ML19308B009
| ML19308B009 | |
| Person / Time | |
|---|---|
| Site: | Oconee  |
| Issue date: | 11/30/1976 |
| From: | NRC COMMISSION (OCM) |
| To: | |
| Shared Package | |
| ML19308B004 | List: |
| References | |
| NUDOCS 7912120767 | |
| Download: ML19308B009 (1) | |
Text
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O NRC STAFF GUIDELINES FOR EXCLUDDlG EXERCISING (CYCLING) TESTS OF CERTAIN VALVES OURING PLANT OPERATION Any valve which when exercised (cycled) could put the plant in an unsafe condition should not be tested. Below are some examples of the types of valves that should be specifically excluded from exercising (cycling) tests during plant operation *:
1.
All valves whose failure in a non-conservative position during the cycling test would cause a loss of system function should not be exercised. Valves in this category would typically include all non-redundant valves in lines such as a single discharge line from the refueling water storage tank, or >ccunulator discharge lines in PWR's and the HPCI turbine steam supply a'.a the HPCI pump discharge in BWR's. Other valves may fall into this category under certain system configurations or plant operating modes. For example, when one train of a redundant system such as ECCS is inoperable, non-redundant valves in the remaining train should not be cycled since their failure would cause a loss of total system function.
2.
All valves, whose failure to close during a cycling test would result in a loss of containment integrity. Valves in this category would typically include all valves in containment penetrations where the redundant valve is open and inoperable.
3.
All valves, which when cycled, 'could subject a system to pressures in excess of their design pressures.
It is assumed for the purpose of a cycling test, that one or more of the upstream check valves has failed unless positive methods are available for detennining the pressure or lack thereof on the high pressure side of the valve to be cycled. Yalves in this category would typically include the isolation valves of the residual heat removal /
shutdown cooling system and, in some cases certain ECCS valves.
- All ASME Section XI Category A and B valves should be cycled, as practicable, at each cold shutdown, but need not be cycled more often than once every 3 months.
T M 2120'767
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