05000281/LER-2005-001
| Docket Numbersequential Rev Month Day Year Year Month Day Yearnumber No. 05000 | |
| Event date: | 04-01-2005 |
|---|---|
| Report date: | 06-24-2005 |
| Reporting criterion: | 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications 10 CFR 50.73(a)(2)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident |
| 2812005001R00 - NRC Website | |
1.0 DESCRIPTION OF THE EVENT On April 26, 2005 at 0230 hours0.00266 days <br />0.0639 hours <br />3.80291e-4 weeks <br />8.7515e-5 months <br />, while performing an engineered safety feature actuation test with Unit 2 in cold shutdown, breaker 24J-3 [EIIS-ED, BKR] for Low Head Safety Injection (LHSI) pump 1B [EIIS-BP, P] failed to close when a simulated automatic closure signal was generated with the breaker in the test position.
Following the failure to close during the actuation test, the breaker also failed to close when the Main Control Room (MCR) switch was placed in the closed position and when the local close pushbutton on the breaker was depressed. The breaker was inspected while still in the test position and it was noted that the coil spring was charged and there was no overcurrent trip bell lockout at the breaker. A manual close lever was used to successfully close the breaker. The breaker was opened from the MCR and the closing spring charged as designed. A second attempt to close the breaker from the MCR failed.
Technical Specification 3.3 requires that two safety injection subsystems be operable, with each subsystem including one operable low head safety injection pump, when a reactor is made critical. During power operation, the requirements may be modified to allow one LHSI subsystem to be inoperable for 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />. An evaluation considered the breaker to have been inoperable since the previous successful test on April 1, 2005, exceeding the allowed outage time of 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />.
Therefore, this report is submitted in accordance with 10CFR50.73(a)(2)(i)(B) for any operation or condition that was prohibited by Technical Specifications. In addition, Technical Specification 1.0 definition for operable requires all necessary emergency electrical power sources that are required for a device to perform its specified function(s) are also capable of performing their related support function(s).
However, the emergency diesel generator for the redundant LHSI pump 1A was inoperable related to testing and maintenance from April 23, 2005 at 0856 hours0.00991 days <br />0.238 hours <br />0.00142 weeks <br />3.25708e-4 months <br /> for less than 19 hours2.199074e-4 days <br />0.00528 hours <br />3.141534e-5 weeks <br />7.2295e-6 months <br />. Therefore, this report is submitted in accordance with 10CFR50.73(a)(2)(v)(D) for any event or condition that could have prevented the fulfillment of the safety function of structures or systems that are needed to mitigate the consequences of an accident.
2.0 SIGNIFICANT SAFETY CONSEQUENCES AND IMPLICATIONS Surry Unit 2 has two subsystems of safety injection that are used to remove heat from the reactor core. Each subsystem includes one high head charging pump [EIIS-BQ, P], and one low head safety injection pump. There are two independent and redundant LHSI pumps with their discharges cross connected so that either pump is capable of providing safety injection to the reactor coolant system. The as found condition of circuit breaker 24J-3 resulted in the inability of the breaker to