 would be added to a new section -- Section 61.13(e) --

23 will consider the uncertainties associated with the

24 disposal of long-lived waste streams. This analysis

25 is needed to determine whether limitation on the
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1 disposal of some long-lived waste streams at certain

2 sites may be needed to ensure for the safe disposal.

3 This analysis will require consideration

4 of peak annual dose that would occur 20,000 years or

5 more after site closure. No dose limit would apply to

6 the results of the analysis, but the analysis would

7 need to be included as an indication of a long-term

8 performance of the disposal facility.

9 VICE CHAIRMAN ARMIJO: Do you think it's

10 actually practical that anybody could actually show

11 you that they can guarantee that this facility would

12 be functional for 20,000 years without any

13 supervision, with it just abandoned in place?

14 MR. ESH: I think you have to understand

15 the process of performance assessment, what it is

16 intended to do, and what it can do, and what it can't

17 do. It is intended to incorporate all significant

18 uncertainties and reflect those in the output that you

19 are generating to evaluate against a criteria. 

20 And in some cases those uncertainties can

21 be large and diverse. There are different things you

22 can do to try to mitigate them, including engineering

23 of your facility. But then you are talking about

24 passive performance of engineering over very long

25 periods of time. I think --
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1 VICE CHAIRMAN ARMIJO: That's my point.

2 That was the Yucca Mountain philosophy. And to

3 demonstrate that this was possible, you could easily

4 challenge every one of those demonstrations because of

5 the uncertainties, and you wound up redesigning and

6 overdesigning and overdesigning the overdesign,

7 because --

8 MEMBER RYAN: Excuse me, Sam. I'm sorry

9 to interrupt, but the -- I just got a note. The

10 conference line is not open, and there are a number of

11 people on the conference line.

12 Theron, can we open the conference line?

13 Or, Derek, could you check and see if the conference

14 line is open and -- or make it open? Hang on just a

15 second, please.

16 (Pause.)

17 MEMBER RYAN: Okay. I understand the

18 conference line is open. If you could all put your

19 phones on the conference line in listen-only mode,

20 that would be helpful.

21 VICE CHAIRMAN ARMIJO: Okay. Just to --

22 MEMBER RYAN: Thank you. I'm sorry, Sam.

23 Excuse the interruption.

24 VICE CHAIRMAN ARMIJO: Just to go back, it

25 just seems to me that having reviewed -- not as part
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1 of the ACRS, but in the university job -- the Yucca

2 Mountain approach, it really couldn't converge. And

3 one barrier after another didn't resolve -- didn't

4 eliminate the challenges, because we're talking about

5 times that are just so long -- I guess Yucca Mountain

6 is now up to one million years.

7 I just think that these aren't really

8 practical or achievable. So if you write a rule, it

9 should be achievable, and so that somebody who said --

10 does the assessment can demonstrate it either by

11 experience or test or geological history or something

12 that says, "Hey, it's satisfactory."

13 MR. ESH: I would say that, at 20,000

14 years, you are certainly pushing the limits of what

15 you can do with many engineered systems, in a near16 surface environment in particular. But the

17 performance assessment process is about looking at the

18 engineered systems and the site -- the natural site

19 conditions to evaluate how it's going to mitigate the

20 risk from the facility.

21 The questions that you're asking are, what

22 is your obligation as you go out in time to try to

23 generate those impacts? And the answer can be that I

24 don't think I have any obligation beyond a certain

25 point in time, but that -- because of uncertainty,
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1 remember, low-level waste is the first step in the

2 waste management train. 

3 You don't have to dispose of material at

4 low-level waste if you don't know what the impacts are

5 and you think the uncertainties are too large. You

6 can take that material and place it into deeper

7 disposal, similar to what's done with transuranic

8 waste or -- and geologic disposal.

9 The waste management system is designed to

10 manage and mitigate uncertainties. And if you believe

11 the uncertainties associated with an action are too

12 large for near-surface disposal, then maybe you are

13 not putting the material in the right box, is the

14 argument I would say.

15 VICE CHAIRMAN ARMIJO: Well, you know, if

16 the rules are set up that they can easily be

17 challenged, and that you can't dispose of anything

18 without enormous cost, then you haven't done your job.

19 That's -- and that's what I worry, that when I see

20 numbers like this, that you are pushing in the same

21 direction that we got into with Yucca Mountain, and --

22 MR. ESH: I don't think you have an

23 obligation, though, to make the problem easy if in

24 fact it's not easy.

25 VICE CHAIRMAN ARMIJO: I'm not talking
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1 about making anything easy. I'm talking about making

2 it realistic.

3 MR. ESH: But if you don't set the

4 criteria appropriately strictly, then everybody

5 passes. And maybe it --

6 VICE CHAIRMAN ARMIJO: I'm not talking

7 about that.

8 MR. ESH: -- maybe everybody shouldn't

9 pass. I think you have to set the criteria

10 appropriate for the problem, and then you determine

11 who is going to pass and who is going to fail. I

12 would argue that if I take only low concentrations of

13 long-lived waste, or only short-lived waste, whether

14 I set the period of performance at 10,000, 20,000, or

15 100,000 is not an issue at all.

16 I can demonstrate easily with technical

17 analysis that I can limit the risk from that facility.

18 So it's an issue of, when the problem becomes

19 difficult, what should be your criteria for that

20 difficult problem? We are in that box with this

21 rulemaking.

22 VICE CHAIRMAN ARMIJO: Well, I've got to

23 hear a little bit more about the specifics of the

24 particular waste and the particular waste form. But

25 it can't be one size fits all, and that's the
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1 impression I'm getting.

2 MR. ESH: Okay.

3 MEMBER RYAN: Sam, I'm sure -- Sam?

4 VICE CHAIRMAN ARMIJO: Yes.

5 MEMBER RYAN: We'll touch on that today

6 some I'm sure, but maybe that's a topic for our next

7 Subcommittee meeting. Or perhaps we could plan ahead

8 and go into little bit more detail. Would you be okay

9 with both of those solutions?

10 VICE CHAIRMAN ARMIJO: Sure.

11 MEMBER RYAN: And I guess I'm just trying

12 to --

13 VICE CHAIRMAN ARMIJO: I'm trying to

14 understand --

15 MEMBER RYAN: -- help shape it today, so

16 that the next time we come we can have a full

17 discussion on that topic, because I know, David, you

18 have talked at some length about that with the

19 Subcommittee, and it would be helpful to create that

20 opportunity again.

21 VICE CHAIRMAN ARMIJO: You know, I think

22 -- I read some documentation of Department of Energy

23 practices, and they use a term of "reasonableness,"

24 which I think would be nice to hear in NRC stuff, in

25 dealing with these things. And maybe you already feel
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1 you are being reasonable, but I will withhold

2 judgment.

3 MEMBER RYAN: Chris?

4 MR. McKINNEY: On the reasonableness, it's

5 already in our regulations in all of the performance

6 objectives, a reasonable assurance. We have that

7 strewn throughout Part 61 as it is, and we're talking

8 mostly about the changes here.

9 Maybe for our next meeting we will focus

10 definitely on how the structure of the rule came up in

11 some other ones to put a little bit more on the

12 context of the --

13 MEMBER RYAN: Anything specifically that

14 addresses Dr. Armijo's concern and question, that

15 would be helpful.

16 MR. McKINNEY: Right.

17 MEMBER RYAN: Thank you. Gentlemen?

18 MR. CARRERA: Next slide, please.

19 Updated site-specific analysis

20 requirement. Currently, Section 61.28 and 61.52,

21 which applies to disposal facility license closure

22 program, do not have requirements for updated site23 specific analysis. 

24 The staff proposed revision to this

25 section, to include requirement for this updated
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1 analysis, as part of the application process to amend

2 the license for closure. And updated analysis

3 requirement is needed to provide greater assurance of

4 compliance with the performance objectives in Part 61.

5 MEMBER RYAN: Correct me if I'm wrong, but

6 I think every site that exists today has some period,

7 like 100 years or so, of committed institutional

8 control and monitoring to help further the data

9 analysis for that endpoint. I think that's a very

10 important point, that there is a current funded

11 capability at every one of these sites to do

12 monitoring and maintenance and geohydrologic study and

13 radiological analysis of samples, and all of that, for

14 100 years post-closure.

15 So just wanted to add that detail for the

16 members' benefit.

17 MR. CARRERA: Thank you, Dr. Ryan.

18 And, finally, the staff also proposed

19 additional amendments to the Part 61 regulation, such

20 as adding new definitions or concepts as part of the

21 program to facilitate the implementations of the site22 specific analysis.

23 And that concludes my presentation on the

24 preliminary proposed rule, and we can -- Dave will

25 talk about the technical basis reporting of this
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1 rulemaking.

2 MR. ESH: Okay. A little bit of

3 background about myself. I have worked in performance

4 assessment for about 16 years on low-level waste,

5 complex decommissioning sites, high-level waste, and

6 waste incidental to reprocessing. 

7 Prior to joining NRC, I worked at Argonne

8 National Lab on treatment of sodium-bonded spent

9 nuclear fuel and development of waste forms associated

10 with that process. I'm going to talk to you today

11 about the two key technical areas that we were faced

12 with in this rulemaking and try to shed some light on

13 where we ended up, where we did, and why.

14 The two main topics I'm going to cover are

15 the intruder assessment and the period of performance.

16 We also are in the process of developing a guidance

17 document that goes along with the rule, that will be

18 issued in parallel with the rule, that outlines the

19 staff's position on what analyses to do and how to do

20 it and things to consider -- a generic technical

21 guidance document on low-level waste covering the

22 rulemaking topics that we have here, and some

23 additional areas where we felt additional guidance was

24 needed.

25 Both of these areas I would argue are
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1 important technical areas, given the Commission

2 direction. As Andrew indicated, the Commission

3 direction to us is to develop technical requirements

4 necessary for the disposal of large quantities of

5 depleted uranium and blended waste.

6 As I will talk about later in the

7 presentation, I think the issue is a little more

8 generic than that, even though they highlighted those

9 two types of materials to fit into our low-level waste

10 framework.

11 The technical requirements that are

12 developed do provide a common framework for all

13 licensees to be evaluated against. In low-level waste

14 disposal, right now all of our facilities are located

15 in Agreement States. So the Agreement States develop

16 their regulations and apply it to the disposal of low17 level waste.

18 So in the development of this regulation,

19 we want to ensure that there is common requirements

20 that are applied against all the Agreement States

21 where there is -- when it's needed, when there's

22 important requirements.

23 So the first area we will talk about is an

24 intruder assessment. The intruder assessment has

25 three parts. It has a waste classification and
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1 segregation requirements, intruder barrier

2 requirements, and intruder dose assessment

3 requirement.

4 The intruder assessment -- the first two

5 parts are not new. They're in the existing

6 regulation. Existing regulation has waste

7 classification, segregation requirements, and intruder

8 barrier requirements. As we talked about, there are

9 three classes of waste. There are just different

10 requirements for the different classes of waste.

11 What we have added in this rulemaking is

12 the intruder dose assessment, and that is because the

13 Commission directed us to not alter the waste

14 classification system. So any material that is new,

15 that wasn't analyzed in the EIS when Part 61 was

16 developed, then would be outside of the tables

17 potentially.

18 And the way that we thought, well, in this

19 limited scope rulemaking that we could address that

20 problem would be to have the licensees do an intruder

21 dose assessment. That will capture any new material

22 that is generated.

23 We were also sensitive to the fact, and

24 consistent with the stakeholders that we heard from in

25 the workshops in 2009, maybe in the past we weren't as
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1 smart as anticipating what low-level waste streams

2 were going to look like today. Maybe we're not as

3 smart today as what they are going to look like in the

4 future either.

5 So this approach handles that. It allows

6 it to adjust no matter what the waste that's

7 generated. If you're doing this intruder dose

8 assessment, that is essentially what NRC would do if

9 we were going to revise the tables. We would revise

10 the waste classification tables by doing an intruder

11 dose assessment and calculating the concentration,

12 which would give us a certain limit short --

13 MEMBER BLEY: And, again, I don't want you

14 to answer this now. I just want to ask the question,

15 because I don't -- didn't see where you are going to

16 answer it when I skimmed through your slides. With

17 respect to dose assessment for DU, when you get to the

18 place you are going to talk about that, I would like

19 to understand the kind of scenarios that are involved

20 in getting to the doses that would be applicable here

21 for individuals.

22 MR. ESH: Okay. Under the intruder

23 assessment, the -- and the other part of it, or all of

24 it? Okay.

25 MEMBER BLEY: Specifically, intruder
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1 assessment, but I think it comes up elsewhere, too.

2 So --

3 MR. ESH: Okay. All right. Yes. If I

4 forget, remind me.

5 VICE CHAIRMAN ARMIJO: David, this is one

6 intruder or a large group of intruders?

7 MR. ESH: It is envisioned to be an

8 individual type of -- or, you know, a few people type

9 of scenario. Okay?

10 One thing that I think was misunderstood

11 by some of our stakeholders is the issue of intruder

12 barriers, and they say, "Well, if you're applying this

13 20,000-year requirement to run for your intruder

14 assessment, how are you going to demonstrate an

15 intruder barrier for 20,000 years?"

16 We are not requiring a 20,000-year

17 intruder barrier. The intruder barrier requirements

18 are what they are for the three classes of waste.

19 What we are saying is that if you can put in an

20 intruder barrier, that you can justify its performance

21 over whatever period of time you need it to perform,

22 go right ahead and do that, provide the technical

23 basis for it. But we don't have a requirement for an

24 intruder barrier out to 20,000 years.

25 We have a requirement for meeting the
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1 intruder dose assessment over this 20,000 years. And

2 you can try to mitigate the impacts from that in

3 whatever way you see fit.

4 And as we talked about, the reason for

5 this is this waste classified under 61.55(a)(6) could

6 represent an unanalyzed condition for this performance

7 objective that is in the regulation. So as I talked

8 about previously, the waste classification system was

9 developed by the NRC staff, and it was done with this

10 thought that, "Well, I have two ways to go about this

11 problem. I can let licensees do this calculation or

12 NRC can do the calculation and develop the

13 concentrations that licensees need to meet to meet

14 this requirement."

15 They chose to develop the concentrations

16 and put them in Tables 1 and 2 in addition to the

17 associated requirements in the regulation. And I

18 think that was smart, because, as we have kind of

19 talked about some here, beat around the bush on, you

20 are dealing with future human behavior, and it's very

21 uncertain.

22 So do you want that open to licensee

23 interpretation and, therefore, you are going to have

24 an awful lot of variability about how it's done? Or

25 do you want to have some constraints to it about how
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1 it's done?

2 When NRC did the calculation, that

3 provided some constraints to how it was done. It

4 also, in some cases, did things that I would say

5 aren't risk-informed, because it obligated you to

6 analyze one type of condition. In the case of the

7 development of the classification tables, it was done

8 for a humid site, and that was applied to all sites,

9 then, because all sites are bound to the

10 concentrations in the tables.

11 So if you do allow somebody to do the

12 intruder dose assessment, you have to be careful you

13 don't get into speculation about the scenarios, open

14 speculation about what's a credible scenario. But you

15 also allow for some flexibility of considering actual

16 site conditions.

17 So what is the natural conditions? Is it

18 reasonable to put a house at a certain location?

19 What's the persistent of those natural conditions over

20 time? What is the current land use? How would you

21 interpret the current land use of projecting into

22 future land use? All those things come into play.

23 MEMBER RYAN: David, one element I have

24 asked about before, and I think it's important to get

25 a handle on it in this kind of conceptual development
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1 you are talking about is, when does an inadvertent

2 intruder become an advertent intruder?

3 MR. ESH: Yes. 

4 MEMBER RYAN: Then, you go from not

5 knowing anything to knowing something that you ought

6 to take action on. I think that's left completely

7 unaddressed and needs to be addressed.

8 MR. ESH: Yes. Well, the difficult -- let

9 me step back. The NRC, when they developed the

10 regulation, they said, "We aren't protecting advertent

11 intruders." So somebody that deliberately tries to go

12 into a waste disposal facility, that is beyond what we

13 should be required -- that is beyond what we will

14 require people to protect against.

15 But the inadvertent intruder is somebody

16 who doesn't know the material was there. And whether

17 that's credible or not, you have to really step

18 outside of the box and think about these long

19 timeframes. And I would argue, especially engineers,

20 we are subject to recency bias. So we think about

21 what has happened in our lifetime, in the immediate

22 lifetime, but how much that translates into, what is

23 going to happen in 500 or 1,000 years? I think that

24 is a very uncertain proposition.

25 And so we don't want to get locked around
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1 just because what is happening today makes sense, is

2 that -- it's what is going to make sense over these

3 very long time periods. And I would say, think about

4 what has happened right here at Rockville over the

5 last 250 years. Rockville looked a lot different 250

6 years ago than it does now. 

7 And if you asked somebody 250 years ago

8 whether they would have a 30-story high rise and

9 iPhones and everything else, I don't think they would

10 predict --

11 MEMBER RYAN: You are mixing apples and

12 oranges. You know, the question isn't, what will we

13 have 200 or 500 or 1,000 years from now. The question

14 is, what can we recognize --

15 MR. ESH: Well, if we can --

16 MEMBER RYAN: -- 200 or 500 or 1,000 years

17 from now.

18 MR. ESH: If the waste is recognizable,

19 our guidance is go ahead and take credit that that

20 waste is recognizable. That's more of a science and

21 engineering program -- or problem. But when you're

22 dealing with, what's the likelihood that somebody

23 takes that action, there are lots of examples of

24 people doing unintended things, including right down

25 the road here in Spring Valley where they started
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1 digging up a bunch of mustard gas.

2 Just the other day I was reading --

3 MEMBER RYAN: But they stopped.

4 MR. ESH: But they stopped when they found

5 it.

6 MEMBER RYAN: That's my point.

7 MR. ESH: But --

8 MEMBER RYAN: They became an advertent

9 intruder when they recognized this wasn't what was

10 expected.

11 MR. ESH: Well, they took actions to

12 mitigate the risk.

13 MEMBER RYAN: And the regulation doesn't

14 allow for that opportunity.

15 MR. ESH: They took actions to mitigate

16 the risk, but over very long periods of time, what is

17 your ability to recognize, is the issue. You're

18 dealing with a lot softer problem than an engineering

19 problem when you are talking about future human

20 behavior.

21 MEMBER RYAN: I understand that part, but

22 saying it is intractable and there is nothing we can

23 offer to an inadvertent intruder becoming somehow an

24 advertent intruder is not good either.

25 MR. ESH: Well, I don't know when -- I
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1 don't think the scenarios and the behaviors that are

2 -- that we are putting forth in the current rulemaking

3 are extreme, irrational scenarios and behaviors.

4 MEMBER RYAN: I didn't say they were. I'm

5 just simply saying you have left one aspect completely

6 out.

7 MR. ESH: But I don't know how you credit

8 something to protect health and safety when you don't

9 know it.

10 MEMBER RYAN: "Don't know how" doesn't

11 mean it's not a good idea that you address it.

12 MR. ESH: But how do you credit it?

13 MEMBER RYAN: I don't know. I mean, we'll

14 have to think about that and work on that.

15 MR. ESH: If you have a recommendation of

16 how you credit that, and you tell your stakeholders

17 how you're crediting it, I --

18 MEMBER RYAN: I can give you several that

19 you wouldn't --

20 MR. ESH: -- would be on board with that.

21 MEMBER RYAN: -- like, but I'll work on

22 one you might like.

23 MR. ESH: I mean, I think we have -- you

24 have to really think carefully about these timeframes,

25 and what does your experience and our experience mean
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1 over the timeframes, because --

2 MEMBER RYAN: I agree.

3 MR. ESH: -- because I think there is a

4 big difference when you are thinking 100 or 500 years

5 and low-level waste associated with 100 or 500 years.

6 I think you are on much stronger ground to credit

7 current behaviors, what is the current land use, what

8 is the likelihood of determining whether the material

9 is recognizable.

10 On the hundreds of year timeframe, you are

11 on much stronger footing crediting those things. On

12 the thousands of year timeframe, I think you are on

13 much weaker footing trying to credit those things.

14 VICE CHAIRMAN ARMIJO: So is it your

15 assumption that the governments, society, will be

16 equivalent to today, and will exist and will be

17 functioning, but no more, no wiser, no more capable?

18 Or is your assumption that at 10-, 20,000 years from

19 now, there may not be a United States, there may not

20 be a government, there are not -- we may be wandering

21 around digging holes looking for food?

22 MR. ESH: The original developers of

23 Part 61 envisioned this as an unlikely event, albeit

24 possible. I think that's the language that was used

25 in the regulation. I think we are generally in
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1 agreement with that. 

2 It doesn't require societal failure for

3 these things to occur. It requires you to not have

4 persistent markers, records, government error, all the

5 sorts of things that happen -- I mean, my dissertation

6 was put on electronic media that I can't even read

7 today, and that's not that long ago.

8 So you have -- there's a whole research

9 area in the development of the persistence of records

10 and markers and all that sort of -- it's kind of a

11 softer feel, but I think that is where this comes into

12 play. There is a lot of stakeholders that have that

13 opinion and have that concern, and also, as I

14 indicated, this was derived around a certain time when

15 these sorts of things did happen on a pretty public

16 scale, so --

17 MEMBER RYAN: Did you --

18 MEMBER BLEY: No, no, I was just hoping

19 you could get through more of this before we run of

20 out time, so I can understand it better.

21 (Laughter.)

22 MR. ESH: All right. So the intruder

23 assessment, though, it is a regulatory construct. It

24 is not a calculation of exactly what is going to

25 happen in the future. It is a regulatory construct to
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1 provide some level of protection.

2 You could argue that it is too much

3 protection, it's arbitrary, whatever. That is the

4 construct. It's in the regulation. This is a limited

5 rulemaking. We don't have much ability to eliminate

6 a performance objective in the scope of this

7 rulemaking.

8 MEMBER RYAN: So there's two points here,

9 David. I think everybody appreciates, from your

10 perspective, this is not in the scope of what you are

11 addressing at this point. But I think the Committee

12 is free to think about and discuss and evaluate

13 whether or not something might be recommended by the

14 Committee on the regard of what they think about the

15 intruder scenario --

16 MR. ESH: That's fine. And the

17 Committee --

18 MEMBER RYAN: -- the way it evolves.

19 MR. ESH: Yes. The Committee can

20 certainly recommend that. The intruder assessment is

21 supported by a variety of groups that I have listed

22 here. It's not NRC staff coming up with this idea and

23 methodology. It is used throughout the waste

24 management world, community, as part of their

25 assessments. Not universality -- or not universally,
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1 but it is much more common to see it than not see it.

2 We do evaluate the potential exposure of

3 the intruders after the institutional control period,

4 which is 100 years. A dose limit of 500 millirem TEDE

5 is applied. This is different than the 25 millirem

6 that is applied under 61.41. It is implying an

7 unlikely -- the unlikelihood of the occurrence. You

8 could interpret it that way. And that it is only

9 going to impact a few individuals.

10 So it's not applying the same dose limit

11 as 61.41. If you thought that this was a probability

12 one scenarios, you would have no reason to not set it

13 at 25 rather than 500. But it is an unlikely scenario

14 that has this implied probability reflected in the

15 dose limit that is assigned to it.

16 MEMBER STETKAR: But, Dave, now you are

17 starting to talk about risk assessment. That dose

18 limit is miraculously 20 times higher than the 25

19 millirem.

20 MR. ESH: Yes.

21 MEMBER STETKAR: Where did the factor of

22 20 come from? Is that a surrogate for a five percent

23 probability somehow?

24 MR. ESH: Well, you can interpret it that

25 way, as a five percent probability, but --
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1 MEMBER STETKAR: Do you know the history

2 of it?

3 MR. ESH: The history of it is, at the

4 time, Part 20 had 500 millirem as a public dose limit,

5 and they assigned the same dose limit that was in

6 Part 20 at the time. And the reason -- in the current

7 rulemaking, we are -- we want to stick with the 500,

8 because that is what all the table values were derived

9 for. 

10 So we could -- we are kind of in this --

11 we are kind of in this box of, well, you should assign

12 it to what Part 20 is, which is 100 today, but then it

13 would be inconsistent with the 500 values that are

14 implied by the table value. So we recommend you to

15 stick with the 500, but that's where it came from.

16 It works out to -- I mean, I think it's

17 self-consistent. It's not inconsistent.

18 MEMBER RYAN: It is internally consistent

19 within 61, but it is inconsistent with other parts.

20 MR. ESH: Possibly, yes.

21 MEMBER RYAN: And other environmental

22 regulation parts as well.

23 MR. ESH: The last point here on this

24 slide, we are recommending reasonably foreseeable land

25 use scenarios impacted by the timeframe and the change
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1 in the natural site condition. So maybe your site is

2 very arid today, and you want to dispose of long-lived

3 waste. Over that long period of time, we know some

4 things about climate cycling. There are a lot of

5 climate scientists out there. They argue with each

6 other a lot.

7 But the actual fact that climate changes

8 on a somewhat repeatable pattern has occurred in the

9 past, if your site is going to change significantly as

10 that climate change goes on, I mean, I read a report

11 before that they were saying that some of the real

12 arid parts of Arizona were a lot more like Montana at

13 some points in the past.

14 So, to me, that seems reasonable. If you

15 want to dispose of long-lived waste, you need to think

16 about how your climate and environment are going to

17 change over time. 

18 So that's in general, though, the intruder

19 assessment. It's a very debatable topic, as we have

20 already had. 

21 So one problem that we had from our

22 interactions with our stakeholders is our draft

23 language where in the first bullet here, under number

24 one, we had in the definition, "Assumes that an

25 inadvertent intruder occupies the site."
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1 We think that you don't necessarily have

2 to assume they occupy the site. "Accesses" is

3 probably a better word, and you do -- like I said, you

4 consider the actions of the intruder based on the

5 current land use and the environmental conditions,

6 et cetera.

7 As you go out over longer periods of time,

8 that becomes more uncertainty, and maybe you do have

9 to be more conservative in your scenarios that you

10 select. But that was a point of discussion in the --

11 MEMBER BLEY: Well, I'm a little -- my

12 interpretation of "occupies" in there is that whatever

13 he happens to stir up he lives in day in and day out,

14 not just he wandered into it and wandered out again.

15 So it's not conservative to say "access." That's --

16 MR. ESH: No, it's not conservative to say

17 "access." I think we're saying we should -- it is all

18 right to be less conservative, especially over the few

19 hundred year timeframe, which would make a big

20 difference for blended waste and short-lived waste.

21 It's not going to make a difference at all for longer22 lived waste, but we are arguing that you -- it is okay

23 to consider some of these things over the shorter

24 timeframes.

25 So this language that we'll discuss in the
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1 working group, but we may change it from the original

2 -- what went out and what you saw.

3 So now we are on to the easier topic of

4 the period of performance. We have some very strong

5 opinions on this matter. At the 2009 workshops that

6 we had with a diverse set of stakeholders, they of

7 course couldn't agree on a period of performance, but

8 they could all agree that we should put it in the

9 regulation. So that's what we attempted to do.

10 I think in our meeting with the

11 Subcommittee Mr. Sieber described it well. He said,

12 "This isn't something that is really amenable to

13 technical proof, or something like that, and I think

14 that is a good description. Or technical rigor. It's

15 not amenable to technical rigor. This is a lot more

16 of an outside of the box problem than an inside the

17 box problem.

18 In 2010, the ACRS recommended to us to not

19 put a period of performance in the regulation, which

20 was in direct conflict with what we heard in our

21 workshops. I'm going to try to explain in this

22 presentation why we did what we did and how we think

23 we were trying to be consistent with the previous

24 direction from the ACRS.

25 So the period of performance is one of the
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1 many important elements in the safety evaluation of

2 low-level waste disposal, not the only one. There are

3 a whole bunch of things that go into the safety of

4 low-level waste disposal -- siting requirements,

5 technical analysis requirements, the performance

6 objectives. The period of performance is one thing

7 that comes into play, and it's a pretty important one,

8 or it can be.

9 Different approaches are used within the

10 U.S. and internationally for low-level waste. So, in

11 the U.S., it is undefined right now. That's our

12 policy. U.S. policy, NRC policy, on low-level waste

13 performance assessment, there is no period of

14 performance. Agreement States are free to interpret

15 and develop what they see fit.

16 Internationally, quite different

17 approaches are used to the period of performance for

18 low-level waste. Many of the European countries, for

19 instance, are much more comfortable with long

20 timeframes, and I think that's because they have been

21 around a lot longer.

22 The U.S. is much more uncomfortable with

23 long timeframes. But if you go out and look and see

24 what people use and what they talk about and why they

25 are using it, in many cases they will go out to peak
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1 dose no matter when that happens, and they will do

2 that for industrial metals, too, not just radiological

3 materials. As I said, we have diverse opinions among

4 our stakeholders.

5 When you're talking about concentrated

6 long-lived waste, I think that's where the period of

7 performance comes into play. It doesn't really come

8 into play for many other types of materials.

9 The NRC background on this, it's not a new

10 issue. It has been talked about a lot since 1994.

11 There are a whole bunch of ACNW letters on this, and

12 the ACNW communicated some basic principles that we

13 tried to stay faithful to in this rulemaking, which I

14 will show in the next slide, back in 1997. And that

15 was specifically for low-level waste disposal.

16 We have very little Commission direction

17 on this. We have an SRM in 1996 that they said

18 provided basis for truncating the period of

19 performance at 10,000 years. That's all the

20 communication that we have from the Commission on this

21 topic.

22 During this time -- this timeframe, couple

23 of decade or 15-year timeframe, we had a performance

24 assessment working group that was formed at NRC, and

25 they were looking at this issue and discussed it with
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1 the ACNW a lot and went back and forth.

2 Originally, it was a Branch Technical

3 Position, and then they basically couldn't get through

4 with this period of performance issue at that time,

5 and the report was issued as a NUREG, and the staff

6 recommended 10,000 years at that time with longer term

7 impacts in the site environmental assessment.

8 I think it's important to understand the

9 context of this recommendation. Okay? At that time,

10 they were discussing the performance standards for

11 Yucca Mountain, and Part 60 had a period of

12 performance of 10,000 years in it.

13 Part 63 initially also had a 10,000-year

14 period of performance in it. And the performance

15 assessment working group wanted to stay consistent

16 with what was being done in the high-level waste

17 program.

18 Well, eventually, as probably all of you

19 are aware, with the National Academy of Sciences

20 getting involved and the lawsuits and EPA, that

21 Part 63 got revised and they ended up with a million22 year period of performance or compliance period. It

23 has two phases to it. It has a 10,000-year initial

24 phase and then a higher dose limit for the second

25 phase, but it is a million-year time of compliance, is
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1 I think how they describe it.

2 Not all Agreement States have requirements

3 to do the second part of what was recommended by the

4 performance assessment working group here -- the

5 longer term impacts and the site environmental

6 assessment. So part of what we came up with -- the

7 61.13(e) requirements -- are because of this issue,

8 that the facilities are licensed in Agreement States,

9 and they have different requirements to how they

10 handle -- how they may or may not have to do site

11 environmental assessments.

12 And the one thing that I will point out as

13 we get to a complicated table in the back is this

14 performance assessment working group recommendation

15 was based on, in large part, a consideration of

16 radionuclide travel times. They looked at one type of

17 condition for that analysis -- a humid, shallow site.

18 Our recommendation is based on looking

19 more broadly at the types of facilities you could have

20 throughout the U.S.

21 VICE CHAIRMAN ARMIJO: But you could start

22 off with a very dry site, and for these long periods

23 of time you can't guarantee that a dry site won't

24 become a dry -- a lake. So how do you deal with that?

25 MR. ESH: Well, the performance assessment
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1 has to include the variation in the site environmental

2 conditions over time, which does mean that an arid

3 site could in fact become a more humid site over time.

4 Generally, you switch between, let's say, one box on

5 like a climate classification chart and not multiple

6 boxes. So you don't go from very arid to humid. You

7 will go from semi-humid to humid, or you will go from

8 semi -- or arid to semi-arid type of changes. But

9 they aren't necessarily --

10 MEMBER RYAN: You can go the other way,

11 too. You can --

12 MR. ESH: And then you go back the other

13 way.

14 MEMBER RYAN: Yes.

15 MR. ESH: And then, absolutely, you go

16 back the other way, yes. But it isn't a change across

17 multiple boxes. But the evaluation has to include the

18 changes in those environmental conditions over the

19 assessment.

20 Let's see here. The ACNW principles that

21 were expressed -- and, obviously, you are not bound by

22 the past ramblings of your elder Committee members,

23 but --

24 (Laughter.)

25 -- but we considered them, because that's
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1 what we had, and there is a lot of good information in

2 there. One of the messages that they had was that we

3 should consider the site-specific characteristics, and

4 they said, "Okay. No less than the time for the more

5 mobile radionuclides to produce a peak dose." 

6 Well, that's great. What does that mean?

7 You know, there is a big difference between this --

8 converting this principle to practice. And I think

9 when you convert it to practice, it becomes a bit of

10 a challenge, and I will talk about that on a slide

11 coming up.

12 MEMBER RYAN: David, there is one element

13 of context here that I think is fairly important to

14 grasp. During this time period from -- and this is

15 the late '70s. By the way, this is before my time on

16 the ACNW.

17 (Laughter.)

18 By a lot.

19 (Laughter.)

20 Waste form, waste packaging, and waste

21 processing has changed dramatically since -- you know,

22 look at every decade, the '70s, the '80s, and the

23 '90s, with step increases in the quality of the

24 capability of the waste form and the waste package to

25 retain radioactive material.
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1 I mean, the burial method in the 1970s was

2 affectionately known as the "kick and roll method" of

3 waste disposal. And, you know, cardboard boxes were

4 disposal containers, and so on.

5 So I think that you have to keep in your

6 mind that as you march forward every decade there is

7 a whole lot of difference in what is disposed and what

8 the first two barriers are -- the waste form and the

9 waste packaging -- and what maybe the predecessors on

10 the Committee had in their minds when they were

11 thinking about all of this. Is that a fair comment?

12 MR. ESH: I think it's fair. The issue

13 becomes how much, even now, you can rely on the

14 engineering as you go out over extended periods of

15 time.

16 MEMBER RYAN: I'm not talking about an

17 extended period of time. I think we've beat that one

18 already. Let's move on off of that one for now. But

19 if you want to think about the disposal system, you

20 know, there are really some significant changes in

21 what that has looked like over time, and you have to

22 make sure that when you're talking about what happened

23 in the mid-1990s you are talking about what was, you

24 know, then a very much evolving and improving waste

25 form and waste packaging setting.
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1 MEMBER BLEY: I haven't read their letter,

2 rightly, but I also suspect they weren't talking about

3 DU. But you haven't come to my other question yet, so

4 I'll wait for that.

5 MEMBER POWERS: Well, the question I would

6 ask, Mike, is you are absolutely correct the way the

7 packaging for disposal has changed dramatically. And

8 the question is: why? Why have we gone from

9 literally throwing it in a cardboard box and dropping

10 it into a trench made with a backhoe in the back 40 to

11 more sophisticated systems?

12 MEMBER RYAN: There is a couple of

13 reasons, in my opinion, and I would ask the others to

14 offer their views. One is, as the disposal costs have

15 increased, and the disposal currency is volume,

16 efforts went into putting as much radioactive material

17 into a given volume as possible.

18 So processing water with resin, further

19 reducing resin volumes, using robust containers so you

20 can stuff more into it, and all those kinds of things

21 I think were part of the thinking. 

22 The other is I think utilities and other

23 generators of waste decide that accumulating waste on

24 their sites really wasn't part of their business. So

25 getting it processed and getting it disposed
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1 efficiently, quickly, and minimizing their inventories

2 of onsite wastes, was also going on at the time. I

3 think those are two of the key drivers -- all, again,

4 intermixed with the fact that pricing went from $3.50

5 a cubic foot to probably $350 a cubic foot. So that's

6 really the essence of the change.

7 MEMBER POWERS: All those things. And the

8 question I would tend to ask is, we could forecast

9 some continued development in that, and presumably

10 every step there makes the material less likely to be

11 dispersed into the environment. I make that

12 assumption. I don't know that it's true, but it seems

13 to me like it's true.

14 MEMBER RYAN: I think that's a general

15 trend for sure.

16 MEMBER POWERS: Is there a point where we

17 reach adequacy and one shouldn't do this better

18 engineering and what-not? Or is it always going to

19 occur?

20 VICE CHAIRMAN ARMIJO: That is a problem

21 with the time. You can have a material that you can

22 prove without any question that it will last 100

23 years, maybe 1,000 years, maybe 4,000 years. You get

24 out to 20,000 years, or 100,000 years, all bets are

25 off, because the environment is changing, there is an
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1 oxidation phenomena, there is a whole bunch of things

2 that can happen.

3 So if you keep the timeframe reasonable,

4 then I think you can reach a point where you can

5 demonstrate it and prove it, even to a critical

6 reviewer.

7 MEMBER RYAN: At some point, the criteria,

8 you know, for the performance of the site is where you

9 begin to ask or answer the question, Dana, that it's

10 time to stop. We know with some margin of uncertainty

11 being accounted for or some variability of the result

12 being taken into account that you can say, "This is

13 going to perform to the standard, we think, with a

14 reasonable confidence," so that we can say, "That's

15 enough." I think that's certainly doable.

16 But at the point you make that decision,

17 it's not just, how much does it cost and what is the

18 next cigar box we can put stuff in? It's, well, are

19 we meeting the objective, and is there a margin of

20 certainty that we are meeting the objective, which is

21 one of the questions you put forth earlier, Dave.

22 MR. ESH: I think whenever the regulation

23 was developed, and then through our performance

24 assessment working group and in our high-level waste

25 program, they all -- the staff all felt -- and I agree
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1 with them -- that we can make credible scientific

2 extrapolations over a 10,000-year timeframe.

3 We also felt that there isn't

4 significantly more uncertainty associated with going

5 to 20,000 than there is with 10-. There would be if

6 we went to 100,000 or a million, but there is not a

7 big difference in uncertainty space when you're

8 talking 10- or 20,000.

9 And based on the technical characteristics

10 of this problem, when we look at near-surface

11 stability, the characteristics of this specific waste

12 stream that the Commission gave us direction to try to

13 include in the framework, and radionuclide transport,

14 it all said we should step out a little bit longer to

15 account for those three things. And I will talk about

16 them in detail.

17 MEMBER RYAN: What the Commission wanted

18 you to include, are you talking about DU?

19 MR. ESH: Yes.

20 MEMBER RYAN: Uranium?

21 MR. ESH: Large quantities of depleted

22 uranium.

23 MEMBER RYAN: I hate to beg to differ, but

24 10- to 20,000 years isn't even a blink of the eye in

25 the decay of uranium.
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1 MR. ESH: No. But I will talk -- I will

2 talk about the waste characteristics in a slide here,

3 so let me get back --

4 MEMBER RYAN: Okay. All right.

5 MR. ESH: -- to it.

6 MEMBER RYAN: But, I mean, that kind of

7 needs some detailed --

8 MR. ESH: I'll explain it to you.

9 MEMBER RYAN: Okay.

10 MR. ESH: I think we talked about it at

11 the Subcommittee, but --

12 MEMBER RYAN: I just want to kind of --

13 MR. ESH: The second tier from the ACNW

14 principles was to evaluate the robustness of the

15 facility over the range of external processes and

16 events, and then also look at and ensure that no

17 significant changes in the dose from disposal site

18 will occur.

19 Well, that's fine to say, but what does

20 that mean? What is significant? If I have a dose of

21 25 millirem for the first 10,000 years, and then I get

22 a million millirem at year 50,000, is that

23 significant? Does that fail, or does that pass, you

24 know?

25 Right now, the approach we are taking is
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1 we are not specifying a dose limit for those later

2 times. We think the stakeholders deserve transparency

3 of information. And if NRC was regulating the

4 facility, we would consider those longer-term impacts

5 in the site environmental analysis. 

6 We think that is the proper context to put

7 something like that, because you are not locked into

8 a radiological licensing box. You are able to look

9 more generally at what the impacts are, are there net

10 benefits to the activity, those sorts of things, what

11 is transportation risk, all of the other components

12 that go into the evaluation.

13 You can put it in a better context, so the

14 staff -- I will talk about that in our

15 recommendations, but we feel we were consistent with

16 both of the sets of principles expressed by the ACNW

17 in some of their past discussions.

18 The ACNW also talked about things like

19 near-surface stability and -- what was the other one

20 I wanted to make sure I remembered to say? Oh, the

21 source term hazard characteristics. So one thing they

22 said is if you don't see the activity arriving at your

23 receptor location in this period of performance that

24 you select, then maybe you need to consider the source

25 characteristics of the hazard in defining that period
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1 of performance.

2 Well, in the case of uranium, that's going

3 to put you out at two million years or so if you are

4 considering the source characteristics of the hazard.

5 Is that what they intended, or not?

6 The last guidance that we got from the

7 ACNW on this topic prior to your March 18th -- prior

8 to the ACRS's March 18, 2010, letter was to maybe

9 consider the previous Committee evaluation to go with

10 a peak dose approach, because they said the peak dose

11 approach is going to consider all of these variable

12 conditions that determine when your peak dose occurs.

13 Whether it's different waste in a

14 particular facility, or whether it's the different

15 characteristics of different facilities, that will be

16 reflected in when the dose may arrive at a point in

17 time in the future. But I think the problem you run

18 into is for a material like depleted uranium, or other

19 long-lived isotopes that travel slowly in the

20 environment, is that really what was intended? I

21 don't think it was what was intended, and we

22 interpreted it differently. But maybe I'm wrong.

23 So the general objectives that we used or

24 considered when we went through this period of

25 performance selection process is we wanted to provide
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1 protection to the present and future generations. The

2 difficulty is how you set that protection for the

3 future generations.

4 We also wanted to consider uncertainties.

5 We wanted to ensure that we communicate what the long6 term impacts are, and we wanted to facilitate

7 decisionmaking. This is something we were talking

8 about earlier. Is this going to facilitate

9 decisionmaking or not?

10 So what does the selection process look

11 like? Well, we did a literature review and tried to

12 determine what people consider, and they will

13 generally consider the characteristics of the waste,

14 what is the analysis frameworks, or what's the

15 regulatory framework that you are applying.

16 They will look at uncertainties.

17 Especially in performance assessment, we tend to look

18 at natural and engineering-associated uncertainties.

19 We do not look at technology-related uncertainties,

20 because the policy is it's -- they're intractable to

21 project over long periods of time, or even moderate

22 periods of time.

23 And we try to limit the speculation on the

24 societal uncertainty, so we do that with reasonably

25 conservative scenarios to apply to the dose
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1 assessment. So I think, Dennis, this was a question

2 you asked about, what are the scenarios associated

3 with the different things.

4 The intruder assessment is generally done

5 looking at whether the waste is distinguishable from

6 the natural media in that location, first of all. If

7 it is, then you're looking at a discovery scenario

8 where somebody starts putting in a house, they put it

9 in at the disposal facility, they dig up material, and

10 they say, "Oh, we put the house in in a bad spot.

11 There's barrels of stuff here. We need to stop."

12 So the dose assessment looks at a short

13 period of time of direct radiation exposure, maybe

14 some inadvertent dust inhalation, pathways like that

15 associated with a discovery scenario, what happens in

16 that evaluation.

17 If the material is indistinguishable from

18 the natural material, then you have an acute scenario

19 where somebody builds a house, if the material was

20 disposed of shallowly -- and shallowly, we are talking

21 the upper three meters of the land surface -- so they

22 can potentially put a house foundation into the waste.

23 The acute construction scenario, somebody

24 builds the house, takes 500 hours or so to build the

25 house, I believe it is, and they are exposed to direct
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1 radiation and dust exposure and those sorts of things,

2 but they are not drinking water or growing plants or

3 living there. They are just guys building a house,

4 basically.

5 If the material is disposed of more deeply

6 than that, then they look at a drilling scenario where

7 somebody tries to put in a water well, maybe a natural

8 gas well or some other type of well that they punch a

9 hole through it, some of the waste comes up with the

10 cuttings, and then they analyze the exposure pathways

11 associated with that scenario.

12 Only in the event that the material is

13 disposed of shallowly, and it's indistinguishable from

14 the natural materials, then do they analyze the

15 chronic scenario of somebody could live in the house,

16 and they have a garden. There's two types of

17 scenarios, generally, a resident -- a resident

18 scenario and a resident farmer.

19 The resident farmer is they have all the

20 pathways. They have cows and chickens and meat and

21 grow plants, and the plants are contaminated, and the

22 animals eat the contaminated plants, and so on and so

23 forth.

24 The resident scenario is just somebody

25 living in a house. They have a garden. You know,
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1 they sleep there, they have offsite time that they are

2 not exposed, onsite time that they are exposed, that

3 sort of scenario.

4 I don't know if that answered your

5 question or not.

6 MEMBER BLEY: And you can get me to a half

7 a rem with DU without killing me from heavy metal

8 poisoning first?

9 MR. ESH: I don't know the answer to that.

10 That's a good question. You can get to a half rem

11 with DU with large quantities of concentrated

12 material. That -- with large quantities of depleted

13 uranium, you have to keep it covered, you have to keep

14 it protected, from a radon perspective. 

15 And all you have to do is think about the

16 radon in your house and what are the concentrations of

17 uranium that are driving the radon concentrations in

18 your house, just to understand, if you have

19 concentrated uranium, and large amounts of it, how it

20 can translate into a problem, especially from a radon

21 perspective.

22 MEMBER RYAN: David, isn't there an

23 equilibrium question there? I mean, if you have DU,

24 it's going to be way, way, way down the road before

25 you even have to think about radon.
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1 MR. ESH: There's an in-growth equilibrium

2 question that comes into play, yes. It has to --

3 MEMBER RYAN: Depleted uranium materials

4 -- it's going to be --

5 MR. ESH: It has to --

6 MEMBER RYAN: -- way longer than any

7 period of time we have talked about today.

8 MR. ESH: It has to come in over time, but

9 I will talk about that on the waste characteristics

10 slide. Remind me to go back to it.

11 MEMBER BLEY: Have you guys done any

12 calculations to support this?

13 MR. ESH: We have done a variety of

14 calculations to look at the impacts, yes. In the SECY

15 paper in 2008 for 08-0147, we did a technical analysis

16 to look at, well, do we need to do this rulemaking?

17 What's the issue here? And if you dispose of the

18 material shallowly, or you dispose of it at a humid

19 site, those are the two most direct pathways to cause

20 a problem. You can --

21 MEMBER BLEY: I'm sure I looked at that

22 SECY paper. Do we have -- I want to see that, so --

23 we'll get that.

24 MR. ESH: Yes. Yes. Feel free to look at

25 it.
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1 MEMBER BLEY: Is that the best source

2 you've got?

3 MR. ESH: That's the best source we've

4 got, yes.

5 MEMBER BLEY: Okay. I'll take a look.

6 MR. ESH: And what we tried to do there is

7 we didn't present the material in dose outputs. We

8 presented it in percentiles of various configurations

9 that would exceed the limits, because we were trying

10 to do an analysis that represented a whole range of

11 site conditions that could apply over the whole

12 country and disposal depths. 

13 So it doesn't make sense to average that.

14 You know, we have this issue of what -- if you're

15 doing an analysis at a particular site, you have

16 intra-site variability, but not inter-site

17 variability. And that analysis had to look at both

18 intra- and inter-site variability. So --

19 MEMBER BLEY: And I take it since you only

20 regulate the radiotoxicity you didn't look at whether

21 the chemical toxicity would have beat you to the

22 punch.

23 MR. ESH: We did not, and we also didn't

24 look at things like, at what point does a soil-to25 plant transfer factor no longer apply? So when you
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1 get the X percent uranium, or X parts per million

2 uranium, maybe plants don't live anymore.

3 I did work with a colleague that -- he had

4 experience on a project where the uranium

5 concentrations were much lower than what we are

6 talking about here, and he said, "The trees actually

7 turned yellow from taking the uranium up into trees."

8 MEMBER BLEY: The heavy metal aspect of

9 it.

10 MR. ESH: Yes, yes. 

11 MEMBER BLEY: That's what I suspect is --

12 MR. ESH: Commenters asked us about that,

13 though. They said --

14 MEMBER BLEY: I'm sorry. Who? Oh,

15 commenters.

16 MR. ESH: Commenters asked us about that

17 on the comments on the rulemaking package as -- what

18 about the chemical toxicity, not just the radiological

19 toxicity?

20 MEMBER RYAN: Well, I mean, correct me if

21 I'm wrong, but my understanding is it's more of a

22 chemical toxin than it is a radio toxin, from a human

23 exposure perspective.

24 MR. ESH: Early on, but as the material

25 ages and Mother Nature puts the daughter products
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1 back, it does not -- this is not a trivial material to

2 deal with. 

3 MEMBER RYAN: No, no, I agree with you.

4 MR. ESH: I'm not going to try to assert

5 -- because I haven't done the calculations -- how the

6 chemical risk compares to the radiological risk. The

7 chemical risk is EPA's business. I'm just telling you

8 that the radiological -- huh?

9 MEMBER RYAN: It's also OSHA's business.

10 MR. ESH: Yes. The radiological risk is

11 what we are managing, and the radiological risk can

12 become significant.

13 MEMBER SIEBER: And it gets worse with

14 time.

15 MR. ESH: Yes.

16 MEMBER RYAN: Long time. If you have pure

17 uranium materials, I guess I would ask that we address

18 that question in detail is -- what is the period

19 before I get to an equilibrium with radium-226 before

20 radon becomes an issue?

21 MR. ESH: I'd say, Dr. Ryan, you can look

22 at the appendix to the technical basis document --

23 MEMBER RYAN: Okay.

24 MR. ESH: -- where we did a couple of

25 calculations of just soil resuspension and inhalation
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1 of that, and then a simple calculation of radon at I

2 think it was 10,000 years, or maybe it was 1,000. And

3 you can look at those numbers. Both of those numbers

4 are -- maybe I'm not remembering. Both of those

5 numbers were over 500 pretty easily, over 500

6 millirem. You are talking --

7 MEMBER RYAN: Okay.

8 MR. ESH: You are talking like 5,000

9 millirem. It's because it is concentrated uranium.

10 If it's concentrated any metal, it's going to be hard

11 to deal with. I don't care whether it's uranium,

12 lead, mercury, zinc.

13 MEMBER RYAN: But the devil is in the

14 details. You assume all the radon produced readily

15 escapes from the matrix of the material without decay?

16 MR. ESH: No. You apply an emanation

17 factor, like you normally do for any material. And

18 emanation factors are all over the map from .02 to .7,

19 depending on the material and the natural conditions.

20 So this isn't a I guess make it a problem problem,

21 it's a what's the material we are dealing with, let's

22 assess it problem. So --

23 MEMBER RYAN: All I'm suggesting is that

24 the devil of -- you know, or the importance of some of

25 these things is in the details of what the assumptions
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1 are and the calculations supporting it. I mean,

2 that's an obvious thing to say, but, you know,

3 sometimes, you know, reasonable people can disagree

4 about what reasonable assumptions are to make these

5 calculations.

6 MR. ESH: Yes. I would say it's easy --

7 you can look at -- think of the problem this way. The

8 uranium -- natural uranium ore bodies in the U.S. are

9 a few tenths of a weight-percent uranium. Okay? And

10 in a few places, like Canada, they have some that are

11 very high, 40 weight-percent or more uranium. 

12 They have to do robotic mining at those

13 locations because of the radiation levels. And if you

14 put a lot of depleted -- concentrated depleted uranium

15 in one facility, it's a hard problem to deal with.

16 That's not an easy problem. 

17 It doesn't matter what you do with the --

18 you could do the analysis very conservative and make

19 it an extreme problem. But you can do a credible

20 analysis and even a non-conservative analysis, and it

21 is still a challenge that you need to deal with.

22 Whenever we looked at the selection

23 process, something that we talk about in the paper --

24 I'm not going to cover today -- is the

25 transgenerational equity and discounting and all of
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1 that that comes into play. It's kind of softer to

2 engineers, but it's important for this problem.

3 We didn't attempt to do -- you could do a

4 socioeconomic evaluation to set a period of

5 performance, and you could use that to argue what you

6 would set it at for any material, that that's what you

7 should do for society. That's a much more complicated

8 problem, and we didn't attempt to do that here.

9 VICE CHAIRMAN ARMIJO: It's very

10 subjective, too..

11 MR. ESH: And it's also very subjective,

12 you're right.

13 VICE CHAIRMAN ARMIJO: But, you know, the

14 fundamental problem I have with this is that future

15 generations -- your basic assumption is that future

16 generations and their governments, the people and

17 their governments, are unable to protect themselves.

18 They have lost memory of what is out there. They

19 don't seem to -- they don't -- they are basically

20 incapable of protecting themselves, and I don't share

21 that.

22 MR. ESH: I don't think it's a matter of

23 that they're incapable of protecting themselves. But

24 the way these processes work is the radioactivity

25 exits the facility nominally, usually, in 61.41,
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1 through the groundwater pathway, ends up in an

2 aquifer, and eventually ends up in a water supply of

3 some sort, whether it's a stream, a well, a public

4 water supply, whatever the type of water supply it is.

5 You don't know that the radioactivity gets

6 into your water supply until you find it in your water

7 supply. 

8 Now, you could argue that people are going

9 to be testing and analyzing their water supplies, and

10 they do it now, and they analyze it for radioactivity,

11 and they would have a gross alpha or gross beta

12 measurement of some sort, and they'd say, "Hey, we're

13 starting to get radioactivity in our water supply that

14 is above what we intended."

15 But over these timeframes, I think you

16 have to have continuity of -- you have to have

17 continuity of this understanding that relies on things

18 like records and things that aren't durable. I would

19 say, has any of you ever held a 500 year-old record?

20 I doubt any of you have ever held a 500 year-old

21 record.

22 VICE CHAIRMAN ARMIJO: Yes, I've had

23 books.

24 MR. ESH: Well, okay.

25 MEMBER BLEY: Through a glass.
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1 (Laughter.)

2 VICE CHAIRMAN ARMIJO: Go to Salamanca

3 University and you will get 1,000 year-old books.

4 MR. ESH: The point is that it's much more

5 unlikely than likely that you have done that.

6 VICE CHAIRMAN ARMIJO: You make an

7 assumption and you assert that society will basically

8 become less confident in the future than they are

9 today, and, therefore, you have a current obligation

10 to generations in the future, assuming that they can't

11 protect themselves at all. And I don't share that.

12 MEMBER BLEY: And I'm not sure if I'd go

13 as far as Sam, but I'm -- you just mentioned that --

14 and I'm not saying go do a socioeconomic analysis, but

15 you said, "Wow, that's a big analysis. That's hard."

16 The impact of this proposed change I think

17 will direct that kind of effort and what this is going

18 to require for people to do to respond to it. So, you

19 know, analysis is cheap by comparison I think to --

20 MR. ESH: But in what way, because the

21 period of performance is undefined right now, and our

22 Agreement States have used anything from 500 to peak

23 to 50,000. So I don't understand what the big -- the

24 big opposition to this is when they do it that way

25 right now. 
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1 And in the field of performance assessment

2 -- this isn't an NRC issue. Performance assessment

3 uses these long periods of time and this type of

4 analysis internationally. So if you want to make the

5 comment of "It's the wrong way to do it," you are free

6 to do that. That's what -- we don't have the ability

7 to change the international framework of how

8 performance assessment is done.

9 VICE CHAIRMAN ARMIJO: I'm not saying we

10 need to attempt what the international folks do. We

11 have to do what's reasonable and practical for the

12 United States. And if this is just a depleted uranium

13 problem, then there may be a better way to treat it.

14 That's why I got to my earlier question,

15 is there some preferred form, waste form, in which a

16 lot of the engineering uncertainties -- radon

17 emanation, stuff like that, would be more tractable

18 than as powders or filings and stuff like that, and

19 you can push towards a favorable form, so that it

20 makes the engineering problem much more -- you could

21 deal with it.

22 MR. ESH: Yes. And what I will try to

23 show you here is that the rulemaking was initiated in

24 part because of the depleted uranium issue. But I

25 would argue that the issue is more generic than that.
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1 VICE CHAIRMAN ARMIJO: Well, okay.

2 MEMBER RYAN: Let me -- it will just take

3 me 20 seconds to advise the members. We have about a

4 half hour to go on this Subcommittee. We do have some

5 more time scheduled for it down the line. I'm going

6 to ask that we maybe let David get through this

7 slides, and if you have questions that you mark them

8 as we go along. And maybe we can handle some of them

9 today, maybe we'll take them up after we consider them

10 in more detail between now and our next meeting. Fair

11 enough?

12 VICE CHAIRMAN ARMIJO: Sure.

13 MEMBER RYAN: Thank you.

14 MR. ESH: So waste characteristics here is

15 one thing that people generally consider, and even the

16 ACNW mentioned for us to consider, and we did, and we

17 looked at, okay, what is the activity of low-level

18 waste compared to something like a depleted uranium

19 waste stream?

20 And I generated this figure on the left,

21 which I -- now, if there's one regret I have in this

22 process, I wouldn't have, because I think it has

23 caused a lot of misunderstanding. 

24 The performance assessment is, of course,

25 about ensuring that you contain the short-lived
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1 material. But ultimately the performance assessment

2 is about not this 99 percent that decays in place, but

3 it is about the one percent that remains and whether

4 it can cause an undue risk to somebody.

5 So the performance assessment is about

6 what is happening for this fraction that ends up out

7 at some longer time. You can argue about what that

8 longer time should be. It's not about the material

9 that is short-lived. The short-lived is easily

10 managed with the engineered features and controls that

11 people use today.

12 The issue of -- this issue is an

13 aggregation issue, I think, so the material that is

14 presented here is on a radionuclide basis. But when

15 you aggregate the issue on a facility basis, what I'll

16 show in a few slides here is that all our current

17 facilities have long-lived waste in them. And they

18 have what I would say are fairly significant amounts

19 of long-lived waste.

20 So it's -- you can put depleted uranium in

21 it, which is another couple orders of magnitude

22 challenge in the problem, but the issue is not going

23 to go away. It applies to all of the existing

24 facilities that we have.

25 So this argument that maybe we should only
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1 consider 1,000 years, because most of the waste

2 decays, I would say that same argument applies to

3 high-level waste. Most of the high-level waste, or a

4 small percentage of it, remains at 1,000 years, just

5 like it does for the commercial low-level waste.

6 There is no reason to -- if you're just

7 looking at decay curves, to interpret those

8 differently. In either case, the performance

9 assessment is looking at what remains at some point in

10 time.

11 So on this figure on Slide 15, it's from

12 NUREG-1538, which the high-level waste program

13 developed. And they considered, well, what is the --

14 when does the material approximate that of a natural

15 ore body? That would be a good thing to know, because

16 that would say, okay, once it approximates a natural

17 ore body, why should I protect that any more than I

18 would worry about a natural ore body? I think that

19 makes a lot of sense if you're trying to regulate what

20 -- the safety over time.

21 In this case, they looked at -- and it was

22 a site-specific analysis for Yucca Mountain. They

23 looked at when it approximated a natural ore body. It

24 was factoring in things like solubility limits and how

25 things reduce the dose or reduce the concentrations it
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1 may get out of the facility. 

2 But they came up with 10,000 as a pretty

3 good number for when disposal of high-level waste, in

4 a geologic repository, would approximate the risk from

5 that of a natural ore body. And I think that was a

6 good line of argument.

7 The problem is, for near-surface disposal,

8 it is completely different stability issues than for

9 geologic disposal. The other argument associated with

10 the geologic disposal is that if you have geologic

11 stability for 10,000 years, you are likely to have it

12 for much longer. That isn't the case for near-surface

13 disposal. Climate effects come in. Your near-surface

14 stability issues get worse over time. Just because

15 you might be able to demonstrate stability for 1,000

16 years doesn't mean your site is going to be stable for

17 10,000 years.

18 But the bottom line is that the period of

19 performance that had been selected in NRC policy

20 space, it's not a pure policy decision, such as,

21 what's the risk that -- what's the obligation I have

22 to a future generation over time? When do I have to

23 consider that future societies can mitigate their own

24 risks? 

25 That's not what has been done -- NRC
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1 policy. NRC policy is to consider these -- some of

2 these technical issues and use that to help formulate

3 the period of performance that is selected for a

4 particular problem. And that's what we did here.

5 So I also want to show you this analysis

6 that we did to give you some more context. We looked

7 at the actual inventories disposed at four different

8 low-level waste disposal facilities using the DOE MIMS

9 database. That database you can get information on

10 what has been disposed of at a particular facility by

11 isotope in a particular year. It does have some

12 limitations. Generally, it starts in the '80s for

13 each facility, and in some cases we know that some

14 significant disposals occurred prior to the time that

15 the database starts.

16 And also, some of the information may be

17 complete -- incomplete, because we got information on

18 Agreement -- from Agreement State regulators on actual

19 uranium disposals. And the database was generally

20 lower than what we got from the Agreement State

21 regulators.

22 But what I'm going to show you here is we

23 calculated the reduction factor that you need from the

24 waste to the groundwater to meet the 25 millirem, to

25 show you on an isotopic basis, what are you dealing
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1 with in low-level waste.

2 The performance assessment process is how

3 you go about to verify that you are going to get those

4 reductions. So you look at things like sorption and

5 solubility and dispersion and dilution. That's the

6 whole performance assessment process.

7 The next two slides are not performance

8 assessment results. They are just trying to give an

9 apple-to-apple comparison for material.

10 So if we look at this figure on Slide 17,

11 this is a plot of the reduction factor versus the

12 half-life of the materials. What you see is that at

13 the -- in a given row here, it gives all of the

14 isotopes for the four different facilities by symbol

15 by half-life. So this row is strontium-90. That's

16 the amount of strontium-90 that has been disposed of

17 at four different facilities.

18 Next is americium-241. I only included a

19 couple of short-lived isotopes on here. It wasn't

20 necessary to put them all on here, because they -- it

21 has the same general behavior. But I did put a lot of

22 the long-lived ones for which inventory is reported,

23 including uranium-238 and thorium-232.

24 And what you see from this figure -- and

25 I would argue -- is that you have increasing challenge
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1 -- and I think the Committee has expressed this -- as

2 you need bigger reductions, and you have longer-lived

3 material. Longer-lived material and bigger reductions

4 is a much harder technical problem. It is going to

5 require you have more knowledge about your site and

6 more basis for what is going to happen.

7 The Commission direction to include

8 blended low-level waste or large quantities of

9 depleted uranium, add these red symbols up at the top.

10 It's an increase in the concentration of material that

11 you are dealing with in each case, whether it's long12 lived waste or whether it's short-lived waste.

13 The other point I would like to make is

14 that here is a group of symbols associated with

15 uranium-238 and thorium-232. That is already disposed

16 of in the facilities. All of these four facilities

17 have a decent amount, or large amount depending on

18 your perspective, of long-lived waste.

19 The Commission direction to add large

20 quantities of depleted uranium takes that out further.

21 But the issue of long-lived waste is still present in

22 low-level waste disposal.

23 Now, this isn't quite the full picture,

24 and I also should caveat it that this is just the

25 parent nuclide and the water pathway. What you'd
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1 really want to know is all the pathways and the decay

2 change, what comes in in the daughter. 

3 So when you're looking at uranium-238,

4 you're -- not all the daughters. You talked about,

5 well, what is the -- it's pure uranium. This is just

6 the pure uranium impact. It's not the lead-210 and

7 the radon and everything else that comes in down the

8 line. 

9 So you need a significant reduction out of

10 your facility to get to your performance objective in,

11 say, ground water for some of these isotopes.

12 Now, that -- you say, well, that's fine

13 and good, but you can't get from waste to water

14 directly like that. There's things that go on.

15 So this next slide on -- figure on

16 Slide 18 is we said, "Well, let's factor in

17 geochemistry, and we will use a geometric mean

18 distribution coefficient for these different elements

19 as a proxy for how much geochemistry is going to

20 reduce the risk of these elements."

21 And what we have shown here is that for

22 something like the thorium it drops down much more

23 significantly than the uranium, because the thorium is

24 more insoluble, less mobile in the environment,

25 compared to the uranium, which is kind of moderately
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1 soluble, moderately mobile; unless you are in reducing

2 conditions, then uranian can become very immobile.

3 So, you know, if you want to talk about

4 technical things that you could do to mitigate

5 uranium, well, the best thing you could do is put it

6 in a reducing environment, which would probably not be

7 a near-surface environment. There are many other

8 reducing environments that you would consider.

9 MEMBER RYAN: Put in reducing agents.

10 MR. ESH: Or put in reducing agents,

11 enough reducing agents that you had confidence of

12 maintaining those reducing conditions. Very good

13 point, Dr. Ryan.

14 So the point being that the technical

15 requirements in the rule have to allow you to

16 distinguish when you have a significant quantity and

17 when you may need an inventory limit, and when you

18 might not need an inventory limit. 

19 And what I would argue is that the

20 intruder analysis, especially with the shorter-lived

21 waste, assuming that it's an intruder analysis that

22 allows you to take into some consideration some things

23 that would mitigate that risk, like land use and

24 proper scenarios and those sorts of things, it is

25 important for the blended waste especially, but any
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1 concentrated short-lived waste, it doesn't have to be

2 blended waste, that's just the thing that came up at

3 this time to put it into our rulemaking.

4 Likewise, the long-lived waste, the period

5 of performance affects how you would determine whether

6 you've taken too much or whether you've taken an

7 appropriate amount of that material. 

8 The period of performance, if you set it

9 very short, just by the basis of the transport through

10 your aquifer system, it could be arriving after your

11 compliance period, and it could cause a very large

12 impact. You get delays in your system from the site

13 characteristics or the engineering. You want those

14 things, but you also want to understand what your

15 risks are, especially as you go out in time.

16 And so the period of performance and the

17 intruder analysis were the two parts of the regulation

18 that we felt that deal with these different types of

19 more concentrated materials. It doesn't matter when

20 it's called blended waste or depleted uranium. If

21 it's long-lived concentrated material, or if it's

22 short-lived concentrated material, these are the two

23 areas of the regulation that we felt were -- needed

24 the requirements to mitigate those risks.

25 This is a conceptual figure. I won't
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1 spend a lot on time on it. It's just trying to convey

2 uncertainties. I think the Committee has talked about

3 this issue of technology, and to me I agree with you

4 that technology is a big factor in what the risk --

5 the actual may be over time. 

6 I just don't see how you credit it in the

7 regulatory analysis, because many stakeholders out

8 there, a lot of academics and other regulatory

9 communities, they don't credit something like that,

10 and they say it's because you can't project those

11 things accurately over the assessment period.

12 MEMBER RYAN: Just one comment on that

13 point, David. I think -- and, again, I have said it

14 many times, but, you know, you are part of a very

15 talented performance assessment crew that has insights

16 in all of this. And whether it's probably not in the

17 regulations the best place, but I can see the need for

18 NUREG guidance and other kinds of technical analysis

19 guidance documents that will take a licensee through

20 some of what the details of this are, because as I

21 think we would all agree, the devil in this is in the

22 details and what you do and how you calculate it and

23 all the rest. So --

24 MR. ESH: Yes.

25 MEMBER RYAN: -- somewhere this, you know,
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1 knowledge that you and the team have amassed needs to

2 be put forth, so that everybody can use it, and, quite

3 frankly, everybody is on the same page with what the

4 expectations are.

5 MR. ESH: Yes. And I think we've done

6 that. We have a guidance document that we are

7 developing in parallel with this, and it has quite a

8 bit of detail on all of these topics that hopefully we

9 can talk about at the Subcommittee meeting in August.

10 MEMBER RYAN: Sure.

11 MR. ESH: It's coming along. It's getting

12 close to a concurrence process document.

13 MEMBER RYAN: I just want to preview for

14 the other members that, you know, licensees won't be

15 in isolation trying to figure this out on their own.

16 MR. ESH: We recognize that these are not

17 easy problems and easy issues, and we felt very

18 strongly that we needed some guidance to go along with

19 this. And the rule text is not going to be issued in

20 a vacuum without that guidance. 

21 Guidance is a key part of it. It's just

22 a bigger effort, not by number of people but by

23 content of information, and it -- we didn't have it

24 ready to talk about at the same time as the rule text,

25 so --
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1 MEMBER RYAN: Okay.

2 MEMBER BLEY: Can I just ask one question,

3 because I lost the context. Early in the session Mr.

4 Camper said something about you were directed to risk5 inform some aspect of this problem. I don't remember

6 what it was, and I don't remember it from the SRM.

7 MR. CAMPER: What it was, when we did

8 SECY-08-0147, which is the SECY that is associated

9 with the depleted uranium question --

10 MEMBER BLEY: Okay.

11 MR. CAMPER: By the way, we did a

12 technical analysis.

13 MEMBER BLEY: Okay.

14 MR. CAMPER: When the Commission came back

15 in the SRM associated with that paper, it told us to

16 do two things. It said proceed to do a limited

17 rulemaking to require site-specific performance

18 assessment for large quantities of depleted uranium.

19 It also said to do another assignment, and that is to

20 budget to risk-inform the waste classification scheme

21 in 61.55.

22 MEMBER BLEY: Okay.

23 MR. CAMPER: We assumed "to budget" meant

24 to do, and that's how we are proceeding, with the

25 emphasis in FY13.
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1 MEMBER BLEY: Okay.

2 MR. CAMPER: But they also emphasized when

3 you do the risk-informing of the waste classification

4 scheme, take a close look at this thing called

5 depleted uranium when you risk-inform. That's the

6 assignment of --

7 MEMBER BLEY: Okay. Thanks for the

8 context.

9 MR. ESH: So on this uncertainty slide, I

10 am trying to convey a lot of different things. When

11 you go out to these very long times, you have to start

12 worrying about things -- extreme natural events. And

13 one argument that we hear is that, well, the

14 uncertainty is so large that we need to -- the numbers

15 are meaningless.

16 And I would say, well, you have to think

17 about that as what -- why should you take the action

18 if you don't know the impacts of the action? You

19 should have some confidence that you're mitigating the

20 impacts, and that they aren't significant. And the

21 process and the regulatory requirements should allow

22 you to get between those -- between Points A and B to

23 do that.

24 We do want to understand -- acknowledge,

25 though, that this waste disposal problem is in a much
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1 bigger context of what is going to be happening with

2 people, the world, and everything else. And those

3 uncertainties very well could be more significant.

4 But as I said, you are talking about a

5 different analysis, a different type of analysis, in

6 order to justify what you would pick out of that

7 outcome, an analysis that we haven't done, and I'm not

8 aware that anybody has done, in any international

9 waste development program.

10 So it's something that, you know --

11 VICE CHAIRMAN ARMIJO: Maybe the basic

12 problem is you really shouldn't treat this as a bury13 and-forget issue, because the analysis gets to be so

14 complicated and so -- so much uncertainty in it for so

15 long a time that a more practical way is a periodic

16 reassessment. 

17 It is never really buried permanently

18 unless, you know, every 50 years somebody does a

19 reassessment and somebody pays for it and says, "We'll

20 go as we" -- you know, because every step in this

21 analysis, whether it's materials degradation, whether

22 it's flooding, whether it's land movement, whether

23 it's societal issues, it's open ended. And any

24 scenario that you put together, and any number you put

25 out, is readily challenged by any number of people.
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1 MR. ESH: And that is a comment under our

2 options considered here, Option 5, as we consider an

3 option that would be like an industrial metals

4 approach, which is what you just described.

5 VICE CHAIRMAN ARMIJO: Okay.

6 MR. ESH: And in the end, we didn't select

7 that option, because that's not the Commission's

8 policy or framework for managing this type of problem.

9 The Commission, whether it's in uranium mill tailings,

10 low-level waste, decommissioning, or high-level waste,

11 they do not take that approach.

12 MEMBER RYAN: One thing, David, I think is

13 certainly catching my attention in going through this

14 again with you all is this -- a couple of times we've

15 heard about, well, you know, we're following the

16 Commission direction, which is all well and good, but

17 I get the sense that some of these other options that

18 weren't in the Commission direction might have been

19 beneficial to evaluate.

20 So there is something I think very

21 important for the Committee to understand that, you

22 know, maybe the SRM and the direction to the staff

23 wasn't wide enough.

24 MR. ESH: Well, I think that the issue

25 that was first presented to the Commission was how you
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1 go about managing or classifying this particular

2 material. 

3 And some options were presented to them in

4 the SECY-08-0147 Commission paper, one of which was,

5 well, let's just analyze it the same as the materials

6 that did end up in the regulation were analyzed,

7 because Sandia National Lab developed an optical

8 character recognition program and got the old programs

9 running.

10 We could just throw uranium into those

11 programs and generate a number for it, and then put a

12 uranium number in the table. So that would be -- that

13 would have been one solution. They opted not to

14 choose that, I think in part because they wanted to

15 recognize that that approach, while sufficient, was

16 not necessarily risk-informed, because you're applying

17 the same analysis and same conditions to all sites, no

18 matter what their conditions and natural variability

19 may be.

20 So they were presented with options within

21 how to do the waste classification part of the

22 problem, which then led to this rulemaking process and

23 these changes we are attempting to do here, but this

24 bigger issue of what's the overall framework, you are

25 asking questions that are much bigger than the
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1 direction that we received for the limited scope

2 rulemaking. 

3 And I hope we would consider it within the

4 broader effort that we do in the future, if it's

5 budgeted for. The Commission has to decide if this is

6 a priority and whether they want to -- want us to do

7 that activity or not.

8 MEMBER RYAN: I think some of the sticking

9 points, though, are in that latter space, rather than

10 in the -- that's my view of it.

11 MR. CAMPER: Allow me to make a comment or

12 two on this point, because several times in your

13 Committee you have touched upon this, and let me just

14 give you sort of a pragmatic viewpoint about it.

15 MEMBER RYAN: Just tell them who you are

16 again.

17 MR. CAMPER: Larry Camper. I'm sorry.

18 The challenge that we face as a staff, and that the

19 Commission faces, really, is indeed a practical,

20 imminent problem. The disposal of depleted uranium

21 and the disposal of blended waste is before us. It is

22 imminent. The disposal of these two types of products

23 is imminent.

24 When we started wrestling with these two

25 issues and communicating with the Commission, first,
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1 on depleted uranium, and then when we briefed the

2 Commission on blending, and the Commission directed us

3 to add blending to this particular waste -- to this

4 particular rulemaking -- during that same briefing

5 this question of, what about Part 61 at large came up.

6 And we do have that assignment, as I

7 mentioned earlier, and we have identified another

8 SECY, we have identified five options in that SECY

9 from looking at Part 61 overall. At least one of the

10 Commissioners, in fact two of the Commissioners, were

11 quite concerned about even adding blending to this

12 particular rulemaking, because of the concern that if

13 this rulemaking got bogged down it could have an

14 impact upon the ability for industry to dispose of

15 blended waste.

16 So what you have in the final analysis,

17 then, is two issues that are imminent at this time,

18 that being the disposal of large quantities of

19 depleted uranium -- and, yes, the Department of Energy

20 has a very large quantity sitting on pads at Paducah

21 and Portsmouth at this point in time, which were being

22 exposed to the environment over time.

23 And, yes, the question of blending is

24 going to become a reality, it would appear.

25 MEMBER RYAN: Just so I'm clear, Larry,
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1 the industry waste that you're talking about is

2 Department of Energy uranium-related waste.

3 MR. CAMPER: That's correct.

4 MEMBER RYAN: So it's not industry waste.

5 It's not what these folks around this table --

6 MR. CAMPER: But they do want to dispose

7 of a portion of it in the commercial facilities.

8 MEMBER RYAN: Fine. But it's DOE uranium

9 waste, not --

10 MR. CAMPER: Correct.

11 MEMBER RYAN: -- licensees or the NRC and

12 Agreement State waste.

13 MR. CAMPER: I'm only pointing out that

14 these two challenges are imminent.

15 MEMBER RYAN: Okay. That's fine. I just

16 want to make sure we frame exactly what we're talking

17 about.

18 MR. CAMPER: And then, the question of

19 looking at the Part 61 much bigger, you raise many

20 very good question about Part 61 and its construct.

21 The thing we have to be cautious about, though, is

22 that Part 61 is well known, it's established, it's

23 adequate to protect public health and safety. It's

24 not perfect.

25 And any movement into -- when we start
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1 moving more closely into recommendations to the

2 Commission about what to do about Part 61, which we

3 owe in December of '12, I think will head into,

4 depending on what the Commission decides to do, of

5 course, a very extensive rulemaking that will take

6 minimally, in my view, at least four years.

7 And so you have to weigh -- all I'm saying

8 is you have to weigh the challenges that are before us

9 now juxtaposed against what it would mean to look at

10 this regulatory part that has been around for 30-plus

11 years that has worked, overall, rather well. So just

12 a practical observation.

13 MEMBER RYAN: Thank you.

14 MR. ESH: So I have eight minutes and

15 eight slides.

16 MEMBER RYAN: No, you have seven minutes.

17 MR. ESH: Seven minutes and eight slides.

18 (Laughter.)

19 So we considered options. We -- in the

20 paper that you hopefully have and looked at, we had

21 some rating factors that we developed and tried to, at

22 least in a qualitative manner, evaluate these options.

23 What we ended up with is -- our recommendation was for

24 Option 3, a two-tiered approach, which was consistent

25 with past ACNW direction. 
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1 We have a compliance period of no less

2 than 20,000 years, with a 25 millirem TEDE limit.

3 This is for 61.41. And then, a requirement to perform

4 a calculation over these long times to provide

5 transparency of information to stakeholders that we

6 wouldn't apply a dose limit to in the regulatory

7 analysis.

8 If NRC was regulating those facilities, we

9 would take those impacts, whatever they may be, into

10 account in the site environmental analyses which are

11 performed.

12 And then, we also reflected in the changes

13 -- we wanted to highlight the uncertainties associated

14 with the disposing of long-lived waste and that

15 limitations on disposal of these uncertainties may be

16 needed to properly manage the uncertainties. This was

17 clear to us in Commission direction that was given to

18 us in the SRM on that 08-0147 paper.

19 And, let's see, our basis for the 20,000

20 years, it had three elements to it primarily. We

21 looked at the performance objectives, and we wanted to

22 consider groundwater transport, the characteristics of

23 the waste, and site stability. We also looked at the

24 basis and the context for other numbers that were --

25 have been used in waste management programs.
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1 So the first area I will talk about is

2 this near-surface stability, and near-surface disposal

3 is not geologic disposal. It has much more

4 challenging stability issues.

5 The climate cycling is pretty well known

6 or expected. This value of 10,000 years that we could

7 apply is more likely to be in a period of climate

8 transition. We wanted to include -- in the end, we

9 decided we wanted to include climate cycling within

10 this compliance period for long-lived waste, because

11 it should encourage the disposal of long-lived waste

12 at stable sites as opposed to unstable sites.

13 And the regulation is very clear. It

14 says, "A cornerstone of disposal is stability." There

15 was no intention in the low-level waste framework to

16 ever take material that you were going to lose control

17 of, or that was going to be released into the

18 environment in a large fashion, regardless of whether

19 that was going to happen at 100 years, 500 years, or

20 10,000 years, the framework was designed to handle low

21 concentrations of long-lived waste and moderate to

22 high concentrations of shorter-lived waste.

23 So if you are going to put other materials

24 into the framework, you need the requirements to

25 distinguish between when that action is appropriate
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1 and when it is not appropriate.

2 A second thing that we considered was the

3 characteristics of the waste, and, in this case, the

4 direction from the Commission, the rulemaking derived

5 from depleted uranium. And as we talked about,

6 depleted uranium has this long in-growth

7 characteristics over long -- or has daughter in-growth

8 characteristics over long periods of time.

9 This value of 20,000 years better captures

10 what is happening with depleted uranium specifically

11 than does 10,000 years. And you say, "Well, it's not

12 much in the context of depleted uranium." Well, at

13 1,000 years, you are off by about a factor of 1,000

14 from where the depleted uranium concentration is and

15 its daughters and what risk it could cause compared to

16 where it ends up at the peak.

17 And I talked about uncertainties. You

18 have a vast -- large amount of uncertainties.

19 MEMBER RYAN: "Vast" is the right word.

20 MR. ESH: Vast, better. Okay. Waste

21 characteristics are something that you know pretty

22 well. So you should, at a minimum, at -- when you are

23 considering developing, say, a period of performance,

24 consider the waste characteristics that you are trying

25 to develop the regulation for. And this regulation is
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1 to apply to depleted uranium.

2 When you are at 20,000 years, you are

3 getting close to a factor of 10 for depleted uranium.

4 And I think I can get in front of stakeholders and

5 talk about uncertainty and say, "I'm doing the right

6 thing when I'm only off by a factor of 10." I don't

7 know how I'd make that argument when I'm off by a

8 factor of 1,000 when we know what the characteristics

9 of the material is.

10 So I think that argues -- in our mind, it

11 argued for a period of around 20,000 years would help

12 us accomplish that.

13 MEMBER RYAN: I guess the one thought I'd

14 offer -- and I'm sure we can talk about it more next

15 time -- is that that is one element of what --

16 MR. ESH: That's one. We have a few

17 elements that we considered. We --

18 MEMBER RYAN: But there's a hundred more

19 to think about.

20 MR. ESH: Well, there may be lots of

21 others to think --

22 MEMBER RYAN: Lots of others.

23 MR. ESH: There may be lots of others to

24 think about, but, like I said, this wasn't done in a

25 vacuum. We did a detailed literature review of what
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1 is done internationally and in various programs. And

2 I think we are pretty much in alignment with that.

3 The Europeans generally would say, "We

4 should be going way out longer for these types of

5 materials than this 20,000 years." They are much more

6 comfortable going out to long timeframes, and they

7 generally do, whether it's for radiological materials

8 or industrial materials.

9 MEMBER RYAN: But by the same token, they

10 end up backing up into an inventory limit for a site.

11 MR. ESH: Well, that's the point. If you

12 don't develop the appropriate criteria to identify

13 when you need an inventory limit, then how are you

14 going to generate -- how are you going to develop the

15 right inventory limit? 

16 They used this criteria to develop

17 inventory limits and assure, regardless of when it

18 gets to people, they are going to limit it to what

19 they want to limit it to. And I would argue that we

20 need at least 20,000 years to develop the -- for the

21 analysis to be done to determine those inventory

22 limits for this type of material.

23 MEMBER RYAN: That's a whole different

24 system than a concentration-based waste system.

25 MR. ESH: Well, the concept of inventory
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1 limits is not new in this regulation. It exists in

2 the regulation. It's very clear for long-lived waste

3 that they expect that inventory limits would be

4 generated when needed. The question becomes how you

5 develop those inventory limits. 

6 And what I'm saying is the period of

7 performance is one of those things that you need to

8 tell you what analysis to do to develop the inventory

9 limit. 

10 So on this Slide 24 it's a bit

11 complicated. This is really a three-dimensional

12 table. But what I'm trying to show you here is how

13 the change in period of performance would affect which

14 radionuclides you expect to see under different

15 conditions.

16 So if you look at, say, the upper right17 most box in the table, what that is showing is that at

18 a deep arid site, at 10,000 years, you are probably

19 not going to see much of these radionuclides. As you

20 go to 20,000 years, or 50,000 years, then you capture

21 them within your analysis.

22 VICE CHAIRMAN ARMIJO: I'm missing the

23 time scale. That's what I was looking for.

24 MR. ESH: The time is embedded in the

25 results of this analysis. This is the delta of the --
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1 of what radionuclides that you capture in your

2 compliance analysis as you go from 10- to 20,000 or

3 50,000. So the time is reflected in what nuclides

4 show up in which boxes of these -- of this table.

5 VICE CHAIRMAN ARMIJO: Can I see the time

6 -- can I get the time from a color code? I'm trying

7 to find out where the time -- where I get the

8 timeframe.

9 MEMBER RYAN: It's not on there.

10 MR. ESH: The time is not on there. The

11 time -- like, for instance, if the time was -- if I

12 set this at 1,000, all of these radionuclides would

13 not be in any of the boxes. Well, actually, the

14 technetium, tritium, chlorine would probably show up

15 at the humid, shallow site, maybe iodine.

16 MEMBER RYAN: Carbon, iodine.

17 MR. ESH: Maybe carbon. But, almost

18 definitively, things like strontium, neptunium, and

19 everything on the other sides of those diagonals would

20 not show up in your analysis.

21 MEMBER BLEY: So you could have a series

22 of these is what you're saying. So this one is at a

23 1,000 --

24 MR. ESH: This is to show the delta for

25 going longer from 10,000. I could also make a similar
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1 thing to going shorter to 1,000. But based on the

2 waste characteristics, we didn't really consider

3 strongly the --

4 MEMBER BLEY: Well, that's why I'm having

5 trouble. You said the delta. I could see how this

6 would be what's there at one time period, but the

7 delta -- this is --

8 MR. ESH: This shows more of what you

9 capture in the analysis as you -- as I would change

10 the period of performance from 10,000 to 20,000 --

11 MEMBER BLEY: Yes.

12 MR. ESH: -- this shows what would show up

13 under these particular conditions. On the upper --

14 MEMBER RYAN: That wouldn't have been --

15 the way you explained it before is things above the

16 blue line and below the blue, if you look, you go from

17 sites with fast water flow in the lower left to sites

18 with slow water flow in the upper right.

19 MR. ESH: Yes.

20 MEMBER RYAN: And as you go out in time,

21 things go from -- if I remember right, David, things

22 go below the line.

23 MR. ESH: The lines are like this. So

24 these are classes of radionuclide at given site

25 conditions. So say you have a deep, arid site, the
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1 transport times are really, really long for a deep,

2 arid site. So things like technetium, tritium, and

3 chlorine might not even show up in 10,000 years. As

4 you go to 20-, you start seeing them. Okay?

5 But if I go to the box in the other part

6 of the corner, other part of the table down here, at

7 a shallow, humid site, zirconium, thorium, and cesium

8 show up as I go from 10 to 20. But if I'm shorter

9 than 10,000, they don't even show up at the shallow,

10 humid site. They are off the table, basically.

11 There are some things -- radium, lead, and

12 americium -- that don't show up under any conditions.

13 MEMBER RYAN: David, we're going to have

14 to wrap up real soon.

15 MR. ESH: The reason --

16 MEMBER RYAN: In the next minute or so.

17 MR. ESH: Yes, okay. The reason why --

18 this is -- this table is actually 25 elements analyzed

19 for nine conditions probabilistically. There's

20 essentially 225 horsetail plots, is what we call in

21 our probabilistic analysis, that represent the

22 information in this table. So it's understandable

23 that it's a little hard to get your hands around.

24 MEMBER RYAN: Okay.

25 MR. ESH: The basis for our no dose limit
188

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1 for the second tier is we -- as I have talked about in

2 detail, we think they can put them in the -- better

3 put them in their proper context. We are better

4 aligned with long-term decisionmaking in other

5 programs, so you can argue that we're not aligned at

6 all, but at least it's stepping in the right

7 direction, and it's not inconsistent with past

8 Commission policy of how they do waste disposal

9 analysis.

10 And we can better align the impacts with

11 the uncertainties as opposed to -- because I think it

12 is reasonable to expect you should be able to

13 generate, with a proper amount of model support and

14 technical basis, that my range of impacts are maybe

15 one to 100. You can't say that it's 23.7 at year

16 20,000, but you should be able to say what band you're

17 in, whether it's -- I'm at a million millirem or one

18 millirem.

19 But it is impractical to think that you

20 are going to be able to say it's 23.7 definitively at

21 year 47,000, so that's why we think it's better

22 aligned with the uncertainties.

23 Now, we did develop guidance on this, and

24 we think it's risk-informed, performance-based. What

25 we basically say in our guidance is we allow people
189

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1 the flexibility, if you only have short-lived waste,

2 or you have low concentrations of long-lived waste,

3 just run the crank on your analysis and generate the

4 numbers and explain that. 

5 There is no additional regulatory burden

6 associated with it if you have short-lived waste or

7 low risk. The additional regulatory burden only comes

8 in when you have large concentrations of long-lived

9 waste. 

10 That is the approach that we're dictating

11 by this 20,000 period, which is a common metric for

12 all in the regulation, but then allowing for some

13 flexibility in how you -- what -- because in risk14 informed, performance-based regulation, it really

15 boils down to how much information you need to supply

16 for different things.

17 And what we're saying is for the low-risk

18 things you are not going to have to supply a lot of

19 information. For the high-risk situation, you are

20 going to have to supply a lot of risk. 

21 And then, the Subcommittee talked about

22 this Option 4 a little bit. This is just a backup

23 slide on it would be a three-tiered approach. It is

24 more complicated. We thought it would be difficult to

25 get that through stakeholders, so --
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1 MEMBER RYAN: Okay.

2 MR. ESH: So 15 seconds for discussion.

3 (Laughter.)

4 DW*: We've still got another whole

5 presentation.

6 MEMBER RYAN: Mr. Chair, I defer to

7 your --

8 CHAIRMAN ABDEL-KHALIK: We can give you

9 five minutes.

10 MR. CARRERA: I can wrap it up in five

11 minutes.

12 CHAIRMAN ABDEL-KHALIK: Thank you.

13 MR. CARRERA: Just a few slides. Okay.

14 Let's move on to happier thoughts here. We are going

15 to talk about stakeholder comments on the preliminary

16 proposed ruling which you are aware the NRC published

17 the Part 61 preliminary proposed rule language on

18 regulations.gov and solicited early public comments on

19 these documents.

20 We also held a public meeting on May 18th

21 as well to solicit public comments. And the public

22 comment period ended on June 18th, and the staff is in

23 the process of doing a review on these comments.

24 Next slide, please.

25 We received about 30 verbal comments from
191

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1 the May 18th public meeting, and 125 comments at the

2 end of the comment period on June 18th. And the

3 comments came from a diverse group of stakeholders,

4 public interest groups, industry, government

5 organizations, and these are, as Dave mentioned, just

6 as diverse as the organization that they represent.

7 This is just to give you a flavor of what

8 -- the types of comments that we received. You know,

9 as Dave mentioned, like, you know, a period of

10 performance -- how people feel about it, you know,

11 have a wide range of -- you know, some people approve,

12 some people disapprove, and there are others that are

13 in between that, you know, recommend maybe go to

14 10,000, 20,000, or somehow to taking a dose.

15 Dave covered the intruder assessment.

16 What are the comments? Same thing -- there is a wide

17 range.

18 Let's move on to the NRC Agreement State

19 compatibility recommendations. Some comments suggest

20 that we should recommend a strict compatibility level

21 to ensure that the -- there is a consistency in the

22 implementation of the regulation among the Agreement

23 States, while I would suggest that we should work with

24 the states, so that there would be no unintended

25 consequences.
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1 And we do have a representative from the

2 State of Texas who represents the Organization of

3 Agreement States and the CRCPD on the rulemaking team.

4 So, you see, this -- let me try to wrap this up. It's

5 a wide range of commenters and establishing a process

6 of really analyzing them. And we will continue for

7 the next several weeks to look at these comments with

8 a magnifying glass to determine the extent that these

9 comments will impact our rulemaking approach.

10 And that brings us to the path forward

11 through this rulemaking.

12 Next slide, please.

13 This is the path forward. Following

14 today's meeting, the staff will reevaluate the

15 rulemaking approach in light of the comments received

16 from you, the ACRS, as well as external stakeholders.

17 However, the staff will not prepare responses to the

18 comments received.

19 In August, the staff will come back and

20 brief the ACRS Subcommittee on the changes to the

21 rulemaking approach, as well as the guidance document.

22 I know, Dr. Ryan, you are especially interested in

23 that.

24 MEMBER RYAN: Yes.

25 MR. CARRERA: And at the same time, the
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1 staff would like to make known that we would request

2 a letter from the ACRS.

3 MEMBER RYAN: No problem.

4 (Laughter.)

5 Be happy to provide one.

6 MR. CARRERA: Thank you. And following

7 the September ACRS briefing and the letter, staff will

8 finalize the proposed rule document and guidance

9 document. And if the Commission approves, they will

10 make publicly available for comment, after which staff

11 will return to brief the ACRS Subcommittee, and the

12 subsequent full Committee, on the comments that we

13 received from the proposed rule.

14 So that's -- if you have any more

15 questions, please ask Dave.

16 (Laughter.)

17 MEMBER RYAN: Thank you, Andrew. And I

18 want to say a vote of appreciation to David for, you

19 know, having two hours of intense conversation. And

20 I think at some point the NRC should give you another

21 Ph.D. for all the hard work you have put in. 

22 And I want to thank your colleagues on the

23 Performance Assessment Team for all of the hard and

24 quality work they have done. So we really appreciate

25 your coming and talking in detail with us today. It's
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1 very helpful, I think, for some of the other members

2 to learn a little bit more about this and gain some

3 insights from the conversation. So thank you very

4 much.

5 MR. ESH: Thank you.

6 CHAIRMAN ABDEL-KHALIK: Thank you.

7 MEMBER RYAN: Mr. Chairman, back to you.

8 CHAIRMAN ABDEL-KHALIK: Thank you. At

9 this time, our schedule calls for us to take a

10 15-minute break. We are off the record for the day,

11 and we will reconvene at 10 after.

12 (Whereupon, at 3:55 p.m., the proceedings

13 in the foregoing matter went off the

14 record.)

15

16

17

18

19

20

21

22

23

24

25
Introduction to 

NRC Staff Review of 

NEDC-33173P, Supplement 2

“Analysis of Gamma Scan Data and Removal of 

Safety Limit Critical Power Ratio (SLMCPR) Margin”

Steve Philpott

NRR/DPR/PLPB
Interim Methods Process

• IMLTR SE imposes 24 limitations for 

EPU and MELLLA+ applications

• GE-Hitachi Nuclear Energy (GEH, 

previously GE) has committed to 

provide additional data to address 

several limitations as supplements to 

the IMLTR

2
IMLTR Supplement 2 Overview

• IMLTR SE Limitation 4: +0.02 adder to 

cycle-specific SLMCPR for EPU

• IMLTR SE Limitation 5: +0.03 adder to 

cycle-specific SLMCPR for MELLLA+

• Supplement 2 requests removal of 

Limitations 4 and 5

• No other changes in SE Limitations

3
Final Methods Roadmap

• Supplement 2 (SE Appendix I)

GEH commitment to qualify the nuclear 

methods (MFN 06-434)

Pin and bundle gamma scan data 

submitted August 14, 2009

Supplement 2 is in 3 parts and aims to 

remove the SLMCPR adders

4
Supplement 2: Gamma Scan Data

• Bundle gamma scan data from Cofrentes

• Pin-wise gamma scan data from FitzPatrick

• To address additional margins for power 

distribution uncertainties for EPU / thermal 

margin for MELLLA+

• Does not request removal or modification of 

any IMLTR limitations other than 

Limitations 4 and 5

5
•BACKUP SLIDES
Background

• Jan 2002 - MELLLA+ LTR submitted

• Sep 2003 - VYNPS EPU LAR submitted

• Jun 2004 - BFN1 EPU LAR submitted

• Nov 2005 - M+LTR Rev. 2 submitted

• Feb 2006 - Interim Methods LTR submitted

• Sep 2007 - M+LTR approved

• Jan 2008 - IMLTR SE issued 1/08

7
Final Methods Roadmap

• GSTRM Part 21 (SE Appendix F)

– Staff audited revised GE14 compliance 

documents to address findings related 

to the GSTRM Part 21 evaluation.

• Outstanding methods-related RAI 

responses (SE Appendix G)

– GEH committed to address outstanding 

methods RAIs

8
Final Methods Roadmap

• Supplement 1 (SE Appendix H)

– GEH commitment to qualify the voidquality correlation (MFN 06-435)

– Pressure drop data and COBRAG 

analyses – submitted in April 2010

– Supplement 1 data provided with intent 

to remove the OLMCPR 0.01 adder

9
Final Methods Roadmap

• IMLTR RAI 9 (SE Appendix J)

– GEH committed to provide plenum 

fission gas and fuel exposure gamma 

scans (MFN 06-481)

– To be submitted as a supplement to the 

PRIME LTRs

– NRC Staff will examine to confirm the 

commitment has been satisfied

10
Final Methods Roadmap

• Supplement 3 (SE Appendix K)

– IMLTR restricted to GE14 and earlier GE fuel

– Supplement 3 extended approval to GNF2 fuel

• Supplement 4 (SE Appendix L)

– GEH committed to migrate to PRIME T-M 

methods (MFN 09-143)

– Supplement 4 describes a process for 

migration

– SE Appendix L will be supplemented by an 

NRC audit of the final implementation

11
Final Methods Roadmap

• IMLTR SE Limitation 23 (SE Appendix M)

– MELLLA+ eigenvalue tracking data for first 

MELLLA+ plant

– Monticello MELLLA+ LAR submitted Jan 2010 

(licensee intends to comply with this limitation)

• IMLTR SE Limitation 13 (SE Appendix N)

– Supplement required for application to 

gadolinia loading greater than 10 weight 

percent.

12
NRC Staff Conclusions for 

NEDC-33173P, Supplement 2

“Analysis of Gamma Scan Data and Removal of 

Safety Limit Critical Power Ratio (SLMCPR) Margin”

Dr. Peter Yarsky

RES/DSA/RSAB
IMLTR Supplement 2 Overview

• IMLTR SE Limitation 4: +0.02 adder to 

cycle-specific SLMCPR for EPU

• IMLTR SE Limitation 5: +0.03 adder to 

cycle-specific SLMCPR for MELLLA+

• Supplement 2 requests removal of 

Limitations 4 and 5

• No other changes in SE Limitations

2
Review Basis and Approach

• NRC staff reviewed:

Gamma scan data collection and processing

Gamma scan results

TIP data and comparisons to expanded EPU 

database

Comparison of key operating parameters

LPRM calibration uncertainty

Applicability to MELLLA+ operation

3
Conclusions

• Limitations 4 and 5 of the NRC staff’s SE 

for the IMLTR impose adders to the cyclespecific SLMCPR values:

– +0.02 for EPU operation

– +0.03 for MELLLA+ operation. 

• GEH requested that the NRC review and 

approve the NEDC-33173P, Supplement 2, 

Parts 1-3, and Revision 2 - to remove 

Limitations 4 and 5.

4
Conclusions

• Based on review of Supplement 2 and 

Revision 2, the NRC staff concurs with GEH's 

request with one exception:

Limitation 5 stipulates that for operation at 

MELLLA+, including operation at the EPU power 

levels at the achievable core flow state-point, a 

0.03 value shall be added to the cycle-specific 

SLMCPR value. The added value of 0.03 will 

now be reduce to 0.01. This adder may be 

removed if GEH submits MELLLA+ operation 

data, subject to NRC staff review and approval.

5
•BACKUP SLIDES
Comments on Mechanical 

Behavior of Ballooned and 

Ruptured Cladding

Ken Yueh

Senior Project Manager

ACRS Meeting

July 13, 2011
© 2011 Electric Power Research Institute, Inc. All rights reserved. 2

Feedback

• The industry is supportive of the NRC’s research efforts on 

the mechanical behavior of the ballooned and ruptured 

cladding region

• The test results reported in ML111370032 are consistent 

with other international test results

– Quench survivability with and without restraint

– Mechanical strength and impact resistance are not as 

strongly dependent on hydrogen concentration in the 

hydrogen range of interest

– International research efforts are focused on generating data 

to support alternative acceptance criteria not tied to ductility
© 2011 Electric Power Research Institute, Inc. All rights reserved. 3

Published Test Results Review

10

100

1000

10000

5.5 6.0 6.5 7.0 7.5 8.0 8.5 9.0

104/T (1/K)

Time at Oxidation Temperature (s)

Quench Failure Data

Failed at 0.03J impact

Survived 0.03J but failed up to a 0.15J Impact

Survived 0.15J but failed at 0.3J Impact

Survived 0.3 J Impact, Hydrogen < 300 ppm

Survived 0.3 J Impact, Hydrogen 300-600 ppm

Survived 0.3 J Impact, Hydrogen > 600 ppm

17% CP-ECR for 0.57 mm cladding

* Chung and Kassner, NUREG/CR-1344

10

100

1000

10000

5.5 6.0 6.5 7.0 7.5 8.0 8.5 9.0

104/T (1/K)

Time at Oxidation Temperature (s)

Survived 0.3J Impact

Survived 0.15J but failed at 0.3J Impact

Survived 0.03J but failed up to a 0.15J Impact

Failed at 0.03J impact

Quench Failure Data

17% CP-ECR for 0.57 mm cladding

No apparent hydrogen 

dependence

17% limit has a lot of 

margin to quench failure

• Quench survivability and impact test results
© 2011 Electric Power Research Institute, Inc. All rights reserved. 4

Published Test Results Review

• Large margin to quench failure under axial restraint, 

hydrogen pre-charged and irradiated high burnup cladding

* Nagase, 2010 JAEA Fuel Safety Research Meeting

MFI-2 & ZRT-2: no restraint

MDA-2R: 530N

ZIR-2R: 518N

ZRT-1 & ZIR-3R: 519N

JAEA Conclusion

“Fracture boundary is not 

reduced significantly by high 

burn-up and use of new 

alloys in the examined 

burnup level, thought it may 

be somewhat reduced with 

pre-hydriding as observed 

with unirradiated Zircaloy-4”
© 2011 Electric Power Research Institute, Inc. All rights reserved. 5

Feedback

• The application of the test results is not consistent with the 

principles of the proposed rule, which is based on the 

maintenance of ductility

– Seems like an “exemption” is granted for the ballooned and 

ruptured region

– Recommend the “ductility” requirement be placed in a lower 

level regulatory guide

• If the acceptance of the ballooned and ruptured region 

condition can be made on the basis of results documented 

in ML111370032, then the same standard should be 

allowed for the balance of the fuel rod
© 2011 Electric Power Research Institute, Inc. All rights reserved. 6

Together...Shaping the Future of Electricity
1

Overview of the 10 CFR 50.46c Rulemaking

July 13, 2011

Tara Inverso

Division of Policy and Rulemaking

Office of Nuclear Reactor Regulation
Meeting Purpose

• Present the expanded regulatory 

basis on regulatory treatment of the 

balloon region to ACRS

2
Meeting Agenda

1. Overview of 50.46c rulemaking activities

2. Additional research into mechanical behavior 

of the balloon

3. Industry remarks

4. ACRS discussion

3
Rulemaking Purpose

• Revise ECCS acceptance criteria to 

reflect recent research findings

• SECY-02-0057

– Replace prescriptive analytical 

requirements with performance-based 

requirements

– Expand applicability to all fuel designs 

and cladding materials

• Address concerns raised in two 

PRMs: PRM-50-71 and PRM-50-84

4
Recent Developments

• Draft regulatory guidance developed

– Presented to ACRS on May 10, 2011 

(sub-committee) and June 8, 2011 (full 

committee)

• Staff continues to evaluate results of 

fuel fragmentation/dispersion 

research

• “Mechanical Behavior of 

Ballooned and Ruptured Cladding”

5
Rulemaking Schedule

• Anticipated ACRS Meetings on 

Proposed Rule:

– Sub-committee: December 2011

– Full committee: February 2012

• Proposed Rule Due to the Executive 

Director for Operations:

– February 29, 2012

6
Questions?

Tara Inverso, Project Manager

301-415-1024; tara.inverso@nrc.gov

7
1

10 CFR 50.46c ECCS Rulemaking: 

Mechanical Behavior of the Balloon

Advisory Committee on Reactor Safeguards

July 13, 2011

Michelle Flanagan

Michelle.Flanagan@nrc.gov

Division of Systems Analysis

Office of Nuclear Regulatory Research
2

Overview

Contents of “Mechanical Behavior of Ballooned and 

Ruptured Cladding”: 

• Begins with a review of the regulatory history of the 

balloon region

• Presents the results of the NRC’s integral LOCA 

research program

• Supports the treatment of the ballooned region 

within the rulemaking to revise 10 CFR 50.46(b). 
3

Regulatory History

• The core remains amenable to cooling. 

(Coolable geometry)

• Decay heat is removed for the extended 

period of time required by the long-lived 

radioactivity remaining in the core (Longterm cooling)

10CFR 50.46 Acceptance criteria for 

emergency core cooling systems for lightwater nuclear power reactors.

Appendix A of 10CFR Part 50, General 

Design Criteria 35 Emergency Core Cooling

Regulation requires that an emergency core 

cooling system is available to ensure that if a 

loss-of-coolant accident took place:
4

• The calculated maximum fuel element cladding temperature 

shall not exceed 2200o F.

• The calculated total oxidation of the cladding shall nowhere 

exceed 0.17 times the total cladding thickness before 

oxidation. 

§ 50.46 Acceptance criteria for emergency core 

cooling systems for light-water nuclear power 

reactors.

Commission hearings in the 1970’s established that coolable 

geometry could be maintained if the fuel cladding remained 

ductile.

Therefore criteria were established, largely based on ring 

compression data, to ensure ductility, and these criteria are 

specified in the rule. The criteria state:

Completed Investigation: Are these criteria still appropriate for 

high burnup cladding?

Finding: Completed embrittlement program indicated the 

oxidation criterion is not sufficient for high burnup cladding

Regulatory History
0

2

4

6

8

10

12

14

16

18

20

0 100 200 300 400 500 600 700 800

Embrittlement Oxidation Limit (% ECR)

Pre-Transient Hydrogen Content (wppm)

10 CFR 50.46(b)

Proposed 

Limit

Research Findings

5
6

§ 50.46, “Acceptance criteria for emergency core 

cooling systems for light-water nuclear power 

reactors”

Maximum cladding oxidation is defined within the regulations:

The calculated total oxidation of the cladding shall nowhere exceed 0.17 times the total 

cladding thickness before oxidation. As used in this subparagraph total oxidation means the 

total thickness of cladding metal that would be locally converted to oxide if all the oxygen 

absorbed by and reacted with the cladding locally were converted to stoichiometric

zirconium dioxide. If cladding rupture is calculated to occur, the inside surfaces of the 

cladding shall be included in the oxidation, beginning at the calculated time of rupture. 

Cladding thickness before oxidation means the radial distance from inside to outside the 

cladding, after any calculated rupture or swelling has occurred but before significant 

oxidation. Where the calculated conditions of transient pressure and temperature lead 

to a prediction of cladding swelling, with or without cladding rupture, the unoxidized

cladding thickness shall be defined as the cladding cross-sectional area, taken at a 

horizontal plane at the elevation of the rupture, if it occurs, or at the elevation of the 

highest cladding temperature if no rupture is calculated to occur, divided by the average 

circumference at that elevation. For ruptured cladding the circumference does not include 

the rupture opening.

Is this approach still valid for the balloon node, with the new 

understanding of the effect of hydrogen? 

Existing treatment of the Balloon
7

Balloon Region Phenomenon
8

Proposed Treatment of the Balloon 

Region in RIL-0801

Research Information Letter-0801, Technical Basis for 

Revision of Embrittlement Criteria in 10 CFR 50.46

“Finally, no criteria have been found that would ensure 

ductility in the cladding balloon. However, loss of 

ductility in this short portion of a fuel rod should not lead 

to an uncoolable geometry as long as the amount of 

oxidation in the ballooned region remains limited in the 

current manner.” 
9

Sections of pressurized, as-received, 

prehydrided and irradiated cladding, 

approximately 300 mm in length, were 

ramped from 300oC at a rate of 5oC/sec. 

They were pressurized to induce 

ballooning and burst and to target balloon 

sizes within the range of 30% - 70% 

strain. They were oxidized in steam to 

target oxidation levels (ECR), with 

consideration of the strain and hydrogen 

content. 

The sections of cladding underwent 

ballooning, burst and oxidation in a test 

train shown to the left. 

Investigation on Balloon 

Mechanical Behavior
10

Bend tests were used to 

evaluate the balloon 

mechanical behavior in a 

mechanical test that 

applies a uniform 

bending moment to the 

ballooned region. The 

axial location and nature of 

fracture was recorded. The 

observations of bend tests 

on irradiated material were 

compared to bend test 

results on as-received and 

pre-hydrided ballooned and 

burst integral samples run 

at ANL. 

Investigation on Balloon 

Mechanical Behavior
11

1. Maximum plastic displacement (measure of ductility)

2. Maximum applied energy (measure of toughness)

3. Maximum bending moment (measure of strength)

4. Failure location 

Bend tests provide a variety of quantitative information, and 

are relatively sensitive to changing material properties

Force x moment arm

Investigation on Balloon 

Mechanical Behavior
12

Investigate influence of:

Oxidation

Irradiation

Balloon size

Bend test temperature

Hydrogen content



ANL

Studsvik









Investigation on Balloon 

Mechanical Behavior
Results – As-Fabricated

Test

ID

OCZL#

Fill

Pressure,

psig

Rupture

Strain, %

(TR, °C) 

CPECR

%

Quench

at 

800°C

Stress in

Rupture

Node

Failure

Location

Maximum

Bending

Moment

N•m

Maximum

Energy

J

Plastic

Displace.

mm

8 600 21

(845±25)

0 No Maximum

tension

No

cracking

20.9 >8.4 >7.7

9 400 33

(875±15)

0 No Maximum

tension

No

cracking

20.6 >8.3 >7.7

10 1600 69

(715±10)

0 No Maximum

tension

No

cracking

19.5 >7.7 >7.1

12 1000 32

(805±20)

14 No Maximum

compression

-40 mm

+33 mm

10.5 0.78 0

13 1200 41

(741±15)

14 No Maximum

tension

Rupture

opening

8.8 0.58 0

14 1200 47

(735±6)

18 Yes Maximum

tension

Rupture

opening

5.7 0.24 0

15 1200 51

(755±23)

18 Yes Maximum

compression

Cracking;

no failure

8.9 >2.3 >13

17 1200 49

(750±17)

13 Yes Maximum

tension

Rupture

opening

8.4 0.71 >0.5

18 1200 43

(748±4)

12 Yes Maximum

tension

Rupture

opening

13.5 1.29 0

19 600 24

(840±12)

17 Yes Maximum

tension

+23 mm

-23 mm

5.7 0.23 0

21 600 27

(850±10)

10 Yes Maximum

tension

+33 mm

-29 mm

13.8 1.17 0

22a 600 22

(837±12)

11 Yes Maximum

tension

+25 mm

-27 mm

11.1 0.83 0

25a 1200 42

(757±21)

16 Yes Maximum

tension

-26 mm

+26 mm

8.3 0.50 0

29a 1200 49

(746±19)

17 Yes Maximum

tension

Rupture 

opening

4.7 0.40 >8.5

32a,b 1200 49

(748±8)

17 Yes Maximum

tension

Rupture

opening

6.7 0.26 0

a Displacement rate lowered to 1 mm/s to get better agreement between bend and ring-compression tests for the maximum elastic strain rate.

b 4 -PBT conducted at 30°C. 13
Results – As-Fabricated

Bending Moment

For ECR > 10%; Mmax = 13.96 – 1.090 (CP-ECR – 10%), N•m

0

2

4

6

8

10

12

14

16

18

20

22

0 5 10 15 20

CP-ECR (%)

Maximum Bending Moment (N•m) 

ΔC/Ci ≥ 40%; 135°C Tests

ΔC/Ci ≤ 33%; 135°C Tests

ΔC/Ci ≥ 40%, 30°C Test

Fit to 135°C Data

Maximum bending moment as a function of maximum oxidation level (CP-ECR) for postLOCA samples subjected to 4-PBTs with the rupture region in tension for all tests but one. 

Bend tests were performed at 135°C and 2 or 1 mm/s to 14-mm maximum displacement. 

One bend test was performed at 30°C and 1 mm/s.

14
Results – As-Fabricated

Failure Location

(a) Hydrogen-content profile

b) Measured values at failure locations

(c) Low-magnification image of severed cross section at -24 mm

(a) Hydrogen-content profile

(b) Failure location

(c) Low-magnification image of severed cross section

15
Results – As-Fabricated 

Failure Energy

For ECR > 10%; Emax = 1.22 – 0.121 (CP-ECR – 10%), J

0

1

2

3

4

5

6

7

8

9

10

0 5 10 15 20

CP-ECR (%)

Maximum Energy (J) 

ΔC/Ci ≥ 40%; 135°C Tests

ΔC/Ci ≤ 33%; 135°C Tests

ΔC/Ci ≥ 40%, 30°C Test

Fit to 135°C Data

Figure 4. Maximum (for 0% CP-ECR) and failure (for ≥10% CP-ECR) energy as a 

function of oxidation level (CP-ECR) for post-LOCA samples subjected to four-point 

bending with the rupture region in tension for all tests but one. Bend tests were 

performed at 135°C and 2 or 1 mm/s to 14-mm maximum displacement. One bend 

test was conducted at 30°C and 1 mm/s.

16
02468

10

12

14

16

18

20

0 100 200 300 400 500 600 700 800

Embrittlement Oxidation Limit (% ECR)

Pre-Transient Hydrogen Content (wppm)

Investigation on Balloon 

Mechanical Behavior

17

Irradiated Testing at Studsvik
Results – Irradiated Tests

189 191 192 193

Comments Ramp to rutpure 

test

Ramp to PCT, 

held for 25s at 

PCT

Ramp to PCT, 

held for 5s at 

PCT

Ramp to PCT, 

held for 85s at 

PCT

Burnup ≈ 72 GWD/MTU ≈ 71 GWD/MTU ≈ 72 GWD/MTU ≈ 72 GWD/MTU

PCT 950 ± 20°C 1185 ± 20°C 1185 ± 20°C 1185 ± 20°C

Measured Strain 48% 50% 56% 50%

Calculated ECR ≈ 0% 13% 11% 17%

Fill Pressure 110 110 82 82

Burst Pressure 113 104 77 77

Burst Temperaure 700 680 700 728

Rupture Width 10.5 17.5 9.0 13.8

Rupture Length 23.9 21.6 22.7 17.8

(a) (b) (c) (d)

A close up of the rupture opening after the transient on rod segment from test (a) 189 (b) 191 (c) 192 and (d) 193 18
Results – Comparing AF, PH & 

Irradiated data

Maximum bending moment as a function of oxidation level for post-LOCA-oxidation samples subjected to 4PBTs at 1-2 mm/s and 

either 135°C or RT (30°C). For samples at 0% CP-ECR, which did not fail, values are plotted for 14-mm displacement. The trend line 

is a best fit to Argonne 4PBT data at 135°C.

* NOTE: The values for pre-hydrided material have become available since the DRAFT “Mechanical Behavior of Ballooned and 

Ruptured Cladding” report was transmitted to ACRS in support of this briefing. 19

0

2

4

6

8

10

12

14

16

18

20

22

24

26

28

30

32

34

0 5 10 15 20

Maximum Bending Moment (N•m) 

CP-ECR (%)

AF; ΔC/Ci ≥ 40%; 135°C Tests

AF; ΔC/Ci ≤ 33%; 135°C Tests

AF; ΔC/Ci ≥ 40%, 30°C Test

HB; ZIRLO, ΔC/Ci ≥ 39%, 30°C Test

PH; 400-wppm; ΔC/Ci ≥ 40%, 135°C Test *

PH; 670-wppm; ΔC/Ci ≥ 40%, 135°C Test *
Results – Comparing AF, PH & 

Irradiated data

Maximum energy as a function of oxidation level for post-LOCA-oxidation samples subjected to 4PBTs at 1-2 mm/s and either 135°C 

or RT (30°C). For samples at 0% CP-ECR, which did not fail, maximum energies through 14-mm displacement are plotted. For 

samples with >10% CP-ECR, data points represent failure energy. The trend line is a best fit to Argonne 4PBT data at 135°C. 

* NOTE: The values for pre-hydrided material have become available since the DRAFT “Mechanical Behavior of Ballooned and 

Ruptured Cladding” report was transmitted to ACRS in support of this briefing. 20

0

2

4

6

8

10

0 5 10 15 20

Maximum Energy (J) 

CP-ECR (%)

AF; ΔC/Ci ≥ 40%; 135°C Tests

AF; ΔC/Ci ≤ 33%; 135°C Tests

AF; ΔC/Ci ≥ 40%, 30°C Test

Fit to 135°C Data

HB; ZIRLO, ΔC/Ci ≥ 39%, 30°C Test

PH; 400-wppm; ΔC/Ci ≥ 40%, 135°C Test *

PH; 670-wppm; ΔC/Ci ≥ 40%, 135°C Test *
Program Conclusions

• All samples survived quench

• The values of bending moment and failure energy have been shown 

to decrease with increasing oxidation, even through a wide range of 

values for balloon strain

• Even though very high values of hydrogen content were observed 

within the balloon region for the as-fabricated samples, no matter 

where the failure was observed, the residual bending moment 

remained a function of the oxidation

• The values of bending moment and failure energy reveal a hydrogen 

effect on the mechanical behavior of the balloon region that should 

be accounted for

• When the new proposed hydrogen-based criteria is applied in the 

rupture region, mechanical properties in this region are maintained to 

at least that of fresh cladding

21
Addressed in three aspects

• Treatment of the ballooned region within the rulemaking 

to revise the embrittlement criteria in 10 CFR 50.46

• Extrapolation of research findings to new cladding alloys 

and lower oxidation temperatures

• Alternate performance metrics for the ballooned and 

ruptured region of a fuel rod 

22

Program Conclusions 

within the Regulatory Context
Program Conclusions

Within the Regulatory Context: Treatment of 

the Ballooned Region within the Rulemaking 

To Revise 10 CFR 50.46(b) 

23

The time-at-temperature limit developed based on ringcompression data to limit oxidation should be applied uniformly 

to the entire rod, with the provisions for the balloon outlined in 

the existing rule to use the average wall thickness in the rupture 

region to calculate the CP-ECR.
• Embrittlement limits developed for new cladding alloys or at lower 

oxidation temperatures based on RCTs may be applied uniformly to 

the entire rod, with the provisions for the balloon outlined in the 

existing rule to use the average wall thickness in the rupture region to 

calculate the CP-ECR.

• Results did not reveal any reason that materials which demonstrate 

improved embrittlement performance in RCTs should not apply 

measured improvement in the balloon region

– Yield properties and fuel rod dimensions considered in the conclusion

24

Program Conclusions

Within the Regulatory Context: Extrapolation of 

Research Findings to New Cladding Alloys and 

Lower Oxidation Temperatures 
• There has been longstanding discussion of alternate metrics for fuel 

rod performance under LOCA conditions within the international 

community. 

• Alternate approaches rely on detailed knowledge of LOCA loads or 

complex experimental and modeling research programs. 

• The state-of-the art does not support regulatory positions based on 

these proposals in the near term and therefore, pursuing more 

complex performance metrics for ballooned and ruptured regions is 

not recommended at this time.

25

Program Conclusions

Within the Regulatory Context: Alternate 

Performance Metrics for the Ballooned and 

Ruptured Region of a Fuel Rod 
Proposed Update to RIL-0801

26

Research Information Letter-0801, Technical Basis for Revision 

of Embrittlement Criteria in 10 CFR 50.46

Finally, no criteria have been found that would ensure ductility 

in the cladding balloon. However, loss of ductility in this short 

portion of a fuel rod should not lead to an uncoolable geometry 

as long as the amount of oxidation in the ballooned region 

remains limited in the current manner. Bending moment and 

failure energy have been measured using the 4-PBT for asreceived, pre-hydrided and irradiated samples to determine the 

resistance to fracturing and fragmentation of ballooned 

cladding during a LOCA. Values comparable to those 

determined for as-fabricated cladding at 17% CP-ECR have 

been found when oxidation is limited in accordance with 

embrittlement threshold shown in Figure 1.
Conclusion

• Completed integral LOCA test program has generated 

new data and understanding of the mechanical behavior 

of ballooned and ruptured fuel rods

• Results indicate that limiting oxidation in the balloon 

region continues to be appropriate

• Results indicate that applying the hydrogen-based 

embrittlement limit in the balloon region preserves 

mechanical behavior to that of as-fabricated rods at 17%

• A technical basis document has been written to 

supplement the treatment of the balloon within the 

proposed rulemaking

• Updates to RIL-0801 have been proposed which 

incorporate the findings of the recent research

27
10 CFR Part 61: 

Preliminary Proposed Rule Language

Andrew Carrera

Division of Intergovernmental Liaison and Rulemaking

Office of Federal and State Materials and Environmental 

Management Programs

Andrew.Carrera@nrc.gov, (301) 415-1078

585th Meeting of the Advisory Committee on 

Reactor Safeguards

July 13, 2011
Purpose of rulemaking

• Emerging regulatory issues in LLW disposal

– Discrepancies from original 10 CFR Part 61 assumptions

• Disposal sites are currently faced with disposing of waste types that 

were not considered at that time

– Uranium enrichment

• More than 1 million metric tons of depleted uranium (DU) require 

disposal

– Industry innovation to address Class B & C LLW

• Industry contemplating large-scale blending

2
3

Commission Directions

• SRM-SECY-08-0147:

– Require site-specific analysis for disposal of large quantities of DU 

– Meet performance objectives

– Specify criteria needed for analysis

– Develop supporting guidance

• SRM-SECY-10-0043:

– Incorporate blending issue into the existing rulemaking for DU

DU + Blending
Proposed Amendments to 

Part 61 Regulations

• Site-Specific Analyses: 

1. Performance assessment — to demonstrate compliance with the protection of 

the general population from releases of radioactivity performance objective 

(§ 61.41)

2. Intruder assessment — to demonstrate compliance with the protection of 

inadvertent intruders performance objective (§ 61.42)

3. Long-Term analysis — to demonstrate how the design of the facility considers 

the potential long-term radiological impacts (§ 61.13 (e))

4. Update analyses at facility closure — to be updated and included with any 

application to amend the license for closure (§ 61.13 (e))

4
Proposed Amendments to 

Part 61 Regulations 

(continued)

• Other Supporting Changes:

1. New definitions, concepts, and long-term analysis

2. Use of total effective dose equivalent (TEDE)

• Waste-Stream Neutral:

1. Site-specific-analyses requirements would apply to all wastes

5
Site-Specific Analyses: 

Performance Assessment

• § 61.41 Protection of the general population from 

releases of radioactivity.

Revised requirements:

§ 61.41(a)—Revised to include TEDE.

§ 61.41(b)—Added requirement to demonstrate compliance 

with a performance assessment for 20,000 years.

6
Site-Specific Analyses: 

Intruder Assessment

• § 61.42 Protection of inadvertent intruders.

Revised requirements:

§ 61.42(a)—Added annual dose of 500 mrem TEDE.

§ 61.42(b)—Added requirement to demonstrate compliance 

with a intruder assessment for 20,000 years.

7
Site-Specific Analyses:

Long-Term Analysis

• § 61.13 Technical analyses.

New requirements:

§ 61.13(e)(1)—Discuss how the design of the facility 

considers the potential long-term radiological impacts, consistent 

with available data and current scientific understanding. 

§ 61.13(e)(2)—Calculate the peak annual dose that would 

occur 20,000 or more years after site closure. No dose limit 

applies to the results of these analyses.

8
Site-Specific Analyses:

Updated Analyses

• § 61.28 Contents of application for closure.

New requirement:

§ 61.28(a)(2)—Submit revised analyses for § 61.13 using the 

details of the final closure plan and waste inventory.

• § 61.52 Land disposal facility operation and disposal 

site closure.

New requirement:

§ 61.52(a)(12)—Dispose of waste consistent with the 

description provided in § 61.12(f), and the technical analyses 

required by § 61.13.

9
Other Supporting 

Changes

• § 61.2 Definitions.

New definitions: 

intruder assessment, long-lived waste, and performance 

assessment.

• § 61.7 Concepts.

New concepts: 

intruder assessment, performance assessment, and long-term 

analysis.

10
10 CFR Part 61: 

Stakeholder Comments on the Preliminary 

Proposed Rule Language

Andrew Carrera

Division of Intergovernmental Liaison and Rulemaking

Office of Federal and State Materials and Environmental 

Management Programs

Andrew.Carrera@nrc.gov, (301) 415-1078

585th Meeting of the Advisory Committee on 

Reactor Safeguards

July 13, 2011
Stakeholder Comments 

• May 18th Public Meeting (~ 30 specific comments, 

suggestions, and recommendations received)

• 15 Comment Letters (~125 specific comments, 

suggestions, and recommendations)

• Diverse Stakeholders (public interest groups, industry, 

Federal and States government organizations)

2
Stakeholder Comments 

(continued)

• Near-Surface Inappropriate for Disposal of DU

• 20,000-year Period of Performance

• Intruder Assessment Requirement

• NRC/Agreement State Compatibility Recommendations

• Guidance v.s Rule

• Rulemaking Oversteps SRM-SECY-08-1047

• Other

3
Path Forward

• Following today’s meeting, staff will re-evaluate rulemaking 

approach in light of comments received from ACRS and external 

stakeholders

• In August, staff will brief ACRS Subcommittee on any changes to 

rulemaking approach, and request letter from ACRS following 

September Full Committee meeting

• In September, staff will brief ACRS full committee on any changes to 

rulemaking approach

• Following September ACRS briefing and ACRS letter, staff will 

finalize proposed rule documents

• After Proposed Rule (and Guidance) is made publicly available 

for comment, staff will return for a briefing of the 

ACRS Subcommittee

4
1

10 CFR Part 61:

Technical Issues for the Low-Level

Waste Rulemaking

David W. Esh

Division of Waste Management and 

Environmental Protection

Office of Federal and State Materials and Environmental 

Management Programs

David.Esh@nrc.gov, (301) 415-6705

585th Meeting of the Advisory Committee on 

Reactor Safeguards

July 13, 2011
2

Main Topics

• Intruder Assessment

• Period of Performance
3

Intruder Assessment
4

• Intruder assessment has three parts: waste classification 

and segregation, intruder barriers, and intruder dose 

assessment.

• New requirement for an intruder dose assessment.

• Necessary because the Commission directed the staff 

not to alter the waste classification system.

• Waste classified under 61.55(a)(6) could represent an 

unanalyzed condition from an intruder protection 

perspective.

Intruder Assessment
5

Intruder Assessment

• Regulatory construct.

• Intruder assessment is supported by a variety of groups 

(IAEA, ICRP, NCRP).

• Evaluate potential exposure of inadvertent intruders after 

institutional control period (100 years).

• Dose limit of 500 mrem TEDE reflects NRC belief that 

exposures are unlikely, albeit possible, and impacts will 

be limited to a few individuals.

• Reasonably foreseeable land use scenarios, impacted 

by timeframe and change in natural site conditions.
6

Intruder Assessment

Intruder assessment is an analysis that:

(1) Assumes that an inadvertent intruder occupies the site at any 

time during the compliance period after institutional controls are 

removed and engages in activities (e.g., agriculture, dwelling 

construction, and resource exploration) that might unknowingly expose 

the inadvertent intruder to radiation from the waste; 

(2) Examines the capabilities of intruder barriers to inhibit contact 

with the waste by an inadvertent intruder or to limit the inadvertent 

intruder’s exposure to radiation; and

(3) Estimates the potential annual total effective dose equivalent, 

considering associated uncertainties, to an inadvertent intruder 

engaging in activities that might unknowingly expose the inadvertent 

intruder to radiation from the waste.
7

Period of Performance
8

Background

• Period of performance is one of many important 

elements in the safety evaluation of low-level waste 

(LLW) disposal.

• Different approaches are used within the US and 

internationally for LLW.

• Diverse views among stakeholders.
9

NRC Background

• The Advisory Committee on Nuclear Waste (ACNW) 

commented on the period of performance on numerous 

occasions (since 1994).

• ACNW communicated basic principles (see next slide).

• Commission direction (SRM-96-103).

• NUREG-1573: Performance Assessment Working 

Group (PAWG) recommended 10,000 years with longerterm impacts in site environmental assessment.
10

ACNW Principles*

• Two tiers:

- No less than time for more mobile radionuclides to 

produce peak dose. 

- No longer than a time period over which scientific 

extrapolations can be convincingly made. 

- If the disposal system fails to meet the standard during 

the specified time period, ameliorating actions should be 

required or the site should be rejected. 

* from Pomeroy 1997

Consider site-specific characteristics
11

ACNW Principles*

- Evaluate robustness of the facility over the range of 

external processes and events that may affect the 

performance of the facility over long time periods. 

- This evaluation also will ensure that no significant 

changes in the dose from the disposal site will occur.

- Estimates of the peak dose from the facility beyond the 

time of compliance are qualitatively compared with the 

dose standard. 

* from Pomeroy 1997
12

General Objectives

• Provide protection to present and future 

generations

• Consider uncertainties

• Communicate long-term impacts

• Facilitate decision making
13

Period of Performance 

Selection Process

• Literature review:

- Characteristics of waste

- Analysis framework

- Uncertainties (societal, natural, engineering, 

technology)

- Socioeconomic considerations 

(transgenerational equity, discounting)
14

Waste Characteristics

0

20,000

40,000

60,000

80,000

100,000

120,000

140,000

160,000

0 200,000 400,000 600,000 800,000 1,000,000

Time (yr)

Ra-226 (pCi/g)

Assumptions:

No losses of material

Pure depleted uranium (100 wt.%)

50% disposal packing efficiency

10,000 years

? ?

This 99% of the waste does 

not cause risk from disposal
15

Waste Characteristics - HLW

From NUREG-1538
16

LLW Inventory Analysis –

Rulemaking Context

• Look at actual inventories disposed (use DOE MIMS 

database).

• Estimate the reduction factor needed to reduce the 

waste concentration to a groundwater concentration that 

would produce 25 mrem TEDE.

• Performance assessment is the process to verify that 

the necessary reductions will be achieved (sorption, 

solubility, dispersion, dilution).

• The next two slides are not PA results.
17

LLW Inventory Analysis

1.E-03

1.E-02

1.E-01

1.E+00

1.E+01

1.E+02

1.E+03

1.E+04

1.E+05

1.E+06

1.E+07

1.E+08

1.E+09

1.E+00 1.E+02 1.E+04 1.E+06 1.E+08 1.E+10

Reduction Factor to achieve 25 mrem

Half life (yr)

Barnwell

Clive

Richland

Beatty

Sr90

Large

Quantities

DU

U238 Th232

Increasing

Challenge

Blended

Sr90
18

1.E-03

1.E-02

1.E-01

1.E+00

1.E+01

1.E+02

1.E+03

1.E+04

1.E+05

1.E+06

1.E+07

1.E+08

1.E+09

1.E+00 1.E+02 1.E+04 1.E+06 1.E+08 1.E+10

Reduction Factor to achieve 25 mrem

Half life (yr)

Base

Geochem-mod

Sr90 Large

Quantities

DU

U238

Th232

Increasing

Challenge

Blended

Sr90

LLW Inventory Analysis
19

Uncertainty
20

Options Considered

1) No Change

2) Peak Dose

3) Regulatory Precedent (two tiers)

4) Uncertainty Informed Approach – three tiers, 

Compliance, Assessment, Performance (CAP)

5) Industrial Metals
21

• A compliance period of no less than 20,000 years, with a peak 

annual dose limit of 25 mrem TEDE.

•A requirement to perform a calculation of peak annual dose that 

occurs after 20,000 years as an indicator of long-term facility 

performance. No dose limit would apply to this analysis.

•A requirement to provide analyses that demonstrate how the 

facility was designed to mitigate long-term impacts.

•Associated changes to the regulations to highlight the 

uncertainties associated with disposing of long-lived waste and 

that limitations on the disposal of those materials may be 

needed to properly manage the uncertainties.

Recommendation –

Option #3
22

Basis for 20,000 years

• Near-surface disposal is not geologic disposal – the 

stability issues are much more challenging.

• Natural cycling of climate is known/expected.

• A value of 10,000 years is more likely to be in the 

period of climate transition.

• Including climate cycling within the compliance period 

will encourage disposal of long-lived waste at more 

stable sites.
23

Basis for 20,000 years

• While 20,000 years does not capture peak risk for all 

wastes, it captures more than shorter values. Possibly 

within 10x for depleted uranium.

• A value of 20,000 years better captures radionuclide 

transport characteristics (compared to 10,000 years).

• Diminishing returns for longer periods (affected by 

increasing uncertainty).
24

d(Radionuclide Transport)

d(Period of Performance)

Depth 

(Horizontal) Shallow Moderate Deep

Climate 

(Vertical)

Arid Se, Sn, Eu, 

Nb, Mn, Fe

U, Np, C, Sr, I Tc, H, Cl

U, Np, C, Sr, I, 

Semi-arid Pu, Ac, Co, Pa Se, Sn, Eu, 

Nb, Mn, Fe

U, Np, C, Sr, I

Humid Pu, Ac, Co, 

Pa, Zr, Th, Cs

Pu, Ac, Co, Pa Se, Sn, Eu, 

Nb, Mn, Fe

1 Ra, Pb, and Am were not influenced under any of the nine conditions

more

mobile

less

mobile

Sites with slow

water flow

Sites with fast

water flow
25

Basis for No Dose Limit

for Second Tier

• Impacts can be better placed in proper context (NRC 

would complete environmental analysis of impacts for 

disposal licensing actions taking place in non-Agreement 

States).

• Approach better aligned with long-term decision making 

in other programs (e.g. disposal of industrial metals).

• Impacts better aligned with uncertainties.

Basis for No Dose Limit

for Second Tier
26

• Risk-informed, performance-based guidance:

- Would allow flexibility for short-lived waste or low 

concentrations of long-lived waste.

- Would allow to go longer for high-concentrations 

of long-lived waste.

• Expectations for long-term analysis.

Guidance on 

Period of Performance
27

Backup
28

Option #4 – Uncertainty 

Informed Approach (CAP)