Program for periodic testing of MOVs per Generic Letter 89-10
Conference
·
OSTI ID:122576
- TU Electric, Glen Rose, TX (United States). Comanche Peak Steam Electric Station
Generic Letter 89-10 issued by the United States Nuclear Regulatory Commission recommends periodic verifications of the capabilities of motor operated valves (MOVs) to perform their design basis functions. At TU Electric`s Comanche Peak nuclear power plant, the present MOV verification methodology requires diagnostic testing wherein operational readiness is demonstrated by satisfying test procedure acceptance criteria. The test procedure acceptance criteria account for differences in MOV performance between ``static`` and ``design basis differential pressure`` conditions, and provide margin for reasonably anticipated increases in ``valve factors`` over the valve`s service life. Consequently, it is sufficient to perform testing under static conditions to periodically verify continued MOV operational readiness under design basis differential pressure (DP) conditions. TU Electric has determined that intervals varying from two to six refueling cycles (three to nine years) are appropriate between verification tests. The maximum duration between verification tests is a function of: (1) the relative importance of each MOV to plant safety, (2) each MOV`s design margin, and (3) the maximum duration between maintenance activities which require subsequent static verification testing. In some cases, the implemented switch settings may necessitate a duration between static verification tests less than the maximum duration justified by engineering. This paper describes how the TU Electric program addresses this long term aspect of GL 89-10. Present and future plans are presented and discussed.
- OSTI ID:
- 122576
- Report Number(s):
- CONF-950740--; ISBN 0-7918-1349-5
- Country of Publication:
- United States
- Language:
- English
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