05000272/LER-2014-005
| Salem Generating Station - Unit 1 | |
| Event date: | 08-27-2014 |
|---|---|
| Report date: | 10-21-2014 |
| Reporting criterion: | 10 CFR 50.73(a)(2)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident |
| 2722014005R00 - NRC Website | |
0001, or by Internet e-mail to Infocollects.Resource@nrc.gov, and to the Desk Officer, Office of Information and Regulatory Affairs, NEOB-10202, (3150-0104), Office of Management and Budget, Washington, DC 20503. If a means used to impose an information collection does not display a currently valid OMB control number, the NRC may not conduct or sponsor, and a person is not required to respond to, the information collection.
01-2014)
CONTINUATION SHEET
2. DOCKET 6. LER NUMBER 3. PAGE 1. FACILITY NAME Salem Generating Station — Unit 1 05000272
PLANT AND SYSTEM IDENTIFICATION
Westinghouse - Pressurized Water Reactor (PWR/4) High-Pressure Safety Injection System {BQ/ - } Medium Voltage Power System- Class lE {EB/ - } Low-Pressure Safety Injection System {BP/ - } DC Power Systems {E..1/ -} Reactor Coolant System {AB/ - } Energy Industry Identification System (EllS) codes and component function identifier codes appear as {SS/CCC}.
IDENTIFICATION OF OCCURRENCE
Event Date: August 27, 2014 Discovery Date: August 27, 2014
CONDITIONS PRIOR TO OCCURRENCE
Salem Unit 1 was in operational Mode 1, operating at 100 percent rated thermal power. No additional structures, systems or components were inoperable at the time of discovery that contributed to this event.
DESCRIPTION OF OCCURRENCE
On August 27, 2014, the 11 Safety Injection (SI) pump {BQ/P} was being tagged and removed from service for planned maintenance. At 0243, the 11 SI pump was declared inoperable when its 4 kV supply breaker {EB/52}, 125 VDC Control Power was removed. The plant entered TS 3.5.2, b., ACTION a. for inoperability of one Emergency Core Cooling System (ECCS) subsystem. TS 3.5.2, ACTION a. states that the inoperable ECCS subsystem shall be restored to OPERABLE status within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> or the unit be in HOT SHUTDOWN within the following 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />.
At 0248, operators were attempting to fill the 14 SI Accumulator {BP/ACC} using the 12 SI pump, when the 12 SI pump failed to start on demand. TS 3.0.3 was entered for inoperability of two ECCS subsystems. TS 3.0.3 requires that when a Limiting Condition for Operation is not met except as provided in the associated ACTION requirements, within one hour, the unit shall be in at least HOT STANDBY within the next 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />, at least HOT SHUTDOWN within the following 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />, and at least COLD SHUTDOWN within the subsequent 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.
An 8-hour report was made to the NRC at 0913 under the requirements of 10 CFR 50.72(b)(3Xv) for "Any event or condition that could have prevented the fulfillment of a safety function of systems that are needed to:...(D) Mitigate the consequences of an accident.
At 0259, the 11 SI pump 4 kV supply 125 VDC control power { EJ/JC} was energized and the pump was considered to be available. At 0301, after a brief test run, the 11 SI pump was declared OPERABLE and the plant exited TS 3.0.3. The unit then remained in TS 3.5.2, b., ACTION a. for inoperability of a single ECCS subsystem. The 12 SI pump breaker was replaced with a recently overhauled breaker. At 1657, the plant exited TS 3.5.2, b, ACTION a. when the 12 SI pump was tested satisfactorily and declared OPERABLE
CAUSE OF OCCURRENCE
The direct cause of the failure of the 12 SI pump to start was due to a failure of the spring release solenoid in the pumps General Electric (GE) 4 kV Magne-Blast Breaker. Investigation identified charring of the spring release solenoid. The contacts of the R-6 relay controlling the spring release solenoid were also fused. Failure analysis is in progress.
PREVIOUS OCCURRENCES
A review of Salem Unit 1 and 2 Licensee Event Reports for the previous three years identified no other similar events.
SAFETY CONSEQUENCES AND IMPLICATIONS
In accordance with Salem Unit 1 Technical Specification 3.5.2, two independent trains of ECCS components are required to be operable in Modes 1, 2 and 3. The Salem Updated Final Safety Analysis Report (UFSAR) assumes that a minimum of one train of ECCS would be available to operate in the event of an accident. The SI pumps provide intermediate range pressure water injection into the Reactor Coolant System (RC) {AB} during the injection, Cold Leg recirculation and Hot Leg recirculation phases of a Loss of Coolant Accident (LOCA). Salem Unit 1 had two trains of ECCS components inoperable for a period of 13 minutes.
There were no actual safety consequences associated with this event. Had there been an accident during this time, operators would have returned the 11 SI pump back to service when performing initial steps in the emergency operating procedures to verify pump operations. Operators appropriately responded by returning the 11 SI pump to service and exiting the condition within 13 minutes. Online risk monitoring indicated that Unit 1's Incremental Core Damage Probability (ICDP) and Incremental Large Early Release Probability (ILERP) values remained in the "Green" status band, not exceeding 1.0 E-6 and 1.0 E-7 respectively for the duration of the event.
This event constitutes a Safety System Functional Failure (SSFF) as defined in Nuclear Energy Institute (NEI) 99-02, Regulatory Assessment Performance Indicator Guideline.
CORRECTIVE ACTIONS
1. The 12 SI pump breaker was replaced with a recently overhauled breaker. The breaker and the pump were tested, and the 12 SI Pump was returned to service.
2. The failed 12 SI pump breaker has been sent to GE for failure analysis.
3. The failed 12 SI Pump breaker R-6 relay has been sent to Exelon PowerLabs for failure analysis.
COMMITMENTS
No commitments are made in this LER.