ENS 45862

v t e 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.

ENS 45862 +/-
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
v • d • e

v t e Emergency Notification System
Tyco Electronics with 10 CFR 21.21
WEEKMONTHYEAR2010-04-21T05:00:00 [Table view]
[ENS list for Tyco Electronics]

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