ML20168A436
| ML20168A436 | |
| 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 1973-002-00 | |
| Download: ML20168A436 (4) | |
Text
PRECURSOR DESCRIPTION AND DATA NSIC Accession Number:
85738 Date:
Title:
RCIC and HPCI Failure During Testing at Browns Ferry 1 The failure sequence was:
- 1. Duriiig startup testing the RCIC system failed to operate when manually imit'ated.
The steam supply valve faL.ed to open,
- 2. HPCI.was then manually initiated to maintain vessel water level.
However, it isolated and tripped.
- 3. The operator reset the isolation circuit and reinitiated HPCI which operated successfully.
Corrective action:
- 1. The RCIC steam supply valve was repaired.
- 2. No cause for the HPCI trip could be found.
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:
- RCIC 8.0 x 10-2 /D HPic 8.8 x 10 2 /1)
Unavailability of component per WASH 1400:
- Unavailabilities are in units of per demand D-1.
Failure rates are in units of per hour HRR'.
Startup Testing Was RCIC Becames Inoperable When HPCI Successfully Injected ADS and Low Pressure waterwa Was d Lo edt ito Openm Supl Veseai sWael Aftother i eats r Initialucesfu Underwa Wand Feed-its StaO SplyVlen Fail sWaer intor ithe Re itactr SsesScesu Failure to Start Potential Severe Core Damage No No Yes No NSIC 85738 -
Actual Occurrence of RCIC and HPCI Failure During Testing at Browns Ferry 1
Potential Severe Core Damage Sequence No.
No I
Yes 2
No yes Yes 5
Yes 6
Yes 7
NSIC 85738 -
Sequence of Interest for RCIC and HPCI Failures During Testing at Browns Ferry 1
'An apparent loss of feedwater.
2PIwas manually reset and operated satisfactorily.
CATEGORIZATION OF ACCIDENT SEQUENCE PRECURSORS NSIC ACCESSION NUMBER: 85738 DATE OF LER: November 19, 1973 DATE OF EVENT:
SYSTEM INVOLVED:
RCIC/HPCI COMPONENT INVOLVED:
Steenm supply valve, Isolation circuits CAUSE:
Mechanical Failure SEQUENCE OF INTEREST:
Loss of Feedwater ACTUAL OCCURRENCE:
HPCI and RCIC Failures during testing.
REACTOR NAME:
Browns Ferry 1 DOCKET NUMBER:
259 REACTOR TYPE:
BWR DESIGN ELECTRICAL RATING: 1065 MWe' REACTOR AGE:
.18 yr VENDOR:
General Electric ARCHITECT-ENGINEERS:
TVA OPERATORS:
TVA LOCATION:
10 miles NW of Decatur, AL DURATION:
N/A PLANT OPERATING CONDITION:
Start up testing SAFETY FEATURE TYPE OF FAILURE:
(a) inadequate performance; 6failed to start; (c) made inoperable; (d)
DISCOVERY METHOD: Operational Event while startup testing.
COMMENT: No LER