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On August 8, 2012, Unit 2 tripped followin … On August 8, 2012, Unit 2 tripped following a loss of condenser vacuum. Following the trip, main feedwater regulating valve A failed to close and remained approximately 8 percent open, complicating the operator response to the event. The licensee concluded that the valve jacking mechanism had been left in the wrong position following maintenance. An NRC finding associated with this event is documented in NRC inspection report 05000313/2012005; 0500368/2012005 as FIN 05000368/2012005-008 (ADAMS Accession No. ML13045A520). Following the Unit 2 reactor trip on March 31, 2013, operators identified that main feedwater regulating valve A failed to indicate closed. This indication caused the operators to trip main feedwater pump A and manually initiate the emergency feedwater actuation system. Arkansas Nuclear One Unit 2 is a Combustion Engineering designed plant and emergency feedwater is not normally actuated on a non-complicated reactor trip. Operators subsequently placed the auxiliary feedwater system in service, which required operators to manually inhibit the emergency feedwater system, rendering both trains inoperable and requiring entry into Technical Specification 3.0.3 for a short period of time. This again complicated operator response to the trip. The licensee later determined that the regulating valve actually had closed, and the valve indication was in error. The condition was corrected by tightening loose adjustment screws on the valve position indication limit switches. The team concluded that additional inspection was required to assess the effectiveness of the licensee maintenance practices on the main feedwater regulating valves: Unresolved Item URI 05000368/2013011-04, Main Feedwater Regulating Valve Maintenance Practices.er Regulating Valve Maintenance Practices. +

Discovered date

23:59:59, 30 June 2013 +

Docket

05000313 + and 05000368 +

Document

IR 05000313/2012005 +

Equipment trip

Reactor Trip +

Event date

23:59:59, 30 June 2013 +

Finding

05000368/FIN-2012005-008 + and 05000368/FIN-2013011-04 +

Finding integer

4 +

Finding type

URI +

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IR 05000313/2012005 + and IR 05000313/2013011 +

Inspector

Geoffrey Miller +, J Watkins +, Lattag Werner +, L Willoughby +, D Allen +, Alfred Sanchez +, David Loveless +, Jim Melfi +, S Jonesb + and Nnaerika Okonkwo +

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>.

00:50:16, 21 February 2018 +

Person