ML20156A128
| ML20156A128 | |
| Person / Time | |
|---|---|
| Site: | Perry  |
| Issue date: | 06/04/2020 |
| From: | Christopher Hunter NRC/RES/DRA/PRB |
| To: | |
| Littlejohn J (301) 415-0428 | |
| References | |
| LER 1987-012-00 | |
| Download: ML20156A128 (4) | |
Text
B-175 PRECURSOR DESCRIPTION SHEET LER No.: 440/87-012 Event
Description:
LOFW, trip, and RCIC fails Date of Event: 3/2/87 Plant: Perry 1 EVENT DESCRIPTION Sequence A reactor scram occurred due to low reactor vessel water level caused when operations personnel inadvertently caused a loss of feed-water to the reactor vessel while investigating a condensate system hot surge tank low-level alarm. Following the loss of feedwater, the motor-driven feed pump started, but its control valves locked at minimum flow due to control system problems. The reactor core isolation cooling (RCIC) system failed to initiate because the inboard containment isola-tion steam supply valve failed to open. The high-pressure core spray (HPCS) initiated and supplied water to the reactor vessel. The reactor coolant system cooled down at a rate of 180°F/h for 1 h after the reactor trip. This was 80 degrees above the Technical Specification limit of 100°F/h.
Corrective Action Reactor feed pump trip logic was to be revised to require a low-low level trip in conjunction with a hot surge tank low-level trip. Inves-tigation of the feed pump control problem was continuing at the time of the report.
Plant/Event Data Systems Involved:
Reactor core isolation cooling system Components and Failure Modes Involved:
RCIC failed on demand Component Unavailability Duration: N/A Plant Operating Mode: 1 (28% power)
Discovery Method: Operational event Reactor Age: 0.7 y Plant Type: BWR Comments None.
Event Identifier: 440/87-012
B-176 MODELING CONSIDERATION AND DECISIONS Initiators Modeled and Initiator Nonrecovery Estimate Transient 1.0 No recovery Branches Impacted and Branch Nonrecovery Estimate PCS 1.0 No recovery FW 1.0 No recovery RCIC 1.0 No recovery Plant Models Utilized BWR plant Class C Event Identifier: 440/87-012
B-177 CONDITIONAL CORE DAMAGE PROBABILITY CALCULATIONS Event Identifier: 440/87-012 Event
Description:
LOFW, trip and RCIC fails Event Date: 03/02/87 Plant: Perry 1 INITIATING EVENT NON-RECOVERABLE INITIATING EVENT PROBABILITIES TRANS 1.0E+00 SEQUENCE CONDITIONAL PROBABILITY SUMS End State/Initiator Probability CD TRANS 6.6E-06 Total 6.6E-06 CV 6
TRANS 1.7E-05 Total 1.7E-05 ATWS TRANS 7.0E-06 Total 7.0E-06 SEQUENCE CONDITIONAL PROBABILITIES (PROBABILITY ORDER)
Sequence End State Prob N Rec*-
105 trans -scram PCS/TRANS srv.chall/trans.-scram -srv.close FW/P CD 2.8E-06 1.2E-01 CS.TRANS -hpci rhr(sdc) rhr(spcool)/-Ipci.rhr(sdc) -c.i.and.v rhrsw(c.i.and.v) 145 trans -scram PCS/TRANS srv.chall/trans.-scram srv.close fw/p CD 1. BE-06 8.2E-02 cs.loca hpci srv.ads 125 trans -scram PCS/TRANS srv.chall/trans.-scram -srv.close FW/P CD 1.6E-06 2.4E-01 CS.TRANS hpci RCIC crd srv.ads 106 trans -scram PCS/TRANS srv.chall/trans.-scram -srv.close FW/P CD 1.8E-07 3.4E-01 CS.TRANS -hpci rhr(sdc) rhr(spcool)/-lpci.rhr(sdc) c.i.and.v 127 trans -scram PCS/TRANS srv.chall/trans.-scram srv.close -fw/p CD 1.2E-07 7. 6E-02 cs.loca rhr(sdc) rhr(spcool)/-lpci.rhr(sdc) -c.i.and.v rhrsw(
c.i.and.v) 104 trans -scram PCS/TRANS srv.chall/trans.-scram -srv.close FW/P CV 1.3E-05 2.9E-01 CS.TRANS -hpci rhr(sdc) rhr(spcool)/-lpci.rhr(sdc) -c.i.and.v
-rhrsw(c.i.and.v) 913 trans scram -slc.or.rods PCS/TRANS -srv.close FW/PCS.TRANS h CV 1.4E-06 2.2E-01 pci RCIC -srv.ads -cond/fw.pcs -rhr(sdc) 917 trans scram -slc.or.rods PCS/TRANS -srv.close FW/PCS.TRANS h CV 7.2E-07 1.1E-01 pci RCIC -srv.ads cond/fw.pcs -lpcs -rhr(sdc) 126 trans -scram PCS/TRANS srv.chall/trans.-scram srv.close -fw/p CV 6. OE-07 1. 9E-01 cs.loca rhr(sdc) rhr(spcool)/-lpci.rhr(sdc) -c.i.and.v -rhrsw(
c.i.and.v) 963 trans scram slc.or.rods ATWS 7.OE-06 1.0E+00
- non-recovery credit for edited case SEQUENCE CONDITIONAL PROBABILITIES (SEQUENCE ORDER)
Sequence End State Prob N Rec**
Event Identifier: 440/87-012
B-178 104 trans -scram PCS/TRANS srv.chall/trans.-scram -srv.close FW/P Cv 1.3E-05 2.9E-01 CS.TRANS -hpci rhr(sdc) rhr(spcool)/-lpci.rhr(sdc) -c.i.and.v
-rhrsw(c.i.and.v) 105 trans -scram PCS/TRANS srv.chall/trans.-scram -srv.close FW/P CD 2.8E-06 1.2E-01 CS.TRANS -hpci rhr(sdc) rhr(spcool)/-lpci.rhr(sdc) -c.i.and.v rhrsw(c.i.and.v) 106 trans -scram PCS/TRANS srv.chall/trans.-scram -srv.close FW/P CD 1.8E-07 3.4E-01 CS.TRANS -hpci rhr(sdc) rhr(spcool)/-lpci.rhr(sdc) c.i.and.v 125 trans -scram PCS/TRANS srv.chall/trans.-scram -srv.close FW/P CD 1.6E-06 2.4E-01 CS.TRANS hpci RCIC crd srv.ads 126 trans -scram PCS/TRANS srv.chall/trans.-scram srv.close -fw/p Cv 6.0E-07 1.9E-01 cs.loca rhr(sdc) rhr(spcool)/-lpci.rhr(sdc) -c.i.and.v -rhrsw(
c.i.and.v) 127 trans -scram PCS/TRANS srv.chall/trans.-scram srv.close -fw/p CD 1.2E-07 7.6E-02 cs.loca rhr(sdc) rhr(spcool)/-lpci.rhr(sdc) -c.i.and.v rhrsw(
c.i.and.v) 145 trans -scram PCS/TRANS srv.chall/trans.-scram srv.close fw/p CD 1.8E-06 8.2E-02 cs.loca hpci srv.ads 913 trans scram -slc.or.rods PCS/TRANS -srv.close FW/PCS.TRANS h Cv 1.4E-06 2.2E-01 pci RCIC -srv.ads -cond/fw.pcs -rhr(sdc) 917 trans scram -slc.or.rods PCS/TRANS -srv.close FW/PCS.TRANS h Cv 7.2E-07 1.1E-01 pci RCIC -srv.ads cond/fw.pcs -ipcs -rhr(sdc) 963 trans scram slc.or.rods ATWS 7.0E-06 1.0E+00
- non-recovery credit for edited case SEQUENCE MODEL: c:\asp\newmodel\bwr_cnew.cmp BRANCH MODEL: c:\asp\newmodel\perry.new PROBABILITY FILE: c:\asp\newmodel\bwr_cnew.pro No Recovery Limit BRANCH FRFQUENCIES/PROBABILITIES Branch System Non-Recov Opr Fail trans 8.6E-04 1.0E+00 loop 1.7E-05 3.2E-01 loca 3.3E-06 5.0E-01 scram 3.5E-04 1.0E+00 slc.or.rods 1.OE-02 1.0E+00 1.0E-02 PCS/TRANS 1.7E-01 > 1.0E+00 1.0E+00 Branch Model: I.OF.1 Train 1 Cond Prob: 1.7E-01 > Unavailable srv.chall/trans.-scram 1.0E+00 1.0E+00 srv.chall/loop.-scram 1.0E+00 1.0E+00 srv.close 6.3E-02 1.0E+00 emerg.power 2.9E-03 8.0E-01 ep.rec 1.0E+00 1.7E-01 FW/PCS.TRANS 4.6E-01 > 1.0E+00 3.4E-01 > 1.0E+00 Branch Model: 1.OF.I Train 1 Cond Prob: 4.6E-01 > Failed fw/pcs.loca 1.0E+00 3.4E-01 hpci 2.0E-02 3.4E-01 RCIC 6.0E-02 > 1.0E+00 7.0E-01 > 1.0E+00 Branch Model: l.OF.1 Train 1 Cond Prob: 6.0E-02 > Failed crd 1.0E-02 1.0E+00 1.0E-02 srv.ads 3.7E-03 7.1E-01 1.0E-02 cond/fw.pcs 1.0E+00 3.4E-01 1.0E-03 lpcs 2.0E-02 3.4E-01 lpci(rhr)/lpcs 6.0E-04 7.1E-01 rhr(sdc) 2.3E-02 3.4E-01 1.0E-03 rhr(sdc)/-lpci 2.0E-02 3.4E-01 1.0E-03 rhr(sdc) /lpci 1.0E+00 1.0E+00 1.0E-03 rhr(spcool)/-lpci.rhr(sdc) 2.0E-03 1.0E+00 rhr(spcool)/lpci.rhr(sdc) 5.2E-01 1.0E+00 c.i.and.v 1.0E-03 1.0E+00 1.0E-02 rhrsw 2.0E-02 3.4E-01 2.0E-03 rhrsw(c.i.and.v) 5.0E-01 3.4E-01
- branch model file
- forced Event Identifier: 440/87-012