ML20035E006
| ML20035E006 | |
| Person / Time | |
|---|---|
| Issue date: | 02/07/1992 |
| From: | Ward D Advisory Committee on Reactor Safeguards |
| To: | Advisory Committee on Reactor Safeguards |
| Shared Package | |
| ML20035D940 | List: |
| References | |
| ACRS-2817A, NUDOCS 9304140175 | |
| Download: ML20035E006 (7) | |
Text
.
o UNITED STATES E
~,%
NUCLEAR REGULATORY COMMISSION
{
ADVISORY COMMITTEE ON REACTOR SAFEGUARDS o
W ASHINGTON. D. C. 20555
/
February 7, 1992 MEMORANDUM To:
FILE FROM:
David A. Ward, Chairman
SUBJECT:
KEY TECHNICAL ISSUES TO BE CONSIDERED BY ACRS IN COMING MONTHS This memorandum documents plans for ACRS study of certain key technical issues as discussed during the 381st meeting, January 9-11, 1992.
Preliminary discussion of these issues was carried out in an ad hoc subcommittee meeting in Baltimore, Maryland, on November 22-24, 1991.
Two groups of issues are described below.
The first six are related to ALWR design certification.
For these, ACRS efforts need to be carried out on a schedule compatible with the overall NRC certification program.
Issues 7 through 12 have more general application to future NRC programs.
In each case the issue is described by a series of questions and the ACRS plan for its action is then briefly summarized.
While this list describes issues the Committee has singled out for early attention, it is not intended to be in any way a comprehensive list of the Committee's current or future activities.
ISSUES RELATED TO ALWR DESIGN CERTIFICATION 1.
What are the safety and regulatory implications of integratedt, computer-based control and protection systems?
Can these systems introduce unique kinds of plant failure.s which are outside the existing experience base for NPPs, but which might become important given vide use of computer-based systems?
How can NRC regulate the design and operation of such systems without unnecessarily limiting innovation?
Is there professional staff within the NRC adequate for dealing with these issues?
What are the man-machine implications of these systems?
A somewhat broader question is whether there is a need for
" General Operating Criteria," paralleling the General Design Criteria of 10 CFR Part 50, Appendix A?
t 9304140175 920603 o[
MEMORANDUM TO FILE 2
ACRS action:
A planned series of subcommittee meetings extending through 1992 is already under way which will involve NRC staff, industry, and subject-matter experts.
Consider-ation will be given to cosponsoring an international workshop on the subject somewhere along the way.
After necessary assimilation of information, ACRS will synthesize important lessons and make recommendations to the Commission.
Our goal is to complete this in late 1992.
2.
If deterministic criteria are to continue to be used for licensing, should NRC move beyond the " single failure criteri-on" as the~ keystone of safety design, to other means of assuring the safety performances of a plant systems and components?
Should "N+2" be required for certain systems?
Should regulations provide reliability requirements, rather than deterministic ones?
Should there be a limit on the reliability level that can be credited to and expected from any given system, perhaps no greater than a value that can be demonstrated by ordinary, transparent means, e.g.,
99 percent?
Should reliability requirements be systematically allocated among syster.s and components?
If so, should these be derived from a top-level overall goal -- related to the Safety Goal?
Should the distinction between safety and nonsafety systems be maintained?
ACRS action:
The Committee agreed to actively pursue these questions; a specific plan of action remains to be developed.
The goal vould be to make recommendations to the Commission in time to influence the review of the " passive" LWR and later
- designs, i.e.,
by mid-to late 1992.
3.
Should separation or independence requirements for redundant safety trains be upgraded to explicitly account for more subtle environmental threats than are considered in existing regulatory practice?
Examples are adverse effects of the spread of smoke, heat (as through HVAC systems), steam, hot l
gases, water, and spurious or real fire extinguishing efforts.
Are existing standards and requirements adequate to ensure that there can be no undesirable interdependence among supposedly independent systems or trains because of common (or inadequately separated) service and support systems, especial-ly in the case of nonsafety systems?
i b
MEMORANDUM TO FILE 3
Should unwanted actions by affected components, as well as failures to act, be considered?
ACRS action:
ACRS will, over the next several months, hold subcommittee meetings with
- staff, vendors, and EPRI to determine present requirements and practices relative to these issues, using EPRI, ABWR, and APWR work as examples.
Our goal is to make recommendations for bolstering regulations or regulatory practices to the Commission following a period of discussion and debate, in mid-1992.
Should NRC require certain design features to deal explicitly 4.
with control of risk during shutdown and low power operations?
ACRS_ action:
The Committee agreed to follow the NRC program closely.
We will look to see if consideration is being given to expanding the program to address the need for possible fundamental redesign of certain plant systems (e.g., handling heavy loads over an open reactor core) to reduce the opportun-ities for events that lead to shutdown risks.
5.
Is the Safety Goal a good enough definition of how safe future plants should be?
If the answer is yes, why are we trying to improve them?
If the answer is no, what is an appropriate goal?
ACRS action:
After discussion the Committee reached no conclusions, nor did it develop plans for further review.
\\
6.
Should a revised set of DBAs or criteria be required of new plant designs, e.g.,
taking more explicit account of severe accidents?
ACRS action:
The ACRS letter of May 17, 1991 on containment criteria proposed that containment designs for the passive LWR generation of plants should be based on severe accident criteria.
The Committee agreed that this general approach would be useful for other systems and more advanced designs, 1
but no specific plan of action was developed.
MORE GENERAL ISSUES I
7.
Important new safety issues might arise in the future, in new or old plants.
What might they be?
ACRS action:
After discussion the Committee reached no i
conclusions nor planned any action beyond plans for a briefing on the status of advanced reactor developments around the world, and continued briefings on operating experience.
l l
h MEMORANDUM TO FILE 4
8.
What are the most important issues involving the safety in operating the current generation of plants?
ACRS action:
After discussion the Committee developed no new agenda for focusing on or pursuing this issue, beyond continu-ing to follow operating experience.
9.
Are there important issues with regard to license renewal that have not been identified or are being neglected?
ACRS action:
The Committee concluded that the NRC program is proceeding well and that beyond following this program, no particular ACRS action beyond our normal activities is warranted.
The Plant License Renewal Subcommittee will take the lead on this action.
10.
Should the Safety Goal Policy be broadened to incorporate an explicit guideline or goal related to land or resource contamination, separate from the health effects goals?
ACRS action:
The Committee will discuss this at a meeting in early 1992.
2 11.
Can and should semiarbitrary containment challenges be specified for PIUS, CANDU, PRISM, and MHTGR to serve as a basis for containment designs? Should ACRS develop proposals?
ACRS action:
The Committee agreed to consider a program along L
the lines of that it carried out for the LWR containment criteria effort.
A schedule remains to be developed.
l 12.
Does commitment to the concept of physical defense-in-depth mean that MHTGR and PRISM must have traditional containments?
ACRS action:
The Committee will discuss this at a future f
meeting.
i l
kb i
To: DAVE WARD Message 0: 19147 e..-
From: BILL KERR Submitted: Wed 4/8/92-20:04
Subject:
long term issues Status: Public Received: No Group: ACRS Dave:In a file labeled LTISSUE.WK are some comments stimula red by Selin's suggestions when he met with us at the April Meeting.
To: DAVE WARD Message #: 19161 From: BILL KERR Submitted: Thu 4/9/92 - 11:48
Subject:
lonf term issues Status: Public Received: No Group: ACRS Dave:
My original transm,DDCission of the file of LONG TERM ISSUES was incomplete. To see the complete document look in a file labeled LTISSUE1.WK.
File name: LTISSUELWK TOPICS FORIDNG TERM CONSIDERATION During his meeting with the Committee on April 2,1992 Qiairman Selin suggested that we consider developing, in consultation with the Commission, a list of topics of sufficient importance that we give continuing attention to them. From time to time we would discuss these topics with the Commission, and, presumably, we would occasionally transmit a written report giving collegial views or recommendations resulting from our deliberations.
Although we did not formally consider this request any further during the April meeting. (I presume we will later) I think it is a good idea, and suggest we get on with the task ofidentifying topics and of planning for their consideration by the Committee.
I suggest the following topics that might become part of such a list:
- 1. Implementation of the Safety Goals -I think we all agree that this is an important topic even though at this point we may not agree on what the term means. Our first task is probably to try to reach a consensus on that. Insofar as I understand the position discussed in Hal's memo prepared for consideration by the ad hoc committee I think I agree with it, i.e. the Safety Goals provide a yardstick by which we can measure the performance of the population of nuclear plants.
If we conclude, by whatever measure, and I think the measure willinclude consideration of the results of a significant sample of PRAs, but will not be confined to that, that the i
population of plants is not meeting the Goals, then we probably should adjust the regulatory system (including but not necessarily limited to the regulations) in an effort to achieve an acceptable level of conformance. If we conclude that the population is meeting the goals there are still choices to be made. One choice is to do nothing more. However,for whatever p/
reason, it may be considered appropriate to enhance the safety performance of all plants, a class of plants, or even of one ATTACHMENT F plant. (Note that there is already precedent to set risk levels lower than that required for safety. Appendix I of
10CFR50 was formulated to appease those who calculated the additional number of" deaths" that might occur if the permissible public exposure to the radiation from radioactive materials released by normally operating power plants was that prescribed by 10CFR20.) Ifit is decided that risk reduction beyond the Safety Goal target is desirable, then cost benefit is a possible way to measure how far to go. Some fonn of PRA, either plant specific or generic will then presumably be used to decide on an appropriate fix. But a determination of whether the Safety Goals are being met for the population of operating plants should be kept separate from the question of an appropriate backfit analysis.
- 2. The SALP Process - We have expressed concem about the process in the past, and the Commission has instructed the staff to make some changes. We should continue to examine this process, not only the way it is su pposed to function, but the way in which it actually works. In my own earlier consideration of the process I thought the insistence of the people responsible for the evaluations and for the interaction with licensees were being too zealous in their insistence that continuing improvements should occur in the ratings. In trying to understand why they would exhibit this zeal I have now concluded that it is not because they are all little tyrants who are acting this way because they want to demonstrate their powers, but rather that many of the people in the regions, including the regional directors, are convinced that the existing regulations are not effective in insuring an appropriate level of safety. I know they proclaim that a "3" SALP rating does not mean that the plant is unsafe, and that they want continuing improvement only because they do not believe it is possible to maintain a fixed level of safety ("If the organization is not improving it will be degrading"), but I'm convinced that this is the patty line that makes it possible, in their view, to try to achieve the improvements
[
that they consider necessary without doing something as drastic J
as shutting a plant down. And maybe they are correct. Perhaps Grh we need to look at existing regulations that have to do with plant operations. Many of the regulations were developed i
primarily to deal with plant design and construction. Possibly i
the existing regulations are not adequate to deal with merations, but if they art.neMh1TIhey should be upgra The process for-protnulgating regulations which provides for i
public and industry input is likely to produce a better result than the SALP process which has little input from sources outside the staff.
- 3. Systematic Review of Existing Regulations - From time to time we have suggested this. It deserves more attention.
After all we did have a review of older plants to ensure that they met the intent if not the letter of improvements required
)
in later plants. And of course the existing regulations have i
evolved over time as need has arisen to deal with a newly identified problem. I'm unaware, however, of any systematic review of the whole body of the regulatory process. It is I
clear that there has not been enough attention given to questions such as:
a)Is the single failure criterion an adequate specification j
of the reliability that should be required of certain high y
reliability systems?
i b) How should non. safety systems be regulated? In PRA space
we know that they contribute significant risk. Do existing regulations recognize this?
c) How should severe accidents be treated? Existing regulations all but ignore them. This issue is of panicular i
importance to new plants.
The resolution of the above is likely to be resource intensive, i
and is likely to take a significant amount of time. I believe each deserves the attention of both the Commission and the ACRS.
i wk 8-IV-92 t
9 e
2 1
I I
i l
B T
3 1
3/
t
/p =en,,[:.
UNITED STATES
-[ j(,"c.
i NUCLEAR REGULATORY COMMISSION 3
E ADVISORY COMMITTEE ON NUCLEAR WASTE k
~'#I f
WASHINGTON. O C. 20555 s, ~ j May 1, 1992 The Honorable Ivan Selin Chairman U.S. Nuclear Regulatory Commission Washington, D.C.
20555
Dear Chairman Selin:
SUBJECT:
PROGRAM PLAN FOR THE ADVISORY COMMITTEE ON NUCLEAR WASTE Since December 1989, the Advisory Committee on Nuclear Waste (ACNW) has provided at four-month intervals a program plan of anticipated Committee activities.
This letter covers May through August 1
1992.
We view these letters as a convenient avenue for us to share information on our proposed activities.
We invite you to provide guidance on issues on which the Commission desires that we focus our efforts.
In preparing this program plan, we have considered the list of technical issues of particular interest to the Commission, requests of individual Commissioners, the list of items proposed' by the EDO's office for ACRS and ACNW consideration, the NRC's Five-Year
- Plan, and items of particular interest and/or concern to the Committee members.
The priority for each issue proposed is based on information provided by representatives of NMSS, NRR, RES, and the EDO's office, as well as our own interpretation of the subject in relation to our activities as a Committee and our input into the regulatory process.
This program plan is based on the current best estimates of work output by the DOE, EPA, NRC staff, and their consultants and contractorn, as well as our own views on how to deal with these issues effectively.
In addition to the full Committee meetings
- noted, we will hold working group maatings as necessary to facilitate full Committee review and action.
There may be some revisions to this plan depending on the progress of NRC staff, applicant, and/or contractor studies and reviews, as well as other schedular problems beyond our control.
i Since the August meeting has been deferred, the next program plan will be submitted in September.
M M s + ; o M l-ATTACHMENT G
~
s f
The Honorable Ivan Selin 2
May 1, 1992 Full Committee meeting dates for this period are tentatively scheduled as follows-43rd meeting May 28-29, 1992 44th meeting June 23-25, 1992 (Site Visit / Meeting, Richland, Washington) 45th meeting July 30-31, 1992 46th meeting Deferred to September 24-25, 1992 The Committee anticipates that it will consider the topics listed below during this four-month period.
May 28-29. 1992 - 43rd ACNW Meetina e
The Committee will address a
supplemental request from Chairman Selin made on April 24, 1992, on a systems analysis approach to reviewing the overall high-level waste program.
(High Priority) e The Committee will review and comment on the design-basis-accident rulemaking for a
high-level waste repository (Controlled-Use Area / Design Basis Accident Limit).
(High Priority)
The Committee will review and comment on proposed changes to e
10 CFR Part 72 concerning emergency planning for independent spent fuel storage installations and a monitored retrievable storage facility.
(High Priority)
The Committee will hear a report on relevant topics discussed l
e during the 24th Annual Meeting of the Conference of State Radiation Control Program Directors, Inc.
(Medium Priority) e The Committee will be briefed on the adoption by EPA of a revised Hazard Ranking System for use in assessing the risk associated with the release or potential release into the environment of hazardous chemicals and/or radioactive mate-l rials.
(Medium Priority)
June 23-25. 1992 (Site Visits /Meetinos) i The Committee will visit facilities at the Hanford reservation and meet near Richland, Washington.
Current plans include:
e Tuesday. June 23. 1992 (Site Visits)
U.S.
Ecology waste disposal facility l
Briefing / demonstration of geoscience models used to predict radionuclide transport 33
The Honorable Ivan Selin 3
May 1, 1992 e
Wednesday, June 24, 1992 (Site Visit)
Visit LLW grouting facilities Visit site of LLW in-situ vitrification experiments Visit and discussion of N-Reactor decommissioning program Visit one of the original graphite reactors e
Thursday, June 25, 1992 (A.M.
- Site Visit)
Visit with LLW modeling and Performance Assessment groups including current program and international perspectives e
Thursday, June 25, 1992 (P.M.) 44th ACNW Meetina (Public Meet-ing)
Topics include:
The Committee will address the request from Chairman Selin made on April 24, 1992, for a supplemental report regarding the systems analysis approach to reviewing the overall high-level waste program.
(High Priority)
The Committee will hear a report from the ACNW Working Group Chairman on a recent meeting in which the NRC s.taff presented the results of their review of DOE's Early Site i
Suitability Evaluation.
It is anticipated that ACNW comments on these topics will be prepared.
(High Priority) l 1
Status of remedial actions at the Hanford site.
(High Priority)
Briefing and discussion of HLW vitrification program (Medium Priority) i July 30-31, 1992 - 45th ACNW Meetinc The Committee will address a supplemental request from Chair-e man Selin made on April 24, 1992, on a systems analysis approach to reviewing the overall high-level waste program.
(High Priority)
The Committee will review and comment on a proposed technical e
position on the repository design for thermal loads.
(Medium Priority)
The Committee will discuss with a representative of the State e
of Connecticut experiences related to the selection of a site 3
The Honorable Ivan Selin 4
May 1, 1992 for a low-level radioactive waste disposal facility.
(Medium Priority)
Au._qu st 13-14, 1992 - 46th ACNW Meetina Deferred until September 24-25, 1992.
e Other Tooics:
(Will be considered as documents and time become available consistent with priorities noted)
The Committee will be briefed by the HLW staff on its position e
on penetration of the Calico Hills tuff and their review of DOE's Calico Hills / Risk-Benefit Analysis. (High Priority)
The Committee will be briefed by the DOE on the Yucca Mountain e
Project Office data management system.
(Medium Priority)
The Committee will be briefed on the NRC staff's review of the e
DOE reports on the Exploratory Studies Facility Alternatives Study and site suitability analyses.
(High Priority)
WORKING GROUP MEETINGS ACNW Workino Group on NRC Staff Comments on the DOE's Early Site Suitability Evaluation (ESSE) for the, yucca Mountain Hich-Level Recositorv, June 17, 1992.
The Working Group will be briefed by the NRC staff regarding issues and concerns resulting fron'the NRC staff's review of DOE's ESSE and its associuted conclusions.
ACNW Workinc Groun on Phase 2 of the HLW Iterative Performance Assessment (IPA), September 23, 1992 (Tentative) Bethesda, Md. The Working Group will discuss the progress of Phase 2 of the HLW Iterative Performance Assessment effort by NRC.
The Group will also be briefed by DOE representatives regarding the status of the DOE's Total Syste.m Performance Assessment.
ACNW Workino Groun on Inadvertent Human Intrusion Related to the Presence of Natural Resources at a Hich-Level Recository Site, October 21, 1992, Bethesda, Md.
The Working Group will discuss methodologies for the assessment of the potential for natural resources at the proposed high-level vaste repository site at Yucca Mountain.
The relationship between such resources and the potential for human intrusion will be emphasized.
The Working Group will also consider a DOE study plan on this topic.
The Imoact of Lona-Rance Climate Chance in the Area of the Southern Basin and Rance, November 18, 1992 (Tentative), Bethesda, Md. - The Working Group will discuss the historical evidence and the potential for climate changes in the Southern Basin and Range and 35
h r
i The Honorable Ivan Selin 5
May 1, 1992 l
I the impact of climate changes on the performance of the proposed i
high-level radioactive vaste repository at Yucca Mountain.
i L
This list represents our best estimate of the topics to be l
considered through August 1992.
If you or the other Commissioners have additional items to suggest or proposed changes in priorities, please let us know.
l Sincerely, Dade W. Moeller Chairman t
cc:
Commissioner Rogers Commissioner Curtiss l
Commissioner Remick i
i Commissioner de Planque Samuel J. Chilk, SECY James M. Taylor, EDO Robert M.
Bernero, NMSS i
I
=
l l
1 l
4 36
.