ML17223A264

FOIA/PA-2017-0575 - Resp 1 - Final. Agency Records Subject to the Request Are Enclosed

ML17223A264
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Issue date:	08/11/2017
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FOIA/PA-2017-0575
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NRC FORM 464 Part I U.S. NUCLEAR REGULATORY COMMISSION FOIA RESPONSE NUMBER (03-2017)'

RESPONSE TO FREEDOM OF I 2011-0575 II 1 INFORMATION ACT (FOIA} REQUEST RESPONSE TYPE D INTERIM I V' I FINAL REQUESTER: DATE:

\Edward Burns 11 8 { I/ (JO I 7 I DESCRIPTION OF REQUESTED RECORDS:

SECY-89-328, Use of Probabilistic Risk Assessment in Resolving Safety Issues, dated October 24, 1989 (ML12251A683)

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D We have withheld certain information pursuant to the FOIA exemptions described, and for the reasons stated, in Part II.

Because this is an interim response to your request, you may not appeal at this time. We will notify you of your right to D appeal any of the responses we have issued in response to your request when we issue our final determination.

You may appeal this final determination within 90 calendar days of the date of this response by sending a letter or e-mail to the FOIA Officer, at U.S. Nuclear Regulatory Commission, Washington, D.C. 20555-0001, or FOIA.Resource@nrc.gov. Please be D sure to include on your letter or email that it is a "FOIA Appeal." You have the right to seek dispute resolution services from the NRC's Public Liaison, or the Office of Government Information Services (OGIS). Contact information for OGIS is available at https://ogis.archives.gov/about-ogis/contact-information.htm PART l.C COMMENTS ( Use attached Comments continuation page if required)

Please note:

The attached following responsive record is being released in its entirety:

ML12251A683 Sianature - Fr=>dom of Information A ~- r ex Desicmee NRG Form 464 Part 1103-2017). Page 2 of 2

October 24. 1989 SECY-89-328 POLJCY ISSUE

{Information)

The Commissioners James M. Taylor Acting Executive Director for Operations Sub,iect: USE OF PROBABILISTIC RISK ASSESSMENT IN RESOLVING SAFETY ISSUES

Purpose:

To inform the Commission of staff practices in the use of probabi1istic risk assessment {PRA) in resolving safety issues. (Staff Requirements Memorandum M8904138, dated April 20, 1989.)

Summary: During the staff's briefing of the Commission on* April 13, 1989 on plans for implementing the Safety Goal Policy, the Chairman suggested that the staff may wish to make additional recommendations to the Commission on this subject. After reviewing existing guidance on this matter, the staff has concluded that no additional recommendations on the use of PRA in resolving safety issues, beyond that incorporated in SECY 89-102, "Implementation of Safety Goal Policy," are needed at this time.

This paper identifies guidance that has been given to the staff to date. It also describes the use of PRA results to estimate the potential benefits of proposed resolutions.

Background:

The use of PRA by the staff as a factor in making safety decisions, subject to qualifications, was authorized by a statement issued by the Commission dated January 18, 1979 and entitled "NRC Statement on Risk Assessment and the Reactor Safety Study Report {WASH-1400) in light of the Risk Assessment Review Group Report." It was attached to a memorandum from the Secretary of the Commission to the Executive Director for Operations, also dated January 18, 1979, providing instructions from the Com.mission to the Staff {Enclosure). Among other things the instructions inc1uded the following:

Contact:

R. W. Houston, RES X23900

The Commissioners 2 "Quantitative risk assessment techniques may be used to estimate the relative importance of potential nuclear power plant accident sequences or other features where sufficient similarity exists so that comparisons are not invalidated by lack of an adequate data base.---"

Subsequently the staff began its development and application of guidelines (NUREG/BR-0058) for the conduct of regulatory analyses. A companion document prepared for staff use, a Handbook for Value Impact Assessment (NUREG/CR-3568), issued in December 1983, provides supplementary guidance that recognizes that PRA would usually be involved in regulatory analyses for potential new regulatory requirements arising from safety issues.

In January 1983, the Commission published in NUREG-0885, Issue 2, "US NRC Policy and Planning Guidance" the following, under the heading "Risk Assessment":

Policy A. Probabilistic risk assessment is a useful tool for weighing risks against one another and for estimating achieved safety levels. Quantitative risk assessment techniques will be used

• judiciously by the Staff and the boards as directed by the Commission to estimate the relative importance of potential nuclear power plant accident sequences.

Planning Guidance

1. Special attention should be given to using probabilistic assessment techniques in the evaluation period for safety goals, as directed by the Commission, and in other regulatory applications especially amenable to risk assessment, e.g., in dealing with generic safety issues, formulating new regulatory requirements, assessing and revalidating or eliminating existing regulatory requirements, evaluating new designs, and setting reactor safety research and inspection priorities.

2. Consideration will be given to the uncertainties associated with existing probabilistic risk assessment techniques whenever used in regulatory decisions.

The Commissioners 3 The Commission approved charter of the Committee to Review Generic Requirements (CRGR} recognizes the use of "probabilistic risk assessment where data for its proper use are adequate."

In the development and publication of the Commission's Safety Goal Policy Statement dated August 4, 1986, a relationship between PRA and quantitative objectives was clearly recognized, and the Commission authorized the staff to use the two Quantitative Health Objectives to gauge achievement of the safety goals.

The Second Draft NUREG-1150, "Severe Accident Risks: An Assessment for Five U.S. Nuclear Power Plants" was published for peer review in June 1989. This document updated and incorporated important advances in PRA technology developed over the last five years. It includes the latest research results on severe accidents, improved core damage and containment performance analysis, and potential effects of external events. The prospective uses of NUREG-1150 as a resource document are described in the Foreword and in Chapter 13. The use of PRA in the process of resolution of safety issues discussed below is consistent with that description.

Discussion: In virtually all cases in which the staff has employed PRA to assist in the resolution of safety issues it has involved a process that compares results of a PRA treatment on one or more particular plants on a before and after basis. The

before basis" represents a plant for which the safety issue is known or believed to exist. The "after basis" reflects a hypothetical modification that might resolve the issue. The difference so calculated represents an estimate of the net value or benefit of a proposed resolution. The recently completed NUREG-1150 analyses provide models which can be used to evaluate new issues in a similar fashion in the future.

A gauge of a prospective increase in protection of the public used by the staff is the estimate of the net reduction in population dose {person-rem). This requires the use of PRA treatments to estimate source terms (level 2) and to carry out consequence calculations (Level 3). Core damage frequencies (Level 1) enter the calculations to estimate the annualized consequences which are then summed over the expected {remaining) life of the plant. In regulatory analyses carried out pursuant to the backfit rule, 10 CFR 50.109, the staff generally employs the cost-benefit guideline ratio ($1000/person-rem) directly,

The Commissioners 4 and does not have a separate and distinct rule-of-thumb benchmark for the benefit expressed as a reduction in person-rem. In practice, however, it is found that cost-benefit ratios that might justify regulatory action tend to show population dose reductions averaging greater than a few hundred person-rem per year over the expected balance of plant life. Thus, a population dose reduction in this range or greater is judged by the staff to represent "a substantial increase in the overall protection of the public health and safety---." [10 CFR 50.109 (a) (3)]

The resolution of some safety issues can reduce the probability of core damage or core melt. In these cases the staff typically uses a Level 1 PRA to estimate a net reduction in core damage frequency (CDF). In itself this is a useful gauge of potential safety benefit and is an indirect measure of increased protection of the public. This focus on core damage reflects the importance of prevention of core damage, the fact that Level 1 PRA information is generally more robust than Level 2 and 3, and is consistent with the accident prevention philosophy embodied in several major rulemaking initiatives (e.g., ATWS, ECCS, Station Blackout, and Appendix R). There are two safety issues, however, for which the staff developed specific quantitative resolution objectives that focus on core damage frequency. These are discussed below.

The Station Blackout Issue: USI A-44 In the regulatory analysis for the resolution of the station blackout issue (NUREG-1109, June 1988), the following statement appears under the heading of Objectives:

"The general objective of the requirements to resolve USI A-44 is to reduce the risk of severe accidents associated with station blackout by making station blackout a relatively small contributor to the average freguency of core damage for the total population of plants." (Underline added for emphasis.)

Thus, the intended comparative test of significance focused on the relative residual contribution to an integrated total CDF, rather than the magnitude of expected reduction. The staff recognized that this would literally require a PRA on every plant in order to measure "the average frequency of core damage for the total population of plants." On the basis of existing PRAs, however, the staff estimated that such an average CDF would likely be of the order of 1 in

The Commissioners 5 10,000 per reactor year. Informally th~ staff then set as its goal a contribution to CDF from station blackout events of 10% of that estimated average, i.e., 1 in 100,000 per reactor year. This approach had its origin in the parti-tioning process and sequence level probabilistic targets derived for the process of prioritizing generic safety issues (NUREG-0933). The regulatory analysis for the resolution of the station b1ackout issue showed that this goal should be closely achieved by the station blackout rule..

The Decay Heat Removal Issue: USI A-45 The second safety issue for which the staff set a similar goal dealt with Shutdown Decay Heat Removal Requirements.

As described in SECY-88-260, September 13, 1988, in this case the goal set was that the overall residual contribution to core damage due to failure of the decay heat removal function should be less than 1 in 100,000 per reactor year.

It was also noted that this was approximately the same as was expected to be achieved by the resolution of the station blackout issue, as indicated above.

Relation to Safety Goal Policy The staff has recommended in SECY-89-102, March 30, 1989, Implementation of Safety Goal Policy, the use of a quantitative objective for overall core damage frequency as an integrated benchmark against which prospective changes in regulatory requirements could be gauged. The objective recommended was 1 in 10,000 per reactor year, integrated over all core damage sequences. This is part of the hierarchy of quantitative objectives in the recommended implementation process.

The staff also recommended the use of subsidiary objectives that represent a partitioning of the overall core damage frequency objective. (Section C.3 of SECY 89-102). This partitioning represents an allocation of the overall COF to individual classes of events. The approach used in the resolution process for the two issues described above is consistent with these staff recommendations on the use of quantitative objectives in the implementation of Safety Goai Policy.

The Conunissioners 6

==

Conclusion:==

At the present time the staff is not directly using an.overall CDF target of 1 in 10,000 per reactor year in the generic issue resolution process but would do so with Commission approval of the recommendations in SECY 89-102.

The staff believes that its recommendations on CDF objectives should not be isolated from the broader plan for implementing the Safety Goal Policy.

Director

Enclosure:

As stated DISTRIBUTION:

Commissioners OGC OIG LSS GPA REGIONAL OFrICES EDO ACRS ACNW ASLBP Jl_SLAP SECY

,.. .-. I IC......, ._. 4 r,. 1 __.

w 'CL::.:...n. REGl!:Lf... TO RY co:,'S,lS.S!Ot~ -

- W.:.SHll*GTON, D. C. 2CS:S:S (

January 18. 1979 O Fi=1 ::.!:: OF .-r! E

!:::::: ?. IT1-t:;y P.iliD?.ANDUM FOR: Lee V. Gossick Executjve Director for fROX:

• Samuel J.* Chi1k

_.Secretary of t.he

SUBJECT:

STAFF ACT10NS REGARDING REVIEW GROUP REPORT

.!\t"t;ached is a p::>iicy statment issued by the Cciiriiission on Jc.nuary *1s, i979. In ~dclition, the Coli!liission h::.s provided the fo11ohing instructions for the staff.

i. Send copies of the Risk Assessment Review Group Report (HUREG/CR-

• 0400) and of the January 18, 1979 Corrmission policy statement to a11 .

l::narm domestic and international rei::ipients of the RSS. In the future*~ .

copies of* the RSS Executive Surrrnary and the comp1 ete RSS wil 1 be distri-.

buted only t:hen accompanied by a copy of the Review Group's report and a copy of .this statement.

2. Quantitative risk assessment techniques and results' can be used in

he licensing process if proper consideration is given to the results of the ?.evi ew Group. The .staff should use the following procedures re-garding the* use of quantitative risk assessment techniques and. results pe:nding deve1 op:nent of further guidance:

a. In comparisons cif r1sks from nuclear power p1ants wi.th other risks, the overall *risk assessment results of the RSS (i.e., curves or tables of the probability of occurrence of various consequences) sh~ll not be.used

• without an indication of* the wide range of uncertainty c.ssoCi c. ted with those estimates. Any such use should

• nD:e the difficulty of placing high confidence on '

es::imates that are well below. the values set by ex?eri ence. *

b. Quanti'tztive risk assessment techniques m:iy be used tQ_

estir.~te the relative importance of potential nuclear power p1c.nt 2ccid.::nt sequences. o; other f'"atures whe.re sufficient siiuilz.rity exists so that the co.11parisons are not invalidated by lack of an adequate data base. Such techniques should not be used to estimate absolute values of probabilities of failure of subsysteriis unless an adequate data bc.se exis~, and it is*

possib1e eithe~ to quantify the uncertainties or to support a

• • conservative analysis. . .. . * .

. c. Tlie quantitative estimat~ of event probabilities in the RSS shcu1 d not be used as the prfoc:i pa 1 basis for any regu-1 atory decision. However. these estimates 11..ay be used for

• . relatiye coUi?arisons of alternative designs or requirements provided that exp1icit considerations are given to the cr1~1-ci srrts of those es ti mates as set forth in the Report of the Risk Assessment Beview Group. *

d. The RSS conseouence 0

~~de1 shall not be used as the be.sis for licensing decisions regarding individual nuclear power plant sites until significant refinements and sensiti.viti .

tests .alt'. accomp1 ished. However. the consequence rnode1 may be used for relative comparisons provided that such estimates* are not the priiiiary basis for such revie:n*s and provided that explicit consideration is given to the criticisms of the .: .*_.

Various ele;iients of that.model as set forth in the Reoort:of the Ri_sk Assessment Review Group. *

• The st=ff sha11 prepare and submit by June 30, 1979, detailed pro-cedures to ensure the pro~er and effect_ive use of risk assess.ment theory,

et.hods, c

lcta development and stc.tistical analyses by the ~taff. Pending revi el;' by the Co

n

ni ssion of these deta ile*d procedures and the ba$es and rationaie sup;::iorting them~ the Office. Directors will obtc.in the advice of the EDO's Regulatory Requirements Review Coirnlittee should questions

. c.ri se regarding the impl e..lienta ti on of the above instructiOns.

3. The staff shall review the extent to which past and.pending li-

... censing or other regulatory a~tions) including Co;;;-"iiission, ACRS and li-censing board actions and st.at~~ents, have relied on the risk assessment

-~~deis and risk estimates of the RSS. The Co:iriiission hill examine the

• results of this review to determine 1-.*hether the dearee of re1iance.

i~entified was and continues to be justified and t~ decide wbether-re?u12tory modifications are appropriate.

-~. Tr.e staff sha.11 give special attention +o*th~se c:ctivities ider.tifie:d by the*Review Group as being especially ar.renabie'to*.risl(

ass~s.!iient, i.e., dea1ing with generi"c safety-issues~ formulating n5'1 r_egu.1c.tDry requirements.p asses.sing and -re-validating existing r"egu1c.tory r~~uir~uents, evaluating new designs, and fol"1"ilulating reacu:r safety :

ri:::scarch and inspeetion priorities *

5. The staff shall prepare a revie-n' of current. !\RC practices a_nd pro-ced\.J res in* 'b!lo area.s of par ti cul ar conce:-n to the* Review Group:

a. the peer review process for risk assessmen~ deveiopments~

and

b. the coordination ~~ong the research and probabilistic analysis staff and the licensing and regulatory staff, in order to pro~ote the effective use of these techniques.

1ne Co;;;nissio.n wi11 make whatever c_hange.s c.re necessary to assure

• ~Jiat effective peer review and interoffice coordination are integral fectu:-es _of t.:Rt:;'_s risk assessr.ient program.

• 6.* Tne staff sha11 examine the significance of the technical issues raised by the Review Group and the appropriate courses of action for dealing with them. These issues include questions about statistical wethod.s, data base quc1ity and c:vailability, consequence modeling") *

• l hLr.i.an factor considerations, earthquakes, fires$ and -coumon cause failures. The CoITTT1ission will address what changes should be proposed in the approved FY 79 and proposed FY 80 research program to im;:irove.

the data bc.se, including that on hu1:1an behavior. fJ.s c.n addditiona1 c.ction, the staff shall undertake a revieri* of statisticc.1 lil::thods and hu;;;an factor considerations used in risk assessment.

f..ttc Chil:ent:

?.s *stated cc: Cha.irman Hendrie CoITTiiissioner Gilinsky .*

• corrmissioner Kennedy Corrmissioner Bradford Cor;-;iiissioner Ahearne

-Jim~s L. Kel 1ey, DGC

• Y-enneth Pedersen, OPE Jcse~h J. Fovchcrd, OPA Cariton C. Kci.7ii2rer, OCA

. The Risk P.ssessm::nt Review Group, chartered by the l\?..C *in July, 1977

_*to *:provide ad\ri.::e and inforr.ation to the CoCTiiission on the final

• r-epo~t of the Reactor Safety Study, \.IASH-1400," and related r,,a.tte~s, Jj .

_su!J.;;1tted its report to th~ Comnission on Septeiiiber 7, 197.8. The*Review*

• Group, chaired by Professor Harold Lewis of the University of California

- c.t Santa B"arbara, 2/ wc:.s fonned in r-esponse 'to 1 e:tters from Congressman Udc.11 ;.Chairman of-the House Cor.rnittee on Interior- and.Insulc.r* Affc.irs>>

e.xpressing misgivings about the Reactor Safety Stu.dy (1.:f:.SH-1400), and in. :

particular about the "Executive* SLmT.ary" published with the K:.in R::port.

It \-."c.s expected that the Review Group 1 s report h'ould :"assist the Coiiiiiission in establishing policy regarding the use of risk assessment in the regulatory process" and that it would "clarify the achieveITP-nts and limitations of the Rea_ctor ~afety Study.;!!

In August, 1972, the Chairman of the Atomic Energy Corrr;;ission info:l.ied the Chairman of the Joint Corrrnittee on Atowic Energy that the Ato:1iic Energy CoilCiiission had undertc.ken an in-house study "to provide a basis for sub~itting r~co~1iendc.tions to the Congress regarding the .

extension br modification of the Price-A.11derson Act. 11 A draft version of the s.tudy report .,,;as circul c.ted for cOiW:ent in April. 1974.. On O::tober 30, 1975, the Nuclear Regulatory Corrrnissiori 3/ 2nnounced th.at*

-:.:.;.;::.:, __ the final report had been completed. Criticism of the docum~nt fo11oh1ng reli::c.se centered on the method of. treating peer *co_m1:ents on the draft.- .

report as \':'e 11 as on the substance of the report.

• The 1mc press re 1ease

• 2ccornpanying pubiication of HASH-1400 praised the .report, describing it as a "realistic assessment *** , providing 2.n objective and riieaningfu1 esti~ate of the present risks associated with the operation of present da..:,1 1 ight 'n'ater reactors in the United States, 11 gave several comparisons to show that the risk from nuclear power was r.luch less than from other r.;an-r..ade activities, and included a statement that "the final report is a soundly based and impressive work .*** Its overall conc1usion is that the risk attc.ched to the operation of nuc1 ear power plc.nts. is Very 1 ow colii;:iared vrith other natural and man-made risks. 11 y In view of the imPortance a...ttached to the Reactor Scfety Study, within and outside the Com'ili ssion, both prospectively and* after it \<.'C:.S r..ade public, the Corrraission ha*S reexamined it's views regc.rding the St:.idy in lis-ht of the Review Group's critique.

While prds1ng "the study 1 s_ _9::nerc.1 JT:eth8dol_ogy end recognizing .its contri?u~ion t:o *assessing the risks of nuclear por.*er, the Re)*iew Group r.*as critical of the Executive Suj'jj,li~ry, the procedure followed in... producing the fir.=.1 report. 2nd "the ca 1 cul ati ons . in the bod)" of the. reno . rt.*

• . the ~.c.jor fa.il ings

/\.;n::mo- . of the study, the . Review Group cited:.

The Executive Surn:nary: *. The Review Group conc1 uded that "the ..

Executive Sur.rr.?.rY of the RSS is a poor description of the*

• contents of the re:port, *should not be portrayed a~( such, and.

• has lent itself to *misuse in the .. di scussion* of reactor risks. a

• The Review Group i ndi ca ted the EY.ecuti ve* Su;;;:t:fry. does not ..

• cdeqvate1y indicate* the full extent of the_ conseque.nces of*

.reactor accidents and does.not.sufficiently emphasize the

• .uncertainties involved in the calculations of their probability.*

• As c. result, the reader mc.y be left with a r.iisp1aced confidence in the validity of the risk estimates and a more favorable impression

.

• of reactor risks in comparison wi~h other risks than warranted by the study. y The Peer Review Process: Tne Revie\'t' -Group Report criticized the. P..SS staff respons~,_.,p_ointing .. ol!t*:that. in ~ome cc.s_es cogent cor.;r:::nts from critics either were not acknoh'1edged or were evc.oed.

c:nd that. iri general. the record of response tO val id criti ci srri.

• h'~s 'n':::c.ker than it should have been. Tne Report points out _

that the lack of clarity of WP.SH-1400 itself 1ed*to major diffi-

• cul ty in tracing a 1 ine of thought through the study and crippled rnany efforts to .accomplish responsible peer . reviews.- .

Accident Probabilities: The Review Gro'up wc.s unable to deter-mine whether the absolute probabilities of accident sequences in f:P.SH-1400 are high or low, but believes that the error .

bounds on those estimates are, in general, greatly understated.

This, the Report said, is true in pc.rt because there is i_n Tii?.ny cases an inadequate data base, in part because of an ir.abi1ity to quantify corrrnon cause failures, and in part becc.use of some:

questionable methodological and statistical p~ocedures *.

.The Review Grouo also criticized, in some cases severely, various of the calculation.al techniques in tlie Study e.s well as its lack of clarity *.

• -. The Review Group cited the fol lowing as major c.chieVe!il::nts of *the study":

"¥:ASH-l 40D was a substantial advc.nce over previous attempts to estiraate the risks of the nuclear option.

"~!ASH-1-400 1-,*::.s larg::ly successful in at lee.st three 'ri"a,Ys; in mc.l:ing the study of reactor safety mJre rational, in

• estc.blishing the topolo9.)' of Iii2.ny accident*seouences, and in del ineatina orocedures thtouch which ouan*dtc.tive esti1..=.tes Of the risk *can' b;;; derived for those seauenccS for h'h-'i ch a data base exists. *

-,*?Despite. its shortcomings, WASH-1400 prov1aes at this time~

t!)e r,iost complete singl_e picture of c.cci d:::nt probabilities * .

cssociated vlith nuciear reactors. Tne fault-tree/event-tree  :

approach coupled* w"ith an adequate data base is the best available tool with \'.'hi ch to quantify ~hese probabilities *. ,

• _*

"l<:ASH-1400 r,iade c1e:ar the im?ortance to reactor safety dis-

• . cussions of accide~t consequences pther than early fatalities.~

The Com;ni ssion accepts these findings and takes the fo11owi_ng actions: * * *

!:xecuti ve St.::7:7ia;--y: Th:: Co:::7ii ssi on withdrav.*s any explicit or implicit past endvrsement of the executive Su;;;;,ary.

The Peer Review-Process(* :The Co;;ui:1ssi_on:2g~es. that. the~,:-*.*;."::.

peer revierr*process fo11_ow2d in publishing wi:.sH-1400 was'-- . :

inadequate and that proper peer review is fundamental to ma}:ing sound, technical decisions. The Com:nission wi11 take whatever corrective action is necessary to c:ssure that effective peer review is an integral feature of the NRC's risk cssessrnent program.-

fa.ccident Probabilities: 1ne Co;;,;nission *accepts the Review Group Report's conclusion that absolute values of the risks presented by WASH-1400 should not be used uncriticc.lly either in the regulatory process or for public pol icy purpos~s !=-nd .

has taken and wiil co11tinue to take steps to c.ssure that any such use in the pc: st wil 1 b~ corrected as appropriate. In

_pcrticulc.r, in light of the Review Group conclusion*s on accident probabilities, the Corii:iiission does not regard as reliable the

. Reactor Safety Sturiy's numerical estimate of the overalr risk of reactor 2ccident.

CoiTLilunication \'lith th'e Congress and the* Pµblic: CoiTiJilission correspondence and statements involving ~AsH-1400 are being reviewed and corrective action as necessary will be taken.

-lr-

}!iti) respect to._the coiilponent parts of the Study, the Coi7.:"iiission e:x:;::cts the staff to make use of them as appropriate> that is, wher& the d~~a base is ac:lequate and analytical techniques p::r.nit. Taking due accc*!.mt of the reservctions expressed in the Review Group P.eport c..nd 1n its presentation to the Comission, the Coi"i"i:iiissfon su?ports th~ extended use of probabilistic risk ass_essment ~n regulatory decisionmakfog.

Th"e Comi ssion has provided additional detailed instructions to the .NRC

. staff concerning contin.ued use of risk assessr.12nt techniques Md results

.*in response to specific criticisms raised by the Risk .fi.ssessment Review

• G~up. . *.

fiOTES JJ. Its c:h=. rt er rec.ds: *_"The Re vi evl Group ini l1 pro vi de add ce-:-and fofo~:=.tfoii to the CD:7riiissfo;J r.::9c:.1dfo9 the fir.c:1 1c::r;c:rt of the. R,;:c.ctor Safety Study, K!.--S?-1-1400> and the pe.er c::;~::.:-;ts on the Study, c.dvice c.nd. reco;;;;:"'=ndatfons on deve1oprr:-::nts in the*

fie19 of risk cssessment ii":ethodol ogy and on futu;e cour-ses of

~ction 'r.'hich should be tc.l:en to improve this rrr.:thodology G.nd

--..... its cpplication. This advice and infor.;;~tion will assist the Cor.-:nission in estc.blishing policy r-egarding th~*use of risk assessment in the regulatory process, in improving the base for the use of such assessments. It wi11 aiso cic.rify tbe .::chieve-fi'.ents c:.nd 1ir.ritations of the r,eactor Safety Study. 11 Y* The .other rr.-=mbers were Dr. Robert J. Budnitz (Lawrence Berke1.ey Laboratory, University of California), Dr. Herbert J. C. Kouts*

(Brookhaven National Laboratory), Dr. ~:alter Loe\\'enstein -.

(Electric Power Research Institute), Dr. ~illiam Rowe {Environ-

!ilental ?rotection .!.9ericY), r;,. fr:::.nk vor, Hi;:;pel (Princeton .

University) and Dr. Fredrik Z.:charic.sen (Cc.iiforriia Institute*

of Tech:1oicgy). Dr. Budnitz ~s pre_sently on leave froiil the University of Ca1ifornia and is serving (since AugL:st 1976).c:.s Deputy Din:ctor cif the rmc's Office.of NuclEar Regulatory .

Research.

The Nuc1e.ar Regulatory Co!'i'i:iiss"ion 'n*as estab-lished on Jc.nuary 19, 1975 to carry out the regulatory functions of the Atomic Enero_y Corrrnission> Hhich 'n'as c.bo1 ished on that dc.te.

~ The press re1ease at the time of public2tion said that the report is the culrainc.tion of the mJst comJrehensive risk assessraent of nuci e.c.r pol'.*er pl ants r..c.de to date. TI-1e objectives of the study h'eie to iiie.ke a reaiistic 2ssessr;;-;;nt *.** Tne overall conclusion ... is that the risks 2ttached to the operation.of present d2y nuclear por.*e:r plc.nts c.re -very low co;;;:;:ic.red to other natural and rn~n-made risks .*.. Nuclear power plants* are about 10,000 times less likely to produce fatal c.ccidents than man-made non-nuclear activities ...* !~on-nuclear ai::cidents-invo1ving CDii1Jarc.bie le.roe-dollar v21ue d2maoe are 2bout 1,000 times rn:::>re l_ikely than nuclec.r.pol'.*er plant accidents ...* Tne chance ,

that a "p::.rson living in the 9e:nera1 vicinity of a nuclear por:er

.Plant wi11 be fatally injured in a reactor accident is one i~

five billion per year **.* In the event of an unlikely reactcir c.cci de:nt rr'ith a probability of one in a mil lion per reactor per

)~ear, le.tent health effects except for thyroid nodules r.*:::;uld be

• such c. Sii.::.11 p:::rcent~ge of th:: nomal 'ir.cide1it rc.tes that they

\','J~id b::: c~fiic!Jlt to d:;:t:::ct ...*

11

~ ' ' .

Tne li?.C Ch::.imi=.n \..'as quoted as saying, "The Co;:::;ission be1 ieves thc;t the R.e2ctor Safety Study R:::port pro\'ides En o~jective and meanincful estimate of the oublic 1f sl:s c.ssocic.t2d 'nith *the operc.tion of present dc:y 1 ight \*1cter reactors in. the U:-1ited States.... The final r~poft is a soundly based and im?ressive work ....

Its ov:ra11 conclusion is that the risk attached to the cperc.tion of nuci2ar pD't.'er plants *is very low co:qar:ed

~ith other *natural. and man-!iiade riskso 11 - Tne press :

ie1ease went on to say that ~~r2 than 1800 pages of co:;ui::nts w:re received from a broad spectrum.of people and all were carefully considered in preparing the

-. .- 7ine.1 report. ~ * .

• Professor Lewis, in reporting*to the Corimission.~ said that the Executive SUiiLTiary was not a surrrnary of the*

report. He concluded it has written as a public s:.::te~~nt tr,c.t rec.ct.ors w::re safe comucred to other 1_isks .to 1-.*h~ch th:: pub~~c is t:/':po~~d ~rid h:: stat~d it_, .

s~oula not nave been ett=.ched to ~ne rep~rt and oescr1aea c..s c. part of it.

. *... *  : * ! *:: ,: ,'.._':"":'" ...  ;. . ... : ~ ..*.

• -- ** .....