ML18153C794
| ML18153C794 | |
| Person / Time | |
|---|---|
| Site: | Surry  |
| Issue date: | 10/23/1991 |
| From: | Berkow H Office of Nuclear Reactor Regulation |
| To: | Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 9110310050 | |
| Download: ML18153C794 (45) | |
Text
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.r Docket Nos. 50-280 and 50-281 e
October 23, 1991 LICENSEE: Virginia Electric and Power Company (VEPCO)
FACILITY: Surry Units 1&2
SUBJECT:
SUMMARY
OF MEETING WITH VEPCO ON OCTOBER 9, 1991 REGARDING INDIVIDUAL PLANT EXAMINATION (IPE) INTERNAL FLOODING ANALYSIS A meeting was held in Rockville, Maryland on October 9, 1991 to discuss and obtain additional information on the licensee's internal flooding analysis portion of their IPE.
c2re damage frequency from internal floods was calculated to be l.lXlO-per year. is a list of meeting attendees. The licensee's presentation included a description of the internal flooding models and analyses, the modifications and actions made and taken to date to minimize the flooding vulnerability, a discussion of the plant configuration, and operating practices relevant to the flooding issue and plans for future improvements to reduce the core damage frequency due to internal flooding.
A copy of the presentation slides is included as Enclosure 2.
Enclosures:
- 1. List of Attendees
- 2.
Presentation Slides cc w/enclosures:
See next page Distribution See next page
/s/
Herbert N. Berkow, Director Project Directorate II-2 Division of Reactor Projects - I/II Office of Nuclear Reactor Regulation I
OFC
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SUMMARY
10/9/91 Qr-0 ~
9110310050 911023
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NRC VEPCO MEETING ON ATTENDEES Herbert Berkow Frank Congel Paul Guymer Dave Bucheit R. M. Berryman J. A. Price D. A. Sommers M. L. Bowling F. K. Moore J. D. Rubin W. Beckner S. Long Michael Bohn John Schiffgens J. H. Flack A. Ramey-Smith Erasmia Lois Mark Cunningham John T. Chen T. M. Su Helen Pastis SURRY IPE October 9, 1991 Jeff Schackelford John Lambright S. Varga Kazimieras M. Campa Jake Wechselberger Gus Laina~
Charles Ader Ed Chow Bill Gleaves Robert E. DePriest Jon Johnson Jake Zimmerman Ron Hernan Louis Wheeler Leon Engle e
ENCLOSURE 1 ORGANIZATION NRC/NRR NRC/NRR NUS VEPCO VEPCO VEPCO VEPCO VEPCO VEPCO NRC/RII NRC/NRR NRC/NRR Sandia Nat'l Labs NR.C/NRR/RAB
~JRC/RES/SAIB NRC/RES/PRAB NRC/RES/PRAB NRC/RES/PRAB NRC/RES/SAIB NRC/RES/RPSIB NRC/NRR NRC/RII Sandia Nat'l Labs NRR/DRPE NRR/DREP/PRAB OEDO NRR/AD RII Reactors NRR/RES/SAIB NRC/RES/DSIR/SAIB RES/EMEB NRC/SAIB NRC/RII NRC/RES/DSIR/EIB NRC/NRR/DRPE NRC/RES/SAIB NRC/NRR/DRPE
--1
( j Virginia Electric and Power Company cc:
Michael W. Maupin, Esq.
Hunton and Williams Post Office Box 1535 Richmond, Virginia 23212 Mr. ~ichael R. Kansler, Manager Surry Power Station Post Office Box 315 Surry, Virginia 23883 Senior Resident Inspector Surry Power Station U.S. Nuclear Regulatory Commission Post Office Box 166, Route 1 Surry, Virginia. 23883 Mr. Sherlock Holmes, Chairman Board of Supervisors of Surry County Surry County Courtr.ouse Surry, Virginia 236E3 Dr. W. T. Lough Virginia State Corporation Commission Division of Energy Regulation Post Office Box 1197 Richmond, Virginia 23209 Regional Administrator, Region II U.S. Nuclear Regulatory Commission 101 MariEtta Street N.W., Suite 2900 Atl2r.ta, Georgia 30323 C. M. G. Buttery, M.D., M.P.H.
State Health Commission Office of the Commissioner Virginia Department of Health P.O. Box 2448 Richmond, Virginia 23218 e
Surry Power Station Attorney General Supreme Court Building 101 North 8th Street Richmond, Virginia 23219 Mr. E. Wayne Harrell Vice President - Nuclear Operations Virginia Electric and Power Company 5000 Dominion Blvd.
Glen Allen, Virginia 23060 Mr. J.P. O'Hanlon Vice President - Nuclear Services Virginia Electric and Power Company 5000 Dominion Blvd.
Glen Allen, Virginia 23060 Mr. Martin Bowling
~anager - Nuclear Licensing Virginia Electric and Power Company 5000 Dominion Blvd.
Glen Allen, Virginia 23060 Mr. W. L. Stewart Senior Vice President - Nuclear Virginia Electric and Power Cor.ipany 5000 Dominion Blvd.
Glen Allen, Virginia 23060
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Meeting Summary Dated October 23, 1991 Distribution Docket-File NRC & Local PDRs T. Murley/F. Miraglia J. Partlow S. Varga G. Lainas H. Berkow B. Buckley L. Engle F. Congel, 10-E-2 S. Rubin, RII W. Beckner, 10-E-4 S. Long, 10-E-4 J. Schiffgens, 10-E-4 J. Flack, NLS/324 A. Ramey-Smith, NLN/316 E. Lois, NLN/316 M. Cunningham, NLS/372 J. Chen, NLS/324 T. Su, NLS/314 J. Zimmerman, NLS/372 L. Wheeler, NLS/372 R. Hernan H. Pastis, 12-E-4 J. Shackelford, RII J.,Johnson, RI I S. Varga K. Campe, 10-E-4 G. Lainas C. Ader, NLS/324 E. Chow, NLS/324 B. Gleaves, NS2/17B ACRS (10)
OGC J. Weschelberger, 17-G-21 D. Mi 11 er E. Jordan, MNBB 3701 M
- S i n ku l e, R II
SURRY IPE / INTERNAL FLOODING ANAL VSIS OCTOBER 9, 19*91 VIRGINIA POWER
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INTRODUCTION e
VIRGINIA POWER F. K. MOORE VICE PRESIDENT - NUCLEAR ENGINEERING SERVICES
AGENDA
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INTRODUCTION IPE / INTERNAL EVENTS RESULTS IPE / INTERNAL FLOODING ANAL VSIS
- *MODIFICATIONS TO ELIMINATE INTERNAL FLOODING VULNERABILITY CURRENT PLANT CONFIGURATION AND OPERA TING PRACTICES FUTURE PLANS AND CONCLUSIONS F. K. MOORE R.M.BERRYMAN D. M. BUCHEIT R.M.BERRYMAN J. A. PRICE M. L. BOWLING
IPE INTERNAL EVENTS RESULTS VIRGINIA !POWER R.M.BERRVMAN MANAGER - NUCLEAR ANAL VSIS & FUEL
INDIVIDUAL PLANT EXAMINATION SURRY UNITS 1 AND 2 SURRY IPE PERFORMED IN ACCORDANCE WITH NRC GENERIC LETTER
~~.
METHOD OF EXAMINATION INCLUDED DEVELOPMENT OF LEVEL 1 AND LEVEL 2 PRA MODELS FOR EACH SURRY UNIT IPE PERFORMED BY A PROJECT TEAM CONSISTING OF VIRGINIA POWER AND NUS CORPORATION ANALYSTS AN INDEPENDENT REVIEW OF THE PRA MODEL AND RESULTS WAS PERFORMED BY QUALIFIED PERSONNEL FROM VIRGINIA POWER, SCIENCE APPLICATIONS INCORPORATED, AND STONE AND WEBSTER
.ENGINEERING CORPORATION EXAMINATION WAS COMPREHENSIVE AND PROVIDED SIGNIFICANT.
INSIGHT REGARDING POSSIBLE CORE DAMAGE SEQUENCES, POTENTIAL MITIGATIVE ACTION, AND ENHANCEMENTS TO REDUCE RISK
- THE 'TOTAL CORE DAMAGE FREQUENCY FROM INTERNAL EVENTS DERIVED FROM THE SURRY IPE WAS COMPARABLE TO THAT DOCUMENTED IN NUREG/CR-4550
- SURRY IPE REVEAL~D VULNERABILITY TO INTERNAL FLOODS
(
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COMPARISON OF RESULTS AND DEVIATIONS BE1WEEN SURRY IPE AND NUREG/CR-4550 NUREG/*
Surry!PE*
CR:4550 Deyjation
- Total CD Frequency from 7.4E-5 3.3E-5
+4.1E-5 lntemaJ Events New Sequences in IPE:
ESR Cooling 2.1E.;s CD Freq. with Comparable Scope 5.3E-5 3.3E-5
+2.0E-5 Effect of Success Criteria Need for Recirc Spray
+3.4E-6 Small Break Partition/Freq.
+1.1E-5 AHR after SG Tube Rupt.
+2,9E:6 TOTAL 1.7E-5 CD with Comparable Success Criteria and Scope 3.SE-5 3.3E-5 Most Sizable Changes Station Blackout
-1.3E-5 SGTR
-1.4E-6 All other sequences
+3.4E-6
. CD from lntemaJ Floods 1.1E-3
+1.1E-3
- Point estimate frequencies
IPE INTERNAL.FLOODING ANALYSIS VIRIGINIA POWER D. M. BUCHEIT SENIOR STAFF. ENGINEER
- NUCLEAR ANALYSIS & FUEL I
INTERNAL FLOOD ANAL VSIS BASIC ANALYTICAL STEPS DIVIDE PLANT INTO INDEPENDENT FLOOD AREAS IDENTiFY MAJOR FLOOD SOURCIES IDENT~FY POTENTIAL INTER AREA PROPAGATION PATHWAYS SCREEN FLOOD AREAS AND POTENTIAL FLOOD PATHWAYS USING CONSERVATIVE ANALYSES PERFORM REALISTIC (DETAILED) ANALYSIS OF POTENTIAL SIGNIFICANT FLOOD AREAS, SOURCES, AND SCENARIOS l
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INTERNAL FLOOD ANALYSIS
{ continued)
- . FLOOD ANALYSIS ACCOUNTS FOR:
FREQUENCY/SIZE OF FLOOD EVIENT FLOOD MITIGATION MEASURES (AUTO ISOLATION, DRAINS, SUMP PUMPS, FLOOD ALARMS, AND PROCEDURES)
RESULTING NATURE OF FLOOD INITIATED TRANSIENT AND EQUIPMENT DAMAGE.
COINCIDENT RANDOM EQUIPMENT FAILURES AND HUMAN ERRORS RECOVERY ACTIONS f
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RES UL' 1 ~S OF INTERNAL FLOOD ANALYSIS FOR BASE CASE 18 FLOOD*AREAS.IDENTIFIED AND SCREENED AT SURRY POWER STATION 6 OF THE 18 FLOOD AREAS EVALUATED IN DETAIL BASE CASE RESULTS FLOOD AREA FLOOD SOURCE CDF/YR (BASE CASE)
. UNIT 1 TURBINE BUILDING (CW + SW)
UNIT 2 TURB~NE BUILDING (CW + SW)
UNIT 1 SAFEGUARDS BUILDING (RWST SUPPL V)
MECHANICAL EQUIPMENT (SW)
ROOM NO. 3 AUXILIARY BUILDING (RWST SUPPL V),
UNIT 2 SAFEGUARDS BUILDING (RWST SUPPL V)
- S.9 E-4 4.5 E-4 3.1 E-5 3.0 E-5 2.3 E-5 1.5 E-5 1.1 E-3 l
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SIMPLIFIED PLANT LAYOUT DRAWING SHOWING FLOOD AREA BOUNDARIES 11£ACTIR OlfJA llllNJ mn,
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SEIN ICC III ILD II<<: *
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TransfomKn Turbine Building Main Condenser Condenser Pits Service Building Auxlllary Building Primary Water Storage Tank I
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EL2~L _______ ~ ______ J SURRY NUCLEAR POWER PLANT CROSS SECTIONAL VIEW Dlllcharge Dllch Seal C8nal Weir e
EVALUATION OF TURBINE BUILDING MOST SIGNIFICA.NT FLOOD INITIATORS CIRCULATING WATER AND SERVICE WATER FAILURES VALVE BODIES EXPANSION JOINTS PIPE/CONDENSER SOURCES GRAVITY FED FROM INTAKE CANAL TWO FLOOD TYPES DEFINED LONG TERM ISOLABLE ~ CAN ONLY BE ISOLATED BY STOP LOGS (ASSUMED TO TAKE UP TO 24 HOURS)
SHORT TERM ISOLABLE - CAN BE ISOLATED BY CLOSING VALVES OR BY INSTALLING STOP LOGS I
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Turbine Building Basement Plan Auxlllary Building ESGR
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EVALUATION OF FLOOD HAZARD FOR CW AND SW SYSTEMS EXTENSIVE SEARCH OF HISTORICAL INDUSTRY FLOODING DATA ASSOCIATED WITH CW AND SW SYSTEMS DATA IS LIMITED AND NOT WELL DOCUMENTED PERMITTED GENERAL LOG-LINEAR RELATIONSHIP BETWEEN FLOOD FREQUENCY AND RATES FOR ALL CW AND SW FLOODING SOURCES RELATIONSHIP NOT NECESSARIL V APPLICABLE TO INDIVIDUAL
- FLOOD SOURCES METHOD USEFUL FOR RELATIVE RANKING OF POTENTIAL FLOOD HAZARDS BUT NOT ABSOLUTE VALUE DETERMINATION QUANTIFICATION OF LOG-LINEAR RELATIONSHIP RELIES ON ENGINEERING JUDGEMENT TO ASSIGN:
MAXIMUM POSSIBLE FLOW AREA/RATE FOR ANY GIVEN SOURCE FREQUENCY OF EXCEEDING ONE PARTICULAR FLOW RATE WITHIN THE POSSIBLE RANGE (USUALLY AT LOWER END)
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EVALUATION OF FLOOD HAZARD FOR CW AND SW SYSTEMS (continued)
USE OF LOG-LINEAR RELATIONSHIP TO DETERMINE PROBABILITY OF COMPONENT FAILURES RESULTING IN MAXIMUM FLOOD RATES IS CONSERVATIVE REVIEW OF INDUSTRY FLOODING DATA APPLICABLE TO SURRY GENERALLY INDICATES ONL V SMALL COMPONENT FLOW RATES HAVE BEEN EXPERIENCED (EXAMPLE-SW EXPANSION JOINTS)
EXTRAPOLATION OF DATA TO HIGHER THEORETICAL FLOW
- RATES USING THIS METHOD RESULTS IN CONSERVATIVE UTILIZATION OF LIMITED COMPONENT FAILURE DATA RESULTING CORE DAMAGE FREQUENCY DUE TO FLOODS IS THEREFORE CONSERVATIVE (COMPARED TO IPE INTERNAL EVENTS ANALYSIS)
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SERVICE WATER SYSTEM FLOODING RATES FROM ACTUAL EVENTS J.5 J
2.5 2
1.5 I
I 3
5 7
9 II ll 15 17 EVENT NUMBER
EVALUATION OF FLOOD HAZARD FOR CW AND SW SYSTEMS
{continued)
BASIC STEPS
- 1)
. SEARCH OF HISTORICAL INDUSTRY EVENTS LED TO CONCLUSION THAT FLOOD HAZARD CAN BE REPRESENTED BY FLOOD HAZARD EQUATION:
- 2)
P = F/N = A + B LOG Q P = PROBABILITY PER COMPONENT YEAR OF EXCEEDING FLOOD RATE,Q N = NllMBER OF COMPONENT YEARS OF EXPERIENCE F = FREQUENCY OF EVENTS EXCEEDING FLOOD RATE, Q.
'A' AND 'B' ARE CONSTANTS FOR.A PARTICULAR FLOOD SOURCE.
'B' IS A NEGATIVE CONSTANl DETERMINATION OF 'A' AND 'B' CONSTANTS FOR EACH SOURCE BASED ON FLOODING DATA AND SPS SPECIFIC CHARACTERISTICS
- 3)
SUMMATION OF ALL CONTRIBUTORS TO A PARTICULAR FLOOD CATEGORY r
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EVALUATION OF FLOOD HAZARD FOR CW AND SW SYSTEMS
{continued)
EXAMPLE - CW EXPANSION JOINT RUPTURE
- . HISTORICAL INDUSTRY DATA COMPONENT YEARS (N): 1.4 E4 ASSUMED 2 EVENTS AT 2,000 GPM EACH APPLICABLE FOR SURRY BASED ON REVIEW OF FOLLOWING EVENTS EVENT FLOW RATE MECHANISM APPLICABILITY QUAD CITIES (6n2) 15,000 GPM HYDR. VALVE CLOSES NO LaSALLE (5/85) 2,000 GPM MOUNTING BOLT FAILS YES VANDELOS (10/89)
UNKNOWN FIRE NO FORT ST. VRAIN (4/88) 15,000 GPM AGING PARTIALLY I
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I e EVALUATION OF FLOOD HAZARD FOR CW AND SW SYSTEMS (continued)
MAXIMUM FLOW RATE BASED ON MAXIMUM FLOW AREA OF CIRCUMFERENCE X 1/2 EXPANSION JOINT LENGTH 169,114 GPM FOR CW INLET EXPANSION JOINT USING ABOVE DATA DETERMINE 'A' AND 'B' CONSTANTS TO SOLVE FLOOD DAMAGE EQUATION FOR CW INLET EXPANSION JOINT.
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CW. Expansion Joint Log Linear Curve 1000000 :::::::::::::::::::::::::::::::::::::::::::::::::***********-*****-*------****-***-*--*---
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5.0E-05 1.0E-04 1.SE-04 2.0E-04 2.SE-04 Probability Per Component Year
DETAILED EVALUATION OF TURBINE BUILDING STAGES IN FLOOD SCENARIO CUMULATIVE FLOOD VOLUME REQUIRED CONDENSER INLET/SW VALVE PIT RAPIDLY FILLS, INITIATING FLOOD ALARM ALL TURBINE BUILDING PITS FILL SUMP PUMPS START AUTOMATICALLY ON HIGH SUMP LEVEL FLOOD LEVEL IN TB REACHES ELEVATION 10'2" GROUNDING MCCs. SUMP PUMPS DISABLED FLOOD LEVEL ~N TB REACHES ELEVATION 10'3" INITIATING AUTO CLOS.URE OF CW INLET VALVES FLOOD LEVEL IN TB REACHES ELEVATION 11 '0" DISABLING CW.
INLETMOVs FLOOD LEVEL IN TB REACHES ELEVATION 11 '6" OVERFLOWING DIKES. ALL SW VALVES IN PITS DISABLED AND WATER ENTERING ESG ROOM AND AUXILIARY BUILDING (FDS 1 TB3)
FLOOD LEVEL 1.N ESG ROOM REACHES ELEVATION 9'10" DISABLING ALL4.16 KV AND 480 V AC POWER (FDS 1TB5)
FLOOD LEVEL IN AUXILIARY BUILDING REACHES ELEVATION 3'6" DISABLING CCW AND CHARGING PUMPS DUE TO BACK FLOW THROUGH DRAiNS (FDS 1TB4) 520,000 GAL 666,000 GAL
- 1,248,000 GAL
-1,400,000 GAL
-1,400,000 GAL e
FREQUENCY OF LONG TERM ISOLABLE FLOODING I
C~TEGORIES FROM CW SYSTEM, UNIT 1 OR-2 CA,.EGORY CATEGORY 1 (3600 <FLOW< 190022 GPM)
- ESG !ROOM* FLOODED RUPTURE OF ONE OF FOUR CONDENSER INLET VALVES RUPTURE OF INLET PIPE TOTAL FREQUENCY FOR CATEGORY 1 =
FREQUENCY/VEAR 1.9 E-4 3.2 E-5 2.3 E-4 CATEGORY 2 (3569 <FLOW< 3600 GPM)
- SW VALVE PITS FLOODED RUPTURE OF ONE OF FOUR CONDENSER INLET VALVES RUPTURE-OF CONDENSER*INLET PIPE TOTAL FREQUENCY FOR CATEGORY 2 =
4.2 E-7.
6.9 E-8 4.8 E-7
FREQUENCY OF SHORT TERM ISOLABLE FLOODING CATEGORIES FROM CW SYSTEM, UNIT 1 OR 2 CATEGORY CATEGORY 1 (97000 < FLOW < 139537 GPM)
GROSS !RUPTURE OF ONE OF FOUR CONDENSER OUTLET VALVES GROSS RUPTURE OF CW OUTLET PIPES TOTAL FREQUENCY FOR CATEGORY 1 =
CATEGORY 2 (56000 <FLOW< 97000 GPM)
SEVERE RUPTURE OF ONE OF FOUR CONDENSER OUTLET VALVES GROSS RUPTURE OF CONDENSER WATER BOX SEVERE RUPTURE OF CW OUTLET PIPES TOTAL FREQUENCY FOR CATEGORY 2 =
FREQUENCY/VEAR.
1.8 E-5 3.3 E-5 3.5 E-5 3.2 E-5 2.0E-4
- 4.2E-5 2.BE-4
- ~
I,
FREQUENCY OF SHORT TERM ISOLABLE FLOODING CATEGORIES FROM CW SYSTEM, UNIT 1 OR 2
~
1 (continued) e CATEGORY CATEGORY 3 (16000 c FLOW< 56000 GPM)
MODERATE RUPTURE OF ONE OF FOUR CONDENSER OUTLET VALVES MODERATE RUPTURE OF CW CONDENSER OUTLET PIPES SEVERE RUPTURE OF CONDENSER WATER BOX TOTAL FREQUENCY FOR CATEGORY 3 =
FREQUENCY/YEAR 7.4 E-5 9.6 E-5
. 1.1 E-4 1.3 E-3
FREQUENCY OF SHORT TERM ISOLABLE FLOODING CATEGORIES FROM CW SYSTEM, UNIT 1 OR 2 (continued)
CATEGORY CATEGORY 4 (3569 <FLOW< 16000 GPM)
FREQUENCY/YEAR RUPTURE OF ANY SHIELDED EXPANSION JOINT IN 6.0 E-4 CONDENSER INLET OR OUTLET PIPES LEAST SEVERE RUPTURE OF CONDENSER OUTLET VALVES 8.8 E-5 MODERATE RUPTURE OF CONDENSER WATER BOX
- LEAST SEVERE Rv?TURE OF CW OUTLET PIPES TOTAL FREQUENCY FOR CATEGORY 4 =
1.3 E-3 1.2 E-4 2.1 E-3 el
Unft 1 CW Floods fn Turbine Bldg.
(short term isolable) 3.5E*05 139537 gpn (cat 1) 2.8E*4 97000 gpm (cat 2) 1.3E*3 56000 1P111 (cat 3) 2.1E*3 16000 gpm (cat 4)
WLOOD DAKAGB BVBHT 'l'RBB POR UBIT 1
.TURBID BUILDING SHORT TBRM ISOLABLB CW PLOODS Failure of cw Inlet Failure to close CW Failure to close CW valve to close before inlet valve manually Inlet valve before Turbine Bldg. level (using hand crank)
Aux. Bldg. flooded reaches 11 1011 before lvl reaches 11 1611 ESGR flooded I-7.3x10*3 1.0 1.0 I 7.3x10*3 1.0 1.0 7.3x10"3 1.0 1.0 I 7.3x10*3 I
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= 0.895
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State (FDS)
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0 1TB5*
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IUAAY INDIVIDUAL PUNl EXANINAVION PAA PITIIS IUI llfll I fll91.. a,ILDIIIO CII &
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CONSERVATISMS IN FLOODING ANALYSIS ASSUMPTIONS ENTRANCE FROM TURBINE BUILDING TO ESG ROOM ASSUMED TO BE OPENED LOWEST ELEVATION USED FOR ALL MCCs IN SAME AREA TO DETERMINE CRITICAL FLOOD HEIGHT CONSERVATIVE MINIMUM NUMBER OF SUMP PUMPS AVAILABLE e
(2 OUT OF 9 PUMPS) tt STOP LOGS NOT INSERTED FOR 24 HOURS
CONSERVATISMS IN FLOODING ANAL VSIS (continued)
ESTIMATION OF FLOOD HAZARD NO MAJOR FLOODING EVENTS FOR SW VALVES/EXPANSION JOINTS AND CW INLET VALVES APPLICABLE TO SURRY FLOOD FREQUENCY AT LOWER END OF RANGE CONSERVATIVELY ASSIGNED (E.G., HISTORICAL LEAKAGE FROM EXPANSION JOINTS APPROXIMATELY 1 GPM; ANALYSIS CONSERVATIVELY ASSIGNED ONE EVENT AT 100 GPM)
CATEGORIZATION OF FLOOD HAZARDS - LARGEST CATEGORY FLOW RATE USED TO DETERMINE HUMAN ERROR PROBABILITIES
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MODIFICATIONS TO ELIMINATE THE INTERNAL FLOODING VULNERABILITY
. VIRGINIA POWER R.M.BERRYMAN MANAGER - NUCLEAR ANAL VSIS & FUEL t
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CASE BASE 1
3A 4
12 PLANNED MODS PLANNED MODIFICATIONS TO ELIMINATE INTERNAL FLOODING VULNERABILITY DESCRIPTION
- ENHANCED FLOOD MITIGATION! PROCEDURES
- PERIODIC INSPECTION OF EJs
- PERIODIC EJ REPLACEMENT
- OPERATOR TO VALVE BOLT INSPECTION
- INSPECT MOY/OPERATOR CONNECTING PINS
- CASE 1 ENHANCED MAINTENANCE PROGRAM
- SUBMERSIBLE MOTOR OPERATORS FOR BC/CC/SW MOVs
- CASE 1 ENHANCED MAINTENANCE PROGRAM
- CASE 1 ENHANCED MAINTENANCE PROGRAM*
- BACKFLOW PREVENTION IN CHP DRAIN LINES
- CASE 1 ENHANCED MAINTENANCE PROGRAM
.. BACKFLOW PREVENTION IN CHP DRAIN LINES
- SUBMERSIBLE MOTOR OPERATORS CDF 1.1 E-3 2.0 E-4 1.8 E-4 1.7 E-4 1.6 E-4 9.9 E-5
CURRENT PLANT CONFIGURATION AND OPERATING PRACTICES VIRGINIA POWER J. A. PRICE ASSISTANT STATION MANAGER-NUCLEAR SAFETY & LICENSING
CURRENT PLANT FLOOD CONTROL MEASURES
- ADMINISTRI-.TIVE /MAINTENANCE /PROCEDURES ABNORMAL AND ANNUNCIATOR RESPONSE PROCEDURES UPDATED FOR IPE ANALYSIS' ANNUAL PM PROCEDURES FOR FLOOD PROTECTION DEVICES REFUELING PROCEDURES FOFJ TESTING FLOOD PROTECTION AND ALARM SYSTEMS EWR APPROVED, AWAITING IMPLEMENTATION TO IMPROVE.
FLOOD CONTROL PANEL AND ENHANCE ANNUNCIATION
CURRENT PLANT FLOOD CONTROL MEASURES *
- ADMINISTRATIVE/MAINTENANCE/PROCEDURES
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(continued)
- e.
MAINTENANCE PROGRAMS INCLUDE TAGOUT CONTROLS AND INDEPENDENT VERIFICATION FOR RETURN TO SERVICE LIMITS IMPOSED ON CW/SW VALVE LEAKAGE DOUBLE ISOLATION UTILIZED FOR REFUELING MAINTENANCE ACTIVITIES -
- tt IMP.LEMENT ADDITIONAL ADMINISTRATIVE REQUIREMENTS FOR NON-OUTAGE CW/SW WORK I
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I CURRENT PLANT FLOOD CONTROL MEASURES -
STOP LOG CONFIGURATION CONTROLS e,
FOUR SETS OF STOP LOGS STORED AT THE HIGH LEVEL INTAKE ST~~UCTURES THREE CRANES.AVAILABLE ONSITE CAPABLE OF INSTALLING STOP LOGS APPIROXIMATEL Y 1 TO 3.5 HOURS TO INSTALL (NO FLOW CONDITIONS)
INSTALLED VIA WORK ORDER PROCESS - TAGOUT BY EXISTING PROCEDURES
CURRENT PLANT FLOOD CONTROL MEASURES
- STATUS OF EQUIPMENT EXPANSION JOINTS OF MAJOR IPE SIGNIFICANCE
- REPLACED DURING CW VALVE REPLACEMENT IN 1988 OUTAGES OCTOBER 1991 - SATISFACTORY INSPECTION OF CW/SW BOLTED CONNECTIONS ON VALVES, EXPANSION JOINTS, AND FLOOD PROTECTION DEVICES
- MINOR SURFACE CORROSION
- NO SIGNIFICANT DEGRADATION NOTED TURBINE BUILDING SUMP PUMPS RELIABLE f "t; I
- "r FUTURE ACTIONS AND CONCLUSIONS VIRGINIA POWER M. L. BOWLING MANAGER
- NUCLEAR LICENSING & PROGRAMS
CONCLUSIONS-IPE RESULTS INDICATE VULNERABILITY TO UNISOLABLE INTERNAL FLOODS SHOULD THEY OCCUR PROBABILITY OF OCCURRENCE IS NOT DIRECTLY QUANTIFIABLE BASED ON ACTUAL OPERATING EXPERIENCE, RATHER IT IS THEORETICALLY DERIVED FROM LIMITED AVAILABLE COMPONENT FAILURE DATA AND CONSERVATIVE MODELING ASSUMPTIONS ACTUAL PROBABILITY OF OCCURRENCE IS ACCEPTABLY LOW
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BECAUSE CRITICAL COMPONENTS, WHICH WILL PREVENT a
INTERNAl FLOODING, ARE BEING MAINTAINED THROUGH EXISTING MAINTENANCE PROGRAMS. ADDITIONALLY, SUMP PUMPS ARE RELIABLE PROCEDURE, PROGRAM, AND EQUIPMENT ENHANCEMENTS HAVE BEEN SCHEDULED TO REDUCE BOTH PROBABILITY OF AND ELIMh 1~ATE VULNERABILITY*TO INTERNAL FLOODING
PLANS AND SCHEDULES. FOR REDUCING INTERNAL FLOODING CORE DAMAGE FREQUENCY ACTIVITY COMPLETION ESTIMATED DATES CDF.*
PROCEDURAL REVISIONS AND SUMP CURRENT
< 8 E-4 PUMP RELIABILITY
. INSPECTIONS, MAINTENANCE DURING 4/26/93
<2 E-4 OUTAGES, AND CHARGING PUMP DRAIN LINE BACKFLOW PREVENTION DEVICES J
PHYSICAL PLANT MODIFICATIONS AND*
12/31/95 9.9 E-5 FULL MAINTENANCE PROGRAM IMPLEMENTATION.
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