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A finding of very low safety significance … A finding of very low safety significance with an associated NCV of TS 5.4.1 was self-revealed on January 7, 2012, for the failure to adequately implement a procedure when indications of Primary Coolant System (PCS) leakage exceeding 10 gallons per minute (gpm) were observed by the control room operators. The finding occurred while the plant was shut down and in a cold shutdown condition. Specifically, the licensee discovered that reactor head vent valves MV-PC1060B and MV-PC1060C had not been shut before filling and pressurizing the PCS, contrary to the requirements of procedure SOP-1C, Primary Coolant System-Heatup. The licensee shut the valves and isolated the leak. The leakage resulted in approximately 3000 gallons of primary coolant being transferred to the reactor cavity tilt pit. This leakage was subsequently drained prior to startup. The licensee entered the issue as CR-PLP-2012-00165 in their CAP. The finding was determined to be greater than minor in accordance with IMC 0612 Appendix B, Issue Screening, because it is associated with the Initiating Events Cornerstone attribute of Configuration Control and adversely impacted the objective to limit the likelihood of those events that upset plant stability and challenge critical safety functions during power operations. Specifically, uncontrolled release of coolant from the PCS could challenge plant stability. The issue screened as Green utilizing Attachment 1 of IMC 0609 Appendix G, Shutdown Operations Significance Determination Process. Specifically, the finding and plant conditions at the time did not warrant the use of a Phase 2 or 3 analysis, because there was no impact on any safety functions. The inspectors determined the cause of the finding was associated with the cross-cutting area of human performance. Specifically, by assuming the reactor head vent valves were not open, operations shift personnel did not use conservative assumptions in decision making and adopt a requirement to demonstrate that a proposed action was safe in order to proceed.posed action was safe in order to proceed.

Discovered date

23:59:59, 31 March 2012 +

Docket

05000255 +

Event date

23:59:59, 31 March 2012 +

Finding integer

4 +

Finding type

Non-cited violation +

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INPO aspect

DM.2 +

Identified by

Self-revealing +

Inspection Manual Chapter

NRC Inspection Manual 0609 Appendix G + and NRC Inspection Manual 0609/Appendix B +

Inspection procedure

IP 71111.02 +

Inspection report

IR 05000255/2012002 +

Inspector

D Betancourt +, M Bielby +, A Scarbeary +, K Walton +, Dariusz Szwarc +, John Ellegood +, Alan Dahbur +, Chuck Zoia + and Thomas Taylor +

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>.

19:05:51, 30 September 2017 +

Person