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At 2337 of 06/30/2006, it was determined t … At 2337 of 06/30/2006, it was determined that 3 out of 4 Residual Heat Removal Service Water (RHRSW) pumps were inoperable due to a common cause. Each of the 3 affected RHRSW pumps contained motor cooling coils that had experienced flow induced erosion which had significantly reduced the wall thickness of the cooling coil material. In some cases, the thinning was sufficient to cause through wall leakage of water into the upper motor bearing oil reservoir and subsequently displace oil out of the reservoir. Currently, 2 of the 3 affected RHRSW pumps have been removed from service for repairs. 1 of those pumps is expected to be returned to service shortly. The 3rd affected pump remains available for use, but has been conservatively declared inoperable based on Engineering evaluation that indicates a common cause failure mechanism likely exists, based on common fabrication methods used for all RHRSW pump motor cooling coils. The 4th (unaffected) RHRSW pump remains Operable because its cooling coil was replaced approximately 1 month ago. Under these conditions, sufficient confidence that the affected RHRSW pumps could perform their post LOCA mission does not exist. With only 1 of the 4 RHRSW pumps remaining Operable, the RHRSW System is not capable of performing its safety function. This event is reportable under 10CFR50.72(b)(3)(v)(B) and 50.73(a)(2)(v)(B).</br>With 3 out of the 4 RHRSW pumps considered inoperable, the licensee is currently in an 8 hour Tech Spec LCO action statement. However, with expected the return of one of these pumps to operable status within the next hour, the LCO will convert to a 7 day action statement.</br>The licensee notified the NRC Resident Inspector.ensee notified the NRC Resident Inspector. +
04:37:00, 1 July 2006 +
42,680 +
01:39:00, 1 July 2006 +
04:37:00, 1 July 2006 +
At 2337 of 06/30/2006, it was determined t … At 2337 of 06/30/2006, it was determined that 3 out of 4 Residual Heat Removal Service Water (RHRSW) pumps were inoperable due to a common cause. Each of the 3 affected RHRSW pumps contained motor cooling coils that had experienced flow induced erosion which had significantly reduced the wall thickness of the cooling coil material. In some cases, the thinning was sufficient to cause through wall leakage of water into the upper motor bearing oil reservoir and subsequently displace oil out of the reservoir. Currently, 2 of the 3 affected RHRSW pumps have been removed from service for repairs. 1 of those pumps is expected to be returned to service shortly. The 3rd affected pump remains available for use, but has been conservatively declared inoperable based on Engineering evaluation that indicates a common cause failure mechanism likely exists, based on common fabrication methods used for all RHRSW pump motor cooling coils. The 4th (unaffected) RHRSW pump remains Operable because its cooling coil was replaced approximately 1 month ago. Under these conditions, sufficient confidence that the affected RHRSW pumps could perform their post LOCA mission does not exist. With only 1 of the 4 RHRSW pumps remaining Operable, the RHRSW System is not capable of performing its safety function. This event is reportable under 10CFR50.72(b)(3)(v)(B) and 50.73(a)(2)(v)(B).</br>With 3 out of the 4 RHRSW pumps considered inoperable, the licensee is currently in an 8 hour Tech Spec LCO action statement. However, with expected the return of one of these pumps to operable status within the next hour, the LCO will convert to a 7 day action statement.</br>The licensee notified the NRC Resident Inspector.ensee notified the NRC Resident Inspector. +
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96 +
00:00:00, 1 July 2006 +
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>.
02:18:28, 2 March 2018 +
01:39:00, 1 July 2006 +
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-0.124 d (-2.97 hours, -0.0177 weeks, -0.00407 months) +
04:37:00, 1 July 2006 +
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.