ML20147A514
| ML20147A514 | |
| Person / Time | |
|---|---|
| Site: | Crystal River  |
| Issue date: | 05/26/2020 |
| From: | Christopher Hunter NRC/RES/DRA/PRB |
| To: | |
| Littlejohn J (301) 415-0428 | |
| References | |
| LER 1981-033-00 | |
| Download: ML20147A514 (4) | |
Text
PRECURSOR DESCRIPTION AND DATA NSIC Accession Number:
167624 Date:
July 14, 1981
Title:
Loss of Offsite Power and Failure of a Diesel Generator to Start at Crystal River 3 The failure sequence was:
- 1.
With the reactor at 100% power, lightning struck the 230 kV feeder line.
- 2.
The lightning arrestor system failed to prevent loss of the CR-3 startup transformer, resulting in loss of all ac power.
- 3.
Diesel generator A started and loaded the A 4169 volt bus.
- 4.
Diesel generator B failed to start due to a maladjusted timing relay.
Power was provided to the B 4180 volt bus from a fossil plant startup transformer via manual connection by the operator.
- 5.
The "B"
DG was successfully started manually about 10 minutes into the transient and was allowed to run on standby until Unit 3 trans-former was energized.
Corrective action:
Offsite power was restored approximately 4-6 h after the loss of offsite power.
The diesel was successfully started about 10 minutes into the transient but was not connected to the buses.
The diesel timing relay was readjusted and incorporated into the surveillance program.
Design purpose of failed system or component:
Offsite power provided the preferred source of power to safety-related loads when the unit generator is unavailable.
The diesel generators provide power to the safety-related buses when both offsite power and the unit generator are unavailable.
Reactor at Failure of Diesel generator Diesel generator Power to 100% power lightning A starts and B fails to start 4160-V bus and lightning arrestor provides power due to maladjusted B provided strike on system to 4160-V bus A timing relay through 230-kV feeder results in loads fossil unit loss of CR-3 startup startup trans-transformer former and LOOP Potential Severe Core Damage No No No No No - turbine driven AFW trains capable of providing core cooling No No NSIC 167624 - Actual Occurrence for Loss of Offsite Power and Failure of a Diesel Generator to Start at Crystal River 3
Loss of Turbine Emer-Auxiliary PORV PORV or High Long Offsite Generator gency Feedwater and Demanded PORV Isola-Pressure Term Power Runs Back Power Secondary tion Valve Injection Core and Assumes_
Heat Removal Closure Cooling House Loads Potential Severe Core Damage Sequence No.
No I
No 2
3 No Yes 4
Yes 5
No 6
No 7
Yes 8
9 Yes No 10 Yes 11 No 12 Yes 13 NSIC 167624 -
Sequence of Interest for Loss of Offsite Power and Diesel Generator Failure to Start at Crystal River 3
CATEGORIZATION OF ACCIDENT SEQUENCE PRECURSORS NSIC ACCESSION NUMBER:
167624 LER NO.:
81-033 DATE OF LER:
July 14, 1981 DATE OF EVENT:
June 16, 1981 SYSTEM INVOLVED:
Offsite power, emergency power COMPONENT INVOLVED:
Startup transformer, diesel generator CAUSE:
Lightning strike resulted in loss of the startup transformer, timing relay maladjustment resulted in diesel failure to start SEQUENCE OF INTEREST:
LOOP ACTUAL OCCURRENCE:
LOOP plus diesel failure to start REACTOR NAME:
Crystal River 3 DOCKET NUMBER:
50-302 REACTOR TYPE:
PWR DESIGN ELECTRICAL RATING:
825 MWe REACTOR AGE:
4.4 years VENDOR:
Babcock & Wilcox ARCHITECT-ENGINEERS:
Gilbert Associates OPERATORS:
Florida Power Corporation LOCATION:
Red Level, Florida DURATION:
N/A PLANT OPERATING CONDITION:
100% power TYPE OF FAILURE:
Failed to start; made inoperable:
DISCOVERY METHOD:
Operational event COMMENT:
See also NSIC 167119 (Crystal River 3, 50-302, LER 81-030, July 1, 1981).