Green. The inspectors identified a Green self-revealing finding for the failure of Exelon personnel to follow procedures related to human performance tools which resulted in the inadvertent opening of a valve on the D13
emergency diesel generator (
EDG). Specifically, Exelon personnel did not correctly identify and maintain a distance barrier from the diesel generator jacket water drain valve during a maintenance activity which resulted in the draining of the jacket water system and unplanned inoperability and unavailability of the D13
EDG. Exelon refilled the jacket water system, restored D13
EDG to an operable condition, and entered the issue into the corrective action program as
IR 3986305. This finding is more than minor because it adversely affected the configuration control attribute of the
mitigating systems cornerstone to ensure the availability of systems that respond to
initiating events to prevent undesirable consequences (i.e. core damage). Specifically, the valve mispositioning caused the D13
EDG to be inoperable and unavailable. Using
IMC 0609, Appendix A, Exhibit 2, the inspectors determined that this finding was of very low safety significance (Green). Specifically, the finding did not represent a loss of system or function and did not represent the loss of a single train for greater than technical specification allowed outage times or greater than
24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />. The inspectors determined that this finding has a cross-cutting aspect in the area of Human Performance, Avoid Complacency, because Exelon personnel did not properly implement error reduction tools. [H.12]
