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On November 3, 2010 at 1021 CDT, operators … On November 3, 2010 at 1021 CDT, operators attempted to start the Unit 2 startup feedpump to support a two hour maintenance run. The feeder breaker for the startup feedpump exploded causing an undervoltage condition on Auxiliary Bus 1H and Standby Bus 1H which resulted in an automatic reactor trip due to reactor coolant pump undervoltage. All control rods inserted into the core. At 1038 CDT, the site declared an UNUSUAL EVENT (HU-2) due to an explosion in the protected area which affects normal plant operations. The standby diesel generator (EDG-23) started and loaded to the 'C' train loads which sequenced properly. The auxiliary feedwater system automatically started as expected providing feedwater to the steam generators. The normal feedwater pumps were secured. Decay heat is being removed from Unit 2 using the normal steam dump valves to the main condenser. There is no primary to secondary leakage. The plant is stable and in MODE 3 with no challenges to reactor safety. There was no impact on Unit 1.</br>At 1240 CDT the licensee terminated the UNUSUAL EVENT.</br>The licensee is investigating the cause of the breaker explosion and if the other standby diesel generator (EDG-21) should have started due to the undervoltage condition.</br>The licensee notified the NRC Resident Inspector.</br>* * * UPDATE FROM TAPLETT TO KLCO ON 11/3/10 AT 1530 EDT * * * </br>A News Release is being planned so this condition is also being reported pursuant to 10 CFR 50.72(b)(2)(xi).</br>During the electrical fault condition, some Train A components stopped running although no Train A low voltage ESF actuation occurred, The reason for this occurrence is not fully understood,</br>The breaker malfunction did not result in a fire.</br>The licensee will notify the NRC Resident Inspector.</br>Notified: R4DO (Spitzberg); NRR (Thorp); R4RA (Collins); NRR (Boger); IRD (Gott) DHS (Hill); FEMA (Hollis)</br>* * * UPDATE FROM HARRISON TO SNYDER ON 11/4/10 AT 1920 EDT * * * </br>The licensee called to correct an editorial error in the original report above. The second sentence of the original report above should refer to Auxiliary Bus 2H and Standby Bus 2H since this is a Unit 2 issue.</br>Notified: R4DO (Spitzberg). Unit 2 issue.
Notified: R4DO (Spitzberg).
15:21:00, 3 November 2010 +
46,387 +
12:09:00, 3 November 2010 +
15:21:00, 3 November 2010 +
On November 3, 2010 at 1021 CDT, operators … On November 3, 2010 at 1021 CDT, operators attempted to start the Unit 2 startup feedpump to support a two hour maintenance run. The feeder breaker for the startup feedpump exploded causing an undervoltage condition on Auxiliary Bus 1H and Standby Bus 1H which resulted in an automatic reactor trip due to reactor coolant pump undervoltage. All control rods inserted into the core. At 1038 CDT, the site declared an UNUSUAL EVENT (HU-2) due to an explosion in the protected area which affects normal plant operations. The standby diesel generator (EDG-23) started and loaded to the 'C' train loads which sequenced properly. The auxiliary feedwater system automatically started as expected providing feedwater to the steam generators. The normal feedwater pumps were secured. Decay heat is being removed from Unit 2 using the normal steam dump valves to the main condenser. There is no primary to secondary leakage. The plant is stable and in MODE 3 with no challenges to reactor safety. There was no impact on Unit 1.</br>At 1240 CDT the licensee terminated the UNUSUAL EVENT.</br>The licensee is investigating the cause of the breaker explosion and if the other standby diesel generator (EDG-21) should have started due to the undervoltage condition.</br>The licensee notified the NRC Resident Inspector.</br>* * * UPDATE FROM TAPLETT TO KLCO ON 11/3/10 AT 1530 EDT * * * </br>A News Release is being planned so this condition is also being reported pursuant to 10 CFR 50.72(b)(2)(xi).</br>During the electrical fault condition, some Train A components stopped running although no Train A low voltage ESF actuation occurred, The reason for this occurrence is not fully understood,</br>The breaker malfunction did not result in a fire.</br>The licensee will notify the NRC Resident Inspector.</br>Notified: R4DO (Spitzberg); NRR (Thorp); R4RA (Collins); NRR (Boger); IRD (Gott) DHS (Hill); FEMA (Hollis)</br>* * * UPDATE FROM HARRISON TO SNYDER ON 11/4/10 AT 1920 EDT * * * </br>The licensee called to correct an editorial error in the original report above. The second sentence of the original report above should refer to Auxiliary Bus 2H and Standby Bus 2H since this is a Unit 2 issue.</br>Notified: R4DO (Spitzberg). Unit 2 issue.
Notified: R4DO (Spitzberg).
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100 +
05000499/LER-2010-005, Regarding Startup Feed Pump 24 Breaker Failure and Unit 2 Reactor Trip +, 05000499/LER-2010-005-02, Regarding Startup Feed Pump 24 Breaker Failure and Unit 2 Reactor Trip +, 05000499/LER-2010-005-01, For South Texas Project Unit 2, Regarding Startup Feed Pump 24 Breaker Failure and Unit 2 Reactor Trip +, Regarding Startup Feed Pump 24 Breaker Failure and Unit 2 Reactor Trip + and For South Texas Project Unit 2 +
00:00:00, 4 November 2010 +
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>.
02:08:30, 2 March 2018 +
12:09:00, 3 November 2010 +
true +
-0.133 d (-3.2 hours, -0.019 weeks, -0.00438 months) +
15:21:00, 3 November 2010 +
Unusual Event Declared Due to an Explosion in the Protected Area Which Affects Normal Operations +
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