ML20168A578
| ML20168A578 | |
| Person / Time | |
|---|---|
| Site: | Nine Mile Point  |
| Issue date: | 06/16/2020 |
| From: | Christopher Hunter NRC/RES/DRA/PRB |
| To: | |
| Littlejohn J (301) 415-0428 | |
| References | |
| LER 1973-LTR-00 | |
| Download: ML20168A578 (4) | |
Text
PRECURSOR DESCRIPTION AND DATA NSIC Accession Number:
86990 Date:
November 17, 1973
Title:
Loss of Incoming Power at Nine Mile Point from a Worker Bumpkng a Relay The failure sequence-was:
- 1. The reactor was shutdown for an AEC operator's examination involving a critical demonstration.
- 2. After the reactor was shutdown, breaker R40 was opened to facilitate, line work on the 115 Ky lime, breaker RlO, the remaining 115 kV line, was closed and the station was operating on reserve power supplied by this line.
- 3. A plant electrician working in the auxiliary control room bumped a relay which caused relay 9 and 5 to de-energize thus trapping the remaining 115 kV lime.
- 4. The plant remained without of fsite power for 10 seconds until break RIO was reclosed.
Corrective action:
The RIO breaker was reclosed within 10 seconds.
Design purpose of failed system or component:
Offaite power supplies house loads when the generator is down.
Unavailability of system per WASH 1400:
LOOP.:
2 x 10-5 /Hr Unavailability of component per WASH 1400:
Unavailabilities are In units of per demand D-1.
Failure rates are in units of per hour 11R-1.
The Reactor Was Shutdown The R40 Breaker Was Open To An Electrician Bumped A Relay The Breaker Was For AEC Operator Facilitate Work On The 115 Causing The Remaining 115 kv Reclosed And Examination kv Line.
Power Was Sup-Line To Trip Power Was Re-plied Through The Remaining stored Within 115 kv Line 10 Sec Potential Severe Core Damage A
j L.
I No No, diesel generator avail-able
.4 No No NSIC 86990 -
Actual Occurrence of Loss of Incoming Power at Nine Mile Point from a Worker Bumping a Relay
Loss of Reactor Diesel Reactor Made Sub-RClC/11PCT ADS/LPCI Long Powrt Sra Loart and C
criica Rod Are Initiates C
o Tre Powfer Sra Start and C
crOia Roy the Initiates CSor[er jManually Driven In Cooling Potential Severe Core Danage 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 86990 -
Sequence of Interest of Loss of Incoming Power of Nine Mile Point from Worker Bumping Relay
CATEGORIZATION OF ACCIDENT SEQUENCE PRECURSORS NSIC ACCESSION NIMhIBER:
86990 DATE OF LER: November 21, 1973 DATE OF EVENT: November 11, 1973 SYSTEM INVOLVED: Off site power COMPONENT INVOLVED:
Breakers CAUSE.
Operator SEQUENCE OF INTEREST: Loss of Offsite Power ACTUAL OCCURRENCE:
Loss of Incoming REACTOR NA.)NE:
Nine Mile Point DOCKET NUJMBER:
220 REACTOR TYPE:
BWR DESIGN ELECTRICAL RATING:
72 MWe REACTOR AGE: 5.2 yr VENDOR: General Electric ARCHITECT-ENGINEERS:
Bechtel OPERATORS:
Consumer Power Corporation LOCATION: -Eight miles NE of Oswego, NY DURATION:
N/A PLANT OPERATING CONDITION:
just critical SAFETY FEATURE TYPE OF FAILURE:
(;a.inadequate performance; (b) failed to start; made inoperable; (d)
DISCOVERY METHOD:
Operational transient CON21ENT; A station blackout loop