Protecting People and the EnvironmentUNITED STATES NUCLEAR REGULATORY COMMISSION
SSINS No.: 6835
IN 83-57
UNITED STATES
NUCLEAR REGULATORY COMMISSION
OFFICE OF INSPECTION AND ENFORCEMENT
WASHINGTON, D.C. 20555
August 31, 1983
Information Notice No. 83-57: POTENTIAL MISASSEMBLY PROBLEM WITH
AUTOMATIC SWITCH COMPANY (ASCO) SOLENOID
VALVE MODEL NP 8316
Addressees:
All nuclear power reactor facilities holding an operating license (OL) or
construction permit (CP).
Purpose:
This information notice is issued to alert licensees to a potential problem
with ASCO three-way solenoid-operated pilot valves, type NP-8316 in 3/8" and
1/2" NPT sizes. Should a 1978 version of the manufacturer's installation
instruction bulletin be followed, certain parts of the subject solenoid
valves would be incorrectly assembled. Such misassembly can lead to air
leakage past the valve seat of the affected valve, although the valve would
still operate. No specific action or response is required at this time.
Description of Circumstances:
Franklin Research Center (FRC) in Philadelphia, Pennsylvania is under
contract to the NRC to perform an independent testing and analysis program
pertaining to ASCO solenoid valves. During the analysis phase, FRC noticed
that the original ASCO Installation and Maintenance Instruction (Form
V-5967) for Bulletin NP-8316 valves pictured the pressure and exhaust
diaphragm assemblies backwards. The diaphragm assemblies should be
positioned so that the large metal washer faces the bonnet and the small
washer faces the body; this seats the surface of the diaphragm against the
valve body (see attached diagram).
ASCO informed the NRC that NP-8316 valves were always assembled correctly in
the factory and most maintenance personnel will install new diaphragms as
they were installed before and not in accordance with the picture in Form
V-5967. ASCO has also indicated that despite the FRC report, no problems of
this nature have been reported in the field.
The ASCO Installation and Maintenance Instructions, Form V-5967, was issued
in 1978 and superseded by revised Form No. V-5967R1, published in 1981. The
latter shows the correct orientation of both diaphragms. It is possible that
during these three years some maintenance crews used the picture on the
original ASCO Form V-5967 instructions for maintenance, installing the
diaphragms backwards instead of replacing them in the same orientation as
they had been removed.
8308040043
.
IN 83-57
August 31, 1983
Page 2 of 2
ASCO assured the NRC that valves with the diaphragms installed backwards
will still operate, but that the valves would leak. Therefore, this error
may go unnoticed, if the valves were not operated be being returned to
service.
These valves are used extensively in safety-related systems at both BWR and
PWR nuclear power plants. Although no written response to this notice is
required, it is suggested that holders of OLs or CPs review this information
notice for applicability at their facilities. If you have any questions
regarding this matter, please contact the Regional Administrator of the
appropriate NRC Regional Office, or this office.
Edward L. Jordan Director
Division of Emergency Preparedness
and Engineering Response
Office of Inspection and Enforcement
Technical Contact: W. Laudan, IE
(301) 492-9759
Attachments:
1. Valve Diagram
2. List of Recently Issued IE Information Notices
.
