ENS 56789

v t e ENS Event
04:00 Aug 11, 2023
Title	Part 21 Report - Emergency Diesel Generator Digital Reference Unit Problem
Event Description	The following information was provided by the licensee via email: Donald C. Cook Nuclear Power Plant completed an internal Part 21 evaluation concerning an issue with an Emergency Diesel Generator (EDG) Digital Reference Unit (DRU) supplied by Engine Systems Incorporated (Appendix B Supplier for Woodward Governors). [On August 8, 2023,] a potential defect was identified [during a surveillance test] concerning a marginal solder joint on the DRU electronic circuit board that can result in a loss of continuity between the termination strip and the electronic board, causing a loss of setpoint output from the DRU to the Electronic Governor, and a subsequent loss of fuel to the EDG and inability to support any load. A formal failure analysis is ongoing at the time of this notification. A written notification will be provided within 30 days. Affected known plants include only Donald C. Cook Nuclear Power Plant Units 1 and 2 at the time of notification. The NRC Resident has been notified. The following additional information was obtained from the licensee in accordance with Headquarters Operations Officers Report Guidance: The EDG DRU was replaced after discovery of the potential defect and the EDG is currently operable.

ENS 56789 +/-
Where
Cook Bridgman, Michigan (NRC Region 3)
Organization:	Dc Cook
Reporting

10 CFR 21.21(a)(2), Interim Report for Comply or Defect in Component
Time - Person (Reporting Time:+1496.28 h62.345 days <br />8.906 weeks <br />2.05 months <br />)
Opened:	Steve Mitchell 12:17 Oct 12, 2023
NRC Officer:	John Russell
Last Updated:	Oct 12, 2023
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v • d • e

v t e Emergency Notification System
Cook with 10 CFR 21.21(a)(2), Interim Report for Comply or Defect in Component
WEEKMONTHYEAR2023-08-11T04:00:00 [Table view]
[ENS list for Cook]

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