ML20147F774
| ML20147F774 | |
| Person / Time | |
|---|---|
| Issue date: | 12/13/1978 |
| From: | Gossick L NRC OFFICE OF THE EXECUTIVE DIRECTOR FOR OPERATIONS (EDO) |
| To: | |
| References | |
| RTR-WASH-1400 SECY-78-637A, NUDOCS 7812260009 | |
| Download: ML20147F774 (20) | |
Text
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UNITED STATES
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December 13, 1978 SECY-78-637A
- h. FORMATION REPORT FOR:
The Comissioners FROM:
Lee V. Gossick Executive Director for Operations
SUBJECT:
SUPPLEMENTS TO SECY-78-637:
PROPOSED NRC STATEMENT ON RISK ASSESSMENT AND THE REACTOR SAFETY STUDr REPORT (WASH-1400) IN LIGHT OF THE RISK ASSESSMENT REVIEW GROUP REPORT DISCUSSION:
Enclosed are the IE and MPA comments to assist in your review of the above subject. Also enclosed are additional NMSS comments.
i i
A Lee V. Gossick 7
Executive Director for Operations
Enclosures:
as stated 1
SECY NOTE: This paper is currently scheduled for a Commicsion briefing on~
Thursday, December 14, 1978.
DISTRIBUTION Commissioners Commission Staff Offices Exec Dir for Operations ACRS Secretariat 7818260 Coq
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O UNIT ED $TATES
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NUCLEAR REGULATORY COMMISSION 3Mg 4
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WAGHIGTON, D. C. 20555
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s December 13, 1978 MEMORANDUM FOR: Lee V. Gossick Executive Director for Operations FROM:
John G. Davis, Acting Director Office of Inspection and Enforcement
SUBJECT:
NRC STATEMENT ON RISK ASSESSMENT AllD THE REACTOR SAFETY STUDY This memorandum expresses limited IE concurrence on the draft "NRC Statement on Risk Assessment and the Reactor Safety Study" which was forwarded to you by a December 8, 1978, memorandum signed by Harold R. Denton.
We believe that the IE use of the RSS -- which has been limited --
has been consistent with that recommended by the Risk Assessment Review Group. Also, it is our intent that any planned future use by IE will be consistent with the recommendations or guidance provided within NRC.
Because of IE's lack of involvement in those areas of specific comment by the Review Group, IE is not in a position either to agree or disagree with any specific Review Group comment nor the reaction to any comment by the NRC Staff.
IE is not aware of the extent of reliance by other NRC O'ffices on the RSS because of lack of involvement by IE in this reliance.
Hence, IE's position is that of concurring insofar as IE's use of the RSS.
J hn G. Davis Acting Director Office of Inspection and Enforcement
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4 UNITED STATES
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NUCLEAR REGULATORY COMMISslON
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W ASHINGTON, D. C. 20555 Ih'v[/
December 12, 1978 MEMORANDUM FOR: Lee V. Gossick Executive Director for Operations THRV:
Nonnan M. Haller, Director
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- 3 7F Office of Management and Program Analysis FROM:
Lee R. Abramson, David Rubinstein and Roger H. Moore Applied Statistics Branch Division of Technical Support Office of Management and Program Analysis
SUBJECT:
DRAFT STATEMENT "NRC STATEMENT ON RISK ASSESSMENT AND THE REACTOR SAFETY STUDY," AN ENCLOSURE WITH A MEM0-RANDUM FROM HAROLD R. DENTON, NRR, TO LEE V. GOSSICK, EDO, "NRC STATEMENT ON RISK ASSESSMENT AND THE REACTOR SAFETY STUDY (WASH-1400) IN LIGHT OF THE RISK ASSESSMENT REVIEW GROUP REPORT," DECEMBER 8, 1978 We believe that the draft statement is not responsive to a number of points raised by the Risk Assessment Review Group (RARG). Both the tone of the draft and certain specific phrasings give rise to this belief. We set them forth here for your consideration, with full recognition of the problems generated by the " range of views on the RSS" mentior.ed in the third paragraph of Mr. Denton's memorandum.
Hand-annotated copies of Mr. Denton's memorandum and the draft statement are attached with each of the following comments indicated in the right' margin. The comments are divided into two groups:
those dealing with the general tone of the draft and identified by (T), and those dealing with specific phrasing and identified by (S).
Please call for any additional information that may be required to sharpen these points.
COMMENTS (T-1)
The important and necessary distinctions among such concepts as " Risk Assessment," " WASH-1400 Methodology," and " Fault-Tree / Event-Tree Methooology" are not established and main-tained. Moreover, general methodology is not distinguished from specific implementation.
For example, the RARG endorses Risk Assessment, while firmly rejecting its implementation I believe the policy statement should have two major themes: (1) specific risk estimates'in the RSS should not be used uncritically; and (2) proper use of risk assessment methodology offers an important means of guiding the nuclear regulatory process.
Theme (1) involves three issues -- Have RSS risk estimates been used un-critically? If so, what corrective actions must NRC now take (e.g. concerning safety)?
And, what procedures are needed to prevent future uncritical use? Th a need to develop plans which specify the role of risk assessment in b2) gggs re y
process and the technical steps required for proper use (e.g. improving the data base and statistics).
-),
Lee V. Gossick.
by the souare-root bounding model. This clearly throws into dispute the draf t statement's declaration that "The Review Group endorsed the methodology of the Reactor' Safety Study..."
,To illustrate in another way: Given that the RSS's assign-ment was to perform a risk assessment of nuclear power reactors, what portions of WASH-1400 methodoloay.are acceptable to the NRC (and the RARG) other than fault-tree / event-tree methods?
(T-2)
"A number of technical deficiencies" is used in the draft (p.4) with the effect of downplaying such RARG statements as
"... invention and use of wrona [our emphasis] statistical methods..." and "... unable to define whether the overall probability of a core melt given in WASH-1400 is high or low, but we are certain that the error bands are understated."
(This last item is taken to mean that neither direction nor magnitude of bias nor precision of estimate can be trusted.)
Since the RARG leaves the pedigree of most -- if not all --
of the numerical values reported in WASH-1400 in doubt, any NRC statement on these matt.ers must come to grips with this problem.
(T-3)
No guidance is offered in the draft -- nor is any promised as forthcoming -- for use of WASH-1400 outside of NRC.
The instruction at the bottom of p.6 may be intended to cover this; but, if so, it should be given " action item" st'atus in the list of 5 items on pages 7 and 8.
Indeed, any future in-NRC use must l
have this guidance as well.
(T-4)
The " inscrutability of WASH-1400" issue is not addressed.
In the absence of a concordance or a " road map," continued debate /
discussion over what the RSS did or didn't do can be expected.
More particularly, associating a " range of uncertainty" with each "RSS risk estimate" will add another layer of problems.
To estimate something is one thing; to estimate a relevant measure of uncertainty is quite another.
l (T-5)
The draft considerably softens the RARG conclusions concerning the Executive Summary.
(S-1)
Page 1 -- 14th line -- The tenn " decision analysis" is introduced and does not appear to be used for any particular purpose in the remainder of the draft. We suggest that it be dropped.
Lee V. Gossick,
(S-2)
Page 4 -- 5th line -
"... limi ted use... b' NRC s taff..."
y seems to leave open all sorts of questions. Perhaps a reference to the results of the recent all-NRC review exercise is in order.
(S-3)
Page. 4 -- 5th thru 14th lines -- In light of RARG findings, it can be concluded from the paragraph that the technical staff was " familiarized" with many of the wrong things. The very last point ascribing to the RSS " considerable advances in risk assessment technology" should perhaps be moderated.
Probabili ty, statistics, fault and event trees have been around for a long time. There is no doubt that laying out the reactor accident sequences was a formidable task and praised by most reviewers.
But' laudable application of a method is not -the same as considerable advancement of the method.
(S-4)
Page 5 -- 4th thru 10th lines -- Does " application of the RSS methods" mean that all of them -- even the ones found wrong or misapplied by the RARG -- are included in the " valuable supplement" phrase? This whole paragraph, especially with
" encouraged" and " emphasis" and " rigorous" as key words, leaves the Comission and the Staff open for charges of not providing sufficient internal control to locate and isolate the RSS methods that are now found wanting.
(L5)
Page 6 -- 1st and 2nd lines -- Admission of instances of misuse should be accompanied by reference, perhaps, of the specific findings of the recent review of use of WASH-1400 in-house. Having opened the issue, the draft statement cannot leave its resolution to a passing reference such as
... it is now generally agreed that the range of uncertainty associated with RSS risk estimates is far greater than that presented in the RSS."
(S-6)
Page 6 -- 13th and 14th lines -- From what sources can one expect to obtain a " range of estimates" that pertain to a particular~ risk estimate's characterization? There are many ways to go about answering this question, but understanding of options goes along with the listing of the results.
(S-7)
Page 5 -- 18th line -- To declare "n_o, [our emphasis] undue reliance" o
seems too strong, given the results of the recent survey.
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Lee V. Gossick.
(S-8)
Page 7 -- 1st line -- The only way to " minimize the potential" is to never use the RSS. Surely that is not the intention of the Comission or Staff. The important issue is: How is
, misuse of WASH-1400 to be controlled?
(S-9)
Page 7 - 10th thru 14th lines -- It remains unclear just how future requests for individual copies of the Executive Summary will be treated.
(S-10) Page 7 - 18th thru 22nd lines -- Management of this "second round" requirement could be quite complex. Among the worries:
What happens if the second round review and comments leaves issues unresolved? Who determines which reports have potential to affect policy?
(S-11 ) Page 8 -- 4th line -- The problem of WASH-1400's inscrutability permeated the RARG report.
Is that problem included in "the many technical issues and deficiencies" list? Or is another sort of initiative expected, one aimed at clarity and careful exposition?
(S-12) Page 8 -- 9th thru 13th lines -- This is good advice for environmental statements -- as long as RSS is referred to in them. But, if WASH-1400 is deficient in estimating limitations and ranges of its own estimates,, then it is not clear to us how an environmental statemer,t can reflect this shortfall or correct for it..Furthermore, singling out environmental statements for this treatment falls short of the NRC taking into cognizance these difficult issues in other areas of activity.
(S-13) Page 8 -- 15th thru 17th lines - "... care will have to be taken... " is a very weak statement and applies to any methodology.
In particular, this statement could have been written before the RARG report and does not reflect any of the findings and recommendations made in the RARG report about certain applications of the techniques carried out in the RSS.
a% O, Lee R. Abramson 2(yk k b 'tE) k*h David Rubinstein bc9c" b
\\ Roger H. Moore Attachments:
As stated
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Annotated by PRM:12/9/78
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MEMORANDUM FOR: Lee V. Gossick Executive Director for Operations FROM:
Harold R. Denton, Director Office of Nuclear Reactor Regulation
SUBJECT:
NRC STATEMENT ON RISK ASSESSMENT AND THE REACTOR SAFETY STUDY REPORT (WASH-1400) IN LIGHT OF THE RISK ASSESSMENT REVIEW GROUP REPORT Enclosed is a revised draft of the statement on Commission views and actions in response to the Risk Assessment Review Group's report. NRR has had discussions with SD, NMSS, IE, RES, as well as with the ED0 staff and OPE.
This version was prepared with the intent that the NRC should respond OPE /MPA in a positive and constructive way to the recommendations of the Risk drafter Assessment Review Group.
We have been careful to avoid overreaction had same g
to isolated statements in the Risk Assessment Review Group report and good have tried to present a clear, balanced view.
The proposed statement goals!
is concurred in by NRR, SD, RES, and NMSS.
There are two points which are not explicitly dealt with in the state-ment.
First, you snould realize that there has been a range of views on the RSS.among the Of fices.
Some staff members have continued to be very critical of the RSS while others have found the benefits of th.e RSS to greatly outweigh its technical flaws. These views have no doubt puts dow shaped the various uses (or lack of use) of the RSS.
More importantly, many RAE they have shaped the various views on the significance of the Review points Group report to the licensing' process. The proposed statement deals with the issues raised in the Review Group report but does not attempt tc characterize the rcnge of individual views on the RSS and its use.
A draft report on the staff's survey of the use of the RSS is being transmitted separately and will aid in your review of the proposed sta tement.
A simple chronology of the history of the RSS is also en-closed to assist in that review.
Second, the previous draft called for a plan for systematically guiding future applications of the RSS methodology.
While several groups have called for such a plan, it was concluded tNit this need
Lee V. Gossick DEC 0 6 FJ78
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not be part of a statement on the RSS.
The revised' draft encourages" including the use of the RSS methodoloay and notes that additional guidelines
" square will be developed but does not call for a specific action plan.
root"?
While it was concluded that the above items should not be included in the 11RC statement, we will be prepared to discuss them at the up-coming Commission meeting.
Harold R. Denton, Director Office of Nuclear Reactor Regulation
Enclosures:
1.
Chronology on the RSS 2.
Draft Statement on Risk Assessment /
Lewi s Comm'.ttee Report l
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DEC06'EIS Enclosure.
CHR0:10 LOGY
'l.
December 4,1.970 Letter, Commissionar Larson to Senator Gravel, noted that AEC plans to hav.e a study made and report prepared to cover area covered by WASH-740.
2.
March 26, 1971 SECY R-199 p'rovided possible approaches on study of nuclear risks and benefits.
3.
June 2, 1971 Regulatory Information Meeting No. 482, proposed study of nuclear risks and benefits requested by-Commission.
Relationship of proposed study to Price-Anderson Act emphasized.
4.
April 5, 1972 SECY R-432 Policy Paper en MIT proposal for study of risks due to acciden s in nuclear power reactors (intended to be separate from but coordi-nated with a companion study in RDT of all other risks / benefits of electrical energy process).
5.
August 4, 1972 Reactor Safety Study (RSS) initiated.
6.
August 20, 1974 Draft RSS (WASH-1400) distributec for comments.
7.
Aucust 23, 1974 AEC Interim General Statement of Policy released,
- 2 39FR30964 (cf. SECY-R-75-62) 8.
September 1974 AEC Regulatory staff review group formed to review draft RSS.
9.
December 3, 1974 Initial. report of Regulatory staff review of draft RSS (cf. SECY-R-75-133).
10.
January 19, 1975 NRC formed, RSS study group assigned to RES.
Responsibility for RSS effort transferred from AEC to NRC.
11.
March 4, 1S75 Commission briefing on WASH-1400 draft and comments (cf. SECY 75-51) 12.
April 25, 1975 Report to the American Physical Society by the Study Group en Light Wa er Reacter Safety.
12.
May 30, 1975 Detailed Regulatory staff comments on craf t RSS.
y
14.
October 30, 1975 Final RSS (WASH-1400) issued (Press release "o.75-259 included Chairman Anders' statement on RSS).
15.
November 15, 1975 Preliminary Review of WASH-1400 (Final) by HRC staff / consultant review group.
16.
June 11,.1976 Udall Subcomittee oversight hearing on continuing criticism of RSS.
17..
February 7, 1977 Udall Subcommittee observations on the RSS.
18.
March 2, 1977l Memo Gossick to Comissioner Kennedy regarding staff pesition on application of the RSS to the licensing process.
19.
March 14, 1977 Udall requests formation of a review group to prepare new Executive Summary for RSS.
20.
April 4, 1977 Chairman Rowden commits to form review group with different charter.
21.
May 15, 1977 Memo Chilk to Gossick on Co:r: mission's desires for use.of risk assessment methods in licensing practices.
22.
July 1, 1977 Risk Assessment Review Group (Lewis Comittee) formed.
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23.
September 7, 1978 Risk Assessment Review Group Report (NUREG/CR-0400) published.
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DEC0519T6 NRC STATEID!T OR RISK ASSESSIO!T AND THE REACTOR SAFETY STUDY Protection of the public health and safety is a paramount objective of the Nuclear Regulatory Commission in regulating the design, construction and operation of' nuclear power plants.
The operation of nuclear power plants can never be completely risk-free.
Tne safety objective of the NRC has always been to assure that the risk from normal operation and ac-cidents is maintained at an acceptably low level and to assure that tne likelihood of accidents more severe than those considered in the design is extremely small.
This safety objective has not been set forth in numerical terms in,the Commission's regulations, largely because it has not been possible to make quantitative estimates of the risks to the public from nuclear power plants with sufficient precision to be us,eful as licensing criteria.
The Reactor Safety Study (RSS) was an attempt to use the emerging disci-plines of risk analysis and decision analysis to develop quantitative (S-1) estimates of the risks of nuclear reactor accidents.
At the time the stuoy was initiated, it was recognized that the study might not De suc-ces sf ul in reaching this gpal and that further research and development might ce necessary before quantitative estimates of risk could be de-veloped with sufficient precision to be useful for licensing purooses.
.u.v 2
In August 1974, the report on the Reactor Safety Study was issusd ir, craf t form for public comment.
In commenting on that draf t, the Atomic Energy Commission stated that the study, when completed, would be the sucject of a thorough evaluation "...with respect to both the basic question whe'ther the risks portrayed by the study are acceptable from the standpoint of the Commission's statutory responsibility to protect the health and safety of the public, and the' related question wnether any changes in the Commission's safety or environmental reguiations are warranted."1/ In thi s statement, the AEC also cet forth an interim position that "...the contents of the craft study are not an appropriate basis for licensing decisions."
l'ar.y individuals and groups reviewed the draf t RSS anc provided comments.
In addition to the request for public carments, the AEC reouested members of the regulatory staff not previously assigned to the study to perform a review of the draft study.
The comments of the AEC regulatory staff and others pointed out oeficiencies in the RSS.
In October 1975, the final report of the Reactor Safety Study was issued (WASH-1400/NUREG 74-014 ).
Although the final report included responses to comments received on the draft report, critics of the final report maintained that the stuoy still contained serious flaws and pointed out tha many adverse comments on the draft were not suitably taken into a;.
c o ur. t.
In particular, comments were mede that the Executive Summary of 1i 2'
39 FR 30964, " Interim General Statement of Policy," August 23, 1974
v.,
3 the Reactor Safety 5tudy was presented in a manne.r which created a mis-leading impression of the certainty and comprehensiveness of the study's
' con:1 usions.
These concerns were considered.in connection with a Congressional review of the strdy.
Following publication of the results of this review and an excnance of correspondence between the URC and Congressman horris K. Udall, the NRC formed an independent group to further consioer this matter.
The Commission established the following charter for the Review Group:
"The Review Group will provide advice and information to the Commission regardine the final report of the Reactor Safety Study, WASH-1400, and the peer comments on the Study, advice and recommendations on developments in the field of risk assessment methodology a'nd on future courses of action which shoul d be' taken to improve this methoool ogy and its application.
This advice' ahd information will as-sist the Commission in establishing p61 icy regarding the use of risk assessment in the regulatory process, in im-proving the base for the use of such asse'ssments.
it will also clarify the achievements and' limitations of the Reactor.Sa fety Study."
The Review Group presented its findings and recommendations to the Commis-sior, en September 7,1978 and its ' report was issued as an liRC cocument NUR EG/CR-0400.
In general, the Commission agrees with the findings and re:ommendations of the Review Group.
The Review Group endorsed the methodolocy of the Reactor Safety Stuoy ano (T-1) creater use Of risk assessment in the regulatory process.
However, they 2150 agreed with the critical views of others that the final report on the
'975 i
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4 Reactor Safety Study suffers from a number of technical deficiencies and (T-2)
,that the final report did not respond adequately to the peer comments on the draft.
In view of the Review Group's comments, the Commission has re-cently requested a review of past Commis,sion and staff uses of the RSS.
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The review has shown that there has been limited use of such assessments (S-2) by the liRC staff in the past. There is a lack of explicit requirements or guidelines for the use of probabilistic assessments, and particularly prooabilistic risk assessments similar to those of the Reactor Safety Stuoy.
However, as analytical techniques for carrying out such assess-ments have become more accepted ano as more operating experience, with (S-3) its associated data, has become availacie, there has been increased use of probabilistic assessments. The Reactor Safety Study contributed much to familiarizing the technical staff with the use of these assessments and made considerable advances in risk assessment methodoloov.
Probabilistic techniques were in use by the staff'before publication of the RSS as support for some of the judgments reached in the reactor li-Their use has ranged from the simple semi-quantitative censing process.
arguments in support of a judgment that plant operation can continue for a limited time pending implementation of a neeoed modification, to quanti-tative fault tree / event tree analyses to help determine the need for and j
nature of additional licensing recuirements (e.g., as in consioeration of protection against enticipatec transients without sc r am).
The primary rui.'At of the staff's application of the RSS in the licensing orocess has t
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Deer. the imposition of additional requiremenEss for. protection agqinst
-tr.ose accidents identified in the RSS as major contributors to risk, rather than reductions in existing requirements.
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l Sin:e the issuance of the fin'al RSS report the Commission has also viewed-app ication of _the RSS methods as a valuable suppl ement to present li-(S-4).
censir.; practice, and has encouraged the staff to use those methods in this fashicn in making recommendations on important safety issues before the Ccmri s si o n.
As an example, emphasis has been given to the use of risk as-sessment in providing a means~ for more rigorous characterization of cur-i ren value-impact analyses.
r The Commission believes that uses of the RSS such as described above are censistent with the statement of the Review Group that the fault tree / event
~l tree cethodology used in the RSS "should oe among the principal means used F
tc teal with generic safety issues, to formulate new regulatory require-men s, to assess and revalidate existing regulatory requirementsc and to evalua te new designs."
The Commission concludes that the staff should con-tinue to utilize fault tree and event tree analyses to aid in reviews of various safety i ssues.
The, Commission also will continue to support im-prove ents and extensions of risk assessment theory, methods, data devel-and statistical analyses to promote their proper and effective use o ment oy tne NRC staff, kcsever, tne record of past uses of the RSS by the staf f ar.d Commissior, is ret entirely f avorable.
The Review Grovo noted tha: there have beer
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l instances when the RSS was misused as a vehicle to judge the acceptability (S-5) of reactor risks. The Commission's review confirms this finding.
Some Commission and staff statements have cited resul ts freni the RSS, particu-(T-5) j
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larly those in the Executive Summary, without identifying the uncertainties associated with the results as presented in the RSS itself.
Moreover, as reflected in the report of the Review Group, it is now generally agreed that the range of uncertainty associated with the RSS risk' estimates is (T-4) far greater than that presented in the RSS.
The Commission Delieves that while the Reactor Safety Study concludes that reactor accident risks are very low, the rance of uncertainty in these (T-4) es 1 mates does not permit an unqualified conclusion tnat tney are clearly lower than other natural or man-caused risks.
The existing assessments of
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risk are sufficiently uncertain that it is better to characterize the RSS (S-6) results in tenns of a rance of estimates ano make any comparisons of risk based on that range.
Such use would provide an added perspective on ac-cident risks not otherwi se available.
In sum, the results of the Commission's review of past uses of the RSS indicate that there has been limited application of and,n_o undue reliance (S-7) on the RSS in licensing aecisions.
There have beer number of statements oy the Commission and the staff whose language was not properly'oualified.
To some extent such statements may have created a misleadine impression of the cecprehensiveness and certainty of the Reactor Safety Study resuits.
The Ccmmission has instructed the staff to cevelop whatever guidelines (T-3) f
DEC0555
.7 may.be determined necessary to minimize the potential for uncritical use (s-8)
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of the RSS in the future.
In addition to the general observations discussed above, the-Review Group made a n' umber of specific findings and recommendations dealing with var-fous parts of the Reactor Safety Study and the use of risk assessment methodol ogy.
The Commission generally agrees with these findinos and recommendations and will take them into account in-its future actions.
In addition, the Commission has determined that the following specific actions are appropriate:
(1)
Copies of the Risk Assessment Review Group Report (NUREG/CR-0400)
(T-5) and of Lthis statement w'll be sent to all known recipients of the i
RSS and the Executive Summary.
Copies of the RSS, including the (s-9)
Executive Summary bound with the-main report, will be accompanied by :opies of the Review Group's report and this statement.
(2) The Commission will review the staff's current practices and pro-cedures for peer review of significant staff reports to identify any needed improvements.
(3 )
Major NRC reports which may have the potential to affect policy, such as the RSS, and which receive extensive criticism or recuire (S-10) substantive chances when issued for comments, should be recircu-lated for a second round review and comment before being issued
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as a final recort.
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DEC0Fi378 i
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(4 ) The Commission is giving support to ongoing work aimed at up-grading the use of risk assessment methodology'.in the regulatory process.
Follow-on studies to the RSS will address the many technical issues and deficiencies raised by the Review Group, (s_11)
Reports on these studies idll indicate the full range of un '
certainties associated with the studies and acknowledge exitting criticism and these uncertainties and criticisms will aise be dis-cussed in any Executive Summaries.
(5) The staff's environnental statements on LWR applications contain a discussion of accident risks and include reference'to the RSS.
All new or revised LWR environnental statements will,.in their
)
discussion of the RSS, also discuss the limitations or range of uncertainty associated with the RSS resul ts.
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I The RSS should be seen as 'one step, already accomplisheo, in the contin-
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uing development of risk assessment methodology.
While the RSS has de-veloped risk assessment methods of considerable utility to the reguia-(S-13)
{
tory process, care will have to be taken in any use of these cuantita _
l tive risk technioues.
To keep the Congress and public informed, the Ccamission will publish the results of the ef forts described above, in-ciuding the programs to pranote and insure more effective and careful use of the RSS methodol ogy.
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%,g UNITED STATES NUCLEAR REGULATORY COMMISSION p-wAsmuuroN,0. C. 20555 December 12, 1978 MEMORANDUM FOR: Harold R. Denton, Director Office of Nuclear Reactor Regulation FROM:
William J. Dircks, Acting Director Office of Nuclear Material Safety and Safeguards
SUBJECT:
NRC STATEMENT ON RISK ASSESSMENT AND THE REACTOR SAFETY STUDY REPORT (WASH-1400) IN LIGHT OF THE RISK ASSESSMENT REVIEW GROUP REPORT We appreciate the opportunity to review the draft statement on Comission views and actions in response to the Risk Assessment Review Group's report. We find that this matter is mainly related to reactor licensing and has relatively little relevance to NMSS activities, with the possible exception of item 3 noted below. Therefore, our participation in this effort has been somewhat limited and the following coments are offered as clarifications:
1.
On page 1, the statement that "The operation of nuclear plants can never be completely risk-free." is true; however, we believe that the sa ce statement applies to all power plants and is not peculiar to y
nuclear units and that the statement should be re-phrased accordingly.
2.
The discussion on page'2 spans the period'from Au. gust 1974 to October
}
- 3M75mnd covers actions by the AEC and its successor, the NRC, without
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' differeiiitiating between the two organizations.
It is believed that a simple change could be made to indicate that the AEC issued the draft report in August 1974, and the final report in October 1975 was issued by HRC.
3.
The NMSS staff agrees with the five Commission actions with the exception that we believe that item 3 should be modified to address draft reports which receive extensive. criticism and also " require substantive changes" at the comment stage.
J a.
y 2-flarold R. Denton 4.
From an editorial standpoint, the statement is presently eight pages in length without any break.
For ease and style it might be helpful to provide the following or similar subheadings for portions of the report. The first three pages could be called " Background" or
" Introduction"; pages 4, 5 and 6 "Present Status" or "Present Situation"; and pages 7 and 8 " Commission Actions."
This memorandum confirms telephone comments provided by Homer Lowenberg of NMSS to Ed Case on December 8.
NHSS has reviewed the document from the standpoint of its impact on NMSS programs.
Its relevance to our progra'ms is minor. With the exception of the issue identified in item 3, we have no objection to the document.
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Willia J. Dircks, Acting Director Office of Nuclear Material Safety and Safeguards cc:
E. G. Case D. F. Bunch e
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