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This report is being made under 10CFR50.72 … This report is being made under 10CFR50.72(b)(3)(iv)(A), 'Any event or condition that results in valid actuation of any of the systems listed in paragraph (b)(3)(iv)(B) of this section' due to an auto start of 'A' and 'B' Standby Diesel Generators. At 1913 CDT, a grid disturbance during a local thunderstorm caused a valid bus undervoltage condition that resulted in the auto start of both the 'A' and 'B' Standby Diesel Generators. The 'A' and 'B' Standby Diesel Generator supply breakers did not close onto their respective buses as they remained powered by their normal power supply, the 1X003 Startup Transformer, during and after the event. NextEra Duane Arnold personnel inspections revealed no issues with breakers in the switchyard. ITC (Iowa Transmission Company) reported a fault on a 161 Kv line in the NextEra Duane Arnold vicinity. Offsite power remained operable during and following the event.</br>As designed the 'A' and 'B' Emergency Service Water systems auto started when the diesel generators auto started. The Emergency Service Water systems and both Standby Diesel Generators have been returned to standby/readiness condition. All ECCS (Emergency Core Cooling System) systems were available before the event and have remained available following the event.</br>The licensee notified the NRC Resident Inspector.ensee notified the NRC Resident Inspector. +
00:13:00, 1 July 2014 +
50,246 +
23:54:00, 30 June 2014 +
00:13:00, 1 July 2014 +
This report is being made under 10CFR50.72 … This report is being made under 10CFR50.72(b)(3)(iv)(A), 'Any event or condition that results in valid actuation of any of the systems listed in paragraph (b)(3)(iv)(B) of this section' due to an auto start of 'A' and 'B' Standby Diesel Generators. At 1913 CDT, a grid disturbance during a local thunderstorm caused a valid bus undervoltage condition that resulted in the auto start of both the 'A' and 'B' Standby Diesel Generators. The 'A' and 'B' Standby Diesel Generator supply breakers did not close onto their respective buses as they remained powered by their normal power supply, the 1X003 Startup Transformer, during and after the event. NextEra Duane Arnold personnel inspections revealed no issues with breakers in the switchyard. ITC (Iowa Transmission Company) reported a fault on a 161 Kv line in the NextEra Duane Arnold vicinity. Offsite power remained operable during and following the event.</br>As designed the 'A' and 'B' Emergency Service Water systems auto started when the diesel generators auto started. The Emergency Service Water systems and both Standby Diesel Generators have been returned to standby/readiness condition. All ECCS (Emergency Core Cooling System) systems were available before the event and have remained available following the event.</br>The licensee notified the NRC Resident Inspector.ensee notified the NRC Resident Inspector. +
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98 +
00:00:00, 1 July 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>.
01:50:20, 2 March 2018 +
23:54:00, 30 June 2014 +
true +
false +
-0.0133 d (-0.32 hours, -0.0019 weeks, -4.38336e-4 months) +
00:13:00, 1 July 2014 +
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