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One self-revealed finding of very low safe … One self-revealed finding of very low safety significance was identified for the failure to implement the Unit 2 main generator volts per hertz differential relay modification per design, as required by Engineering Change (EC) 50316, Unit 2 Replacement of the Volts/Hertz Relay and the Overall Differential Relays with a Multifunctional Relay Unit. Consequently, while ascending in power, the relay actuated causing a main generator trip, resultant turbine trip and subsequent reactor trip on April 30, 2012. For corrective actions, the licensee programmed the correct preset settings into the volts per hertz differential relay prior to restarting Unit 2 and plans to add additional procedural requirements to ensure modification requirements are properly incorporated into the associated work orders. This issue was entered into the licensees corrective action program (CAP) as Action Request (AR) 2012-5744. The inspectors concluded the finding was more than minor because it is associated with the Initiating Events Cornerstone attribute of Procedure Quality. In addition, it adversely affected the Cornerstone objective to limit the likelihood of events that upset plant stability. Specifically, the failure to implement the SEL-487E relay modification per design, contributed to a main generator trip and resultant automatic reactor trip. The inspectors used IMC 0609, Significance Determination Process, Attachment 0609.04, Phase 1 - Initial Screening and Characterization of Findings, Table 4a for the Initiating Events Cornerstone to determine the significance. This finding was of very low safety significance because the finding did not contribute to both the likelihood of a reactor trip and the likelihood that mitigation equipment will not be available. This finding is associated with a cross-cutting aspect in the resources component of the human performance cross-cutting area. Specifically, the work order associated with installing the volts per hertz overall differential relay did not include sufficient guidance to ensure the SEL-487E relay modification was installed as designed.ay modification was installed as designed.
23:59:59, 30 June 2012 +
23:59:59, 30 June 2012 +
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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>.
19:04:56, 30 September 2017 +
23:59:59, 30 June 2012 +