ENS 54306
ENS Event | |
|---|---|
21:30 Oct 1, 2019 | |
| Title | Part 21 Report - Ite/Gould J20M Coil Block Relay |
| Event Description | On October 1, 2019, the Arkansas Nuclear One (ANO) Site Vice President was notified of a defect on an ITE/Gould J20M Coil Block Relays which met the reporting criteria of 10 CFR 21.21.
ANO is making this non-emergency notification in accordance with 10 CFR 21.21(d)(3)(I) concerning a defect on an ITE/Gould J20M Coil Block Relay which resulted in one of four safety related containment cooling fans failure to start at ANO Unit 2. On June 1, 2019, a failure occurred when the containment cooler fan hand switch was taken to 'start' during the recent Unit 2 forced outage. Troubleshooting identified the control power relay coil was found to have an open winding condition. The Unit 2 reactor was in shutdown (Mode 5) and no impacts to nuclear or radiological safety occurred because of this event. The failure of the containment cooling fan to start would have prevented the Containment Cooling System from performing its function of providing essential cooling/environmental controls for safety related equipment inside containment. On August 15, 2019, ANO approved a causal evaluation which determined the failure of the relay occurred due to a manufacturing defect associated with uneven varnish application on the coil windings. This defect lead to premature turn-to-turn shorting of the coils. This failure was determined to be limited to ITE/Gould relays that were part of a 1991 batch purchased by ANO. The 1991 relay batch had a manufacturing date code of 9132. As part of the ANO evaluation, an industry operating experience review identified INPO ICES OE 242045. This OE identified another utility had purchased three relays from ANO in 2007 and subsequently experienced coil failures on two of the three relays. The utility did not issue a 10 CFR Part 21 notification. During the ANO evaluation, NRC IN 92-27 Supplement 1 was reviewed. The IN noted the same component failure mode. However, the failure mechanism was different. The IN discussed failures associated with thermal degradation of the relay armature carriers in ganged mounting configurations. The failure mechanism at ANO is due to uneven varnish application to the coil windings. Entergy ANO performed a Part 21 Evaluation in accordance with 10 CFR 21.21(a)(1) which was completed on September 25, 2019. This evaluation determined this defect could create a substantial safety hazard as defined in 10 CFR 21.3. The licensee has two relays left that could be affected. One relay is installed and currently in use by the other containment cooling fan and the other relay is on parts hold in an ANO onsite warehouse. A Condition Report has been initiated to document the potential for failure of the installed control power relay. This ITE/Gould J20 is obsolete and other options are being evaluated to replace the ITE/Gould J20M Coil Block Relay. ANO has notified the utility to whom it sold the relays in 2007. ANO has also notified the vendor. The licensee notified the NRC Resident Inspector. |
| Where | |
|---|---|
| Curtis Wright London, Arkansas (NRC Region 4) | |
| Organization: | Arkansas Nuclear |
| Reporting | |
| 10 CFR 21.21(d)(3)(i), Failure to Comply or Defect | |
| Time - Person (Reporting Time:+14.12 h0.588 days <br />0.084 weeks <br />0.0193 months <br />) | |
| Opened: | Donna Boyd 11:37 Oct 2, 2019 |
| NRC Officer: | Ossy Font |
| Last Updated: | Oct 2, 2019 |
| 54306 - NRC Website | |
Curtis Wright with 10 CFR 21.21(d)(3)(i), Failure to Comply or Defect | |
WEEKMONTHYEARENS 543062019-10-01T21:30:0001 October 2019 21:30:00
[Table view]10 CFR 21.21(d)(3)(i), Failure to Comply or Defect Part 21 Report - Ite/Gould J20M Coil Block Relay 2019-10-01T21:30:00 | |