ML20168A738
| ML20168A738 | |
| Person / Time | |
|---|---|
| Site: | Trojan File:Portland General Electric icon.png |
| Issue date: | 06/16/2020 |
| From: | Christopher Hunter NRC/RES/DRA/PRB |
| To: | |
| Littlejohn J (301) 415-0428 | |
| References | |
| LER 1979-003-00 | |
| Download: ML20168A738 (4) | |
Text
B-607 PRECURSOR DESCRIPTION AND DATA NSIC Accession Number:
149250 Date:
April 14, 1979
Title:
Two Main Steam Isolation Valves Fail to Close at Trojan The failure sequence was:
- 1. With the reactor in hot standby, main steam isolation valve testing was in progress.
- 2. Two of the main steam isolation valves failed to close when manually initiated due to binding between the valve stem and packing.
Corrective action:
- 1. The valve packings were adjusted so the valves operated freely.
Design yurpose of failed system or component:
The main steam isolation valves isolate the steam generators during a steam line break, and prevent blowdown of more than one steam generator.
Unavailability of system per WASH 1400:*-
Unavailability of component per WASH 1400: *valve, failure to operate:
1l-3 Unavailabilities are in units of per demand D-1.
Failure rates are in units of per hour HR'1
Reactor in Hot Main Steam Isolation Standby and Main Valves CV-2256 and Steam Isolation CV-2276 Fail to Close Valve Testing Due to Binding Between~
_____________I Packing Potential Severe Core Damage No -
No steam line break to 00 NSIC 149250 -
Actual Occurrence for Two Main Steam Isolation Valves Fail to Close at Trojan
Steam Reactor Steam Auxiliary High PORV Opened PORV or Long Line Trip Generator Feedwater and Pressure Due to Con-PORV Isola-Term Break Isolation Secondary Injection tinued HPI tion Valve Core Heat Removal Closure Cooling Potential Severe Core Damage
-No No
-Yes
-No Sequence No.
2 3
4 Possible (with worst case stuck rod)
No 5
6
%0 Yes Yes Yes Yes 7
8 9
10 NSIC 149250 -
Sequence of Interest for Two Main Steam Isolation Valves Fail to Close at Trojan
B-610 CATEGORIZATION OF ACCIDENT SEQUENCE PRECURSORS NSIC ACCESSION NUMBER:
149250 DATE OF LER:
April 27, 1979 DATE OF EVENT:
April 14, 1979 SYSTEM INVOLVED:
Main steam COMPONENT INVOLVED:
Main steam isolation valves CAUSE:
Valves failed to close due to binding between valve stem-and packing.
SEQUENCE OF INTEREST:
Steam line break ACTUAL OCCURRENCE:
Valve failed to close during testing.
REACTOR NAME:
Trojan DOCKET NUMBER:
50- 344 REACTOR TYPE:
PWR DESIGN ELECTRICAL RATING:
1130 MWe REACTOR AGE:
3.3 yr VENDOR:
Westinghouse ARCHITECT-ENGINEERS:
Bechtel OPERATORS:
Portland General Electric Co.
LOCATION:
42 miles north of Portland, Oregon DURATION:
360(a) hours PLANT OPERATING CONDITION:
Hot standby SAFETY FEATURE TYPE OF FAILURE: 0 inadequate performance; (b) fat-fed to start; (c) made inoperable; (d)
DISCOVERY METHOD:
During testing.
COMMENT:
I