ML20149K335
| ML20149K335 | |
| Person / Time | |
|---|---|
| Site: | FitzPatrick  |
| Issue date: | 05/28/2020 |
| From: | Christopher Hunter NRC/RES/DRA/PRB |
| To: | |
| Littlejohn J (301) 415-0428 | |
| References | |
| LER 1985-025-00 | |
| Download: ML20149K335 (5) | |
Text
LER No. :
Event
Description:
Date of Event:
Plant:
PRECURSOR DESCRIPTION SHEET 333/85 -025 HPCI and RCIC Unavailable June 29, 1985 Fitzpatrick EVENT DESCRIPTION Sequence A motor operator failed on the HPCI[
steam supply, isolation valve, rendering HPCI unavailable.
The motor operator failure was caused by an improper torque switch setting (caused by a loosened locking screw).
The torque setting allowed the valve operator to exceed its maximum allowable torque.
The valve had been potentially inoperable for six weeks. 'RCIC was already unavailable because of preventive maintenance activities.
The H-PCI motor operator was repaired before RCIC could be made available.
Corrective Action HPCI steam isolation valve operator was replaced.
Plant/Event Data Systems Involved:
HPCI and RCIC Components and Failure Modes Involved:
Valve operator motor -
failure on demand Component Unavailability Duration:
19 h for RCIC, 6 weeks f or HPCI, 19 h combined HPCI/RCIC unavailability Plant Operating Mode:
1 (100% power)
Discovery Method:
Testing Reactor Age:
10.2 years Plant Type:
BWR Comments None Event Identifier:
333/85-025 E-191
MODELING CONSIDERATIONS AND DECISIONS Initiators Modeled and Initiator Nonrecovery Estimate Transient, LOOP, Base case small tOGA (postulated event)
Branches Impacted and Branch Nonrecovery Estimate RCIC 1.0 Not restorable from maintenance status in a reasonable time HPCI 0.34 Valve could be manually controlled locally; valve operator was removed for repairs, making system unavailable Plant Models Utilized BWR plant Class C Event Identifier:
333/85-025 E-192
CONDITIONAL CORE DAMAGE CALCULATIONS LER Number:
Event
Description:
Event Date:
Plant:
333/85-025 HPCI and RCIC Unavailable 6/29/85 Fitzpatrick UNAVAILABILITY, DURATION= 19 NON-RECOVERABLE INITIATING EVENT PROBABILITIES TRANS LOOP LOCA SEQUENCE CONDITIONAL PROBABILITY SUMS End State/Initiator
- 2.
- 8.
- 2.
100OE-05 Probability CV TRANS LOOP LOCA Total
- 7. 322E-08
- 1.
- 7. 506E-10
- 8.
453E-08 CD TRANS LOOP LOCA Total B.
- 1.
- 9.
- 1.
104E-06 ATWS TRANS LOOP LOCA Tatal
- 0.
OOOE+00
- 0.
OOOE+00
- 0.
OOOE+00
- 0.
OOOE+00 DOMINANT SEQUENCES End State:
CV Conditional Probability.
4.568E-00 134 TRANS SCRAM -SLC.GR.RODS PCS/TRANS -SRV.CLOSE FW/PCS.TRANS HPCI RCIC/TRANS.OR.LOOP -SRV.ADS -COND/F Event Identifier: 333/85-025 E-193
End State:
CD Conditional Probability:
4.400E-07 119 TRANS -SCRAM PCS/TRANS SRV.CHALL/TRANS.-SCRAM SRV.CLOSE FW/PCS.LGCA HPCI RCIC/LOCA SRV.ADS SEQUENCE CONDITIONAL PROBABILITIES Sequence End State Seq. Prob Non-Recovl*
110 TRANS -SCRAM PCS/TRANS SRV.CHALL/TRANS.-SCRAM -SRV.CLOSE FM CD 4.31BE-07 4.221E-03
/PCS.TRANS HPCI RCIC/TRANS.OR.LOOP CR0 SRV.ADS 119 TRANS -SCRAM PCS/TRANS SRV.CHALL/TRANS.-SCRAM SRY.CLOSE FM CD 4.400E-07
- 1.936E-02
/PCS.LOCA HPCI RCIC/LOCA SRV.ADS 134 TRANS SCRAM -SLC.OR.RODS PCS/TRANS -SRV.CLOSE FW/PCS.TRANS CV 4.568E-08
- 6.999E-02 HPCI RCIC/TRANS.OR.LOOP -SRV.ADS -COND/FW.PCS -RHR(SDC) 138 TRANS SCRAM -SLC.OR.RODS PCS/TRANS -SRV.CLOSE FM/PCS.TRANS CV 1".351E-08 3.606E-02 HPCI RCIC/TRANS.OR.LOOP -SRV.ADS COND/FW.PCS -LPCS -RHR(
SDC) 155 TRANS SCRAM -SLC.OR.RODS PCSITRANS SRV.CLOSE FW/PCS.LOCA CV
- 2.
- 6.
999E-02 HPCI RCIC/LOCA -SRY.ADS -COND/FM.PCS -RHR(SDC) 208 LOOP -EMERG.POMER -SCRAM SRY.CHALL/LOOP.-SCRAM -SRV.CLOSE HP CD 6.'367E-OB 4.221E-03 CI RCIC/TRANS.QR.LOOP CRD SRY.ADS 215 LOOP -EMERG.POWER -SCRAM SRV.CHALL/LOOP.-SCRAM SRV.CLOSE HP Co 2.984E-08 1.936E-02 CI RCIC/LOCA SRV.ADS 226 LOOP -EMERG.POWER SCRAM -SLC.OR.RODS HPCI RCIC/TRANS.OR.LOO CV l.048E-08 1.060E-01 P -SRV.ADS -LPCS -RHR(SDC) 243 LOOP EMERG.POWER -SCRAM SRV.CHALL/LOOP. -SCRAM -SRV.CLOSE HP CO 4.024E-08 5.B96E-02 CI RCIC/TRANS.GR.LOOP 30 LOCA -SCRAM PCS/LOCA FM/PCS.LOCA HPCI RCIC/LOCA SRV.ADS C
.7E0
.8E0 Idominant sequence for end state "non-recovery credit for edited case Note:
Conditional probability values are differential values which reflect the added risk due to observed failures.
Parenthetical values indicate a reduction in risk compared to a similar period without the existing failures.
MODEL:
b:borctree.cmp DATA:
b:fitzprob.cmp No Recovery Limit BRANCH FREQUENCIES/PROBABILITIES Branch System Non-Recov Opr Fail TRANS 1.142E-03 1.000E+00 LOOP 1.305E-05 3.400E-01 Event Identifier: 333/85-025 E-194
LOCA SCRAM SLC. OR. RODS PCS/TRANS PCS/LOCA SRV. CHALL/TRANS. -SCRAM SRV.CHALL/TRANS. SCRAM SRV.CHALL/LOGP.-SCRAM SRV.CHALL/LOOP. SCRAM SRV. CLOSE EMERG. POWER FWIPCS. TRANS FW/PCS. LOCA HPCI Branch Model:
1.OF.1 Train I Cond Prob:
RCIC/TRANS. OR. LOOP Branch Model:
1.0F.1 Train 1 Cond Prob:
RCIC/LOCA Branch Model:
1.OF.1 Train I Cond Prob:
CRD SRV. ADS COND/FW. PCS LPCS LPCI (RHR) /LPCS RHRSW/LPCS. LPCI. TRANS RHRSW/LPCS.LPCI.LOOP RHRSW/LPCS. LPCI.LOCA RHR(SDC)
RHR (SDC) I-LPCI RHR(SOC) /LPCI RHR(SPCOOL) I-LPCI.RHR(SDC)
C.
- 3. 250E-06
- 4. IOOE-04
- 1.
OOOE-02
- 1.
700E-0 I
- 1. OOOE400
- 1.
O0OE+00
- 1.
OOOE+00
- 1.
OOOE+00
- 1.
OOOE+00
- 2.
700E-02 2.850E-03
- 4. 600E-01
- 1.
OOOE.00 I.000E-01 > 1.00OE+00 1.OOOE-01 '/
Failed 6.700E-02 > 1.000E+00 6.700E-02 > Unavailable 1.00OE+00 > l.OOOE+O0 l.OOOE+00 > Unavailable
- 1.
OOOE-02
- 6.
700E-03 1.OOOE+O0
- 3. OOOE-03
- 4.
OOOE-04
- 5. OOOE-01
- 5. OOOE-01 5.OOOE-01
- 2.
039E-02 2..OOOE-02 1.OOOE+O0 2.000OE-074
- 5. 200E-01
- 1.
OO0E+00 3). 400E-01I
- 1. OOOE+00
- 1.
OOOE+00
- 1.
OOOE+00
- 1.
OOOE+00
- 1.
OOOE+00
- 1.
OOOE+00
- 1.
OOOE+00
- 1. OOOE+00
- 1. OOOE+00
- 5.
1 O0E-0lI
- 3.
- 3.
400E-01 5.700E-01 > 3.400E-01 5.700E-01 > 1.000E+00
- 1. OOOE+00 1.000OE+00 1.000E+00 3).400E-01
- 3.
- 3.
400E-01 1.000OE+00
- 1. OOOE+00 1.OOOE+00
- 3.
- 3.
- 1. OOOE+00 1.OOOE+00
- 1. OOOE+00
- 3.
- 4. OOOE-02 4.OOOE-02
- 4. OOOE-02
- 4. OOOE-02
- 4. OOOE-02
- 4. OOOE-02 1**
forced Minarick 08-13-1986 05:01:37 Event Identifier: 333/85-025 E-195