ML20168A444
| ML20168A444 | |
| Person / Time | |
|---|---|
| Site: | Brunswick  |
| Issue date: | 06/16/2020 |
| From: | Christopher Hunter NRC/RES/DRA/PRB |
| To: | |
| Littlejohn J (301) 415-0428 | |
| References | |
| LER 1979-089-00 | |
| Download: ML20168A444 (4) | |
Text
PRECURSOR DESCRIPTION AND DATA NSIC Accession Number:
153810 Date:
November 20, 1979
Title:
ROIC Turbine Trips with HPCI Unavailable at Brunswick 2 The 1.
2.
3.
4.
5.
failure sequence was:
Reactor trip occurred. (reason unspecified)
HPCI was unavailable due to maintonance.
ROIC initiated on low-low reactor water level (-38 inches).
The RCIC turbine tripped on overspeed.
ROIC was reset and manually set into operation.
The reactor water level had reached -40 inches.
Corrective action:
An investigation revealed a crack in the amphenal connector to the tachometer pickup causing a loose connection.
This connector was replaced and the turbine tested with satisfactory results.
Design purpose of failed system or component:
- 2. The tachometer monitors the turbine speed for control purposes.
Unavailability of system per WASH 1400:
- RCIC:
8 x 10-2/D Unavailability of component per WASH 1400:*-
Unavailabilities are in units of per demand D-1.
Failure rates are in units of per hour HR-1
Potential Severe Core Damage No No -
ADS/CS/LPCI available ahould both HPCI and RCIC fail No No No -
ADS/CS/LPCI available should both HPCI and RCIC fail ATWS I
NSIC 153810 -
Actual Occurrence of RCIC Turbine Trip with H-PCI Unavailable at Brunswick 1
Loss of Reactor RCIC/HPGI Automatic LPCI or Long Feedwater Subcritical
Response
Depressurization CS Response Term Flow Adequate System Operates Adequate Core Cooling Potential Severe Core Damage Sequence No.
No Yes 2
No 3
Yes4 Yes 5
Yes Yes 7
NSIC 153810 -
Sequence of Interest for RCIC Turbine Trip with ff201 Unavailable at Brunswick 1
'Success requires the operator to reset and manually start RCIC.
CATEGORIZATION OF ACCIDENT SEQUENCE PRECURSORS NSIC ACCESSION NUMBER:
153810 DATE OF LER:
December 17, 1979 DATE OF EVENT:
November 20, 1979 SYSTEM INVOLVED:
RCIC COMPONENT INVOLVED:
Tachometer CAUSE:
Mechanical failure SEQUENCE OF INTEREST:
Loss of feedwater flow ACTUAL OCCURRENCE:
RCIC turbine trip with HPCI unavailable REACTOR NAME:
Brunswick 1 DOCKET NUMBER:
50-325 REACTOR TYPE:
BWR DESIGN ELECTRICAL RATING:
821 MWe REACTOR AGE:
3.11 yr VENDOR:
GE ARCHITECT-ENGINEERS:
United Engineers and Constructors OPERATORS:
Carolina Power and Light Co.
LOCATION:
Three miles N of Southport, NC DURATION:
N/A PLANT OPERATING CONDITION: Scrammed SAFETY FEATURE TYPE OF FAILURE:
(a) inadequate performance; (b) failed to start;
~made inoperable; (d) ___________
DISCOVERY METHOD:
operator surveillance COMMENT:
-