ML20147A342
| ML20147A342 | |
| Person / Time | |
|---|---|
| Site: | Beaver Valley |
| Issue date: | 06/19/1981 |
| From: | Christopher Hunter NRC/RES/DRA/PRB |
| To: | |
| Littlejohn J (301) 415-0428 | |
| References | |
| LER 1981-047-00 | |
| Download: ML20147A342 (4) | |
Text
PRECURSOR DESCRIPTION AND DATA NSIC Accession Number:
166650 Date:
June 19, 1981
Title:
Safety Injection Supply Valve Found Unlocked and Closed at Beaver Valley The failure sequence was:
- 1. With the reactor at full
- power, the primary auxiliary building operator discovered the normally locked-open emergency cooling water supply valve to the safety injection pumps unlocked and closed.
Corrective action:
- 1.
The valve was reopened and locked in that position.
Design purpose of failed system or component:
The high head safety injection pumps provide water for RCS makeup following a small break LOCA.
Reactor at Primary auxiliary building full power operator discovers emergency cooling water supply valve unlocked and closed, resulting in unavailability of the high head safety injection trains Potential Severe Core Damage i
No - no requirement for safety injection during period of time system was unavailable Possible -
if SI had been required before closed valve had been opened NSIC 166650 - Actual Occurrence for Safety Injection Supply Valve Found Unlocked and Closed at Beaver Valley
Small Reactor Auxiliary High Low Pressure LOCA Trip Feedwater and Pressure Recirculation Secondary Injection and LPR/HPI Heat Removal Cross-Connect Potential Severe Core Damage Sequence No.
No Yes Yes 2
3 No 4
Yes Yes Yes 5
6 7
NSIC 166650 -
Sequence of Interest for Safety Injection Supply Valve Found Unlocked and Closed at Beaver Valley
CATEGORIZATION OF ACCIDENT SEQUENCE PRECURSORS NSIC ACCESSION NUMBER:
166650 LER NO.:
81-047 DATE OF LER:
June 19, 1981 DATE OF EVENT:
June 6, 1981 SYSTEM INVOLVED:
High pressure safety injection COMPONENT INVOLVED:
Suction valve CAUSE:
Normally locked open valve found closed SEQUENCE OF INTEREST:
LOCA ACTUAL OCCURRENCE:
Unavailability of high head SI systems REACTOR NAME:
Beaver Valley DOCKET NUMBER:
50-334 REACTOR TYPE:
PWR DESIGN ELECTRICAL RATING:
852 MWe REACTOR AGE:
5.35 years VENDOR:
Westinghouse ARCHITECT-ENGINEERS:
Stone and Webster OPERATORS:
Duquesne Light Co.
LOCATION:
5 miles east of East Liverpool, Ohio DURATION:
4.62 h PLANT OPERATING CONDITION:
Full power TYPE OF FAILURE:
Made inoperable DISCOVERY METHOD: Operator observation COMMENT:
(1) On June 5,
- 1981, the utility also discovered the chains used to lock the normally open emergency feedwater valves were missing and could not be found.
Those valves were in their correct positions.
(2)
Additional information:
Report to Congress on Abnormal Occurrences, NUREG-0090, Vol.
4, No.
3.