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The inspectors reviewed a self-revealing, … The inspectors reviewed a self-revealing, non-cited violation of Technical Specification 5.4.1.a for the licensees failure to implement a procedure required by Regulatory Guide 1.33, Revision 2, Appendix A, February 1978. Specifically, System Operating Procedure SOP-0009, Reactor Feedwater System, Revision 63, which is required by Regulatory Guide 1.33, requires the licensee to limit the position of the feedwater regulating valves to less than or equal to 92 percent open to allow for adequate margin to respond to an increase in steam flow while maintaining reactor vessel water level. Contrary to this, on December 12, 2014 while raising reactor power, the licensee failed to maintain the feedwater regulating valves less than or equal to 92 percent open resulting in a steam flow and feedwater flow mismatch and lowering reactor vessel water level, which caused a recirculation flow control valve runback. The crew responded to the runback using approved procedures and restored reactor vessel water level to the correct operating band. This issue was entered in the licensees corrective action program as Condition Report CR-RBS-2014-6357. This performance deficiency is more than minor, and therefore a finding, because it is associated with the human performance attribute of the Initiating Events Cornerstone and adversely affected the cornerstone objective to limit the likelihood of events that upset plant stability and challenge critical safety functions during shutdown as well as power operations. Specifically, the licensee failed to maintain feedwater regulating valves less than or equal to 92 percent open while raising reactor power, which resulted in an unplanned transient when plant systems automatically initiated a recirculation flow control valve runback in response to low reactor vessel water level. Using NRC Inspection Manual Chapter 0609, Appendix A, The Significance Determination Process (SDP) for Findings At-Power, and Inspection Manual Chapter 0609, Appendix A, Exhibit 1, Initiating Events Screening Questions, the inspectors determined that the finding is of very low safety significance (Green) because it did not cause a reactor trip and the loss of mitigation equipment relied upon to transition the plant from the onset of the trip to a stable shutdown condition, high energy line-breaks, internal flooding, or fire. This finding has an avoid complacency cross-cutting aspect within the human performance area because the licensee failed to perform a thorough review of the activity every time the work was performed rather than relying on past successes and assumed conditions. Specifically, the control room operators relied on past experiences rather than following a written procedure (H.12).than following a written procedure (H.12).

Discovered date

23:59:59, 30 September 2015 +

Docket

05000458 +

Equipment trip

Reactor Trip +

Event date

23:59:59, 30 September 2015 +

Finding integer

1 +

Finding type

Non-cited violation +

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INPO aspect

QA.4 +

Identified by

Self-revealing +

Inspection Manual Chapter

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

Inspection procedure

IP 71153, Event Followup +

Inspection report

IR 05000458/2015003 +

Inspector

J Sowa +, Paul Elkmann +, Nicholas Hernandez +, Greg Warnick + and Benjamin Parks +

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12:58:19, 25 September 2017 +

Person