ML20168A565
| ML20168A565 | |
| Person / Time | |
|---|---|
| Site: | La Crosse File:Dairyland Power Cooperative icon.png |
| Issue date: | 06/16/2020 |
| From: | Christopher Hunter NRC/RES/DRA/PRB |
| To: | |
| Littlejohn J (301) 415-0428 | |
| References | |
| LER 1971-001-00 | |
| Download: ML20168A565 (4) | |
Text
PRECURSOR DESCRIPTION AND DATA NSIC Accession Number:
61043 Date:
February 10, 1971
Title:
Plant Electrical Power Failure at LaCrosse The failure sequence was:
- 1. With the reactor shutdown, maintenance was being performed at the Genoa substation.
- 2. Vibration resulting from that maintenance work tripped a protective differential relay, which resulted in a loss of power to the plant 69 KV tie line.
- 3. The diesel started and assumed safety-related loads.
Corrective action:
- 1. The emergency shutdown condenser and emergency core spray pump were used for core cooling.
- 2. Power was restored to the 69 KV tie line 14 minutes later.
- 3. Additional procedures to minimize inadvertant relay actuation during maintenance were initiated.
Design purpose of failed system or component:
- 1. Offsite power provides power to plant safety-related loads when the umit generator is unavailable.
Unavailability of system per WASH 1400:*
,LOOP: 2 x 105 /hr.
Unavailability of component per WASH 1400:*
- I Unavailabilities are in units of per demand D-1.
Failure rates are in units of per hour HLC'.
Reactor shut-Vibration during main-Diesel generator starts, down for tenance at genoa sub-core cooling provided by maintenance station results in emergency core spray Irelay trip and loss of pump and emergency I
off site power shutdown condenser Potential Severe Core Damage 4 W No Possible -
if shutdown condenser and diesel generator is lost No NSIC 61043 -
Actual Occurrence for Plant Electrical Power Failure at La Crosse
Loss of Reactor Diesel Reactor Made Sub-RCIC/HPCI ADS/LPCI Long Powier Loam sartad SBcSrica Rod Are Innitia CS TesCre Pofwier Sra Startad SBcSrica byd the Initiates CSoTer IManually Driven In Cooling Potential
.Severe Core Damage No Yes No Yes Yes No Yes Yes No Yes No Yes Yes Yes Yes Sequence No.
1 2
3 4
5 6
7 8
9 10 11 12 13 14 15 NSIC 61043 -
Sequence of Interset for Plant Electrical Power Failure at La Crosse La Crosse utilizes shutdown condenser and condensate pumps instead of ROIC and HPCI.
CATEGORIZATION OF ACCIDENT SEQUENCE PRECURSORS NSIC ACCESSION NUMBER:
61043 DATE OF LER:
February 10, 1971 DATE OF EVENT:
January 20, 1971 SYSTEM INVOLVED:
offsite power COMPONENT INVOLVED:
relay CAUSE:
inadvertent actuation during maintenance (human error)
SEQUENCE OF INTEREST:
loss of offsite power ACTUAL OCCURRENCE:
loss of of fsite power during shutdown REACTOR NAME:
LaCrosse DOCKET NUMBER:
50-409 REACTOR TYPE:
BWR DESIGN ELECTRICAL RATING:
50 MWe REACTOR AGE:
3.5 yr VENDOR:
Allis-Chalmers ARCHITECT-ENGINEERS:
Sargent & Lundy OPERATORS:
Dairyland Power Cooperative LOCATION:
19 miles S of LaCrosse, Wisc.
DURATION:
N/A PLANT OPERATING CONDITION:
shutdown SAFETY FEATURE TYPE OF FAILURE:
(a)inadequate performance; (b) failed to start; G(c made inoperable; (d)____________
DISCOVERY METHOD:
operational event COMMENT:
-