Title
10 CFR 50 Appendix B, Criterion V, requires, in part, that licensees shall perform activities affecting quality in accordance with instructions appropriate to the circumstances. Contrary to the above, on May 10, 2016, the licensee failed to perform safety chiller maintenance, a quality related activity, in accordance with the approved instructions. Specifically, licensee personnel failed to
torque electrical connections on
overload relays on the unit 1 train A safety chiller as required by the licensees work instructions. The inadequate
torque was present until June 9, 2016, when the licensee performed
thermography on the chiller electrical connections. The licensee discovered elevated temperatures, shut down the chiller, and replaced and torqued the affected components. The licensee determined that the chiller was
inoperable from May 28, 2016, when it was required to be in service due to the unit entering Mode 4, until the chiller was restored on June 9. The violation is more than minor because it affected the equipment performance attribute of the
Mitigating Systems cornerstone and impacted the cornerstone objective to ensure the availability, reliability, and capability of systems that respond to
initiating events to prevent undesirable consequences. Using
Inspection Manual Chapter 0609, Attachment 04, Initial Characterization of Findings, and
Inspection Manual Chapter 0609, Appendix A, The
Significance Determination Process for Findings At-Power, the inspectors determined that the violation required a detailed risk evaluation (
DRE) because the finding represented a loss of function of a single train for greater than its technical specification allowed outage time. A senior reactor analyst from Region IV performed the risk evaluation. The licensee provided an analysis demonstrating that the chiller would be able to perform its safety function for at least
24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />. Based on that demonstration, the analyst was able to determine that the risk was of very low safety significance (Green). The violation was entered into the licensees corrective action program as CR-2016-005798.
