ML20147A474

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Final ASP Analysis - Brunswick 2 (LER 324-84-014)
ML20147A474
Person / Time
Site: Brunswick 
Issue date: 05/26/2020
From: Christopher Hunter
Office of Nuclear Regulatory Research
To:
Littlejohn J (301) 415-0428
References
LER 1984-014-00, LER 1984-018-00
Download: ML20147A474 (5)
v • d • e


Text

PRECURSOR DESCRIPTION SHEET LER No.:

324/84-014, -018 Event

Description:

RCIC and Train "B" LPCI/RHR Unavailable Date of Event:

November 27, 1984 Plant:

Brunswick 2 EVENT DESCRIPTION Sequence At 1023 h on November 27, 1984, a main turbine trip and stop valve closure caused a main turbine moisture s eparat or -reheat er (MSR) high-level trip signal.

An automatic reactor scram of Unit 2 resulted.

The LPCI train B was inoperable due to excessive seat leakage past the inboard primary containment IV, 2-E11-FO15B.

This leakage also rendered RHR train B inoperable.

In addition, the RCIC system was inoperable due to failure to meet the in-service test requirement for pump-developed pressure as a function of pump flow criteria.

Later, while the unit was being placed in shutdown cooling mode, RHR loop A experienced a water hammer in the steam condensing piping, which rendered the loop inoper-able.

The main condenser was then utilized for shutdown cooling.

After supports and snubbers were repaired, RHR was restored to service.

Corrective Action The MSR high-level actuation switch, 2-MD-LSH-MS-2, was cleaned and tested for proper operation.

An inspection revealed that the instrument float plunger was loose.

The float plunger was tightened, and the in-strument was returned to service.

Plant/Event Data Systems Involved:

LPCI, RCIC, and secondary-side instrumentation.

Components and Failure Modes Involved:

MSR high-level actuation switch -

failed high LPCI train B -

unavailable RCIC -

unavailable Component Unavailability Duration:

NA Plant Operating Mode:

1 (98% power)

Discovery Method:

Operational event Reactor Age:

9.7 years Plant Type:

BWR Event Identifier: 324/84-014, -018 D-115

MODELING CONSIDERATIONS AND DECISIONS Comments Due to lack of information, RCIC unavailability is assumed.

Initiators Modeled and Initiator Nonrecovery Estimate Transient 1.0 Nonrecoverable Branches Impacted and Branch Non-Recovery Estimate LPCI Base case Degraded (train 2 unavailable)

RCIC 1.0 Failed, not recoverable to full operability in required time frame RHR (SDC) 0.12 Failed (but operator could open the containment isolation valves from the control room)

Plant Models Utilized BWR plant Class C Event Identifier: 324/84-014, -018 D-116

CONDITIONAL CORE DAMAGE PROBABILITY CALCULATIONS Event Identifier: 324/84-014 Event

Description:

RCIC and Train "JB" LPCI/RHR Unavailable Event Date:

11/27.184 Plant:

Brunswick 2 INITIATING EVENT NON-RECOVERABLE INITIATING EVENT PROBABILITIES TRANS SEQUENCE CONDITIONAL PROBABILITY SUMS End State/Initiator 1

.0E+00 Probability CV TRANS Total 5.8E-07 5.8E-07 CD TRANS Total 1

.4E-04 1

.4E-04 ATWS TRANS Total 2.OE-05 2.OE-05 DOMINANT SEQUENCES End State: CV Conditional Probability*.

3.2E-07 134 TRANS SCRAM -SLC.OR.RODS PCS/TRANS -SRV.CLOSE FW/PCS.TRANS HPCI RCIC/TRANS.OR.LOOP -SRV.ADS

-COND/FW.PCS -RHR(SDC)

End State: CD Conditional Probability:

8.2E-05 120 TRANS -SCRAM PCS/TRANS -SRV.CHALL/TRANS.-SCRAM

-FW/PCS.TRANS RHR(SDC)

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

C.I.ANO.V/RHR(SDC).RHR(SPCOOL)

Event Identifier: 324/84-014 ID-117

End State: ATWS EndStae: TWSConditional Probability:

2.OE-05 173 TRANS SCRAM SLC.OR.RODS SEQUENCE CONDITIONAL PROBABILITIES Sequence End State Prob N Rec**

101 TRANS -SCRAM PCS/TRANS SRV.CHALL/TRANS.-SCRAM -SRV.CLOSE -FW IPCS.TRANS RHR(SDC)

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

C.I.AND.

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

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

I

.AND.V/RHR(SDC).RHR(SPCOOL) 120 TRANS -SCRAM PCS/TRANS -SRV.CHALL/TRANS.-SCRAM -FW/PCS.TRANS RHR(SDC) RHR(SPCOOIJ/-LPCI.RHR(SBC) C.I.AND.V/RHR(SBC)..R HR (SPCOOL) 121 TRANS -SCRAM PCS/TRANS -SRV.CHALL/TRANS.-SCRAM FW/PCS.TRANS

-HPCI RHR(SDC) RHR(SPCODL)f-LPCI.RHR(SDC) C.I.AND.V/RHR (SOC).RHR(SPCOOL) 134 TRANS SCRAM -SLC.OR.RODS PCS/TRANS -SRV.CLOSE FW/PCS.TRANS HPCI RCIC/TRANS.OR.LOOP -SRV.ADS -COND/FW.PCS -RHR(SDC) 135 TRANS SCRAM -SLC.OR.RODS PCS/TRANS -SRV.CLOSE FW/PCS.TRANS HPCI RCIC/TRANS.OR.LOOP -SRV.ADS -COND/FW.PCS RHR(SDC) -

RHR(SPCOOL) f-LPCI.RHR(SDC) 138 TRANS SCRAM -SLC.OR.RODS PCS/TRANS -SRV.CLOSE FW/PCS.TRANS HPCI RCIC/TRANS.OR.LOOP -SRV.ADS COND/FW.PCS -LPCS -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.R1(R(SDC) 155 TRANS SCRAM -SLC.OR.RODS FCS/TRANS SRV.CLOSE FW/PCS.LOCA HPCI RCIC/LOCA -SRV.ADS -COND/FW.PCS -RHR(SDC) 159 TRANS SCRAM -SLC.OR.RODS PCS/TRANS SRV.CLOSE FW/PCS.LOCA HPCI RCIC/LOCA -SRV.ADS COND/FW.PCS -LPCS -RHR(SDC) 173 TRANS SCRAM SLC.OR.RODS CD CD CD CD CV CV Cv CV CV Cv 3.4E-05 3.6E-021 6.OE-06 1

.4E-02 8.21-05

  • 3.6E-02 1.4E-05 1.4E-02 3.2E-07
  • 1.1E-01 4.3E-08 1.5E-02 1.6E-07 5.8E-02 M.E-0 7.9E-03 1.9E-08 1.1E-01 9.9E-09 5.8E-02?

2.OE-05

  • dominant sequence for' end state
    • non-recovery credit for edited case MODEL:

DATA:

b :\\bwrctree.cmp b :\\brunprob.cmp No Recovery Limit BRANCH FREQUENCIES/PROBABILITIES Branch System Non-Recov Opr Fail Event Identifier: 324/84-014 D-118

TRANS LOOP LOCA SCRAM SLC.OR.RODS PCS/TRANS PCS/LOCA SRV.CHALL/TRANS.-SCRAM SRV.CHALL/TRANS.SCRAM SRY.CHALL/LOOP.-SCRAM SRV.CHALL/LOOP.SCRAM SRV).CLOSE EMERG.POWER FW/PCS.TRANS FW/PCS.LOCA HPCI RCIC/TRANS.OR.LOOP Branch Model:

1.OF.1 Train I Cond Prob:

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

Branch Model:

1.OF.2+ser Train 1 Cond Prob:

Train 2 Cond Prob:

Serial Component Prob:

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

RHR(SPCQOL) /LPCI.RHR(SDC)

C.I.AND.V/RHR(SDC).RHR(SPCOOJL) 1.1E-03 1.3E-05 3.3E-06

4. 1 E-04 1.OE-02 1.7E-01 I.OE+00 3.OE-01 1.0E+00 3.OE-01
1. 0E+00 2.7E-02 2.9E-03 4.6E-01 I.OE+00 1.OE-01 6.7E-02 > 1.0E+00 6.7E-02 > Failed 1.OE+60 1.OE-02 6.7E-03 1.0E+00 3.OE-03 4.OE-04 > 4.OE-03 4.OE-03 1.OE-01 > Unavailable 5.OE-01 5.OE-01 5.OE-01 2.OE-02 > 1.0E+00 4.OE-03 ) Failed 1.OE-01 > Failed 2.OE-02 2.OE-02 1.OE+00 2.OE-02 5.2E-01 1.0E+00 1.0E+00 3.4E-01 3.4E-01 1.0E+00 I.OE+O0 1.OE+00 1.0E+00 I.OE+00
1. OE+00 1.0E+00 1.OE+00 1.OE+00
5. lE-01 3.4E-01 3.4E-01 5.7E-01 5.7E-01 > 1.0E+00 1.OE+00 1.0E+00 1.0E+00 3.4E-01 3.4E-01 3.4E-01 1.OE+00 1.OE+00 1.OE+00 3.4E-01 > 1.2E-01 3.4E-01 1.OE+00 1.0E+00 1.0E+00 3.4E-01 4.OE-02 4.E-02 4.OE-02 4.OE-02
4. OE-02 4.E-02
      • forced Minarick 04-11-1987 16:57:59 Event Identifier: 324/84-014 D-119
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