Browse wiki
Jump to navigation
Jump to search
10 CFR 50.72(b)(3)(v)(A), Loss of Safety Function - Shutdown the Reactor +, 10 CFR 50.72(b)(3)(v)(B), Loss of Safety Function - Remove Residual Heat +, 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident +, 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition +, 10 CFR 50.72#b3iiB + and 10 CFR 50.72#b3vA +
The following information was obtained fro … The following information was obtained from the licensee via facsimile (licensee text in quotes):</br>On April 5, 2005 at 1600 (hrs. CDT), Monticello Nuclear Generating Plant during a review of the Alternate Shutdown System (ASDS) as part of the corrective actions for LER 2005-01, submitted on April 4, 2005 (Event Notification #41436) discovered a second breaker affected by a similar cause as identified in the LER. The Bus 16 source (Breaker 152-609) to Load Center #104 has a similar potential vulnerability with the ASDS isolation design that could result in Load Center #104 being locked out in the event of a Control Room or Cable Spreading Room fire. The Monticello Appendix R Safe Shutdown Analysis for Control Room/Cable Spreading (Room) fire assumes a loss of control of Division I and II equipment from the Control room, however safe shutdown is achieved remotely from the ASDS panel. ASDS design is such that a Control Room/Cable Spreading Room fire would not impede the ability to safely shutdown and maintain the plant in a shutdown condition.</br>Contrary to the ASDS design, it was discovered that an unisolated metering circuit could result in Load Center #104 being locked out in the event of a Control Room/Cable Spreading Room fire. The bus lockout is not isolated by the ASDS transfer switches, therefore, this condition could result in failure of Load Center #104 to re-energize during the implementation of the Shutdown Outside Control Room procedure. ASDS is not required to be operable at this time. </br>As a result of this determination, MNGP will issue a revision to LER 2005-01 to the NRC to reflect the new information.</br>This event is being reported as a potential loss of safety function (10CFR50.72(b)(3)(v)(A,B, and D) and as a degraded or unanalyzed condition (10CFR50.72(b)(3)(ii)(B). The NRC (Resident Inspector) has been notified.RC (Resident Inspector) has been notified. +
22:00:00, 5 April 2005 +
41,567 +
22:26:00, 5 April 2005 +
22:00:00, 5 April 2005 +
The following information was obtained fro … The following information was obtained from the licensee via facsimile (licensee text in quotes):</br>On April 5, 2005 at 1600 (hrs. CDT), Monticello Nuclear Generating Plant during a review of the Alternate Shutdown System (ASDS) as part of the corrective actions for LER 2005-01, submitted on April 4, 2005 (Event Notification #41436) discovered a second breaker affected by a similar cause as identified in the LER. The Bus 16 source (Breaker 152-609) to Load Center #104 has a similar potential vulnerability with the ASDS isolation design that could result in Load Center #104 being locked out in the event of a Control Room or Cable Spreading Room fire. The Monticello Appendix R Safe Shutdown Analysis for Control Room/Cable Spreading (Room) fire assumes a loss of control of Division I and II equipment from the Control room, however safe shutdown is achieved remotely from the ASDS panel. ASDS design is such that a Control Room/Cable Spreading Room fire would not impede the ability to safely shutdown and maintain the plant in a shutdown condition.</br>Contrary to the ASDS design, it was discovered that an unisolated metering circuit could result in Load Center #104 being locked out in the event of a Control Room/Cable Spreading Room fire. The bus lockout is not isolated by the ASDS transfer switches, therefore, this condition could result in failure of Load Center #104 to re-energize during the implementation of the Shutdown Outside Control Room procedure. ASDS is not required to be operable at this time. </br>As a result of this determination, MNGP will issue a revision to LER 2005-01 to the NRC to reflect the new information.</br>This event is being reported as a potential loss of safety function (10CFR50.72(b)(3)(v)(A,B, and D) and as a degraded or unanalyzed condition (10CFR50.72(b)(3)(ii)(B). The NRC (Resident Inspector) has been notified.RC (Resident Inspector) has been notified. +
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, 5 April 2005 +
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>.
02:21:21, 2 March 2018 +
22:26:00, 5 April 2005 +
false +
false +
10 CFR 50.72(b)(3)(v)(A), Loss of Safety Function - Shutdown the Reactor +, 10 CFR 50.72(b)(3)(v)(B), Loss of Safety Function - Remove Residual Heat +, 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident + and 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition +
0.0179 d (0.43 hours, 0.00256 weeks, 5.89014e-4 months) +
22:00:00, 5 April 2005 +
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.