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ACNW MEETING WITH

THE COMMISSION

B. John Garrick

July 21, 2004
a,

Today's Agenda

* Risk Insights Activities

- B.J. Garrick

* Working Group Meetings

- Biosphere Dose Calculations

*M.T. Ryan

- Geosphere Transport

*G.M. Hornberger

2
Today's Agenda

(Cont'd)

* Other Committee Activities.

-NRC/CNWRA research

*R.F. Weiner

-West Valley Site

*M.T. Ryan

* Closing Comments:

-B.J. Garrick

3
I -

ACNW RISK INSIGHTS

ACTiVITI ES

B. John Garrick
Focus

* NMSS Task Force on PRA

* Yucca Mountain Risk Baseline

Report

5
Observations

* Radiation dose is an indicator

of health and safety risk and

is favored as a basis for

developing risk-informed

guidelines

* Risk-informed regulation

concepts are being tested on

real issues and facilities

6
Observations

(Cont'd)

* Population collective dose is

limited as an indicator of risk

for nuclear materials

scenarios with small, longm

term releases or small

exposures to many people

7
Recommendations

* Risk guidelines should be

linked to radiation dose rather

than health effects

* Staff should move away from

collective dose as a measure

of risk

8
REVI EW OF YUUCCA

MOUNTAIN HLW

RISK BASELINE REPORT

B. John Garrick
Risk Baseline

Report Review

* 2004 Risk Baseline Report

-details how risk

considerations are factored

into KTI reviews

-important element of issue

resolution process

10
Risk Baseline Review

(Cont'd)

* Evaluated relative to waste

isolation capabilities of

repository system

* Staff considered three

categories of significance to

waste isolation

-high, medium, low

11
Recommendations

* Use risk insights to focus on

most important KTI

agreements

-translate risk- insights into

specific guidance on

prioritizing issue resolution

12
WORKING GROUP

MEETINGS

Michael T. Ryan
Purposes

* Recent focus on Yucca

Mountain technical issues

* Learn about staff and DOE

activities and plans

* Identify technical issues that

may warrant further study

* Offer a vehicle for public

participation

14
Areas Of Review

* Previous working groups

-Transportation

-Performance confirmation

-TSPA

* Recent working groups

-Biosphere dose assessments

-Geosphere transport

15
Biosphere Dose

Assessment WG

* Goal ... focused on metabolic

models and environmental

pathway analysis

* Conducted in February 2004

* Panel of six invited experts

16
Biosphere WG

(Cont'd)

* Discussions Focused On...

-technical bases necessary

for biosphere dose

assessments

-role of risk insights in the

development of technical

bases

17
a)

Biosphere WG:

Observations

* Predicted doses are small,

near background levels

* No high-risk performance

issues for the base case

* Several conservatisms are

present

* Realism of calculations could

be improved

18
Observations (Cont'd)

* Igneous eruption could

potentially have significant

effect on risk estimates

* Research should continue to

focus on inhalation intake

parameters and aerosol

resuspension

19
GEOSPHERE TRANSPORT

WORKING GROUP

George M. Hornberger
Purposes

* Goal ... To review expected

behavior of radionuclides in

aquifers at Yucca Mountain

* Conducted in June 2004

* Panel of four invited experts

21
Geosphere Transport:

Observations

* Most of predicted dose from a

few Radionuclides

-Np-237, 14129, and Tc-99

* Flow paths, travel times,

matrix diffusion, and

retardation are important

considerations

22
Observations (Cont'd)

* Highly retarded radionuclides

(i.e., Pu, Am) never arrive at

compliance boundary

* Calculated travel times for

mobile radionuclides in

aquifer -1 00s to 1 000s of

years

23
Observations (Cont'd.)

* Work by NRC, DOE, and

others indicates that

natural system is an

effective barrier

24
Observations (Cont'd.)

*Additional information

could reduce uncertainty

-groundwater discharge

-matrix diffusion

-sorption coefficients

-water chemistry

25
Observations (Cont'd.)

* Even modest Np retardation in

alluvium delays arrival at

compliance point past 10,000

years

26
CENTER FOR NUCLEAR

WASTE REGU LATO RY

ANALYSES

PROGRAMSINIRC

RESEARCH PROGRAMS

Ruth F.l Weiner
Current Activities

* Review of Selected CNWRA

Programs

-March 4, 2004, letter report

-Review of RES Radionuclide

Transport Research

-May 5, 2004, letter report

28
CNWRA Programs

* ACNW Review Focused on:

-igneous activity

-spent fuel/water interactions

-corrosion studies

-post-closure drift stability

-pre-closure Safety Analysis

(PCSA) Tool

29
CNWRA Programs (Cont'd)

* ACNW Provided Comments

on:

-inhalation models for

exposure to volcanic ash

-use of uranium dioxide in

dissolution studies (in progress)

30
CNWRA Programs (Cont'd)

-drift stability

-improVements and

transparency of the Center's

PCSA tool

31
PCSA Tool

* Review of the PCSA Tool

Showed:

-adequate modeling flexibility

-appropriate modeling of

accident scenarios

-transparency

-traceability

32
Conclusions

* Evaluated CNWRA work is

addressing issues of

importance to NRC

* Evaluated CNWRA work

continues to be of high quality

33
WEST VALLEY SITE

Michael T. Ryan
Complex Site

* Land Surrounding WVDP

-unrestricted use

* Parts of WVDP

- restricted use

* Burial Sites

-long-term license

* Vitrified HLW

-awaiting geologic repository

35
DOE Performance

Assessment Approaches

* To be Used to Demonstrate

Compliance with LTR

-deterministic, bounding, and

probabilistic analyses are

planned

36
NRC StaffIs Independent

Performance Assessment

* Probabilistic in Nature

* Uses Realistic Assumptions

* ACNW Strongly Encourages

Staffs Approach

37
ACNW Next Steps

* Meet with DOE and NYSERDA

as EIS and PA Plans Mature

* Periodic Meetings with

Involved stakeholders

* Report on Progress to the

Commission

38
CLOSING COMMENTS

B. John Garrick
ACNW Action Plan

* Undertake reviews of

Commission-approved topics

* Action Plan to be updated to

reflect approved topics

40
Action Plan (Cont'd)

* Working with NMSS

Management on process

improvements

* Work with staff to identify

predecisional topics for

Commission approval

41
Future Activities

* Working Group Meetings

-goal of one per quarter

-future subject areas...

* Igneous activity (September 2004)

* Health physics/radiation biology

(December 2004)

42
Future Activities (cont'd)

* West Valley performance

assessment (CY 2005)

* Support Commission

adjudicatory technical staff

43
ABBREVIATIONS

ACNW Advisory Committee on

Nuclear Waste

Am, Np, Pu Americium, Neptunium,

Plutonium

CNWRA Center for Nuclear Waste

Regulatory Analyses

DOE U.S. Department of Energy

EIS Environmental Impact

Statement

44
ABBREVIATIONS (Cont'd)

HLW High-level nuclear waste

KTI Key technical issue

LTR License Termination Rule

NMSS Office of Nuclear Material

Safety and Safeguards

NYSERDA N.Y. State Energy

Research Development

Authority

45
ABBREVIATIONS (Cont'd)

PA

PCSA

PRA

RES

TSPA

Performance assessment

Pre-closure safety analysis

Probabilistic risk

assessment

NRC Office of Nuclear

Regulatory Research

Total system performance

assessment

46
ABBREVIATIONS (Cont'd)

WG Working group

WVDP West Valley

Demonstration Project

47