Information Notice No. 82-48: Failures of AGASTAT CR 0095 Relay Sockets
SSINS No.: 6835
NUCLEAR REGULATORY COMMISSION
OFFICE OF INSPECTION AND ENFORCEMENT
WASHINGTON, D. C. 20555
December 3, 1982
Information Notice No. 82-48: FAILURES OF AGASTAT CR 0095 RELAY SOCKETS
All holders of a nuclear power reactor operating license (OL) or
construction permit (CP).
This information notice is provided as an early notification of a
potentially significant problem pertaining to Agastat CR 0095 Relay Sockets
manufactured by Amerace Corporation Control Products Division in Union, New
Jersey. Because of the potential safety significance and related generic
implications of this problem, addressees are expected to review the
information for applicability to their facilities. No specific action or
response is required at this time.
Description of Circumstances:
Since 1978 several deficiencies on Agastat CR 0095 relay sockets have been
1. On December 21, 1978, Northern States Power Company submitted a
Licensee Event Report (LER) for the Monticello nuclear facility. While
performing a surveillance test during normal operation, a high pressure
instrument channel relay failed to energize. A CR 0095 Agastat relay
socket contact was disengaged from the socket and not making contact
with the mating Agastat relay contact.
2. On January 5, 1979, Alabama Power Company submitted an LER for Farley
1 nuclear plant. During a diesel generator operability test, while at
100% power level, a sequencer failed to pick up Step 6 (battery
charger). After the Agastat relay socket was replaced, the test was
3. On April 6, 1979, Northern States Power Company submitted an LER for
the Monticello nuclear facility. During a surveillance test a motor
generator field breaker trip relay failed to trip the breaker. A CR
0095 Agastat relay socket contact was disengaged from the socket and
not making contact with the mating Agastat relay contact.
4. On December 7, 1979, Detroit Edison submitted a 10 CFR 50.55(e) report
No. EF 2-50-658 for the Enrico Fermi 2 nuclear facility. In their two
primary containment monitoring system cabinets, problems were
December 3, 1982
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Agastat relay assemblies. When the relays are plugged into the socket,
the terminals are pushed back and this sometimes results in no contact
between the relay pin and the socket terminal.
5. On June 11, 1981, Florida Power Corporation submitted an LER for
Crystal River 3 nuclear facility. During a monthly functional test of
engineered safeguards, the load sequence block 3 trip circuit would not
reset following the actuation test. The cause was identified as a loose
connection in the Agastat relay mounting block.
Several more LERs since 1978 identified problems of similar nature but did
not specifically identify the Agastat relay socket as the problem; however,
the type of failure in specific circuits indicates that the Agastat relay
socket may be the cause.
During early 1979 the General Electric Company (GE), Nuclear Energy Business
Operation (NEBO), tested more than 2200 Agastat CR 0095 relay sockets and
found that a significant number of sockets tested exibited contact retention
problems and potential electrical connection problems. As a result of this
test and subsequent evaluations; GE, NEBO made recommendations to its
In February 1979 the Amerace Corporation, Control Products Division
redesigned and modified the relay base molding by:
1. Providing a better guide for the relay male contact into the base
(socket) female contact.
2. Providing a female contact support behind the female contacts to
prevent a push-back.
3. Redesigning and modifying the "fast-on" terminal on the relay base.
These modified Agastat relay sockets were available from the Amerace
Corporation in the latter part of February 1979 and all Agastat CR 0095
relay sockets shipped during and after March 1979 were of the redesigned and
Another means of correcting the problem which has been found to be effective
is the installation of cardboard insulator strips behind the relay sockets.
These strips are available from the Amerace Corporation.
Agastat CR 0095 relay sockets are used in PWRs as well as in BWRs. While
most of the nuclear plant owners of BWRs have been made aware of this
problem by GE-NEBO not all PWR owners are aware or were informed of this
problem and its resolution.
December 3, 1982
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If you have any questions regarding this matter please contact the
administrator of the appropriate NRC Regional Office.
Edward L. Jordan, Director
Division of Engineering and
Office of Inspection and Enforcement
Technical Contact: W. Laudan
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