ML20070F378

Application for Amend to License NPF-3,changing Tech Spec 4.7.7 Re Snubber Surveillance Requirements & 3/4.7.7 Re Snubbers Per Generic Ltr 90-09 on Snubber Visual Insp Intervals & Corrective Actions

ML20070F378
Person / Time
Site:	Davis Besse
Issue date:	03/01/1991
From:	Shelton D CENTERIOR ENERGY
To:
Shared Package
ML20070F375	List: ML20070F373 ML20070F378 ML20070F384
References
1904, GL-90-09, NUDOCS 9103080255
Download: ML20070F378 (7)

Text

,  ;

.i-Docket Numbar 50-346

., License Number NPP-3 Serial Numbar 1904.

. Enclosure-E '

Page 1

' APPLICATION FOR AMENDMENT TO  ;

FACILITY OPERATING LICENSE NUMBER-NPF-3 j DAVIS-BESSE NUCLEAR POVER STATION- -!

UNIT NUMBER 1

-1 Attached are the requested changes to the Davis-Besse Nuclear Power Station,

, Unit Number:1 Facility Operating License Number NPF-3. Also included is the.

. Safety Assessment and_Significant_ Hazards Consideratlon.

The proposed changes (submitted under cover letter Serial Number 1904) concern:- 4 Technica1' Specifications Section 3/4.7.7, snubbers Technical Specifications Bases 3/4.7.7, Snubbers By: ND '

D. C. Shelton, Vice President, i Nuclear - Davis-Besse l 3

Sworn and subscribed before me this lat day of March,1991.

I k<abh3 LL

'I Notary Public6 State of Ohio _

EVELYNLDRESS- :i ununmauc.snuoFoHO- ,

40mmedutgesM41#4 9103080255 DR 9103o1 p ADOCK 05000346 PDR I

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• Docket Number 50-346 License Number NPF-3 Serial Number 1904

, Enclosure Page 2 The following information_is provided to support issuance of the requested change to the Davis-Besse Nuclear Power Station, Unit Number 1 Operating i License Number NPF-3, Appendix A, Technical Specifications 4.7.7 and Bases 3/4.7.7.

A. Time Required to Implement: This change is to be implemented within 45 days after the NRC issuance of the License Amendment.

.B. Reason for Change (License Amendment. Request Number 91-0001): Replace the current snubber visual inspection interval schedule with the schedule recommended by NRC GL 90-09.

C. Sai~ety Assessment and Significant Hazards Consideration: See Attachment 1.

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.. Dockot Hush;r 50-346 Liccasa Numbar NPF-3 Sarici Number 1904

. Attachment Page 1 SAFETY ASSESSMENT AND SIGNIFICANT HAZARDS CONSIDERATION FOR LICENSE AMENDHENT REQUEST NUMBER 91-0001 TITLEt License Amendment Request (LAR) to revise the Snubber Visual Inspection Program, Technical Specification 4.7.7.

DESf1 I PTION:

The purpose of this proposed change is to modify the Davis-Besse Nuclear Power Station (DBNPS) Operating License NPF-3, Appendix A, Technical Specifications (TS). Attached are the proposed mark-up changes to the TS's.

The proposed changes affect TS 4.7.7 (Snubbers Surveillance Requirements) and TS Bases 3/4.7.7 (Snubbers) by incorporating changes to the TS snubber visual inspection interval schedule as recommended by the Nuclear Regulatory Commission (NRC) in Generic Letter 90-09, Alternative Requirements for Snubber Visual Inspection Intervals and Corrective Actions, dated December 11, 1990 (Toledo Edison letter Log Number 3376).

This LAR proposes replacing the snubber visual inspection interval schedule of TS 4.7.7.lb with the schedule recommended by NRC Generic Letter 90-09.

Other revisions to the TS and Bases have been proposed to provide consistency between the current DBNPS TS's and the revised schodulo.

The proposed changes specify a schedulo for snubber visual inspections that is based on the number of inoperable snubbers found during the previous visual inspection, the total population or group size for each snubber type, and the previous inspection interval. Snubbers may be grouped by Toledo Edison (TE) based upon physical characteristics and their accessibility during power operation (accessible or inaccessible). Groups may be inspected independently or jointly. However, whether to inspect groups independently or jointly must be determined by TE and documented before any inspection, and that decision must be used as the basis upon which the next inspection interval is determined for that group.

New TS Table 4.7-5 is proposed to replace the existing requirements of TS 4.7.7.lb for determining the next visual inspection interval. Table 4.7-5 establishes three limits for determining the next visual inspection interval corresponding to the population or group size for a given type of snubber.

The next visual inspection interval may be twice, the same, or reduced by as much as one-third of the previous inspection interval. This interval depends on the number of unacceptable snubbers found in proportion to the size of the population or group for each type of snubber included in the 1

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... Docket Numbar 50-346

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Licensa Number NPF .3 Serial NumberJ1904- .

. " Attachment-4 Page 2-previous l inspection.- Por a population or group that differs from the representative size provided, the values for the limits may be found by .

interpolation from the limits provided in Table 4.7-5 for determining-the

.next inspection interval. Footnotes to. Table 4.7-5 provide further guidance on interpolation, determining inspection intervals _and the applicability of TS 4.0.2-(extending surveillance intervals) consistent with the guidance provided in Generic Letter 90-09.

• Use of the vording " sample criteria" is proposed to be deleted from TS 4.7.7.lb since 100 percent of the snubbers are inspected during each visual inspection and there is no varying sample' criteria (e.g., changing sample size based on the number of failures is not used).

A new paragraph is proposed to be added to TS 4.7.7.lb, as-recommended by Generic Letter 90-09, which discusses the use of Table 4.7-5 in determining inspection intervals, inspection of groups independently from each other, and. commencement of the start of the first inspection interval.

The term " group" has been substituted for the term " category" (contained in

- Generic letter 90-09) throughout the proposed Table 4.7-5 to provide cousistency.vith the present DBNPS TS nomenclature. In addition, footnote six of Table 4.7-5 has been modified from that in Generic. Letter 90-09 to incorporate the vording of_ existing footnote five of TS 4.7.7.lb, regarding the deferring of inspections of inaccessible snubbers due to plant

-conditions.

A snubber would be considered unacceptable if it falls to satisfy the '

acceptance criteria of the visual inspection. The snubber visual inspection acceptance criteria of TS '.7.7.lc, is not proposed to be revised by these changes.

3 The response to failures,_under TS 4.7.7.1d, for snubbers which do not meet

.the-visual inspection acceptance criteria of TS 4.7.7.le is proposed to be revised only for clarity and consistency with the other proposed changes.

. The intent of'the revised wording is consistent with the current TS requirements and with-the proposed-schedule.

TS 4.7.7.2b, Functional Test Program - Inspection Interval and Sample Criteria, is proposed to be revised to provide nomenclature consistent with the-proposed revisions to the Surveillance Requirements of TS 4.7.7.lb.

Accordingly, under the-Functional Test Program, the snubbers-vill continue to be categorized.into groups based on physical characteristics and accessibility.

The-description of the visual inspection program in the Bases 3/4.7.7,.

Snubbers, is proposed for revision consistent-vith the proposed inspection schedule.

Several administrative and typographical corrections are also included in this proposed change. The word " ACTION" in footnote one to TS 3.7.7 ACTION a should be in all capital letters as this is a defined term. The asterisked' footnote to TS 4.7.7.2 dealing with functional testing during

. Dockot Numbar 50-346 Licensa Numbar NPF-3 Serial Numbar 1904

, Attachment Page 3 Cycle 6 operation is proposed for deletion as it is no longer applienble.

The vord " snubber" in line two of TS 4.7.7.2a should be plural and the vord

" systems" should be added to read "non-safety related systems" in line six of Bases 3/4.7.7.

SYSTEMS, COHp0NENTS AND ACTIVITIES AFFECTED:

The activity affected by these proposed changes is the Visual Inspection Program schedule for hydraulic and mechanical snubbers. These changes do not make hardvare changes.

SAFETY FUNCTIONS OF THE AFFECTED SYSTEMS, COHp0NENTS AND ACTIVITIES The function of the Visual Inspection Program Schedule is to require on a predetermined periodic basis the observation of the condition of installed snubbers to identify those that are damaged, degraded, or inoperable as caused by physical means, leakage, corrosion or environmental exposure.

This inspection complements the Functional Testing Program (which is a separate process) in ensuring snubber operability.

EFFECTS ON SAFETY Snubbers ensure that the structural integrity of the reactor coolant system and other safety-related systems is maintained during and following a dynamic event. Snubbers, or dynamic restraints, are used to restrain piping or equipment during dynamic events or transient loads, while allowing relatively unrestrained movement of the piping / component during normal heatup or cooldown operations.

Technical Specifications (TS) impose surveillance requirements for visual inspection and functional testing of safety-related snubbers. Verification that a snubber can operate within specific performance limits is assured through performance of the Functional Testing Program of TS 4.7.7.2.

Functional testing provides a high confidence level that the snubbers vill operate within the specified acceptance limits. The performance of visual examinations is a separate process that complements the functional testing program in ensuring snubber operability.

The current TS specify a schedule for snuhber visual inspection that is based on the number of inoperable snubbers found during the previous visual inspection. Because the current schedule for snubber visual inspection in TS 4.7.7.lb is based on only the number of inoperable snubners found during the previous visual inspection, irrespective of the size of the snubber population or group, the visual inspection schedule can be excessively restrictive requiring inspections as frequently as once every 31 days.

Subsequently, plant personnel may be subjected to unnecessary radiological exposure to comply with the visual examination requirements.

u Docket Numbar 50-346

. , '- License Numbet NPF-3 Serial Number 1904 Attachment-Page 4-.

.To alleviate this situation,.the NRC Staff developed an alternate Schedule for visual inspections. In Generic Letter 90-09, the NRC Staff provides-that:this schedule establishes an acceptable visual inspection confidence for snubber operability for nuclear power stations. Furthermore, this alternate schedule. generally allovs for the performance of visual inspections and corrective actions during plant outages which should reduce associated potential. radiological exposures.

This alternate schedule, proposed as Table 4.7-5, for determining the next interval for the visual inspection of snubbers is based upon the number of unacceptable snubbers found during the previous inspection, the total population or group size for each snubber type, and the previous inspection interval. The requirements for functional testing snubbers under TS 4.7.7.2-are not affected by these proposed changes and, therefore, the associated confidence is not affected.

The proposed changes to the visual inspection schedu'e of the DBNpS TS are consistent with those developed by the NRC and presented in Generic Letter 90-09 as pro,iding an acceptable visual inspection confidence in snubber operability. Accordingly, the proposed _ changes do not adversely affeet the identification of damaged, degraded, or inoperable snubbers as caused by

. physical-means, leakage, corrosion or environmental exposure.

SIGNIFICANT HAZARDS CONSIDERATION The Nuclear Regulatory Commission has provided standards in 10 CFR 50.92(c)

-for determining whether a significant hazard exists due to a proposed amendment to an Operating License for a facility. A proposed amendment involves no significant hazards consideration if operation of the facility in accordance with the proposed changes voulds (1) Not involve a significant increase in the probability or consequences of an accident previously evaluated (2).Not create the possibility of a new or different kind of accident from any accident previously evaluated; or (3) Not involve a significant reduction in a margin of safety.- Toledo Edison has reviewed 3 the proposed change and determined that a-significant hazards consideration does not exist because operation of - the Davis-Besse Nuclear Power Station, Unit Number 1, in accordance with these changes vould la. Not involve a significant increase in the probability of an accident

, previously evaluated because no initiators or assumptions for a i previously evaluated accident are afIceted by these proposed changes-L to Technical Specification 4.7.7 and Bases 3/4.7.7. There are no '

L hardware or operational modifications assoelated with these changes.

l The proposed changes are consistent with those developed by the NRC

-and recommended in Generic Letter 90.-09 for ensuring snubber operability.

l 1, ib. Not involve a significant increase in the consequences of an accident previously evaluated because no initiators or assumptions for a previously evaluated accident are affected by these proposed changes to Technical Specification 4.7.7 and Bases 3/4.7.7. There are no hardware or operational modifications associated with these changes.

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. Docket Numbor 50-346-License Number NPF-3 Serial Number 1904 Attachment

. Page 5 2a. Not erente the possibility of a new kind of accident from any accident previously evaluated because no new accident initiators are created. No new hardware changes are being made and no new operating manipulations are being created by these proposed changes to Technical Specification 3/4.7.7 and Bases 3/4.7.7.

2b. Not create the porsibility of a different kind of accident from any accident previously evaluated because no accident initiators are created. No changes in hardware or plant manipulations are being created by these proposed changes to Technical Specification 4.7.7 and Base 3/4.7.7.

3. Not involve a significant reduction in a margin of safety because the proposed changes are consistent with those developed and approved by the NRC to ensure the revised schedule for visual inspections maintains the same confidence level in snubber operability as the existing schedule. Since the snubber Functional Test Program (which provides a high confidence level of snubber operability) is not being changed, and since there is no reduction in the NRC accepted licensing basis, there is no significant reduction in the margin of safety.

CONCLUSION On the basis of the above, Toledo Edison has determined that-the License Amendment Request does not involve a significant hazards consideration. As this License Amendment Request concerns a proposed change to the Technical Specifications that must be reviewed by the Nuclear Regulatory Commission, this License Amendment Request does not constitute an unreviewed safety question.

ATTACilHENT Attached are the proposed marked-up changes to the Operating License.

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