ML20101S176

Responds to NRC Re Deviations Noted in Insp Repts 50-282/92-08 & 50-306/92-08 on 920414-0526.Corrective Actions:Normal Inservice Insp Program for Welds in High Energy Piping in Auxiliary Bldg Will Be Augmented

ML20101S176
Person / Time
Site:	Prairie Island
Issue date:	07/10/1992
From:	Eliason L NORTHERN STATES POWER CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
NUDOCS 9207170010
Download: ML20101S176 (4)

Text

,a Northem States Power Company 414 Nicollet Mall Minneapohs Minnesota 55401 1927 Telephone (612) 330-5500 July 10, 1992 10 CFR Part 2 Appendix C U S Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 205$5 PRAIRIE ISIAND NUCLEAR GENERATING PIANT Docket Nos. 50 282 License Nos. DPR-42 50 306 DPR-60 Reply to a Notice of Deviation NRC Inspection Report Nos. 282/92008 and 306/92008 Final Safety Analysis Report Commitment for

]nservice Examination of Hich Enerry Line Pioitig Pursuant to the provisions of 10 CFR Part 2, Appendix C, the following is submitted in response to the notice of deviation contained in your letter of i June 11, 1992.

Deviation During an NRC inspection conducted on April 14 through May 26, 1992, a deviation was identified from a commitment which you made in the Final Safety Analysis Report (FSAR). In accordance with the " General Statement )

of Policy and Procedure for NRC Enforcement Action", 10 CFR Part 2, i Appendix C (1992), the deviation is listed below:

I In Section I.2.3 of Appendix I to the FSAR, you committed to performing periodic inservice examination, in accordance with ASME Section XI for l Code Class II, Table ISC-261(b), Winter 1972 Addenda, to include 100 l

percent of the non encapsulated piping welds in feedwater and main steam ,

piping runs traversing the Auxiliary Building during each 10 year i inspection interval.

Contrary to the above, your inservico inspection (ISI) scope for this high I energy piping in the Auxiliary Building resulted in examination of only I approximately 25 percent of the total number of subject welds during each j 10 year inspection interval. '

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f4 rthern States Power Company USNitC July 10, 1992 Page 2 Final Safety Analysis Report. Annendix 7 Deviation Response Buckcround During the course of the investigation for the response to an allegation, AMS RI11-92-A 0027, a commitment was identified in the Final Safety Analysis Report, Appendix I, regaiding performance of inservice inspection of high energy piping welds in non-encapsulated piping runs traversing the Auxiliary Building beyond that required by the plant ASME Section XI program.

Specifically, Final Safety Analysis Report. Appendix 1, Section 1.2.3, lists several requirements to be satisfied when using encapsulation sleeves at design basis break locations as a means of reducing compartment pressurization levels in the event of a pipe break. For welds located outside of the sleeves, specific inspection requirements are included in the Final Safety Analysis Report. Appendix I states:

Piping welds which are not encapsulated and are in the piping runs trcversing the Auxiliary Building will be subjected to periodic in-service examination in accordance with the ASME Section XI Code Class II, Table ISC-261(b), Winter 1972 Addenda, except that the areas to be examined (as defined by the Code) shall include 100% of the welds within the inspeccion interval.

The final Safety Analysis Report, Appendix I, requires inspecting 100% of the total welds (as defined by the Code) during the inspection interval. This inspection scope is greater than that required by the ASME Section XI prograta 2 presently perforced at Prairie Island.  ;

keasont: for Deviation The basic cause of this deviation stems from an 6pparent overcight regarding inse rvice inspection requirements. Due to the length of time (over 15 years) since we initially failed to inspect these welds at the prescribed frequency, the reason for the oversight is not completely known. When the commitment was initially made, this was the only piping subject to ASME,Section XI, Inservice Inspection. Subsequent to the commitment, a Section XI program was fully implemented at Prairie Island. The subject piping has been considered in the program; i.e., our Section XI program contains inspections of Final Safety Analysis Report Augmented components (including these piping welds - even those which are not safety related and thus would not normally be included in a Section XI program). As discussed above, this inspection scope does not satisfy the Final Safety Analysis Report, Appendix 1 commitment. It is speculated that pe-sonnel responsible for the program at that time believed that the Section XI frequency requirements superseded those of the Final Safety Analysis Report commitment.

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f4 rthem States Power Company USNRC July.10, 1992 Page 3 Carrective Actions Taken and Results Aehleved Upon discovery of this oversight the following short term corrective actions were initiated:

1. A 10 CFR Part 50, Section 50.59 safety evaluation was prepared to address potential operability concerns regarding the consequences of high energy line breaks in the Auxiliary Building during such an event. This evaluation concluded that continued plant operation does not increase the potential. hazard to the health and safety of the public.

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2. A. review of previous inservice inspection results for the high energy piping welds was initiated. This review is now complete. No instances of

service induced indications were found during this review, substantiating the safety evaluation conclusion.

The following long term actions are currently in progress-l

1. During the two unit outage, scheduled for Fall, 1992, the normal Inservice Inspection prog;am for welds in high energy piping in.the Auxiliary Building will be augmented to include additional weld inspections in the main steam and feedwater lines. Selection of the welds for inspection will be based on stress levels calculated in the Plant Design Stress Analysis Reports. Those areas of highest stress, which are not encapsulated, will-be inspected.

2. Presuming favorable inspection results, the Updated Safety Analysis Report, Appendix I will be revised (during the next annual submittal) to reflect the current Inservice Inspection program.

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Corre1Alve Actions to Avoid Further Deviations This piping oncapsulation is a unique configuration. Conformance with the ISI program, which is reviewed by the NRC, is believed to be sufficient to ensure that piping is adequately inspected to ensure safe plant operation. Future commitments to au6alented inspections will be included in the ISI program.

Date When Corrective Actimis Will be Copag As noted above, the Updated Safety Analysis Report will be revised to correct this-discrepancy, dependent on obtaining favorable inspection results during thel upcoming Tall outage.

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l Northem State <, Power Company USNRC July 10, 1992 Page 4 j i

Please contact us if you have any questions related to this letter.

f^ ,

n R Eliason Vice President Nuclear Generation

. c: Regional ~ Administrator - Region III, NRC Senior _. Resident Incpector, NRC NRR Project Manager, NRC J E Silberg . ,

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