ML20107L061
| ML20107L061 | |
| Person / Time | |
|---|---|
| Site: | Vermont Yankee File:NorthStar Vermont Yankee icon.png |
| Issue date: | 11/06/1984 |
| From: | VERMONT YANKEE NUCLEAR POWER CORP. |
| To: | |
| Shared Package | |
| ML20107L047 | List: |
| References | |
| NUDOCS 8411130396 | |
| Download: ML20107L061 (1) | |
Text
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J-3 j' S qa Y~ .t VYNPS 2 ;
3.6.I and 4.6.I SHOCK SUPPRESSORS (SEUBBERS) l f All snubbees.are required operable to ensure that the structural integrity of the Reactor Ccclant System and all other.
i .cafety-related systems is maintained during and following a seismic or other event initiating dynamic loads.
!, The visual, inspection frequency is based upon maintaining a constant level.of snubber protection to systems.
I Therefore the required inspection interval varies inversely with the observed snubber. failures.and is determined by. !
f- f -the number'of inoperable snubbers found during an inspection. Inspections performed before that' interval has elapsed.
i j may be used as a new reference point to' determine the next inspection. However, the results of such early inspections F 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.. j i ~
' When the cause of the rejection of,a snubber is. clearly established and remedied for that snubber and for any other i 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 (1) of a specific make or model,
' (2) of the same design, and (3) similarly located or exposed to the same environmental conditions such as temperature,
! radiation, and vibration. These characteristics of the snubber installation shall be evaluated to determine if
! further functional testing of similar snubber installations is warranted.
l When a snubber is found inoperable, an engineering evaluation is performed, in addition to the determination of the j anubber mode of failure, in order to determine.if-any safety-related component or system has been adversely affected j by the inoperability of the snubber. -The engineering evaluation shall determine whether or not the snubber mode of l
failure has imparted a significant effect or degradation on the supported component or system. ,
l To provide assurance of snubber functional reliability, a representative sample of the installed snubbers will be
- functionally tested once each operating cycle. Observed failures of these sample snubbers shall require functional j testing of additional units.
l 3.6.J THERMAL HYDRAULIC STABILITY j l
tot allowing operation in a natural circulation mode will provide additional stability margin, and it will provide l
protection against a reactivity insertion transient due to starting of an idle recirculation pump from the natural
- circulation mode.
i i Amendment No. 2A, 39 125
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