ML20168A718
| ML20168A718 | |
| Person / Time | |
|---|---|
| Site: | Quad Cities  |
| Issue date: | 06/16/2020 |
| From: | Christopher Hunter NRC/RES/DRA/PRB |
| To: | |
| Littlejohn J (301) 415-0428 | |
| References | |
| LER 1975-031-00 | |
| Download: ML20168A718 (4) | |
Text
ugust 17, 1975 Low Flow Feedwater Line Severed at 6"1to 4"1 Reducer at Quad Cities e sequence was:
eactor was increasing power after startup.
nsfer was being made from the low flow feed regulating valve to the main regulating valve.
both main and low feed regulating valves partially opened, a feedwater tion alarm was received in the control room.
perator manually scrammed the reactor because the low flow lime -- ad that it was starting to sever.
eedwater pumps were tripped and the feedwater regulating station was isolated.
ximately 11,500 gallons of water was spilled; of this 65% was reactor coolant he remaining 35% was service water.
believed the failure resulted from vibration of the feedwater regulating on during the transfer.
as used to maintain water level control.
action:
4 x 6 reducer fabricated from more ductile steel was installed.
ers were installed to reduce pipe movement.
the main feedwater valves was replaced with a "drag valve" to provide control over a wide spectrum of flow conditions.
pose of failed system or component:
ater system provides feedwater to the reactor.
lity of system per WASH 1400:*
lity of component per WASH 1400:
- Pipe >3" 1 x 10-1 /hr.
ailabilities are in units of per demand D2 Failure rates are in er hour HR-'.
increasing power Operator manually Operator isolates RCIC used to Potential startup and vibra- scrams the reactor feedwater regu- maintain water Severe from feedwater and trips feedwater lating station level control Core ting station induce PUMP Danage reak in 6x4 reducer low flow feedwater No No - HPCI, ADS/LPCI/CS and other feedpump available No - ECCS available No - power conversion system available SIC 105540 - Actual Occurrence of Low Flow Feedwater Line Severed at 6x4 Reducer at Quad Cities 2
No Yes 2
- No 3 Yes 4 "es 5 Yes 6 NSIC 105540 - Sequence of Interest 'for Low Flow Feedwater Line Severed at 6x4 Reducer at Quad Cities 2
N NUMBER: 105540 August 27, 1975
- August 17, 1975 ED: Peedwater OLVED: Piping e rupture NTEREST: Loss of Coolant Accident ENCE: Low Flow Feedwater Line Severed at 6" to 4" Reducer Quad Cities 2
- 50-265 BWR ICAL RATING: 789 MWe 3.3 yr neral Electric INEERS: Sargent & Lundy Commonwealth Edison 0 miles.NE o~fM~oline, Ill.
A G CONDITION: Power accension E TYPE OF FAILURE: (a) inadequate performance; (b) failed to start; (c) made inoperable;Q0 everdd.
HOD: Operational Event