ML18052B040

Proposed Tech Specs,Removing or Replacing Snubbers Listed on Tables 3.20.1 & 3.20.2 W/Struts During Maint Outage Scheduled to Begin in Oct 1987

ML18052B040
Person / Time
Site:	Palisades
Issue date:	05/28/1987
From:	CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.)
To:
Shared Package
ML18052B039	List: ML18052B038 ML18052B040
References
NUDOCS 8706030357
Download: ML18052B040 (7)

Text

ATTACHMENT Consumers Power Company Palisades Plant Docket 50-255 PROPOSED TECHNICAL SPECIFICATION PAGE CHANGES May 28, 1987.

r--s-706030357 870528 l PDR P

ADOCK O5000255 m. I PDR LL_*

6 Pages TSP0587-0063~NL04

3.20 Shock Suppressors (Snubbers)

Applicability Applies to the operating status of the safety-r~lated piping shock suppressors (snubbers). The only sriubbers excluded from this requirement are those installed on nonsafety-related systems and then only if their failur*e or failure of the. system on which they are installed would have no adverse effect on any safety-related .system.

Objective To minimize the possibility of unrestrained pipe motion as might occur during an earthquake or severe transient.

Specifications 3.20.1 During all modes. of .operation except cold shutdown and refueling, all snubbers encompassed per Specification 3.20 shall be operable .except.

as noted below:

a. 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 4.16.1.c. on.the supported component or declare the sys~em inoperable.

Bases Snubbers are required to be operable to ensure that the sttuc.tural integrity.of the reactor coolant system and all other safety-related systems is maintained during and following a seismic or' other event initiating dynamic loads.

3-88 Proposed (next page is 3-92)

TSP0587-0063-NL04

4.16 Inservice Inspection Program for Shock Suppressors (Snubbers Applicability Applies to periodic surveillance of safety-related snubbers as described per Specification 3.20.

Specifications 4.16.1* Each snubber shall be demonstrated OPERABLE by performance of the following augmented inservice inspection program.

a.

• Visual Inspection Visual inspection shall be p~rformed in accordance with the following schedule:

No. Inqperable Snub be rs Subsequent ,Visu~l 1,2 per Inspection Period Inspection Period 0 18 months +/- 25%

1 12 months +/- .25%

2 6 months +/- 25%

3,4 124 days +/- 25%

5,6,7 62 days +/- 25%

8 or more 31 days +/- 25%

The snubbers may be categorized into.two groups: Those accessible and those'inaccessible during reactor operation. Each group may be inspected independently in accordance with the above schedule.

b. Visuai Inspection Acceptance Criteria Visual i~spections shall verify (1) that there ~re no visible indications of damage.or impaired OPERABILITY and .(2) attachments to the foundation or supporting structure are secure. Snubbers which appear inoperable as a result of .visual inspections may be determined OPERABLE for the purpose of establishing the next

_visual inspection interval, providing that (1) the cause of the rejection is clearly established and remedied for that particular snubber and for other snubbers that may be generically susceptible; and (2) the affected s_nubber is functionally. tested in the as-found condition and determined OPERABLE per Specifications 4.16.1.d or 4.16.1.3, as applicable. All snubbers connected to.an inoperable common hydraulic fluid reservoir shall be counted as inoperable snubbers.

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

2 The provisions of Specification 4.0.2 are not applicable.

4-71 Proposed TSP0587-0063-NL04

4.16.1 Specifications (continued)

c. Functional Tests At least once per 18 months during shutdown, a representative sample (10% of the total safety-related-snubber~ in use at the plant) shall be functionally tested either in place or in a bench test. The test shall verify the snubber has freedom of movement and is not frozen up. For each snubber which did not meet the functional. test acceptance criteria of Specification 4.16.1.d or 4.16.1.3, an additional 10% of the total shall be functionally j*

tested.

• The representative sample selected for functional testing shall include the various configurations, operating environments and the range of size and capacity of snubbers. Snubbers identified as especially difficult to remove or in high radiation zones during ~hutdown shall also be included in the representative sample.

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 resampling.

If any snubber ~elected 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 ~hall be independent of the requirements stated ~hove for snubbers not meeting the functional test acceptance criteria.

Snubbers of rated capacity greater than 50,000 pounds will be .

functionally tested in lots comprising 25% of their total during each refueling outage. In the event of one snubber failure out of the four tested, no additional snubbers will-be tested provided the problem is non-generic. *For each additional snubber failure, however, two additional snubbers will be tested until no further snubber failures are ident-ified .or all snubbers have been tested. Generic failures will be handled as the specific circumstance$ require.

3 Snubbers of rated capacity greater than 50,000 pounds are . not to be include d when defining the total number of safety-related snubbers in use at the plant.

4 Permanent or other exemptions from functional testing for individual snubbers I.

may be granted by the Commission only if a justifiable basis for exemption is presented and/or snubber life destructive testing was performed to qualify snubber operability for all design conditions at either the completion of their fabrication or at a subsequent date._

4-72 Proposed TSP0587-0063-NL04

4.16.l Specifications (continued)

For the snubber(s) found inoperable, an engineering evaluation shall performed on the components which are suppressed by the snubber(s). The purpose of this engineering evaluation shall be to determine if the components suppressed by the snubber(s) were adversely affected by the inoperability of the snubber(s) in order to ensure *that the suppressed component remains capable of meeting the designed service.

d. Hydraulic Snubbers Functional Test Acceptance Criter.ia The hydraulic snubber functional test shall verify that:

1. Activation (restraining action) is achieved within the specified range of velocity or acceleration in both *tension and compression. *

2. Snubber bleed, or release rate, where required, is within*the specified range in compression or tension. For. snubbers specifically required not to displace under continuous load, the ability of the snubber to withstand load without displacement shall be verified.

e. Mechanical Sriubbers Functional Test Ac~eptance Criteria The mechanical snubber functional test shall verify that:

. 1. The force that initiates free movement of the snubber rod in either tension or compression is less than the specified maximum drag force (break away friction).

2. Activation (restraining action) is achieved within the specified range of velocity or acceleration in both tension and compression.

3. Snubber release rate, where required, is ..within _the specified range in compression or tension. For snubbers s.pecifically required not to displace under continuous load, the ability of the snubber to withstand load without displacement shall be verified.

£. Snubber Service Life Monitoring A record of the service life of each snubber, the date at which the designated service* life commences and the installation and maintenance record_s on which the designated service life is based shall be ma~ntained as required by Specification 6.10.2.1.

Concurrent with the first inservice visual inspection and at least .once per 18 months thereafter, the installation and maintenance records for each safety related snubber in use in the plant shall be reviewed to verify that the indicated service lif_e 4-73 Proposed TSP0587-0063-NL04

4.16.1 f. (Continued)*

has not been exceeded or will not be exceeded prior to the next

-sch-edul-ed snubber life review. *If the indicated - service *rife will be exceeded prior to the next 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 re-evaluation, repla9ement or reconditioning shall be indicated in the records.

4.16 Bases The *visual inspection frequency is based upon maintaining a constant level of snubber protection to sistems. Therefore, the required*

inspection* interval varies inversely w1th the observed snubber _

failures and is determined by the number of inoperable snubbers found during an inspection. Inspections performed before that interval h.as 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 inspectioriinterval will override the previous schedul~.

when the cause of the rejection of a snubber is clearly established and remedied for the snubber and for any other snubbers that may be

~enerically 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 snubb.er by visual inspection, or are similarly ;Located or exposed to the .same environmental conditions such a~ temperature,. radiation and vibration.

When a 'snubber is . found inope_rable, an engineering evaluation is performed, iri addition to the determination of the snubber mode of*failur:e, in.order to determine i f any safety-related component or system has been adversely .affected by the inoperability of the snubber. The engineering evaluation shall determine whether or not t~e snubber.mode of failure has imparted a significant effect or degradation on the supported component or system.

Tei provide assurance of snubber functional reliability, a representative sample of the installed snubbers, *excluding snub be rs of rated capacity-greater than 50,000 pounds, will be functionally tested at 18 month intervals. A representative sample or snubbers of rated capacity greater than 50,000 pounds will b~ fun~tionally tested

.each refueling outage.

4-74 Proposed TSP0587-0063-NL04

4 .16 Bases (continued)

Hydraulic snubbers and mechanical snubbers may each be treated as a dif-ferent entity for the above surveillance programs.

The service life of a snubber is evaluated via manufacturer input and information through consideration of the snubber service conditions and assoc*iated installation and maintenance records (newly.

installed snubber, seal replaced, spring replaced, in high radiation area, in high-temperature area, etc * * * ). The requirement to monitor the snubber service life is included to ensure that the snubbers periodically undergo a performance evaluation in view of their age arid operating conditions. These records will provide statistical bases for future consideration of snubber service life.

The requirements for the maintenance of records and the snubber service life review are not intended to affect plant operation.

. 4-74a Proposed*

TSP0587-0063-NL04