ML20168A595
| ML20168A595 | |
| Person / Time | |
|---|---|
| Site: | Peach Bottom  |
| Issue date: | 06/16/2020 |
| From: | Christopher Hunter NRC/RES/DRA/PRB |
| To: | |
| Littlejohn J (301) 415-0428 | |
| References | |
| LER 1977-037-00 | |
| Download: ML20168A595 (4) | |
Text
PRECURSOR DESCRIPTION AND DATA NSIC Accession Number:
131225 Date:
August 28, 1077
Title:
Two Diesel Generators Fail to Start at Peach Bottom 2 The failure sequence was:
- 1. During loss of offsite power test diesel El failed to start and diesel E4 failed to run after starting.
- 2. The problem with El was traced to jacket temperature alarm which had tripped in high jacket temperature during previous actuation.
The service water pump supplying the jacket had tripped on thermal overl-oad.
The problem had been detected prior to the test, however, due to human oversight, it was not corrected.
- 3. An investigation showed that diesel E-4 tripped on overspeed. The over-speed mechanism had been installed improperly after maintenance during which the camshaft was replaced.
The necessary shims for the overspeed mechanism were not replaced.
This resulted in improper operation of the overspeed mechanism.
Corrective action:
- 1. The operators were reminded through a letter about the requirement to reset the diesel trips and alarms, after investigating the alarm.
Design purpose of failed system or component:
- 1. Emergency Power provides power when offsite power is unobtainable.
- 2. The overspeed mechanisms trip the diesel when it overspeeds.
- 3. The jacket alarm prevents the diesel from overheating.
Unavailability of system per WASH 140 0Q.Emergency Power:
10-3 1D Una vailability of component per WASH l40Q:*Diesel Engine Failure to start:
3:10 JD Diesel Engine Failure to run:
- 3. 10 4 /Hr Unavailabilities are in units of per demand D-1.
Failure rates are in units of per hour HRR'.
A Loss Of Offsite Diesel E-1 Failed To Start Diesel E-4 Tripped After Power Test Was Due To A Tripped Jacket Starting Due To A Failed Underway Temperature Alarm Overspeed Trip Potential Severe Core Damage No, reactor in cold shutdown No No No NSIC 131225 -
Actual Occurrence of Two Diesel Generators Fail at Peach Bottom 2
Loss of Reactor Diesel Reactor Made Sub-RCIC/HPCI ADS/LPCI Long Powier Sca Loartad SBcSrica Rod Are Innitia CS TesCre Poffier Sra Startad ScSrica byd the Initiates CsoTer i
IManually Driven In Cooling Potential Severe Core Damage Sequence No.
No Yes No Yes Yes No Yes Yes No Yes No Yes Yes Yes Yes 1
2 3
4 5
6 7
8 9
10 11 12 13 14 15 NSIC 131225 -
Sequence of Interest for Two Diesel Generators Fail to Start at Peach Bottom 2
'Resetting the jacket temperature alarm would result in a success.
2Proper loading of the operating diesels would allow success of alternate shutdown procedures or systems.
CATEGORIZATION OF ACCIDENT SEQUENCE PRECURSORS NSIC ACCESSION NUMBER: 131225 DATE OF LEE:
September 9, 1977 DATE OF EVENT: August 26, 1977 SYSTEM INVOLVED: Emergency Electric Power COMPONENT INVOLVED: Diesel Generators CAUSE:
Humana oversight, Improper Maintemance & Procedures.
SEQUENCE OF INTEREST: Loss of Of fsite Power.
ACTUAL OCCURRENCE:
Two Diese1a Fail to Start REACTOR NAMIE:
Peach Bottom 2 DOCKET NUMBER:
50-277 REACTOR TYPE:
BWR DESIGN ELECTRICAL RATING: 1065 MWe REACTOR AGE: 3.9 yr VENDOR:
General Electric ARCHITECT-ENGINEERS:
Bechtel OPERATORS: Philadelphia Electric Company LOCATION:
19 miles S of Lancaster DURATION:
360(a) hours PLAN~T OPERATING CONDITION:
0% power SAFETY FEATURE TYPE OF FAILURE:
(ainadequate performance; (b) failed to start;
(~made inoperable; (d)____________
DISCOVERY METHOD:
Test CONN1ENT: