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A preliminary finding of substantial safet … A preliminary finding of substantial safety significance (Yellow) and an associated apparent violation of Title 10 of the Code of Federal Regulations (10 CFR) Part 50, Appendix B, Criterion V, Instructions, Procedures, and Drawings, was self-revealed on September 25, 2011. The licensee failed to ensure that the work instructions on safety-related 125-Volt direct current (DC) Distribution Panel D11-2 through Work Orders (WO) 291194-01, 291210-01, and 291123-03, all activities that affected quality, were adequate for the scheduled work; and the licensee failed to ensure the work instructions were followed by your staff for the affected activity. As a result of these deficiencies, during the work in the field on the energized Panel D11-2, a positive horizontal bus bar rotated and contacted a negative horizontal bus bar. This in turn, caused an electrical fault in Panel D11-2 and a complete loss of the left train 125-Volt DC safety-related system coincident with both 120-Volt preferred alternating current (AC) power sources, busses Y-10 and Y-30. These electrical losses resulted in a reactor and turbine trip at approximately 3:06 p.m. on September 25, 2011, coincident with a Safety Injection Actuation Signal, Main Steam Isolation Signal, Containment High Radiation Signal, Containment Isolation Signal, Auxiliary Feedwater Actuation Signal, and Containment High Pressure Alarm (no actuation signal). This issue was documented in the licensees corrective action program as CR-PLP-2011-04822 and at the end of this inspection, the licensee continued to perform a root cause evaluation to determine the causes of the event and develop corrective actions. As a remedial corrective action on September 25, 2011, the licensee repaired the damage caused to Panel D11-2 to restore it to service and addressed the operability and effect of the transient on other components. The inspectors determined that the finding was more than minor in accordance with Inspection Manual Chapter (IMC) 0612, Power Reactor Inspection Reports, Appendix B, Issue Screening, dated December 24, 2009, because it was associated with the Procedure Quality and Human Performance attributes of the Initiating Events The inspectors determined that the finding was more than minor in accordance with Inspection Manual Chapter (IMC) 0612, Power Reactor Inspection Reports, Appendix B, Issue Screening, dated December 24, 2009, because it was associated with the Procedure Quality and Human Performance attributes of the Initiating Eventsrmance attributes of the Initiating Events

Discovered date

23:59:59, 31 December 2011 +

Docket

05000255 +

Equipment trip

Turbine Trip +

Event date

23:59:59, 31 December 2011 +

Finding integer

2 +

Finding type

Finding +

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>.

INPO aspect

QA.4 +

Identified by

NRC identified +

Inspection Manual Chapter

NRC Inspection Manual 0612, Power Reactor Inspection Reports +

Inspection procedure

IP 93812 +

Inspection report

IR 05000255/2011014 +

Inspector

A Scarbeary +, Alan Dahbur +, Jack Giessner + and Robert Krsek +

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>.

12:56:44, 25 September 2017 +

Person

A Scarbeary +, Alan Dahbur +, Jack Giessner + and Robert Krsek +

2011Q4 +

Yellow +

23:59:59, 31 December 2011 +

System