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On August 18, 2008, at 2152 hours Eastern … On August 18, 2008, at 2152 hours Eastern Daylight Time (EDT), during the performance of surveillance OPT-12.14.L, "Diesel Generator 4 Local Control Operability Test," Emergency Diesel Generator (EDG) 4 failed to start from the local control panel. The biennial (i.e., every 24 months) surveillance is a non-Technical Specification (TS) related test to demonstrate that control and indication for EDG 4, and the EDG 4 to Bus E4 output breaker, can be isolated from the Control Room and be controlled from the respective local control station, as required by the Alternate Safe Shutdown (ASSD) analysis. Troubleshooting determined that the Lockout Control Relay (LOCR), installed in a 2007 plant modification, was wired such that power was lost when the associated ASSD switch was in the LOCAL position, ' preventing EDG 4 to be reset so that it could be started locally. The plant modification was installed on all four EDGs, and it has been concluded that this condition impacted the ability of EDG Nos. 2, 3, and 4 to perform their intended ASSD function (i.e., local control of EDG 1 is not credited in the ASSD analysis). This condition did not affect the TS operability of the EDGs and they remained fully capable of performing their intended safety system functions.</br></br>Two root causes were determined for this event; a latent organizational weakness existed where the EDG control wire circuitry maintained the same wire segment number on either side of the ASSD key-switches, and a lack of sufficient rigor by Engineering in performance of their responsibilities during activities associated with modification of control logic circuitry. The corrective actions to prevent recurrence include generating an Engineering Change package to clearly denote on applicable plant drawings that duplicate wire numbers exist on either side of the EDG ASSD key switches, revising the applicable plant drawings, revising respective Engineering procedures, and addressing other factors affecting rigor and risk management during design and review activities.'ment during design and review activities.'
August 18, 2008 +
On August 18, 2008, at 2152 hours Eastern … On August 18, 2008, at 2152 hours Eastern Daylight Time (EDT), during the performance of surveillance OPT-12.14.L, "Diesel Generator 4 Local Control Operability Test," Emergency Diesel Generator (EDG) 4 failed to start from the local control panel. The biennial (i.e., every 24 months) surveillance is a non-Technical Specification (TS) related test to demonstrate that control and indication for EDG 4, and the EDG 4 to Bus E4 output breaker, can be isolated from the Control Room and be controlled from the respective local control station, as required by the Alternate Safe Shutdown (ASSD) analysis. Troubleshooting determined that the Lockout Control Relay (LOCR), installed in a 2007 plant modification, was wired such that power was lost when the associated ASSD switch was in the LOCAL position, ' preventing EDG 4 to be reset so that it could be started locally. The plant modification was installed on all four EDGs, and it has been concluded that this condition impacted the ability of EDG Nos. 2, 3, and 4 to perform their intended ASSD function (i.e., local control of EDG 1 is not credited in the ASSD analysis). This condition did not affect the TS operability of the EDGs and they remained fully capable of performing their intended safety system functions.</br></br>Two root causes were determined for this event; a latent organizational weakness existed where the EDG control wire circuitry maintained the same wire segment number on either side of the ASSD key-switches, and a lack of sufficient rigor by Engineering in performance of their responsibilities during activities associated with modification of control logic circuitry. The corrective actions to prevent recurrence include generating an Engineering Change package to clearly denote on applicable plant drawings that duplicate wire numbers exist on either side of the EDG ASSD key switches, revising the applicable plant drawings, revising respective Engineering procedures, and addressing other factors affecting rigor and risk management during design and review activities.'ment during design and review activities.'
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