ML20156A209
| ML20156A209 | |
| Person / Time | |
|---|---|
| Site: | Salem  |
| Issue date: | 06/04/2020 |
| From: | Christopher Hunter NRC/RES/DRA/PRB |
| To: | |
| Littlejohn J (301) 415-0428 | |
| References | |
| LER 1984-017-00 | |
| Download: ML20156A209 (5) | |
Text
PRECURSOR DESCRIPTION SHEET LER No.:
272/84-017 Event
Description:
Unavailability of High-Head Charging Pumps Date of Event:
July 16, 1984 Plant:
Salem 1 EVENT DESCRIPTION Sequence While performing surveillance testing of charging pump 12, the pump-seized after running for -.30 s.
Charging pump 12 was declared inoper-able; the redundant charging pumps remained operable.
Upon disassembly' of the pump, a small amount of resin particles and metal filings were discovered in the pump casing.
As a result of these findings, an in-vestigation ensued to determine the source and extent of the problem.
Similar material was found in the common suction line of all charging pumps.
It has been assumed (because of the extremely close internal tolerances in the centrifugal charging pumps) that the other charging pumps would also have failed as a result of the metal filings.
Corrective Action Replaced rotating element in the charging pump.
Suction lines were cleaned and temporary strainers installed.
Plant/Event Data Systems Involved:
RHI S Components and Failure Modes Involved:
Charging pump 12 -
failed on demand Remaining charging pumps -
potentially failed on demand Component Unavailability Duration:
360 h (postulated)
Plant Operating Mode:
6 (0% power)
Discovery Method:
During testing Reactor Age:
3.9 years Plant Type:
PWR Comments This unavailability possibly could have been discovered during startup checks; however, it is being conservatively modeled as if it could have rendered HPI unavailable at power.
Event Identifier:
272/84-017 D-7 3
MODELING CONSIDERATIONS AND DECISIONS Initiators Modeled and Initiator Nonrecovery Estimate Postulated tran-Base case sient, LOOP, and LOCA Branches Impacted and Branch Nonrecovery Estimate HPI 1.0 No recovery is assumed possible Bleed and feed 1.0 No recovery is assumed possible Plant Models Utilized PWR plant Class B Event Identifier:
272/84-017 D-74
CONDITIONAL CORE DAMAGE PROBABILITY CALCULATIONS Event Identifier: 272/84-017 Event
Description:
Unavailability of High-Head Charging Pumps Event Date:
7/16/84 Plant:
Salem 1 UNAVAILABILITY, DURATION= 360 NON-RECOVERABLE INITIATING EVENT PROBABILITIES TRANS LOOP LOCA SEQUENCE CONDITIONAL PROBABILITY SLIMS End State/Initiator CV 3.E-01 2.8E-03
- 5.
IE-04 Probability TRANS LOOP LOCA Total 1.6E-03 6.2E-07 4
.BE-04
- 2.
1E-03 CD TRANS LOOP LOCA Total ATWS TRANS LOOP LOCA Total 2.OE-06 7.OE-07 4
.5E-06 7.3E-06 0.OE+O0 0.OE+00 0.OE+00 0.OE+00 DOMINANT SEQUENCES End State: CV Event Identifier: 272/84-017 Conditional Probability:
1.5E-03 Dý-75
109 TRANS -RT -AFW -PORV.JR.SRV.CHALL SS.RELEAS.TERM HPI End State: CD Conditional Probability:--
1.8E-05 307 LOCA -RT -AFW HPI SS.DEPRESS SEQUENCE CONDITIONAL PROBABILITIES Sequence End State
- Prob, N
-Rec*f 101 TRANS -RT -AFW PORV.OR.SRV.CHALL -PORV.OR.SRV.RESEAT SS.RELE AS.TERM HPI 109 TRANS -RT -AFW -PORV.OR.SRV.CHALL SS.RELEAS.TERM Ff1 126 TRANS -RT AFW OFW HPI (F/B) -56.DEPRESS COND/MFW 214 LOOP -RT/LOOP -EMERG.POW'ER AFW HPI(F/B) 304 LOCA -RT -AFW HP! -SS.DEPRESS -LPI/HPI -LPR/HPI 307 LOCA -RT -AFW HPI 95.DEPRESS CV CV CD CD CV CD 6.3E-05 3.4E-01 1.5E-03 *~3.4E-01 1.9E-06 3.1E-02 7.3E-07 9.2E-02 4.9E-04 3.4E-01 1.BE-05
-3.4E-01
- dominant sequence for end state
- non-recovery credit for edited case Note: For unavailabilities, conditional probability values are differential values which refflectthe added risk due to failures associated with an event. Parenthetical values indicate a reduction in risk compared to a similar period without the existing failures.
MODEL:
DATA:
b
- \\pwrbtree.cmp b:\\salempro.cmp No Recovery Limit BRANCH FREQUJENCIES/PROBABILITIES Branch System Non-Recov Opr Fail TRANS LOOP LOCA RT RT/LOOP EMERS.POWER AFW AFW/EMERS.POWER MFW PORV.OR.SRV.CHALL PORV.OR.SRV.RESEAT PORV.OR.61W.RESEAT/EMERS.POWER 66.RELEAS.TERM SB.RELEAS.TERM/-MFW HP!
Event Identifier: 272/84-017
- 1.
OE-03 2.3E-05 4
.E-06 2
.5E-04 0.OE+00 5
.4E-04 1.OE-03 5
.OE-02 2.OE-01 4.E-02 2.OE-02 2
.OE-02 1
.5E-02 1.5E-02 1.0E-03 > 1.OE+00 1.0E+00 3.4E-01 3
.4E-01 1.2E-01 1.0E+00 5.1E-01 2.7E-01 3.4E-01 3.4E-01 1
.OE+00 5
.OE-02 5
.OE-02 3.4E-01 3
.4E-01 5.2E-01 > 1.0E+00 1)-76
Branch Model : 1.OF.2 Train 1 Cond Prob:
Train 2 Corid Prob:
WPI (F/B)
Branch Model:
l.OF.2+opr Train 1 Cond Prob:
Train 2 Cond Prob:
PORV.WE SS.DEPRESS COND/MFW LPI/WIf LPR/-WIHPI~R LPR/HPI
- forced Minarick 04-11:-1987 14:26:35 1.0E-02 > Failed 1.OE-01 > Failed 1.OE-03 ) 1.0E+00 1.OE-02 > Failed 1.OE-01 > Failed 3.OE-03 1.0E-02 3.6E-02 1.OE+00 1 OE-03 6.7E-01 1.OE-03 5.2E-01 > 1.OE+O0 5.6E-01 1.OE+00 1.OE+00 3.4E-01 3A.E-01 1
.OE+00 1.OE+00 4
.OE-02 4 OE-02 Event Identifier: 272/84-017 D-77