Protecting People and the EnvironmentUNITED STATES NUCLEAR REGULATORY COMMISSION
UNITED STATES
NUCLEAR REGULATORY COMMISSION
OFFICE OF NUCLEAR REACTOR REGULATION
WASHINGTON, D.C. 20555
March 30, 1992
NRC INFORMATION NOTICE 92-24: DISTRIBUTOR MODIFICATION TO CERTAIN
COMMERCIAL-GRADE AGASTAT ELECTRICAL RELAYS
Addressees
All holders of operating licenses or construction permits for nuclear power
reactors.
Purpose
The U.S. Nuclear Regulatory Commission (NRC) is issuing this information
notice to alert addressees to part modifications and serial number changes
that authorized distributors (ADs) have made to commercial-grade Agastat
Series 7000 electrical relays. These alterations may affect the subsequent
dedication of the relays for safety-related use. It is expected that
recipients will review the information for applicability to their facilities
and consider actions, as appropriate. However, suggestions contained in
this information notice are not NRC requirements; therefore, no specific
action or written response is required.
Description of Circumstances
On April 22, 1991, after being informed by Spectrum Technologies USA,
Incorporated, (Spectrum) that nameplate labels for Agastat Series 7000
relays could have been altered, the NRC staff performed a review of the
manufacture and distribution of those relays. Agastat relays are
manufactured by the Amerace Corporation (Amerace), Livingston, New Jersey,
and its commercial-grade relays are distributed by its authorized
distributors. In early 1991, Spectrum ordered six Agastat Model 7032 PBB
commercial-grade relays from the Westinghouse Electric Supply Company
(WESCO). Spectrum specified in the purchase order that the relays be
traceable to the manufacturer Amerace and that the relays be from the same
lot and date code. Spectrum included these requirements because Spectrum
intended to dedicate the relays for safety-related use. WESCO ordered the
relays from an authorized Amerace distributor, Control Components Supply
(CCS), Short Hills, New Jersey. However, the relays did not have the
required traceability to Amerace because of modifications that CCS made to
the relays, and because of changes CCS made to the serial number nameplates
the relays may not have been from the same production lot.
Amerace representatives have told the NRC that its authorized distributors
are allowed to modify its commercial-grade relays to comply with a
customer's specific requirements. Those modifications may include changing
the electrical
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coil module for different voltage level applications, adding or changing the
electrical contact assembly module, or changing the time duration disc and
wafer.
Amerace personnel have also told the NRC that
(1) The first four digits of the serial number indicate the year and week
of manufacture. The next four digits in the serial number designate
the sequential order of relay assembly for a particular week. For
example, Agastat Model 7012 PC, serial number (S/N) 91161875, was the
1,875th relay to be assembled the 16th week of 1991 at the Amerace
Corporation, Livingston, New Jersey facility. Amerace used similar
marking systems for its subassembly coil and contact modules.
(2) When an AD modifies a commercial-grade 7000 series relay, the AD should
install a new nameplate label with the original S/N containing an "F"
prefix. For example, an AD could change the contact and coil modules
appropriately in the above Model 7012 PC relay and yield a Model 7014
QE relay. However, the S/N on the nameplate should be changed to
F91161875. The F designator would indicate that the relay had been
"field" modified. The NRC staff determined that Amerace did not
contractually state this policy to its ADs (see NRC Inspection Report
No. 99900296/91-01). After the NRC performed its review, Amerace
issued a notification letter to its ADs stating this policy.
Attachment 1 is a copy of the Amerace notification letter.
(3) Before performing the final calibration, test, and acceptance of the
7000 series relays, Amerace heat stabilizes each relay by maintaining
it at a specific temperature for 4 hours. This heat stabilization
mates the timing disc with the ceramic timing wafer to prevent timing
drift and to ensure repeat accuracy. The process also stress-relieves
the nonmetallic parts. Amerace requires that its 7000 series relays be
stabilized again after they are modified such as by changing the timing
disc. To comply with the Agastat model number that was ordered, CCS
changed the timing discs of the six relays that were supplied to
Spectrum. However, the staff found no evidence that the relays had
been restabilized.
Discussion
From October 1991 through January 1992, the NRC staff conducted several
meetings with representatives of Amerace and CCS. The NRC staff found that,
when CCS modifies an Agastat 7000 Series relay, CCS typically removes the
Amerace installed label, assigns the relay a new number, types the new
serial number and other relevant information on a blank label, and affixes
the new label to the modified relay. However, the blank labels that the NRC
staff observed at the CCS facility do not contain the F prefix to indicate
that the 7000 Series Agastat relays were modified. The NRC staff found that
CCS had disassembled, modified, and reassembled the six relays discussed
herein. However, the labels affixed by CCS did not contain the required F
prefix, and the labels did not contain the original Amerace serial number.
CCS had assigned new serial numbers which indicated that the relays were
manufactured in 1991 to reflect
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that the relays had been modified by CCS in 1991. However, Amerace
personnel informed the NRC that the six relays had been manufactured in
1989.
The NRC also found that CCS does not heat stabilize the 7000 Series Agastat
relays that it modifies, although Amerace has stated that the heat
stabilization treatment is necessary on modified 7000 series relays to
ensure repeat accuracy and to relieve the stress to nonmetallic parts. The
NRC staff reviewed CCS's customer list and found that the list contained the
names of 25 NRC nuclear power plant licensees and several other Amerace ADs.
This information suggests that consecutive serial numbers on
commercial-grade Agastat relays, obtained through an authorized distributor,
may not ensure traceability to a particular production lot. Amerace has
stated that its ADs do not heat stabilize the 7000 series relays after they
are modified. As discussed in NRC Inspection Report No. 99900296/91-01,
Amerace told the NRC that there are differences between its Class 1E
qualified relays and its commercial-grade 7000 series relays, such as design
control, internal components, and the level of inspection that is applied.
Similar differences may exist between commercial-grade components and the
safety-related product line of other manufacturers. The availability of a
safety-related product line is often an indicator of substantive differences
from the commercial-grade product. In any case, it is important that
information relied on when upgrading commercial-grade components for use in
safety-related applications be supported by objective evidence of quality to
support the suitability of use of the component.
This information notice requires no specific action or written response. If
you have any questions about the information in this notice, please contact
the technical contact listed below or the appropriate Office of Nuclear
Reactor Regulation (NRR) project manager.
Charles E. Rossi, Director
Division of Operational Events Assessment
Office of Nuclear Reactor Regulation
Technical contact: Joseph J. Petrosino, NRR
(301) 504-2979
Attachments:
1. Amerace Letter on Field Modifications of Agastat Relays
2. List of Recently Issued NRC Information Notices
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