ML20168A442
| ML20168A442 | |
| Person / Time | |
|---|---|
| Site: | Brunswick  |
| Issue date: | 06/16/2020 |
| From: | Christopher Hunter NRC/RES/DRA/PRB |
| To: | |
| Littlejohn J (301) 415-0428 | |
| References | |
| LER 1977-054-00 | |
| Download: ML20168A442 (5) | |
Text
PRECURSOR DESCRIPTION AND DATA NSIC Accession Number:
128569 Date:
July 15, 1977
Title:
Safety Relief Valve Fails to Reset at Brunswick 2 The failure sequence was:
- 1. A turbine trip occurred which resulted in a reactor scram.
- 2. HPCI and RCIC initiated and injected into the *reactor causing a level increase and subsequent HPCI and RCIC trip on high water level.
- 3. Safety relief valves were opened three times to maintain the reactor, pressure below 1050 psig.
On the third opening the valve failed to close.
- 4. RCIC was started and injected to the reactor in an attempt to recover reactor vessel level.
It was of insufficient capacity so APC1 was also started and the level was recovered.
- 5. (See next page)
Corrective action:
The grounded solenoid was rewired and retaped Design purpose of failed system or component:
The safety relief valves are designed to control reactor pressure.
Unavailability of system per WASH 1400:
Unavailability of close:' 10-2 /D component per WASH 1400:
Relief Valve failure to
- Unavailabilities are In units of per demand D-1.
Failure rates are in units of per hour 1HR1.
The Failure sequence was: (Continued)
- 5. The division IRHR system was placed in service to cool the torus.
- 6. The reactor pressure decreased from 1050,to 280 in 14 minutes corresponding to a cool down rate of 136F*/hr.
- 7. The valve failed to reset because the solenoid assembly was grounded.
A Reactor Scram Occurred HPCI/RCIC Initiated And Injected Safety Relief Valves Were ROTC Was Manually Potential Following A Turbine Trip Into The Corej They Tripped Once Used To Control Pressure.
Initiated But Was Severe Water Level Was Recovered The "B" Safety Relief Insufficient To Core Valve Stuck Open On The Maintain Water Damage Third Opening Level.
HPCI Was Then Initiated And Water Level Was Again Re-stored No No, ADS/LPCI/CS were operable No No, ADS/LPCI/CS were operable NSIC 128569 -
Actual Occurrence of Safety Relief Valve Fails to Reseat at Brunswick 2
Loss of Reactor IIPCI/RCIC ADS/LPCI Long Coolant Maintained
Response
CS Term Accident Subcritical Adequate
Response
Core Adequate Cooling Potential Severe Core Damage Sequence No.
No 1.
Yes 2
3 No Yes Yes Yes 4
5 6
NSIC 128569 -
Sequence of Interest for Safety Relief Valve Fails to Reset at Brunswick 2
CATEGORIZATION OF ACCIDENT SEQUENCE PRECURSORS NSIC ACCESSION NUMBER:
128569 DATE OF LER: August 3, 1977 DATE OF EVENT:
July 15, 1977 SYSTEM INVOLVED:
Pressure Relief COM4PONENT INVOLVED:
CAUSE:
Safety Relief Valve SEQUENCE OF INTEREST:
Loss of Coolant Accident ACTUAL OCCURRENCE:
Safety Relief Valve Fails to Reset.
REACTOR NAME:
Brunswick 2 DOCKET NUMBER:
324 REACTOR TYPE:
BWR DESIGN ELECTRICAL RATING: 821 MWe REACTOR AGE:
2.4 yr VENDOR:
G.E.
ARCHITECT-ENGINEERS:
United Engineers OPERATORS: Carolina Power and Light LOCATION: Three miles N of Southport DURATION:
N/A PLAN~T OPERATING CPNDITION:
Reactor Scram from 75%/ Power SAFETY FEATURE TYPE OF FAILURE:
inadequate performance; (b) failed to start; Q:3 made inoperable; (d)____________
DISCOVERY METHOD:
Operation Event COM!MENT: