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On September 17, 2015, at 1222 hours, with … On September 17, 2015, at 1222 hours, with Unit 2 in Mode 5 at the beginning of a refueling outage, an electrical fault on the 2A 6.9 kV bus resulted in the loss of the 2A startup transformer and its associated non-safety related 2A2 and safety related 2A3 busses. At the time of the event, the 2A Emergency Diesel Generator (EDG) had been properly removed from service for scheduled maintenance. The loss of the 2A start up transformer initiated the under voltage relays, which resulted in a valid actuation signal that would have started the 2A EDG.</br>Additionally, the 2A train of shutdown cooling (SDC) was de-energized; the 2B (protected) train of SDC was not affected by the event and remained in service to remove decay heat. The 2A shutdown cooling train was restored and made available on September 19, 2015 at 0030. The 2B EDG and 2B startup transformer remained operable.</br>St. Lucie did not report this event within 8 hours of occurrence, however, this event was subsequently determined to be reportable pursuant to 10CFR50.72(b )(3)(iv)(A).</br>During this event, Unit 1 experienced a loss of the 1A startup transformer. There was no effect on Unit 1 operation, as its associated non-safety and safety-related busses remained powered by the auxiliary transformer. The 1A startup transformer returned to service on September 18, 2015 at 2103.</br>The licensee informed the NRC Resident Inspector.ensee informed the NRC Resident Inspector. +
16:22:00, 17 September 2015 +
51,423 +
16:34:00, 24 September 2015 +
16:22:00, 17 September 2015 +
On September 17, 2015, at 1222 hours, with … On September 17, 2015, at 1222 hours, with Unit 2 in Mode 5 at the beginning of a refueling outage, an electrical fault on the 2A 6.9 kV bus resulted in the loss of the 2A startup transformer and its associated non-safety related 2A2 and safety related 2A3 busses. At the time of the event, the 2A Emergency Diesel Generator (EDG) had been properly removed from service for scheduled maintenance. The loss of the 2A start up transformer initiated the under voltage relays, which resulted in a valid actuation signal that would have started the 2A EDG.</br>Additionally, the 2A train of shutdown cooling (SDC) was de-energized; the 2B (protected) train of SDC was not affected by the event and remained in service to remove decay heat. The 2A shutdown cooling train was restored and made available on September 19, 2015 at 0030. The 2B EDG and 2B startup transformer remained operable.</br>St. Lucie did not report this event within 8 hours of occurrence, however, this event was subsequently determined to be reportable pursuant to 10CFR50.72(b )(3)(iv)(A).</br>During this event, Unit 1 experienced a loss of the 1A startup transformer. There was no effect on Unit 1 operation, as its associated non-safety and safety-related busses remained powered by the auxiliary transformer. The 1A startup transformer returned to service on September 18, 2015 at 2103.</br>The licensee informed the NRC Resident Inspector.ensee informed 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>.
00:00:00, 24 September 2015 +
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>.
01:46:41, 2 March 2018 +
16:34:00, 24 September 2015 +
false +
false +
7.008 d (168.2 hours, 1.001 weeks, 0.23 months) +
16:22:00, 17 September 2015 +
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.