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Entered date | Event description | |
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ENS 44646 | 8 November 2008 09:06:00 | Planned maintenance activities are being performed today (November 8, 2008) on the Hatch Nuclear Plant's 1C 4160V Bus (1R22-S003) Frame 5 under work order number 1041640301. The planned work will remove power from 1R24-SO34 and 1R24-SPO60 which will affect the Unit 1 Service Building and Unit 2 Service Building Annex. This will deenergize power to the Primary Operations Support Center (OSC) rendering the OSC non-functional. (TRM - Section T 3.10.1 EMERGENCY RESPONSE FACILITIES) during the performance of this work activity. The specific work is to replace the breaker in frame 5 of 1C 4160V Bus (1R22-S-003) and perform routine preventative maintenance on 1R24-S034 and 2R24-S050 (Work Order # 1041641101) while they are de-energized to minimize future out of service time. This work activity is planned to be performed expeditiously and will be completed within 10 hours. If an emergency were to occur, it is estimated that power can be restored in approximately 1 hour. If an emergency condition occurs that requires activation of the OSC, the Alternate OSC in the Simulator Building will be used in accordance with plant procedure 73EP-EIP-021-0, Alternate Operations Support center (OSC) Activation, until power is restored. This event is reportable per 10CFR50.72(b)(3)(xiii) as described in NUREG-1022, Rev. 1 since this work activity affects the emergency response facility. The licensee notified the NRC Resident Inspector.
At 1602 EST, power was restored to the OSC Motor Control Center. Notified the R2DO (Widmann). |
ENS 44849 | 12 February 2009 16:56:00 | Unit 2 HPCI (High Pressure Coolant Injection) system is being considered inoperable due to the following information: (Condition Report 2009101257) The instrumentation associated with the automatic suction swap for Unit 2 HPCI was reviewed as a result of CR 2009100480 to confirm the set points that determine the condensate storage tank (CST) level at which the suction swap would occur. During the course of this review, the corporate design engineer contacted the level switch vendor to review the configuration of the level switches and to confirm the expected operation of the switches (2E41-N002 & 2E41-N003) given their configuration. Based on the configuration of the instrument lines and physical location of the level switches, the vendor reported that either liquid or gas would most likely be entrapped in the external cage of the Magnetrol level switches. This would prevent the instruments from performing their automatic swap function. Based on this information the 'as found' condition of the switches indicate that this condition has been present since the installation of the switches when implementing the DCP in 1991 which affects the operability of this instrumentation. Even though the suction swap instrumentation on low CST level is considered inoperable, there is no apparent actual adverse impact on nuclear safety. However, the instrumentation is included in the Technical Specifications and its inoperability would make HPCI inoperable if it is aligned to the CST rather than being aligned to the suppression pool. The normal system alignment is with its suction source to the CST, therefore HPCI is being considered as inoperable. Until the configuration of the level switches has been addressed, these Magnetrol level switches must be considered inoperable, the appropriate Technical Specification RAS (Required Action Statement) will be entered and the suction source for HPCI should be aligned to the suppression pool when HPCI is required to be operable. This condition only applies to Unit 2. The licensee has notified the NRC Resident Inspector.
Event Report 44849 Retraction: On February 12, 2009, a condition was discovered where the physical location of level switches relied upon for automatically transferring the suction of the Unit 2 high pressure coolant injection (HPCI) system from the condensate storage tank (CST) to the suppression pool on low CST level did not meet the setpoints given in the Technical Specifications. Based on the information available at that time HPCI would have to be considered inoperable based on the fact that the affected instrumentation was inoperable and with HPCI aligned to the CST. Since the unit was shutdown HPCI was not required to be operable. After further review the determination has been made that at the time of discovery the 'as found' plant configuration associated with the suction swap setpoint for the Unit 2 high pressure coolant injection (HPCI) system could NOT have prevented the fulfillment of the safety function since the unit was in Cold Shutdown, and HPCI was not required to be operable. Based on this information this condition did not require an NRC notification in accordance with I0CFR50.72 and as such is being retracted through this update response. The condition will be reported in accordance with I0CFR50.73(a)(2)(v), The licensee has notified the NRC Resident Inspector. Notified R2DO (Sykes) |