'

ACNW MEETING WITH

THE U.S. NUCLEAR

REGULATORRY

COMMISSION

January 11, 2006
OVERVI EW

Michael T. Ryan
Agenda

* Michael Ryan

- Low-level waste white paper

-1 0 CFR Part 63 revisions

- Radiation Protection

-ACNW Action Plan (Tier I and

Tier 11 activities)

3
Agenda

* Ruth Weiner

- Research and Technical

Assistance Activities

* Allen Croff

- Waste Determination

4
Agenda

* James Clarke

- Decommissioning

* William Hinze

- Igneous Activity

5
Low-Level Radioactive

Waste

* White paper summarizes

- History of LLW regulation

- Part 61 regulatory framework

-The LLW classification system

and its uses

- Opportunities for risk-informed

improvements

6
U

Review of ICRP

Documents

* Reviewed the ICRP foundation

documents

* Reaffirms its earlier

recommendation (Nov. 3, 2004)

* No evidence to support a nonhuman biota standard

7
Biological Effects

Report-BEIR VI

Cancer risks have not changed

significantly from previous BEIR

reports

* Linear no threshold model is the

preferred model for radiation

* Newer radiation biology

information is not sufficient at

this time for changes

8
OSHA's Request For

I nformation

e Existing radiation protection

program is effective and robust

* Trends in worker exposures do

not support the need for a new

regulatory initiative

* Comments are focused on

Commission regulated areas or

t

uly

9
ACNW Action Plan (Tier 1)

* Proposed Yucca Mountain

Repository

* Risk-Informing Nuclear Waste

and Materials Regulatory

Activities

* Decommissioning

* Waste Determinations

* Low-Level Radioactive Waste

10
ACNW Action Plan (Tier II)

* Health Physics

* Transportation of Radioactive

Materials,

* Waste Management Research

* Fuel Cycle Facilities

11
Planned Working Groups

* Decommissioning

* West Valley Demonstration

Project

* Modeling and Monitoring

* Cement Materials

* Low-Level Radioactive Waste

* Risk-Significant Yucca Mountain

Issues

12
A N L

ACNVV LETTERS
1 4

UNITED STATES

NUCLEAR REGULATORY COMMISSION

ADVISORY COMMITTEE ON NUCLEAR WASTE

o WASHINGTON. D.C. 20556

June 21, 2005

The-Honorable Nils.J-Diaz _ _.

Chairman

U.S. Nuclear Regulatory Commission

Washington, DC 20555-0001

SUBJECT: PROPOSED RULE ON NATIONAL SOURCE TRACKING OF SEALED

SOURCES

Dear Chairman Diaz:

During Its 159"' meeting on April 18-19, 2005, the Advisory Committee on Nuclear Waste

(ACNW) discussed a proposed rule that would require a national source tracking system for

sealed radioactive sources. The ACNW also discussed sealed source tracking and control

during Its 156wh meeting December 13-14, 2004. The Committee had the benefit of discussions

with the Department of Energy, the Maryland Department of the EnvironmentlRadiological

Health Program, the Conference of Radiation Control Program Directors (CRCPD), and the

NRC staff.

The Committee commends the NRC staff for Its leadership in creating a U.S. sealed source

tracking system. The system will focus on larger sources that pose greater risks. The

Committee believes that the tracking system, as currently envisioned, is appropriate. The

system requires the owners of large sources to register them when manufactured or received,

report changes of ownership when transfer is completed, and annually verify their inventory.

The Committee offers the following recommendations.

The system Is intended to operate online. As a consequence, care must be taken to

ensure the tracking system remains secure from unauthorized entry while still being

accessible to users.

* Information will be entered into the system by the manufacturers or owners of the sealed

sources. The quality of the information entered Into the system must be ensured.

* The Committee continues to see significant progress in the planning for control and

tracking of sealed sources. While the proposed sealed source tracking system is an

appropiate and useful first step, the Committee believes a continuing effort is needed to

make he -tracking-system omprehensive-consistent,-and risk-nformed. Federal-and -

State agencies, the CRCPD, and the Organization of Agreement States should be

encouraged to participate.
a

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We look forward to continuing to work with the staff and the other interested parties as they

develop a national source tracking system.

Sincerely,

Michael T. Ryan

Chairman

Reference:

E-mail to R. Major from M. Hom, dated 313012005, Subject: Proposed Rule-National Source

Tracking of Sealed Sources (RIN 3150-AH48), undated, official use only
4 a

'°p UNITED STATES

NUCLEAR REGULATORY COMMISSION

ADVISORY COMMITTEE ON NUCLEAR WASTE

( WASHINGTON, D.C. 2055-001

June 28, 2005

The Honorable Nils J. Diaz

Chairman

U.S. Nuclear Regulatory Commission

Washington, D.C. 20555-0001

SUBJECT: DEPARTMENT OF ENERGY PLANS FOR TRANSPORTING SPENT NUCLEAR

FUEL AND HIGH-LEVEL RADIOACTIVE WASTE

Dear Chairman Diaz:

At its 159' meeting on April 18-19, 2005, the Advisory Committee on Nuclear Waste (ACNW)

heard a presentation by Gary Lanthrum, Director of the Office of National Transportation (ONT)

of the Department of Energy (DOE).

Summary of the ONT Presentation

ONT will build and operate a system for transporting spent nuclear fuel (SNF) and high-level

radioactive waste (HLW) to a repository at Yucca Mountain, Nevada. ONT has been organized

around four project areas:

* Institutional

* Operational Infrastructure

* Fleet Acquisition

* Rail Through Nevada

The Institutional Project will collaborate with stakeholders to refine the transportation system as

it Is developed. A key effort will be to develop policy and procedures for awarding grants under

Section 180(c) of the Nuclear Waste Policy Act to assist State, Tribal, and local emergency

response personnel in preparing for repository shipments and to develop Information for the

public and interested stakeholders.

The Operational Infrastructure Project will define, develop, implement, and demonstrate the

operational infrastructure needed to support waste transportation from the utility and DOE

locations where the SNF and HLW are currently stored to the proposed Yucca Mountain

repository. The transportation infrastructure is intended to ensure optimal transportation from

the origin sites to Yucca Mountain, but optimization depends on other factors: maximal

utilization of existing casks and other facilities, as few shipments as possible, acceptable and

safe routes, and rapid transportation from each origin site. Optimization is complicated by the

uncertainty about when fuel of various types will be shipped.

The Fleet Acquisition Project will define the approach to purchasing transportation casks and

rolling stock to support transportation to the repository. The ONT's goal Is to procure the

minimum suite of casks and undertake as few certifications as possible. Existing casks will be

used as much as possible, but DOE has found that the existing casks will fill only about 30% of

the need.
a

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A rail line will be built in Nevada to connect the repository to an existing main rail line. ONT is

preparing a rail alignment environmental Impact statement (EIS) in accordance with the

National Environmental Policy Act. DOE is evaluating the environmental inputs of a 31 8-to-344-

mile-long corridor beginning in Caliente, Nevada. As a result of the scoping hearings on this

EIS and the ensuing approximately 4000 comments to DOE, several additional routes are being

considered for the proposed rail line.

DOE is also asking to be allowed to take credit for fuel bumup; i.e., to recognize that relatively

high-bumup fuel has significantly less fissile content, and significantly more radionuclides that

can poison the fission reaction than fresh fuel or low-bumup fuel. ONT said that there is little

data on this topic In the U. S. The French have developed a considerable database and are

working with the DOE. The chance of a criticality Is significantly lowered in high-burnup fuel,

and If this credit is allowed, the amount of SNF In a shipment can be increased. Without

bumup credit, the space in some transportation casks could not be utilized fully. As-the amount

of SNF per shipment Increases, the number of shipments needed decreases.

ACNW Observations

* The entire SNF transport system should be optimized from storage at the site of origin

through transport, receipt, repackaging and emplacement in the drift. The transportation plan should be integrated with the strategy and plan for emplacing the waste in

the repository.

* The DOE plan to try to obtain bumup credit - credit for reducing the risk of criticality in

high burnup fuel - appears to be a wise move toward more realism in analysis of

transportation of SNF and toward increased transportation efficiency.

ACNW Recommendation

NRC staff should consider allowing realistic bumup credit for cask certification.

Sincerely,

Michael T. Ryan

Chairman
a*

UNITED STATES

NUCLEAR REGULATORY COMMISSION

ADVISORY COMMITTEE ON NUCLEAR WASTE

WASHINGTON. D.C. 20555

June 28, 2005

The Honorable Nils J. Diaz

Chairman

U.S. Nuclear Regulatory Commission

Washington, D.C. 20555-0D01

SUBJECT: DEFINITION OF A TIMESPAN OF REGULATORY COMPLIANCE FOR A

GEOLOGICAL REPOSITORY AT YUCCA MOUNTAIN

Dear Chairman Diaz:

In a decision dated July 9, 2004, the U.S. Court of Appeals for the District of Columbia Circuit

ruled that the 1 0,000-year compliance period (hereafter the time period of compliance or TOC)

specified by the U.S. Environmental Protection Agency (EPA) for Its Yucca Mountain sitespecific radiation standards at 40 CFR Part 197 violated Section 801 of the Energy Policy Act of

1992 (EnPA). It is unclear what changes will be made to Part 197 to address this ruling, but

such changes will require the Commission to modify the regulations in 10 CFR Part 63. The

Committee believes it may be useful for the Commission to consider previous ACNW advice on

TOC, as well as other views on TOC.

BACKGROUND

Before 1992 the generic radiation standards and implementing regulations for evaluating

geologic repository sites and licensing repository designs were given at 40 CFR Part 191 and

10 CFR Part 60. In 1992 Congress directed EPA and NRC to develop new radiation standards

and NRC to develop implementing regulations for licensing of the Yucca Mountain site. In

developing radiation standards, Congress directed EPA to contract with the National Academy

of Sciences (NAS) to advise EPA on the appropriate technical basis for public health and safety

standards for any Yucca Mountain repository.

On August 1, 1995, the NAS issued its report, "Technical Bases for Yucca Mountain Standards"

(the TYMS report). The NAS concluded there was "no scientific basis for limiting the time

period of the individual risk standard to 10,000 years or any other value." According to the

Academy, "compliance assessment is feasible for most physical and geologic aspects of

repository performance on the time scale of the long-term stability of the fundamental geologic

regime - a time scale that is on the order of one million years at Yucca Mountain." The

Academy also concluded that humans may not face peak radiation risks until tens to hundreds

of thousands of years after the disposal of wastes, "or even farther into the future." The

Academy thus recommended 'that compliance assessment be conducted for the time when the

greatest risk occurs, within the limits imposed by the long-term stability of the geologic

environment."
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After the Academy Issued its findings and recommendations, EPA promulgated its draft Part

197 standards In which It proposed a 10,000-year TOC. In so doing, EPA requested comments

on the reasonableness of adopting the NAS-recommended TOC or 'some other approach In

lieu of the 10,000-year compliance period,' that EPA favored. During the public comment

period, DOE and NRC went on record supporting the 10,000-year TOC while the State of

Nevada proposed adopting a TOC extending to the time of projected peak dose, as NAS

recommended. After reviewing the public comments, EPA promulgated its final rule adopting

the 10,000-year TOC and In doing so expressed the view that NAS' TOC recommendation was

'not practical for regulatory decision-making.'

PAST ACNW ADVICE

The most recent ACNW views on TOC were given In two 1996 letters. The first letter gave

background on defining a repository TOC, discussed related regulatory principles and selection

criteria, and recommended a two-tiered approach to defining a TOC.W The second letter

provided additional detail on the proposed two-tiered approach to addressing TOC Issues.2

The first tier of the ACNW recommended approach was to define a quantitative dose limit for

the reasonably maximally exposed individual (REMI) at a specific time for times on the order of

several thousand years. The second tier was to qualitatively compare the peak dose and

uncertainties of the dose standard. The Committee's recommendation did not require a

quantitative measure of compliance at the TOC because of the uncertainties In defining future

processes and events.

INTERNATIONAL APPROACHES

There is no International consensus on TOC among standard-setting bodies, regulators, and

developers. This is not surprising considering the differences In national policies and the

variations in design concepts and geologic settings. The attached table shows the variability of

intematronal TOC durations. Generally, a multitier approach to timeframes Is used with a

quantitative evaluation based on an early assessment of 1000 to 10,000 years and a longer,

qualitative evaluation of a million years or longer, but there are many exceptions. Some

countries, such as Germany, have not specified a TOC, but are considering the use of safety

indicators with a qualitative assessment to a million years or more but no less than 10,000

years. Canada has specified a 10,000-year TOC and requires evaluation to an unspecified

period beyond 10,000 years to show that there are no dramatic increases in dose in the postTOC years.

Member countries of the International Atomic Energy Agency and the Nuclear Energy Agency

(NEA) are participating in continuing activities to develop a consensus on using the results of

performance assessments over long periods of time. Both organizations have recommended a

tiered approach for evaluating repository performance. Deliberations on this issue continue. In

the Fall of 2005, we expect to review a draft report on NEA's most recent workshop.

ACNW letter report dated June 7, 1996, 'ime Span for Compliance of Proposed Yucca Mountain HLW

Repository.'

2 ACNW letter report dated November 14, 1996, Road Map to ACNW's Recommendation for TOC "
a

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PATH FORWARD

Upon the release of EPA's draft rulemaking for public comment, the Committee plans to review

the draft regulation, meet with the NRC staff and stakeholders, and report Its observations and

recommendations to the Commission. The Committee also anticipates being briefed on the

results of a 2005 NEA workshop. The briefing will be useful in the NRC's effort to help develop

an international consensus on the use of long-timeframe performance assessment results.

In addition, the ACNW plans to hold a working group meeting in the Fall of 2005 on technical

issues associated with long-timeframe performance assessments at Yucca Mountain. The

Committee will report to the Commission on the results of this working group meeting.

Sincerely,

Michael T. Ryan

Chainnan

Attachment:

As stated
ATTACHMENT

INTERNATIONAL APPROACHES TO DEFINING

A REGULATORY TIME OF COMPLIANCE (TOC)

More than 30 countries have research and development programs for managing long-lived

radioactive wastes in geologic repositories (Witherspoon and Bodvarsson, 2001'). Currently,

there is no International consensus among standard-setting bodies, regulators, or developers

in these countries on the time scale for evaluating the safety of geologic repositories. An effort

is underway in the Nuclear Energy Agency to address this Issue (by NEA's Integration Group

for the Safety Case or IGSC). This Timescales Project has produced two reports so far. " A

third 'state-of-the-art report" is In preparation and will likely be published in 2006.4

The table below lists TOCs for 10 countries, including the United States, that have standards

or guidance in place for evaluating the safety of long-lived radioactive waste repositories. A

review of the literature indicates that several of these countries have TOCs that range from

1000 to 1,000,000 years. In some cases, there Is no regulatory TOC cutoff and the

calculations can be carried out to as long as 100 million years after facility closure. The

technical bases for the specification of a particular TOC vary among developers and

regulators. Cutoff times (i.e., the duration of the TOC) have been justified on the basis that

(a) the relative hazard (toxicity) of spent nuclear fuel vs. a naturally occurring uranium ore

body; (b) the potential for multiple peak doses to future receptors; and/or (c) Intergenerational

equity concems. For the purposes of comparison, the table includes the three time frames

selected by the Intemational Atomic Energy Agency (IAEA) for an analysis of the use of

repository safety Indicators.

PA Witherspoon and G.S. Bodvarsson (eds.), 'Geological Challenges In Radioactive Waste Disposal - Third Worldwide Review,' Berkeley, Ernest Orlando Lawrence Berkeley National Laboratory, LBNL-49767, December 2001.

2 Nuclear Energy Agency, 'The Handling of Timescales In Assessing Post-Closure Safety of Deep Geological Repositories, Proceedings of April 16-18, 2002, Workshop, Paris, France, Paris, Nuclear Energy Agency/Organization for Economic Cooperation and Development, 2002. Also see Nuclear Energy Agency, mIntegration Group for the Safety Case (IGSC) Workshop oh Handling of Time Scales Assessing Post-Closure Safety - Compilation of Abstracts,- Paris, Nuclear Energy Agency/Organization for Economic Cooperation and

Development, NEAIRWMIIGSC(2002)6, June 2002.

3 Nuclear Energy Agency, eThe Handling of Timescales in Assessing Post-Closure Safety - Lessons

Learnt from the April 2002 Workshop in Paris France,' Paris, Nuclear Energy Agency/Organization for Economic

Cooperation and Development, NEA No. 4435,2004.

4 Belgium proposed the Timescales Project to NEA's IGSC. The purpose of the project is to produce a

'state-of-the-art report to document a consensus for cutting off performance assessment calculations at a specific

time, If possible. Belgian officials believe that It would be helpful tof be able to cite an international report with a

recommendation and a technical basis for the recommendation. Although the NEA document has not been drafted,

a 1 million-year cutoff is beginning to emerge as an informal consensus TOC based on discussions among the

participants.

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A related concern is to use performance assessment results in accounting for the uncertainties

of analyses. Performance assessments In timespans of less than 100,000 years are generally

considered more reliable. Longer term assessments (TOCs greater than 100,000 years) are

generally considered less reliable because the uncertainties increase with time.

Regardless of the length of the specified TOC, there is a consensus among practitioners that a

mutitier approach should be used to judge repository performance, as noted in the table

below. Performance assessments of TOCs of less than 100,000 years are generally more

quantitative and TOCs of more than 100,000 years are generally more qualitative.

Country TOC Comments

BELGIUM Not established yet Safety demonstration analyses for at least

100,000,000 years. I

CANADA b 10,000 years Demonstrate repository safety quantitatively with

detailed calculations.

< 100,000 years Qualitative demonstration, using ureasoned

arguments,' that there Is no dramatic Increase in

releases from repository after the first 10,000 years.

c 1,000,000 years An example for the purposes of the environmental

impact statement to demonstrate that the radiological

toxicity of spent fuel Is equivalent to a natural uranium

ore body.

FINLAND d e 10,000 years Evaluate repository performance over an

environmentally predictable period.

• 10,000 years Do a stylized, quantitative calculation using a broad

range of safety indicators.

• 1,000,000 years Do a qualitative calculation.

FRANCE 0-500W years f Do analysis for assumed period of passive institutional controls.

c 50,00D years Minimum period of environmental predictability.

Analysis not Intended to reflect future climate change

and the onset of glaciation.

* 50,000 years Do a qualitative analysis as a reference, taking into

account the expected evolution of repository system.

GERMANY No specified time Evaluate repository performance up to about 10,000

years, taking Into account period during which

repository barriers would be subject to minor

changes.b

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Country TOC Comments

Do an analysis on the order of 1,000,000 years to

Identify repository sites with overall favorable geologic

characteristics. ' Do other demonstration analyses for

beyond 1,000,0D0 years. '

JAPAN b Not established yet Evaluate repository performance taking Into account

period of peak dose up to about 100,000,000 years."

SPAIN' Not established yet Demonstration analysis to stop at 1,000,000 years.

(To be defined by

2010.)

SWEDEN J c 1000 years Do a quantitative calculation.

c 100,000 yearsk Do a quantitative analysis, taking into account the

next major glacial period. The analysis period must

be greater than 10,000 years.

> 100,000 years Do a stylized, qualitative calculation. The analysis is

to stop at 1,000,000 years.

SWITZERLAND b No specified time Duration for demonstration analysis terminated at

10,000,000 years.'

UNITED Not established yet Tirneframe for analysis Implied to be less than

KINGDOM b 1,000,000 years.

UNITED STATES 10,000 years m Timeframe for analysis for evaluation of transuranic

(TRU) radioactive wastes.

1,0O0,000 yearsn° Evaluate Yucca Mountain repository performance,

taking into account periods of peak dose up to about

1,000,000 years.

MAEAP C 10,000 years Quantitative analysis assuming the current biosphere

and Institonal controls.

c 1,000,000 years Mix of qualitative and quantitative illustrative

calculations Intended to reflect future climate change

and the present-day reference biosphere

> ,000,ODO years Qualitative analysis during the period over which

radiological toxicity of repository is equivalent to a

natural uranium ore body.

REFERENCES:

a Studiecentrum voor Kemenergie - Centre d'rtude de rEnergie Nucleaire (SCK'CEN -

Belgian Nuclear Research Centre), identiying and Testing Indicators for Assessing the

Long Term Perfornmance of Geological Disposal Systems: The [European] SPIN Project,

SCKCEN Scientific Report 2002, Mol, Belgium, [2002].

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A

b U.S. General Accounting Office, "Nuclear Waste - Foreign Countries' Approaches to

High-Level Waste Storage and Disposal," Washington, DC, Resources, Community and

Economic Development Division, GAO/RCED-94-172, August 1994.

C Atomic Energy of Canada Limited, "Environmental Impact Statement on the Concept for

Disposal of Canada's Nuclear Fuel Waste," Mississauga, Ontario, AECL-10711, COG93-1, September 1994.

d The Radiation Protection and Nuclear Safety Authorities in Denmark, Finland, Iceland,

Norway, and Sweden, "Disposal of High Level Radioactive Waste - Consideration of

Some Basic Criteria," Stockholm, Sweden, Swedish Radiation Protection Institute

(Statens Stralskyddsinstitut - SSI), 1993.

Committee on a Site Selection Procedure for Repository Sites (Arbeitskreis

Auswahlverfahren Englagerstandorte - AkEnd), "Site Selection Procedure for

Repository Sites: Recommendations of the AkEnd," Berlin, German Federal Ministry for

the Environment, Nature Conservation, and Nuclear Safety, December 2002.

U.S. Environmental Protection Agency, "Spent Nuclear Fuel and High-Level Waste

Programs Disposal Programs in Other Countries (Chapter 3) in Environmental Radiation

Protection Standards for Yucca Mountain, Nevada - Draft Background Information

Document for Proposed 40 CFR 197, "Office of Radiation and Indoor Air, EPA 402-R99-008, August 1999.

° Bundesanstalt fOr Feowissenschaften und Rohstoffe, "Grundsatze der Endlagerung

radioaktiver Abf~lle - Die Sicherheitsphilosophie des Bundesamtes fOr Strahlenschutz

(Standards for the Permanant Disposal Site for Radioactive Waste - Safety Philosophy

of the Federal Office of Radiation Protection), Salzgitter, German Federal Republic,

2004.

h Japan Nuclear Cycle Development Institute [JNC], OH12: Project to Establish the

Scientific and Technical Basis for HLW Disposal in Japan - Supporting Report 3: Safety

Assessment of the Geological Disposal System," Ibaraki, Japan, Report TN1410 2000-

004, 2000. [NOTE: Because of the current regulatory mandate to address International

practices and standards, the Japanese are actively participating in the NEA Timescales

Project]

A. Astudillo, "Geological Disposal of High-Level Radioactive Wastes In Spain," in P.A.

Witherspoon and G.S. Bodvarsson (eds.) Geological Challenges in Radioactive Waste

Disposal - Third Worldwide Review, Ernest Orlando Lawrence Berkeley National

Laboratory, LBNL-49767, December 2001.

Swedish Radiation Protection Institute, "Health, Environment and Nuclear Waste, SSI's

Regulations and Comments," Stockholm, Sweden, SSI Report 99:22, 1999.

k Swedish Nuclear Power Inspectorate (Statens Knmkraffinspektion), the repository

developer whose implementing recommendations, including a time scale for the

analysis, will be defended at the time of licensing.

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National Cooperative for Radioactive Waste (National Genossenschaft for die Lagerung

radioaktiver AbfIlle - Nagra), "Project Opalinus Clay. Safety Report - Demonstration of

Disposal Feasibility for Spent Fuel, Vitrified High-Level Waste and Long-Lived

Intermediate-Level Waste (Entsorgungsnachwels)," Wettingen, Switzerland, Nagra

Technical Report NTB 02-05, 2002. (Although the demonstration calculations were

carried out to 10 million years, the Nagra report notes that there is little confidence In the

calculations beyond 1 million years.)

m U.S. Environmental Protection Agency, "40 CFR Part 191: Environmental Standards for

the Management of Spent Nuclear Fuel, High-Level and Transuranic Radioactive

Wastes; Final Rule," Federal Register, Vol. 50, No. 182, pp. 38066-38089, September

19,1985.

National Research Council, 'Technical Bases for Yucca Mountain Standards,"

Washington, DC, Commission on Geosciences, Environment, and Resources, National

Academy Press, July 1995.

U.S. Department of Energy, 'Final Environmental Impact Statement for a Geologic

Repository for the Disposal of Spent Nuclear Fuel and High-Level Radioactive Waste at

Yucca Mountain, Nye County, Nevada, Vol. 1, Impact Analyses, Chapters 1 through 15,

"Office of Civilian Radioactive Waste Management, DOE/EIS-0250, February 2002.

International Atomic Energy Agency, "Safety Indicators In Different Time Frames for the

Safety Assessment of Underground Radioactive Waste Repositories. First Report of

the INWAC Subgroup on Principles and Criteria for Radioactive Waste Disposal,"

Vienna, Austria, IAEA-TECDOC-767, October 1994. (The NEA suggestion to evaluate

until the dose from the spent fuel is equivalent to a uranium ore body would not likely

require calculation beyond a million years.)

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.1 a

UNITED STATES

NUCLEAR REGULATORY COMMISSION

ADVISORY COMMITTEE ON NUCLEAR WASTE

WASHINGTON, D.C. 20555-0001

July 1, 2005

The Honorable Nils J. Diaz

Chairman

U.S. Nuclear Regulatory Commission

Washington, DC 20555-001

SUBJECT: COMMENTS ON ICRP FOUNDATION DOCUMENTS - A FOLLOWUP TO THE

ACNW'S NOVEMBER 3,2004 COMMENTS

Dear Chairman Diaz:

The ACNW has reviewed the five 'Foundation Documents' offered by the International

Commission on Radiological Protection (ICRP) In support of its 2005 Draft Recommendations.

By this letter the ACNW reaffirms the recommendations in our November 3, 2004 letter and In

the March 16, 2005 briefing to the Commission. Nothing in the Foundation Documents

changes our earlier observations and recommendations.

As the ACNW stated, the Commission should consider deferring action on any of the Draft

ICRP Recommendations until BEIR VII is published and available for review, and consider

implementing changes In tissue weighting factors, radiation weighting factors, and more recent

methods and models for assessment of internal dose. There is no urgent need to make these

changes; they can be made when regulations are revised for other reasons.

The ACNW has several observations on the Foundation Documents:

1. As written the Foundation Document on the 'Representative Individual" lacks clarity.

Even though it usefully clarifies compliance with dose limits (constraints); the term

'representative Individual" is used In different senses in the document. The definitions

and their applications need to be clarified. Examples could be used to convey the intent

and use of the various dose assessment protocols and strategies discussed in the

document.

2. Unless substantial clarifications are made to the definition and use of the 'representative

individual" concept, it offers little use when compared to the concepts of the 'Average

Member of a Critical Group' or the "Reasonable Maximally Exposed Individual' (RMEI).

3. Consistent with its November 3, 2004 letter, the ACNW recommends that the

Commission defer consideration of the Foundation Documents regarding the 'Biology'

and 'Dosimetry" until the BEIR VII Committee report is issued and available for review

and comparison.
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4. The ACNW believes that the additional guidance provided in the Foundation Document

on "Optimization" would not substantially improve current ALARA programs, or

protection of workers, the public, or the environment. The principle of stakeholder

involvement discussed in the Optimization document is consistent with the

Commission's current programs and activities as discussed in the agency's Strategic

Plan and implementing documents.

5. Regarding the draft Foundation Document on "The Concept and Use of Reference

Animals and Plants for the Purposes of Environmental Protection," the ACNW continues

to hold the view expressed during our March 16, 2005 briefing to the Commission: that

there has been no evidence to contradict the philosophy that by protecting humans the

environment is protected. This Foundation Document tries to make the case that

separate recommendations are needed or justified.

More detailed comments are given on the foundation documents in the Attachment.

Sincerely,

Michael T. Ryan

Chairman

Attachment: Detailed comments on the

ICRP Foundation Documents
i

ATTACHMENT: DETAILED COMMENTS ON THE ICRP FOUNDATION DOCUMENTS

Foundation Document "Assessing Dose of the Representative Individual for the Purpose

of Radiation Protection of the Public"

The document Is very repetitive. Basic concepts, ideas, and approaches are repeated many

times. Unfortunately, terms like "representative Individual" are slightly different in each instance.

The Abstract, Executive Summary, and Introduction all cover the same ground with different

terminology.

The value of the document is derived from its focus on several principles:

1. Both nonstochastic (deterministic) and stochastic assessments have a place. The

document offers comments on where each Is best employed. The document should be

more focused on this point. Clear examples should be given for each case and the

limitations should be spelled out. A common criticism of nonstochastic analysis Is that

true risk can be missed. ICRP should offer a case to counter this assertion. -

2. For nonstochastic assessments, doses below a limit (constraint" in ICRP terminology)

demonstrate compliance. This Is a helpful statement

3. For probabilistic risk assessment, the document suggests compliance with a dose limit

If the 95th percentile of the dose distribution Is within a factor of 3, compliance Is

demonstrated. This needs clarification. Additionally, the ICRP should advise regulators

on how to make the compliance algorithm clear. Examples would help to demonstrate

these concepts.

Major drawbacks to the document are:

The representative Individual," as presented in the document, is discussed in contradictory

ways. Paragraph 23 states:

Therefore, for the purpose of protection of the public, it is necessary to

characterize an Individual, either hypothetical or specific, who receives

the highest dose which can be used for determining compliance with the

dose constraint. This individual is defined as the representative individual.

How can a representative Individual get the ohighest dose?"

Paragr aph (S9) uses a slightly different definition:

The representative individual is the hypothetical Individual receding a

dose that is representative of the most highly exposed individuals in the

i population.

This definition implies that the representative individual is a member (perhaps the average,

median, or mode) of the most highly exposed group. This qualitative definition is subject to

Interpretation and is not consistent with paragraph 23.

41-
Paragraphs 67 and 68 imply that the representative individual possessed 'mean' characteristics

regarding habits that are not 'outside the range of day-to-day life.' This Is not easily reconciled

with the Individual who receives 'the highest dose.' ICRP needs to clarify the definition and

guidance.

Temporal uncertainty and variability seem not to have been considered. It appears that the

approaches to dose calculations address only uncertainty and variability In spatial data. This

report seems to indicate that once determined (for a specific point in time), the parameters used

to model pathways of exposure and calculated dose are fixed throughout the entire life span of

the exposed Individual. The dose calculations need to consider temporal uncertainty and

variability over time. Both are known to be Important.

Foundation Document "Biological and Epidemlological Information on Health Risks

Attributable to lonising Radiation: A Summary of Judgements for the Purposes of

Radiological Protection of Humans"

1. This Foundation Document suggests small adjustments to 'detriment adjusted nominal

probability coefficients for cancer.' These small adjustments do not substantially

change previous cancer risk values. In addition, additional analyses are expected In the

Biological Effects of Ionizing Radiation Committee of the National Academy of Science

Report (BEIR VII), expected later this year. The ACNW continues to believe that the

Commission should consider deferring action on any of the draft ICRP

recommendations until the BEIR VII Report Is published and available for review.

2. A related finding is reported: 'For cancer and hereditary disease at low doses/dose

rates the use of a simple proportionate relationship between Increments of dose and

increased risk is a scientifically plausible assumption." This conclusion further supports

taking no action until the BEIR VII report is published. ICRP recommends no large

changes in risk factors.

3. The Foundation Document states: wKnowledge of the roles of Induced genomic

instability, bystander cell signaling and adaptive response in the genesis of

radiation-induced health effects is Insufficiently well developed for radiological

protection purposes: In many circumstances these cellular processes will be

incorporated in epidemiological measures of risk.' The ACNW believes that this

statement Is a fair assessment of the state of knowledge of these issues at this time

though new information is reported regularly. The ACNW will keep informed of newer

studies and report to the Commission as appropriate.

4. The document states: 'Proposed changes in radiation weighting factors for protons and

neutrons are noted; these judgements are fully developed in the ICRP Committee 2

Foundation Document, Basis for dosimetric quantities used in radiological protection

(FD-C-2)". This additional report provides substantive detail. The Foundation Document

on 'Biological and Epidemiological Information..." states that: 'New radiation detriment

values and tissue weighting factors have been proposed; the most significant changes

from ICRP 60 relate to breast, gonads and treatment of remainder tissues.' ACNW's

comments on FD-C-2 are provided separately below.

-2-
a 5

Foundation Document "Draft for Discussion International Commission on Radiological

Protection Committee 2 Basis for Dosimetric Quantities Used In Radiological Protection"

The two principal recommendations In this report are to change the radiation weighting factors

for protons and neutrons and change the fissue weighting factors used to calculate the effective

dose (formerly referred to as dose equivalent).

For protons, the ICRP recommends that the weighting factor be lowered from 5 (the value

recommended In ICRP Publication 60') to 2. Currently, in 10 CFR 20.1004, Table 1004(B).1,

Quality Factors and Absorbed Dose Equivalencies, a quality factor of 10 is given for high

energy protons. Consistent with our letter of November 3, 2004, the ACNW believes that the

Commission should consider updating this quality factor, but that the update can be done by

issuing regulatory guidance or at a time when the regulations are revised for other reasons.

The ICRP has developed a method to calculate the quality factor for neutrons as a function of

neutron energies. Three equations for three different energy ranges are recommended in

Equation 4.7:

I2.5 +

W =I 5.0+17.Oe *(2E3f

2.5 + 3.25e{wL,)r

I E c<1 IWV

9 1 MetVEs S5 O1feV

, E, < 50 MeV

(4.7)

Neutron energy Quality factor (Q) 10 Values Calculated Ratio of ICRP

(MeV) (thermal) ..... CFR 20.1004 (B) 2 from New ICRP Recommended

Methods Value to Current 10

CFR 20.1104

2.50E-08 2 2.5 1.25

1.00E-07 2 2.5 1.25

I.OOE-06 2 2.5 1.25

I.OOE-05 2 2.5 1.25

1.OOE-04 2 2.5 1.25

1.OOE-03 2 2.5 1.25

1.OOE-02 2.5 3.0 1.21

1.OOE-01 7.5 10.0 1.34

5.ODE-01 11 19.3 1.75

1 11 22.0 2.00

2.5 9 19.8 2.20

The table above shows that the current quality factors for neutrons differ from those using the

ICRP's recommended formulas by factors ranging from 1.21 to 2.20. These factors are not

substantially different and given the uncertainties in determining neutron spectra in practical

I ICRP. 1990 Recommendations of the ICRP. ICRP Publication 60. Ann of Mhe ICRP, 21(1-3).

Pergamon Press, Oxford (1991).

-3-
radiation protection situations, these factors may often be comparable to the errors associated

with such measurements. Consistent with Its letter of November 3, 2004, the ACNW believes

that the Commission should consider Incorporating this method of calculating neutron quality

factors, but that the update can be done through regulatory guidance or at a time when the

regulations are revised for other reasons.

This Foundation Document, along with the Foundation Document on Biological and

Epidemiological Information, also suggests changes to tissue weighting factors:

in the proposals for the new Recommendations the WT for remainder

(0.12) is divided equally between the 15 specified tissues given In Table

2, i.e. approximately 0.008 each. This value Is smaller than the least

value assigned to any of the named tissues (0.01). In practice this gives

the arithmetic average of the doses to these 15 tissues. Since the

formulation of remainder Is the same In every case the system preserves

additivity in effective doses which is a considerable advantage in practical

radiation protection.

This change clarifies how to calculate dose to other organs not specifically assigned weighting

factors.

In changing these weighting factors, to be consistent It would be necessary to recalculate the

existing Annual Limits on Intake and Derived Air Concentrations used in current regulations.

"The Optimisation of Radiological Protection -Broadening the Process," Report by the

ICRP Committee 4 Task Group on Optimlsation of Protection

The ACNW observed in Its letter of November 3, 2004, that

current ICRP recommendations ....[are] sufficient regarding

noptimization." The Committee questions whether the draft ICRP

recommendations are really Improvements. ALARA as practiced in the

U.S. provides a framework for accomplishing much of what the ICRP

says about Ooptimization." ALARA is well understood and ALARA

programs identify both dose reduction opportunities and other safety

Issues. The draft ICRP recommendations would unnecessarily complicate

existing ALARA principles and applications with new terminology or

dimensions."

The ACNW believes the additional guidance provided in this Foundation Document would not

substantially improve current ALARA programs or protection of workers, the public, and the

environment.

Additionally, this Foundation Document provides ICRP's views on the "role of the

stakeholder." The ACNW believes that the Commission has developed significant

initiatives to involve stakeholders in the regulatory process as described in the Strategic

-4-
Plan and implementing documents and programs, particularly with regard to 'openness"

[reference: NRC's Strategic Plan: FY 2000 - FY 2005, NUREG-1614, Vol. 2, part 1].

Foundation Document: "The Concept and Use of Reference Animals and Plants for the

Purposes of Environmental Protection"

The ACNW believes that the ICRP has failed to make a case for overturning the principle that

has guided radiation protection practice for more than 50 years. This principle states that

protecting humans also protects the environment. The ICRP says in paragraph (6):

The Commission [ICRP] still believes that this judgement is likely to be

correct in general terms, because the steps taken to protect the public, by

reference to dose limits for them, have resulted in strict controls and

limitations on the quantities of radionuclides deliberately introduced into

the environment.

The ACNW believes that the ICRP has not provided any evidence to contradict this longstanding principle.

Further, it seems clear that the ICRP's guidance is driven by other concerns. As the ICRP

states:

However, there are now other demands upon regulators, in particular the

need to comply with the requirements of legislation directly aimed at the

protection of wildlife and natural habitats; the need to make

environmental impact assessments with respect to the environment

generally; and the need to harmonise approaches to industrial regulation,

bearing in mind that releases of chemicals from other industries are often

based upon their potential impact upon both humans and wildlife.

The ACNW believes that this ICRP recommendation goes far beyond radiation protection

issues and is more relevant to strategies for national policy on radiation protection. It is telling that in the last quote the ICRP cites 'chemicals from other industries as an example but does

not explain why radioactive materials should be included with chemicals. The justification for

this linkage is not clear and in any case is not developed or substantiated in the text

-5-
X I

UNITED STATES

NUCLEAR REGULATORY COMMISSION

ADVISORY COMMITTEE ON NUCLEAR WASTE ACNW R-0224

WASHINGTON, DC 20555 - 0001

July 27, 2005

The Honorable Nils J. Diaz

Chairman

U.S. Nuclear Regulatory Commission

Washington, D.C. 20555-0001

SUBJECT: RESPONSE TO THE OCCUPATIONAL SAFETY AND HEALTH AGENCY

REQUEST FOR INFORMATION ON IONIZING RADIATION

Dear Chairman Diaz:

On May 3, 2005, the Occupational Safety and Health Agency (OSHA) submitted the following

request for information In the Federal Register:

OSHA requests data, Information and comment on Issues related to the

increasing use of ionizing radiation in the workplace and potential worker

exposure to it. Specifically, OSHA requests data and information about the

sources and uses of ionizing radiation in workplaces today, current employee

exposure levels, and adverse health effects associated with Ionizing radiation

exposure. OSHA also requests data and Information about practices and

programs employers are using to control employee exposure, such as exposure

assessment and monitoring methods, control methods, employee training, and

medical surveillance. The Agency will use the data and information it receives to

determine what action, if any, is necessary to address worker exposure to

occupational ionizing radiation.

The Advisory Committee on Nuclear Waste (ACNW or Committee) considered OSHA's request

for information (RFI) as published In the Federal Register and Is providing its independent views

on OSHA's RFI.

The Committee notes that many components of a robust system of radiation protection,

including radiation protection programs, regulations and regulatory agreements, and other

sources of information, already exist:

1. NRC and Agreement States regulations promulgated for activities regulated by the

Atomic Energy Act (AEA);

2. State radiation protection programs for non-AEA radioactive materials;

3. Federal guidance on sources of electronic product radiation from the Center for Devices

and Radiological Health of the Food and Drug Administration;

4. State programs for electronic product radiation control;

5. U.S. Environmental Protection Agency general applicable radiation protection statutes

and related guidance;
I

-2-

6. U.S. Department of Energy radiation protection statutes (10 CFR Part 835,

0Occupational Radiation Protection"), regulations, orders, and guidance;

7. Reports of the National Academy of Sciences, Including the recent report "Health Risks

from Exposure to Low Levels of Ionizing Radiation" Biological Effects of Ionizing

Radiation (BEIR) VII - Phase 2, 2005;

8. The Conference of Radiation Control Program Directors (CRCPD) and the Organization

of Agreement States (OAS) programs that support Agreement State and non-Agreement

State radiation protection programs;

9. The CRCP D and OAS joint letter to OSHA regarding its RFI;

10. NRC data on occupational radiation exposure (NUREG-0713, Volume 25, 'Occupational

Radiation Exposure at Commercial Nuclear Power Reactors and Other Facilities," 2003);

11. Nuclear Energy Institute (NEI) data on occupational radiation exposure;

12. Guidance offered by the National Council on Radiation Protection and Measurements

(NCRP); and

13. OSHA-NRC Memoranda of Understanding.

This information demonstrates that existing programs provide adequate radiation protection to

workers. We have summarized some of the information in the appendix to this letter.

The Committee also believes that the premise of OSHA's request for information that worker

exposure might be increasing is not substantiated. For example, the ACNW notes that in Table

3.1 of NUREG-0713 (see the appendix to this letter), the trend in average measurable Total

Effective Dose Equivalent (TEDE) per worker has decreased In every one of the six categories

of NRC licensees (from 1994 to 2003).

The Committee did not have access to any comprehensive database for radiation dose

information for radiation workers in medical areas that use non-AEA radioactive materials or

electronic product radiation devices and cannot comment on trends for these workers. The

ACNW notes that these workers' groups are monitored under State authority. The 33

Agreement States typically integrate these non-AEA radiation worker monitoring and protection

programs into NRC-approved programs. Nonetheless, the ACNW cannot include this radiation

worker group in the remaining comments in this letter.

The NEI provided additional analysis to the Committee indicating a clear trend in worker dose

reduction In the nuclear power industry for collective dose per reactor and collective dose per

megawatt year of operation. The NEI data on average annual number of workers with

measurable dose for the period of 1973 - 2003 show a decreasing trend since 1984. The NEI

reported that these trends are a result of robust As Low As Reasonably Achievable (ALARA)

programs rather than a focus only on strict numerical standards. The ACNW interprets the data

to indicate that the current limits, along with the implementation of the ALARA principle, have

been effective in providing radiation protection for workers.
-3-

While collective dose for Department of Energy (DOE) workers has increased from 2002 - 2003,

this increase reflects more work activities rather than an Increase for Individual workers

(DOEIEH-0688, -DOE Occupational Radiation Exposure 2003 Report).

Moreover, the recently released BEIR VIl report affirms that cancer risk estimates for exposure

to Ionizing radiation have not changed significantly from those reported in previous BEIR

reports.

In summary, the ACNW believes that existing radiation safety programs and the current

regulatory infrastructure promote effective and timely oversight of occupational radiation

protection programs required under Federal and State authorities. Furthermore, documented

trends in worker exposures do not support the need for a new regulatory Initiative. The ACNW

recommends that the Commission provide a response to OSHA consistent with this view.

Sincerely,

/RAN

Michael T. Ryan

Chairman
-3-

While collective dose for Department of Energy (DOE) workers has increased from 2002 - 2003,

this Increase reflects more work activities rather than an increase for individual workers

(DOE/EH-0688, -DOE Occupational Radiation Exposure 2003 Reporr).

Moreover, the recently released BEIR Vil report affirms that cancer risk estimates for exposure

to ionizing radiation have not changed significantly from those reported in previous BEIR

reports.

In summary, the ACNW believes that existing radiation safety programs and the current

regulatory infrastructure promote effective and timely oversight of occupational radiation

protection programs required under Federal and State authorities. Furthermore, documented

trends In worker exposures do not support the need for a new regulatory Initiative. The ACNW

recommends that the Commission provide a response to OSHA consistent with this view.

Sincerely,

Michael T. Ryan

Chairman

DOCUMENT NAME: C :WyFiles;Checkout1OSHA Final Letter.wpd

To receive a copy of this docunent, Indicate In the box: C a Copy wlitho

Copy with attachmentlendosure 'N" = No copy Access lOFFICE ACRSIACNW I Y I ACRSIACNW I Y ACRSIACNW

NAME SSteele I MScott JLarklns

DATE 07127105 107127105 07127105

OFFICIAL RECORD COPY

at attachmentlenclosure "E" a

;Ion#: ML052090017

.Y ACRSIACNW I Y ACNW Iy

AThadani MTRyan

07127105 07127105
APPENDIX

INFORMATION EVALUATED BY ACNW REGARDING OSHA'S

REQUEST FOR INFORMATION (RFI)

NRC Data on Occupational Radiation Exposure

NRC summarizes Information regarding worker exposure from its databases for several industry

segments. The latest available summaries are provided in NUREG-0713, Volume 25,

0Occupational Radiation Exposure at Commercial Nuclear Power Reactors and Other Facilities."

Example data from NUREG-0713 (Table 3.1) are provided below. The table shows the average

annual exposure for certain categories of NRC licensees: namely industrial radiography,

manufacturing and distribution, lowlevel waste disposal, Independent spent fuel storage, fuel

cycle licenses, and commercial light water reactors. The table Indicates a downward trend in

the collective dose (person-rem) from 1994 to 2003 across the Industries measured. This

observation further supports ACNW's view that the system of radiation protection is robust and

effective; thus, OSHA need not Intervene to address worker exposure to occupational Ionizing

radiation.

Agreement State Programs

In its recent review of the NRC Agreement States program, the ACNW found the radiation

program to be robust and effective In providing radiation protection programs for workers

regulated under both Atomic Energy Act (AEA) and non-AEA-regulatory authority. ACNW has

reported previously on the Integrated Material Performance Evaluation Program (IMPEP),

created to oversee and review the Agreement States program. IMPEP results are used to

determine the adequacy and compatibifity of individual Agreement State programs. In the

ACNW's 2005 letter to the Commission, 'Status of the Agreement State Program and the

Integrated Materials Performance Evaluation Program (IMPEP),' the Committee stated the

following:

Two key factors make the IMPEP program proactive rather than reactive, and risk

Informed and performance based rather than prescriptive. First, the collaboration of

Independent Agreement State staff members and NRC's regional materials program

staff on review teams provides for consistency among the States and lets them share

their results and experiences. This interaction has led to Improved risk-informed

approaches and procedures. Second, IMPEP ratings and responses use a graded

approach with progressively more significant levels of action.

Future inspection frequency and the depth of interaction with Agreement States Program

staff are determined by review of a program's performance.

This graded approach allows for effective oversight and identification of Agreement

State programs needing attention, so that corrective measures can be implemented

before significant problems arise.
S
4

Environmental Protection Aaencv (EPA) Radiation Protection Pro-rams and Reauirements

The EPA has responsibility for protecting the public with considerable authority for developing

radiation protection program guidance and setting environmental standards. The EPA has

wide-ranging authority to promote, conduct, or contract research for radiation protection

information; to promulgate generally applicable environment standards which limit man-made

radioactive materials; to provide technical assistance to the States and other Federal agencies

with radiation protection programs; to advise them in the execution of such programs; and to

provide emergency assistance in responding to radiological emergencies. While EPA's

generally applicable radiation protection standards apply to protection of members of the public,

they are coordinated with requirements promulgated by NRC and the States.

DeDartment of Enerav (DOE) Radiation Protection Programs and Reguirements

The DOE's 10 CFR 835, 0Occupational Radiation Protection,' provides nuclear safety

requirements that, if violated, provide a basis for the assessment of civil and criminal penalties.

The DOE has a series of guides, standards, programs, and orders which are consistent with

10 CFR 835. The DOE's Office of Health and Safety estabilshes comprehensive and integrated

programs for the protection of workers from hazards in the workplace, including ionizing

radiation. The DOE has standard radiation dose limits which establish maximum permissible

doses to workers and members of the public. DOE radiation protection standards are based on

EPA 1987 guidance, which in turn is based on recommendations from the Intemational

Commission on Radiological Protection (1977) and the National Council on Radiation Protection

and Measurements (NCRP) (1987). In addition to the requirement that radiation doses not

exceed the limits, contractors are required to maintain ALARA exposures.

According to DOEIEH-0688, 'DOE Occupational Radiation Exposure 2003 Report,'

The change in operational status of DOE facilities has had the largest impact on

radiation exposure over the past 5 years due to the shift In mission from production to

cleanup activities and the shutdown of certain facilities. For 2003, this resulted in an

Increase in the collective dose as sites handled more radioactive materials for

processing, storage, or shipping.

In this document, DOE also stated that a statistical analysis of data over the past 5 years

indicates 'that while the collective TEDE, neutron, and extremity dose increased between 2002

to 2003, it does not represent a statistically significant change in the dose received by individual

workers at DOE.'

Other Date Sources

ACNW considered several databases:

Specific information related to incidents in Agreement and non-Agreement States was

included from the NRC's nuclear materials events database (NMED),

http://www.nmed.il.gov.

State radiation control programs most often integrate regulation and control of ionizing

radiation and radioactive material not regulated by NRC under the Atomic Energy Act

-2-
(as amended). Sources of information Include the Conference of Radiation Control

Program Directors (CRCPD) chttp:flwww.crcpd.org> and the Organization of Agreement

States (OAS) chttp:Ilwww.agreementstates.org>.

Recent examples of emerging guidance Include: the work cosponsored by the Center

for Devices and Radiological Health (CDRH) and the Transportation Security

Administration (TSA) and performed by the NCRP. This work Is reported in the

OPresidential Report on Radiation Protection and Advice: Screening of Humans for

Security Purposes Using Ionizing Radiation Scanning Systems.' The report will be

completed and delivered to CDRH this summer. The CDRH intends to use the NCRP

recommendations as guidance when considering new performance standards. The

CDRH also Is working with other government agencies and the American National

Standards Institute Committee (ANSI) N43 to identify new consensus standards for

cargo and vehicle scanners that use Ionizing radiation.

* The National Academy of Sciences recently released its BEIR Vil report'Health Risks

from Exposure to Low Levels of ionizing Radiation,' which provides an update to health

risks related to radiation. The report affirms that current cancer risk estimates have not

changed significantly from earlier estimates.

* The 2003 DOE Occupational Radiation Exposure Report provides a summary and

analysis of the occupational radiation exposure received by individuals associated with

DOE activities.

OSHA-NRC Memoranda of Understandinc

There are four Memoranda of Understanding (MOU) between OSHA and NRC.

1. STD 01-04-001 - STD 1.4.1 OSHA Coverage of lonizina Radiation Sources Not

Covered by the Atomic Energy Act 10-30-1978. This early memorandum recognizes

the U.S. Atomic Energy Commission (AEC) authority to regulate source, by-product, and

certain special nuclear materials, and that OSHA's authority to regulate radiation

sources does not Include those regulated by AEC. It further states that OSHA covers all

radiation sources not regulated by AEC, such as X-ray equipment, accelerators,

accelerator-produced materials, electron microscopes, betatrons, and some naturally

occurring radioactive materials.

2. CPL 02-00-086 - CPL2.86 - Memorandum of Understanding Between OSHA and

MMB. This memorandum characterizes NRC-licensed nuclear facility hazards into four

categories:

* Radiation hazards produced by radioactive materials;

* Chemical hazards produced by radioactive materials;

* Plant conditions which affect the safety of radioactive materials and thus present an

increased radiation hazard to workers; and

-3-
* Plant conditions which result in occupational hazards, but do not affect the safety of the

licensed radioactive materials.

This MOU delineates the general areas of responsibility of each agency, describes

generally the efforts of the agencies to achieve worker protection at facilities licensed by

NRC, and provides guidelnes for coordination of interface activities between OSHA and

NRC. To insure against gaps in the protection of workers and avoid duplication of effort,

the MOU acknowledges NRC jurisdiction over the first three hazards and OSHA over the

fourth hazard.

3. Worker Protection at Facilities Licensed bythe NRC 11-16-1998. This MOU

describes the efforts of the agencies to achieve worker protection at facilities licensed by

NRC and provides guidelines for coordination of interface activities between OSHA and

NRC. The accord replaced existing guidelines which had been used to coordinate

activities of the two agencies. OSHA wil provide NRC information, based on reports of

injuries or complaints, about nuclear power plant sites where Increased management

attention to worker safety Is needed. OSHA also wiD give training In basic chemical and

industrial safety to NRC Inspection personnel so that they will be able to better identify

matters of concern to OSHA in radiological and nuclear inspections. The NRC will

provide training In radiation safety to those OSHA and State program personnel who

may participate in joint evaluation of safety hazards in some facilities.

4. Gaseous Diffusion Plant Sites. The AEA, as amended, created the United States

Enrichment Corporation (USEC), to manage and operate the two uranium gaseous

diffusion enrichment plants in Paducah, Kentucky, and Piketon, Ohio. The AEA requires

USEC to be subject to and comply with the Occupational Safety and Health Act, and

with applicable NRC standards for radiological safety and common defense and security.

Furthermore, the USEC Privatization Act requires NRC and the OSHA to enter into a

memorandum of agreement to coordinate their regulatory programs to assure worker

safety, avoid regulatory gaps in the protection of workers, and avoid duplicative

regulation.

-4-
UNITED STATES

NUCLEAR REGULATORY COMMISSION

ADVISORY COMMITTEE ON NUCLEAR WASTE

WASHINGTON. D.C. 20555-001

eptarba 29, 2005

The Honorable Nils J. Diaz

Chairman

U.S. Nuclear Regulatory Commission

Washington, D.C. 20555-0001

SUBJECT: REVIEW OF STAFF'S PRECLOSURE REVIEW PREPARATIONS FOR THE

PROPOSED YUCCA MOUNTAIN REPOSITORY

Dear Chairman Diaz

At Its 1 62n' meeting on August 2-4, 2005, the Advisory Committee on Nuclear Waste (ACNW)

heard a presentation by the Nuclear Regulatory Commission (NRC) staff on "Status of Yucca

Mountain Preclosure Review Preparations." The following are our observations and

recommendations regarding the staff's preparations to meet the challenge of this risk-informed,

performance-based review.

Background

The NRC staff has undertaken a number of activities to prepare for its review of preclosure

design aspects of the license application for the proposed Yucca Mountain repository. An

important part of these activities is the organization of review teams for performance

assessment, engineering, site characterization, and health physics. The staff is also developing

a list of risk-significant topics based on the staffs experience and analysis and on information

obtained from visits to relevant fuel-handling facilities. The staff is concentrating on high-risk

topics (including the related uncertainties) and on structures, systems, and components that can

prevent or mitigate the impacts of postulated event sequences.

The staff identified topics for detailed prelicensing review. The topics include aircraft crash

hazard and event sequences, criticality and seismic event sequences, and preclosure safety

analysis. The staff has begun to discuss these topics In a series of technical exchanges with

the U.S. Department of Energy (DOE).

Observations

The NRC staff informed the Committee that preclosure design aspects of licensing are receiving

increased attention and that the staff Is applying necessary resources to address them. 'The

staff is developing guidelines for staff Interaction with DOE on preclosure topics before *he

license application submittal. The Committee agrees with this approach. However, the,

Committee recognizes that the efficiency and effectiveness of the staffs efforts have been

challenged by the apparent lack of completeness and detail in available information on the

design of preclosure systems, processes, facilities, and equipment that are important to

operational safety.
i

-2- SWpnber 29, 2005

The Committee concurs that the staffs initial list of review topics Is appropriate for evaluation.

Additional topics for evaluation are Identified in periodic staff meetings. The Committee

believes iterative preclosure safety assessments and relevant licensing experience (e.g.,

Private Fuel Storage) are potentially useful in Identifying additional topics. The rigor of the

staffs approach to preparing and modifying the list of preclosure focus topics would be easier to

recognize If the staff had a documented basis for the choice of topics (and, as appropriate, a

basis for exclusion of topics).

The Committee believes that lessons learned from other nuclear regulatory licensing experience

could also be a useful source of topics for the staffs preclosure review. For example, human

reliability and fire protection may dominate the risk at both reactor and nonreactor facilities if not

considered early in the design stage. Risk insights indicate that without attention to human

reliability aspects of design and adequate training in the early stages of design, human error

can be a significant contributor to accidents associated with movement of heavy loads at reactor

facilities. A significant number of heavy-load ifts, load manipulations, and movements are

expected to occur during the preclosure operational stage of the repository. They should

therefore be evaluated In the preclosure review. Likewise, costly fire protection retrofitting at

reactor facilities occurred in the past because designers did not have a thorough understanding

early In the design stage of the risk from fire. Fire and smoke propagation can lead to adverse

system Interactions and common-cause failures that may compromise multiple safety barriers.

Another topic deserving attention is equipment and facility aging analysis. The staff informed

the Committee that it plans to consider aging effects in estimating the probability of failure of

equipment Given the lengthy period of operation that the DOE contemplates for the preclosure

facility, these effects could be significant, although difficult to quantify. The Committee also

notes that reliability goals for important preclosure equipment such as have been established for

safety-significant reactor equipment could be a significant enhancement to preclosure safety.

Recommendations

The NRC staff should develop a documented, risk-informed process for identifying topics

that the staff will focus on in reviewing preclosure aspects of the proposed Yucca

Mountain repository. Iterative safety assessments could be a useful tool in such a

process.

Z.

3.

4.

nhe stan snoula ada numan reliabily analysis and Tire protection to me 11st o0 nigh- priority preclosure review topics.

The staff should assess DOE's reliability targets for systems and components important

to safety and those factors that impact reliability during the preclosure period (e.g.,

design configuration, operation, equipment and facility aging, surveillance, and

maintenance).

To increase the efficiency and effectiveness of its preparations for a risk-informed

performance-based review, the staff should continue to seek detailed information from

DOE on preclosure design.
;

-3- Septenber 29, 2005

We look forward to hearing from the staff again on the subject of preclosure safety assessment

at a mutually convenient future date.

Sincerely,

77"-

Michael T. Ryan

Chaimman
I

UNITED STATES

NUCLEAR REGULATORY COMMISSION

ADVISORY COMM'TTEE ON NUCLEAR WASTE

WASHINGTON, D.C. 20555-0o01

Septerbe 30, 2005

The Honorable Nils J. Diaz

Chairman

U.S. Nuclear Regulatory Commission

Washington, D.C. 20555-0001

SUBJECT: COMMENTS ON USNRC STAFF RECOMMENDATION OF THE USE OF

COLLECTIVE DOSE

Dear Chairman Diaz:

On July 20,2005, staff from the Office of Nuclear Regulatory Research briefed the Committee

regarding proposals on effective and realistic uses of the concept of collective dose In radiation

dose analysis.

The staff reported they are considering four options (one with three variations) regarding the

uses of collective dose. These options as reported are as follows.

Option 1-Truncate individual doses at some nominal value.

* Truncate Individual doses at some nominal value from the collective dose calculation.

* Truncate Individual doses at some distance from a facility or at some future time.

Option 2-Health Physics Society position on collective dose

* For populations in which almost all individuals are estimated to receive a lifetime dose of

less than 10 rem above background, collective dose is a highly speculative and an

uncertain measure of risk and should not be used for the purpose of estimating

population health risks [Radiation Risk in Perspective (position statement of the Health

Physics Society), 1996, revised in 2004].

* Estimation of health risk associated with radiation doses that are of similar magnitude as

those received from natural sources should be strictly qualitative and encompass a

range of hypothetical health outcomes, including the possibility of no adverse health

effects at such low levels.

Option 3-individual dose emphasis

* Emphasizes protection of individuals in the critical group of an exposed population and

assumes that If the average Individual in the critical group is protected, the entire

population is protected.

* Consistent with the 10 CFR Part 20 Subpart E, Radiological Criteria for License

Tennination Rule," which explicitly states that the average individual of the critical group

must be below a 25 mrem per year dose constraint and ALARA.
i

-2- Septeater 30, 2005

* No collective dose is calculated in this option.

Option 4-Significance determination of a collective dose calculation

* Use a Commission-approved criterion to judge the significance of a collective dose

calculation.

Option 4a: I mrem per year and 100 person-rem per year

* International bodies argue that It is not cost-beneficial to do a formal cost-benefit

analysis process when individual and collective doses are less than 1 mrem per year

and 100 person-remn per year, respectively, and the practice can be exempted from

regulatory oversight (IAEA 1996, ICRP 1992, EC 1999).

Option 4b: Background collective radiation dose comparison

* Compare the collective dose from a regulated activity to the collective dose from

background radiation to the same population.

* This approach is comparable to the approach in NUREG-1515, Standard Review Plans

for Environmental Reviews for Nuclear Power Plants.-

Option 4c: Safety goal evaluation

* Expand the use of the reactor safety goal/quantitative health objective value for latent

cancer fatalities of 0.1% of the sum of cancer fatality risks resulting from all other

causes to other applications that use collective dose.

* The staff would compare collective dose calculations to this safety goal value, either in

units of person-rem or in latent cancer fatality risk, and make a determination of "not a

significant additional risk.

Observations and Recommendations

The Committee believes that collective dose has little value In an absolute sense. Irrespective

of whether very low doses can be reliably measured or estimated, the product of an individual

dose and a population magnitude does not yield a number that has any real meaning. When

estimates of risk are desired, the Committee recommends use of Individual risk within the

context of the critical group or the reasonably maximally exposed individual (RMEI) scenario.

However, the Committee does believe that collective dose is useful for comparing different

management options (e.g., steps taken under ALARA to reduce radiation doses to workers).

The Committee believes that there is no basis for truncating dose at some nominal value when

calculating collective dose.
-3- Septebt- 30, 2005

Given the Inherent limitations of collective dose and the serious potential for misuse (e.g., using

collective dose as a measure of risk), the Committee does not recommend adoption of any of

the options considered above.

Sincerely,

Michael T. Ryan Chairman
REVIEW OF SELECTED

NRC RESEARCH AND

TECHNICAL

ASSISTANCE

Ruth F. Weiner
Recent Activities

* Visited Center for Nuclear Waste

Regulatory Analyses (April 2005)

* Briefing by RES on waste-safety

research program (July 2005)

* Briefing by RES on reactive

transport programs (November

and December 2005)

14
* Reported on RES-sponsored work

on groundwater discharge (April

2005)

* Reported on CNWRA programs

(August 2005)

* Reported on CNWRA igneous

activity work (December 2005)

* Reported on RES-sponsored

programs (December 2005)

15
2005 CNWRA Visit Topics

* Igneous activity

* Container life and source term

* Codes and models for complex

decommissioning sites

* Radionuclide retardation

16
CNWRA Programs

* Strong programs in the areas of

container life and source term

characterization

* Results to date include:

- Characterization of the passive

film in Alloy 22

- Quantification of the behavior of

localized corrosion and corrosion

inhibilotrs

- Evaluation of the impact of spatial

water chemistry on sorption

17
RES-Sponsored Work

* High-quality work with limited

funding

* Effectiveness of the programs

enhanced by cooperative

arrangements with national and

international research

organizations

* Joint working groups are planned

18
RES-Sponsored Work

Future Activities

* Review of Package Performance

Study protocols

* Joint working groups, as

appropriate

II . . i- = .,-

19
i

ACNW LETTERS
UNITED STATES

NUCLEAR REGULATORY COMMISSION

ADVISORY COMMIfTEE ON NUCLEAR WASTE ACNWR-0225

WASHINGTON, DC 20555 . 0001

August 3, 2005

The Honorable Nils J. Diaz

Chairman

U.S. Nuclear Regulatory Commission

Washington, D.C. 205550001

SUBJECT: REPORT ON SELECTED NRC-SPONSORED TECHNICAL ASSISTANCE

PROGRAMS AT THE CENTER FOR NUCLEAR WASTE REGULATORY

ANALYSES

Dear Chairman Diaz:

During the past 16 months the Advisory Committee on Nuclear Waste (ACNW) has written five

letters to the Commission describing results of the ACNW's continuing oversight of the Nuclear

Regulatory Commission's (NRC's) regulatory technical assistance and research programs. The

topics discussed were selected programs of the Center for Nuclear Waste Regultory Analyses (CNWRA) (March 4, 2004), radionuclide transport (May 5, 2004), uranium dioxide solubility (July 6, 2004), model uncertainty (August 4, 2004), and groundwater recharge (April 27, 2005).

The ACNW also briefed the Commission on the research program on March 16, 2005.

As part of the Committee oversight, three members of the ACNW led a focused discussion of

selected-technical assistance topics on April 13-15, 2005 at the CNWRA in San Antonio, Texas.

Two ACNW consultants supported these members. The Technical Director of the CNWRA had

previously provided the ACNW team an overview of the accomplishments of the CNWRA and

future projects during the 157th ACNW meeting in February 2005. The team focused its April 2005 discussions on activities addressing topics likely to be important in evaluating a license

application for a potential repository at the Yucca Mountain site and of particular interest to the

ACNW.

This letter, the first of two addressing topics discussed during the April 2005 visit, deals with the

CNWRA work on corrosion, radionuclide mobility, and performance assessment modeling. A

second letter will address analysis of a potential igneous event at Yucca Mountain and its

possible consequences.

Summary of the team's Yucca Mountain-related observations:

(1) The presentations on container life, the radionuclide source term, the near-field

environment, radionuclide retardation, and the published versions of the Department of

Energy's Total System Performance Assessment were comprehensive and illustrated

the strength of the CNWRA in these areas.

(2) The CNWRA has made significant progress in ongoing work directed at understanding the controls and the processes involved In container corrosion. Laboratory corrosion

studies include stress corrosion cracking resistance of Alloy 22, high-level waste lass

dissolution processes, mechanical properties of the waste package, and the relationship

between in-package chemistry and package corrosion. The laboratory studies show

that corrosion by chloride-containing solutions can be inhibited by appropriate ratios of

certain anion concentrations. Studies of Yucca Mountain dust within the waste

emplacement drifts indicate that nitrate and sulfate are present in sufficient
a

-2-

concentration to potentially inhibit corrosion. The results of corrosion rate studies are

expressed as distributions that incorporate uncertainty in corrosion rates. The

CNWRA's humidity deliquescence studies show that, although chloride deliquescence could form corrosive brine, other components of this dust can inhibit such corrosion.

The CNWRA is abstracting these results for incorporation in the ongoing model

development activities.

(3) Regarding spent fuel dissolution studies in support of the total-system performance assessment, the CNWRA staff is using parameter values from the technical literature

and results from laboratory experiments to model the dissolution of radionuclides from

spent fuel. These studies have shown that fuel bumup does not significantly influence

dissolution of the uranium dioxide matrix.

(4) The CNWRA has been responsive to the suggestions made during the ACNW's

Geosphere Transport Working Group meeting (ACNW letter to Chairman Diaz dated

August 3, 2004). Potential spatial water chemistry impacts on sorption have been

evaluated. Additional experiments are underway to determine neptunium sorption in the

alluvium. Retardation in the alluvium can provide a barrier to radionuclide migration, and understanding the spatial variability of retardation reduces uncertainty.

(5) The CNWRA is currently evaluating improvements in the modeling of phenomena such

as tephra remobilization, consequences of drift degradation, drip shield and waste

container weld corrosion, and colloid transport. Furthermore, numerous parameter values and their distributions reflect recent progress in the understanding of relevant

features, events, and processes (FEPs). This work is ongoing and is expected to lead

to improvements in evaluation of the risk associated with the FEPs involved in the

performance of the proposed repository.

(6) The CNWRA has ongoing programs that address the frequency, consequences, and

potential health effects that are associated with igneous activity, and will publish a

number of letters in the next several months. The ACNW will continue to interact with

the NRC staff on this subject and will provide a letter to the Commission in the near

future.

The CNWRA reported to the ACNW team on Its evaluation of models and codes for use in

pathway dose assessment for complex decommissioning applications and expects to complete

a final letter in October 2005. The ACNW plans to review this work when it is completed.

The ACNW will continue its dialog and meetings with the NRC and CNWRA staffs and will keep the Commission apprised of our view of the progress of this work.

Sincerely,

Michael T. Ryan Chairman
. - .

-2-

concentration to potentially inhibit corrosion. The results of corrosion rate studies are

expressed as distributions that incorporate uncertainty in corrosion rates. The

CNWRA's humidity deliquescence studies show that, although chloride deliquescence could form corrosive brine, other components of this dust can inhibit such corrosion.

The CNWRA is abstracting these results for incorporation in the ongoing model

development activities.

(3) Regarding spent fuel dissolution studies in support of the total-system performance

assessment, the CNWRA staff is using parameter values from the technical literature

and results from laboratory experiments to model the dissolution of radionuclides from

spent fuel. These studies have shown that fuel bumup does not significantly influence

dissolution of the uranium dioxide matrix.

(4) The CNWRA has been responsive to the suggestions made during the ACNW's

Geosphere Transport Working Group meeting (ACNW letter to Chairman Diaz dated

August 3, 2004). Potential spatial water chemistry impacts on sorption have been

evaluated. Additional experiments are underway to determine neptunium sorption in the

alluvium. Retardation in the alluvium can provide a barrier to radionuclide migration, and understanding the spatial variability of retardation reduces uncertainty.

(5) The CNWRA is currently evaluating improvements in the modeling of phenomena such

as tephra remobilization, consequences of drift degradation, drip shield and waste

container weld corrosion, and colloid transport. Furthermore, numerous parameter values and their distributions reflect recent progress in the understanding of relevant

features, events, and processes (FEPs). This work is ongoing and is expected to lead

to improvements in evaluation of the risk associated with the FEPs involved in the

performance of the-proposed repository.

(6) The CNWRA has ongoing programs that address the frequency, consequences, and

potential health effects that are associated with Igneous activity, and will publish a

number of letters in the next several months. The ACNW will continue to Interact with

the NRC staff on this subject and will provide a letter to the Commission in the near

future.

The CNWRA reported to the ACNW team on Ks evaluation of models and codes for use in

pathway dose assessment for complex decommissioning applications and expects to complete

a final letter in October 2005. The ACNW plans to review this work when It is completed.

The ACNW will continue its dialog and meetings with the NRC and CNWRA staffs and will keep the Commission apprised of our view of the progress of this work.

Sincerely,

Michael T. Ryan Chairman

DOCUMENT NAME: E:.FilenetIML0521 50286.wpd To receive a copy of this document, Indicate In the box: OC" s Copy without attachmentlenclosure *E" a

Copy with attachmentlenclosure "N" r No copy 'See previous concurrence Accession #: ML052150286

OFFICE ACRSIACNW Y AACNW CNW Y ACRS/ACNW Y AC W Y ACNW Y

NAME RSavio I MScott I AThadani | JLark n_ I MTRyan

DATE 07129105 * 08102105 10803105 08103/05 108103105

OFFICIAL RECORD COPY
UNITED STATES

NUCLEAR REGULATORY COMMISSION

ADVISORY COMMITTEE ON NUCLEAR WASTE

WASHINGTON. D.C. 205

April 27,2005

The Honorable Nils J. Diaz

Chairman

U.S. Nuclear Regulatory Commission

Washington, DC 20555-0001

SUBJECT: BRIEFING ON RES-USDA RESEARCH: ESTIMATING GROUND

WATER RECHARGE AND EVALUATING MODEL ABSTRACTION

TECHNIQUES

Dear Chairman Diaz:

During bts I5Be meeting on March 15-17, 2005, the Advisory Committee on Nuclear

Waste heard presentations from the Office of Nuclear Regulatory Research and the

Agriculture Research Service of the U.S. Department of Agriculture (USDA) about their

research on estimating groundwater recharge and evaluating model abstraction

techniques. The main thrust of the research Is to develop insights leading to (a) better

understanding of near surface water movement, saturated zone recharge, and solute

transport at sites with complex processes and features, and (b) guidelines on selecting

models that are as simple as possible but are realistic enough to provide a basis for

risk-informed decisionmaking. The Committee believes that this research should

continue.

The Committee learned about work that Is being done to evaluate model abstractions of

subsurface water flux and pathways at a highly instrumented, densely sampled

watershed-scale site operated by the USDA in Beltsvilie, MD. This work builds on

earlier experiments conducted in well-controlled environments. Ground-penetrating

radar coupled with soil moisture measurements has been used successfully at the

Beltsville site to identify the location of preferred subsurface pathways that are

important to the assessment of uncertainty in infiltration and groundwater recharge

estimation.

This research shows:

Infiltration and groundwater recharge can be better understood using the

methodology developed in this research. Models used to predict the fate and

transport of contaminants in subsurface environments are sensitive to these

parameters.
4.

-2-

These field tests can be used to evaluate alternative conceptual models and

improve the selection of the best model abstraction.

The Beltsville facility provides the opportunity for large-scale field testing in a

highly Instrumented environment. The research setting permits realistic

estimates for sites similar in hydrology and subsurface geology to Beltsville

through the incorporation of dynamic hydrologic processes.

The Committee offers the following conclusions and recommendations:

* Continued collaboration between the NRC and the USDA Is a cost-effective way

to participate In high quality research that Is relevant to NRC needs. The

Committee noted that the cost to NRC to date has been approximately 2% of the

total cost.

* The Committee believes that this collaborative research program is Important

because It Is aimed at reducing model complexity and assessing uncertainty

while maintaining realism and the ability to support risk-informed decislonmaking.

* Both the field studies and the model abstraction research appear to have

important applications in the areas of site characterization, flow and contaminant

transport modeling, performance assessment, contaminant isolation technology

evaluation, the design of monItoring programs, and uncertainty assessment.

* The Committee encourages the research staff to develop strategies to enable

the transfer of results from studies at Beltsville to other hydrologic environments.

* LThe Committee believes the Beltsville research program should be coordinated

with similar programs. For example, field-scale hydrologic research is being

conducted at DOE facilities in Washington (Hanford) and New Mexico (Sandia) and at the University of Arizona's Maricopa site. Experience from these other

sites should allow extension of the methodology developed In this research.

Sincerely,

Michael T. Ryan

Chairman
WASTE

DETERMI NATION

ACTIVITI ES

Allen G. Croff
*

Objectives

* Provide advice on the Standard

Review Plan so that its use in

reviewing waste determinations

will be risk informed

* Evaluate emerging technologies

and approaches related to waste

determination

21
FY 2005 Activities

* NMSS presentation (November 2004)

* Attended interagency workshop on

cement materials performance

(June 2005)

* Organized public waste

determination working group

meeting (August 2005)

* Savannah River site visit (August

2005)

* Attended tank waste retrieval

technology demonstration

(September 2005) 22
FY 2006 Activities to Date

* Attended NAS meeting on the

performance of engineered

barriers (October 2005)

* West Valley ACNW meeting

(October 2005)

* Attended NMSS Standard Review

Plan public scoping meeting

(November 2005)

* Letter on Standard Review Plan

(December 2005) 23
Standard Review Plan-I

* Single document integrating all criteria

* Consistent, risk-informed interpretation

of waste determination criteria

* Evaluate adequacy of radionuclide

removal and ALARA in context of

surrounding risk

24
Standard Review Plan-ll

* Anticipate improvement in

radionuclide removal technology

* Encourage risk-informed

performance assessment

* Expect state-of-the-art monitoring

to be incorporated during design

* Look to NRC regulations and

guidance on similar subjects for

insights

25
Planned Activities

* Review draft Standard Review

Plan

* Working group meeting on cement

performance (engineered barriers)

* Review implementation of

Standard Review Plan

* Other activities as requested by

the Commission

26
S

ACNW LETTERS
- .

NU A UNITED STATES

NUCLEAR REGULATORY COMMISSION

ADVISORY COMMITTEE ON NUCLEAR WASTE

WASHINGTON, D.C. 20555-0001

December 9, 2005

The Honorable Nils J. Diaz

Chairman

U.S. Nuclear Regulatory Commission

Washington, D.C. 20555-0001

SUBJECT: DEVELOPMENT OF A STANDARD REVIEW PLAN FOR U.S. DEPARTMENT

OF ENERGY WASTE DETERMINATIONS

Dear Chairman Diaz:

The U.S. Department of Energy (DOE) is expected to pursue a number of determinations that

certain wastes are not high-level waste as a prerequisite to allowing disposal. DOE is required

or expected to request that the U.S. Nuclear Regulatory Commission (NRC) perform technical

reviews of the Department's waste determinations and, In some cases, its disposal and

monitoring plans for the wastes.' The NRC staff Is currently developing a Standard Review

Plan (SRP) for these reviews. In this letter the Advisory Committee on Nuclear Waste provides

its recommendations on the development of the SRP based on Information obtained from the

following activities:

* The Committee held a 2-day public working group meeting on waste determination

August 2 - 3, 2005, during its 162nd meeting. The working group meeting included

background presentations by DOE and NRC staff; 12 presentations by experts from

academia, research institutions, and private enterprise; three panel discussions

involving these same experts-and staff from the NRC Office of Nuclear Regulatory

Research; and input from State agencies and public stakeholders.

* Three Committee members, ACNW staff, the Director of the Division of Waste

Management and Environmental Protection in the Office of Nuclear Material Safety and

Safeguards (NMSS), and a member of the public made a 1-day visit to the Savannah

River Site (SRS) on August 10, 2005. They toured the tank farms, tank waste

processing facilities, waste vitrification facilities, and equipment development facilities.

The participants also benefitted from formal and informal discussions with SRS staff

about their approach to tank cleanup and waste determinations.

* Members of the Committee, ACNW staff, and NRC staff toured the West Valley

Demonstration Project (WVDP) site, participated in a working group meeting, and heard

input from the public on October 18 - 20, 2005.

'Section 3116 of the Ronald Reagan National Defense Authorization Act (NDAA) of

Fiscal Year 2005 (Public Law 108-375-October 28, 2004) makes the NRC responsible for

providing technical consultation to DOE on waste determinations in the States of South

Carolina and Idaho and, in coordination with the concerned State, for monitoring DOE disposal

actions.
4 i

-2- December 9, 2005

* A Committee member who is also a member of a National Research Council committee

addressing issues related to waste determinations visited DOE's tank waste storage

sites at SRS, Hanford, and Idaho National Laboratory.

* An ACNW staff member attended a demonstration of waste retrieval technologies in

Mooresville, North Carolina on September 7, 2005.

* An ACNW staff member attended a briefing to the National Research Council's Nuclear

& Radiation Studies Board on previous and ongoing studies of issues related to waste

determinations held in Washington, D.C., on September 12, 2005.

Based on the information obtained from these activities, the Committee developed the

observations and recommendations provided in this letter. The observations and

recommendations are organized as follows:

* Section 1 concerns the overall scope of the SRP.

* Section 2 addresses the overall consistency among criteria for waste determinations as

well as the consistency of performance objectives and key phrases in the criteria, and

the consistency of the criteria with other NRC regulations and guidance.

* Section 3 provides insights concerning evaluation of two key components of waste

determinations: the status of radionuclide removal technology and performance

assessment.

* Section 4 addresses how to evaluate whether wastes have been removed to the

amaximum extent practical and whether doses are "as low as reasonably achievable

(ALARA).

* Section 5 addresses technical considerations regarding NRC guidance on monitoring of

waste determined to not be high-level waste to assess compliance with the performance

objectives of Subpart C to 10 CFR Part 61.

1. STANDARD REVIEW PLAN SCOPE

The principal purposes of an SRP are to enhance the quality and uniformity of staff reviews and

to present a well-defined base from which to evaluate proposed changes in the scope and

requirements of reviews. The NRC has experience in developing and Implementing SRPs In

program areas related to waste determination reviews. The most relevant technical information

can be found In NUREG-1200, Standard Review Plan for the Review of a License Application

for a Low-Level Radioactive Waste Disposal Facility," Revision 3, April 1994; NUREG-1757,

Consolidated NMSS Decommissioning Guidance," September 2003 along with draft

Supplement 1, issued for public comment in September 2005; and NUREG-1 573, 'A

Performance Assessment Methodology for Low-Level Radioactive Waste Disposal Facilities:

Recommendations of NRC's Performance Assessment Working Group," October 2000.
.3. December 9, 2005

Guidance on risk-informed, performance-based approaches helpful to the development of the

SRP can be found in NUREG-1549, *Decision Methods for Dose Assessment to Comply with

Radiological Criteria for License Termination-Draft Report for Comment," July 1998, and the

June 1998 SRM-SECY-98-144 on the staffs white paper on risk-informed and performancebased regulation.

Developing the SRP for waste determinations is complicated by the diversity of radioactive

materials to be considered, the existence of multiple sets of criteria for developing and

reviewing waste determinations, and the NRC's role as consultant instead of statutory regulator.

Recommendation: The SRP should be a single document that provides integrated guidance to

NRC staff on risk-Informed reviews of waste determinations and implicit guidance to DOE on

the information to be provided in the waste determination. The waste determination SRP

should build on the generic format, content, and Implementation of existing SRPs and on

relevant information in existing SRPs. The Committee believes the integration will enhance

uniformity and efficiency of the reviews.

2. CONSISTENCY

2.1 Criteria for Determinating of Waste Classification

The criteria for preparing and reviewing a waste determination depend on the specific waste

and site:

* Section 3116 of the NDAA is applicable to some waste determinations at Savannah

River and Idaho.

* NRC Decommissioning Criteria for the West Valley Demonstration Project (M-32) at the

West Valley Site, Final Policy Statement [64 FR 67952, December 3, 1999] are

applicable to some waste determinations there.

* DOE Order 435.1, Radioactive Waste Management," and the supporting documents

DOE M 435.1-1, "Radioactive Waste Management Manuals and DOE Guide 435.1-1,

Implementation Guide for use with DOE Manual 435.1-1," issued in 1999 and reissued

in 2001, may be used as a basis for some waste determinations.

Recommendation: The SRP should adopt a consistent technical interpretation of similar criteria

in the three sets of criteria.

2.2 Subpart C Performance Objectives

The Committee notes that under Section 3116 NRC staff must review waste determinations to

assess conformance with 10 CFR Part 61 Subpart C performance objectives. The other two

sets of criteria allow disposal to meet safety objectives comparable to the objectives stated in

Subpart C. The Committee believes that the SRP should focus on confirming that DOE's

proposed safety objectives are essentially identical to those in Subpart C.
A

-4. December 9, 2005

Recommendation: The SRP should accept use of Subpart C performance objectives per se in

all sets of criteria. If DOE chooses to use a different set of objectives, the SRP should expect

DOE to provide a compelling technical justification to show that the objectives are as protective

as those in Subpart C.

2.3 "Highly Radioactive" and "Key" Radionuclides

DOE Manual 435.1 and the WVDP criteria use the phrase "key radionuclides' in addressing

radionuclide removal, whereas the Section 3116 criteria use the phrase 'highly radioactive

radionuclides." 'Highly radioactive commonly refers to relatively short-lived radionuclides,

particularly If they emit penetrating radiation. The Committee notes that this common

interpretation would not lead to a risk-informed approach because (a) it excludes long-lived

radionuclides that should be removed to the maximum extent practical because they are

important to risk in many situations (e.g., Tc-99, Np-237) and (b) it is based on an inherent

property of a radionuclide (its decay characteristics) Instead of the risk posed by the waste of

which the radionuclide Is a part. The Committee believes a risk-informed interpretation of

highly radioactive' and ukey' radionuclides can best be accomplished by analyzing the results

of a risk-informed performance assessment for the radionuclides that are the dominant

contributors to dose.

Recommendation: The SRP should adopt a risk-informed interpretation of 'highly radioactive

radionuclides" by defining It to mean the same as 'key radionuclides," i.e., radionuclides

potentially Important to meeting the Subpart C performance objectives.

2.4 Other NRC Regulations and Guidance

After removal, processing, and conversion to a solid form, tank waste will be disposed of in

much the same way as is waste at a commercial low-level waste (LLW) disposal facility. A

grout and cap approach is typically planned for in-place isolation of residual waste in tanks.

This approach has similarities to site decommissioning. Existing NRC regulations and guidance

In these two areas reflect years of experience. Examples of such guidance documents for

performance assessments are NUREG-1573, NUREG-1 757, and NRC staff 'Technical Position

on Waste Form", Revision 1, January 1991.

Recommendation: Existing NRC regulations and guidance documents should be used as a

source of insights for developing the SRP.

3. TECHNOLOGY AND PERFORMANCE ASSESSMENT

3.1 Technology for Removal of Radionuclides

The Committee notes that DOE has many waste retrieval and radionuclide separation

technologies available and has been relatively successful in its completed retrieval efforts.

However, the Committee believes DOE will continue to face technical challenges in

radionuclide removal because it has retrieved only a small portion of the waste that will

eventually require retrieval and most of this waste has been retrieved from DOE's less complex

tanks. Furthermore, DOE has separated radionuclides from only a fraction of the retrieved

waste. The Committee observes that DOE continues to improve its radionuclide removal
*

.5- December 9, 2005

technologies and adopt new technologies to address challenges as they arise.

Recommendation: The NRC staff should review the approaches to waste retrieval and

radionuclide separation in each waste determination in the context of relevant existing and

projected technologies. The staff should expect DOE to have considered existing relevant

technologies or technologies being developed by domestic and international organizations.

3.2 Performance Assessment

Historically, variability and uncertainty In performance assessments for near-surface waste

disposal were addressed by selecting one or two different values for parameters believed to be

important and observing how much the estimated dose from a detemninistic performance

assessment changes. Exclusion of probabilistic performance assessments has been justified

by using conservative approaches in the deterministic performance assessment.

The Committee believes that assumptions such as the duration of effective Institutional controls

and selection of conceptual models such as those for groundwater flow can dominate the

magnitude of the estimated dose from near-surface waste disposal facilities. Many

assumptions such as those about institutional control cannot be validated because they involve

predictions of the future behavior of people and there is a growing body of literature citing

experience which raises concerns about the reliability of such controls. Conceptual models of

physical systems are theoretically amenable to validation through analysis or testing, but many

situations are so complex that validation may not be practical.

The Committee notes the extensive use of cementitious materials as structural barriers and

solid matrixes for isolating, in near-surface disposal facilities, wastes determined to not be highlevel waste. Assumptions about the rates at which the beneficial properties of cementitious

materials degrade are therefore important to the results of performance assessments for such

facilities.

Recommendation: The SRP should specify a preference for probabilistic performance

assessments using best estimates with explicit analysis of uncertainties. Exceptions should

include documentation of how uncertainties were addressed.

Recommendation: The SRP should recognize that some Important performance assessment

assumptions are incapable of validation. Such assumptions should be based on realistic

consideration of empirical evidence to the extent such evidence exists and should be subjected

to uncertainty analyses.

Recommendation: The SRP should provide guidance to the NRC staff on reviewing

improvements in technical bases for assumptions concerning the long-term degradation rate of

cementitious materials in waste disposal applications. The NRC staff should maintain the

capability to review justifications for performance assessment assumptions based on cuttingedge research concerning cementitious materials.
I i X

-6- December 9, 2005

4. "MAXIMUM EXTENT PRACTICAL" AND ALARA

All three sets of criteria require that the amount of radionuclides In a waste be reduced to the

maximum extent practical" or the "maximum extent technically and economically practical," and

that doses to workers or the public be ALARA. All of these goals are functionally the same:

they require that factors such as the capability of technologies, costs, and risks associated with

competing radionuclide removal alternatives be evaluated as a basis for deciding how much risk

reduction (i.e., waste retrieval and processing, and use of engineered barriers) is enough. The

potential importance of risks posed by other nearby waste disposal areas and contaminated

environmental media is a factor to be considered in making this decision.

The Committee observes that complex decisions are likely to require consideration of

stakeholder values and demands as well as technical Issues. The waste determination

decisionmaking process and the process for developing the SRP should be transparent and

allow stakeholder participation. The November 10, 2005, NMSS public scoping meeting2 to

obtain input on the development of the SRP, was a good start toward achieving this goal.

Recommendation: The Information necessary to support DOE's determination that

radionuclides have been removed to the maximum extent practical or maximum extent

technically and economically practical, and that estimated doses are ALARA should be the

same for all sets of criteria.

Recommendation: A risk-informed evaluation of ALARA or radionuclide removal to the

maximum extent practical or maximum extent technically and economically practical should be

done In the context of the surrounding risk.

5. MONITORING TO ASSESS COMPLIANCE WITH PERFORMANCE OBJECTIVES OF

SUBPART C

Under provisions of Section 3116, the NRC, in coordination with the host State, is required to

monitor DOE disposal actions for the purpose of assessing compliance with the Subpart C

performance objectives. The Committee believes compliance monitoring should be considered

in the design of a system to isolate waste and the associated performance assessment. The

Committee further believes that the types and quantities of waste likely to be disposed of onsite

should be considered in selecting monitoring approaches and systems.

Recommendation: NRC staff activities to determine compliance with Subpart C performance

objectives should review the design of barriers to radionuclide release to ensure that provisions

have been made for future monitoring activities. Engineered barrier design has already been

completed for some waste determinations. For these cases, the NRC will have to rely on

reviewing the adequacy of the designs and determining whether improvements are necessary

or feasible.

2 Attended by Committee Vice-Chairman Allen Croff and Committee staff member Latif

Hamdan
f .i

-7- December 9, 2005

Recommendation: Far-field and near-field monitoring, engineered barrier monitoring, and

performance assessment are key elements of performance confirmation. The SRP should

provide guidance to the NRC staff on these topics that includes information on how waste

disposal facilities can be designed to facilitate monitoring.

The Committee looks forward to reviewing the draft SRP as the document evolves. As a result

of the future opportunities for the Committee to provide Its input, it does not expect a formal

response to this letter from NRC staff in favor of allowing them to focus their energies on

preparing the draft SRP.

Sincerely,

Michael T. Rya

Chairman
DECOMMISSIONING

James H. Clarke
Recent Activities

License Termination Rule

* Participated in decommissioning

workshop (April 2005)

* Held working group meeting (June

2005)

* Issued letter on decommissioning

guliance August 2005

28
Committee

Recommendations

* Site-specific factors important for

partial restricted release and

intentional soil mixing

* Long-term control license

preferred over restrictive

covenants

* Additional guidance needed on

use of. engineered barriers and

risk-in ormed decisionmaking

29
0

* "Resident farmer" scenario

only as a screening tool

* Lessons learned--design

with the end in mind

30
-I

West Valley

Demonstration Project

* Working group meeting in October

2005

* Focus on performance

assessment methods

* Received update on site status

* Stakeholder participation

* Issue letter on WVDP (December

2005) 31
West Valley Site

Major Observations and

Recommendations

* The West Valley site provides a

useful model for decommissioning

of complex sites

* Staff approach is technically

sound and enables a risk-informed

review

32
81

* Erosion modeling and analysis will

be critical to remedial decision

making

* Subsurface characterization data

should be used to verify

groundwater modeling

33
Future Activities

* Working group meeting to review

proposed decommissioning

guidance under the License

Termination Rule

* Working group meeting on

modeling and monitoring for

decommissioning activities

34
ACNW LETTERS
NB REG&

UNITED STATES

NUCLEAR REGULATORY COMMISSION

ADVISORY COMMITTEE ON NUCLEAR WASTE ACNWR-0226

WASHINGTON, DC 2055S -0001

August 12, 2005

The Honorable Nils J. Diaz

Chairman

U.S. Nuclear Regulatory Commission

Washington, D.C. 20555-0001

Dear Chairman Diaz:

SUBJECT: DRAFT REVISED DECOMMISSIONING GUIDANCE TO IMPLEMENT THE

LICENSE TERMINATION RULE

The NRC staff is developing revised decommissioning guidance to implement the License

Termination Rule (LTR). In support of this effort, NRC staff and the ACNW (the Committee)

have participated in two meetings. The first was an April 2005 decommissioning workshop

organized by the NRC staff. The entire Committee attended this workshop. The second was a

1-day working group meeting on June 15, 2005, during the 160th meeting of the Committee.

In its working group meeting, the Committee had the benefit of discussions with the NRC staff

and five invited experts selected to provide the perspective of experienced practitioners.'

During the meeting, the Committee provided comments and suggestions that the staff is

considering while developing the draft guidance. Since the staff participated in the working

group meeting and subsequent Committee deliberations, the Committee is confident that its

comments and suggestions have been conveyed.

The working group discussed a range of guidance revisions in several different areas. The

Committee has not seen the revised document since it is still being developed. However,

observations and recommendations that have been discussed with the staff are provided in the

rest of this letter.

OBSERVATIONS AND RECOMMENDATIONS

* The Committee supports the issuance of generic guidance implementing the LTR.

However, site-specific factors are especially important to consideration of partial

restricted release under the long-term control (LTC) license and intentional soil mixing.

X The invited experts were Eric Abelquist, Director of the Radiological Assessments and Training

Program, Oak Ridge Institute for Science and Education; Virgil Autry, Consultant, Department of Health

and Environmental Control, State of South Carolina; Eric Darois, Radiation Safety and Control Services

in New Hampshire; Tracy Ikenberry, Associate and Senior Health Physicist, Dade Moeller & Associates;

and Thomas Nauman, Vice President, Shaw Environmental and Infrastructure.
3f

The Honorable Nils J. Diaz -2-

In these cases, the Committee recommends that the NkbC staff develop criteria and a

demonstration process to enable site-specific decisions on a case-by-case basis.2

* The staff presented an approach to classifying restricted-use sites as either lower or

higher risk and a graded approach to selecting institutional controls. The Committee

believes that this approach is appropriate and risk informed.

* Durable controls will be needed for higher risk restricted-use sites. NRC staff reported

that the guidance will provide two options: an LTC license and a legal

agreement/restrictive covenant (LAIRC) with the NRC. The second option, while

potentially attractive to a site owner, may present uncertainties with respect to the

survivability of the long-term controls. The staff prefers the LTC approach, and the

Committee concurs with this preference.

* The staff asked the Committee for its input on the merits of partial restricted release.

The staff indicated a preference for including the entire site under the LTC license, and

the Committee agrees. However, there may be site-specific factors that merit

consideration, and the Committee recommends a case-by-case approach to partial

restricted release.

* Existing guidance on the use of engineered barriers is limited. The Committee concurs

with the staffs assessment that the agency needs expanded generic guidance on the

barrier design options and more performance experience that can be tailored to specific

sites. The breadth and depth of this guidance should be sufficient to enable riskinformed decisionmaking.

* The staff prefers robust engineered barriers. However, the experience base for the

performance of currently favored designs goes back only a few decades. Very longterm performance (centuries to millennia) has not yet been demonstrated, and there is

no basis for concluding that current systems will perform for very long times without

continuing periodic maintenance. The Committee concurs with the staff's assessment

that monitoring will be needed to confirm performance.

* The Committee recommends that the conventional upper bound resident farmer

scenario be used only as a screening tool and that realistic scenarios be used to

evaluate risk. The revised guidance will address the use of more realistic scenarios for

projected land use. Many decommissioning sites can achieve unrestricted release using

the very conservative and unrealistic resident farmer scenario, but guidance is needed

on more realistic exposure scenarios, especially for complex materials sites.

2 The ACNW recommended a case-by-case approach to requests for Intentional mixing of

contaminated soil in Its letter of July 30, 2004, "Review of the LTR Analysis - intentional Mixing of

Contaminated Soil." The Committee notes that the working group expert panel was divided with respect

to the merits of permitting intentional mixing of contaminated soils.
A

The Honorable Nils J. Diaz -3-

* Groundwater monitoring should be a prime consideration in the revised guidance and

should address ways to determine the requirements for subsurface characterization and

monitoring. The guidance should also address subsurface characterization, monitoring plans, and contingency plans should groundwater contamination occur.

* The Committee recognizes that the lessons learned from decommissioning projects provide valuable information for designing new facilities (designing with the end in mind).

In addition to developing protocols and mechanisms for information collection and

dissemination, the staff will need to devise a process to evaluate the accuracy and

reliability of the information that Is disseminated.

The Committee has participated in the staff's information-gathering activities for the revised

decommissioning guidance to be published at the end of September 2005. Therefore, the staff

need not respond to the issues discussed in this letter. The Committee has discussed these

issues with the staff and plans to interact with the staff again after the draft guidance is

published. The Committee believes that these early and ongoing interactions have helped the

Committee and the staff meet their respective obligations on schedule.

The Committee plans to comment on the draft guidance when it is published.

Sincerely,

IRA/

Michael T. Ryan Chairman

; . .

2 I . 411
The Honorable Nils J. Diaz -3-

* Groundwater monitoring should be a prime consideraton In the revised guidance and

should address ways to determine the requirements for subsurface characterization and

monitoring. The guidance should also address subsurface characterization, monitoring

plans, and contingency plans should groundwater contamination occur.

* The Committee recognizes that the lessons learned from decommissioning projects

provide valuable Information for designing new facilities (designing with the end in mind).

In addition to developing protocols and mechanisms for Information collection and

dissemination, the staff will need to devise a process to evaluate the accuracy and

reliability of the information that is disseminated.

The Committee has participated in the staff's information-gathering activities for the revised

decommissioning guidance to be published at the end of September 2005. Therefore, the staff

need not respond to the issues discussed in this letter. The Committee has discussed these

issues with the staff and plans to interact with the staff again after the draft guidance is

published. The Committee believes that these early and ongoing interactions have helped the

Committee and the staff meet their respective obligations on schedule.

The Committee plans to comment on the draft guidance when it is published.

Sincerely,

Michael T. Ryan

Chairman

DOCUMENT NAME: E:%FilenetWML052270028.wpd j 1 

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F-7-F -- - -- A -- N OFFICE I ACRSIAGNW I Y ACRSIAGNW I Y I AWRSIACNW I Y ACR5A I JACRSIACNW Y | ACRSIACNW I Y

NAME I RMa)or SSteele I MScott AThadanl I JLakans IJ JTLforMTRyan

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OFFIC-IA RECRDrn COPY

I
IGNOU AiCT oItVITY

W~illiam J. Hinze

C-----.-.
Status

* Evaluation of volcanism required

* Potentially important contributor

to dose

* Significant progress in developing

process scenarios and exploring

technical aspects, but differences

based on professional judgment

are recognized

36
Recent ACNW Activities

* Discussed CNWRA activities (April

2005)

* Continued document review and

discussions with NMSS

* Observed DOE's expert elicitation

of probability

* Issued letter report (December

2005)

37
Major Topics of Letter

Report

* Alternative scenario regarding

interaction of magma and

repository

* Exposure scenario describing

impact of volcanic ash on dose

* Probability of a volcanic event

38
Interaction Between Magma

and TunnelslWaste

Packages

Alternative I . ; , E ~I I 1

ir scenario

involving rapid

solidification in

tunnels ~2

39
Alternative scenario suggests:

* Waste package may not suffer

loss of integrity

* Waste released from containers

may be protected

* Magma unlikely to flow significant

distance into tunnel

* Magma unlikely to cause

secondary vents from tunnel

* Lack: of: consideration of rapid

magma solidification may lead to

unduly conservative assessment

40
Recommendation:

Analysis needs to address:

-solidification of magma in

tunnels and on waste

containers

-impact of solidification on

consequences

41
Exposure Scenario

* Progress made in updating

exposure from contaminated ash

* Health physics assumptions are

reasonable

Recommendation:

* Need to justify and document all

parameters, processes, and

assumptions

42
Probability of an Igneous

Event

Recommendation:

* Use a range of values rather than

a single value

e Alternatively, document how

single-value estimate supports a

risk-informed review and its

consequences

43
Path Forward

Committee will:

* Continue to interact on igneous

activity consequence issues

* Review and comment on igneous

activity consequence reports

when released

44
ABBREVIATIONS

ALARA

BEIR

CNWRA

DOE

HLW

ICRP

as low as reasonably

achievable

Biological Effects of Ionizing

Radiation, Committee on the

Center for Nuclear Waste

Regulatory Analyses

Department of Energy

high-level radioactive waste

International Commission on

Radiological Protection

45
ABBREVIATIONS (cont'd)

LLW

LTR

NAS

NMSS

NRC

OSHA

RES

SRP

low-level radioactive waste

License Termination Rule

National Academy of Sciences

Office of Nuclear Material

Safety and Safeguards

U.S. Nuclear Regulatory Commission

Occupational Safety and Health

Administration

Office of Nuclear Regulatory Research

standard review plan

46
a Ji

ACNW LETTERS
UNITED STATES

NUCLEAR REGULATORY COMMISSION

ADVISORY COMMIrTEE ON NUCLEAR WASTE

WASHINGTON. D.C. 205

March 25, 2005

The Honorable Nils J. Diaz

Chairman

U.S. Nuclear Regulatory Commission

Washington, D.C. 20555-0001

SUBJECT: STATUS OF HIGH-SIGNIFICANCE AGREEMENTS ASSOCIATED WITH THE

PROPOSED HIGH-LEVEL WASTE REPOSITORY AT YUCCA MOUNTAIN

Dear Chairman Diaz:

During the 157t meeting of the Advisory Committee on Nuclear Waste on February 23-25,

2005, the Committee was briefed by the NRC staff on the status of the key technical issue (KTI)

agreements associated with the proposed high-level waste repository at Yucca Mountain. A

total of 293 KTI agreements had been established to address data and analysis needs

pertaining primarily to post-closure repository performance. As a result of these meetings and

agreements, DOE committed to provide the information necessary to ensure a quality license

application (LA) and efficient LA review by the NRC.

The Committee has been proactive with regard to the issue resolution process and related

topics for several years. The Committee was briefed by DOE and NRC representatives during

its 121k, 122nd, and 12 3rd meetings, September 19-21, October 17-19, and November 27-29,

2000, respectively, on progress toward resolution of KTIs (Reference 1). During its 133'd

meeting March 19-21, 2002, the NRC staff briefed the Committee on the development of

methods for performing sensitivity analyses as part of the total system performance

assessment review (Reference 2). During its 143's meeting June 24-25,2003, the NRC staff

briefed the Committee on ranking agreements by risk significance and using risk information to

resolve Issues (Reference 3). The ACNW has also reported on other activities for riskinforming the issue resolution process (Reference 4).

At the 157'1 meeting, the staff informed the Committee that responses have been received from

DOE for all 293 agreements, and reviews related to 224 agreements have been completed.

Information concerning the remaining 69 agreements is currently under review. These reviews

are expected to be completed by April 15, 2005.

According to the staff, most of the agreements, including the agreements currently under

review, are of low or medium risk significance. The staff has identified only 41 high-significance

agreements and finished reviewing the information on these agreements. Based on these

reviews, the staff concluded DOE has fulfilled its obligation to provide information regarding 32

high-significance agreements. Resolution of most of the remaining high-significance

agreements is not expected to be problematic as resolution of these agreements is pending

DOE's release of Information to the public and some model clarifications. The staff, however,

has categorized a few high-significance agreements as "difficult issues,' (e.g., agreements on

volcanism and aircraft hazards).
E

-2-

The Committee offers the following comments and observations:

o The staff noted that though agreements were "closed" at this pre-license application

stage, any Issue or topic would be fully evaluated during the review of a license

application and that mclosing' an agreement does not preclude additional review of an

issue or topic after a license application is submitted.

o The NRC staffs agreement resolution process has been efficient and risk-informed, and

the staff has completed reviews in a timely but deliberate manner.

o The pre-licensing technical exchanges and reviews have resulted In agreements on

many technical issues. Other issues were identified as needing additional attention.

The KT1 resolution process should improve the quality of a potential DOE LA and the

efficiency of the NRC staffs licensing review.

The Committee recommends that the staff continue using its pre-licensing KTI resolution

process. In addition, because the KTI agreements are focused on the post-closure issues and

only a small number of pre-closure Issues were covered by the agreements, the Committee

believes that the staff should also now focus on pre-closure issues. The Committee will

proactively interact with the staff on the difficult issues that have been identified by the

agreement resolution process, including issues associated with volcanism and aircraft hazards.

Sincerely,

Michael T. Ryan

Chairman

References:

1. Letter dated February 8, 2001, from B. John Garrick, Chairman, Advisory Committee on

Nuclear Waste, to Richard A. Meserve, Chairman, U.S. Nuclear Regulatory

Commission, transmitting ACNW recommendations and concerns pertaining to the NRC

high-level radiative waste issue resolution process. The letter is based on briefings by

DOE and NRC representatives during the 121w, 122"0, and 123" meetings of the

Advisory Committee on Nuclear Waste September 1 9-21, October 17-19, and

November 27-29, 2000, respectively, on progress toward resolution of the KTIs.

2. Letter dated August 7, 2002, from George M. Homberger, Chairman, Advisory

Committee on Nuclear Waste, to Richard A. Meserve, Chairman, U.S. Nuclear

Regulatory Commission, transmitting ACNW recommendations pertaining to parametric

sensitivity and uncertainty analysis. The letter is based on briefings by NRC

representatives during the 133"' meeting of the Advisory Committee on Nuclear Waste,

March 19-21, 2002, on high level waste performance assessment sensitivity studies.
* S

-3-

3. Letter dated August 13, 2003, from B. John Garrick, Chairman, Advisory Committee on

Nuclear Waste, to Richard A. Meserve, Chairman, U.S. Nuclear Regulatory

Commission, transmitting ACNW comments including recommendations on the NRC

staffs issue resolution process for risk-Informing the sufficiency review of DOE's

technical basis documents for the Yucca Mountain site recommendation.

4. Letter dated September 28, 2001, from George M. Homberger, Chairman, Advisory

Committee on Nuclear Waste, to Richard A. Meserve, Chairman, U.S. Nuclear

Regulatory Commission, transmitting ACNW comments and recommendations on the

NRC staffs Issue resolution process for risk-informing the NRC sufficiency review of

DOE's technical basis documents for the Yucca Mountain site recommendation.
4.

NUC A UNITED STATES

NUCLEAR REGULATORY COMMISSION

ADVISORY COMMll|EE ON NUCLEAR WASTE

WASHINGTON, D.C. 2055-001

December 9, 2005

The Honorable Nils J. Diaz

Chairman

U.S. Nuclear Regulatory Commission

Washington, DC 20555-0001

SUBJECT: REVIEW OF THE NRC PROGRAM ON THE RISK FROM IGNEOUS ACTIVITY

AT THE PROPOSED YUCCA MOUNTAIN REPOSITORY

Dear Chairman Diaz:

The Advisory Committee on Nuclear Waste (the Committee) has met several times to discuss

the risk from igneous activity at the proposed Yucca Mountain repository. In September 2004,

the ACNW held a Working Group Meeting on this topic, and summarized its conclusions and

recommendations in a November 4, 2004 letter report The Center for Nuclear Waste

Regulatory Analyses (CNWRA) staff updated members of the Committee on NRC's current

studies on volcanism in April 2005.

Subsequent meetings, review, and analysis of recently published documents of the NRC and its

contractors, and discussions with the NRC and CNWRA staffs have resulted in the following

observations and recommendations regarding potential igneous activity at the repository.

Several of the ACNW's observations and recommendations are related to the NRC staff's use

of assumptions in their analysis that appear to be conservative rather than realistic. Excessive

conservatism can foster misperceptions of the performance of the proposed Yucca Mountain

repository and conceal attributes of processes that should receive the attention of the NRC

staff. The Committee believes continued investigation of potential scenarios will better prepare

the staff to evaluate assumptions and approaches in a potential license application. The

Committee looks forward to understanding how the staff has used risk-informed thinking

throughout the analysis of igneous activity at the proposed Yucca Mountain repository.

INTERACTION BETWEEN INTRUDING MAGMA AND REPOSITORY DRIFT AND WASTE

PACKAGES

The Committee believes that resolution of questions about the interaction between intruding

magma and the repository drift and waste packages could be better risk informed by

considering alternative Interaction scenarios and their potential influence on consequences.

Specifically, the effects on repository performance of rapid magma cooling with attendant

Increases in viscosity and solidification of magma should be considered in analyzing the

magmaldrift/waste package interactions in scenarios in which the intruding dike vents to the

surface as a volcano. The alternative scenarios and their implications include the following:
4

-2- December 9, 2005

1. Magma characteristics influence production of different materials when an igneous

intrusion intersects a repository drift. If the volatile content of magma is relatively

large, as anticipated from available evidence, volcanic ash could erupt into the drift at

the point of dike/drift intersection. Only after the entrained gases have escaped from

the magma due to eruption processes would magma enter the repository drift as a lava

flow rather than as ash. The Committee has been provided information that either ash

or lava will likely solidify near the entry point into the repository drift.

2. Key factors in the rate of solidification of the magma and self-sealing of the drift are the

delivery rate of magma, latent heat of crystallization, volatile content of the magma,

and thermal conductivity of drift walls and waste packages. As a result, the magma

would likely interact with a few waste packages near the point of entry. Rapid

solidification would likely prevent the formation of secondary (flank) vents from the

rising magma flowing into repository drifts and subsequently venting to the surface.

3. Solidification of magma entering a repository drift is an Important topic to consider

regarding the Integrity of waste packages. At.present, both the Department of Energy

(DOE) and the NRC staff assume that the contents of a relatively small number of

waste packages directly Involved in the dike intrusion are completely destroyed by

interaction with invading magma and that all the included waste is entrained in the

magma and becomes airborne after eruption. In contrast, Electric Power Research

Institute (EPRI) modeling indicates that waste packages are sufficiently robust that

invading magma will not destroy the packages (EPRI, 2004). Information presented to

the Committee suggests that quenching of magma on an intact canister could provide

a protective barrier, thereby isolating and protecting the waste from the intruding

magma. Thus, even if a few waste packages are entrained within a cone-forming

volcanic conduit, the NRC staffs altemative approach that assumes complete

destruction of the waste canisters may lead to incorrect assumptions and

parameterization in performance assessment. Undue conservatism also may lead to a

distorted view of the risks posed by the repository.

4. Waste packages will be most resistant to degradation and therefore to igneous

thermal/physical effects during the first few thousand years of repository life. This is

the time interval over which peak doses may occur from igneous activity, because

beyond that period potential doses will diminish significantly due to the decay of

shorter-lived radionuclides in the few waste packages involved In the volcanic activity

(Mohanty et al., 2004). Even if the waste is directly exposed to magma because of

package degradation after a long time period, quenching of the magma can produce a

protective rind on the waste particles.

By not including the effects of magma solidification and quenching in the extrusive event

scenario, important processes may not be adequately understood (e.g., those involved in

entrainment and eruption of waste), and both the overall consequences and the risk of the

package disruption process may be evaluated Incorrectly. DOE's choice to use a conservative

scenario to describe magma/waste package interactions does not justify overlooking insights

gained by using a more realistic scenario.

Recommendation 1. Analysis of the consequences of an igneous dike intersection

with a repository drift would be better risk informed by assessing the effects of
-3- December 9, 2005

magma solidifying upon entering a drift and quenching on the waste packages and

any waste released from them. These studies could have an impact on conclusions

regarding the number of waste packages that could be affected by a dike intrusion

and the occurrence of secondary (flank) eruptions. This in turn would impact the

amount of waste distributed in a resulting ash plume, the reasonably maximally

exposed individual (RMEI) dose, and understanding of processes important to the

total igneous activity effects.

EXPOSURE SCENARIO FROM CONTAMINATED EXTRUSIVE VOLCANIC MATERIALS

The NRC staff has updated the exposure scenario model incorporating particle size

measurements from analogous volcanic eruptions. The revised and updated performance

assessment model assumes a particle size distribution of dispersed contaminated ash with a

median aerodynamic diameter of 10 microns and a minimum aerodynamic diameter of about

0.1 microns, thus including particulate matter that is not only Inhalable but respirable.

The NRC staffs view, as presented to the Committee, is that long-term resuspension of

contaminated fluvially dispersed ash and ash deposited on the surface can contribute to an

inhalation dose to the RMEI. Consistent with this view, the NRC staff has selected parameter

values for particle size distribution, dispersion, and long-term resuspension based on direct

observation of volcanic ash at sites of recent volcanic activity. The Committee notes that these

assumptions seem reasonable. Nonetheless, the Committee believes a more fully integrated

analysis of the processes, parameters, and assumptions used in modeling this scenario would

be helpful in making the staffs approaches transparent

Recommendation 2. The parameters and assumptions presented to date regarding

the exposure scenario associated with igneous activity appear reasonable.

However, in order to be adequately prepared for the license application review, the

NRC staff should integrate all risk-significant aspects of the scenario by clearly

justifying the processes, parameters and their values, and assumptions. The

Committee believes the staff should use risk-informed approaches, including

sensitivity studies, and other techniques to study and justify its choices.

PROBABILITY OF AN IGNEOUS DIKE INTERSECTING THE REPOSITORY

The NRC staffs single-valued estimate of the probability of an igneous intrusion,1 0-7/yr over the

next 10,000 years, is at the higher end of the range of published estimates for dike intrusion on

the order of 1 04/yr to 1 07/yr, authored by the NRC staff, their contractors, and the ACNW staff

(Connor et al., 2000, Coleman et al., 2004).

Recommendation 3. The NRC staff should reevaluate the use of a single value for

probability of a volcanic intersection of the proposed Yucca Mountain repository, and

should consider a range of estimates on the order of 1 0'/yr to 1 4/yr based on studies

published by NRC and previous ACNW views. If the staff decides to use a single-point

value approach, the staff should document how this decision will support a risk-informed

review of the consequences of an igneous event In a potential license application.

Further evaluation of this range of probabilities should include consideration of new

information being assembled for, and the results of, DOE's ongoing expert elicitation on

Probabilistic Volcanic Hazard Assessment
-4- December 9, 2005

The Committee recognizes that some differences in views on volcanism between the ACNW

and the NRC staff are a matter of professional judgment The Committee appreciates the

ongoing dialogue and offers its views as complementary to the staffs views. Consideration of

these views may help the staff better risk inform their analyses of an igneous event during the

potential Yucca Mountain license application review and related decisionmaking.

Work in progress by the NRC, which Is unavailable to the Committee, may at least in part

respond to the concerns addressed in this letter. Accordingly, the Committee plans to continue

its dialogue with the NRC staff to better understand the bases of the staffs positions and to

assess issues as additional information becomes available.

Sincerely,

Michael T. Ryan

Chairman

References:

1. Coleman, N.M., B.D. Marsh, and L. Abramson. Testing Claims about Volcanic Disruption

of a Potential Geologic Repository at Yucca Mountain, Nevada, Geophys. Res. Lett.,

doi:10.102912004GL021032,2004.

2. Connor, C.B., J. Stamatakos, D. Ferrill, B. Hill, G. Ofoegbu, F. Conway, B. Sagar, and

J. Trapp. Geologic Factors Controlling Pattems of Small-volume Basaltic Volcanism:

Application to a Volcanic Hazards Assessment at Yucca Mountain, NV, J. Geophys.

Res., 105,417-432, 2000.

3. EPRI. Potential Igneous Processes Relevant to the Yucca Mountain Repository:

Extrusive Release Scenario: Analysis and Implications. EPRI Report 1008169. Electric

Power Research Institute: Palo Alto. 2004.

4. Mohanty, S., et al. System-level Performance Assessment of the Proposed Repository

at Yucca Mountain Using the Tpa Version 4.1 Code. NRC accession no. ML041350316.

2004.