ML20156A144
| ML20156A144 | |
| Person / Time | |
|---|---|
| Site: | Quad Cities  |
| Issue date: | 06/04/2020 |
| From: | Christopher Hunter NRC/RES/DRA/PRB |
| To: | |
| Littlejohn J (301) 415-0428 | |
| References | |
| LER 1984-014-00 | |
| Download: ML20156A144 (6) | |
Text
PRECURSOR DESCRIPTION SHEET LER No.:
Event
Description:
Date of Event:
Plant:
254/84-014 Two LPCI Injection Valves Fail to Open August 8, 1984 Quad-Cities 1 EVENT DESCRIPTION
.Sequence During the cycle 7 refueling outage at 1625 h, while the operator was in the process of starting the SDC mode of the RHR system, both LPCI injection valves would not open.
RHR could be accomplished using the RWCS and the RHR system with the LPCI "B" valve 25% open.
The cause of the failure was a personnel error in 1980 during modifications:
a wiring design error.
It went undetected.
Corrective Action The valve stems were removed and replaced.
The wiring correction was made, and the wiring diagram was corrected to reflect the change.,
Plant/Event Data Systems Involved:
LPCI Components and Failure Modes Involved:
LPCI valves -
failed to open on demand Component Unavailability Duration:
4 years (720 h assumed for analysis; assumed failed during last surveillance test Plant Operating Mode:
2 (0% power)
Discovery Method:
In operation Reactor Age:
12.9 years Plant.Type:
BWR Comments The valve in the "B" LPCI train was 25% open.
That percentage has been assumed to be insufficient to supply adequate flow for decay DHR.
Event Identifier:
254/84-014 D-40
MODELING CONSIDERATIONS AND DECISIONS Initiators Modeled and Initiator Nonrecovery Estimate Postulated tran-Base sient, LOOP, and small-break LOCA Branches Impacted and Branch Nonrecovery Estimate LPCI-1.0 No recovery assumed possible based on event description RHR (SDC) 1.0' No recovery assu med, possible based on event description RIIR SW
,Base case No recovery assumed possible based on event description Plant Models Utilized BWR plant Class C Event Identifier:
254/84-014 D-41I
CONDITIONAL CORE DAMAGE PROBABILITY CALCULATIONS Event Identifier: 254/84-014 Event
Description:
Two LPCI Injection Valves Fail to Open Event Date:
8/8/84 Plant:
Quad Cities 1 UNAVAILABILITY, DUIRATION-720 NON-RECOVERABLE INITIATING EVENT PROBABILITIES TRANS LOOP LOCA SEQUENCE CONDITIONAL PROBABILITY SUMS End State/Initiator CV 8.2E-01 3.2E-03 8.OE-04
,Probabil ity TRANS LOOP LOCA Total
.5.6E-I1I 2.0E-1 I*
- 6.
4E-04 2.1E-05 5.4E-06 6
.7E-04
- 0.
OE+00 0.OE+00 0.0t+00 0.OE+00 DOMIINANT SEQUENCES End State: CV Conditional Probability:
4.8E-09 Event Identifier: 254/84-014 D-4 2
135 TRANS SCRAM -SLC.OR.RODS PCS/TRANS -SRV.CLOSE FW/PCS.TRANS HPCI RCIC/TRANS.OR.LOO1P.-SRV.ADS
-COND/FW.PCS RHR(SDC) -RHR(SPCOOL) /-LPCI.RHR(SDC)
End State: CD Conditional Probability-5.7E-04 101 TRANS -SCRAM PCS/TRANS SRV.CHALL/TRANS.-SCRAM -SRV.CUJSE -FW/PCS.TRANS RHR(SDC)
RHR(SPCOOL) /
C.I.AND.V/RHR(SDC).RHR(SPCOOL)
SEQUENCE CONDITIONAL PROBABILITIES Sequence End State Prob N Rec**
101 TRANS -SCRAM PCS/TRANS SRV.CHALL/TRANS.-SCRAM -SRV.CLOSE -FW
C.I.AND.
VIRHR (SDC).RHR(SPCOOL) 102 TRANS -SCRAM PCS/TRANS SRV.CHAL/TRANS.-SCRAM -SRV.CLOSE FW
C.
I
.AND.V/RHR(SDC).RHR(SPCOOL) 135 TRANS SCRAM -SLC.OR.RODS PCS/TRANS -SRV.CLOSE FW/PCS.TRANS I4PCI RCIC/TRANS.OR.LOOP -SRV.ADS -COND/FW.PCS RHR(SDC)
RHR(SPCOOL)/-LPCI.RHR(SDC) 139 TRANS SCRAM -SLC.OR.RGDS PCS/TRANS -SRV.CLOSE FWIPCS.TRANS HPCI RCIC/TRANS.OR.LOOP -SRV.ADS COND/FW.PCS -LPCS RHR(
SDC) -RHR (SPCOOL-)/-LPCI.RHR(SDC) 156 TRANS SCRAM -SLC.OR.RODS PCS/TRANS SRV.CLOSE FW/PCS.LOCA HPCI RCIC/LOCA -SRV.ADS -COND/FW.PCS RH4R(SDC) -RHR(SPCOO L) /-LPCI.RHR(SDC) 160 TRANS SCRAM -SLC.OR.RI)DS PCS/TRANS SRV.CLOSE FW/PCS.LOCA HPCI RCIC/LOCA -SRV.ADS COND/FW.PCS -LPCS RHR(SDC) -RHR (SPCOOL) /-LPCI.RHR(SDC) 201 LOOP -EMER6.POWER -SCRAM 61W.CHALL/LOOP.-SCRAM -SRV.CLOSE -HP CI RHR(SDC)
C.I.AND.V/RHR(SD C)
.RHR(SPCOOL) 227 LOOP -EMERG.POWER SCRAM -SLC.OR.RODS HPCI RCIC/TRANS.OR.LOO P -SRV.ADS -LPCS RHR(SDC) -RHR(SPCOOL)/-LPCI.RHR(SDC) 315 LOCA SCRAM -SLC.OR.RODS PCS/LOCA FW/PCS.LOCA HPCI -SRV.ADS
-COND/FW.PCS RHR(SDC) -RHR(SPCOOL)/-LPCI.RHR(SDC)
CD CD CV CV Cv Cv CD CV Cv 5.7E-04
- 3.2E-01 5.9E-05 1.1E-01 4.8E-09
- 7.3E-02 2.5E-09 3.8E-02 2.9E-10 1.3E-01 1.5E-10 6.6E-02 2.OE-05 1.1E-01 2
.5E-09 1.5E-10 1.1E-01 4
.3E-02
- dominant sequence for end'state
- 1non-recovery credit for edited case Note: For unavailabilities, conditional probability values are differential values which reflect the 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
- \\bwrctree.cmp b:\\qcprob.cinp No Recovery Limit Event Identifier: 254/84-014 D)-4 3
BRANCH FREQUENCIES/PROBABILITIES Branch System TRANS LOOP LOCA SCRAM SLC.OR.RODS PCS/TRANS PCS/LOCA SRV.CHALL/TRANS.-SCRAM SRV.CHALL/TRANS.SCRAM SRV.CHALL/LOOP.-SCRAM SRY.CHALL/LOOP.SCRAM SRV.CLOSE EMERG.POWER FW/PCS.TRANS FW/PCS.LOCA HPCI RCIC/TRANS.OR.LOOP RCIC/LOCA CRD SRV.ADS COND/FW.PCS LPCS LPCI(RHR)/LPCS Branch Model:
1.OF.2 Train 1 Cond Prob:
Train 2 Cond Prob:
RHRSW/LPCS.LPCI.TRANS Branch Model: '
.OF.1+opr Train 1 Cond Prob:
RHRSW/LPCS.LPCI.LOOP Branch Model: 1.OF.1+opr Train 1 Cond Prob:
RHRSbJ/LPCS.LPCI SLOCA Branch Model: 1.OF.I~opr Train 1 Cond Prob:
Branch Model: 1
.OF.2+ser Train 1 Cond Prob:
Train 2 Cond Prab:
Serial Component Prob:
RHR(SDC)/-LPCI RHR(SDC) /LPCI RHR(SPCOOL)/-LPCI.RHR(SDC)
Event Identifier: 254/84-014 1
.1E-03 1.3E-05 3.3E-06
- 4.
1E-04 1.OE-02 1.7E-01 I.OE+00
- 1. OE+00 1.0E+00 1.0E+00 1.OE+00 1.6E-02 2.9E-03 2.9E-01 4.OE-02 I.OE-01 6
.7E-02 1.0E+00 1.~0E-02 6.7E-03 1.0E+00 3.OE-03 4.OE-04 > 1.0E+00 Non-Recov 1.OE+00 3.4E-01 3.4E-01 1.OE+00 1
.0E+00 1.0E+00 1.0E+00 1.0E+00 1.0E+00 1.0E+00 1.0EO00 1.0E+00 5.1E-01 3.4E-01 3.4E-01 5.7E-01 5.7E-01 1.0E+00 1.0E+00 1.0E+00 3.4E-01 3.4E-01 3.4E-01 > 1.OE+00 1.0E+00 1.0E+00 I.OE+00 3.4E-01 > 1.DE+00 3.4E-01 1.0E+00 1
.0E+00
- 1.
OE+00 Opr Fail 4.OE-02 4.OE-02 4.OE-02 4.OE-03 1.OE-01 5
.OE-01
> Failed
> Failed
> 1.0E+00 5.OE-01 > Failed 5.OE-01 > 1.0E+00 5.OE-01 > Failed 5.OE-01 > 1.0E+00 5.OE-01 > Failed 2.OE-02 > 1.OE+00 4.OE-03 > Failed 1.GE-01 > Failed 2.OE-02 2.OE-02 1.0E+00 2
.OE-02 5.2E-01 4.OE-02 4.OE-02 4.OE-02 i>-44
C.I.AND.V/RHR(SDC).RHR(SPCOOL) forced Minarick 04-11-1 987 13.-47:04 Event Identifier: 254/84-014 1
.OE.00 3.E-01 D-4 5