Bulletin 71-01: Niagara Mohawk Power Corporation


                                                        IEB 71-01

                                                        November 24, 1971

                            DIVISION OF COMPLIANCE
                                   REGION 1
                               970 BROAD STREET
                           NEWARK, NEW JERSEY 07102

Niagara Mohawk Power Corporation
Attention:  Mr. F.J. Schneider, Vice President-Operations
300 Erie Boulevard West
Syracuse, New York 13202


We recently received information, from a licensee operating a boiling water
reactor, which may relate to the performance of the main steam isolation
valves in your facility.  The information is as follows:

During a planned test, one main steam isolation valve failed to close fully
due to interference in the hydraulic dash pot (Model N2K) of the valve
operator caused by a segment of a broken cushion spud.  The valve was an air
operated Atwood and Morrill valve with a Hydro-Line Manufacturing Company
operator (Model 612-003-1B).  The licensee's investigation of the condition of
the other valve operators for the main steam isolation valves in the plant
disclosed that one additional operator had a cracked cushion spud.

It is requested that you provide this office within 10 days, in writing, with
the following information:

a.  Whether valve(s) equipped with the described make and model operator are
installed in a safety system of your facility.

b.  If the answer to the above question is in the affirmative, provide the
date when each valve operator will be inspected.

c.  If the results of the inspection indicate the existence of the deficiency
described above, submit the specific findings from your inspection to this
office within 10 days from the date of the inspection, together with the
description of the corrective action taken or planned, including the scheduled
completion date of your planned action.

Should you have any questions concerning this matter, we will be pleased to
discuss them with you.

                                              Very truly yours,

                                              James P. O'Reilly

cc:  A. Burt, Station Superintendent 


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