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On 03/08/2001 at 0306 EST, Unit 2 was in t … On 03/08/2001 at 0306 EST, Unit 2 was in the Run mode at a power level of 2763 CMWT (100 percent rated thermal power). At that time, the supply breaker to Unit 2 emergency 600-volt bus "2C" opened on a false over-current signal. As a result, Reactor Protection System (RPS) bus "2A" lost power. Logic systems powered by the RPS bus include the RPS trip logic, the Main Control Room Environmental Control System (MCRECS) initiation logic, Primary Containment Isolation System (PCIS) trip logic, and Steam Packing Exhauster trip logic. All affected systems responded per design on the loss of power, producing a half scram signal, several PCIS valve isolations, MCRECS pressurization mode initiation, and other actuations. In addition, the "A" subsystems of the Core Spray, Residual Heat Removal (RHR) containment spray, RHR suppression pool spray, and RHR service water systems were rendered inoperable.</br></br>By 0540 EST, personnel had re-energized 600-volt bus "2C" and returned affected safety-related systems to their normal lineups.</br></br>The cause of the supply breaker trip was a poor work practice causing personnel calibrating an over-current relay to short two trip contacts in the relay case, generate a false over-current signal, and trip the bus supply breaker. Corrective actions included revising calibration procedures to eliminate the poor work practice.dures to eliminate the poor work practice. +
March 8, 2001 +
On 03/08/2001 at 0306 EST, Unit 2 was in t … On 03/08/2001 at 0306 EST, Unit 2 was in the Run mode at a power level of 2763 CMWT (100 percent rated thermal power). At that time, the supply breaker to Unit 2 emergency 600-volt bus "2C" opened on a false over-current signal. As a result, Reactor Protection System (RPS) bus "2A" lost power. Logic systems powered by the RPS bus include the RPS trip logic, the Main Control Room Environmental Control System (MCRECS) initiation logic, Primary Containment Isolation System (PCIS) trip logic, and Steam Packing Exhauster trip logic. All affected systems responded per design on the loss of power, producing a half scram signal, several PCIS valve isolations, MCRECS pressurization mode initiation, and other actuations. In addition, the "A" subsystems of the Core Spray, Residual Heat Removal (RHR) containment spray, RHR suppression pool spray, and RHR service water systems were rendered inoperable.</br></br>By 0540 EST, personnel had re-energized 600-volt bus "2C" and returned affected safety-related systems to their normal lineups.</br></br>The cause of the supply breaker trip was a poor work practice causing personnel calibrating an over-current relay to short two trip contacts in the relay case, generate a false over-current signal, and trip the bus supply breaker. Corrective actions included revising calibration procedures to eliminate the poor work practice.dures to eliminate the poor work practice. +
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05:01:51, 1 December 2017 +
April 30, 2001 +
March 8, 2001 +
Secondary containment +, Service water +, Reactor Protection System +, Emergency Diesel Generator +, Primary Containment Isolation System +, Primary containment +, Reactor Recirculation Pump +, Core Spray +, Residual Heat Removal +, Reactor Water Cleanup +, Standby Gas Treatment System +, Containment Spray + and Low Pressure Coolant Injection +
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