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Immediate notifications are being made for … Immediate notifications are being made for the following events:</br>1) Valid RPS non-critical actuation: 8 hour notification per 50.72(b)(3)(iv)(B)</br>2) Group 1, 2, 3, 4 and 5 isolations: 8 hour notification per 50.72(b)(3)(iv)(B)</br>3) Loss of decay heat removal (RHR Shutdown Cooling) isolated: 8 hour notification per 50.72(b)(3)(v)(A)</br>4) Auto start of 'A' Standby Diesel Generator and subsequent pick up of essential buses by both 'A' and 'B' Standby Diesel Generators: 8 hour notification per 50.72(b)(3)(iv)(A).</br>Just prior to the event the plant was in Mode 5 with core alterations in progress and the 'B' Standby Diesel Generator being run manually for post maintenance testing. At 1756 hours on 2/24/2007, core alterations were halted due to indications that the grid was becoming unstable. Freezing rain had been in progress all day. At 1757 hours an electrical transient occurred as some of the offsite lines coming into the switchyard were lost. The 'B' Reactor Protection System (RPS) bus was lost. A full RPS trip occurred from loss of the 'B' RPS bus and too few inputs to the 'A' RPS trip logic. The loss of 'B' RPS power resulted in Groups 1, 2, 3, 4 and 5 isolations. The Group 4 isolation caused a loss of decay heat removal capability (RHR Shutdown Cooling isolated). The 'A' Standby Diesel Generator auto started, but the 1A3 essential bus remained powered from offsite sources. The 'B' SBDG was already running. The 1A4 bus also remained powered from offsite sources. At 1820 hours, a degraded voltage trip signal was received resulting in both emergency diesel generators picking up their respective buses.</br>At present, the essential buses 1A3 and 1A4 are being carried by the emergency diesel generators. Only one of the six lines supplying offsite power to the site is available. Both non-essential buses are being powered from the one offsite line. The emergency buses will remain on the emergency diesel generators until additional offsite lines can be restored. RHR Shutdown Cooling was restored at 1826 hours.</br>The licensee notified the NRC Resident Inspector, State and local officials.dent Inspector, State and local officials.
23:56:00, 24 February 2007 +
43,185 +
23:03:00, 24 February 2007 +
23:56:00, 24 February 2007 +
Immediate notifications are being made for … Immediate notifications are being made for the following events:</br>1) Valid RPS non-critical actuation: 8 hour notification per 50.72(b)(3)(iv)(B)</br>2) Group 1, 2, 3, 4 and 5 isolations: 8 hour notification per 50.72(b)(3)(iv)(B)</br>3) Loss of decay heat removal (RHR Shutdown Cooling) isolated: 8 hour notification per 50.72(b)(3)(v)(A)</br>4) Auto start of 'A' Standby Diesel Generator and subsequent pick up of essential buses by both 'A' and 'B' Standby Diesel Generators: 8 hour notification per 50.72(b)(3)(iv)(A).</br>Just prior to the event the plant was in Mode 5 with core alterations in progress and the 'B' Standby Diesel Generator being run manually for post maintenance testing. At 1756 hours on 2/24/2007, core alterations were halted due to indications that the grid was becoming unstable. Freezing rain had been in progress all day. At 1757 hours an electrical transient occurred as some of the offsite lines coming into the switchyard were lost. The 'B' Reactor Protection System (RPS) bus was lost. A full RPS trip occurred from loss of the 'B' RPS bus and too few inputs to the 'A' RPS trip logic. The loss of 'B' RPS power resulted in Groups 1, 2, 3, 4 and 5 isolations. The Group 4 isolation caused a loss of decay heat removal capability (RHR Shutdown Cooling isolated). The 'A' Standby Diesel Generator auto started, but the 1A3 essential bus remained powered from offsite sources. The 'B' SBDG was already running. The 1A4 bus also remained powered from offsite sources. At 1820 hours, a degraded voltage trip signal was received resulting in both emergency diesel generators picking up their respective buses.</br>At present, the essential buses 1A3 and 1A4 are being carried by the emergency diesel generators. Only one of the six lines supplying offsite power to the site is available. Both non-essential buses are being powered from the one offsite line. The emergency buses will remain on the emergency diesel generators until additional offsite lines can be restored. RHR Shutdown Cooling was restored at 1826 hours.</br>The licensee notified the NRC Resident Inspector, State and local officials.dent Inspector, State and local officials.
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00:00:00, 24 February 2007 +
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>.
02:17:11, 2 March 2018 +
23:03:00, 24 February 2007 +
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23:56:00, 24 February 2007 +
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