Information Notice No. 85-17, Supplement 1: Possible Sticking of ASCO Solenoid Valves
SSINS No.: 6835
IN 85-17, Supplement 1
NUCLEAR REGULATORY COMMISSION
OFFICE OF INSPECTION AND ENFORCEMENT
WASHINGTON, D.C. 20555
October 1, 1985
Information Notice No. 85-17, SUPPLEMENT 1: POSSIBLE STICKING OF ASCO
All nuclear power reactor facilities holding an operating license (OL) or a
construction permit (CP).
This notice is to inform recipients of the results of followup
investigations regarding the reasons for sticking of Automatic Switch
Company (ASCO) solenoid valves used to shut main steam isolation valves
(MSIVs) under accident conditions. Recipients are expected to review the
information for applicability to their facilities and consider actions, if
appropriate, to preclude similar problems occurring at their facilities.
However, suggestions contained in this information notice do not constitute
NRC requirements; therefore, no specific action or written response is
Description of Circumstances:
Information Notice No. 85-17, "Possible Sticking of ASCO Solenoid Valves,"
described the problem that occurred with ASCO Model HTX 832320V solenoid
valves at Grand Gulf Unit 1.
General Electric (GE) and ASCO conducted tests to determine the cause and
any further corrective actions. The following is a summary of the GE and
ASCO tests and analyses:
Two of the three solenoid valves which failed at the Grand Gulf Nuclear
Station also sporadically failed to transfer during testing at elevated
temperatures. These two valves were the only valves that failed during
these tests. However, these failures were not predictable.
Subsequently, five valves from Grand Gulf service were disassembled and
inspected. This inspection identified a microscopic foreign substance
on the lower core/plug nut interfaces on all five valves.
Further evaluations of this microscopic substance were inconclusive
because of the small foreign substance sample size. After cleaning and
reassembly of these valves, tests were conducted on four of these five
valves at elevated temperatures. These four valves functioned normally.
ASCO felt certain that the valve failures resulted from
high-temperature sticking of the lower core-to-plug nut faces resulting
from a foreign substance or combination of substances collected at this
IN 85-17 Supplement 1
October 1, 1985
Page 2 of 2
A detailed dimensional analysis and comparison among the valves
returned from Grand Gulf indicated that all parts were within allowable
limits and differences were not enough to cause a failure to shift.
Therefore, this examination tended to relieve concerns related to a
generic design defect.
GE has attempted to locate additional foreign substance from other
valves of the same type in use at Grand Gulf to determine how the
foreign substance got in the valve, or where it originated. GE was able
to scrape some small amounts of foreign substance from the lower
core-to-plug nut interface. However, there was not enough residue to
make a definitive identification of the nature of the foreign
GE has recommended that the licensee replace the potentially contaminated
MSIV solenoid valves and institute a periodic examination and cleaning of
the MSIV solenoid valves. Grand Gulf has replaced the eight MSIV HTX832320V
dual solenoid valves with fully environmentally qualified ASCO Model NP
8323A20E dual solenoid valves. The environmentally qualified valve Model NP
8323A20E was included in a control sample placed in the test ovens with the
solenoid valves that stuck at Grand Gulf. The environmentally qualified
model did not stick under the test conditions that cause sticking in the
other solenoid valves.
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
Attachment: List of Recently Issued IE Information Notices
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