ML20095C823
| ML20095C823 | |
| Person / Time | |
|---|---|
| Site: | Cooper  |
| Issue date: | 12/07/1995 |
| From: | NRC (Affiliation Not Assigned) |
| To: | |
| Shared Package | |
| ML20095C826 | List: |
| References | |
| NUDOCS 9512120272 | |
| Download: ML20095C823 (1) | |
Text
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BASES:
3.6.H and 4.6.H Snubbers Snubbers are designed to ptevent unrestrained pipe motion under dynamic loads as might eccur during an earthquake or severe transient, while allowing normal thermal motion during STARTUP and SHUTDOWN. The consequence of an inoperable snubber is an increase in l the probability of structural damage to piping as a result of a seismic or other event initiating dynamic loads. It is therefore required that all snubbers required to protect the primary coolant system or any other safety system or component be OPERABLE during REACTOR POWER OPERATION.
Because the snubber protection is required only during relatively low probability events, o period of 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> is allowed for repairs or replacement.
Since plant STARTUP should not commence with knowingly defective safety related equipment, Specification 3.6.H.3 prohibits STARTUP with inoperable snubbers.
All safety related snubbers are visually inspected for overall integrity and OPERABILITY. l The inspection frequency is based upon maintaining a constant level of snubber protection.
Thus the required inspection interval varies inversely with the observed snubber failures.
The number cf inoperable snubbers found during a required inspection determines the time interval for the next required inspection.
Inspections performed before that interval has elapsed may be used as a new reference point to determine the next inspection.
However, the results of such early inspections performed before the original required time interval has elapsed (nominal time less 25%) may not be used to lengthen the required inspection interval. Any inspection whose results require a shorter inspection interval will override the previous schedule.
When the cause of the rejection of a snubber is clearly established and remedied for that snubber and for any other snubbers that may be generically susceptible, and verified by functional testing, that snubber may be exempted from being counted as inoperable.
Generically susceptible snubbers are those which are of a specific make or model and have the same design features directly related to rej ection of the snubber by visual inspection, or are similarly located or exposed to the same environmental conditions, such 4
as temperature, radiation and vibration.
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9512120272 951207 PDR ADOCK 05000298 P
PDR Amendment No. S';,148,173
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