ML20156A149
ML20156A149 | |
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 1984-010-00 | |
Download: ML20156A149 (5) | |
Text
PRECURSOR DESCRIPTION SHEET LER No.:
265/84-010 Event
Description:
Trip with RCIC Failure Date of Event:
October 25, 1984 Plant:
Quad-Cities 2 EVENT DESCRIPTION Sequence On October 251, 1984, Unit 2 was proceeding to hot standby.' ý`At 0546 h, the procedure, was partially completed, and all outboard MSIVs were closed.
once the outboard MSIVs were closed, reactor pressure started to increase.
In an attempt to control pressure, additional con-trol rods were inserted into the core.
Because the reactor was already subcritical, the insertion of additional rods had no effect on :the increasing pressure.
A second attempt was made to control pressure by starting the RCIC system.
RCIC tripped on overspeed and had to be man-r ually and locally reset at the turbine.
Concurrently, the HPCI system was started by another operator, but the reactor scrammed from a high pressure of 1044 psig at 0641 h.
When the reactor scrammed, rod K-13 remained at position 48.
Con-trol rod K-13 was successfully inserted from the individual rod scram back-panel at 0712 h.
An inspection of the hydraulic control unit 38-51, which drives control rod K-13, revealed that the scram discharge riser valve EP 305-112 was closed, preventing the drive from venting properly when the scram took place.
A thorough investigation to determine the root cause of the manual valve 112 being closed was conducted by reexamining Work Requests, Out-of -Service' requests subsequent to the refueling outage, the September 18 hot scram timing surveillance tests, accumulator alarms logged in the unit operator's log book subsequent to the September 18 hot scram surveillance tests, and work performed on CRD modules in the vicinity of that for the K-13 hydraulic control unit (on both units).
Despite all of the above measures, the reason for valve EP 305-112 being in the improper position could not be determined.
Corrective Action The LER stated that the procedure for placing the plant in hot standby from full power would be revised.
The hydraulic control unit valve positions were checked.
The RCIC problem was being investigated at the time of the report.
Event Identifier:
265/84"-010 D-57
Plant/Event Data Systems Involved:
RC IC Components and Failure Modes Involved:
RCIC -
tripped on demand Component Unavailability Duration:
NA Plant Operating Mode:
3 (0% power)
Discovery Method:
Operational event Reactor Age:
12.5 years Plant Type:
BWR Comments None MODELING CONSIDERATIONS AND DECISIONS Initiators Modeled and Initiator Nonrecovery Estimate Transient 1.0 No recovery Branches Impacted and Branch Nonrecovery Estimate RCIC
- 0134, Recoverable locally at pump Plant Models Utilized.
BWR plant Class C Event Identifier:
2,65/84-010, D-58
CONDITIONAL CORE DAMIAGE PROBABILITY CALCULATIONS Event Identifier: 265/84-010 Event
Description:
Trip with RCIC Failure Event Date:
10/25/84 Plant:
Quad Cities 2
.INITIATING EVENT NON-RECOVERABLE INITIATING EVENT PROBABILITIES TRANS SEQUENCE CONDITIONAL PROBABILITY SUMS End State/Initiator 1.OE+O0 Probability CV Total 1.2E-07 1.2E-07 CD TRANS Total 8.9E-06 8.9E-06 ATWdS TRANS Total 2.OE-05 2.OE-05 DOMINANT SEGLENS End State:
CV Conditional Probability:
7.8E-08 134 TRANS SCRAM -SLC.OR.RDDS PCS/TRANS -SRV.CLOSE FW/PCS.TRANS HPCI RCIC/TRANS.OR.L0OP -SRV.ADS
End State:
CD Conditional Probability:
7.11-06 101 TRANS -SCRAM PCS/TRANS SRV.CHALL/TRANS.-SCRAtI -SRV.CLOSE -FW/PCS.TRANS RHR(SDC)
RHR(SPCOOL) /
C.I.AND.V/RHR(SDC).RHR(SPCOOL)
Event Identifier: 265/84-010 D-59
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
C.1.AND.
V/RHR(SDC).RHR(SPCOOL) 102 TRANS -SCRAM PUS/TRANS SRV.CHALL/TRANS.-SCRAM -SRV.CLOSE FW
C.
I.AND.V/RHR(SDC).RHR(SPCOOL) 110 TRANS -SCRAM PCSITRANS SRV.CHALL/TRANS.-SCRAM -SRV.CLOSE FW
/PCS.TRANS HPCI RCIC/TRANS.OR.LOOP CR0 SRV.ADS 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) 138 TRANS SCRAM -SLC.OR.RODS PUS/TRANS -SRV.CLOSE FW/PCS.TRANS HPCI RCIC/TRANS.OR.LOIJP -SRV.ADS COND/FW.PCS -LPCS -RHR(
SDC) 173 TRANS SCRAM SLC.OR.RODS CD CD CD Cv CV 7.1E-06 *
.1E-01 7.3E-07 3-8E-02 7.4E-07 6.6&-02 7.8E-08 4.3&-02 4.OE-08 2.2E-02 2.OE-05 1.0E+00 ATWS
- dominant sequence for end state
- non-recovery credit for edited case MODEL:
DATA:
b :\\bwrctree.cmp b
- \\qcprob.clup No Recovery Limit BRANCH FREQUENCIES/PROBABILITIES Branch TRANS LOOP LOCA SCRAM SLC.OR.RODS PCS/TRANS PCS/LOCA SRV.CHALL/TRANS.-SCRAM BRY.CHALL/TRANS.SCRAM SRV.CHALL/LOOP.-SCRAM SRV.CHALL/LOOP.SCRAM SR V
.CLOSE EMERS.PObJER FW/PCS.TRANS System 1.1E-03 1.3E-05 3.3E-06
- 4. 1 E-04
- 1. OE-02 1.7E-01 1.0E+00 1,0E+00 1.0E+00 1.0E+00 1.OE+0O 1.6E-02 2.9E-03 2
.9E-01 Non-Recov 1.0E+00 3.4E-01 3.4E-01 1.0E+00 1.0E+00 1.0E+00 1.0E+00 1.0E+00 1.0E+00 1.0E+00 1.OE+00 1.0E+00 5.1E-01 3
.4E-01 Opr Fail 4
.E-02 Event Identifier: 265/84-010 D-60
FW/PCS.LOCAi HPCI RCIC/TRANS.OR.LOOP Branch Model: INAF.
Train I Cond Prob:
RCIC/LfJCA
':CRD SRV.ADS COND/FW.PCS LPCS LPCI (RR) /LPCS
.,RHRSW/LPCS.LPCI.TRANS RHRSW/LPCS.LPCI.LOOP RHRSW/LPCS.LPCI.LOCA kRHR (SDC)
RHR(SDC) /-LPCI RHR(SBC)/LPCI RHR (SPCOOL) /-LPCI.RHR (SDC)
C.I.AND.V/RHR(SDC).RHR(SPCOaL) 4 OE-02 1.OE-O1 6.7E-02 ) 1.OE+00 6.7E-02 > Failed 1
.OE+OO 1
.OE-02 6.7E-03 1.OE+00 3.OE-03 4 OE-04
.5.OE-O1 5.OE-01 5.OE-O1 2.OE-02 2.OE-02 1.OE+0O 2
.OE-02 5.2E-01 1.OE+OO 3A.E-OI 5.7E-01 5.7E-01 > 3.4E-01 1
.OE+OO I.OE+0O I.OE+OO 3.4E-O1 3.4E-O1 3A.E-O1 1.OE+OO I.OE+OO 1.OE+OO 3.4E-01 3.4E-O1 1.OE+00 L.OE+OO I.OE+00 3.4E-O1 4
.OE-02 4 OE-02 4.OE-02
- 4. OE-02 4.OE-02 forced Minarick 0'4-11-19B7 14:15S: 07 Event Identifier: 265/84-010 D-61