ML20071P448

TS Change Request 93-31 to Licenses DPR-44 & DPR-56,deleting Footnote in TS Re Snubber Functional Testing Frequency & Making Permanent,Current One Time Snubber Functional Test Frequency of 24 Months

ML20071P448
Person / Time
Site:	Peach Bottom
Issue date:	08/03/1994
From:	Hunger G PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
Shared Package
ML20071P450	List: ML20071P448 ML20071P461
References
NUDOCS 9408090329
Download: ML20071P448 (7)

Text

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eeco c"e ov cema>"v PECO ENERGY Nuclear Group Headauarters 965 Chesterbrook Boulevard Wayne. FA 19087-5691 August 3,1994 Docket Nos. 50-277 50-278 Ucense Nos. DPR-44 DPR-56 j U. S. Nuclear Regulatory Commission Attn: Document Control Center Washington, DC 20555 I

Subject:

Peach Bottom Atomic Power Station, Units 2 and 3 Technical Specification Change Request 93-31 j

Dear Sir:

1 PECO Energy Company (PECO Energy) hereby submits Technical Specifications Change Request (TSCR) No. 93-31, in accordance with 10 CFR 50.90, requesting a change to Appendix A of the Peach Bottom Facility Operating Ucenses. The proposed changes would delete a footnote in the Technical Specifications regarding snubber functional testing frequency, and make permanent the current one time snubber functional test frequency of 24 months.

Attachment 1 to this letter describes the proposed changes, and provides justification for the changes. Attachment 2 contains the marked-up Technical Specification pages.

If you have any questions regarding this matter, please contact us.

Very truly yours,

%.c. % y G. A. Hunger, Jr.

Director - Ucensing

Enclosures:

Affidavit, Attachment 1, Attachment 2 ,

I cc: T. T. Martin, Administrator, Region I, USNRC '

W. L. Schmidt, Senior Resident inspector, PBAPS W. P. Dornsife, Commonwealth of Pennsylvania

r. c i tvt 940809o329 94o803 PDR P ADOCK 05000277 hh, i PDR

COMMONWEALTH OF PENNSYLVANIA :

ss.

COUNTY OF CHESTER  :

W. M. Smith, Ill, being first duly sworn, deposes and says:

That he is Vice President of PECO Energy Company; the Applicant herein; that he has read the attached Technical Specifications Change Request (Number 93-31) for Peach Bottorn Facility Operating Licenses DPR-44 and DPR-56, and knows the contents thereof; and that the statements and matters set forth therein are true and correct to the best of his knowledge, information and belief.

AJ Vice President Subscribed and s orn to before me this # day of M 1994. 1 ks,i ot!ry Public mm u2TJe;;h.Ls

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ATTACHMENT 1 PEACH BOTTOM ATOMIC POWER STATION UNITS 2 AND 3 Docket Nos. 50-277 50-278 License Nos. DPR-44 DPR-56 TECHNICAL SPECIFICATION CHANGE REQUEST 93-31

" Permanent Snubber Functional Surveillance Test Period of 24 Months" Supporting Information for Changes 4 Pages

t Docket Nos. 50-277 ,

50-278 Ucense Nos. DPR-44 DPR-56 PECO Energy Company (PECO Energy), Ucensee under Facility Operating Ucenses '

DPR-44 and DPR 56 for the Peach Bottom Atomic Power Station (PBAPS) Unit No. 2  !

and Unit No. 3, respectively, requests that the Technical Specifications contained in Appendix A to the Operating Ucenses be amended. Proposed changes to the Technical Specifications are indicated by a hand written mark-up of page 234b. The proposed revised page for each unit is included in Attachment 2.

Introduction As part of PECO Energy's change to a 24 month fuel cycle, a Technical Specification  !

Change Request (TSCR) to extend the period of testing of snubbers from 18 months .

(22.5 months with grace) to 24 months (30 months with grace) was submitted to the i Nuclear Regulatory Commission (NRC) in a letter, dated September 28,1992. ,

Additional information regarding the snubber surveillance period was provided by '

PECO Energy in a letter dated July 7,1993. The NRC allowed for a one time change

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to the snubber testing period by including a footnote to TS page 234b, in their SER dated August 2,1993. The NRC stated:

....that recent surveillance test results yielded snubbers that failed .

the ST acceptance test criteria, but which the licensee had evaluated through further analysis to be operable. The licensee does repair or ,

replace any snubber that has failed the ST acceptance criteria. The staff will further review the licensee's snubber program concerning the characterization of snubbers that fail ST criteria prior to approving  ;

this TS change for all cycles beyond the one time approval granted in ,

this amendment...... Based on snubber surveillance history which, despite  ;

incidence of failed snubbers, has not resulted in the inoperability of  !

attached piping, and on the additional sample requirements of TS  ;

4.11.D.5, and on the licensee's snubber program that repairs or replaces  :

snubbers that fail ST criteria, the staff concludes that the licensee's l proposed change to a 24 month refueling cycle is acceptable on a one  !

time basis..." .

i The purpose of this TSCR is to make the one time change a permanent change.  !

Descriotion of Chances The specific changes are included in a markup of page 234b attached to this  !

submittal. This change concerns the elimination of the footnote on page 234b for both Units 2 and 3.

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Docket Nos. 50-277 50-278 Ucense Nos. DPR-44 DPR-56 Safgtv Discussion Changing the inspection cycle to 24 months (maximum of 30 months with grace) will not reduce the ability of the functional testing program to confirm the operability of the snubber population. The original interval of 18 months was selected to accommodate the need to test snubbers that were inaccessible during operation. The sample size of 10 percent appears to be arbitrarily selected as evidenced by a lack of supporting information.

Past functional surveillance test results have not indicated any failure mechanism that would be more severe given an additional service interval between functional tests. A historical search (in accordance with the requirements of Generic Letter 91-04,

" Changes in Technical Specification Surveillance Intervals to Accommodate a 24 Month Fuel Cycle") of the snubber functional ST at PBAPS was conducted back to 1982. This search identified some snubbers that did not meet the initial functional test criteria. These criteria are a screen that the station uses to determine if additional engineering analysis is required to determine the operability of the snubber. For all those snubbers found to not meet these screening criteria, an engineering analysis was performed. In all cases the engineering analysis revealed that the piping system was operable. However, each of the snubbers that did not meet the screening criteria was either reconditioned or replaced.

A TS Service Life monitoring program prevents snubbers from remaining in service past their recommended life. If a snubber's service life would expire prior to the next scheduled review (i.e., refueling outage) then the snubber is reconditioned, replaced or reevaluated to extend its service life. Snubbers do not require preventative maintenance, except for seals on hydraulic snubbers which are replaced as part of the service life monitoring program. The seals of all hydraulic snubbers which would exceed their recommended life during the next cycle are either replaced or reconditioned.

Lastly, ASME OM Code 1990, ANSI Standard B31.1 or ASME Section XI does not require a 100 percent functional test of the snubbers over a 15 year cycle (i.e.,10 percent every 18 months yielding 100 percent review every 15 years.) In addition, NRC accepted surveillance schemes do not satisfy this 100 percent review every 15 year criterion. Several facilities have well in excess of 370 hydraulic snubbers, and in accordance with their TS approved plans (i.e., test 37 snubbers per sample with no failures) these plants would require more than 15 years to test 100% of the snubbers.

Further, because of the their location and size, certain snubbers are tested on a more frequent basis to meet the selection criteria of TS 4.11.D.4b (i.e., a representative sample.)

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Docke.t Nos. 50-277 50-278 License Nos. DPR-44 .

DPR-56  ;

information Sucoortina a Finding of No Significant Hazards Consideration The change request proposed in this Application does not constitute a significant hazards consideration in that:

l} The orocosed chance does not involve a significant increase in the orobability or consecuences of an accident oreviously evaluated. because the probability  !

of a seismic or other dynamic event is independent of the surveillance period for snubber tests. The change does not introduce any failure mechanisms to l the previously considered events. The consequences of an accident previously i evaluated in the SAR is not increased by the proposed revision to he snubber l TS. No physical changes are being made to the plant. The snubbers' role in mitigating the consequences of an accident is to provide restraint during seismic or other dynamic events while permitting the slow movement of piping and components during heatup and cooldown. The proposed TS change will  !

not affect the snubbers ability to continue to perform this role for the following reasons: 1) Changing the inspection cycle to 24 months will not reduce the ability of the functional testing to confirm the operability of the snubber population. The original interval of 18 months was selected to accommodate the need to test snubbers that were inaccessible during normal operation.

Since snubbers do not require preventative maintenance during the operating cycle, the additional time added by a 24 month operating cycle has minimal impact, if any, on snubber operability. 2) The requirement to monitor service life remains part of TS. The review of snubber service life records is a j documentation review of the snubbers service life. If a snubber's service life would expire prior to the next scheduled review then the snubber is reconditioned, replaced or reevaluated to extended its service life. 3) Snubber i functionel testing has shown no failure mechanism which would be aggravated l by an extension of the test interval to 24 months. A historical search of )

completed snubber functional STs was completed. The historical search  ;

indicated that even though the snubbers did not always meet the initial screening functional test criteria of the ST, the piping system was operable ,

based on an engineering evaluation and there was no evidence of a time ,

dependent failure mechanism. To ensure the snubber remains operational i during the next operating cycle, snubbers not meeting the screening ST acceptance criteria are either replaced or reconditioned.  !

ii) The orocosed change does not create the oossibility of a new or different kind of accident from any orevioustv evaluated because the proposed change does not involve operational procedure or physical changes to the plant. Since snubbers will continue to meet their design basis of protecting the piping and equipment during dynamic events, the possibility of a different type of accident will not be created. ,

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Docket Nos. 50-277 50-278 Ucense Nos. DPR-44 DPR-56 iii) The orocosed change does not involve a significant reduction in a margin of safety, Tnere may be a slight increase, if any, in the possibility of undetected snubber failures because of the increase in the interval of functional testing for snubbers; however, the historical data of previous snubber functional surveillance testing and the supporting engineering evaluations indicate that on those occasions where snubbers did not meet initial surveillance testing requirements, the piping systems were all operable. Therefore, the probability of occurrence of a malfunction of equipment is minimal and equipment important to safety (ITS) that use snubbers will continue to meet design requirements and the margin of safety will be unaffected.

Environmental Assessment An environmental impact assessment is not required for the changes proposed by this Application because the changes conform to the criteria for " actions eligible for categorical exclusion" as specified in 10 CFR 51.22(c)(9).

Conclusion The Plant Operations Review Committee and the Nuclear Review Board have reviewed these proposed changes and have concluded that they do not involve an unreviewed safety question and are not a threat to the health and safety of the public.

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