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This 60-day telephone notification is bein … This 60-day telephone notification is being made per the reporting requirements specified by 10 CFR 50.73(a)(2)(iv)(A) and 10 CFR 50.73(a)(1) to describe an invalid actuation of a general containment isolation signal affecting more than one system.</br>On January 21, 2014, at 0746 hours Central Standard Time (CST), during performance of the 3C Emergency Diesel Generator (EDG) post modification test instructions, the EDG was supplying a shutdown board in isochronous mode when the 3B Residual Heat Removal (RHR) pump was started causing the voltage to drop to 2100 volts. At this time, Browns Ferry Nuclear Plant (BFN) Unit 3, received a half scram and Primary Containment Isolation System (PCIS) groups 2, 3, 6, and 8 isolation signals as a result of losing the 3B Reactor Protection System (RPS) Motor Generator (MG) set due to a time delay relay failure on under voltage. The PCIS groups 2, 3, 6, and 8 isolations caused the initiation of all three trains of the Standby Gas Treatment (SBGT) system, Control Room Emergency Ventilation (CREV) subsystem 'A', and the Refuel fans tripped and isolated. Operations personnel responded to the PCIS initiation, ensured all equipment operated as designed, and placed affected systems back in service.</br>Plant conditions which initiate PCIS group 2 actuations are Reactor Vessel Low Water Level (Level 3) or High Drywell Pressure. The PCIS group 3 actuations are initiated by Reactor Vessel Low Water Level (Level 3) or Reactor Water Cleanup Area High Temperature. The PCIS group 6 actuations are initiated by Reactor Vessel Low Water Level (Level 3), High Drywell Pressure, or Reactor Building Ventilation Exhaust High Radiation (Reactor Zone or Refuel Zone). The PCIS group 8 actuations are initiated by Low Reactor Vessel Water Level (Level 3) or High Drywell Pressure. At the time of the event, these conditions did not exist; therefore, the actuation of the PCIS was invalid.</br>The apparent cause for this condition was a failure of a 3B RPS MG set time delay relay due to lack of a preventive maintenance strategy. The vendor manual for the time delay relay did not specify a qualified life. The replacement relay specified a replacement schedule of 10 years. The relay that failed was installed for approximately 13 years. To address this condition, preventive maintenance is being developed for MG set time delay relays. In addition, the only remaining relay, similar to the failed relay, is scheduled be replaced on August 25, 2014, for the 2A RPS MG set.</br>The licensee has notified the NRC Resident Inspector.e has notified the NRC Resident Inspector.
13:46:00, 21 January 2014 +
49,942 +
14:10:00, 21 March 2014 +
13:46:00, 21 January 2014 +
This 60-day telephone notification is bein … This 60-day telephone notification is being made per the reporting requirements specified by 10 CFR 50.73(a)(2)(iv)(A) and 10 CFR 50.73(a)(1) to describe an invalid actuation of a general containment isolation signal affecting more than one system.</br>On January 21, 2014, at 0746 hours Central Standard Time (CST), during performance of the 3C Emergency Diesel Generator (EDG) post modification test instructions, the EDG was supplying a shutdown board in isochronous mode when the 3B Residual Heat Removal (RHR) pump was started causing the voltage to drop to 2100 volts. At this time, Browns Ferry Nuclear Plant (BFN) Unit 3, received a half scram and Primary Containment Isolation System (PCIS) groups 2, 3, 6, and 8 isolation signals as a result of losing the 3B Reactor Protection System (RPS) Motor Generator (MG) set due to a time delay relay failure on under voltage. The PCIS groups 2, 3, 6, and 8 isolations caused the initiation of all three trains of the Standby Gas Treatment (SBGT) system, Control Room Emergency Ventilation (CREV) subsystem 'A', and the Refuel fans tripped and isolated. Operations personnel responded to the PCIS initiation, ensured all equipment operated as designed, and placed affected systems back in service.</br>Plant conditions which initiate PCIS group 2 actuations are Reactor Vessel Low Water Level (Level 3) or High Drywell Pressure. The PCIS group 3 actuations are initiated by Reactor Vessel Low Water Level (Level 3) or Reactor Water Cleanup Area High Temperature. The PCIS group 6 actuations are initiated by Reactor Vessel Low Water Level (Level 3), High Drywell Pressure, or Reactor Building Ventilation Exhaust High Radiation (Reactor Zone or Refuel Zone). The PCIS group 8 actuations are initiated by Low Reactor Vessel Water Level (Level 3) or High Drywell Pressure. At the time of the event, these conditions did not exist; therefore, the actuation of the PCIS was invalid.</br>The apparent cause for this condition was a failure of a 3B RPS MG set time delay relay due to lack of a preventive maintenance strategy. The vendor manual for the time delay relay did not specify a qualified life. The replacement relay specified a replacement schedule of 10 years. The relay that failed was installed for approximately 13 years. To address this condition, preventive maintenance is being developed for MG set time delay relays. In addition, the only remaining relay, similar to the failed relay, is scheduled be replaced on August 25, 2014, for the 2A RPS MG set.</br>The licensee has notified the NRC Resident Inspector.e has notified the NRC Resident Inspector.
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100 +
00:00:00, 21 March 2014 +
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>.
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14:10:00, 21 March 2014 +
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59.058 d (1,417.4 hours, 8.437 weeks, 1.942 months) +
13:46:00, 21 January 2014 +
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.