ML20149K348
| ML20149K348 | |
| Person / Time | |
|---|---|
| Site: | Haddam Neck File:Connecticut Yankee Atomic Power Co icon.png |
| Issue date: | 05/28/2020 |
| From: | Christopher Hunter NRC/RES/DRA/PRB |
| To: | |
| Littlejohn J (301) 415-0428 | |
| References | |
| LER 1981-003-00 | |
| Download: ML20149K348 (4) | |
Text
Accession Number: 165900 e: April 21, 1981 Inadvertent Opening of Pressurizer Relief Valve at Haddam Neck failure sequence was:
With the reactor at 100% power, pressurizer PORV PR-SOV-570 and its block valve PR-MOV-569 opened spuriously due to a connector coming loose from pressure controller PC 401/3.
This resulted in an RCS pressure decrease from 2000 to 1980 psi.
rective action:
The connector was reinstalled. Actuation logic for the PORV and block valve were modified from a one channel pressure signal to 2 out of 3 channels to prevent spurious actuations.
gn purpose of failed system or component:
The PORV provides overpressure protection for the RCS and prevents lenges to the code safety valves.
opening of PORV PR-SOV-570 before event Core and block valve PR-MOV-569 terminated Damage No - incident ter-minated prior to significant RCS blowdown No No 165900 - Actual Occurrence for Inadvertent Opening of Pressurizer Relief Valve and Block Valve at Haddam Neck
Heat Removal Cross-Connect Damage No 1 Yes 2 Yes 3 No 4 Yes 5 Yes 6 Yes 7 NSIC 165900 - Sequence of Interest for Inadvertent Opening of Pressurizer Relief Valve and Block Valve at Haddam Neck
O.: 81-003 OF LER: April 21, 1981 OF EVENT: April 3, 1981 INVOLVED: Pressurizer relief NENT INVOLVED: PORV and block valve
- Loose electrical connector caused spurious signal NCE OF INTEREST: Small break LOCA L OCCURRENCE: Small break LOCA OR NAME: Haddam Neck T NUMBER: 50-213 OR TYPE: PWR ELECTRICAL RATING: 580 MWe OR AGE: 13.7 years R: Westinghouse TECT-ENGINEERS: Stone and Webster TORS: Conn Yankee Atomic Power Co.
ION: 13 miles east of Meriden, Connecticut ION: N/A OPERATING CONDITION: 100% power OF FAILURE: Inadvertent opening ERY METHOD: Operational event NT: