ML20196J193
| ML20196J193 | |
| Person / Time | |
|---|---|
| Issue date: | 05/19/1997 |
| From: | Pomeroy P NRC ADVISORY COMMITTEE ON NUCLEAR WASTE (ACNW) |
| To: | Shirley Ann Jackson, The Chairman NRC COMMISSION (OCM) |
| References | |
| NACNUCLE-S-0088, NACNUCLE-S-88, NUDOCS 9708040043 | |
| Download: ML20196J193 (4) | |
Text
,
- -. - - ~,
y
% ua j
UNITED STATES ACNWS-0088 NUCLEAR REGULATORY COMMISSION o
3
,j ADVISOR.Y COMMITTEE ON NUCLEAR WASTE
[g '/
f~
WASHINGTON. D.C. 20556 j.
- . +
May 19, 1997 4
?
J d.
The Honorable Shirley Ann Jackson Chairman
- U.S. Nuclear Regulatory Commission
[
Washington, D.C. 20555-0001
!j,
Dear Chairman Jackson:
j
SUBJECT:
SUMMARY
REPORT-91ST MEETING OF THE ADVISORY COMMITTEE ON 1
NUCLEAR WASTE, APRIL 22-24,1997, AND OTHER RELATED ACNW ACTIVI-l TIES During its 91st meeting on April 22-24,1997, held at Two White Flint North,11545 Rockville Pike, Rockville, Maryland, the Advisory Committee on Nuclear Waste (ACNW) discussed several key issues and completed the report that follows:
REPORT a.
}'
' Report to The Honorable Edward McGaffigan, Jr., Commissioner, NRC, from Dr. Paul W.
Pomeroy, Chairman, ACNW,,* Final Rule on Radiological Criteria for License Termination," dated l
April 24,1997.
HIGHLIGHTS OF KEY ISSUES CONSIDERED BY THE COMMITTEE 1.
The Status of laneous Activity Related to the Proposed Yucca Mountain Repository The ACNW held a working group session on the subject of igneous activity with representa-tives from the Department of Energy (DOE), the Nuclear Regulatory Commission (NRC), and the State of Nevada. This session was held to review the status of knowledge about the probability, consequence, and risk of an igneous event to the proposed high-level waste (HLW) repository. DOE has estimated that the annual probability of a volcanic event ranges from 10E-7 to 10E-10, based on expert judgment. On the basis of such a low probability, DOE has discontinued its site characterization program. The NRC determined the annual probability to be between 10E-7 and 10E-8 per year (10E-3 to 10E-4 in 10,000 years), and considers 10E-7 to be an appropriate conservative value for DOE to use in its performance j
assessment (PA). On the basis of preliminary analyses, the NRC has calculated a y c g consequence of 500 mrem /yr, and a risk (probability x consequence) of 0.5 mrem /yr. The 37 NRC staff continues to conduct field and modeling studies to test conceptual models and constrain uncertainty.
l h The Committee asked whether additional field work is likely to yield new information that could increase NRC's probability estimate of 10E-7. The staff indicated that additional field work is needed because the discovery of new volcanic cones could potentially change the 1-7 4th k @v - t, ~P o
I'J003t Xo to" ' ' ~ DESIGNATED ORIGINAI Ul.# Nl,#lgeI i
9709040043 970519 9 b tif1ed By-
.h i
j PDR ADVCM NACNUCLE 8-0088 PDR3 h
('
The Honorable Shirley Ann Jackson 2
conceptual model. If the cones are not present, this information would increase NRC's confidence in its probability estimate.
f 1
Conclusions / Action items:
i in the future, following briefings on this topic by DOE and industry representatives, the Committee will send a letter report to the Commission, with the Committee's recommenda-i tions.
2.
Nevada Perspective on the Difference Between DOE's Viability Assessment and the Site Suitability Determination for the Proposed Yucca Mountain Repositorv Mr. Steve Frishman, Agency for Nuclear Projects, State of Nevada, presented the State's views on the following topics:
DOE's proposed revisions to 10 CFR Part 960 Nevada's perspectives on the difference between DOE's viability assessment and a site suitability determination Nevada's perspectives on the value of NRC's subsystem performance requirements l
NRC's issue-resolution process l
Mr. Frishman noted that his intent in discussing these topics with the Committee was to l
inform ACNW, in its role as advisor to the Commission, of the potential difficulties that could l
arise if each of these topics was not properly considered.
Ms. Linda Lehman, President, Technical & Regulatory Evaluations Group, Inc., discussed the value of State oversight to the DOE Yucca Mountain project. She discussed the State of Nevada's unsaturated zone model, particularly its value in calculating groundwater travel time and flux rates. Ms. Lehman noted that DOE is only now using values for groundwater flux as high as 10 mm/yr, suggested by the State a half decade ago. Also discussed were relevant State dilution calculations.
Conclusions / Action items:
The Committee asked to be kept informed of State progress in the areas noted above, i
suggesting a follow-up in the next 6 months of any progress with DOE and NRC insofar as l
integration of accepted data and models.
I 3.
Reaularly Scheduled information Exchance Between the ACNW and the Director, Division of Waste Manaoement. Office of Nuclear Material Safety and Safeauards l
John T. Greeves, Director, Division of Waste Management (DWM), Office of Nuclear Material i
Safety and Safeguards (NMSS), discussed current issues of mutual interest to the
]
Committee and the DWM. These discussions included the following:
Commission activities conceming the Decommissioning Rule i
i r
i e
0
The Honorable Shirley Ann Jackson 3
r establishment of a task force on NRC regulation of DOE facilities status of Congrerdr,s,; jegislation on waste disposal and management e
issues in developing the Intemational Convention on Waste Management
=
issues related to low-level waste and decommissioning status of the proposed revisions to the DOE HLW siting guidelines status of the Yucca Mountain site characterization program Conclusions / Actions:
This portion of the meeting was part of a regularly scheduled information exchange between the Committee and the Director.
1 4.
Defense in Depth Dr. Charles Fairhurst, University of Minnesota, presented his views on the subsystem requirements in 10 CFR Part 60 and the defense-in-depth philosophy. Dr. Fairhurst served as a member of the National Academy of Sciences (NAS) Committee on Rethinking High-Level Waste, as we!! as the NAS Technical Bases for Yucca Mountain Standards Committee. This briefing enabled the Committee to hear altemative viewpoints regarding the subsystem requirements and to begin formulating advice to the Commission on this topic.
Dr. Fairhurst recommended that prescriptive requirements should be eliminated in favor of a more flexible approach, allowing for revision of the design and the regulations as obstacles are encountered. He encouraged adopting a dose-based, rather than a release-based, standard, because the same release at two different sites poses different consequences.
l Conclusion / Actions:
In the future, following discussions with representatives of DOE and industry, the Committee j
will prepare a letter report for the Commission, with the Committee's recommendations on the use of defense-in-depth principles.
i 5.
ProDosed Schedule for the 92nd ACNW Meetino The Committee agreed to consider the following issues at the 92nd ACNW meeting, May 20-f 22,1997:
Meetina Wrth the Nuclear Raoulatory Commission -The Committee will prepare for i
a meeting and meet with the Commission to discuss items of mutual interest. Topics i
i will include the ACNW priority list and earlier Committee reports on the reference biosphere and critical group, flow and transport models for Yucca Mountain, coupled processes in NRC's HLW prelicensing program, igneous activity at Yucca Mountain, and risk-informed, performance-based regulations. The Committee is scheduled to meet with the Commission on May 20,1997, at 2:00 p.m.
i l
I
The Honorable Shirley Ann Jackson 4
Generic Methodolooy for Decommissionina Performance Assessment - The Committee will review the use of PA in the decommissioning of various facilities.
Meetino With the Director. Division of Waste Manaoement. NMSS - The Committee will discuss current events with the Director, DWM, NMSS. Topics might include the j
status of work at the Yucca Mountain site, and HLW standards and regulations.
j i
Meetino Wrth Representatives of the DOE and NRC-The Committee will meet with representatives of the Department of Energy and the NRC staff to discuss DOE's Project Integrated Safety Assessment (PISA) exper:ence with the use of expert elicitation in the HWL repository program, and comments on the defense-in-depth philosophy.
Spent Fuel Drv Storace Facilities-The Committee will review a draft version of the NRC staff's Standard Review Plan for a Spent Fuel, Dry Storage Facility.
Central interim Storace Facility-The Committee will review DOE's non-site-specific Topical Safety Analysis Report for a Central Interim Storage Facility.
Preparation of ACNW Reports -The Committee will discuss potential reports, including igneous activity related to the proposed Yucca Mountain repository, and other topics discussed at the meeting, as necessary.
4 OTHER RELATED ACTIVITIES OF THE COMMITTEE The Committee discussed potential candidates for nomination to ACNW membership. A slate of candidates was submitted to the Commission.
Sincerely, 4
)M
'. /
Paul W. Pomero Chairman v
1 4