The following is a summary of the report provided by the notifier:
Pursuant to 10 CFR 21.21(d)(3)(ii), Nutherm International, Inc. is providing written notification of the identification of a potential defect found in Eaton D26 relays.
On July 23, 2019, Eaton Corporation released a letter, 'Update on Reports of Size 1 & 2 AC Contactors that Failed to Open When Deenergized'. This letter described a condition observed on AC contactors after being energized for a long period of time without being 'cycled'. Eaton also stated that this would occur in only a few isolated cases in continuously energized applications.
The cause of the problem is the coating on each of the steel laminations in the cores of these devices. This steel is coated with an organic insulating varnish classified as C3. This coating, when heated for a long time period, can migrate from the lamination surfaces to the edges at the area between the separate core pieces (referred to as armatures and magnets). This substance is sticky and can potentially hold the core pieces together with enough strength to overcome the forces of the device's return springs.
Potentially impacted components may include:
Freedom contactors NEMA Size 00 through 5
A200 contactors NEMA Size 00 through 4
D15 Relays
D26Relays
AR Relays (AC Only)
BF Relays (AC Only and including NBF relays)
Vacuum contactors NEMA Size 4
Nutherm identified that they had supplied the Eaton relays to the following facilities:
Dresden Nuclear Station
Quad Cities Nuclear Station
Palisades Nuclear Power Plant
HB Robinson Steam Electric Plant
Point Beach Nuclear Plant
If you have any questions please contact Adrienne Smith at 618-244-6000, extension 3034, email adrienne.smith@nutherm.com or Kyle Mitchell at 618-244-6000, extension 3097 email kyle.mitchell@nutherm.com.