ML20147A470
| ML20147A470 | |
| Person / Time | |
|---|---|
| Site: | Brunswick  |
| Issue date: | 05/26/2020 |
| From: | Christopher Hunter Office of Nuclear Regulatory Research |
| To: | |
| Littlejohn J (301) 415-0428 | |
| References | |
| LER 1981-039-00 | |
| Download: ML20147A470 (4) | |
Text
PRECURSOR DESCRIPTION AND DATA NSIC Accession Number:
166082 Date:
May 7, 1981
Title:
Loss of RCIC and HPCI Systems at Brunswick 2 The failure sequence was:
- 1.
At approximately 37% power, during performance testing, the HPCI system injection valve failed to open due to burned windings in the valve motor operator.
- 2.
The HPCI system was declared inoperable.
- 3.
During subsequent testing of RCIC, a faulty resistor in the RCIC turbine governor controls caused a loss of speed control, followed by an overspeed trip, making the RCIC system inoperable.
- 4.
Both HPCI and RCIC systems were inoperable.
Corrective action:
- 1.
The faulty HPCI valve motor operator, which was found to have burned windings, was replaced, tested satisfactorily, and returned to service.
- 2.
A thorough investigation of the HPCI failed motor windings did not reveal cause for the failure.
- 3.
The faulty RCIC resistor was replaced, and the system was tested satisfactorily and returned to service.
Design purpose of failed system or component:
- 1. RCIC provides reactor water level makeup following trip when the feedwater system is unavailable.
- 2.
HPCI provides reactor core cooling in the event of a small break LOCA.
HPCI test is HPCI injection valve RCIC found inoperative under way with fails to open due to due to failed resistor reactor at burned motor windings, in turbine governor 37% power resulting in HPCI inoperability Potential Severe Core Damage No -
no requirement for HPCI, RCIC No No NSIC 166082 - Actual Occurrence of Loss of RCIC and HPCI Systems at Brunswick 2
Loss of Reactor Standby RCIC/HPCI Automatic LPCI or ng Feedwater Scram Liquid
Response
Depressurization CS Response Term Flow Control Adequate System Operates Adequate Core Initiatedl I
Cooling Potential Severe Core Damage Sequence No.
No Yes 1
No Yes Yes Yes 2
3 4
5 6
No 7
Yes Yes Yes 8
9 10 NSIC 166082 -
Sequence of Interest for Loss of RCIC and HPCI at Brunswick 2
CATEGORIZATION OF ACCIDENT SEQUENCE PRECURSORS NSIC ACCESSION NUMBER:
166082 LER NO.:
81-039 DATE OF LER:
May 7, 1981 DATE OF EVENT:
April 10, 1981 SYSTEM INVOLVED:
HPCI and RCIC COMPONENT INVOLVED:
Valve operator and turbine governor CAUSE:
Mechanical failures SEQUENCE OF INTEREST:
LOFW ACTUAL OCCURRENCE:
HPCI and RCIC found inoperable upon testing REACTOR NAME:
Brunswick 2 DOCKET NUMBER:
50-324 REACTOR TYPE:
BWR DESIGN ELECTRICAL RATING:
821 MWe REACTOR AGE:
6.1 years VENDOR:
General Electric ARCHITECT-ENGINEERS:
United Engineers & Constructors OPERATORS:
Carolina Power & Light LOCATION:
3 miles north of Southport, North Carolina DURATION:
360 h (estimated)
PLANT OPERATING CONDITION:
37% power TYPE OF FAILURE:
Failed to start; made inoperable DISCOVERY METHOD:
Surveillance testing COMMENT:
Additional information:
NSIC 166083 (Brunswick 2, 50-324, LER 81-029, May 5, 1981).