Protecting People and the EnvironmentUNITED STATES NUCLEAR REGULATORY COMMISSION
SSINS No.: 6835
IN 86-65
UNITED STATES
NUCLEAR REGULATORY COMMISSION
OFFICE OF INSPECTION AND ENFORCEMENT
WASHINGTON, D.C. 20555
August 14, 1986
Information Notice No. 86-65: MALFUNCTIONS OF ITT BARTON MODEL 580
SERIES SWITCHES DURING REQUALIFICATION
TESTING
Addressees:
All nuclear power reactor facilities holding an operating license or a
construction permit.
Purpose:
This notice is provided to alert recipients to a potentially significant
safety problem pertaining to malfunctions of ITT Barton Model 580 Series
indicating switches under accident conditions. It is expected that
recipients will review the information for applicability to their facilities
and consider actions, if appropriate, to preclude malfunctions occurring at
their facilities. However, suggestions contained in this notice do not
constitute NRC requirements; therefore, no specific action or written
response is required.
Description of Problem:
On April 14, 1986, NRC was notified by ITT Barton Instruments Company of the
defect in accordance with 10 CFR Part 21. According to the report, during
requalification testing of ITT Barton Model 580 Series indicating switches
under loss-of-coolant accident conditions, switch malfunctions occurred when
the chamber temperature was raised to 340F. The symptoms of the
malfunctions were:
- In three of the five instruments tested, one or both of the
switches failed to operate (no change in switch state) when input
pressure to the instrument was varied.
- Switch set-point shift in excess of the allowable 10 percent
occurred on two of the instruments.
When the chamber temperature was lowered to room ambient, all of the
switches changed state when input pressure was varied; however, the switch
setpoint shifts which occurred at temperature were permanent.
The initial report indicated that the failure was due to a specific
component used, a Honeywell Snap-Acting Switch, part number IISM 403. A
subsequent report indicated that, as a result of additional testing, it was
determined that there is also a deflection of the instrument case
which affects the position of the snap switch and the setpoint. Furthermore,
the deflection can result in failure of case seal integrity.
8608120032
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IN 86-65
August 14, 1986
Page 2 of 2
ITT Barton has indicated that they are evaluating case/seal redesigns and a
realistic date for completion of retesting would be April 15, 1987.
In previous tests, the instruments performed successfully when subjected to
220F after aging, irradiation, and seismic testing.
This information notice is being issued to ensure that all nuclear power
plant end-users have been notified of this problem.
A contact at ITT Barton Instruments Company knowledgeable of this problem
is:
John P. Doyon
Manager, Sales and Service
(818) 961-2547 extension 456
No specific action or written response is required by this information
notice. If you have any questions about this matter, please contact the
Regional Administrator of the appropriate regional office or this office.
Edward L. Jordan Director
Division of Emergency Preparedness
and Engineering Response
Office of Inspection and Enforcement
Technical Contact: Eric Weiss, IE
(301) 492-9005
Pentti Koutaniemi, IE
(301) 492-9428
Attachments: List of Recently Issued IE Information Notices
