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A licensee-identified violation of Hatch U … A licensee-identified violation of Hatch Unit 1 TS 3.8.1, Electrical Power Systems Alternating Current (AC) Sources Operating, was discovered on March 10, 2012 during the performance of surveillance testing for the 1C emergency diesel generator. TS 3.8.1 requires, in part, during Unit 1 Modes, 1, 2, and 3 that two Unit 1 diesel generators are operable. Contrary to TS 3.8.1 Unit 1 operated in Modes 1, 2, and 3 without two operable Unit 1 diesel generators. Specifically, the 1C emergency diesel generator output breaker failed to close as required upon a loss of electrical power to the 1G 4160 volt AC bus. The licensees investigation determined the cause of the breaker closure failure was due to an improper wiring configuration within the 1G 4160 volt AC alternate supply breaker which had existed since March 16, 2010. The inspectors determined per IMC 0612 Appendix B, Issue Screening, dated September 7, 2012, and IMC 0609, Appendix A, The Significance Determination Process For Findings At-Power, dated July 1, 2012, that a detailed risk assessment was required. Regional senior reactor analysts performed the detailed risk assessment which determined the associated risk was less than 1E-6 core damage frequency, and less than 1E-7 large early release frequency. Therefore, this violation screened as Green. The licensee entered this violation into their corrective action program as CR 421971.ir corrective action program as CR 421971. +

Discovered date

23:59:59, 31 December 2012 +

Docket

05000321 + and 05000366 +

Event date

23:59:59, 31 December 2012 +

Finding integer

5 +

Finding type

Non-cited violation +

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Identified by

Licensee-identified +

Inspection Manual Chapter

NRC Inspection Manual 0609/Appendix A, The Significance Determination Process (SDP) for Findings At-Power + and NRC Inspection Manual 0609/Appendix B +

Inspection report

IR 05000321/2012005 +

Inspector

Frank Ehrhardt +, J Laughlin +, M Speck +, E Morris +, D Berkshire +, Wade Loo +, David Hardage +, Mark Schwieg +, Shane Sandal +, Bruno Caballero + and Mark Miller +

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>.

15:46:08, 30 May 2018 +

Person