ML20055D310

Summary of 900208 Meeting W/Epri Re Contents of App a to Chapter 1 of EPRI Advanced LWR Requirements Document.List of Attendees & Slides Presented at Meeting Encl

ML20055D310
Person / Time
Issue date:	06/20/1990
From:	Kenyon T Office of Nuclear Reactor Regulation
To:	Office of Nuclear Reactor Regulation
References
PROJECT-669A NUDOCS 9007060149
Download: ML20055D310 (22)

Text

,

June 20,1990 4.

Project No. 669 APPLICANT:

Electric Power Research institute PROJECT:

ALWR Requirements Document

SUMMARY

Of MEETING TO DISCUSS APPENDIX A TO CHAPTER 1 0F THE EPRI ALWR REQUIREMENTS DOCUMENT On february 8,1990, representatives from the NRC and EPRI met to discuss the contents of Appendix A to Chapter 1 of the EPRI ALWR Requirements Document, "PRA Key Assumptions and Groundrules" (KAG). is the list of attendees. Enclosure 2 is a copy of the slides presented during the meeting.

During the meeting EPRI discussed their general philosophy in the development of the document. EPRI indicated that its function-level PRA will be used to show that EPRI has resolved issues on a general level, but that the design-specific PRA will be expected to demonstrate the validity of dasign modifications.

EPRI indicated that the KAG primarily addresses full power events. Although there are a few criteria in the Requirenents Document to reduce the probability of low power reactivity accidents, EPRI has not done an extensive evaluation for such events. The staff indicated that it is assembling guidelines to be used to address low power accidents, and that EPRI (and/or the vendor) will be asked to address them upon issuance of those guidelines.

The staff asked EPRI how they incorporate the human element into this document. The applicant indicated that they attempted to reduce the need for direct human action to recover from an accident or increased the time until action is required by the operator during such an event.

The staff _ recommended that EPRI should provide a set of hardware reliability values to be used by the designer in determining where to direct his design efforts to improve the design of the plant.

At the close of the meeting, the staff indicated it would review the Chapter to determine if the assumptions were acceptable to the staff and agreed to provide recommendations in those areas where the staff falt needed clarification.

/s/

Thomas J. Kenyon, Project Manager Standardization Project Directorate Division of Reactor Projects - 111, IV, V, and Special Projects

Enclosures:

As stated E:

0- '

cc w/ enclosures: See next'page 9[

ICentral F.ileT3 DISTRIBUTION:'

~

NRC PDR FMiraglia" d

n, og JPartlow PDS Reading l-o n:

TKenyon OGC I

y' articipants 0)

M k hh hh i

o ca o --

PD :L PDSy D:PDS (,-/wd

~

O P,,

TKen.

n:cw CM111er 06 4\\

0 06 g 90 06/W/90 j

MTG StfiMARY ON APP A

,e'p3EtspN UNITED STATES l

[

C(/[,t NUCLEAR REGULATORY COMMISSION g

I W A$mNGT ON, D. C. 20Mt>

i June 20, 1990

....+j Project No. 669 APPLICANT:

. Electric Power Res6 arch Institute PROJECT:

ALWP Requirements Document

SUMMARY

OF MEETING TO DISCUSS APPENDIX A TO CHAPTER 1 0F THE EPRI ALWR REQUIREMENTS DOCUMENT 0:1, February 8,1990, representatives from the NRC and EPRI met to discuss the contents of Appendix A to Chapter 1 of the EPRI ALYR Requirements Document, "PRA Key Assumptions and Groundrules" (KAG). is the list of i

attendees. is a copy of the slides presented during the meeting.

l

- During the meeting, EPRI discussed.their general philosophy in the development of the document.

EPRI indicated that its function-level PRA will be used to show that EPRI-has resolved issues on a general level, but that the design-i specific PRA will be expected to demonstrate the validity of design modifications.

EPRI indicated that the KAG primrily addresses full power events. Although there are a few criteria in the Requirements Document to reduce the probability i

of low sower reactivity accidents. EPRI has not done an extensive evaluation for suci events. The staff indicated that it is assembling guidelines to be used to address low power e,ccidents, and that EPRI (and/or the vendor) will be

asked to address them upon issuance of those guidelines.

The staff asked EPRI how they incorporate the human element into this

' document.' The applicant indicated that they attempted to reduce the need for direct human action to recover from an accident or increased the time until

~ action is required by the operator during such an event.-

The staff recommended that EPRI should provide a set of hardware reliability values to be used by the designer in determining where to direct his design effor_ts to improve the design of the plant,

,At the close of the meeting, the staff indicated it would review the Chapter L

~to determine if the assumptions were acceptable to the staff and agreed to provide recommendations in those amas where the staff felt needed clarification.

^

g,-

ow

~

Th s J. Kepy n, Project Manager 1

Standardization Project Directorate Division of Reactor Projects - III, IV, V, and Special Projects

~

Enclosures:

As stated ccc w/ enclosures:- See next page

h 3,

Project lio. 669 EPRI ALWR Utility Steering Committee cc: Mr. E. E. Kintner, Chairman Advanced Light Water Reactor Steering Comn.ittee GPU Nuclear Corporation 100 Interpace Parkway Parsippany, New Jersery 07054.

Mr. John DeVine. Jr.

Nuclear Power Division Electric Power Research Institute P.O. Box 10412 Palo Alto, CA 94303

'i

.i i

'?

Meeting Attendees Appendix A to Chapter 1 of the EPRI ALWR Requirements Document February 8,1990 anization Org/PD$[t

Name f4RR Thomas ~Eenyon Brad Hardin RES/DRA/ARGIB Jerry Wilson RES/DRA/ARGIB Stuart Lewis-SAROS, Inc.

Bill Sugnet EPRI Manie Pohida NRR/RAB Maurizio Colagrossi ENEA Jean-Lue Caron C.E.A.

D',b Youngblood Brookhaven Adel El-Bassioni NRR/RAB Jean Liaw NUS Corp.

Tom Ryan HFB/RES/NRC A. H. Hsia NRR/PDSLE E. S. Che111ah NRC Susan Gray EPRI John 1 rotter EPRI 1

Dave Leaver Tenera L

Masazumi Muraymama NRR/RAB r

t

M l~

l l

d-(

\\

l' o

1.

l i.

m._.,.

L ALWR r

L REQUIREMENTS DOCUMENT c

PRA KEY ASSUMPTIONS AND GROUNDRULES i

I i

W. R. Sugnet S. T.^ Gray c

?

S. R. Lew's i

J. D. Trotter-

. t.

1

.!\\

i e

lbN

.4 i[

h jk.

i f

o, I

I utilhy / EPRI i

i i

ALWR REQUIREMENTS DOCUMENT l

PRA KEY ASSUMPTIONS AND GROUNDRULES P

W. R. Sugnet S. T. Gray S. R. Lewis J. D. Trotter Advanced LWR Program

(

i l

?

UtIlhy / EPRI ALWR REQUIREMENTS DOCUMENT STRUCTURE j

vcLu.ta.1 ALwn.TO.P. TIER

.EXECLmyt tuuwARY

. ALwR POLCES e ALWR HEY RE00stEWENTS i

l n

-t

[ voLuem a. PAtevt PLAWT ALwn REcutRf.4dlBr*5

+

VOLuest a. EvcLUTIONARY PLAwT ALwn mammmMTS

• TER 1: OVERALL PER80RW ANCE i

AND DE SIGN REQUIREMENTS CHAPTER h OVERALL PERFORMANCE poR PassrvE ALwn AND Df!'3N 9tEQUIREMENTS PLANTS FOR EVOLUTIDNARY ALwm eTER t.13: REQUIREWENTS FOR PLANTS SYSTEWS AND STRUCTURES 3YSTE 8 NO TRJCTURES Advanced LWR Program ennno me

?

-.s

,~n,..-,.

. + - - - - -, -, ---, -

,.ow, u-w,,---,-w.

- -m-,

g,

)

1 i

Utility / EPRI SEVERE ACCIDENT PROTECTION Thraa Kev Elements:

J

1. Design to meet applicable Regulatory Requirements i

. covers liosraing design basis,

provides significant margin

2. Emphasize core damage prevention target core damage frequency, s 1 x 10 E 5/ reactor year

. provide addhional preventive foetures to protect utility investment

3. AnaYze cominant SA sequences to show sufficient margin:

. conservative design (e.g., containment design pressure)

. Investment protection features (e.g., increased RCS inventory) j

. plant features that aid in SA mRigation (e.g., cavny arevarrangementmooding RCS vont valves)

. realistic, mechanistic evaluations including non safety related equlpment Advanced LWR Program l

1 Utility / EPRI

~

ALWR Program PRA Activities

. Function l.evel PRA Evaluations

. Test design capabilhy to meet the overall safety crheria 1

. Feedback to design requirements on effectiveness of design ahernatives

• PRA Key Assumptions and Oro:ndrules Document

. Define the important assumptions and reach closure wth NRC

. Use in PRAs of oortifcation designs to i

demonstrate that overall safety criteria are met

]

Advenood LWR Program l

I 1

g

t r

4 7

l Utility / EPRI ALWR Public Safety Criterion s

• The erherion was selectnd based on a number of considerations a desire on the part of utiltty sporriors to def.no an ALWR that is excellent in all respects

. an accident frequency less than 1 x t0 E 4 por reactor year is believed to be low enough to satisfy this desire for exallence and the pubhc perception 25 Rom at the alle boundary is a very low dose with 'no observable heahh off acts' (10CFR100)

A design that meets this criterion will meet the heath ef fect goals in the NRC Safety Goal Policy by a wida mamm I

• Preliminary ustimates based on exishing plant PRAs indicate that an improved ALWR whose dominant accident sequence frequencies are reduced has good likelihood of meeting this demanding criterion Advanced LWM Program f

Utllity / EPRI Demonstration Method

-t Portorm PRA, obtain Release Categories and mean frequency for each Perform ORAC-type calculation for each Release Category, obtain spectrum of whole bod doses at 0.5 midependent on weather (and as conditionalprobabili )

Use resuhs to construct CCDF

• risk curve' for dose at 0.6 miles No points on curve allowed to exceed both mean f requency of 104/ reactor year and 25 Rom Not -

10 5 -

Allowed i

L Mean go.6 -

Freq, 10 7 - -

1b ib 20 2b Rom Advanced LWM Program 4

4

+

i 1.hlilty / EPRI r

CORE DEBRIS COOLABILITY Concern is that detelis bed will continue to attack concrole, e

overpressurize containment, produce more combustible gases, 1

and eventually fallcontainment r

ALWR Treatment

. Ensure that debris can be covered by large amount of water

. Gravity drain from suporession pool (BWR) / IRWST (PWR) accomplishes inhial f bodin0; refill connections for long term l

Severe accident evaluations will consider that debris has been electively cooled if covered by large amount of water Advanced LWR Program o

i Utility / EPRI CONTAINMENT VENTING l

Containment ventin has been discussed as a potential means to e

prevent containmen failure.

Some European countries have installed vont systemst no coherent l,

dosi n basis has been developed; various design capaobes and fint on systems have been employed ALWR Program philosophically opposes design to vont containment e

Rugged containment with high integrity is a line of defense against accident effects; philosophically undesirable to bypass containment by design

. Design for venting large number of curies of noble gases is undesirable.

- institutionalviability of design for venting cannot be assured; potential consequence of delaying a project downstream poses too much risk Advanced LWR Program l

1'

,m

,,.e.,--

ev.,

e

.a..

.,w

l

[ utMty/EPRI D

--\\

Utility / Electric Power Research Institute j

t ADVANCED LIGHT WATER. REACTOR REQUIREMENTS DOCUMENT l

i OVERVIEW OF THE PRA KEY i

ASSUMPTIONS AND GROUNDRULES i

I i

Stuart R. Lewis

~

SAROS, Inc.

l l

February 8,1990 l

1

==ces twn m uncuo mo s-i l

Utility /EPRI

)

~ '

NATURE OF THE GUIDANCE PROVIDED IN THE KAG DOCUMENT Identifies minimum content for PRAs by plant designers to achieve goals cited earlier Provides guidance commensurate with perceived need for definition, e.g.,

Limited discussion of modeling of systems and sequences, since methods are well-developed and reasonably straightforward to use; but More explicit discussion of acceptable approaches for human reliability analysis and treatment of common <,ause failures, since these vary much more from PRA to PRA Intended to promote use of state-of-the-art methods to obtain realistic characterization of risk and risk contributors Attempts to identify areas in which detailed analysis is not necessary to achieve goals (e.g., intemal and extemal flooding) advances I.wn prayam Y NFE KAG 2/90 S-2

unwraem

)

DISCUSSION OF METHODS EMBODIED IN THE KAG

(

j For perspective, KAG methods are summarized relative to the methods used in the analyses performed for NUREG-1150 l

4 KAG Document MUREG-1150 S

Topic: Scope of the Ar,#-45 l

7 includes assessment of core <famage Similar overall scope, but with examination of frequency, containment response, magnitude several measures of offsste consequences and frequencies.of releases, and limited assessment of offsete consequences Requires examination of internal and extemal Examination of internal events and, for two i

events, although rationale that may be applied plants, earthquakes and intemal fire i

in' excluding some extemal events from detaded analysis is provided Examination only of events imtiated nominally Same l

from full power (i.e., risk of events occunirg at shutdown is excluded) l Limited uncertainty analysis, aimed at ensuring Very extensive uncertainty analysis important risk contnbutors are understood t

Advanced LWR Program NRC KAG 2/90 S-3 l

J# +-.

m m

._______..___=___y_._

__.___.,____.._m.m

-.m m..

m..

______.m.;_.__I

p Utllity/EPRI

~ }.

KAG METHODS (continued) l KAG Document NUREG-1150 l

Topic: M6deHng of Systems and Sequences i

KAG is not explicit with respect to modeling Event trees with top events generally eppieerfi; calls for models that can produce corresponding system-level failures; key top l

sequence-level identities cs.T.pii=ed of inmatmg events developed through detailed fault trees t

events and combinations of basic events Success enteria intended to be reahstic, with Similar guidelines used in selecting success conservative entena used for areas in which cWmiia results and insights would not be affected t

Topic: Selection of initiating Events Comprehensive lis* of intemal initiating events.

Same general approacJi; intiators grouped into l

based on past PRAs, other studies, and detailed limited number of general coimyt.es review of sysimirspecir.c inmators Seismic events and intemal fires selected for Specific inclusion of seismic events, and more limited s..siysis of tomados; other extemal analysis on two plants based on past PRA -

(

events generally can be excluded based on experience design features or low occurrence frequencies l

l I

i I

i I

i j

i i

Advanced LWR Program

}

NncKncmosa i

~

urunr m m

KAG METHODS (continued)

~

o KAG Document MUREG-1150 Topic: Treatment of Dependent Events i

Explicit modeling of hardwired and funchonal Same intersystem dependencies l

Same general approach l

Modeliig of mmmon failure due to shared root causes at the component level (using methods outlined in NUREG/CR-4780) i Generic failure rates used for most components

[

Quantification of common-cause failure events based on detai!ed review of generic event without detailed review; plant opedric reviews summaries, with option to use data base made for a few w...pvi=

developed for PRAs of ALWR design requirements Human actions involving dependencies to be Same general opp Ord.

i l

handled within human reliability er&tysis i

l t

l Topic: ReAiabdry Data j

l Generic initiating event frequencies

[

i Initiator frequencies based on exarWiehon and application of experience for exist agwWds i

j Component failure data based on generic Generic data, with plant-specific data for events j

l sources (a basic data base is provided) that are unique or of simdid ' nportance w

i, i

I i

l Advanced LWR Ft+ :-.

l tecxAG 2r90 s-s

_l i

i l

r

i

l

!!jij' jl

[ji lj4jl

'i'

^

- h h

n t

y u

t r

i n

t c

w a

i a

l r

ib e

s g

i m

d o

c e

p u

s a;t n

c n

il h

u e sn e e

n P

f i

r o s u

e n

p p

ei n q

u R

n a

mtc o e

q V

e ia p s

e 9

P s

y s

L t

t

i. e f

a R

d d

i i

l c

r t

l E

e m

n ae d d

0 i

i n

a n

e e

f f (

5 h

H i

vi u

dia l

i

)

n T

p s

c f

1 i

d d

ma n q

et t

e c

o d

mre n

n d

1 a

a i -

e sii n

r i

oe u

v e

G o

mtc a

i q

d f

t h

h f r E

ra e

n e

s A

r u

R d

m wt p

t i

i o

pw e

r i

,sf a

n U

a s

ho t

i n4 a

t s

b N

e t

r g

cmis o

o0 s

i t

s p

n a

sR it 1 0

o y

a e

r i

p c>

g aW o ol i

s a

s n

ly s

u p

nB

0 d

ns a

t r

f n

t M-e uie m

o d

p 6 o

a n

n ei e

a ;0 a ro s

rt c a

df u

in d l t i

c A

ac s

r

(

y va e

s a ;a e S S

ee

e l

u t

eiW M

ue me l

ir i

a Ts q n r a mt s

qt a

s iceT u

Et i, e a

n e

l b

Ei S A Scda Q

Ss Sf P r a

S He e

D R

cn n

c e

o O

t u

i a

t t

m a

n n

q d

gio e

e u

hm a

H H

ce dlp nt S

ifi e

ia t

ats T

oy

in sl n

l f

r 1 o ue c

e h

a r

us c

ps 6

r i

v t

i p

pt sd do p

e w

qis E

i o

a n u e e c o

l ely i

s f

e ga iy T

e d

ba M

T Pla eb ni t

c e

n t

n o a t

Rv t

l d b ai e )t t

n Au e

oP d i

t ub i

e Hq d tRe qia un m

de qe r

ec G

m Se u

sEz eele l

ela e

in r

r y brd s v p

ue u

n c

oHl l

c n o x

nTa o eo nu y

qu i

A o

o e

iq c

eq mm n

t r

a n

r e esa si D

do n

a n

R b

e ss e

t K

t e

o n

g r

u en og o o q

sI G

aR s

ahn inC i

o t

mciue ciH o (s e ac t

A bP s

t t

t i

u sb ac r

sh K

eE mh e 's ne t

f tgi by mt dt nfeR a

os n

t l I w

o' ob o

noh e rP uu nt i

m t t tde c

eht d s

e t

l i

ieo ihE oc on d

ger t

f

&i c

a npu o

cmt c c s sl i i t

c r

a a a a

a a n

iod lel e s

l r

o emct a gla d

t dec o

r t rh ni spc di ns nr 4

vo ei m o p u oin un a o m

o er n

o s

r s r o Mdp E Pus Pas MmTc Pc 0

l i

ru 9

/2 G

AK C

RN l

~

Utility /EPRI f

~

KAG METHODS (continued)

~ KAG Document NUREG-1150 l

i Topic: Ar%s;5 of Sersnic Events l

Seismic analyses nerformed for two plants, using Seismic analysis required. based on reference site seismicebes (calculated using EPRI two sets of site-speofic seis,,,; cities (LLNt_ and methodology); most sdes in Eastem U.S.

EPRI.Tmit.000 loges) covered Modeling of plant systems and structures to Same include seismically-induced failures and i

important " random ~ faults Similar approach used

[

Fragility values offered, based on examinahon of existing studies and companson to ALWR requirements; opbon remains to perform design-speciT,c fragility analysis 7

Response F.e;ysis simplified relative to SSMRP, Response en# sis based on s;,,4Cd assumptions (e.g., complete coupimg of like but retained location-spedisc weerations and j

cer.penei.is :n same system) inter-component consbtions l

Quantification requires tracking dependencies Same eppfwii -

i k

e Advanced I.WR Program NRC KAG 2t90 s-7 l.

L i

,g-..-

urnariem KAG METHODS (continued)-

c i

KAG Document NUREG-1150 Topic: Andysis of Other Extemal Events i

Tomado analysis required for extended loss of Tomados excluded on the basis of judgment that offsde power risk ~was low i

i Rationale provided for excluding evaluation of Simplified fire analysis performed for two plants fires (due to extensive requiremerps for separation, eliminaten of cable spreading room.

etc.)

Rationale suggested for excluding other Other events excluded based on judgment that extemal events, based on design features, low risk was low l

occurrence frequences, etc.

~

i i

?

Advanced L9VR Fu-g....

i NRC MAG 2/90 M

-l

{

~

[

~

il;!i![li!

,i i

II! !:!!!

t t'.i

!h!t

=

1 6

d s

s t

d nd &-

y n

e eo b

a f

s cin c o

r a r a a c r

a g

t t

bul

,r a

n e

o ooaie sp e

g sa r

esS p nh e

ndr at e e m

m un P

a e

t f

i g:no s

oam o

r t i o exp at e

nmo R

t r

i y

x pt er g t

sm,ai nl nh e

or n W

n io eni eisis t f e L

viap m

a

,h v

cgomu rl n

enrf o

t n

iep d

s eeo 0

r i

i f

bv e

nbst l

v c 5

ui min c

e

)

adarc si nn n

dug w

o na n

1 l

uufoe d

r n

f f a a

ctet a

1 dlclc f

r de l

e ior r

x v

yna e

G hic a

d n

c e c e

mf yt nd o

e n

d E

i l

6 oa y

hu A

u R

nego e pf aser o dioh W bs dt t

eiy ar c swe n

U n c af p o gb a r

N s> euke s nl hf c r

t a

,k ho cpr eeso i

i r

s a so dve p

t 3,

t t

n uo Pef e vn p f

o pf i

n t

0 of cl noa n

o e ss c ;i nt i

iu i

e A

n ydlyn ad eao m

c an t

t a; p o

ot oaio e

rt d pi e l v

e heCnt n

i ;;c i is f

c a

e osda an al h

s t

u eir ae l

n ua n ye r

i l vm mc ae sg i

t

(

o a

at l

wne nd ap r

t v ou u nx l

p vneoa eexot s

EoTf c Ddeci Cs Qae r

n t

e S

R D

tn e

m r

O m

e o

r f

n b

f n e

oo o

e t

s ia oh H

i e

t t

t t et t

a c

s a

i n

ews c dar T

o s

ui e nut s

m i

C n d ;i ceo o y h f

t t

E oees omsn ela s

ptnaj ioda bn e

t u

v c

s ei M

d t

m ph n n nn oa s

ip e

r eae c

e t

r t

o t

o ce oiw ch gm yd b n

T i l r

t pp pno ce n

i l

e e

u ppe bddn ae o

i G

m a uab na e

.pp l

r u

ds s a o ao h as dsee p

c-n sb i

t A

c y,a p

l etst o

hPAs w

en ng aig al l

i D

n rs bi l

K aAo n,

n t e eiP ue ea r

b m

vmduA cd bb rMb i t

t G

nenl A u

A e

as et moro gl a c i

K hn u &-

vnt nM r

t t

t c

eani so p

i y

r n

f sl c t

ot,b I

ou a c n ocn tfn ot t

r n

c R

ndl e epo ed ed it i e

ao P

oeav mmt me mn cp i

imnt nign s ni E

i -

t f

s imih a

oa at i

/y ni t

a nc r

ciae oim u

i r

t t

t and ne an 9

afde nlet t r l

ti of od ot ua S

r l

vedt l

e r

t t

E pa a Cee ca Cd Qb 0

i r r 9

U

/2 G

AK CRN

. ;i i i j j!!

i1!'

,1 l

1 Utility /EPRI f..

KAG METHODS (continued)

~

KAG Document MUREG-1150 Topic: Sotuce Tenn Antis;s Source terms estimated using paiosmi.;c models Source term calculations to be performed using l

MAAP, with other tools perm 4ted given to merme detailed code calculations, with key appropriate justification p&oismies determmed from broad expert l

opinion sohcitation i

Topic: Consequence Analysis Offsite consequences to be estimated based on Consequences estimated for specir.c sites, in I

enveloping site meteorology and demography some cases substitutes for actual plant site l

characteristics Calculatons performed using MACCS for CRAC2 or MACCS codes to be used to perform analysis; only site boundary dose required to be several measures of offsste consequences calculated t

Best-estimate modeling of evacuation performed.

For c+T.pa -is06 to EPRI high-level requirement.

l no evacuation assumed for 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> assummg 99.5% p&iscipai;vn; sens:Imty studres f

performed for other assumptions on evacuabon i

i

)

i t

f 1

Advanced LWR Program NRC KAG2/90 s-10 l

=

y' utmerment KAG METHODS (continued)

~

KAG Document NUREG-1150 Treak,ciit of Uncertainties Topic:

Attempt made to quanhfy uncertainhes at every Explicit propagation of uncertainhes not required; sensdnnty studies called for to phase of the analyses except offsite examine key inputs and pigvide necessary consequence analysis engineering inseghts into key risk contributors

- Traditional pupagation of variabritties in data

- Use of expert opinion on uncertain issues to examine effects of modeling uncertae

- First-of-a-kind effort with inspect to depth of treatment and formalization of input based on expert opinion Advanced LWR Prograrn NRC KAG2/90 s-11

~

0-

[ UtilityMPRI.

?,

SUMMARY

KAG _is intended to promote performance of state-of-the-art PRAs KAG-directed PRA should be essentially equivalent to studies performed for NUREG-1150, with notable exception of level of detail in uncertainty analysis KAG is not prescriptive regarding methods in most areas, but allows flexibility for designers to apply appropriate methods with which they are most familiar Focus of methods in KAG is on use of PRA to achieve improved engineering understanding of key contributors to risk and to identify any aspects of the design that merit improvement Adysreced L9FR Fr@ax NRC KAG 2f90 S-12

.