ML20168A711
| ML20168A711 | |
| Person / Time | |
|---|---|
| Site: | Point Beach  |
| Issue date: | 06/16/2020 |
| From: | Christopher Hunter NRC/RES/DRA/PRB |
| To: | |
| Littlejohn J (301) 415-0428 | |
| References | |
| LER 1971-053-00 | |
| Download: ML20168A711 (4) | |
Text
PRECURSOR DESCRIPTION AND DATA NSIC Accession Number:
65757 Date:
June 30, 1971
Title:
Loss of Offsite Power at Point Beach 1 (Semi-Annual Operations Report for January-June, 1971)
The failure sequence was:
- 1. With the reactor at hot standby during an ice storm, breakers on all three high limes opened (reason unspecified).
- 2. A reactor trip occurred.
- 3. Both diesel generators started and supplied safety-related loads.
- 4. In view of the continuing storm conditions, the reactor coolant system was borated to the cold shutdown level amd cooled down to 3000 F.
Corrective action:
The unit was returned to power two days after the event.
Design purpose of failed system or component:
Offsite power is the preferred source of power to safety related loads when the unit generator is not producing power.
Unavailability of system per WASH 1400: *Loss of offai~te power:
2 x.1075 /hr Unavailability of component per WASH 1400:
N/A Umavailabilities are in units of per demand D-1.
Failure rates are in units of per hour HR-1.
Potential Severe Core Damage No ATU3 S
Yes lo No NSIC 65757 -
Actual Occurrence for Loss of Offsite Power at Point Beach 1.
Loss of Of f site Power Turbine Generator Runs Back and Assumes House Loads Emer-gency Power Auxiliary PORV F
Feedwater and Demanded F
Secondary t
Heat Removal C
(IRV or ORV Isola-ion Valve losure High Long Potential Pressure Term Severe Injection Core Core Cooling Damage No Sequence No.
2 3
4 5
6 7
8 9
10 11 12 13 NSIC 65757 -
Sequence of Interest for Loss of Off site Power at Point Beach I
- Not included in operating procedures
CATEGORIZATION OF ACCIDENT SEQUENCE PRECURSORS NSIC ACCESSION NUMBER:
65757 DATE OF LER: June 30, 1971 DATE OF EVENT: February 5, 1971 SYSTEM INVOLVED: Offsite power COMPONENT INVOLVED: Highline breakers CAUSE: Opened (reason unspecified)
SEQUENCE OF INTEREST:
Loss of offsite power ACTUAL OCCURRENCE: Loss of offsite power REACTOR NAME: Point Beach 1 DOCKET NUMBER: 50-266 REACTOR TYPE: PWR DESIGN ELECTRICAL RATING:
497 MWe REACTOR AGE:
.26 yr VENDOR: Westinghouse ARCHITECT-ENGINEERS: Bechtel OPERATORS: Wisconsin Electric Power Co.
LOCATION: 15,miles nortYh 6f'M~nitowoc, Wisc.
DURATION:
N/A PLANT OPERATING CONDITION: Hot standby SAFETY FEATURE TYPE OF FAILURE:
(a) inadequate performance; (b) failed to start; (9 made inoperable; (d)
DISCOVERY METHOD:
Operational event COMMENT: