ML20062F271
| ML20062F271 | |
| Person / Time | |
|---|---|
| Site: | Limerick  |
| Issue date: | 07/06/1982 |
| From: | Abelson H Office of Nuclear Reactor Regulation |
| To: | Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 8208120003 | |
| Download: ML20062F271 (58) | |
Text
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DISTRIBUTION:
See attached page iDocket Nos:250-352/353i APPLICANT: Philadelphia Electric Company FACILITY:
Limerick Generating Station
SUBJECT:
SUMMARY
OF MAY 14, 1982 PRA MEETING A meeting was held with Philadelphia Electric Company on May 14,1982, at the Sheraton - Valley Forge Hotel in King of Prussia, PA to discuss Rev. 3 t
to the Probabilistic Risk Assessment (PRA) for the Limerick Generating Station.
Revision 3 responds to a letter of January 18, 1982 from A. Schwencer of NRC to E. Bauer of PECO, requesting that PECO update the PRA to reflect changes in computed risk resulting from design / operational modifications to the baseline May 1980 design (on which the original PRA is based).
Additional agenda items included a brief discussion of several NRC questions related to the Limerick site tour conducted on the previous day and a presentation by NRC/BNL on the current status of the PPA review. A list of attendees and the meeting agenda are provided in Enclosures 1 and 2, respectively. Copies of the visual aids used in the presentations are found in Enclosures 3 through 6.
Highlights of the meeting are summarized below.
Significant changes reflected in PRA Rev. 3 include a Limerick-specific ATWS Alternate 3A fix, deletion of the containment overpressure relief (COR) system,'and more detailed fault tree construction.
- Feattms of the ATHS design are illustrated in Enclosure 3.
The SLC system now includes 3 pumps (instead of 2), improved automatic system initiation, and on-line test capability.
fiodifications to the system fault trees and updated system unavail-abilities are summarized in Enclosure 4 Improved treatment of common-mode failures, improvements in repatr/ restoration models, a re-evaluation of nperator error, and system design changes are reflected in the revised fault trees. PECO noted that almost all failure rate data employed in Rev. 3 is the same as used in previous revisions.
8208120003 820706 i
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2 Event tree structure changes include elimination of the COR system, expanded loss of offsite power event trees (to include all sequences),
updated medium LOCA success criteria for decay heat removal, and other modifications as noted in Enclosure 4.
A comparison of revised and previously comouted core melt frequencies for four event sequence classes (see Enclosure 4) indicate only minor differences.
Risk comparisons between Limerick and the WASH-1400 reference plant are illustrated in the CCDF curves found in Enclosure 5.
These curves delineate the effects of design differences, site differences, and differences in data and methodology employed in the Limerick and WASH-1400 PRAs. Sensitivities to the elements comprising the overall site difference such as meteorology, population, and evacuation data are not presented, however. Sensitivities to Limerick-specific design features are likewise not presented. However, the ATWS fix represents the dominant contributor to reduced risk.
The NRC/BNL presentation on the current PRA review status (see
- ) included a preliminary outline of the NUREG/CR to be issued in November 1982, a detailed description of the BNL review effort, a summary of accomplished milestones, and a discussion of future review milestones.
Harvey Abelson, Project Manager Licensing Branch No. 2 Division of Licensing Enclosures :
As stated cc: See next page
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JUL 6 ISBZ MEETING
SUMMARY
DISTRIBUTION:
DATE:
Document Control (50- 352 )
~
LB#2 Reading File NRC PARTICIPANTS:
EHylton Project Manager H. Abelson B. Hardin E. Case F. Coffman D. Eisenhut/R. Purple E. Chelliah R. Tedesco S. Lewis J. Youngblood S. Ebneter A. Schwencer W. Lazarus F. Miraglia H. Abelson E. Adensam SS PB G. Lainas W. Russell D. Crutchfield T. Ippolito J. P. Knight N
hns on D$
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cc: See next page T. Speis R. Houston L. Rubenstein F. Schroeder M. Ernst J. Kramer Attorney, OELD S. Lewis 01&E i
Region I
l Resident Inspector 4
i ACRS (16)
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Limerick Mr. Edward G. Bauer, Jr.
Vice President & General Counsel Philadelphia Electric Company 2301 Market Street Philadelphia, Pennsylvania 19101
.cc:
Troy B. Conner, Jr., Esquire Mr. Marvin I. Lewis Conner and Wetterhahn 6504 Bradford Terrace 1747 Pennsylvania Avenue, N. W.
Philadelphia, PA 19149 Washington, D. C. 20006 Frank R. Romano, Chairman Mr. Robert W. Adler Air & Water Pollution Patrol Assistant Counsel 61 Forest Avenue Commonwealth of Pennsylvania, DER Ambler, PA 19002 505 Executive House P. O. Box 2357 Charles W. Elliott, Esquire Harrisburg, Pennsylvania 17120 Thonas & Hair 123 North Fifth Street Honorable Lawrence Coughlin Allentown, PA 18102 House of Representatives Congress of the United States Judith A. Dorsey, Esquire Washington, D. C. 20515 Limerick Ecology Action 1315 Walnut Street, Suite 1632 Roger B. Reynolds, Jr., Esquire Philadelphia, PA 19107 324 Swede Street Norristown, Pennsylvania 19401 Mr. Karl Abraham Public Affairs Officer Lawrence Sager, Esquire Region I Sager & Sager Associates U.S. Nuclear Regulatory Commission 45 High Street 631 Park Avenue Pottstown, Pennsylvania 19464 King of Prussia, PA 19806 Joseph A. Smyth Mr. Jacque Durr Assistant County Solicitor Retident Inspector County of Montgomery U.S. Nuclear Regulatory Commission Courthou se P. O. Box 47 Norristown, Pennsyl vania 19404 Sanatoga, PA 19464 Eugene J. Bradley James M. Neill, Esquire Philadelphia Electric Company Associate Counsel for Del-Aware Associate General Counsel Box 511 2301 Market Street Dublin, PA 18917 Philadelphia, Pennsylvania 19101 l
Joseph H. White III Mr. Vincent Boyer 11 South Merion Avenue Senior Vice President Byrn Mawr, PA 16801 Nuclear Operations Philadelphia Electric Company 2301 Market Street Philadelphia, Pennsylvania 19101 l
l
s s
. Thomas Gerusky, Director Sugarman & Denworth Bureau of Radiation Protection Suite 510 Dept. of Environmental Resources.
North American Building 5th Floor, Fulton Bank Bldg.
121 South Broad Street Third & Locust Streets Philadelphia, PA 19107' Harrisburg, PA 17120 Donald S. Bronstein, Esq.
Director, Pennsylvania Emergency The National Lawyers Guild Management Agency Third Floor.-
Basement, Transportation &
1425 Walnut Street Safety Building Philadelphia, PA 19102 Harrisburg, PA 17120 Lawrence Brenner, Esq., Chairman
- John Shniper Administrative Judge Meeting House Law Bldg. & Gallery U.S. Nuclear Regulatory Commission Mennonite Church Road Washington, D.C.
20555 Schuykill Road (Rt. 724)
Spring City, PA 19475 Dr. Richard F. Cole
- Administrative Judge Robert L. Anthony U.S. Nuclear Regulatory Commission i
Friends of the Earth of the Washington, D.C.
20555 Delaware Valley 103 Vernon Lane, Box 186 Dr. Peter A. Morris
- Moylan, PA 19065 Administrative Judge U.S. Nuclear Regulatory Commission W. Wilson Goode Washington, D.C.
20555 Managing Director City of Philadelphia Philadelphia, PA 19107 William A. Lochstet 119 E. Aaron Drive State College, PA 16801 Walter W. Cohen -
Consumer Advocate i
Office of Attorney General 1425 Strawberry Square Harrisburg, PA 17120 Steven P. Hershey, Esquire Consumers' Education & Protective Association Sylvania House Juniper & Locust Streets Philadelphia, PA 19107 Alan J. Nogee The Keystone Alliance 3700 Chestnut Street Philadelphia, PA 19104
ATTENDANCE LIST May 14,1982 Name Affiliation TF.-~Abel so n NRG B. Hardin NRC F. Co f fma n NRC E. Chelliah NRC S. Lewis NRC K. Shiu BNL L. Lederman BNL R. Karol BNL T. Pratt BNL R. Bari BNL
,/'
op S. Fiarman BNL Q
fo, I. Papazoglou BNL d 'k[
R. Earle GE g) s T. Shannon PEC0 9'
/
L. Frederick GE gs C. Rush PECO r>
g S. Ebneter NRC H. Careway GE D. Helwig PECO E. Burns SAI R. George PECO J. Doering PEC0 G. Edwards PECO M. Wetterhahn Conner & Wetterhahn H. Hansell PECO W. Lazarus NRC R. Harper PECO S. Maingi PA Dept. of Environmental Resources A. Nogee Keystone Alliance J. Dorsey Limerick Ecology Action G. Daebel er PECO V. Boyer PECO R. Logue PECO R. Could University of Pennsylvania E. Schmidt NUS
AGENDA FOR LIMERICK PRA TECHNICAL REVIEW MEETING MAY 14, 1982 MORNING SESSION (8:30 AM) 1.
PRESENTATION BY PECO ON REVISION 3 TO LIMERICK PRA INCLUDING:
A)
SYSTEM CHANGES B)
FAULT TREE AND EVENT TREE CHANGES C)
IMPACT ON CORE MELT FREQUENCY AND RISK CURVES D)
COMPARISON OF NEW RISK CURVES WITH WASH-1400 CURVES 2.
DISCUSSION (NRC, BNL, PECD, CONSULTANTS) ON AB0VE MATERIAL AFTERNDON SESSION 1.
DISCUSSION (NRC, BNL, PECO, CONSULTANTS) 0F PRA ITEMS RELATED TO LIMERICK SITE VISIT CONDUCTED ON PREVIOUS DAY.
2.
NRC/BNL PROGRESS OF REVIEW 0F LIMERICK PRA.
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AGENDA
- INTRODUCTION P.E.Co.
i 8 SIGNIFICANT SYSTEM CHANGES P.E.Co.
4 e FAULT TREES / EVENT TREES G.E.
1
- CORE MELT G.E.
n s
G a
e CCDF's G.E.
I
REVISION
)
e RESPONDS TO 1/18/82 LETTER
- UPDATES THE 1980 LGS MODELS
'~'
~
e PROVIDES ADDITIONAL TEXT CLARIFICATION O DELETES COR 4 INCLUDES LGS ATWS 3A 9 PROVIDES MORE COMPREHENSIVE FAULT TREES
l l
ATWS DESIGN l
- LIMERICK DESIGN CONSISTENT WITH i
l ALTERNATE 3A IN NUREG-0460, VOLUME 4 e DESIGN INCLUDES LIMERICK UNIQUE FEATURES r
I 1
i
I ATWS INITIATION e HIGH REACTOR PRESSURE OR e LOW REACTOR WITER LEVEL AND e APRM'S NOT DOWNSCALE v
i
S 9
ATWS DESIGN FEATURES e ALTERNATE ROD INSERTION (ARI) i G-RECIRCULATION PUMP TRIP (RPT)
9 MSIV ISOLATION SETPOINT CHANGE I
9 AUTOMATIC 129 GPM STANDBY LIQUID CONTROL SYSTEM (SLCS) t M
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i 4/82 LIMEP,1CK GENERATING STATION PRA TASK
SUMMARY
8 REVISE / UPDATE FAULT TREES IN RESPONSE TO PECO SYSTEM REVIEW COMMENTS S UPDATE FAULT TREES FOR IMPROVED ADS PNEUMATIC SYSTEM 4 UPDATE FAULT TREES FOR MODIFIED ALT. 3A SLC SYSTEM e REVISE / UPDATE RHR SYSTEM FAULT TREES FOR:
1.
DESIGN CHANGES 2.
IMPROVED REPAIR / RESTORATION MODEL 3
REVALUATION OF OPERATOR ERROR 9 REVISE FW T, PCS FUNCTIONAL FAULT TREES S EVALUATE LIMERICK WITHOUT CONTAltNENT OVERPRESSURE RELIEF FUNCTION R. T. EARLE GENERAL ELECTRIC CO.
5/11/82 1
s J
]
COMPARISCt1 OF RESULTS UNAVAILABILITY i
SYSTEM 3/81 4/82
-2 j
HPCI 9.6X10-7.1X10
-2
-2 i
RCIC 7.8X10 6.5X10
-3
-3 LPCI 1.7X10-3 1.8X10
-3
-3 LPCS 6.2X10 2.6X10
-5
-3
-3 ADS - TOTAL 6.6X10 6.5X10
-5
- MECHANICAL
- 9. 7X10-7.9X10
-5 ADS MECH. AND 5.0X10-8.3X10 (LPCI OR LPCS)
-2 SLC 1.8X10 9.0X10-
-5
-5 I
ELECTRIC POWER 2.9X10 4.7X10
- 2. ! X10-7.1X10 RHR - SYSTEM 3.9X10-1.6X10- R PRESSURIZED X
-6 I
- FUNCTION 1.1X10-9.8X10 R PRESSURIZED
-6 8.5X10 R DEPRESSURIZED x
FEEDWATER COMPONENTS 7.2X10-
-2
-2 FEEDWATER FUNCTION 2X10 1.8X10 (TURBINE TRIP) 1 l
2 i
4 LIMERICK GENERATING STATION SYSTEM FAULT TREES FOR 4/82 PRA i
R. T. EARLE 7
GENERAL ELECTRIC CO.
5/11/82 i
3
LPCI O SYSTEM UNAVAILABILITY 3/81 4/82
-3 1.7X10-3 1.8x10 e MAJOR TREE CHANGES
- RESTRUCTURED EXISTING TREE
- DELETED 6" LINE AS VIABLE LPCI ALTERNATE PATH
- DELETED MIN FLOW VALVE AS POSSIBLE SYSTEM FAILURE
- ADDED DUAL STRAINERS ON PUMP INLET LINES
- UPDATED PUMP ROOM COOLING SYSTEM
- DELETED STE44 SUPPLY LINE AS A VI ABLE CROSSOVER PATH
- MAINTENANCE CHANGED TO PER LEG CRITERIA
- DELETED LPCI AND LPCS COMMON MODE STRAINER FAILURE (1.0x10-)
4
LPCS S SYSTEM UNAVA_lLABILITY 3/81 4/82 6.2X10-3 2.6X10-3 9 MAJOR TREE CHANGES
- UPDATED PUMP ROOM COOLING SYSTEMS
- ADDED DUAL STRAINERS ON PUMP INLET LINES
- DELETED "DHIGH" - ERROR OF COMMISSION
- DELETED EXTERNAL PUMP MOTOR LUBE SYSTEM
- UPDATED 1rdikUMt.NI Allori IDENTIFICATION
- DELETED R PRESSURE INSTRUMENTATION " LACK OF X
TESTING COf00N MODE FAILURE".
l l
1 5
SLC 4 SYSTEM UNAVAILABILITY FAILURE OF ALL PUMPS 3/81 4/82
-2 1.8X10 9.0x10~
e t%JOR TREE CHANGES
- MODIFIED ATWS ALTERNATE 3A DESIGN (NUREG - 0460)
- FEATURES 1.
3 SLC PUMPS (INSTEAD OF 2) 2.
ON LINE TEST CAPABILITY 3.
IMPROVED AUTOMATIC SYSTEM INITIATION 4
REDUCED NUMBER OF SINGLE POINT SYSTEM FAILURES e MAJOR AVAI LABILITY IMPROVEMENTS 3/82 4/82
-2 MAINTENANCE 1.2X10 1.0X10'
-2 '
-5 INITIATION 1.1X10 7.3X10
-3 PUMPS 1.8X10 1.2X10'
-3 R DELIVERY 1.7X10 6.1X10~
X
' DOMINATED BY FAILURE OF FLUX AND ROD POSITION PERMISSIVES.
6
ADS S
SYSTEM UNAVAILABILITY 3/81 4/82
-3
-3 6.6X10 6.5X10 4
MAJOR TREE CHANGES INCORPORATED ADS AIR SUPPLY SYSTEM IMPROVEMENTS REFERENCE NUREG - 0737 ITEM II.K.3.2B CORRECTED NUMBER OF ADS VALVES REQUIRED (2 VS 3)
UPDATED FAULT TREE 1.
REDUNDANT AIR SOLENOIDS 2.
INSTRUMENTATION & LOGIC IDENTIFICATION ADDED MISSING LEVEL 1 PERMISSIVE LOGIC 8
UNAVAILABILITY
SUMMARY
3/81 4/82
-3
-3 INITIATION SIGNAL 6.0X10 6.5X10
-5 ADS MECHANICAL 9.7X10-7.9X10 7
o RHR e
SYSTEM UNAVAILABILITY RHR FUNCTION 3/81 4/82
-6 1.1X10-9.8X10 (R
PRESSURIZED)
X 8.5X10-6 (R DEPRESSURIZED) y e
MAJOR TREE CHANGES SEPARATE ANALYSIS FOR R PRESSURIZED AND X
DEPRESSURIZED CASES (USE DETERMINED BY EVENT TREE SEQUENCE) 1.
COOLING MODES WITH R PRESSURIZED X
SUPP. POOL COOLING CONTAINMENT SPRAY 2.
ADDITIONAL COOLING MODES WITH R X DEPRESSURIZED R
S/D COOLING X
ALTERNATE R COOLING (LPCI LOOP)
X ADDED PUMP DISCHARGE CROSSOVER VALVES INCLUDED REMOTE MANUAL OPERATION OF FAILED MOV VALVES 4 RHR SW PUMPS AVAILABLE UPDATED RHR SW TREE USED SINGLE, UNIFIED OPERATOR ERROR FOR RHR REPAIR FUNCTION MODELED AT COMPONENT LEVEL 8
RHR (CONTINUED)
O SYSTEM UNAVAILABILITY 3/81 FACTOR 4/82 FACTOR BASE CASE 3.9X10 -
3.9X10-2 RHR S/W PUMPS NO CROSSOVER VALVES NO REPAlR/ RESTORATION SYSTEM UPDATE 1.6X10-2.4 4 RHR SW PUMPS PUMP CROSSOVER VALVES RCIC/RHR STEAM 2.3X10-1.7 NO CREDIT CONDENSING MODE REPAIR S RESTORATION VALVES 1.0X10 -
1.6/3.9
-6 VALVES S COMPONENTS 1.1X10' 2/3.5 9.8X10 10.2/40 e
3/81 VS 4/82 RHR CHANGE FACTOR
=
11 9
1 MMERICK GENERATING STATION EVENT TREES FOR 4/82 PRA R.
T.
EARLE GENERAL ELECTRIC CO.
5/11/82 l
l 10 l
SUMMARY
OF EVENT TREE STRUCTURE CHANGES I
FOR THE TURBINE TRIP, MANUAL S/D AND ISOLATION EVENT TREES - "Q" INCLUDES F/W AND PCS AVAILABLE.
O EXPANDED LOSS OF OFFSITE POWER EVENT TREE (S) TO INCLUDE ALL EVENT SEQUENCES.
8 INCORPORATED UPDATED MEDIUM LOCA SUCCESS CRITERIA FOR DECAY HEAT REMOVAL.
8 DELETED SRV OPEN/ CLOSING PROBABILITIES FOR MANUAL S/D.
O EVENT TREES QUANTIFIED WITHOUT THE CONTAINMENT OVERPRESSURE RELIEF SYSTEM.
l 11
I CLASS I VARIETY EVENTS CHANGE
SUMMARY
CORE MELT FREQUENCY (PER YEAR)
CHANGE SEQUENCE MAJOR EFFECT 3/81 4/82 FACTOR
-6
-6 T
UX
- HIGH PRESS SYS 6.4X10 5.5X10 1.2
-6
-7 T
- HIGH PRESS SYS 1.7X10 2.2X10 7,7
- ADS MECH
- LOW PRESS SYS
-6
-6 T
- HIGH PRESS SYS.
4.8X10 6.7X10
_3,q E
- ADS MECH
- LOW PRESS SYS.
- D/G
- METHODOLOGY CHANGE TOTAL 1.3X10-5 1.2X10-5 1.08 PERCENT TOTAL CORE 84.4%
83.01 MELT FREQUENCY 12
CLASS 11 VARIETY EVENTS CONTAINMENT HEAT REMOVAL CLASSIFICATION
SUMMARY
NO.
SYSTEM DESCRIPTION 1.
PCS NORMAL SHUTDOWN MODE - NO HEAT INPUT TO SUPP. POOL 2.
PCS OR RHR RHR MUST BE INITIATED IF THE PCS CAN'T BE RECOVERED.
3.
RHR RHR MUST BE INITIATED - EXISTING CONDITIONS PREVENT SUCCESS OF THE PCS i
13
CONTAINMENT HEAT REMOVAL CLASSIFICATION NO. 1 9
NORMAL SHUTDOWN MODE (PCS)
FW G PCS REMAINS ON LINE OR RESTORED (FW WITHIN 30 MIN.)
5/R VALVES RECLOSE NON LOCA EVENT NO HEAT ADDITION TO S/P DELAYED REQUIREMENT FOR PCS S
APPLICABLE EVENTS TURBINE TRIP MANUAL S/D ISOLATION (MSIV CLOSURE, LOSS OF F/W, LOSS OF COND. VACUUM) e CORE MELT FREQUENCY (PER YEAR) 3/81 3/81 4/82 W/O COR
-8 4.2X10~
1.5X10-5 8.4X10 14
CONTAINMENT HEAT REMOVAL CLASSIFICATION NO. 2 4
PCS OR RHR HEAT ADDITION TO SUPPRES$10N POOL (HPCI, RCIC, SRV'S)
PCS MUST BE RECOVERED 20 HOUR REPAIR / RESTORATION TIME AVAILABLE SYS. CHANGE FACTOR - (COMPARED TO 3/81 W/O COR)
PCS 4
RHR 11 6
CORE MELT FREQUENCY (PER YEAR)
CHANGE 3/81 3/81 W/O COR 4/82 FACTOR
-7
-6
-7 2.2x10 7.8X10 3.6x10 48 15
CONTAINMENT HEAT REMOVAL CLASSIFICATION NO. 3 8
RHR ONLY SEQUENCES WITH HEAT ADDITION TO S/P 1.
MULTIPLE SORV 2.
UNTIMELY SCRAM W/10RV 3.
LARGE LOCA PCS IS NOT SUCCESSFUL RHR SYSTEM MUST BE INITIATED 20 HOUR REPAIR / RESTORATION TIME 9
CORE MELT FREQUENCY (PER YEAR)
CHANGE 3/81 3/81 W/O COR 4/82 FACTOR
-6 2.2X10~
7.6X10 7.1X10~
11 16
SUMMARY
OF CLASS II VARIETY EVENTS CORE MELT FREQUENCY (PER YEAR)
NO. DESCRIPTION 3/81 4/82 1.
NORMAL SHUTDOWN MODE 4.2X10~
~
8.4X10 2.
~
1.6X10 3.
RHR 2.2X10~
~
7.1X10
-7
~7 TOTAL 6.SX10 9.6X10 i
PERCENT TOTAL CORE MELT FREQUENCY S7 6.4 W
17 g~: ; _::-. e
.. - ~. -. - -. -. - -
.m.
e 9
CLASS 111 VARIETY EVENTS CORE MELT FREQUENCY (PER YEAR) 3/81 4/82
,i
-7 SLC SEQUENCES 2.0X10-1.0X10 OTHER 1.2X10-1.0X10-1
-6 TOTAL 1.4X10 1.1X10 -'
PERCENT TOTAL CORE MELT FREQUENCY 9.3 7.3 l
18 l
,,,y
CLASS TV VARIETY EVENTS CORE MELT FREQUENCY (PER YEAR) 3/81 4/82
~0 SLC SEQUENCES 7.4X10 2.4X10~
-8
~7 OTHER 5.6X10 1.1X10
~7 TOTAL 1.3X10~
1.'3X10 PERCENT CORE MELT FREQUENCY 0.9 0.9 I
19
6 8
SUMMARY
CORE MELT FREQUENCY (PER YEAR) 3/81 4/82 CLASS VARIETY
-5
~S 1
1.3X10 1.2X10
-7
~7 2
8.5X10 9.6X10
-6
-6 3
1.4X10 1.1X10 4
1.3X10-1.3X10
-5
-5 TOTAL 1.5X10 1.5X10 1
20 1
l 1
9 0
HPCI 4
SYSTEM UNAVAILABILITY 3/81 4/82 9.6X10~
7.1X10 ~
e MAJOR TREE CHANGES UPDATED INSTRUMENTATION IDENTIFICATION ADDED MISCALIBRATION OF INDIVIDUAL SENSOR CHANNEL (S)
UPDATED PUMP ROOM COOLING SYSTEM REVISED SENSOR FAILURE & DETECTION PROBABILITY ADDED DUAL STRAINERS ON PUMP INLET LINE REMODELED CST /SP SUPPLY TRANSFER FUNCTION 21
8 9
RCIC e
SYSTEM UNAVAILABILITY 3/81 4/82 7.8X10' 6.5Xio-2 9
MAJOR TREE CHANGES UPDATED TREE TO INCLUDE CST /SP AUTO TRANSFER FUNCTION UPDATED INSTRUMENTATION IDENTIFICATION - SEPARATE LEVEL SENSORS ADDED MISCALIBRATION OF INDIVIDUAL SENSOR CHANNEL (S)
DELETED MIN FLOW VALVE AS POSSIBLE SYSTEM FAILURE UPDATED PUMP ROOM COOLING SYSTEM REVISED SENSOR FAILURE S DETECTION PROBABILITY ADDED DUAL STRAINERS ON PUMP INLET LINE 22
k.
ELECTRIC POWER
\\
\\
\\
S SYSTEM UNAVAILABILITY 4KV EMERGENCY BUS 3/81 4/82 2.9X10-4.7X10-8 MAJOR TREE CHANGES UPDATED FAULT TREE TO INCLUDE:
1.
D/G COOLING FROM ALTERNATE ESW LOOP 2.
DC POWER REQUIRED FOR D/G START 3.
ADDED D/G COOLING SYSTEM EQUIPMENT 4.
REMODELED D/G VENTILATION SYSTEM --
2 LOOPS REQUIRED /DG 5.
REMODELED DC CHARGE LOOPS 2 LOOPS REQUIRED ON DIV. ASB 1 LOOP REQUIRED ON DIV. CSD USED PEACH BOTTOM D/G EXPERIENCE DATA D/G AND OFFSITE POWER RESTORATION BUILT INTO FAULT TREE S
UNAVAILABILITY CHANGE 3/82 4/82 DIESEL GENERATOR' SYSTEM 4.0X10-2.4X10-UNAVAILABILITY D/G FAILURE PROBABILITY 3.2X10-1.7X10-23 l
l
SYSTEM UNAVAILABILITY (LOOP A) 3/81 4/82
-6 2.4X10-7.1X10 0
MAJOR TREE CHANGES ELECTRIC POWER REMOVED FROM ESW TREE -- NOW AT SYSTEM LEVEL ADDED "C" LOOP FOR HPCI SERVICE NSW CHANGED TO 1 PUMP IN STANDBY WITH 2 OPERATING PUMPS ADDED ESW REDUNDANT COOLING WATER DISCHARGE VALVES ADDED FLOW DIVERSION PATHS AS POTENTIAL FAILURE MODES ADDED ESW START SIGNAL FAILURE ESW WET PIT COMMON WITH RHR SW SYSTEM l
4 UNAVAILABILITY CHANGE l
(LOOP A) 3/81 4/82 NSW 3.7X10-2.5X10-l 2.9X10-ESW 1.2X10 l
24 l
FEEDWATER SYSTEM S
SYSTEM UNAVAILABILITY 3/81 4/82 2.9X10' 7.2X10-0 MAJOR TREE CHANGES REMOVED EVENT DEPENDENT FAILURES 1.
OFFSITE POWER 2.
MSIV - CLOSURE & FAILURE TO REOPEN 3.
MA!N TURBINF FAILURES - CONTROL SYSTEM C BYPASS VALVES UPDATED FAULT TREE FEEDWATER SYSTEM AVAILABILITY NOW INPUT TO FEEDWATER EVENT TREES 3/82 4/81 FW FUNCTION 2X10-1.8X10-(TURB. TRIP EVENT TREE) 25 i
6 0
10 OF D
E LIME RICK TOTAL 10 U 19x' AuAevsic P
$ $A l 6 %.'* l s* /.5 W
-4
/
f);yj/
! j A A CLASSI CLASS Il CLASS Ill CLASS IV
$$ OF SS OF HEAT ATWS ATWS 1"A*Jl*'
frOJ"'
^
CONTAINME NT
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i PRELIMINARY OUTLINE OF i
INTRODUCTION 2.
SCOPE OF APPLICANT'S RISK STUDY.
3.
SUCCESS CRITERIA AND ASSUMPTIONS USED 4.
ACCIDENT SEQUENCE MODELING 5.
NUCLEAR SYSTEMS MODELING 6.
DATA BASE AND DISTRIBUTIONS 7.
SYSTEMS UNAVAILABILITY AND ACCIDENT SEQUENCE QUANTIFICATION 8.
CORE MELT MODELING AND PREDICTIONS OF CONTAINMENT FAILURE MODES 9.
OFFSITE CONSEQUENCE ANALYSIS i
10.
UNCERTAINTY AND SENSITIVITY ANALYSES 11.
COMPARISON OF LIMERICK WITH WASH-1400 BWR 12.
CONCLUSIONS AND RECOMMENDATIONS o
REFERENCES o
APPENDICES A.
D. EISENHUT, NRC LETTER TO E. BAUER OF PECO, DATED MAY 6, 1980 B.
DOMINANT ACCIDENT SEQUENCES AND DOMINANT RISK CONTRIBUTORS C.
PREVENTION / MITIGATION FEATURES OF LIMERICK 1
BNL REVIEW 0F LIMERICK PRA PRESENTED BY:
I. A. PAPAZ0GLOU PRESENTED TO:
NRC UTILITY REPRESENTATIVES MAY 14, 1982 BR00XHAVEN NAll0NAL LABORATORY l} g)l
_ A5500ATED UNIVERSITIES, INC. (IIII
OUTLillE OF PRA REVIEW I.
SYSTEf1S ANALYSIS e
ACCIDEllT INITIATORS e
GROUPING ACCORDitlG TO MITIGATING FEATURES e
COMPLETENESS e
FREQUENCIES e
EVEllT TREES e
QUALITATIVE (PLAUSIBILITY, COMPLETENESS SYSTEM SUCCESS CRITERIA) e OUANTITATIVE (SYSTEf1 UNAVAILABILITIES) e FAULT TREES e
QUALITATIVE (COMPLETENESS, DEPENDENCES) e Q U A tlT I T AT IV E (SPOT CHECK)
~
BROOKHAVEN NATIONAL LABORATORY l} g)l ASSOCIATED UNIVERSITIES, INC. (I til
SYSTEMS ANALYSIS (CONT.)
e DATA 8
ASSUMPTIONS, DERIVATIONS, UNCERTAINTIES e
ACCIDENT SEQUENCE QUANTIFICATION e
(CUT SETS OR SYSTEM 'S EQUENCES )
e BINNING OF ACCIDENT SEQUENCES e
EVALUATION OF CLASSIFICATION INTO I4 CLASSES QUALITATIVE AND AUDITING WITH MARCH / CORRAL l
l l
BR00KHAVEN NATIONAL LABORAT0RYl} g)[
A5500ATED UNIVERSITIES, ifK.(llll
CONSEQUENCE ANALYSIS e
CORE MELT PHENOMENOLOGY e
CONTAINMENT TREES e
FAILURE MODES AND PROBABILITIES e
RELEASE CATEGORIES AUDITitlG OF RELEASE FRACTIONS VIA MARCH / CORRAL e
FINAL CONSEQUENCES e
CRAC AtJALYSIS BROOKHAVEN NATIONAL LABORATORY l} g)l ASSOCIATED UNIVERS'ilES, INC(llll
e SENSITIVITY ANALYSIS "t1 ATRIX" APPROACH RISK INDICES VARI ABLFJ e
CORE f1ELT ACCIDENT INITIATORS SYSTEMS e
RELEASE CATEGORIES CORE MELT PHENOMENOLOGY e
FINAL CONSEQUENCES FISSION PRODUCT BEHAVIOR CONTAINMErlT FAILURE MODES METEOROLOGY EVACUATION POPULATION e
UllCERTAINTY PROPAGATI0i!
e IMPUT FR0tl 0 tiler STUDIES BROOKHAVEN NATIONAL LABORATORY l)l)l A5500ATED UNIVERSITIES, INC.(llll
STATUS OF THE REVIEW e
MATRIX FORfiULATI0t1 8
(UP TO RELEASE CATEGORIES) 9
( L I fiE R I C K AS S ES Sf4EflTS )
e RAtlKir1G (CORE T1ELT FREQUEllCY RISK INDEX) e ACCIDENT INITIATORS S
S YS T EtiS (LIMERICK ASSESSMEf1TS)
WILL BE REDONE FOR REV. 3 e
ACCIDEllT ltilTIATORS 9
G R OU P l f1G e
F R EQ UE llc I E S BROOKHAVEN NATIONAL LABORATORY l} g } l ASSOCIATED UNIVERSITIES, INC.(llll s
STATUS OF THE REVIEW (CONT.)
e EVENT TREES 4
CHECK 1NG S
SUCCESS CRITERIA 9
LOSS AND RECOVERY OF ELECTRICAL POWER e
FAULT TREES 9
SOME CONCERNS TAKEN CARE OF BY REV. 3 8
DEPENDENCE MATRICES (FL SS), (SS SS) e BINNING OF SEQUENCES 8
ANALYSIS WI TH MARCH / CORRAL INITIATED BROOKHAVEN NATIONAL LABORATORY l} g)l ASSOCIATED UNIVERSITIES, INC.(I ElI
ACCOMPLISHED MILESTONES OF LIMERICK PRA-REVIEW MAY 06, 1980 NRC LETER FROM D. EISENHUT TO APPLICANT REGARDING RISK EVALUATION OF LIMERICK MAY 21, 1980 MEETING WITH APPLICANT TO DISCUSS' SCOPE AND APPROACH JULY 11, 1980 MEETING WITH APPLICANT TO FURTHER DISCUSS SCOPE OCT. 02, 1980 MEETING WITH APPLICANT TO DISCUSS INTERIM RESULTS MAR. 17, 1981 APPLICANT SUBMITS PRA TO NRC JU!Y 06, 1981 NRC REQUESTED ADDITIONAL INFORMATION REGARDING FAULT TREES AND ASSESSMENT OF PROPERTY DAMAGE SEP. 24, 1981 APPLICANT RESPONSE TO JULY 6 REQUEST FEB 11, 1982 MEETING WITH APPLICANT TO DISCUSS PRA METHODOLOGY MAR. 23, 1982 QUESTIONS SENT TO APPLICANT APR. 30, 1982 PECO SUBMITS REVISED PRA (REV.3)
MAY 13, 1982 NRC STAFF SITE VISIT MAY 14, 1982 MEETING WITH APPLICANT TO DISCUSS PRA REV. 3 l
l
FUTURE MILESTONES IN LIMERICK PRA REVIEW i
PROPOSED MAY 28, 1982 BNL SUBMITS ADDITIONAL QllESTIONS AND ISSUES TO RRAB JUNE 04, 1982 SEND ADDITIONAL QUESTIONS AND ISSUES SENT T0 APPLICANT
- JUNE 11, 1982 APPLICANT'S RESPONSE TO QUESTIONS OF MARCH 23, 1982 JUNE 17, 1982 MEETING WITH APPLICANT TO DISCUSS APPLICANT'S l
RESPONSE AND ISSUES TO THE QUESTIONS OF MARCH 23, 1982 (INCLUDES-COMPUTATIONAL AUDIT)-GE JULY 09, 1982 BNL SUBMITS'EVALUAJION WITH ALL OPE TO RRAB JULY 23, 1982 EVALUATION AND OPEN ITEMS SENT TO APPLICANT AUG. 13, 1982 APPLICANT SUBMITS RESPONSE TO OPEN ITEMS (OR
- SEP 30, 1982 B
11 R
CR REPORT TO RRAB-OCT 15, 1982 MEETING WITH APPLICANT TO DISCUSS NUREG/CR OCT, 29, 1982 BNL SUBMITS FINAL PRA NUREG/CR REPORT TO RRAB
- CONSISTENT WITH EXISTING SCHEDULE SCHEDULE ASSUMES NO CHANGE IN SCOPE OF CURRENT PRA