ML20211C389
| ML20211C389 | |
| Person / Time | |
|---|---|
| Site: | Seabrook  |
| Issue date: | 05/24/1984 |
| From: | Mattson R Office of Nuclear Reactor Regulation |
| To: | Ogeka G ENERGY, DEPT. OF |
| Shared Package | |
| ML20209C800 | List:
|
| References | |
| CON-FIN-A-3778, FOIA-87-6 NUDOCS 8702200085 | |
| Download: ML20211C389 (27) | |
Text
I 4
s Mr. Gregory J. Ogeka, Chief Administrative Branch Brookhaven Area Office U.S. Department of Energy Upton, New York 11973
Dear Mr. Ogeka:
SUBJECT:
BNL TECHNICAL ASSISTANCE TO THE DIVISION OF SYSTEMS INTEGRATION, NRR, NRC, " Review of the Probabilistic Risk Assessment for the Seabrook Nuclear Power Plant" (FIN gj?7f)
The enclosed NRC Form 173, Standard Order for DOE Work (Enclosure 1), is hereby submitteo in accordance with Section III.B.2 of the DOE.NRC Memorandut of Unaerstanding, dated February 24, 1976.
The enclosed order provides funding authorization in the amount of $50,000 to begin preliminary work in accordance with the enclosed Statement of Work (Enclosure 2). Please submit a proposal to provide technical assist,ance to the Division of Systems Integration, NC sorougn Fi-55.-Enclosure ((deTailsthe required work and should be used as the basis for preparing the proposal for submittal to this office.
Standard Terms and conditions for NRC work, as provided in the DOE /NRC Memorandum of Understanding of February 24, 1978, and described in NRC Manual Chapter 1102, should be used as the basis for preparing a proposal. If a.per-tion of this work is to be subcontracted, it is required that BNL have a pro-fessional assigned to the contract who is qualified to defend the results.
Also, prior approval by me in writing is required before initiation of any sub-contractor effort. Please submit a proposal containing, as a minimum, the in-formation set forth in Enclosure 2 in the format of the Statement of Work within 30 days to:
Mrs. Sybil M. Boyd, Program Assistant Division of Systems integration, P-1102 U.S. Nuclear Regulatory Commission Washington, D.C. 20SSS $J//- 87'd 6.
05/24/64 1 LETTER TO OGEKA W/ ENCLOSURES 0702200005 B'70211 PDR FOIA PDR SHOLLYB7-6
1*
s This work is to be started immediately due to the need for a coordinated program with Lawrence Livermore National Laboratory (NRR/OST funding, FIN No. A-3754-4),
which provides the " front-end" portion of the evaluation.
The balance of the funds for completion of the project will be provided incre-4 mentally at a later date.
If you have any questions concerning the acceptance of this order, please I-contact Mrs. Sybil Boyd on FTS 492-7685.
Sincerely, I
i Roger J. Mattson, Director Division of Systems Integration j Office of Nuclear Reactor Regulation i
Enclosures:
- 1. NRC Form 173
W. T. Pratt, BNL p1 M. Khatib-Rahbo6$ BNL R. Bauer, 00E-CH R. Barber, DOE-HO j
s I
1 I
l, h
l i
i 2 LETTER TO OGEKA W/ ENCLOSURES t 05/24/84 P
s Enclosure 2 STATEMENT OF WORK
Title:
Review of the Probabilistic Risk Assessment for the Seabrook Nuclear Power Plant FIN No.- dt?' 1'7 5 B&R No. 20-19-40-41-3 NRC Project Marager: Warren C. Lyon (FT5 492-9405)
BACAGROUND The Reactor Systems Branch has the responsibility to assist the Reliability and Risk Assessment Branch (RRAB) within the Of fice of Nuclear Reactor Regulation (NRR) in the review of Probabilistic Risk Assessments (PRAs) submitted te NRC by license applicants and licensees. A PRA has been submitted to NRC by Pt.blic Service Company of New Hampshire, an operating license applicant, pcetainir.g tc the Seabrook Nuclear Power Plant C"-+
OBJECTIVE g ,,g,,./.ey The objective of the present task is t review those aspects of the Seacra.
PRA leading to the estimates of risk .fs plant damage state to detereine the accuracy of the estimates.
WORK REQUIREMENTS Perform a comprehensive, quantitative review and evaluation of the risk assess-ment being submitted by the licensee for tte Seabrook PWR power plant te deter-mine if the estimates of risk reflect appropriate use of risk assessment m thocs and plant / site information.
The defensibility of the licensae's submittal of the risk and the a>>vciated uncertainty spread with respect to (1) use of state-of-the-art rist assessment 05/24/84 4 LETTER TO OGEkA W ENCLOSURES
s methods, (2) thoroughness and comprehensiveness of analysis, (3) availability and appropriate use of data, and (4) realism of modeling assumptions will be evaluated. The impact of deficiencies or understated uncertainties in the licensee's analysis of sequences will be identified.
The review will cover all aspects of the study from the point of calculation of the frequencies of the plant damage states, including methodology, assumptions, data, information sources, models, plant understanding, completeness of the analysis, and any other area where inconsistencies may arise which could affect the quantitative or qualitative results. A sensitivity analysis will take alternatives identified in the review in appropriate combinations and determine the inc-emer.tal change in risk resulting fram the use of alternatives in the dorni na nt sequences corresponding to each clant damage state: In general, these alternatives should be evaluated by performing localized calculations within the analysis.
The work to be performed in accord with this Statement of Work is to be based in part upon the " front-end" work to be performed by the Lawrence Livermore National Laboratory under NRR/ DST funding (FIN No. A-3754-4), and is to be fully coordinated with that effort.
The work described herein consists of one task which is divided into several parts to be consistent with the A-3754-4 effort. These are:
- 1. Evaluation of Risk Due to Internal Events
- 2. Evaluation of Risk Due to External Events
- 3. Draft Final Reports 4 Final Reports
- 5. Questions to Licensee Each item is discussed below.
Contract Task: Perform "Back-end" evaluation of the Seabrook PRA.
-f \ ' Q Estimated level of effort: .L^ ' . . . r sm ff ' ]
F[ '
NW Estimated completion date: -Gert- 30, 1985 g, y 7 ) ,j . ,
,Wg 05/24/84 5 LEITER TO OGEKA W/ ENCLOSURES -
s The following items are to be accomplished to conplete the contract task:
(1) Evaluation of Risk Due to Internal Events (a) Review and evaluate the scope, assumptions, and systems analysis aspects of risk due to internal events. Include:
- 1. Station blackout (loss of offsite and emergency ac power) a) Reactor Coolant Pump (RCP) seal failure (af ter station blackout) b) loss o' cc af ter itt i te tin'e due te battery cepietier.
(after station blackcut), or immediate loss of DC ce:aase of prior undetectec cattery failure (after loss of offsite power).
- 2. Loss of dc power
- 3. Loss of instrument anc control power
- 4. Multiple instrument tube LOCA below core level
- 5. Overcooling events - (Pressurized thermal shock)
- 6. Steam generator tube fa' lure, including subsequent stuck-oper secondary side safety relief valve
- 7. ATWS
- 8. Stuck open S/R valve
- 9. Loss of main feedwater
- 10. Containment isolation failure
- 11. Turbine trip 05/24/84 6 LETTER TO OGEKA W/ ENCLOSURES
O s
- 12. Loss of component cooling water
- 13. Loss of service water
- 14. Loss of ventilation in auxiliary building
- 15. Pipe breaks in auxiliary building
- 16. Reactor coolant pump seal failure (as contribution to small LOCA initiator)
- 17. Baron dilutter
- 18. Excess feednater events, including their possible contributier to loss of main feedwater
- 19. Loss of instrument and control air and other items identified as a result of the initiating events review and provided to BNL by the NRC Program Manager.
(b) Develop a table of assumptions used in the analysis and make a finding on the validity.
(c) Identify all known omissions and deficiencies in the systems analysis and estimate the impact where possible. Include the technical basis for these estimates.
(d) Incorporate NRR technical review comments as provided by the NRC Program Manager.
(e) Assess the uncertainty analysis. Examine propagation and complete-ness in treatment of uncertainty, data uncertainty, and modeling ser-sitivity/ uncertainty.
05/24/84 1 LETTER TO OGEKA W/ENCLOSUtd5
- ?
\
(f) Maintain close contact with Lawrence Livermore National Laboratory in regard to the front-end analyses which serve as the starting point for the above work. *
/
(2) Evaluation of Risk Oue to External Events ,
(a) For each type of external event considered, concur with or modify -
the risk information for each plant damage state. ,
(b) Review and evaluate the implicit and explicit assumptions of the external events risk analysis. <
(c) Identify all known omissions and deficiencies in the external event risk analysis, and estimate the impact where possible. For those E omissions and deficiencies for which evaluation is believed to be beyond the state-of-the-art, provide a list and the basis for this I
belief.
(d) Assess the uncertainty analysis. Examine propagation and complete-ness in treatment of uncertainty, data uncertainty, and modeling sensitivity / uncertainty.
(e) Maintain close contact with Lawrence Livermore Laboratories in regard to the front end analyses which serve as the starting point for the iss (2
+
f & ~ ) work.
(3) Draft F4a41 Reports '
A Draf t F4.*1 Report is to be provided which covers the effort accomplished in FY84 and a second Oraf t F-twe4 Report is to be provided which covers the effort accomplished in this program. The reports are to include, at a minimum, the following:
(a) For each of the pRA areas, define the basis for acceptability and describe what was considered in the review.
05/24/84 8 LETTER TO OGEKA W/ ENCLOSURES
s '
c The findings will include reestimates, as appropriate, of risk infor-
-9 s
mation corresponding to each plant damage state,' identification of areas that were not pursued, and identification of grey areas where
' ', ' #~'
sensitivity studies might be used to bound a central estimate.
(b) Describe areas of incompleteness (all known omissions and deficien-cies) determined in the review. Quantify, where possible, the poten-tial impact of these areas. Discuss the basis for quantification values.
'(c) Based on reviewer audits, discuss the accuracy, uncertainty, and adequacy of the PRA author's risk avar.tifications.
4 (d) An approximate outline of the reports is given below:
, s
- 1. Summary i
, 2. Introduction s
2.1 Background
- 2.2 Scope i 2.3 Assumptions
- 3. Internal Events Risk i
- 4. External Events Risk
- 5. Summary and Conclusions
! 5.1 Dominant Risks Corresponding to Each Plant Damage State 5.2 Important Problems and Omissions 5.3 Treatment of Uncertainties 5.4 Overall Evaluation of Seabrook Risk Assessment
- 6. Appendices (as required) 05/24/84 9 LETTER TO OGEKA W/ ENCLOSURES
..--,-,:,--,,-..,,..-~,,.-,-,.-,--..n-,...,--a,.,,nnr,-- -_,--.r,,.~,,.. ,,--n--,.--,n.,. ,.,,,-,,--r- -
,----.-,,n,-,-
?
% y l
l This outline is similar to the outline to be followed by Lawrence Livermore l in their accomplishment of FIN A-3754-4. Although the BNL and Lawrence Livermore reports are to be " stand alone" reports, the contents are to be
, coordinated so that complete coverage of the technical topic is provided if one has both the BNL and the Lawrence Livermore reports.
/ * 'y '
! (4) Final Reports The final reports will take into account pertinent comments on the draft final reports by NRC and other interested parties. They will be publishec as NUREG/CR reports. The first final report is to be provided by November 30, 198 second, which covers the entire program, is to be provided by maca 30.1985.
,4 -'
(5) Questions to Licensee ,,e d 4 :,
s .
Provide questions for forwarding to the licensee covering all aspects of h the analysi s <e->+ 6 #:'eMI -
- M .4 " M "
/-c ,r);y/,cw h m y wo & fh h A % fA'/c J a l s LEVELOFEFFORTANDpERI'0DOFPERFORMANh 8SC r .
,y fy. V ON~y.u ,
The estim'ated level effort is.k et professional staff years with the effort to be completed by I% 30, 1985.
TECHNICAL REPORTING REQUIREMENTS:
All technical products which are required from this contract have been identi-fied specifically in the above discussion. BNL shall submit six copies of #
draft NUREG/CR reports to the NRC Project Manager, for staff review and appro-val. For NUREG/CR reports, within sixty days of receipt of the staff's comments on these reports, the contractor shall submit one (1) reproducible and six (6) reproduced copies of the final reports in accordance with NRC Manual Chapter 3:02' " Publication of Unclassified Regulatory and Technical Reports Prepared by NRC Contractors."
05/24/84 10 LETTER TO OGEKA W/ ENCLOSURES
\.
{f US. NUCLEAR REGULATORY COMMISSION DATEOFPROPCSA6 NnC F ORM 109 a sir / ,\ 6/5/84 g)~En
) PROJECT AND BUDGET PROPOSAL FOR NRC WORK O aEvisiO~ so FIN NLYBE R PROJECT TITLE REVIEW 0F SEABROOK NUCLEAR POWER PLANT PROBABILISTIC A0801 RISK ASSESSMENT NRCS&RNUYSER
"" 7f'iS of Nuclear Reactor Regulation / Division of Safety Technology 20-19-40-41-5
^U"^
DOE CONTRACTOR '"""
Lawrence LiverTnore National Laboratory DOE S&R NUMBER LiverTnore, California PERIOOOF PERFORMA.NCE ORGANIZATION FTS PHONE NUM8ER COGNIZANT PERSONNEL STARTING DATE NRC PROJECT MAN AGER 5/15/84 COMPLETION DATE
. OTHER NRC TECHNICAL STAFF S. M. Davis NRR/ DST 492-7546 1/15/85 s
OOE PROJECT MAN AGER g, W. Gallacher DOE / SAN 536-7916 6.
f CONTR ACTOR-PROJECT MAN AGER L. L. Cleland LLNL 532-4949 7 PRINCIPA L INVESTIG ATORIS) hk. ,
LLNL 543-3961 Wy ~
A. A. Garcia 543-4949 J. M. Johnson, Resource Manager LLNL fj FY FY STAFF YE ARS OF EFFORT (Round to warrst renr4 of s >cari FY 84 FY 85 iFY o.r ci Sci.nu.cn.cnn.c.' .7 .4 Oiner o.r.ct <Gr.o.d > ,) ,j
.8 .5 ! l TO1 AL olRECT STAFF YE ARS COST PROPOSAL o r.ct S.i.'** 42.8 30.8 Material and Services IE neluding ADP)
I AoP Support ;
j Subconir.c 120 20 .
- "* sc gg gg Indirect Labor Casts 41.2 29.6 .
Other (Specofy)
General and Administrative i l6 %) 34 18 i TOT AL OPE RATING COST 260 140 CAPITAL EQUIPMENT FIN CHARGED: N/A o 0 l
TOTAL PROJECT COST $260K $l40K e JANyAE' F[gE,AE- VA*.*
Chlh6kb NQW EV8k b lO6CIV0f A yy 4 MONTHLv F0atcAST .A A S* Ef 5'tV:
APA VAv JUNE gsvLv ,
EXPENSE 30 80 90 60 l l
~.c,0.o,,,
a .'> w- R M N7-w 6 1
\
l B/7 I
t
Project
Title:
Review of Seabrook Nuclear Power Plant FIN /189 No. A0801 Probabilistic Risk Assessment B&R No. 20-19,40-41-5 Wang No. 0473x/6-11-84 1.0 OBJECTIVE OF PROPOSED WORK
1.1 Background
The Office of Nuclear Reactor Regulation is conducting a probabilistic risk assessment (PRA) review program in which PRAs performed and submitted to the NRC by license applicants and licencees receive comprehensive review and evaluation. The program is the responsibility of the Reliability and Risk Assessment Branch (RRAB).
A PRA of the Seabrook Nuclear Power Plant (Seabrook PRA) has been submitted to the NRC by Public Service Company of New Hampshire, an operating license (OL) applicant. The review of this document, whose title is "Seabrook Station Probabilistic Safety Assessment," is being performed as one project in the larger NRC program.
1.2 Objective The object.ive of th.is_ project is to review those aspects of the Seabrcok PRA leading to the estimates of the frequencies of each plant damage state to determine the accuracy of these estimates. .
2.0
SUMMARY
OF PRIOR EFFORTS LLNL has been involved in PRA methods development and applications for the NRC for a number of years dating back to our involvement in the Reactor Safety Study. Current activities include a review of the Millstone 3 PRA for NRR/ DST; the development of a seismic risk assessment methodology for RES/DET in our Seismic Safety Margins Research Program (SSMRP), and a systems interaction methodology for NRR/ DST. Related PRA activitic are ongoing for 00E and FEMA projects.
3.0 WORK TO BE PERFORMED AND EXPECTED RESULTS Perform a comprehensive review and evaluation of the qualitative and quantitative aspects of the risk assessment being submitted by the licensee for the Seabrook PWR power plant to determine if the estimates of the frequencies of the plant damage states reflect appropriate use of risk assessment methods, plant / site information, and reliability data.
e
E Projec:
Title:
Review of Seabrook Nuclear Power Plant FIN /189 No. A0801 Probabilistic Risk Assessment B&R No. 20-19-40-41-5 Wano No. 0473x/6-il-84 The defensibility of the licensee's submittal of the frequencies of plant damage states and the associated uncertainty spread with respect to (1) use of state-of-the-art risk assessment methods, (2) thoroughness and comprehensiveness of analysis, (3) availability and appropriate use of data, and (4) realism of modeling assumptions will be evaluated. The impact of deficiencies of understated uncertainties in the licensee's analysis of sequences will be described and discussed.
The review will cover all aspects of the study up to the point of the calculation of the frequencies of the plant damage states, including metnodology, assumptions, data, information sources, models,' plant unaerstanding, completeness of the analysis, and any other area where inconsistencies may arise which could affect the quantitative or qualitative results. Alternatives identified in the review will be consioered in appropriate combinations to oetermine the incremental change resulting from the use of. alter.nativ_es jn.the dominant sequences corresponding to each plant oamage state. In general, these alternatives will be evaluated by performing localized calculations within the analysis. For example, minor inconsisten-cies ioentified in the event trees will be reevaluated to determine how alternative approaches would impact the sequence probabilities. An approximation of the impact of identified major errors or inconsistencies will be made; however, extensive requantification of event tree accident sequences are not within the scope of this project. Should such grave errors or inconsistencies be identified, the LLNL project manager will consult with the NRC project manager to determine the appropriate action to be taken.
The schedule for completion of the PRA review and delivery of a draft final report has been established at five months, with the final report due at eight months. The project start date has been established, as indicated on Page 1 (NRC Form 189).
Tne projected short schedule and relatively small budget for this review is predicated on several critical assumptions, principally concernec with access 4
, Project
Title:
Review of Seabrook Nuclear Power Plant FIN /189 No. A0801 Probabilistic Risk Assessment BM No. 20-19-40-41-5 Wang No. 0473x/6-il-84 to information requirements an6 the overall scope of our review. We have specifically made the following assumptions:
- a. Extensive accident sequence requantification requiring computer support is out of scope.
- b. Review of any consequence analysis included in the PRA is out of scope.
- c. Although identifying significant dependencies is a critical part of the review, performing a complete dependency analysis for front-line and support systems (at the train-to-train level) is out of scope.
Insufficient plant data will be available to the reviewers to perform such an analysis,
- d. 'LLNL' Eill have contact with a designated individual (a senior level representative) from the engineering staff of the plant or utility, and access to the plant site, exclusively coordinated (at least initially) by the designated individual and the NRC project manager. Site visits and requests for information by subcontractors / consultants will be coordinated by LLNL to coincide with similar LLNL visits and requests for information in order to minimize the buroen placed on the utility.
- e. Our review will be based on the NRC material listed in Section 12 l
herein and any additional information supplied by the NRC or licensee to support this review.
l The tasks to be performed are described below.
Task 1 Internal Events Evaluation (a) Review and evaluate the scope, assumptions, and systems analysis for internal events. Review for completeness the initiating events in the Project
Title:
Review of Seabrook Nuclear Power Plant FIN /189 No. A0801 Probabilistic Risk Assessment B&R No. 20-19-40-41-5 Wang No. 0473x/6-11-84 PRA including both the following events and combinations of initiating events with subsequent failures:
- 1. Station blackout (loss of offsite and emergency AC power) a) Reactor Coolant Pump (RCP) seal f ailure (af ter station blackout).
b) Loss of DC after finite time, due to battery depletion (af ter station blackout), or imediate loss of DC because of prior undetected battery f ailure (af ter loss of offsite power).
- 2. Loss of DC power
- 3. Loss of instrument and control power.
- 4. Multiple instrument tube LOCA below core level.
- 5. Overcooling events - (Pressurized thermal shock).
- 6. Steam generator tube f ailure, including subsequent stuck-open secondary side safety relief valve
- 7. ATWS
- 8. Stuck open S/R valve.
- 9. Loss of main feeawater.
- 10. Containment isolation failure.
- 11. Turbine trip.
- 12. Loss of component cooling water.
- 13. Loss of service water.
14 Loss of. ventilation in auxiliary building.
l 15. Pipe breaks in auxiliary building.
l 16. Reactor Coolant Pump seal f ailure (as contribution to small LOCA J initiator).
! 17. Boron dilution.
- 19. Loss of instrument and control air.
l Assess the completeness and treatment of transients /LOCA initiating events which also degrade mitigating systems.
. Project
Title:
Review of Seabrook Nuclear Power Plant FIN /189 No. A0801 Probabilistic Risk Assessment B&R No. 20-19-40-41-5 Wang No. 0473x/6-il-84 (b) Develop a table of assumptions used in the analysis and make a finding on their validity. These assumptions include such considerations as pump operabilities with insufficient cooling or net positive suction pressure, operability of components in degraded environments, minimum components needed to sustain a function, and availability of equipment based on technical specifications.
(c) Review the event trees for completeness and validity, and identify all functional and support system interdependencies that were considered or should be considered in the evaluation. This should include coupling with the initiating event. Evaluate the significance of areas which are incomplete. Review the stated and implicit assumptions associated with success paths in the event trees (e.g., feed and bleed). Review the event tree logic, and assess the validity of assignment of CDmbinations of successes and f ailures of systems to the plant damage states (system success criteria). Consider system dependencies arising f rom interaction related to the physical phenomena; icentify and evaluate any omissions.
Compare system success criteria to those used in other PRAs for similar systems under similar circumstances. Assess the validity of the treatment of transient-induced loss of coolant accidents, and other such transfers from one type of event tree to another.
(d) Review the f ault trees to determine their accuracy, validity, and completeness in quantifying the high risk sequences. The subjects listeo below are of particular interest.
o definition of the top events in fault trees, o test and maintenance unavailabilitiet, o consistency of f ault trees with system success criteria, o common cause interactions, o human errors (cognitive, procedural, latent, dynamic) o design errors, o consequential f ailures (coupled to initiating event),
o f ailure rate data and uncertainties, o completeness of fault trees.
l l
l
. Project
Title:
Review of Seabrook Nuclear Power Plant FIN /189 No. A0801 Probabilistic Risk Assessment B&R No. 20-19-40-41-5 Wang No. 0473x/6-ll-84 i
Review and evaluate the dependency analysis performed in the PRA. The PRA should include an analysis, on a train-to-train basis, for the dependency of front-line systems on support systems, and the dependency of support systems on other support systems. If this analysis is not provided, or is incomplete, use available information to perform a limited dependency analysis on a train-to-train basis - e.g., which trains of a given front-line system depend on which trains of a support system. Display the results in the form of a dependency table or diagram. Identify and evaluate the impact of any omissions in the PRA.
(e) Determine whether the limit of resolution in the fault tree analysis is acequate for the identification of common mode f ailures. Determine the adequacy of the identification and qualitative analysis of common mode failures and systems interactions including the treatment of common mode
^
f ailures arising from hard-wired coupling, spatial / environmental coupling, 'coupl'ed human errors, design errors and inadequate testing resulting in the f ailure to recognize that a system may respond successfully during a test but not during a true demand. Develop a table of connon cause considerations and compare quantification in this PRA with previous PRAs.
(f) Assess the completeness, accuracy, and adequacy of the conditional probabilities for some system's success /f ailure given another system's previous success / failure.
(g) Determine the sources of data used for quantification of the f ault trees, and compare them to data sources used in other PRAs. Highlight data used in quantifying trees if the data deviate significantly from data previously used in other PRAs. Particular interest should be accorded recovery or repair rates and failure rates. Examine the validity of the method of combining generic data with plant specific data.
Project
Title:
Review of Seabrook Nuclear Power Plant Flh/189 No. A0801 Probabilistic Risk Assessment ,
B&R No. 20-19-40-41-5 Wang No. 0473x/6-11-84 (h) Identify all known omissions and deficiencies in the systems analysis including support system dependencies and estimate the impact where possible. Include the technical basis for these estimates. For those l omissions and deficiencies for which evaluation is believed to be beyond the state-of-the-art, provide a list and the basis for this belief.
(i) Incorporate NRR technical review comments as provided (success / failure criteria, environmental qualifications, etc.).
(j) Review the following issues and discuss their applicability to Seabrook.
O how NUREG/CR-2497, " Precursors to Potential Severe Core Damage Accidents: 1969-1979, A status Report" relates to the plant and its risk analysis, o how the recent failure of scram breakers to operate satisfactorily at the Salem plant relates to Seabrook and its risk analysis, o the conditional probability that " containment fails to isolate on demand" (provide a basis for this value).
l (k) Assess the validity of the treatment of human errors, both those occurring after an accident (dynamic) and prior to an accident (latent, e.g., test and maintenance errors). Assess the completeness and treatment of cognitive errors. Develop a human error table of significant actions showing time frame for action, availability of f
procedures and HEP, and compare with HEP from other PRAs.
(1) Assess the analytical modeling and quantification of accident sequences. -
l t
(m) Review the sequence frequency calculations corresponding to each plant l
damage state to ascertain accuracy, uncertainty, completeness, and acequacy. Where the reviewers disagree with the PRA in a significant way l
, -- - - , - , - , , - ,, y m- - - r-, --
. Project
Title:
Review of Seabrook Naclear Power Plant rlh/is9 ho. A065i Probabilistic Risk Assessnent B&R No. 20-19-40-41-5 Wang No. 0473x/6-11-84 (e.g., assumptions, f ailure rates, success criteria, omissions), the reviewers will reevaluate the sequence frequencies by performing localized calculations within the analysis to determine how alternative approaches would impact the sequence probabilities.
(n) Compare the dominant sequences corresponding to each plant damage state to existing PWR PRAs, generic data, and operating experience to help assure that no significant sequences are omitted.
(o) Assess the uncertainty analysis. Examine propagation and completeness in treatment of uncertainty, data uncertainty, and modeling sensitivity / uncertainty.
Task 2 External Events Evaluation (a) For each type of external event consioered, concur with or modify the estimated hazard curves, assess the completeness of the sequences considered for each plant damage state, assess the treatment of common cause interactions and human errors, and evaluate the fragility or failure estimates of the components identified by the appropriate event /f ault trees.
(b) Review the event and fault trees to determine their accuracy, validity, and completeness for external events. Review and evaluate the implicit and explicit assumptions of the external events analysis.
(c) Identify all known omissions and deficiencies in the external event analysis, and estimate the impact where possible. For those omissions and deficiencies for which evaluation is believed to be beyond the state-of-the-art, provice a list and the basis for this belief.
(d) Review the sequence frequency calculations corresponding to each plant damage state to ascertain accuracy, uncertainty, completeness, and adequacy. Where the reviewers disagree with the PRA in a significant way
, (e.g., assumptions, f ailure rates, success criteria, omissions), the
. Project
Title:
Review of Seabrook Nuclear Power Plant FIN /189 No. A0801 Probabilistic Risk Assessment B&R No. 20-19-40-41-5 Wang No. 0473x/6-ll-84 reviewers will reevaluate the sequence frequencies by performing localized calculations within the analysis to determine how alternative approaches would impact the sequence probabilities.
(e) Assess the uncertainty analysis. Examine propagation and completeness in treatment of uncertainty, data uncertainty, and modeling sensitivity / uncertainty.
Task 3 Draf t Final Report on Tasks 1 and 2 (a) For each of the PRA areas (e.g., initiating events, initiating event frequencies, component f ailure rates, common cause f ailures, human reliability analysis, test and maintenance, event trees, f ault trees, success /f ailure criteria, external events, quantification, and uncertainties) determine if the analysis reflects appropriate use of risk assessment methods, plant / site information, and reliability data; define the basis for the finding and describe what was considered in the review.
The finding will include reestimates, as appropriate, of the dominant sequence frequencies corresponding to each plant damage state, ioentification of areas that were not pursued and ioentification of grey areas where sensitivity studies might be used to bound a central estimate.
(b) Describe areas of incompleteness (all known omissions and deficiencies) determined in the review. Quantify, where possible, the potential impact of these areas. Discuss the basis for quantification values.
(c) Based on the review of sequence calculations, discuss the accuracy, uncertainty, and adequacy of the PRA author's sequence quantifications.
(d) An approximate outline of the report is given here.
C
- Project
Title:
Review of Seabrook Nuclear Power Plant FIN /189 No. A0801 Probabilistic Risk Assessment B&R No. 20-19-40-41-5 Wang No. 0473x/6-il-84
- 1. Executive Susnary
- 2. Introduction
2.1 Background
2.2 Scope 2.3 Assumptions 2.4 Swanary of Results and Insights Presented in the PRA
- 3. Internal Events Analysis 3.1 Initiating Events 3.2 Event Trees LOCA Transient Other 3.3 Success Criteria 3.4 Systems Descriptions Fault Tree Models 3.5 Human Factors 3.6 Failure Data 3.7 Operating Experience Analysis 3.8 Analysis Codes 3.9 Accident Sequences 3.10 Dependencies 3.11 Quantification 4 External Event Analysis 4.1 Seismic 4.2 Fire 4.3 Industrial Accidents 4.4 Other l
. Project
Title:
Review of Seabrook Nuclear Power Plant FIN /189 No. A0801 Probabilistic Risk Assessnent B&R No. 20-19-40-41-5 Wang No. 0473x/6-11-84
- 5. Summary and Conclusions 5.1 Dominant Sequences Corresponding to Each Plant Damage State 5.2 Important Problems and Omissions 5.3 Treatment of Uncertainties 5.4 Overall Evaluation of Seabrook Risk Assessment
- 6. Appendices (as required)
Task 4 Final Report The final report will take into account pertinent comments on the draft final i report by NRC and other interested parties. It will be published as a NUREG/CR.
This task assumes that the NRC will respond within the 45 calendar days allowed for coinents inl.'he project schedule. Delay beyond this time will
, necessarily delay completion of the final report on a day-for-day basis.
i Task 5 Questions to Licensee i
Proviae questions for forwarding to the licensee covering significant all i
aspects of the systems analysis. (Responses already may have been received informally).
- 4. DESCRIPTION OF ANY FOLLOW-ON EFFORTS None.
- 5. RELATIONSHIP TO OTHER PROJECTS LLNL has developed and applied probabilistic risk assessment technology on the Reactor Safety Study, the Seismic Safety Margins Research Program (SSMRP), and various systems interaction studies for NRR. Information from the SSMRP will be used in the evaluation of the component fragility or failure estimates. In addition, information developed as a result of work done on the seismic Hazard l Characterization of the Eastern U.S. will be used, as appropriate, in the l
l !
- .- - , , --. - -.,.,,,~ .
Project
Title:
Review of Seabrook Nuclear Power Plant FIN /189 No. A0801 Probabilistic Risk Assessnent B&R No. 20-19-40-41-5 War.g No. 0473x/6-il-84 external event evaluation of the seismic hazard curve for the plant site.
Some information from a DOE program to assess natural hazards at a number of DOE sites may be used. !
- 6. REPORTING REOUIREMENTS 6.1 Technical Reports Upon completion of Task 3, LLNL will formally submit a draft final report ]
covering Tasks 1, 2, and 3 as defined in Task 3. Upon completion of Task 4, l LLNL will submit the final report which takes into account industry and NRC comments. Upon completion of Task 5, LLNL will submit questions for forwarding to the licensee.
6.2 Business Letter Report A monthly business letter will be submittec at the end of each month of effort to the Project Manager with copies to the Director, Division of Safety Technology, ATTN: J. Halvorsen; A. Thacani, DST; F. Rowsome, DST; R. Frahm, DST; and L. Solander, NRR. These reports will identify the title of the project, the FIN, the Principal Investigator, the period of performance, and the reporting period and will contain 3 sections as follows:
Project Status Section
- i. A listing of the efforts completed during the pericd; milestones reached, or if missed, an explanation provided.
ii. Any problems or delays encounterea or anticipated and recommendations for resolution. 1/
1/ If the recomended resolution involves a contract modification, i.e.,
change in work requirements, ievel of effort (costs), or period of performance, a separate letter should be prepare,c and submitted to the Director, Division of Safety Technology, ATTN: J. Halvorsen anc a copy provided to the NRR Project Manager and L. Solander, NRR.
1
Project
Title:
Review of Seabrook Nuclear Power Plant FIN /189 No. A0801 Probabilistic Risk Assessment B&R No. 20-19-40-41-5 Wang No. 0473x/6-il-64 iii. A summary of progress to date (this may be expressed in terms of percentage completion for the project).
iv. Plans for the next reporting period.
Financial Status Section
- i. Provide the total cost (value) of the project as reflected in the proposal (NRC Form 189), the total amount of funds obligateo to date, the balance of funds required to complete the work by fiscal year, and a summary of costs as shown in Attachment A.
ii. Provide the estimated total amount of funds expended (costed) during the period prior to the report period and cumulative to date (see Attachment A).
Fee Recovery Cast Status Section Pursuant to the provisions of NRC Regulations,10 CFR 170, provice the total amount of funds expenced (Costed) during the period and cumulative to date and report them on a_ separate page as part of this report in the format shown in the second page of Attacnment A:
- 7. SUBCONTRACTS, CONSULTANTS AND/0R MATERI ALS We anticipate the use of subcontractors and consultants to assist in this work. The two subcontractors and one consultant listed below have already been specifically identified, others may also be used.
- a. Subcontractors -
(1) Applied Risk Technology Corporation (ARTECH); P. J. Amico (2) Jack R Benjamin and Associates, Inc. (JBA); J. W. Reed, M. W. McCann, Jr.
- b. Consultants (1) P. R. Davis a
l Project
Title:
Review of Seabrook huclear Power Plant FIN /189 No. A0801 i
Probabilistic Risk Assessment B&R No. 20-19-40-41-5 Wang No. 0473x/6-11-84
- 8. LIST NEW CAPITAL EQUIPMENT REQUIRED q
Not Applicable.
- 9. DESCRIBE SPECIAL FACILITIES REQUIRED Not Applicable.
- 10. CONFLICT OF INTEREST INFORMATION No known conflicts or apparent conflicts of interest.
- 11. MEETINGS AND TRAVEL o Contractor may attend a 2-day visit at an unspecified site with the licensee to discuss questions on his analysis and may attend six l-day meetings at NRC heaoquarters in Washington, D.C. for four participants.
o Four individuals may conduct two three-day visits to the Seabrook site to look for potential common cause vulnerabilities, review of control operations, and a general overview of the plant layout and potential idiosyncrascies.
- 12. NRC FURNISHED MATERIALS The NRC staff will furnish LLNL with copies of the following documents:
- 1. The Probabilistic Risk Assessment (PRA) ii. The plant's Final Safety Analysis Report (FSAR) iii. The question and answer volumes of the FSAR, if applicable iv. A set of P&ID's for the plant Other material may be requested as required.
- 13. PROPRIETARY DATA l
In the event any proprietary information is submitted by the NRC in connection with this project, it must be specifically identified. The University agrees to exercise its best efforts to protect such proprietary data. Furthermore, 1
Project
Title:
Review of Seabrook Nuclear Power Plant FIN /189 No. A0801 Probabilistic Risk Assessment B&R No. 20-19-40-41-5 Wang No. 0473x/6-il-84 limitation shall not be imposed on the use of any information and data previously delivered to the University or government without limitations or previously published in any form as to be generally available.
- 14. PATENT STATUS Not Applicable.
- 15. TASK "X" Oh-CALL ASSISTANCE
- Not Applicable.
- 16. SUMMARIZE DELIVERABLES At the completion of the project a final report will be submitted summarizing all project work and results.
e N
1 1
1
_. , _ _ _ _ _ _ _ ,_ , _ _ _ _. .~ - _ _ _ _ _ _ _ _ _ _ _ __ . _ _ - -_-- - --
ATTACHMENT A MONTHLY PROJECT FINANCIAL STATUS (Month)
Review of the Seabrook Probabilistic Risk Assessment FIN-A0801 A. PROJECT COSTS:
Total Projected Funds Obligated Balance of Funds Project Cost to Date by Fiscal Year FY84 FY85 K $ K $ K $ K B. COST ANALYSIS
- Period Cumulative Direct Lab Staff Effort - FTE i Direct Salaries $ K $ K Materials & Services ADP Support - -
Subcontracts Travel Expenses Indirect Labor Costs Other (TID)
General & Administrative Total Expenses 5 K $ K Liens K
Total Costs ano Liens 5
( %) of funding available
- Note: These figures are for cost analysis only and may differ slightly from ..
final billing figures.
- , . , - . . . , - - - - , - - - - - . ~ - - - - , _ . , - . - , - - - - - - , - - - - - . - . . , -
- + - .-- , ,- .. - -.
ATTACHMENT A (continued)
C. FEE RECOVERY COST STATUS FIN: A0801 TITLE: Review of the Probabilistic Risk Assessment for the Seabrook Nuclear Power Plant PERIOD: (Month)
Docket Costs Facility Name Number Period Cumulative Seabrook 50-443 $ K $ K Common Costs 2/ 50-900 Total Expenses ! K $ K i 2/ Common costs are for those costs incurred for effort such as preparatory or start-up efforts to interpret and reach agreement on methodology, approach, acceptance criteria, regulatory position, or TER f ormat; efforts associatec with the lead plant" concept that might be involveo during the first one or two plant reviews as estimated by the contractor; meetings / discussion involving the above efforts to provide orientation, background knowledge, or guidance at the beginning cr during performance of work; and any technical effort applied to a category of f acilities, e.g., reactor analyses on all BWR facilities. In the case of the latter example, these costs should be prorated equally to only those facilities to which the ef fort applies.
Development of methodologies, criteria, or technical positions are not fee-recoverable and, therefore, should not be categorized as common costs.
Management and related support costs chargeable directly to the effort are not to be reported as common costs and should, therefore, be charged in proportion to the other direct costs associated with those f acilities during the reporting period.
NOTE: Conrnon costs are to be accrued on a monthly basis and prorated equally among the f acilities identified under the effort at the end of each fiscal year or at the completion of the effort, whichever occurs first, l
O A.
Lawrence Livermore National Laborato .
NUCLEAR SYSTEMS SAFETY PROGRAM June 19, 1984 NSSP 84-1162 Ms. Sarah M. Davis Reliability and Risk Assessment Branch Division of Safety Technology U.S. Nuclear Regulatory Commission Washington, D.C. 20555
Dear Ms. Davis:
Attached please find Final 189 proposal:
FIN A0801 " Review of Seabrook PRA".
This proposal is now in process for formal approval by LLNL management.
Sincerely,
,p - dA<~J -r, NckM. Johnson,ResourceManager Nuclear Systems Safety Program l
i Attachment 1
i cc: L. L. Cleland/G. E. Cummings A. A. Garcia J. Stuart 1
pc3 /1 - i 7-o c' G B/y.
O,#1<- n s / ~1 fish
^ O J(pWS . VII \f/
l
' l L .- . . . ..
V Eq..a Qw:.n . Enn er
- L?w s ', O'Cr'na
- PO Ba %5 veme Ceucma MSS: . Te:e.y<yu rts :21133 7s , V:
u.S.NuCtEAR nEGvLATO.=v COvwssiOs caTEo.*RosesA6 Nr.C FoxM ses
,f 6/5/84 om .
g ,, E ,
e i j PROJECT AND BUDGET PROPOSAL FOR NRC WORK O REvisies Nc FIN NUMBE R PROJE CT TsTLE REVIEW 0F SEABROOK NUCLEAR POWER PLANT PROBABILISTIC A0801 -
RISK ASSESSMENT NRC B&R NUMBE R
""Ni$e of Nuclear Reactor Regulation / Division of Safety Technology 20-19-40-41-5 COhl h AGION ACCOUNT DOE CONTR ACTOR ~
Lawrence Livermore National Laboratory l doe S&R NUMBER slTE l
Livermore, California PE RIODOF PE RF ORMANCE ORGANIZATION FTS PHONE NvMBER COGNf ZANT PE RSONNEL STARTING DATE NRC PROJECT MANAGE.R ,_ _
5/15/84 COMPLETION DATE OTHER NRC TECHNICAL STAFF 1/15/85 NRR/ DST 492-7546 S. M. Davis Ag.
h9~@ %.
OOE PROJECT M AN AGER DOE / SAN 536-7916 W. Gallacher CONTRACTOR-PROJECT M AN AGER LLNL 532-4949 % -
L. L. Cleland '
- PRINCIP AL INVESTIG ATORtS)
A. A. Garcia
~
LLNL LLNL 543-3961 543-4949 , .
jg._ a J. M. Johnson, Resource Manager M6mW t
IFY STAF F YE ARS OF E F FORT (Aosend to acerest senen ef e .warf (FY 84 ,
FY 85 IFY lFY O ecise am.ct' cna.a' .7 .4 Ovnee Direc* 4Graoed)
,} ,]
TOTAL DIRECT STAFF YE ARS l .8 .5 f l J
f COST PROPOSAL O eci se+.n _ . 42,8 _ 30.8 ..
Maier al sad Serv.ces (E acauding ADP)
ADP Support soixmair.eu 120 20
' - ' < - C'".. 32 9.E lad.,,ci L.t=, Con.
41.2 29.6 <
~
'"" "*"" ( T I D) 32 ceaer.i .ad Aa .nr...= ( l5 s1 34 18 TOT AL OPE RATING COST 260 140 CAPITAL EQUIPMENT I FIN CH ARGED: N/A 0 0 )
TOTAt raOJECT Cost 5260K $140K ca o n e., . ovio.6 .
oecty.i s su , ...u.., ..u
,, g4 Mo.eT tysontcast
~
MA' JUN[ JVtY AUGy$T $(ei t w e t s.
LI Pg ., $( A P Ali
- -- 30 80 90 60 Nae r oa i >
(} Si)
$ fnO E ^ Y"> ff fg DMy"V - pga
Project
Title:
Review of Seabrook Nuclear Power Plant FIN /189 No. A0801
, Probabilistic Risk Assessment B&R No. 20-19-40-41-5 Wang No. 0473x/6-il-84 1.0 OBJECTIVE OF PROPOSED WORK
1.1 Background
The Office of Nuclear Reactor Regulation is conducting a probabilistic risk assessment (PRA) review program in which PRAs performed and submitted to the NRC by license applicants and licencees receive comprehensive review ano evaluation. The program is the responsibility of the Reliability and Risk Assessment Branch (RRAB).
A PRA of the Seabrook Nuclear Power Plant (Seabrook PRA) has been submittea to the NRC by Public Service Company of New Hampshire, an operating license (OL) applicant. The review of this document, whose title is "Seabrook Station Probabilistic Safety Assessment," is being performed as one project in the larger NRC program.
1.2 Objective The object.ive of, this_ project is to review those aspects of the Seabrook PRA leading to the estimates of the frequencies of each plant damage state to determine tne accuracy of these estimates.
2.0 S'JMMARY OF PRIOR EFFORTS LLNL has been involved in PRA methods development and applications for the NRC for a number of years dating back to our involvement in the Reactor Safety Study. Current activities include a review of the Millstone 3 PRA for NRR/ DST; the oevelopment of a seismic risk assessment methodology for RES/DET in our Seismic Safety Margins Research Program (SSMRP), and a systems interaction methodology for NRR/ DST. Related PRA activities are ongoing for DOE and FEMA projects.
3.0 WORK TO BE PERFORMED AND EXPECTED RESULTS Perform a comprehensive review and evaluation of the qualitative and quantitative aspects of the risk assessment being submitted by the licensee for the Seabrook PWR power plant to determine if the estimates of the frequencies of the plant damage states reflect appropriate use of risk assessment methods, plant / site information, and reliability data.
Project
Title:
Review of Seabrook Nuclear Power Plant FIN /189 No. A0801 Probabilistic Risk Assessment B&R No. 20-19-40-41-5 Wano No. 0473x/6-11-84 The defensibility of the licensee's submittal of the frequencies of plant damage states and the associated uncertainty spread with respect to (1) use of state-of-the-art risk assessment methods, (2) thoroughness and >
comprehensiveness of analysis, (3) availability and appropriate use of data, and (4) realism of modeling assumptions will be evaluated. Tne impact of deficiencies of understated uncertainties in the licensee's analysis of sequences will be described and discussed.
The review will cover all aspects of the study up to the point of the calculation of the frequencies of the plant damage states, including methodology, assumptions, data, information sources, models, plant understanding, completeness of the analysis, and any other area where inconsistencies may arise which could affect the quantitative or qualitative results. Alternatives identified in the review will be consioered in appropriate combinations to cetermine the incremental change resulting from the use of alter,ngtives jD the dominant sequences Corresponding to each plant damage state. In general, these alternatives will be evaluated by performing localized calculations within the analysis. For example, minor inconsisten-cies identified in the event trees wil,1 be reevaluated to determine how alternative approaches would impact the sequence probabilities. An approximation of the impact of identified major errors or inconsistencies will be made; however, extensive requantification of event tree accident sequences are not within the scope of this project. Should such grave errors or .
inconsistencies be identified, the LLNL project manager will consult with the NRC project manager to determine the appropriate action to be taken.
The schedule for completion of the PRA review and delivery of a draft final report has been established at five months, with the final report due at eight months. The project start date has been established, as indicated on Page 1
! (NRC Form 189).
Tne projected short schedule and relatively small budget for this review is predicated on several critical assumptions, principally concerned with access l
i 4
Project
Title:
Review of Seabrook Nuclear Power Plant FIN /189 No. A0801 i Probabilistic Risk Assessment B&R No. 20-19-40-41-5 Wang No. 0473x/6-ll-84 to information requirements and the overall scope of our review. We have specifically made the following assumptions:
- a. Extensive accident sequence requentification requiring computer support is out of scope. '
f
- b. Review of any consequence analysis included in the PRA is out of I
scope.
I
- c. Although identifying significant dependencies is a critical part of the review, performing a complete dependency analysis for front-line ano support systems (at the train-to-train level) is out of scope.
Insufficient plant data will be available to the reviewers to perform such an analysis.
- d. LLNL will have contact with a designated individual (a senior level representative) from the engineering staff of the plant or utility,
! and access to the plant site, exclusively coordinated (at least i
initially) by the designated individual and the NRC project manager. Site visits and requests for information by 4
subcontractors / consultants will be coordinated by LLNL to coincide with similar LLNL visits and requests f or information in order to minimize the buraen placed on the utility.
J
- e. Our review will be based on the NRC material listed in Section 12 f herein and any additional information supplied by the NRC or l licensee to support this review.
I
! The tasks to be performed are described below.
l Task I Internal Events Evaluation
- l (a) Review and evaluate the scope, assumptions, and systems analysis for
{ internal events. Review for completeness the initiating events in the -
i l ,
, , . . - .- ~~,_ . , . . . _ , , ,,, , _ . - , . . , - - . , _ . _ , _ , , , . - , , , _ . , , _ _ , , - . , .
, m-,m,-_.m..,m ., - ., _ - , ,
Project
Title:
Review of Seabrook Nuclear Power Plant FIN /189 No. A0801 Probabilistic Risk Assessment B&R No. 20-19-40-41-5 Wang No. 0473x/6-il-84 PRA including toth the following events and combinations of initiating events with subsequent failures:
- 1. Station blackout (loss of offsite and emergency AC power) a) Reactor Coolant Pump (RCP) seal f ailure (af ter station blackout).
b) Loss of DC af ter finite time, due to battery depletion (after station blackout), or immediate loss of DC because of prior undetected battery failure (af ter loss of offsite power).
- 2. Loss of DC power
- 3. Loss of instrument and control power.
- 4. Multiple instrument tube LOCA below core level.
- 5. Overcooling events - (Pressurized thermal shock).
- 6. Steam generator tube f ailure, including subsequent stuck-open secondary side safety relief valve
'. ATWS
- 8. Stuck open S/R valve.
- 9. Loss of main feedwater.
- 10. Containment isolation f ailure.
- 11. Turbine trip.
- 12. Loss of component cooling water.
- 13. Loss of service water.
- 14. Loss of ventilation in auxiliary building.
- 15. Pipe breaks in auxiliary building.
- 16. Reactor Coolant Pump , seal f ailure (as contribution to small LOCA initiator).
- 17. Boron dilution.
- 19. Loss of instrument and control air.
Assess the completeness and treatment of transients /LOCA initiating events which also degrade mitigating systems.
,e - Project
Title:
Review of Seabrook Nuclear Power Plant FIN /189 No. A0801 i Probabilistic Risk Assessment B&R No. 20-19-40-41-5 Wang No. 0473x/6-Il-84 1
(b) Develop a table of assumptions used in the analysis and make a finding on their validity. These assumptions include such considerations as pump operabilities with insufficient cooling or net positive suction pressure, j operability of components in degraded environments, minimum components i
needed to sustain a function, and availability of equipment based on technical specifications.
l (c) Review the event trees for completeness and validity, and identify all
- functional and support system interdependencies that were considered or should be considered in the evaluation. This should include coupling l with the initiating event. Evaluate the significance of areas which are incomplete. Review the stated and implicit assumptions associated with success paths in the event trees (e.g., feed and bleed). Review the i event tree logic, and assess the validity of assignment of combinations
- of successes and f ailures of systems to the plant damace states (system J
success criteria). Consider system dependencies arising from interaction i related to the physical phenomena; identify and evaluate any omissions, i Compare system success criteria to those used in other PRAs for similar ,
systems under similar circumstances. Assess the validity of the l treatment of transient-induced loss of coolant accidents, and other such
! transfers from one type of event tree to another.
- (d) Review the f ault trees to determine their accuracy, validity, and completeness in quantifying the high risk sequences. The subjects listed below are of particular interest.
o definition of the top events in f ault trees,
{ o test and maintenance unavailabilities, o consistency of fault trees with system success criteria, o common cause interactions, i
o human errors (cognitive, procedural, latent, dynamic) o design errors, f o consequential failures (coupled to initiating event),
o failure rate data and uncertainties, o completeness of f ault trees.
1, 3
l
-- ,-,ev 44,,,-a-----+-n---w-,,-am-.v,w-,,<--ve ,------s--,-nem,,--- .m, --,,--,,,w, ae,,.,,., ., w-,,, -,m - - - -
,e --w . , , , , , ,w.,me,.,,,v. m-,
Project
Title:
Review of Seabrook Nuclear Power Plant FIN /189 No. A0801 Probabilistic Risk Assessment B&R No. 20-19-40-41-5 Wang No. 0473x/6-11-84 Review and evaluate the dependency analysis performed in the PRA. The PRA should include an analysis, on a train-to-train basis, for the dependency of front-line systems on support systems, and the dependency of support systems on other support systems. If this analysis is not provided, or is incomplete, use available information to perform a limited dependency analysis on a train-to-train basis - e.g., which trains of a given front-line system depend on which trains of a support system. Display the results in the form of a dependency table or diagram. Identify and evaluate the impact of any omissions in the PRA.
(e) Determine whether the limit of resolution in the f ault tree analysis is acequate f or the identification of common mode f ailures. Determine the adequacy of the identification and qualitative analysis of common mode f ailures and systems interactions including the treatment of common moce f ailures arising from hard-wired coupling, spatial / environmental coupling, coupled hucar. errors, design errors and inadequate testing resulting in the f ailure to recognize that a system may respond successfully during a test but not during a true demand. Develop a table of common cause considerations and compare quantification in this PRA with previous PRAs.
(f) Assess the completeness, accuracy, and adequacy of the conditional probabilities for some system's success /f ailure given another system's previous success / failure.
I (g) Determine the sources of data used for quantification of the f ault trees, and compare them to data sources used in other PRAs. Highlight data used in quantifying trees if the data deviate significantly from data previously used in other PRAs. Particular interest should be accorded recovery or repair rates and failure rates. Examine the validity of the i
method of combining generic data with plant specific data.
l I
Project
Title:
Review of Seabrook Nuclear Power Plant FIN /189 No. A0801 Probabilistic Risk Assessment B&R No. 20-19-40-41-5 Wang No. 0473x/6-il-84 (h) Identify all known omissions and deficiencies in the systems analysis including support system dependencies and estimate the impact where possible. Include the technical basis for these estimates. For those omissions and deficiencies for which evaluation is believed to be beyond t the state-of-the-art, provide a list and the basis for this belief.
' . (i) Incorporate NRR technical review comments as provided (success /f ailure criteria, environmental qualifications, etc.).
(j) Review the following issues and discuss their applicability to Seabrook.
. o how N'JREG/CR-2497, " Precursors to Potential Severe Core Damage
- Accidents: 1969-1979, A status Report" relates to the plant and its risk analysis, 4.
o how the recen- f ailure of scram breakers to operate satisf actorily at the Salem plant relates to Seabrook and its risk analysis, o the conditional probability that " containment f ails to isolate on dernand" (provide a basis for this value).
(k) Assess the validity of the treatment of human errors, both those occurring af ter an accident (dynamic) and prior to an accident (latent, e.g., test and maintenance errors). Assess the completeness and treatment of cognitive errors. Develop a human error table of significant actions showing time frame for action, availability of '
procedures and HEP, and compare with HEP from other PRAs.
(1) Assess the analytical modeling and quantification of accident sequences.
(m) Review the sequence frequency calculations corresponding to each plant damage state to ascertain accuracy, uncertainty, completeness, and adequacy. Where the reviewers disagree with the PRA in a significant way
_9
. Project
Title:
Review of Seabrook Nuclear Power Plant FIN /189 No. A0801 Probabilistic Risk Assessment B&R No. 20-19-40-41-5 Wang No. 0473x/6-ll-84 (e.g., assumptions, failure rates, success criteria, omissions), the reviewers will reevaluate the sequence frequencies by performing localized calculations within the analysis to determine how alternative approaches would impact the sequence probabilities.
(n) Compare the dominant sequences corresponding to each plant damage state to existing PWR PRAs, generic data, and operating experience to help assure that no significant sequences are omitted.
(o) Assess the uncertainty analysis. Examine propagation and completeness in treatment of uncertainty, data uncertainty, and modeling sensitivity / uncertainty.
Task 2 External Events Evaluation (a) For each type of external event consioered, concur with or modify the estimated hazard curves, assess the completeness of the sequences considered for each plant damage state, assess the treatment of common cause interactions and hu .an errors, and evaluate the fragility or f ailure estimates of the components identified by the appropriate '
event / fault trees.
(b) Review the event and f ault trees to determine their accuracy, validity, and completeness for external events. Review and evaluate the implicit i and explicit assumptions of the external events analysis.
(c) Identify all known omissions and deficiencies in the external event analysis, and estimate the impact where possible. For those omissions and deficiencies for which evaluation is believed to be beyond the i state-of-the-art, provide a list and the basis for this belief.
(d) Review the sequence frequency calculations corresponding to each plant i
damage state to ascertain acciracy, uncertainty, completeness, and adequacy. Where the reviewers disagree with the PRA in a significant way (e.g., assumptions, failure rates, success criteria, omissions), the l
1 i
Project
Title:
Review of Seabrook Nuclear Power Plant FIN /189 No. A0801
- Probabilistic Risk Assessment B&R No. 20-19-40-41-5 Wane No. 0473x/6-11-84 reviewers will reevaluate the sequence frequencies by performing localized calculations within the analysis to determine how alternative approaches would impact the sequence probabilities.
(e) Assess the uncertainty analysis. Examine propagation and completeness in treatment of uncertainty, data uncertainty, and modeling sensitivity / uncertainty.
Task 3 Draf t Final Report on Tasks 1 and 2 (a) For each of the PRA areas (e.g., initiatinc events, initiating event _
frequencies, component f ailure rates, common cause f ailures, human reliability analysis, test and maintenance, event trees, f ault trees, success /f ailure criteria, external events, quantification, and uncertainties) determine if the analysis reflects appropriate use of risk ,
assessment methoos, plant / site information, and reliability data; cefine the basis for the fincing and describe what was considereo in the review.
The finding will include reestimates, as appropriate, of the dominant sequence f requencies corresponding to each plant damage state, icentification of areas that were not pursued and ioentification of grey areas where sensitivity studies might be used to bound a central estimate. .
(t) Describe areas of incompleteness (all known omissions and deficiencies) determined in the review. Quantify, where possible, the potential impact of these areas. Discuss the basis for quantification values.
(c) Based on the review of sequence calculations, discuss the accuracy, uncertainty, and adequacy of the PRA author's sequence quantifications.
(d) An approximate outline of the report is given here.
, Project
Title:
Review of Seabrook Nuclear Power Plant FIN /189 No. A0801 Probabilistic Risk Assessment B&R No. 20-19-40-41-5 Wang No. 0473x/6-ll-84
- 1. Executive Summary
- 2. Introduction
2.1 Background
2.2 Scope 2.3 Assumptions 2.4 Summary of Results and Insights Presented in the PRA
- 3. Internal Events Analysis 3.1 Initiating Events 3.2 Event Trees LOCA Transient Other 3.3 Success Criteria 3.4 Systems Descriptions Fault Tree Models 3.5 Human Factors 3.6 Faiiure Data 3.7 Operating Experience Analysis 3.8 Analysis Codes i 3.9 Accioent Sequences 3.10 Dependencies 3.11 Quantification
- 4. External Event Analysis 4.1 Seismic 4.2 Fire 4.3 Industrial Accioents 4.4 Other l
l l
l
Project
Title:
- Review of Seabrook Nuclear Power Plant FIN /189 No. A0801 Probabilistic Risk Assessment B&D No. 20-19-40-41-5 Wang No. 0473x/6-11-84
- 5. Summary and Conclusions 5.1 Dominant Sequences Corresponding to Each Plant Damage State 5.2 Important Problems and Omissions 5.3 Treatment of Uncertainties 5.4 Overall Evaluation of Seabrook Risk Assessment
- 6. Appendices (as required)
Task 4 Final Report The final report will take into account pertinent comments on the draf t final report by NRC and other interestec parties. It will be published as a NUREG/CR.
This task assumes that the NRC will respond within the 45 calendar days allowed for comments in the project schedule. Delay beyond this time will necessarily delay com;1etion of thi final report on a day-for-day basis.
Task 5 Questions to Licensee Provide questions for forwarding to the licensee covering significant all aspects of the systems analysis. (Responses already m&; have been received informally).
- 4. DESCRIPTION OF ANY FOLLOW-0N EFFORTS None.
- 5. RELATIONSHIP TO OTHER PROJECTS LLNL has developed and applied probabilistic risk assessment technology on the Reactor Safety Study, the Seismic Safety Margins Research Program (SSMRP), and various systems interaction studies for NRR. Information from the SSMRP will be used in the evaluation of the camponent fragility or failure estimates. In addition, information developed as a result of work done on the Seismic Hazarc Characterization of the Eastern U.S. will be used, as appropriate, in the i
i l
. Project-Title: Review of Seabrook Nuclear Power Plant FIN /189 No. A0831
. Probabilistic kisk Assessment B&R No. 20-19-40-41-5 Wang No. 0473x/6-11-84 external event evaluction of the seismic hazard curve for the plant site.
Some information from a DOE prograt to assess natural hazards at a number of L'0E sites may be used.
- 6. REPORTING REQUIREMZNTS 6.1 Technical Reports Upon completion of Task 3, LLNL will formally submit a draft final report covering Tasks 1, 2, 'and 3 as defined in Task 3. Upon completion of Task 4, LLNL will submit the final report which takes into account industry and NRC comments. Upon completion of Task 5, LLNL will submit questions for forwarding to the licensee. ,
6.2 Business Letter Report A monthly business letter will be submitted at the end of each month of effort to the Project Manager with copies to the Director, Division of Saf ety Technology, ATTN: J. Halvorsen; A. Tnacani, DST; F. Rowsome, DST; R. Frahm, DST; and L. Solancer, NRR. These reports will identify the title of the project, the FIN, the Principal Investigator, the period of performance, anc the reporting period and will contain 3 sections as follows:
Project Status Section
- i. A listing of the efforts completed during the period; milestones reached, or if missed, an explanation provioed. ;
ii. Any problems or delays encountered or anticipated and recommendations for ,
resolution. 1/
i l
1/
If the recommended resolution involves a contract modification, i.e.,
change in work requirements, level of effort (costs), or period of performance, a separate letter shoulo be preparea and submitted to the
~
4 Director, Division of Safety Technology, ATTN: J. Halvorsen anc a copy provided to the NRR Project Manager and L. Solander, NRR.
l
\
i
- - ~ _ _ _ - , , - - . . . , _ , , - - _ . - _ . - . - _ . _ - .--_ _ ,_., _ ,,_ ..--- -- - _ .- - -,,-- _ - - - - , - , -
. Project
Title:
Review of Seabrook Nuclear Power Plant FIN /189 No. A0801 Probabilistic Risk Assessment B&R No. 20-19-40-41-5 Wang No. 0473x/6-il-84 iii. A summary of progress to date (this may be expressed in terms of percentage completion for the project).
iv. Plans for the next reporting period.
Financial Status Section
- i. Provide the total cost (value) of the project as reflected in the proposal (NRC Form 189), the total amount of funds obligated to date, the balance of funds required to complete the work by fiscal year, and a summary of costs as shown in Attachment A.
ii. Provide the estimated total amount of f unds expended (costed) during the period prior to the report period and cumulative to date (see Attachment A).
Fee Recovery Cost Status Section Pursuant to the provisions of NRC Regulations, 10 CFR 170, provice the total 4 amount of funos expenced (costed) curing the period and cumulative to date and report them jp1 a separate page as part of this report in the format shown in the second page of Attachment A:
- 7. SUBCONTRACTS, CONSULTANTS AND/OR MATERIALS We anticipate the use of subcontractors and consultants to assist in this work. The two subcontractors and one consultant listed below have already l
been specifically identified, others may also be used.
- a. Subcontractors (1) Applied Risk Technology Corporation (ARTECH); P. J. Amico (2) Jack R Benjamin and Associates, Inc. (JBA); J. W. Reed, M. W. McCann, Jr.
- b. Consultants (1) P. R. Davis t
I L
. . . . . . ..- - . = - _ . . .
'-Project
Title:
Review of SeaDrook Nuclear Power Plant FIN /189 No. A0801 Probabilistic Risk Assessaent B&R No. 20-19-40-41-5 f Wang No. 0473x/6-il-84
- 8. LIST NEW CAPITAL EQUIPMENT REQUIRED Not Applicable.
- 9. DESCRIBE SPECIAL FACILITIES REQUIRED Not Applicable.
- 10. CONFLICT OF INTEREST INFORMATION No known conflicts or apparent cor.flicts of interest.
- 11. MEETINGS AND TRAVEL o Contractor may attena a 2-day visit at an unspecified site with the licensee to ciscuss questions on his analysis and may attend six l-day meetings at NRC heacquarters in Washington, D.C. for four participants.
J o Four individuals may concuct two three-day visits to the Seabrook site to look for potential common cause vulnerabilities, review of control operations, ano a general overview of the plant layout and potential idiosyncrascies.
- 12. NRC FURNISHED MATERI ALS The NRC staff will furnish LLN'. with copies of the following documents: ;
- i. The Probabilistic Risk Assessment (PRA)
< ii. The plant's Final Safety Analysis Report (FSAR) lii. The question and answer volumes of the FSAR, if applicable I
iv. A set of P&l0's for the plant Other material may be requested as required.
4
- 13. PROPRIETARY DATA In the event any proprietary information is submitted by the NRC in connection with this project, it must be specifically identified. The University agrees to exercise its best efforts to protect such proprietary data. Furthermore, j
i
- , . - .-._.-.,,,,-,,.._._,,,_,,,x. ,,c,~ . . , , , , , , ,.m.,,- mm., .-, , . - _ ,_ , - , - , _ . . . . . . . ~ . , . , - , - - , , - - . . - - , - , , . - _ , - - r t--
Project
Title:
Review of Seabrook Nuclear Power Plant FIN /189 No. A0801 Probabilistic Risk Assessment B&R No. 20-19-40-41-5 Wano No. 0473x/6-il-84 limitation shall not be imposed on the use of- any information and data previously delivered to the University or government without limitations or previously published in any form as to be generally available.
- 14. PATENT STATUS Not Applicable.
- 15. TASK "X" ON-CALL ASSISTANCE Not Applicable.
- 16. SUMMARIZE DELIVERABLES At the completion of the project a final report will be submitted summarizing all project work and results.
l ATTACHMENT A MONTHLY PROJECT FINANCIAL STATUS (Month)
Review of the Seabrook Probabilistic Risk Assessment FIN-A0801 A. PROJECT COSTS:
Total Projected Funds Obligated Balance of Funds i Project Cost to Date by Fiscal Year FY84 FY85
$ K $ K $ K $ K B. COST ANALYSIS
- Period Cumulative Direct Lab Staff Effort - FTE Direct Salaries $ K $ K Materials & Services ADP Support Subcontracts Travel Expenses Indirect Labor Costs Other (TID)
, General & Aaministrative Total Expenses S K $ K i
Liens Total Costs and Liens $ K
( %) of
! funding available
- Note: These figures are for cost analysis only and may differ slightly from final oilling figures.
i 1
ATTACHMENT A (continued)
C. FEE RECOVERY COST STATUS FIN: A0801 TITLE: Review of the Probabilistic Risk Assessment for the Seabrook Nuclear Power Plant PERIOD: (Month)
Docket Costs Facility Name Number Perioo Cumulative Seabrook 50-443 $ K $ K Common Costs 2/ 50-900 Total Expenses $ K $ K 2_/ Common costs are for those costs incurred for effort such as preparatory or start-up efforts to interpret and reach agreement on methodology, approach, acceptance criteria, regulatory position, or TER f ormat; efforts associated with the " lead plant" concept that might be involvec during the first one or two plant reviews as estimated by the contractor; meetings / discussion involving the above efforts to provide orientation, background knowledge, or guidance at the beginning or during performance of work; and any technical effort applied to a category of f acilities, e.g., reactor analyses on all BWR facilities. In the case of the latter example, these costs should be prorated equally to only those f acilities to which the effort applies.
Development of methodologies, criteria, or technical positions are not fee-recoverable and, therefore, should not be categorized as common costs.
Management and related support costs chargeable directly to the effort are not i to be reported as common costs and should, therefore, be charged in proportion l to the other direct costs associated with those f acilities during the
- reporting period.
NOTE: Comon costs are to be accrued on a monthly basis and prorated equally among the facilities identified under the effort at the end of each fiscal
! year or at the completion of the effort, whichever occurs first.
l l
- 'o E' 1 UNITED STATES s g NUCLEAR REGULATORY COMMISSION
.p WASHINGTON. D. C. 2o555
\...../ .
JtJN 2 1 1984 -
MEMORANDUM FOR: D. Eisenhut, Director, DL R. Vollmer, Director, DE R. Mattson, Director, DSI H. Thompson, Director, DHFS FROM: Themis P. Speis, Director Division of Safety Technology
SUBJECT:
REVIEW OF THE SEABROOK STATION PROBABILISTIC SAFETY ASSESSMENT A Probabilistic Safety Assessment (PSA) for the Seabrook Station Nuclear
- Power Plant was voluntarily performed and submitted to NRC by Public Service Company of New Hampshire, an OL applicant. The Reliability and Risk Assessment Branch (RRAB), Division of Safety Technology, has the responsibility for the overall coordination of the review effort with the support of Lawrence Livermore National Laboratory contracted to review the front-end (accident initiation through plant damage state) portion of the PSA.
In view of the circumstances under which this PSA was submitted and the current status of the licensing of the Seabrook Station, the purpose and focus of this review will vary in some ways from ongoing and previous reviews of probabilistic safety assessments. To elaborate, due to the voluntary nature of the decision to. perform and submit a PSA for Seabrook, a strictly narrow focus of verifying the accuracy of the numbers presented by extensive requantification or phenomenological analyses would not be an appropriate use of review resources.
Primary foci, as in other reviews, would remain to be the identification of significant vulnerabilities or weaknesses in design and proposed operation that may not have been considered in deterministic analyses, the identification of significant safety issues that may have generic implications, and the l identification of any major problems that would be expected to significantly affect the results of the analysis and the safety of the plant. These
- conclusions No. willand 40, No. 39, then be16, No. dealt with in1.accordance with NRR Office Letters Revision
{
In addition, the Seabrook PSA represents one of the latest PSAs which has incorporated lessons learned from past studies and advancements in the
- state of-the art of probabilistic safety analyses. An emph3 sis of the review should be to glean any new information that may be useful or affect the reviews of specific safety issues or other programs.
f6 f 8- 8'l* " b k &Whb {
l
- . - _ = _.
1
)t JUN 21 E84 2-The possibility of the PSA being used in the Phase II hearings for the Seabrook Station should be kept in mind. The hearings.are expected to take place in late CY 1984/early 1985. The issue of emergency planning is expected to be a prominent part of these hearings which is a likely area where there may be use of risk assessment results.
The schedule for this review calls for preliminary findings being submitted to RRAB by October 15, 1984. Enclosed with this memo is a delineation of portions of the PSA to be reviewed by the designated divisions (s) with guidance as to the type of review being requested. We would like to have any questions on significant areas for transmittal to LLNL for consideration in their review, or if needed, to be discussed with the applicant, by August 1, 1984 so that resolution and incorporation in the preliminary report from LLNL will take place as early as possible in order to expedite the finalization of the review document. In consideration of the circumstances and nature of this review, we are planning on only one site visit. The date of this visit must be coordinated with all necessary participants, (i.e., contractors, subcontractors and reviewers) so as to minimize the burden of time and resources expended on this review by the utility. We would also like to emphasize that there be close coordination between the front-end and ,
back-end reviewers in DST and DSI and respective contractors so that the final review will be a cohesive, integrated assessment of the Seabrook Station.
The Division of Engineering will support RRAB in overseeing the review effort by LLNL on external events.
The final product of the review will be in the form of a NUREG/CR. There remains the possibility of SERs or testimony being required in support of the licensing of Seabrook.
Sarah M. Davis, of RRAB is the coordinator for the Seabrook PSA Review. -
Ms. Davis can be contacted on X27546.
c r M %
Themis P. Speis, Director Division of Safety Technology
Enclosure:
Proposed Review Schedule i
L
h JUN 21584 Proposed Schedule ,
LLNL - Review through plant damage state -
Identification of major errors or inconsistencies. Estimation of impact on dominant accident sequences and revised estimates where appropriate. Summary of results, review conclusions, and major insights gained.
10/15/84 Oraft Report Internal NRC Review DST - Review to core damage state, Generic Safety Issues (medium and high priority), potential new GSIs, and overall coordination.
. OSI - Critique of the containment failure analysis identifying strengths and weaknesses of containment design and critique of release category assignment. Provide major insights in this area and any significant variations in the conditional failure probabilities and release fractions. A brief review of consequence analysis should also be performed. Based on the results of the consequence review, containment failure conditional probabilities, and release fractions, limited consequence analysis may be needed.
10/15/84 Draft Report (Critique and Conclusions)
DE - Support in overseeing the contractor review of external events.
Please provide a critique of the external events analyses (e.g.,
seismic, fire, etc.) contained in the Seabrook PRA with the appropriate support from other Branches / Divisions (e.g., ASB, METB, etc.). Any questions or comments to be transmitted to the contractor should be formulated and submitted to RRAB by August 1, 1984.
10/15/84 Oraft Report (Critique and Conclusions)
Other - Upon receipt of the contractor report (10/15/84), we will request Support review support and limited calculations where appropriate from other Divisions and Branches in areas of their expertise, especially for those areas where reestimates were made which affect the set of dominant sequences and overall results of the PRA. Designation of specific sections to be reviewed will be transmitted to each Branch / Division at that time.
Y