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On 4/28/01 at 2101 hours, a main generator … On 4/28/01 at 2101 hours, a main generator field ground annunciator was received due to a Stator Water System leak and actions were taken to remove the main generator from service at 2323 hours. Following generator removal/turbine trip, the main condenser vacuum degraded and was determined non-recoverable. A manual reactor scram was inserted by procedure at 0050 hours, on 4/29/01. Following insertion of the reactor scram, as a result of one turbine steam bypass valve, which stuck one half open for four minutes, invalid Division 2 Emergency Closed Cooling System (ECCS) actuation signals were received on a combination of low sensed level and high pressure signals. Then shortly after MSIV closure at 0249 hours, during the first of a series of manual SRV operations for controlling pressure, an invalid Division 3 ECCS actuation signal was received. Though the signals were invalid, all systems responded as designed to their logic actuation. Also in response to the Division 3 actuation signal, the High Pressure Core Spray System pump was over-ridden off in accordance with plant procedures. Subsequently, the A and B loops of Residual Heat Removal were required by procedure to be placed in suppression pool cooling mode of operation as a result of SRV operations. This resulted in entry into Technical Specification 3.0.3, "Limiting Condition for Operation Applicability.</br></br>The cause of the loss of vacuum was a process error that resulted in two moisture separator drain tank manways being improperly torqued during the recent refueling outage and becoming unseated when the pressure was reduced in the tank following the turbine removal from service. The cause of the reactor level/pressure actuations was determined to be localized flashing and pressurization of the sensing lines in the affected instrument reference legs.</br></br>The stator water cooling lines were repaired. The affected manways were re-worked, gaskets repaired and the remaining manways were properly retorqued; RPV level instrument reference legs were filled and vented, and operators were provided with awareness briefings and lessons learned from the event.</br></br>This event is being reported in accordance with the requirements of 10CFR50.73(a)(2)(iv), as a condition that resulted in multiple specified system actuations, and 10CFR50.73(a)(2)(i)(B), as a condition prohibited by the plant's Technical Specifications.d by the plant's Technical Specifications.
April 29, 2001 +
On 4/28/01 at 2101 hours, a main generator … On 4/28/01 at 2101 hours, a main generator field ground annunciator was received due to a Stator Water System leak and actions were taken to remove the main generator from service at 2323 hours. Following generator removal/turbine trip, the main condenser vacuum degraded and was determined non-recoverable. A manual reactor scram was inserted by procedure at 0050 hours, on 4/29/01. Following insertion of the reactor scram, as a result of one turbine steam bypass valve, which stuck one half open for four minutes, invalid Division 2 Emergency Closed Cooling System (ECCS) actuation signals were received on a combination of low sensed level and high pressure signals. Then shortly after MSIV closure at 0249 hours, during the first of a series of manual SRV operations for controlling pressure, an invalid Division 3 ECCS actuation signal was received. Though the signals were invalid, all systems responded as designed to their logic actuation. Also in response to the Division 3 actuation signal, the High Pressure Core Spray System pump was over-ridden off in accordance with plant procedures. Subsequently, the A and B loops of Residual Heat Removal were required by procedure to be placed in suppression pool cooling mode of operation as a result of SRV operations. This resulted in entry into Technical Specification 3.0.3, "Limiting Condition for Operation Applicability.</br></br>The cause of the loss of vacuum was a process error that resulted in two moisture separator drain tank manways being improperly torqued during the recent refueling outage and becoming unseated when the pressure was reduced in the tank following the turbine removal from service. The cause of the reactor level/pressure actuations was determined to be localized flashing and pressurization of the sensing lines in the affected instrument reference legs.</br></br>The stator water cooling lines were repaired. The affected manways were re-worked, gaskets repaired and the remaining manways were properly retorqued; RPV level instrument reference legs were filled and vented, and operators were provided with awareness briefings and lessons learned from the event.</br></br>This event is being reported in accordance with the requirements of 10CFR50.73(a)(2)(iv), as a condition that resulted in multiple specified system actuations, and 10CFR50.73(a)(2)(i)(B), as a condition prohibited by the plant's Technical Specifications.d by the plant's Technical Specifications.
Has query"Has query" is a predefined property that represents meta information (in form of a <a rel="nofollow" class="external text" href="https://www.semantic-mediawiki.org/wiki/Subobject">subobject</a>) about individual queries and is provided by <a rel="nofollow" class="external text" href="https://www.semantic-mediawiki.org/wiki/Help:Special_properties">Semantic MediaWiki</a>.
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1 +
Modification date"Modification date" is a predefined property that corresponds to the date of the last modification of a subject and is provided by <a rel="nofollow" class="external text" href="https://www.semantic-mediawiki.org/wiki/Help:Special_properties">Semantic MediaWiki</a>.
04:40:44, 1 December 2017 +
June 14, 2001 +
April 29, 2001 +
Feedwater +, Service water +, Reactor Protection System +, Main Steam Isolation Valve +, Reactor Core Isolation Cooling +, Shutdown Cooling +, Reactor Recirculation Pump +, Reactor Pressure Vessel +, High Pressure Core Spray +, Residual Heat Removal +, Reactor Water Cleanup +, Stator Cooling Water +, Stator Water +, Safety Relief Valve +, Moisture Separator Reheater +, Main Condenser + and Low Pressure Coolant Injection +
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