B12543, Proposed Tech Specs 3.19 & 4.13 Re Snubber Testing & Surveillance

Proposed Tech Specs 3.19 & 4.13 Re Snubber Testing & Surveillance

ML20214R773
Person / Time
Site:	Haddam Neck File:Connecticut Yankee Atomic Power Co icon.png
Issue date:	06/01/1987
From:	Mroczka E CONNECTICUT YANKEE ATOMIC POWER CO.
To:
Shared Package
ML20214R759	List: B12543, Proposed Tech Specs 3.19 & 4.13 Re Snubber Testing & Surveillance ML20214R756
References
B12543, NUDOCS 8706080299
Download: ML20214R773 (6)

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Docket No. 50-213 B12543 f

Attachment 1 Haddam Neck Plant Proposed Revision to Technical Specifications Snubber Testing and Surveillance J -

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P ADOCK 05000213 PDR,

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3.19 Snubbers Applicability: This specification applies to snubbers which are attached to the reactor coolant system and all other safety-related systems whose structural integrity is needed to be maintained during and following a seismic or other event initiating dynamic loads.

Objective: To assure reactor coolant system and other safety related system motions are adequately restricted should a design basis earthquake or other transient occur.

Specification: A. During Modes 1, 2, 3, and 4 (Modes 5 and 6 for snubbers located on systems required operable in those Modes) all safety-related snubbers shall be maintained in an operable condition except as noted in 3.19.B and 3.19.C below. Snubbers on nonsafety-related systems shall be operable if their failure or failure of the system on which they are installed would have an adverse effect on any safety-related system.

B. With one or more snubbers inoperable, within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> replace or restore the inoperable snubber (s) to operable status and perform an engineering evaluation per Specification 4.13.c on the supported component or declare the supported system inoperable and follow the appropriate specification for that system.

Bases All snubbers are required to be operable to ensure that the structuralintegrity of the reactor coolant system and all other safety-related systems are maintained during and following a seismic or other event initiating dynamic loads. Snubbers excluded from this inspection program are those installed on nonsafety-related systems and then only if their failure, or failure of the system on which they are installed, would have no adverse effect on any safety-related system.

When a snubber is found inoperable, an engineering evaluation is performed, in addition to the determination of the snubber mode of failure, in order to determine if any safety-related component or system has been adversely affected by the inoperability of the snubber. The engineering evaluation shall determine whether or not the snubber mode of failure has imparted a significant effect or degradation on the supported component or system.

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4.13 Snubbers Applicability: This specification applies to the snubbers required to be

operable in accordance with Specification 3.19.

Objective: To provide assurance of snubber operability over the plant ,

service lifetime.

l Specification: Each snubber shall be demonstrated operable by performance of the following augmented inservice inspection program.

A. Visual Inspection Schedule All snubbers shall be visually inspected in accordance with the following schedule:

Number of Snubbers Found Inoperable During Inspection Next Required Or During Inspection Interval Inspection Interval * #

0 18 months + 25 %

1 12 months I 25%

2 6 months ! 25%

, 3, 4 124 days i 25 %

l 5, 6, 7 62 days 1 25 %

- 8 or more 31 days 1 25 %

4 The snubbers may be categorized into two groups:. those l

accessible, and those inaccessible during reactor operation.

Each group may be inspected independently in accordance with the above schedule.

• The inspection interval shall not be lengthened more than one step at a time.

1. The provisions of Specification 4.0.2 are not applicable.

B. Visual Inspection Acceptance Criteria Visual inspection shall verify (1) that there are no. visible indications of damage' or impaired operability, and (2) attachments to the foundation or supporting structure are -

secure. The inspection will also identify indications of -

, excessive leakage from hydraulic snubber reservoirs or

connections. Snubbers which appear inoperable as a result of i visual inspections may be determined operable for the purpose i

of establishing the next visual inspection interval, provided that l (1) the cause of the rejection is clearly established ' and

! remedied for that particular snubber and for other snubbers

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that may be generically ' susceptible, and (2) the affected snubber is functionally tested in the as-found condition and determined operable per Specifications 4.13.D or 4.13.E, as applicable.

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C. Functional Tests At least once per 18 months during shutdown, a representative sample of at least 10% of the total of each type of snubber in use in the plant shall be functionally tested either in place or in a bench test. For each snubber that does not meet.the functional test acceptance criteria of Specification 4.13.D or 4.13.E, an additional 5% of that type of snubber shall be functionally tested unti! no more failures are found or until all snubbers of that type have been functionally tested.

The representative sample selected for functional testing shall include the various configurations, operating environments and the range of size and capacity of snubbers. At least one (1) snubber shal1 be selected from each piping system containing snubbers. At least one (1) snubber shall be tested from the full range of snubber manufacturers and snubber sizes used. In the selection of the representative sample, consideration shall be given to other effects on snubbers such as vibration in the vicinity of equipment such as pumps, motors, turbines, valves, etc.

or fluid forces from a relief valve discharge.

Functional test samples shall be rotated such that different snubbers are tested at each test interval.

In addition to the regular sample, snubbers which failed the previous functional test shall be retested during the next test period. If a spare snubber has been installed in place of a failed snubber, then both the failed snubber (if it is repaired and installed in another position) and the spare snubber shall be retested. Test results.of these snubbers may not be included for the re-sampling.

If any snubber selected for functional testing either fails to lockup or fails to move, i.e., frozen in place, the cause will be evaluated and if caused by manufacturer or design deficiency, all snubbers of the same design subject to the same defect shall be functionally tested. This testing requirement shall be independent of the requirements stated above for snubbers not meeting the functional test acceptance criteria.

For the snubber (s) found inoperable, an engineering evaluation shall be performed on the components which are supported by the snubber (s). The purpose of this engineering evaluation shall be to determine if the 4-26B

components supported by the snubber (s) were adversely affected by the inoperability of the snubber (s) in order to ensure that the supported component remains capable of meeting the designed service requirement.

D. Hydraulic Snubbers Functional Test Acceptance Criteria The hydraulic snubber functional test shall verify that:

1. Activation (restraining action) is achieved within the specified range of velocity or acceleration in both i

tension and compression.

j 2. Snubber bleed, or release rate, where required, is j within the specified range in compression or tension.

! For snubbers specifically required not to displace

! under continuous load, the ability of the snubber to R withstand load without displacement shall be-verified.

1 E. Mechanical Snubbers Functional Test Acceptance Criteria i

l The mechanical snubber functional test shall verify that:

1. The force that initiates free movement of the

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j snubber rod in either tension or compression is less j than the specified maximum drag force.

1 4 2. Activation (restraining action) is achieved within the

! specified range of velocity or ace-leration in both j tension and compression.

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3. Snubber release rate, where required, is within the -

specified range in compression or tension. For i

snubbers specifically required not to displace under continuous load, the ability of the snubber .to withstand load without displacement shall be 1 verified.

i F. Snubber Service Life Monitoring i

, A record of the service life of each snubber, the date at

! which the designated service ' life commences -and the installation and maintenance records on' which the designated service life is based shall ~be maintained as

required by Specification 6.10.2.h.

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Concurrent with the first inservice visual inspection and at least once per 18 months thereafter, the installation l and maintenance records for each safety-related snubber .i j shall be reviewed to verify that the indicated service life o has not been exceeded or will not be exceeded prior to the l next scheduled snubber service life review. - If ' the

indicated service life will be exceeded prior to the next l 4-26C l

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,. . e scheduled snubber service life review, the snubber service life shall be reevaluated or the snubber shall be replaced or reconditioned so as to extend its service life beyond the date of the next scheduled service life review. This i reevaluation, replacement or reconditioning shall be indicated in the records.

I Bases The visual inspection frequency is based upon maintaining a constant level of snubber protection to systems. Therefore, the required inspection interval varies inversely with the observed snubber failures and is determined by the number of ,

inoperable snubbers found during an 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 less than 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 inservice 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 rejection of the snubber by visual inspection or are similarly located or exposed to the same environmental conditions, such as temperature, radiation, and vibration.

To provide assurance of snubber functional reliability, a representative sample of the installed snubbers will be functionally tested during plant shutdowns at 18-month intervals. These tests will include stroking of snubbers to verify freedom of movement over the full stroke, restraining characteristics, and drag force (if applicable). Ten percent (10%) of the total of each type of snubber represents an adequate sampling for these tests. Observed failures on these samples require testing of additional units.

Hydraulic snubbers and mechanical snubbers may each be treated as a different entity for the above surveillance program.

The service life is evaluated via manufacturer input and information with consideration of snubber service conditions and associated installation and maintenance records (newly installed snubber, seal replaced, spring replaced, in high radiation area, high temperature areas, location of potential fluid transient loading, etc.) The requirement to monitor the snubber service life is included to ensure that the snubbers periodically undergo a performance evaluation in view of age and operating conditions. (Due to implementation of the snubber service life monitoring program after several years of plant operation, the O Nrical records to date may be incomplete.) Snubber service life records will provide a statistical basis for future consideration of snubber service life.

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