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| Entered date | Event description | |
|---|---|---|
| ENS 40325 | 17 November 2003 09:35:00 | This report is being made pursuant to 10CFR50.72(b)(3)(v)(D), Event or Condition that could have prevented fulfillment of a Safety Function needed to mitigate the consequences of an Accident. During performance of scheduled surveillance test LIS-HP-310, Reactor Vessel High Water Level 8 (High Pressure Core Spray) HPCS Injection Valve Closure Instrument Channels A and B Functional Test, Instrument Maintenance personnel discovered one end of fuse 1B21A-F8 not fully seated. The other end of the fuse was fully seated, and was maintaining the un-clipped end in sufficient contact with the fuse holder to complete the circuit. Had the circuit been deenergized, a Control Room annunciator (1H13-P601 A404) would have alarmed, and High Pressure Core Spray (HPCS) automatic low level initiation circuits would have been disabled. The fuse was fully seated without incident. Upon discovery of the unseated fuse, the initial operability determination concluded that adequate contact was maintained to keep the circuit OPERABLE. After followup evaluation by Engineering, it was determined that continued OPERABILITY could not be assured during a seismic event. Failure of this fuse would prevent automatic actuation of HPCS on reactor vessel level low 2; and would prevent automatic closure of the HPCS discharge valve 1E22-F004 on reactor vessel level high 8. This would prevent the HPCS system, a single train safety system, from performing its design function during a Loss of Coolant Accident subsequent to a seismic event. This is reportable as an 8 hour ENS notification." The licensee informed the NRC Resident Inspector. |