ML20141N552
| ML20141N552 | |
| Person / Time | |
|---|---|
| Issue date: | 02/25/1986 |
| From: | Paulson W Office of Nuclear Reactor Regulation |
| To: | Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 8603170057 | |
| Download: ML20141N552 (33) | |
Text
. - _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ -.
'T o'
F;bruary 25, 1986 OM 8 o / 6 w
LICENSEE: B&W Owners Group Availability' Committee
SUBJECT:
SUMMARY
OF DECEMBER 12, 1985 MEETING TO DISCUSS REACTOR TRIP SYSTEM TEST INTERVAL EXTENSION The staff met with the B&W Owners Group (B&WOG) Availability Committee in Bethesda, Maryland on December 12, 1985. The purpose of the meeting was to discuss the B&WOG program to support an extension of the test interval for the reactor trip system. Enclosure 1 is a list of attendees. The handouts for the meeting are also enclosed (Enclosure 2).
The B&WOG indicated that about 0.5 trip / plant / year is attributable to reactor trip system testing. About 0.25 trip / plant / year is attributable to sensor string testing which is conducted monthly. The B&WOG analysis indicates that the spurious trips attributable to sensor string testing could be reduced by about 75% if the test interval was increased to 4 months. The reduction of spurious trips is the major quantifiable benefit of reduced testing.. The B&WOG plans to submit a report for NRC review and approval.
1M TD F Wa ter A.
au son, project Manager PWR Project Directorate #6 Division of PWR Licensing-B
Enclosures:
As Stated cc w/ enclosures:
See next page f
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MEETING
SUMMARY
DiFTRIBUTION i.
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LIST OF ATTENDEES OF B&WOG MEETING HELD ON DECEMBER 12, 1985 Name Affiliation Telephone Number Guy Vissing NRC/PWR-B 301-492-8796 Walt Paulson NRC/PWR-B 301-492-8153 Courtney Smyth GPU Nuclear (TMI-1) 717-948-8551 James'Langenbach GPUNuclear(Parsippany) 201-299-2151 Leo Kolonay B&W 804-385-2021 Moni.De NRC/ACRS 202-634-3284 Olan Parr NRC/PWR-B 301-492-7632 Dennis Crutchfield NRC/PWR-B 301-492-7733 Bob Enzinna B&W 804-385-0418 Bob Wichert B&WOG 209-333-2935(x4373) i Eric Swanson B&W 804-385-2620 Faust Rora NRC/PWR-A 301-492-7831 I. Ahmed NRC/PWR-B 301-492-8941' Don Lasher NRC/PWR-A 301-492-7200 c.
9
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t B&WOG AVAILABILITY COMMITTEE RTS TEST INTERVAL - EXTENSIO!'
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BWOG TECHNICAL SPECIFICATION ACTIVITIES O
CONCENTRATING ON REVAMPING TECHNICAL SPECIFICATIONS (TECHNICAL SPECIFICATION COMMITTEE)
O.
MAINTAINING COGNIZANCE OF NRC PETS PROGRAM ACTIVITIES (TECHNICAL SPECIFICATION COMMITTEE)
O PERFORMING EVALUATION OF RTS STI'S (AVAILABILITY COMMITTEE) 4
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PURPOSE OF MEETING
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- PRESENT METHODS AND FINDINGS TO DATE
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- B&WOG OBJECTIVES OBTAIN EXTENSION OF TEST INTERVAL FOR SENSOR STRINGS OF THE RTS OBTAIN NRC CONCURRENCE WITH METHODOLOGY FOR FUTURE APPLICATIONS TO OTHER SYSTEMS e
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S EXPECTED BENEFITS OF THE RTS PROGRAM O
ESTABLISH A RATIONAL' BASIS FOR EVALUATING TECHNICAL SPECIFICATIONS O
SAFETY IMPROVEMENT DUE TO RTS STI EXTENSION ELIMINATE CHALLENGES TO OPERATORS ELIMINATE CHALLENGES TO TECHNICIANS ELIMINATE. CHALLENGES TO SAFETY SYSTEMS 6
4
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RTS TEST INTERVAL EXTENSION OVERVIEW I
CALCULATION OF RTS RELIABILITY AT ggg gy VARI 0tlS TEST PRA EVALUATION ASSESS TO DETERMINE RCSULTS AND
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NET CHANGE OF DOCUMENT IN CORE MELT REPORT TO CALCULATION OF FREQUENCY NRC SPURIOUS TRIPS DUE i
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~ 0.25 TRIPS PER. YEAR DUE TO SENSOR STRING - aSTING (MONTHLY)
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Figure 2-7
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MISSION SUCCESS POWER IS REMOVED FROM ALL SAFEW AND REGUIATING ROD GROUPS MISSION SUCCESS CRITERION IS:
O CONSERVATIVE FOR ATWS O
APPROPRIATE FOR EVALUATING TECH SPECS O
PENALIZES OCONEE CONFIGURATION - REQUIRES SAFETY AND REGUIATING RODS TO BE INSERTED OPERATOR MANUAL TRIP - NOT INCLUDED ICS ROD. DRIVE IN - NOT INCLUDED 8
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P" e
e HIGHLIGHTS OF EVALUATION DYNAMIC MODELING
- CONFIGURATION CHANGES DURING TESTING
. DATA FROM OPERATING EXPERIENCE
- CMF TIME DEPENDENCIES ACCOUNTED FOR STAGGERED TESTING TEST OUTAGE WEAROUT f
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MODELING IDSS OF FEEDNATER TRANSIENT SELECTED
- A RELATIVELY FREQUENT EVENT
- NOST SEVERE ATWS PRESSURE CONDITION
- GOOD REPRESENTATIVE TRANSIENT FOR TRIP CONCERNS
- SENSORS FOR THIS TRANSIENT MFP TRIP (ARTS DIGITAL SWITCHES)
- RC PRESSURE HIGH
- RC TEMPERATURE HIGH
- ALL OTHER RTS COMPONENTS ARE THE SAME FOR ALL TRAllSIENTS
- SENSORS FOR OTHER TRANSIENTS CAN BE DIFFERENT
- ALL SENSORS AND STRINGS AVAILABILITIES HAVE BEEN EVAI.UATED
- THE IDSS OF FEEDWATER TRANSIENT AIO ITS SENSORS AND STRINGS PROVIDE REASONABLE ASSURANCE THAT OTHER POSSIBLE TRANSYENTS ARE B10NDED l
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- EFFECTS OF CHANGES IN SYSTEM CONFIGURATION FOR TESTING AE MAINTENANCE (CHANNEL BYPASSED)
- CAN DEMONSTRATE THE EFFECTS OF STAGGERING
- ALLONS TIME DEPENDENT FAILURE RATES TO BE USED (NO:4 AVAILABLE)
- RESULTS
- AVERAGE UNhVAILABILITY OVER A TIME INTERVAL
- INSTANTANEOUS FAILURE PROBAB.. 'ITY (NITH TIME AND FOR CHANGES OF CONFIGURATION FOR TESTING) l i
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U
i DATA
- PREFERRED OPERATING EXPERIENCE TO " GENERIC" DATA SOURCES
- EREAKER DATA - (LER's, NPRDS,B&W RECORDS, OTHERS)
- RANDOM
- U.V. DEVICE & TRIP SHAFT (MECHANICAL AND HUMAN ADJUSTMENT)
- SHUNT TRIP
- INDETERMINATE ASSIGNED TO "OVERALL CATASTROPHIC"
- CMF
- MORE THAN ONE BREAKER AFFECTED REGARDLESS OF CAUSE OR FAILURE MODE
- SENSORS AND INSTRUMENT STRINGS
- NUREG/CR-3289 " COMMON CAUSE FAULT RATES FOR INSTRUMENT AND CONTROL ASSEMBLIES"
- LER SOURCE
- ALL FAILURE MODES LUMPED (REDUCED CAPABILITY AND INOPERABILITY)
- EVALUATION MODEL ACCOUNTED FOR NUREG DATA COMBINATIONS OF
" LETHAL SHOCK" (ALL CHANNELS), "NON-LETHAL" (MORE THAN ONE CHANNEL POTENTIALLY FAILED), AND MULTIPLE RANDOM FAILURES
- RELAYS (REACTOR TRIP MODULES, ELECTRONIC TRIP)
- CMF SEARCH (IE BULLETINS, NPRDS, ETC.)
- NO BASIS FOR CMF
- RANDOM - IEEE 500
- DATA
- CONSTANT FAILURE RATES - NO BASIS FOR A TIME DEPENDENT FAILURE RATE WAS FOUND
- FAILURE RATE PER HOUR VS. PER DEMAND
- UPPER BOUND - X2 (954 UPPER CONFIDENCE LIMIT) 15
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SUMMARY
RANDOM CMF BEST ESTIMATE BEST ESTIMATE REPAIR COMPONENT (PER HOUR)
(PER HOUR)
TIME U.V. DEVICE 1.13 x 10-5 (TWO) 6.2 x 10~7 TRIPPED (THREE) 6.88 x 10-6 TRIPPED SHUNT TRIP 9.91 x 10~7 TRIPPED (INCL. TRIP SHAFT AND.
HUMAN ADJ.
ERRORS)
ALL OTHER 1.55 x 10-6 TRIPPED BREARER COMPONENTS SHUNT TRIP 0.89 x 10-6 314 H POWER RELAYS
- 7. x 10-8 TRIPPED 1.NALOG 1.81 x 10-6 TO TO2.66x10~go-8 (TWO) 6.29 x (ONE) UNREPAIRED SENSORS 5.L x 10-6 UNTIL (THREE) 3.87 x 10~7 REFUELING TO 6.8 x 10~7 (TWO OR MORE)
SHUTDOWN DIGITAL 7.37 X 10-6 (TWO) 1.17 x 10~7 UNREPAIRED TO 1.69 x 10~g 10~7 SENSORS (THREE) 5.42 UNTIL REFUELING SENSOR 5.1 x 10-6 (TWO) 1.47 x 10~7 (ONE)
INSTRUMENT (THREE) 1.1 x 10-6 108H STRINGS (TWO OR MORE)
SHUTDOWN l
23
I 3.-
TESTING - ANALYTICAL BASIS EXISTING INTERVAL EXTENDED INTERVAL SENSORS 18 MONTH SAME WdEKLY COMPARISON OF ANALOG INDICATORS BYPASS NOT REQUIRED INSTRUMENT STRINGS MONTHLY STAGGERING ALL TESTING ASSUMED TO OCCUR IN THE LAST MONTH OF THE EXTENDED INTERVAL; ONE WEEK PER CHANNEL (BOUNDS CMF FOR EVEN STAGGERING)
ONE CHANNEL PER WEEK BYPASSED (UNTRIPPED)
BYPASSED (UNTRIPPED)
(BYPASS EFFECT -
2/4 - 2/3)
OUTAGE - 8 HOURS OUTAGE - 8 HOURS RPS TRIP MODULES & BREAKERS MONTHLY STAGGERING ONE CHANNEL PER WEEK CHANNEL IN TRIP (TRIP SAME EFFECT -
MODULES - 2/4 - 1/3 BREAKERS - 1/2 X 2 - 1/2 OUTAGE - 0 (IN TRIPPED CONDITION)
ELECTRONIC TRIP MONTHLY (CHANNELS C&D)
SAME SAME AS BREAKER TESTING 16
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MAINTENANCE - ANALYTICAL BASIS SENSQES
- SING 2 SENSOR DETECTED FAIIED-
- NO REPAIR UNTIL NEXT SCHEDULED SHUTDOWN-(REFUELING)
.'MORE THAN ONE SENSOR FOR THE SAME PARAMETER DETECTED FAILED-
- IMMEDIATE PIANT SHUTDOWN l
INSTRUMENT STRINGS l
- REPAIRED UPON DETECTION OF FAILUREF IN BYPASS MODE l
- MTTR.- 108 HOURS RPS TRIP MODULES AND BREAEERS i
- REPAIRED OR REPLACED UPON DETECTIONT IN TRIP MODE l
ELECTRONIC TRIP
- SAME AS TRIP MODULES / BREAKERS SHUNT TRIP PONER. SUPPLY l
- SELF ANNUNCIATED; REPAIRED ON DETECTION
- MTTR - 314 HOURS I
L l
u
n-WEAROUT EVALUATION
- SEARCH FOR TIME DEPENDENT FAILURE RATES FOCUSED ON WEAROUT
- WEAROUT FOUND NOT TO BE IMPORTANT COMPONENTS OF I MEREST COMPONENT WEAROUT FAILURE MODE FINDING
- TRIP SHAFT LUBRICANT AGING / DIRT
- SALEM FAILURES /OTHERS
& BEARINGS
- CHANGE TO MOBIL 28
- SHUM TRIP ADDITION
- BOUNDED (10 TO 100 YEAR) i U.V. COIL INSUIATION & CONNECTOR
- NO FAILURES IDE MIFIED DETERIORATION
- FAIL SAFE U.V. LINKAGE FATIGUE / LOSS OF TENSION
- NO FAILURES IDENTIFIED
& SPRING
- NOT FAIL SAFE
- DETECTABLE BY RESPONSE TIME TESTING (18 MO)
- SHUM TRIP-BACKUP SHUW TRIP INSUIATION & CONNECTOR
- ONE FAILURE IDE MIFIED COIL DETERIORATION (12 YEAR TIME PERIOD)
- NOT FAIL SAFE
- DETECTABLE ON LINE-
- U.V. DEVICE-BACKUP MAIN BREAKER PIVOT WEAROUT/ SPRING
- NO FAILURES /NOT SPRING FAILURE OR FATIGUE EXPECTED ASSEMBLY
- DESIGNED FOR 12,500 CYCLES (~ 100 YEARS)
BREAKER WELDING SHUT
- NO FAILURES /NOT CO WACTS EXPECTED
- LOW POWER COMPARED TO RATING RPS SENSORS, VARIOUS
- NO CLEAR EVIDENCE l
- STRINGS, AVAILABLE TO INDICATE BISTABLES, WEAROUT RELATED l
RELAYS PROBLEMS l
18
?
'e PRELIMINARY RESUL'2S EXTENSION OF SENSOR STRING TEST INTERVAL IS APPROPRIATE RTS RELIABILITY IS HIGH
- DIVERSITY OF TRIP MECHANISNS (BREAKERS, ELECTRONIC TRIP)
- BREAEER (SNUNT TRIP, LUBRICANT)
SENSITIVITY STUDIES INDICATE:
WEAROUT NOT IMPORTANT C
SENSOR STRING OUTAGE TIME NOT IMPORTANT SPURIOUS TRIP FREQUENCY IS SIGNIFICANTLY REDUCED BY EXTENSION OF THE TEST INTERVAL
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- DELTA CORE NELT FREQUENCY
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