Part 21 Report - 1995-222
ACCESSION #: 9510310202
Automatic Switch Co. Manufacturers of ASCO
FLORHAM PARK, NEW JERSEY 07932 o N.J.-(201) 966-2000 / N.Y.-(212) 344-
October 24, 1995
U.S. Nuclear Regulatory Commission
Washington, DC 20555-0001
ATTN: David Skeen, NRR/PECB
MAIL STOP: 0-11A1
Subject: Request for technical review of draft information notice
regarding failure of main steam isolation valves caused by
sticking solenoid pilot valves
Dear Mr. Skeen,
This will respond to the October 18, 1995 letter I received from
Alfred E. Chaffee, Chief Events Assessment and Generic Communications
Branch, concerning the subject information notice draft. After review of
this draft we have the following comments:
1. Please consider adding a statement that extensive testing by
ASCO of Nyogel 775A lubricant and similar silicone lubricants
has shown no potential for them to develop the sticking forces
necessary to prevent the shifting of ASCO NP8323 valves.
Additionally, to our knowledge, no testing by utilities or
others has ever indicated a propensity for these lubricants to
develop any significant adhesion force. However, testing by
ASCO, G.E., and others has confirmed that Loctite PST 550 and
Neolube 100 thread sealants both have the potential to prevent
shifting of a typical solenoid valve.
2. We would like to see a statement added to the information
notice indicating that all NP8323 valves supplied by ASCO (from
the time they were first introduced to the time when their
manufacture was discontinued) incorporated silicone lubricants.
However, ASCO never used Loctite PST 550, Neolube 100 or any
similar anaerobic sealants in the manufacture of these valves.
It should also be noted that LaSalle uses Loctite PST to seal
pipe threads in their air supply system, and used Loctite PST
to seal the thread connections on some of the failed valves.
3. The third paragraph on page two states, "Prior to installation,
LaSalle returned the valves to ASCO for inspection and
cleaning, and some lubricant was found on one of the returned
valves". Some of us interpreted this sentence to mean that
lubricant was found in the valves after they were cleaned by
ASCO, when in fact we believe the sentence is meant to indicate
that lubricant was found in one of the valves supplied to ASCO
for inspection prior to its cleaning. For this reason, we
would like to see this sentence reworded to make it clear that
no lubricant was found subsequent to the cleaning by ASCO.
4. Please consider adding a statement that ASCO issued a field
notification in 1989 advising that we would discontinue the
manufacture of NP8323 valves. That notification recommended
that utilities remove NP8323 valves from MSIV piloting
applications as soon as possible, consistent with normal plant
operation and maintenance schedules. Additionally, please
consider adding that ASCO issued a field notification in 1995
recommending that any plant who is continuing to use the NP8323
valves reconsider this position. I believe you already have
copies of both of these notifications.
David Skeen -2- October 24, 1995
We appreciate the opportunity you have given us to provide input
into this information notice draft. Please feel free to contact me if you
would like to discuss any of our comments.
AUTOMATIC SWITCH COMPANY
John R. Shank
New Product Design & Development
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