ML20156A137

Final ASP Analysis - Pilgrim (LER 293-85-027)

ML20156A137
Person / Time
Site:	Pilgrim
Issue date:	06/04/2020
From:	Christopher Hunter NRC/RES/DRA/PRB
To:
Littlejohn J (301) 415-0428
References
LER 1985-027-00
Download: ML20156A137 (5)

Text

PRECURSOR DESCRIPTION SHEET LER No.:

Event

Description:

Date of Event:

Plant:

293/85-027 LPCI Made Inoperable for Modifications September 19, 1985 Pilgrim 1 EVENT DESCRIPTION Sequence The LPCI was out of service for equipment qualification work when the loop "B" injection valve failed to open in a test because of a failed motor.

The motor failed from aging and wear.

Corrective Action The valve was repaired.

Plant/Event Data Systems Involved:

LPCI Components and Failure Modes Involved:

Injection valve -

failed in test Component Unavailability Duration:

32.5 h Plant Operating Mode:

1 (100% power)

Discovery Method:

Testing Reactor Age:

13.3 years Plant Type:

BWR Comments The LER indicates the "LPCI system" was inoperable and that only RHR train A and LPCS were available, which implies RHR B train B was inoperable.

Therefore, LPCI injection capability and RHR train B were assumed unavailable.

Event Identifier:

293/85-027 E-130

MODELING CONSIDERATIONS AND DECISIONS Initiators Modeled and Initiator Nonrecovery Estimate Transient, LOOP, Base case small LOCA (postulated event)

Branches Impacted and Branch Nonrecovery Estimate LPCI 1.0 Not recoverable iq (as sumed)

RHR Base case One train unavailable Plant Models Utilized BWR plant Class C ithin

--30 min Event Identifier:

293/85-027 E-131

CONDITIONAL CORE DAMAGE CALCULATIONS LER Number:

Event

Description:

Event Date:

Plant.

293/85-027 LPCI Made Inoperable for Modifications 9/19/85 Pilgrim UNAVAILABILITY, DURATION= 32.5 NON-RECOVERABLE INITIATING EVENT PROBABILITIES TRANS LOOP LOCA SEQUENCE CONDITIONAL PROBABILITY SUMS End State/Initiator

3.

712E-02

1. 442E-04

3.

591E-05 Probability CV TRANS LOOP LOCA Total

2.

225E-13, 9.005E-14 4.503E-15

3.

250E-13 CD TRANS LOOP LOCA Total

1.

39BE-06

3.

260E-08 B.

109E-09

1.

439E-06 ATWS TRANS LOOP LOCA Total

0.

OOOE+00

0.

OO0E+00

0.

OOOE+0O

0.

OOOE+00 DOMINANT SEQUENCES End State:

CV Conditional Probability:

1.046E-11 135 TRANS SCRAM -SLC.OR.RODS PCS/TRANS -SRV.CLOSE FWIPCS.TRANS HPCI RCIC/TRANS.OR.LOOP -SRV.ADS -COND/F Event Identifier: 293/85-027 E-1 32

W.PCS RHR(SDC) -RHR(SPCOOL)I-LPCI.RHR(SDC)

End State: CD Conditional Probability:

l.243E-06 101 TRANS -SCRAM PCS/TRANS SRV.CHALL/TRANS.-SCRAM -SRV.CLOSE -FW/PCS.TRANS RHR(SDC) RHR(SPCOOL)/-LPCI.RH R(SDC)

C.I.AND.V/RHR(SDC).RHR(SPCaOL)

SEQUENCE CONDITIONAL PROBABILITIES Sequence End State Seq. Prob Non-Recov*f 101 TRANS -SCRAM PCS/TRANS SRV.CHALL/TRANS.-SCRAN -SRV.CLOSE -FW

/PCS.TRANS RHR(SDC) RHR(SPCOOL)I-LPCI.RHR(SDC) C.I.AND.

V/RHR(SDCI.RHR(SPCOOL) 102 TRANS -SCRAM PCS/TRANS SRV.CHALL/TRANS. -SCRAM -SRV.CLOSE FW

/PCS.TRANS -HPCI RHR(SDC) RHR(SPCOOL)/-LPCI.RHR(SDC) C.

I.AND.V/RHR(SDC).RHR(SPCOOL) 135J TRANS SCRAM -SLC.OR.RODS PCSITRANS -SRV.CLOSE FWIPCS.TRANS HPCI RCIC/TRANS.OR.LOOP -SRV.ADS -COND/FW.PCS RHR(SDC) -

RHR(SPCOOL) /-LPCI.RHR(SDC) 139 TRANS SCRAM -SLC.OR.RODS PCS/TRANS -SRV.CLOSE FW/PCS.TRANS HPCI RCIC/TRANS.OR.LOOP -SRV.ADS COND/FW.PCS -LPCS RHR(

SOC) -RHR(SPCOOL) /-LPCI.RHR(SDC) 156 TRANS SCRAM -SLC.OR.RODS PCS/TRANS SRV.CLO SE FW/PCS.LOCA HPCI RCIC/LOCA -SRV.ADS -COND/FW.PCS RHR(SDC) -RHR(SPCOO L)/-LPCI.RHR(SDC) 227 LOOP -EMERG.POWER SCRAM -SLC.OR.RODS HPCI RCIC/TRANS.OR.LOO P -SRV.ADS -LPCS RHR(SDC) -RHR(SPCOULI /-LPCI.RHR(SDC)

CD CD CV 1.243E-06

• 1.073E-01

1.

282E-07

3.

82BE-02 1.046E-11 *2.2W5-02 5.385E-*12 1.177E-02 5.055E-13 4.OOBE-02 3.782E-12 3.461E-02 CV CV

• dominant sequence for end state 1*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-DATA-b:bwrctree.cmp b:pilgprob.cep No Recovery Limit BRANCH FREQUENCIES/PROBABILITIES Branch TRANS LOOP LOCA SCRAM Event Identifier: 293/85-027 System

1.

142E-03

1.

305E-05

3.

250E-06

4.

IOOE-04 Non-Recov 1.000E+00

3.

400E-01

3.

400E-01

1.

OOOE+00 Opr Fail E-1 33

SLC.OR. RODS PCS/TRANS PCS/LOCA SRV. CHALL/TRANS. -SCRAM SRV. CHALL/TRANS. SCRAM SRV. CHALL/LGOP. -SCRAM SRV.CHALL/LOOP. SCRAM SRV. CLOSE EMERG. POWER FW/PCS. TRANS FW/PCS. LOCA HPC I RCIC/TRANS. OR. LOOP RCIC/LOCA CR0 SRV. ADS COND/FW. PCS LPCS LPCI (RHR) /LPCS Branch Model:

1.OF.2 Train 1 Cond Prob:

Train 2 Cond Prob:

RHRSI4/LPCS. LPCI. TRANS RHRSW/LPCS. LPCI.LOOP RHRSW/LPCS. LPCI.LOCA RHR (SDC)

Branch Model:

1.OF.2+5er Train 1 Cond Prob:

Train 2 Cond Prob:

Serial Component Probability:

RHR(SDC) /-LPCI RHR(SDC)/LPCI RHR(SPCOOL) /-LPCI.RHR (SDC)

RHR (SPCOOL) /LPCI.RHR (SDC)

C.

I.AND.Y/RHR(SDC).RHR(SPCOOL) f** forced Austin 08-14-1986 13: 28:41 Event Identifier:

293/85-027

1.

OOOE-02

1.

700E-01I

1.

OOOE+00

1.

OO0E+00

1.

OOOE+O0

1. OOOE+00 1.000E+00

1.

320E-02

2. 850E-03

2. 900E-01

4. OOOE-02

1. OOOE-01 6.7100E -02

1. OOOE+00

1.

OOOE-02

6.

700E-03

1.

000E+00

3. OOOE-03 4.OOOE-04 >1.0OOE+00 4.O00E-03 > Unavailable 1.000E-01 ) Unavailable

5.

OOOE-01

5.

000E-01

5. OOOE-01 2.039E-02 > 1.180E-01 4.OOOE-03) ) Failed

1. 000E-01

2. 000E-02

2. 000E-02

1.

000E+00 2.000OE-02

5. 200E-01 1.0O0E+00

1.

OOOE+00

1.

O0OE+00

1.

O00E+00

1.

OOOE+00

1.

OOOE+00

1.

OOOE+00

1.

OOOE+00

1.

OOOE+00

5.

IOOE-01

3.

400E-01

3.

400E-01

5.

700E-01

5.

7O0E-01

1. OOOE+00

1.

OOOE+00

1.

000E+00

3.

400E-01

31.

400E-01I 3.400E-01 > 1.000E+00

1.

000E 400

1. OO0E+00

1. OOOE+00 3.400E-01 4.O0OE-02

4.

OOOE-02

4. OOOE-02

4. OOOE-02

4.

OOOE-02

4.

OOOE-02

3.

400E-01

1.

OOOE+00

1.

OOOE+0O

1.

OOOE+00

3.

400E-01 E-134