NRC CAL – NOV (White)

On August 3, 2010, the NRC issued a White Significance Determination finding with an associated violation to Calvert Cliffs Nuclear Power Plant (Calvert Cliffs). This White finding involved the licensee's failure to develop and implement scheduled preventive maintenance for Agastat E7000 series time delay relays, as required by Technical Specification 5.4.1. Specifically, subsequent to the approval of Engineering Change Package No. ES200100067, issued in March 2001, the licensee did not replace the relays within the vendor recommended 10-year lifetime, nor establish a performance monitoring program. Consequently, on February 18, 2010, an Agastat E7000 series time delay relay that had a lifetime in excess of 10 years, used in the 2B emergency diesel generator (EDG) protective logic, timed out early and failed to support a demand fast start and run of the 2B EDG. This resulted in the EDG becoming inoperable with the resultant loss of alternating current to the 24 safeguards bus during the dual unit trip that occurred on February 18, 2010.