ML20168A730
| ML20168A730 | |
| Person / Time | |
|---|---|
| Site: | Salem  |
| Issue date: | 06/16/2020 |
| From: | Christopher Hunter NRC/RES/DRA/PRB |
| To: | |
| Littlejohn J (301) 415-0428 | |
| References | |
| LER 1979-068-00 | |
| Download: ML20168A730 (4) | |
Text
PRECURSOR DESCRIPTION AND DATA NSIC Accession Number:
154286 Date:
November 28, 1979 Titlý:
Safety Injection Pump Fails at Salem 1 The failure sequence was:
- 1. With the reactor in cold shutdown, High Pressure Safety Injection Pump No. 12 was started to refill an accumulator.
- 2. The pump breaker tripped when the pump started.
- 3. investigation revealed the impeller locknuts on the pump had loosened, resulting in worn spacer sleeves and a bent impeller.
- 4. Further investigation revealed the impeller lock nuts on the other High Pressure Injection Pump were also loose, as were the lock nuts on one pump in the other unit.
Corrective action:
The damaged rotating element was temporarily replaced with one from a pump in the other unit.
The lock nuts were secured using Locktite.
Design purpose of failed system or component:
The high pressure injection pumps provide the source of high pressure injec-tion used for loss of coolant accident mitigation.
Unavailability of system per WASH 1400:
- High Pressure Injection (2 of 3 pumps):
1.2 x 10 2 Unavailability of component per WASH 1400:
- Pump, failure to start:
1 x 103'/D Unavailabilities are in units of per demand D-1 Failure rates are in units of per hour HR-1.
Reactor in Cold Shutdown No. 12 Safety Injec-tion Pump Fails to Deliver Flow Due to Loose Impeller Lock Nuts Resulting in Worn Spacer Sleeves and a Bent Impeller Shaft Impeller Lock Nuts Loose on No. 11 Safety Injection Pump Potential Severe Core Damage
¶ No No reactor in cold shutdown plus no LOCA No NSIC 154286 -
Actual Occurrence for Safety Injection Pump Fails at Salem 1
Small Reactor Auxiliary High Low Pressure LOCA Trip Feedwater and Pressure Recirculation Secondary {Injection and LPR/HPI Heat Removal C2ross-Connect Potential Severe Core Damage Sequence No.
2 3
4 5
6 7
NSIC 154286 -
Sequence of Interest for Safety Injection Pump Fails at Salem 1
CATEGORIZATION OF ACCIDENT SEQUENCE PRECURSORS NSIC ACCESSION NUMBER:
154286 DATE OF LER:
December 20, 1979 DATE OF EVENT:
November 28, 1979 SYSTEM INVOLVED:
High Pressure Injection COMPONENT INVOLVED:
High Pressure Injection Pumps CAUSE:
Loose Impeller Lock Nuts SEQUENCE OF INTEREST:
Small LOCA ACTUAL OCCURRENCE:
Failure of ome pumip to deliver flow and loose lock nuts on the other pump while in cold shutdown.
REACTOR NAME:
Salem 1 DOCKET NUMBER:
50-272 REACTOR TYPE:
PWR DESIGN ELECTRICAL RATING:
1090 MW, REACTOR AGE:
3.0 yr VENDOR:
Westinghouse ARCHITECT-ENGINEERS:
PSE&G OPERATORS:
Public Service Electric & Gas Co.
LOCATION-:
20 niles south of Wil-mington, DE DURATION:
360(a) hours PLANT OPERATING COND)ITION:
cold shutdown SAFETY FEATURE TYPE OF FAILURE:
(a) inadequate performance; (b) failed to start; C>made inoperable; (d)
DISCOVERY METHOD:
pump breaker tripped after pump was started.
COMMENT:
High Pressure Injection Pump No. 22 for Salem 2 was also found to have loose impeller locknuts.
Pump 21 for Salem 2 was found to have its lock nuts secured with setscrews.
The pump vendor recommended against this and the pump rotating elements were returned to the pump vendor for rework.