ML20149K390
| ML20149K390 | |
| Person / Time | |
|---|---|
| Site: | La Crosse File:Dairyland Power Cooperative icon.png |
| Issue date: | 05/28/2020 |
| From: | Christopher Hunter NRC/RES/DRA/PRB |
| To: | |
| Littlejohn J (301) 415-0428 | |
| References | |
| LER 1981-002-00 | |
| Download: ML20149K390 (4) | |
Text
PRECURSOR DESCRIPTION AND DATA NSIC Accession Number:
164703 Date:
May 18, 1981
Title:
Loss of offsite power at La Crosse The failure sequence was:
- 1. The reactor was operating at 28% power.
- 2.
The switchyard operator was directed to open a switch in response to another situation, but he opened the wrong switch, disconnecting the auxiliary transformer from the 69 kV transmission line.
This resulted in a loss of all offsite power.
- 3.
The reactor scrammed and the diesel generators started automatically and supplied the required vital loads.
Corrective action:
- 1. Offsite power was restored within 14 min.
- 2.
Practices were revised to require outside switching order to be executed in the presence of a second person whenever possible.
- 3.
Additional practical training was to be provided on the switchyard for all operators.
Design purpose of failed system or component:
Offsite power provides the preferred source of power to plant loads when the unit generator is unavailable.
Reactor operating at Operator switching error Emergency power 28% power disconnecting offsite operates power networks Potential Severe Core Damage No No -
separate diesel-powered service water system avail-able for core cooling No NSIC 164703 - Actual Occurrence for Loop at LaCrosse
Loss of Reactor Diesels Standby One of To One of Four Shutdown HPCS Manual Potential Sequence Offsite Scram Start Liquid HPSW or ESW Condenser Depressuri-Severe
'No.
Power and Load Contro Three of Four zation Core Initiated ESW Damage No I
No 2
No 3
Yes 4
No 5
No 6
Yes 7
No 8
Yes 9
No 10 No 11 Yes 12 No 13 Yes 14 Yes 15 No 16 Yes 18 No 19 No 20 Yes 21 No 22 Yes 23 Yes 24 Yes 25 NSIC 164703 -
Sequence of Interest for LOOP at La Crosse
CATEGORIZATION OF ACCIDENT SEQUENCE PRECURSORS NSIC ACCESSION NUMBER:
164703 LER NO.:
81-002 Rev.
I DATE OF LER:
May 18, 1981 DATE OF EVENT:
February 1, 1981 SYSTEM INVOLVED:
Offsite power COMPONENT INVOLVED:
Switch CAUSE:
Operator error SEQUENCE OF INTEREST:
LOOP ACTUAL OCCURRENCE:
LOOP REACTOR NAME:
La Crosse DOCKET NUMBER:
50-409 REACTOR TYPE:
BWR DESIGN ELECTRICAL RATING:
50 MWe REACTOR AGE:
13.6 years VENDOR:
Allis-Chalmers ARCHITECT-ENGINEERS:
Sargent & Lundy OPERATORS:
Dairyland Power Cooperative LOCATION:
19 miles south of LaCrosse, Wisconsin DURATION:
14 minutes PLANT OPERATING CONDITION:
28% power TYPE OF FAILURE:
Made inoperable DISCOVERY METHOD:
Operational event COMMENT: