ML20168A725
| ML20168A725 | |
| Person / Time | |
|---|---|
| Site: | Robinson  |
| Issue date: | 06/16/2020 |
| From: | Christopher Hunter NRC/RES/DRA/PRB |
| To: | |
| Littlejohn J (301) 415-0428 | |
| References | |
| LER 1971-057-00 | |
| Download: ML20168A725 (4) | |
Text
PRECURSOR DESCRIPTION AND DATA NSIC Accession Number:
63144 Date: April 7, 1971
Title:
Both Diesels Fail to Start at Robinson 2 The failure sequence was:
- 1. Due to a history of set point drift in the diesel generator low lube oil pressure switches, the switches were replaced with switches con-sidered more reliable. To reduce the effects of vibration on the new switches, the switches were mounted on the room walls and connected to the diesels using approximately 15' of 1/4" copper tubing.
- 2. During subsequent testing, both diesels failed to run due to low indi-cated lube oil pressure at the pressure switches, a result of trapped air and high viscosity cold lube oil In the small tubing, which pre-vented transmission of the correct oil pressure to the pressure switches.
Corrective action:
The pressure switch lines were replaced with 3/8" tubing which included a vent connection.
Design purpose of failed system or component:
The diesel generators provide power to safety related loads in the event of unavailability of the unit generator and offsite power sources.
Unavailability of system per WASH 1400:
Emergency power: 1 x 10- 2/1)
Unavailability of component per WASH 1400:
Diesel generator:
3 x 10-2/D Umavailabilities are in units of per demand D-'.
Failure rates are in units of per hour HR-1.
Reactor Both Diesel Generators at Power Fail to Start Due to and Diesel Improperly Sized and Generator Vented Hydraulic Lines Testing in Between the Diesel Lube Progress Oil System and Low Lube Oil Pressure Switches Potential Severe Core Damage No -
No loss of offsite power No NSIC 63144 -
Actual Occurrence for Both Diesel Generator Fail to Start at Robinson 2
Loss of Offsite Power Turbine Generator Runs Back and Assumes House Loads Emer-gency Power Auxiliary PORV Feedwater and Demanded Secondary Heat Removal PORV or PORV Isola-tion Valve Closure High Pressure Inj ection Long Term Core Cooling Potential Severe Core Damage No Sequence No.
2 3
4 5
6 7
8 9
10 11 12 13 NSIC 63144 -
Sequence of Interest for Both Diesel Generators Fail to Start at Robinson 2
- mot included in mitigation procedures
CATEGORIZATION OF ACCIDENT SEQUENCE PRECURSORS NSIC ACCESSION NUMBER:
63144 DATE OF LER: April 7, 1971 DATE OF EVENT:
March 8, 1971 SYSTEM INVOLVED:
Emergency power COMPONENT INVOLVED:
Diesel generator low lube oil pressure switches CAUSE:
Incorrect hydraulic connection between switches and lube oil system
.SEQUENCE OF INTEREST:
Loss of off site power ACTUAL OCCURRENCE:
Diesel generator failure to start during testing REACTOR NAME:
Robinson 2 DOCKET NUMBER: 50-261 REACTOR TYPE:
PWR DESIGN ELECTRICAL RATING:
700 MWe REACTOR AGE:
.43 yr VENDOR:
Westinghouse ARCHITECT-ENGINEERS:
Ebasco OPERATORS:
Carolina Power & Light Co.
LOCATION:
5 miles.NW of Hartsville, SC DURATION:
360(a) hours PLANT OPERATING CONDITION:
At power (level unspecified)
SAFETY FEATURE TYPE OF FAILURE:
a)inadequate performance; (b) failed to start; made inoperable; (d)
DISCOVERY METHOD:
Testing COMMENT-/