ML20168A438
| ML20168A438 | |
| Person / Time | |
|---|---|
| Site: | Browns Ferry  |
| Issue date: | 06/16/2020 |
| From: | Christopher Hunter NRC/RES/DRA/PRB |
| To: | |
| Littlejohn J (301) 415-0428 | |
| References | |
| LER 1974-LTR-00 | |
| Download: ML20168A438 (4) | |
Text
PRECURSOR DESCRIPTION AND DATA NSIC Accession Number:
95040 Date:
Title:
HPCI Injection Valves and RCIC Fail at Browns Ferry 2 The failure sequence was:
- 1. The HPCI injection valve failed to open during post-maintenance testing of this valve.
- 2. RCIC was then initiated, however, it failed to show any speed indication.
The seat holding the valve operative was broken and a printed circuit board in the tachometer was damaged.
Corrective action:
- 1. The broken valve operator seats were replaced.
- 2. A new circuit board was installed in the RCIC tachometer.
Design purpose of failed system or component:
- 1. RCIC provides a source of water should the reactor become isolated.
Unavailability of system per WASH 1400:*
ROIC: 8.0 x 10-2 /D HPCI: '8.8 x 10 2 /D Unavailability of component per W4ASHI 1400:
NOV *failure to operate: l.Ox 10- 3 /1)
Unavailabilities are in units of per demand D-1.
Failure rates are in units of per hour 1HP?1.
HPCI Test Underway With HPCI Injection Valve RCIC Initiates But Potential The Reactor At 5% Power Fails To Open fTurbine Fails To Severe Develop Speed Core Damage No No No NSIC 95040 -
Actual Occurrence of HPCI Injection Valves and RCIC Fail at Browns Ferry 2
Loss of Reactor RCIC/HPCI Automatic LCI or Long Feedwater Subcritical
Response
Depressurization CS Response Term Flow Adequate System Operates Adequate Core I
Cooling Potential Severe Core Damage Sequence No.
No Yes No 2
3 Yes 4
Yes 5
Yes 6
Yes 7
NSIC 95040 -
Sequence of Interest for HFCI Injection Valves and RCIC Fail at Browns Ferry 2
CATEGORIZATION OF ACCIDENT SEQUENCE PRECURSORS NSIC ACCESSION NUMBER:
95040 DATE OF LER: August 23, 1974 DATE OF EVENT:
SYSTEM INVOLVED: RCFC, HPCI COMPONENT INVOLVED: Valves, tachometer circuit boards.
CAUSE: Mechanical Failure SEQUENCE OF INTEREST: Loss of Feedwater ACTUAL OCCURRENCE: HPCI Injection Valves and RCIC Fail at Browns Ferry 2 REACTOR NAME: Browns Ferry 2 DOCKET NUMBER: 260 REACTOR TYPE:
BWR DESIGN ELECTRICAL RATING: 1065 MWe REACTOR AGE:.09 yr VENDOR:
General 'Electric ARC1HITECT-ENGINEERS: TVA OPERATORS:
TVA LOCATION:
10 miles NW of Decatur, AL DURATION:
360(a) hours PLANT OPERATING CONDITION: operating at 5% power SAFETY FEATURE TYPE OF FAILURE:
(a) inadequate performance; (b) failed to start; O
made inoperable; (d)____________
DISCOVERY METHIOD: Operational Event.
COMMENT: No LER