Browse wiki
Jump to navigation
Jump to search
On September 12, North Anna Power Station … On September 12, North Anna Power Station Unit 1 entered a scheduled refueling outage. During the outage while performing reviews for a design change, it was determined that some uncontrolled plant drawings indicated that Microtherm insulation may have been installed on some piping locations inside the containment. The Microtherm insulation impacts the new containment sump strainers installed to address NRC GSI-191 requirements. It was subsequently confirmed via walk downs that the Unit 1 containment contained some Microtherm insulation.</br>Based on conflicting information on the possible installation of Microtherm inside Unit 2 containment and the identification of Microtherm insulation on Unit 1, a conservative decision was made to shutdown Unit 2 on September 29, and the Unit was cooled down to Mode 5 to allow a detailed inspection to be performed. The areas where the Microtherm insulation was potentially installed could not be inspected with the Unit at power.</br>Subsequent inspections have confirmed that the Microtherm insulation was installed in some areas of the Unit 2 containment. These locations include the reactor vessel nozzles and reactor coolant pump casings. Plans are being developed to remove this insulation on both units.</br>The overall impact of the Microtherm insulation on the containment sump operation is being evaluated by engineering.</br>The licensee has notified the NRC Resident Inspector and the Louisa County Administrator.ector and the Louisa County Administrator. +
18:15:00, 29 September 2010 +
46,294 +
15:36:00, 30 September 2010 +
18:15:00, 29 September 2010 +
On September 12, North Anna Power Station … On September 12, North Anna Power Station Unit 1 entered a scheduled refueling outage. During the outage while performing reviews for a design change, it was determined that some uncontrolled plant drawings indicated that Microtherm insulation may have been installed on some piping locations inside the containment. The Microtherm insulation impacts the new containment sump strainers installed to address NRC GSI-191 requirements. It was subsequently confirmed via walk downs that the Unit 1 containment contained some Microtherm insulation.</br>Based on conflicting information on the possible installation of Microtherm inside Unit 2 containment and the identification of Microtherm insulation on Unit 1, a conservative decision was made to shutdown Unit 2 on September 29, and the Unit was cooled down to Mode 5 to allow a detailed inspection to be performed. The areas where the Microtherm insulation was potentially installed could not be inspected with the Unit at power.</br>Subsequent inspections have confirmed that the Microtherm insulation was installed in some areas of the Unit 2 containment. These locations include the reactor vessel nozzles and reactor coolant pump casings. Plans are being developed to remove this insulation on both units.</br>The overall impact of the Microtherm insulation on the containment sump operation is being evaluated by engineering.</br>The licensee has notified the NRC Resident Inspector and the Louisa County Administrator.ector and the Louisa County Administrator. +
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, 30 September 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>.
02:08:45, 2 March 2018 +
15:36:00, 30 September 2010 +
false +
false +
0.89 d (21.35 hours, 0.127 weeks, 0.0292 months) +
18:15:00, 29 September 2010 +
Discovery of Microtherm Insulation in Containment Which Could Impact Sump Strainer Performance +
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.