In accordance with
10CFR21.21(d)(3), initial notification of a reportable defect is being made by James A. Fitzpatrick (JAF).
The failure of two General Electric (GE) IRMA auxiliary relays in a short period of time were identified in the corrective action system as a potential common mode failure. Initial troubleshooting revealed that both relay coils indicated open. There was no evidence of any obvious cause for the coils to open circuit (e.g. discoloration, smell, physical damage). Both relays are normally de-energized relays located in a mild environment in the relay room (controlled humidity, no vibration at the panels, no local heat source that could cause accelerated aging). Both relays were installed in 1988 along with 21 other relays. A total of 33 relays were purchased from GE with the same lot/date code.
An extent of condition review was conducted. By checking the continuity of related relay coils, two other coil failures were detected. A failure analysis of the relays was performed. The failure mode was determined to be an open in the coil due to corrosion of the coil wire. This open in the coil will prevent the relay from changing state as the relay is energized. An independent laboratory concluded that the coil insulation was damaged and that the under lying wire was damaged during coil manufacture. The damage allowed the copper wire to corrode over the years to the point of failure.
These HMA relays were installed in multiple Emergency Core Cooling Systems (ECCS) and other systems. Each component was evaluated to determine the specific impact on the respective system. The systems affected included: Residual Heat Removal (RHR, the Low Pressure Coolant Injection (LPCI) mode of operation), Emergency Diesel Generators (EDGs), Automatic Depressurization System (ADS), Reactor Core Isolation Cooling (RCIC), Core Spray (CS), and High Pressure Coolant Injection (LPCI).
JAFs evaluation concluded that a substantial safety hazard existed in that there was a potential for a major deficiency/major degradation of essential safety-related equipment, specifically for the RHR (LPCI mode of operation) and HPCI systems.
No other safety functions would have been lost for the other identified systems.
Component and Supplier:
GE HMA Type auxiliary relays
GE Part No. 12HMA124A2
GE Dwg No. DA137C6164P001
Date Code 14VC; 8836
Serial #s: D88542-0001D R02 through D88542-0033D R02
All were purchased as safety-related from GE under JAF PO # 88-5628
All installed safety-related relays from this lot were replaced during the recent refueling outage.
The licensee notified the NRC Resident Inspector.
