ENS 48223
ENS Event | |
|---|---|
04:00 Aug 22, 2012 | |
| Title | Part 21 - Defect Due to Change in Manufacturing Process Causing Relay Failure in Safety Related Systems |
| Event Description | The following is summary of the information received from the licensee:
The basic component is an Eaton-Cutler Hammer Type ARD660UR DC relay that is commercially dedicated by Westinghouse for use in safety related systems at Palo Verde Units 1, 2 and 3. Except for the Palo Verde plants, Westinghouse is not aware of any other plant that uses this relay as a safety-related component in normally energized applications. The relay contacts failed to change state when required to do so during postulated events and/or surveillance testing. Westinghouse has identified the kick-out spring as a possible contributing factor for the relay failure due to stress corrosion cracking. Other anomalies such as relay core barrel tolerance and potential material deficiencies are currently under review. Based upon testing at APS, the relay failure rate is low and non-reproducible. This indicates that a combination of factors could be resulting in the failures with different causes for each failure. Results of testing do not identify a common cause for the failures. For ARD660UR relays used in normally de-energized applications, the kick-out spring will be compressed for only a short period of time and exposure to additional heat generated by intermittent coil energization will be minimal. For relays in normally de-energized applications, it is not expected that the force provided by the kick-out spring will decrease significantly over time and the contacts will change position when the relay coil is de-energized. Westinghouse has not received any reports to date of relay contacts failing to properly change position when the relay goes from a de-energized to an energized state. Because of the kick-out spring's limited exposure to compression and heat generated by the relay coil, it is expected that the springs will perform as intended in normally de-energized applications for the qualified life of the relay. Identification of the firm constructing the facility or supplying the basic component which fails to comply or contain a defect. Westinghouse Electric Company 1000 Westinghouse Drive Cranberry Township, Pennsylvania 16066
The following update was received via fax and is summarized below: During the investigation into the cause of the ARD660UR relay sticking, many physical and performance aspects and components of the relay were analyzed, as well as the entire manufacturing process. This investigation uncovered several issues that contributed, or could contribute, to the failure of the relay to release when de-energized. Based on analysis by Westinghouse, with support from Eaton Corporation, it was determined that the primary cause of the relay failure was a change in the manufacturing process in the plastics molding operation of this relay. This manufacturing change caused the moving cores to adhere to the inner diameter of the relay coil spool when a relay was continuously energized during testing by Westinghouse for longer than 21 days. This change in the manufacturing process began in May 2008 and continued until it was terminated in December 2012. Relay coils manufactured during this time may develop an adhesive like residue in the relay coil spools when energized for an extended period of time. This residue was found on the moving cores of relays which stuck during testing at a Westinghouse facility and relays returned from the customer. This residue was determined to be the primary cause of the relay issue. Westinghouse shipped Palo Verde a total of 374 potentially affected Eaton-Cutler Hammer Type ARD660UR DC relays. As a result of the investigation, Westinghouse recommended several manufacturing process improvements that are designed to prevent the reoccurrence of the issue. Eaton has agreed to implement these improvements prior to restarting the manufacture of these relays. Westinghouse is revising its commercial grade dedication process for these relays. This action ensures that the commercial grade dedication criteria include replacing the relay kick-out spring in each relay and verifies other relay enhancements have been implemented before future relays are shipped to the customer as safety related components. Westinghouse recommends that each plant review the application requirements of each affected relay. If an ARD660UR relay is used in a normally energized application or is required to change state after being energized for at least 21 consecutive days and was manufactured between May 1, 2008 and December 31, 2012, Westinghouse recommends replacing the relay at the next convenient opportunity. If an ARD relay manufactured during the May 1, 2008 and December 31, 2012 time frame is successfully, periodically cycle tested, this relay may be less susceptible to sticking. Notified R4DO (Deese) and NRR Part 21 Group via email. |
| Where | |
|---|---|
| Westinghouse Electric Company Cranberry Township, Pennsylvania (NRC Region 1) | |
| Organization: | Westinghouse Electric Company |
| Reporting | |
| 10 CFR 21.21(d)(3)(i), Failure to Comply or Defect | |
| Time - Person (Reporting Time:+29.35 h1.223 days <br />0.175 weeks <br />0.0402 months <br />) | |
| Opened: | James Gresham 09:21 Aug 23, 2012 |
| NRC Officer: | Dong Park |
| Last Updated: | Apr 8, 2013 |
| 48223 - NRC Website | |
Westinghouse Electric Company with 10 CFR 21.21(d)(3)(i), Failure to Comply or Defect | |
WEEKMONTHYEARENS 558362022-04-06T04:00:0006 April 2022 04:00:00
[Table view]10 CFR 21.21(d)(3)(i), Failure to Comply or Defect Part 21 - Westinghouse Actuator Full Voltage Reversing Contactors Deficency Report ENS 531932018-01-26T06:00:00026 January 2018 06:00:00 10 CFR 21.21(d)(3)(i), Failure to Comply or Defect Part-21 Notification - Improper Lugs in a Breaker Cubicle ENS 502792014-07-14T04:00:00014 July 2014 04:00:00 10 CFR 21.21(d)(3)(i), Failure to Comply or Defect Part 21 Report - Potential Failure of Reactor Coolant Pump Turning Vane Bolts ENS 512982013-10-23T16:00:00023 October 2013 16:00:00 10 CFR 21.21(d)(3)(i), Failure to Comply or Defect Part 21 - Damaged Surveillance Capsules ENS 492172013-07-26T04:00:00026 July 2013 04:00:00 10 CFR 21.21(d)(3)(i), Failure to Comply or Defect Potential Existence of Defects in Shield Passive Thermal Shutdown Seal System ENS 482232012-08-22T04:00:00022 August 2012 04:00:00 10 CFR 21.21(d)(3)(i), Failure to Comply or Defect Part 21 - Defect Due to Change in Manufacturing Process Causing Relay Failure in Safety Related Systems 2022-04-06T04:00:00 | |