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{{#Regex_clear:The purpose of this report … {{#Regex_clear:The purpose of this report is to provide a telephone notification for an invalid actuation. On March 24, 2012, following the completion of switch yard work, the Control Room received switching orders to open Bus Tie 9-10 Bus 9 disconnect and close Bus Tie 9-10 Bus 10 disconnect. Operations was unaware that a grounding device, installed for personnel protection during the work activities, had not been removed. Consequently, when the Bus Tie 9-10 Bus 10 disconnect was closed the switchyard was grounded resulting in an electrical transient. Protective relaying operated as designed to clear the fault, and there were no injuries.</br>During the electrical transient, the voltage depression tripped the Unit 1 "A" Reactor Protection System (RPS) bus which caused a 1/2 scram and certain protective logic systems to de-energize by design. The following invalid actuations occurred as a result of the loss of power to the RPS bus: partial Group 11 Isolation (Primary Containment); Group III Isolation (Reactor Water Cleanup); Reactor Building Ventilation Isolation; Control Room Ventilation Isolation; and Standby Gas Treatment Initiation.</br>The electrical transient also tripped the Unit 1 ECCS keep�fill pump, resulting in the Core Spray (CS) discharge pressure decreasing to the alarm setpoint. Both CS subsystems were conservatively declared inoperable and entry into Technical Specifications (TS) 3.0.3 occurred at 1936 hours. Subsequent fill and vent activities confirmed no air existed in the discharge headers of the CS subsystems (no loss of safety function) and both subsystems were declared operable with TS 3.0.3 being exited at 2017 hours. Following the electrical transient, the Unit 1 generator was temporarily limited to approximately 90% load due to elevated vibration on Turbine Bearing No. 10. In-plant walk-downs identified no other equipment concerns. Unit 1 returned to full power on April 2, 2012, following confirmation the bearing vibration is acceptable for long-term operation. Unit 2 was in a scheduled refueling outage during the event and was unaffected by the electrical transient. A Root Cause Investigation is ongoing.</br>The licensee notified the NRC Resident Inspector. }}ee notified the NRC Resident Inspector. }}
00:36:00, 25 March 2012 +
47,875 +
13:38:00, 30 April 2012 +
00:36:00, 25 March 2012 +
{{#Regex_clear:The purpose of this report … {{#Regex_clear:The purpose of this report is to provide a telephone notification for an invalid actuation. On March 24, 2012, following the completion of switch yard work, the Control Room received switching orders to open Bus Tie 9-10 Bus 9 disconnect and close Bus Tie 9-10 Bus 10 disconnect. Operations was unaware that a grounding device, installed for personnel protection during the work activities, had not been removed. Consequently, when the Bus Tie 9-10 Bus 10 disconnect was closed the switchyard was grounded resulting in an electrical transient. Protective relaying operated as designed to clear the fault, and there were no injuries.</br>During the electrical transient, the voltage depression tripped the Unit 1 "A" Reactor Protection System (RPS) bus which caused a 1/2 scram and certain protective logic systems to de-energize by design. The following invalid actuations occurred as a result of the loss of power to the RPS bus: partial Group 11 Isolation (Primary Containment); Group III Isolation (Reactor Water Cleanup); Reactor Building Ventilation Isolation; Control Room Ventilation Isolation; and Standby Gas Treatment Initiation.</br>The electrical transient also tripped the Unit 1 ECCS keep�fill pump, resulting in the Core Spray (CS) discharge pressure decreasing to the alarm setpoint. Both CS subsystems were conservatively declared inoperable and entry into Technical Specifications (TS) 3.0.3 occurred at 1936 hours. Subsequent fill and vent activities confirmed no air existed in the discharge headers of the CS subsystems (no loss of safety function) and both subsystems were declared operable with TS 3.0.3 being exited at 2017 hours. Following the electrical transient, the Unit 1 generator was temporarily limited to approximately 90% load due to elevated vibration on Turbine Bearing No. 10. In-plant walk-downs identified no other equipment concerns. Unit 1 returned to full power on April 2, 2012, following confirmation the bearing vibration is acceptable for long-term operation. Unit 2 was in a scheduled refueling outage during the event and was unaffected by the electrical transient. A Root Cause Investigation is ongoing.</br>The licensee notified the NRC Resident Inspector. }}ee notified the NRC Resident Inspector. }}
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>.
100 +
00:00:00, 30 April 2012 +
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>.
22:25:24, 24 September 2017 +
13:38:00, 30 April 2012 +
true +
false +
36.543 d (877.03 hours, 5.22 weeks, 1.201 months) +
00:36:00, 25 March 2012 +
URL"URL" is a <a href="/Special:Types/URL" title="Special:Types/URL">type</a> and predefined property provided by <a rel="nofollow" class="external text" href="https://www.semantic-mediawiki.org/wiki/Help:Special_properties">Semantic MediaWiki</a> to represent URI/URL values.