ENS Event | |
|---|---|
05:00 Apr 21, 2010 | |
| Title | High Failure Rate of Normally Energized Electro-Pneumatic Time Delay Relays |
| Event Description | The following was received via facsimile:
Waterford 3 has observed a higher than expected failure rate of normally energized Tyco model E7024PB electro-pneumatic time delay relays produced since 2007. Seven of the eight failures were observed on 2007 or newer date code relays and one was observed on a 2004 date code relay. Waterford 3 had 33 Tyco model E7024PB time delay relays installed in the plant. The Agastat E7000 series timing relay consists of two basic operating types, On-Delay and Off-Delay. The On-Delay models provide a delay period of contact re-positioning on energization and no time delay upon de-energization. The Off-Delay models provide a delay period of contact re-positioning on de-energization and no time delay upon energization. These relays may be ordered with various electrical characteristics suitable for use specific to each application. The early-in-life failures have been observed on Tyco model E7024PB relays designed as an Off-Delay, 4 pole double throw, 125 VDC operating coil, with a time delay range of 0.5 to 5 seconds. All failed relays were replaced. Post failure bench testing at Waterford 3, Tyco, or independent Failure Analysis has not consistently repeated the failures. See EN#44684 for Part 21 reported by Tyco Electronics. |
| Where | |
|---|---|
| Tyco Electronics Killona, Louisiana (NRC Region 4) | |
| Organization: | Waterford Steam Electric Station |
| Reporting | |
| 10 CFR 21.21 | |
| Time - Person (Reporting Time:+5.58 h0.233 days <br />0.0332 weeks <br />0.00764 months <br />) | |
| Opened: | William Hardin 10:35 Apr 21, 2010 |
| NRC Officer: | Dong Park |
| Last Updated: | Apr 21, 2010 |
| 45862 - NRC Website | |
Tyco Electronics with 10 CFR 21.21 | |
WEEKMONTHYEARENS 458622010-04-21T05:00:00021 April 2010 05:00:00
[Table view]10 CFR 21.21 High Failure Rate of Normally Energized Electro-Pneumatic Time Delay Relays ENS 446842008-09-28T05:00:00028 September 2008 05:00:00 10 CFR 21.21 Relay Failed to Actuate as a Result of Incorrect Recyle Spring ENS 432182007-03-05T05:00:0005 March 2007 05:00:00 10 CFR 21.21 Potential Defect in E7000 Relays 2010-04-21T05:00:00 | |