ML20168A554
| ML20168A554 | |
| Person / Time | |
|---|---|
| Site: | Hatch  |
| Issue date: | 06/16/2020 |
| From: | Christopher Hunter NRC/RES/DRA/PRB |
| To: | |
| Littlejohn J (301) 415-0428 | |
| References | |
| LER 1976-088-00 | |
| Download: ML20168A554 (4) | |
Text
PRECURSOR DESCRIPTION AND DATA NSIC Accession Number:
120293 Date:
November 11, '1976
Title:
Plant Service Water Strainers Plug at Hatch 1 The failure sequence was:
- 1. While operating at 85% power, both division I and II service water strainers plugged, thus reducing the plant service water to the turbine and Reactor building. The strainer drive motors had failed.
Corrective action:
The strainers were manually back flushed twice per shift until the drive motors were repaired.
Design purpose of failed system or component:
the drive motors power the pumps that keep the service water strainers clean.
Unavailability of system per WASH 1400: *High Pressure Service Water:
1.1 X 1lO4 Unavailability of component per WASH 1400: *Pumps failure to run:
3 x lO-5IHr Unavailabilities are in units of per demand D-1.
Failure rates are in units of per hour 1R-1.
Reactor Operating Operator Receives an Strainers are Manually Backflushed at 85% Power Alarm that Both Serý-.
Twice Per Shift Until Motors are vice Water Strainers Repaired are Plugged Potential Severe Core Damage No No No NSIC 120293 -
Actual Occurrence of Plant Service Water Strainers Plug at Hatch 1
Loss of Reactor jOffsite Scram Power I
Diesel Start and Load Reactor Made Sub-critical by the SBLCS Or Rods Are Manually Driven In RCIC/HPCI ADS/LPCI Long Potential Initiates CS Trerm Severe Initiates Core Core Cooling Damage r
No Yes No Yes Yes No (C 0)
Yes Yes No Yes No Yes Yes Yes Yes Sequence No.
1 2
3 4
5 6
7 8
9 10 11 12 13 14 15 NSIC 120293 -
Sequence of Interest of Plant Service Water Strainers Plug at Hatch 1
CATEGORIZATION OF ACCIDENT SEQUENCE PRECURSORS NSIC ACCESSION NUMBER: 120293 DATE OF LER: November 11, 1970 DATE OF EVENT:
Unknown SYSTEM INVOLVED:
Service Water COMPONENT INVOLVED:
Strainers CAUSE: Plugging SEQUENCE OF INTEREST: 'LOOP ACTUAL OCCURRENCE:
Plant Service Water Strainers Plug at Hatch 1 REACTOR NAME:
Hatch 1 DOCKET NUMBER: 50-321 REACTOR TYPE:
BWR DESIGN ELECTRICAL RATING:
777 ilWe REACTOR AGE:
2.2 yr VENDOR:
General Electric ARCHITECT-ENGINEERS:
Southern Services OPERATORS:
Georgia Power LOCATION:
Eleven miles N of Baxley, GA DURATION:
12.(a) hours PLAN~T OPERATING CONDITION:
85%
SAFETY FEATURE TYPE OF FAILURE: (,W,,inadequate performance; (b) failed to start; Q)ade inoperable; (d)_____________
DISCOVERY METHOD:
COMMENT: