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Home NRC Library Document Collections Events, Reports Associated with Part 21 Reports 1995

Part 21 Report - 1995-222

ACCESSION #: 9510310202

Automatic Switch Co.                    Manufacturers of         ASCO
                                       DEPENDABLE CONTROL
                                            Since 1888

FLORHAM PARK, NEW JERSEY 07932 o N.J.-(201) 966-2000 / N.Y.-(212) 344-
3765 FAX-966-2628

                                   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
NRC

     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.

                                        Sincerely,

                                        AUTOMATIC SWITCH COMPANY

                                        John R. Shank
                                        Director
                                        New Product Design & Development
/ja

                                                               Skeen. doc

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