ML20168A471
| ML20168A471 | |
| Person / Time | |
|---|---|
| Site: | Fort Calhoun  |
| Issue date: | 06/16/2020 |
| From: | Christopher Hunter NRC/RES/DRA/PRB |
| To: | |
| Littlejohn J (301) 415-0428 | |
| References | |
| LER 1978-045-00 | |
| Download: ML20168A471 (4) | |
Text
cember 20, 1978 Both Power Operated Relief Valves (PORVs) Open During Troubleshooting at Fort Calhoun 1 e sequence was:
g a heatup from cold shutdown, one of the two PORV channels failed to respond stem pressure changes.
hnician, while troubleshooting the problem, pulled recorder fuses.
caused both PORVs to open.
perator closed both PORV isolation valves.
action:
the PORVs were being used for NDT overpressure protection, additional istrative controls were established to ensure an overpressure condition not occur.
m modifications to prevent reoccurrence were being considered.
pose of failed system or component:
g normal operation, the PORVs provide relief protection for the RCS and nt lifting the pressurizer safety valves during pressure transients.
g cold shutdown, the PORVs provide NDT overpressure protection.
lity of system per WASH 1400:* -
lity of component per WASH 1400: relief valve, imadvertant opening:
1 x 10 5 '/hr ailabilities are in units of per demand D- . Failure rates are in er hour HR-1 .
shooting of PORV Fuses Damage Pressure Channel No L
I.___No - reactor in cold shutdown
[N40
[NO No 145209 - Actual Occurrence for Both Power Operated Relief Valves Open During Troubleshooting alhoun 1
Heat Removal Cross-Connect Damage 2
3 4
5 6
7 NSIC 145209 - Sequence of Interest for Both Power Operated Relief Valves Open During Troubleshooting Fort Calhoun 1 initiating evemt requires operator failure to close PORV isolation valves.
ON NUMBER: 145209 January 2, 1979 T: December 20, 1978 VED: reactor coolant VOLVED: power operated relief valves nician error in pulling recorder fuses during troubleshooting resulted in PORVs failing open, human error INTEREST: two stuck open PORVs RENCE: two stuck open PORVs during cold shutdown Fort Calhoun 1
- 50-285 PtWR RICAL RATING: 457 MWe 5.5 yr GINEERS: Gibbs & Hill, Inc.
Omaha Public Power District 9 -miles north of Omnaha,.Nebraska
/A NG CONDITION: Cold shutdown E TYPE OF FAILURE: (a) inadequate performance; (b) failed to start; (c) made inoperable; 0 failed open HOD: During operation