Results of the Public Workshops (Generic Letter 89-10, Supplement 1)
June 13, 1990
TO: ALL LICENSEES OF OPERATING NUCLEAR POWER PLANTS AND HOLDERS OF
CONSTRUCTION PERMITS FOR NUCLEAR POWER PLANTS, AND INDIVIDUALS
ON THE ATTACHED DISTRIBUTION LIST
SUBJECT: SUPPLEMENT 1 TO GENERIC LETTER 89-10: RESULTS OF THE PUBLIC
WORKSHOPS
In September 1989, the NRC staff held three public workshops to discuss
Generic Letter 89-10, "Safety-Related Motor-Operated Valve Testing and
Surveillance." This generic letter, issued on June 28, 1989, requests
holders of nuclear power plant operating licenses and construction permits
to establish a program to provide for the testing, inspection, and
maintenance of safety-related motor-operated valves (MOVs) and certain other
MOVs in safety-related systems. Attached for the use of licensees and
construction permit holders are the results of the public workshops.
This supplement to Generic Letter 89-10 includes the opening remarks by NRC
representatives and the responses provided by the NRC staff to all
significant questions. These responses reflect the best information
currently available to the staff from research and operating experience
regarding the operability of MOVs under design-basis conditions. For
example, the staff believes that, at the present time, the most reliable
means of demonstrating operability of an MOV under design-basis conditions
is to perform a test of the MOV in situ under those conditions. Such
testing in situ, however, will not be practicable for some MOVs within the
scope of Generic Letter 89-10. For those instances, the staff indicated in
the generic letter that alternatives to testing the MOV in situ may be
developed by the licensee or permit holder. The staff discussed several
possible alternatives at the workshops, including potential problems and
limitations associated with those alternatives, and various factors that
should be considered when a licensee or permit holder intends to use one of
those alternatives.
This generic letter supplement has been prepared to assist licensees and
permit holders in developing programs that will provide assurance of MOV
operability under design-basis conditions. Because the workshops were held
to answer specific questions on the generic letter, the supplement does not
contain all of the information necessary to develop and implement such
programs. Therefore, licensees and permit holders, together with the
Nuclear Management and Resources Council (NUMARC), should coordinate their
efforts in developing and implementing MOV programs. In this regard, NUMARC
is preparing guidelines for use by licensees and permit holders in
implementing the generic letter. NUMARC is also working with the Electric
Power Research Institute to establish a research program aimed, in part, at
determining the relationship between MOV performance characteristics. The
NRC staff will also provide the industry with additional information on MOV
operability as it becomes available.
9006070427
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Generic Letter 89-10 - 2 -
Supplement No. 1
Licensees and permit holders should review the entire package because the
staff guidance in the generic letter supplement should be considered in the
context of all questions and responses. This supplement has been approved
in accordance with NRC procedures for generic guidance and reflects the
current staff positions concerning the implementation of the generic letter.
Staff positions expanded, clarified, or modified following the workshops are
identified in the supplement. For example, the staff position on the scope
of the generic letter, provided in the response to Question 3, has been
modified with respect to dampers and other MOVs not located in piping
systems. In addition, as discussed in the response to Question 9, the
prevention of inadvertent MOV operation within the context of the generic
letter has been limited to the potential for MOV mispositioning from the
control room.
As a result of operating experience and research results, the NRC staff
determined that MOV tests beyond those acceptable in the past are necessary
to satisfy the NRC regulations. This determination constitutes backfitting.
Consequently, the staff guidance in Generic Letter 89-10 contains provisions
that were approved as backfits. Those provisions include MOV testing beyond
Section XI of the ASME Boiler and Pressure Vessel Code; consideration of the
operability of position-changeable MOVs located in safety-related systems;
testing of MOVs under design-basis conditions, where practicable, because of
uncertainties regarding industry sizing equations, and the extrapolation and
application of MOV test data; preparation or revision of procedures to
ensure correct MOV switch settings; and maintenance of records of test
methods, MOV failures, and corrective action (including trending). In
hindsight, the discussion in the generic letter should have referenced
10 CFR 50.109 and also should have stated that licensees and construction
permit holders were required to advise the NRC "if" the provisions of the
generic letter would be met. Nevertheless, the staff considers Generic
Letter 89-10 to be a backfit and prepared the generic letter in accordance
with NRC procedures for the issuance of staff guidance containing backfit
provisions.
Please direct questions or comments regarding this generic letter supplement
to the appropriate NRC project manager.
James G. Partlow
Associate Director for Projects
Office of Nuclear Reactor Regulation
Enclosure: As stated
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