ML20129G972

Requests Deferral of Core Shroud Reinspection Until Refueling Outage 18 (Currently Scheduled for Fall 1998)

ML20129G972
Person / Time
Site:	Cooper
Issue date:	10/22/1996
From:	Graham P NEBRASKA PUBLIC POWER DISTRICT
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
GL-94-03, GL-94-3, NLS960195, TAC-M94401, NUDOCS 9610300293
Download: ML20129G972 (4)

Text

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i e COOPER NUCLEAR STATION m- ,

P.O. BOX M, BROWNVLLE. NEBRAS (A 68321

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Nebraska Public Power District "T3fJ%""

NLS960195 October 22,1996 U.S. Nuclear Regulatory Commission Attention: Document Control Desk Washington, DC 20555-0001 Gentlemen:

Subject:

Reinspection of the Core Shroud Welds Cooper Nuclear Station, NRC Docket 50-298, DPR-46 l

References:

1. GL 94-03 dated July 25,1994,"Intergranular Stress Corrosion Cracking i of Core Shrouds In Boiling Water Reactors"

2. Letter to USNRC from G. R. Horn (NPPD) dated December 8,1995, "Results of Core Shroud Inspection"

3. GENE-523-174-1293, Revision 2," Evaluation and Screening Criteria for the Cooper Shroud" 1

4. Letter to G. R. Horn (NPPD) from D. L. Wigginton (USNRC) dated June 27,1996," Cooper Nuclear Station Core Shroud Inspection and Flaw Evaluation (TAC No. M94401)"

5. EPRI TR-105747 dated February 1996,"BWR Vessel and Internals ]

Project Guidelines for Reinspection of BWR Core Shrouds (BWRVIP- 1 l 07)"

6. Letter to USNRC from V. Wagoner, Technical Chairman BWRVIP f

l Integration Committee, dated July 17,1996," Clarifications to Core Shroud Reinspection Guidelines" The purpose of this letter is to request deferral of the Core Shroud reinspection until Refueling Outage 18 (currently scheduled for Fall 1998). During the 1995 refueling outage the Nebraska l Public Power District (District) completed the inspections required by NRC Generic Letter 94-03 (Reference 1). The results of the inspection were reported by the District in December 1995 (Reference 2). As stated in Reference 2, all evaluated welds meet the applicable Limit Load and/or Linear Elastic Fracture Mechanics (LEFM) screening criteria (Reference 3) and no furtber evaluation or non-destructive examination characterization is necessary. The NRC response (Reference 4) accepted our evaluation and concluded that plant operation could be continued for i

at least one 18-month fuel cycle. -

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.s NLS960195 October 22,1996 Page 2 of'2 The BWR Vessel and Internals Project (BWRVIP) submitted BWRVIP-07 in February 1996 (Reference 5) and provided additional information in July 1996 (Reference 6). Application of the guidance in these documents to Cooper Nuclear Station (Attachment A) indicates that the Core Shroud does not require reinspection for eight calendar years. We recognize that the NRC staff has not completed their review of the referenced BWRVIP documents. Therefore, the District is requesting a deferral of the Core Shroud reinspection for only one additional 18-month cycle. The District may, at a later date, request approval to extend the reinspection as allowed in Reference 5, or submit a plant-specific evaluation justifying a longer interval between inspections.

In order to effectively plan for the Spring 1997 refueling outage, the District requests NRC approval of this deferral by December 22,1996. l Should you have any questions concerning this matter, please contact me.

Sincerely, fDW P. D. Graham, Vice President - Nuclear

/dnm Attachments cc: Regional Administrator USNRC - Region IV Senior Project Manager USNRC - NRR Project Directorate IV-1 Senior Resident inspector USNRC NPG Distribution

Attachment I to NLS 960195 '

Page1of1 Cooper Nuclear Station NRC Docket No. 50-298 '_

License No. DPR-46 Attachment A L

The following table presents a summary of the 1995 core shroud inspection results at CNS in a format which allows determination of reinspection frequency as presented in Reference 5.

W eld Percentage Total Length of Percentage ofInspected Total Stress

• in BWRVIP-07 Allowed Number Inspected Circumferential Weld Length Containing Faulted Condition Reinspection Frequency (years)

Indications (in) Indications (ksi)  !

111 66.9 17.48 4.4 1.31 8 112 66.9 0 0 1.43 10  :

113 79.9 66.19 14.9 1.45 8 114 78.5 0 0 1.7 10 115 76.1 2.73 .6 2.5 8 II6A 73.4 2.14 .5 2.91 8 II6B 73.4 0 0 3.33 10 l

117 68.6 0 0 4.24 10

• Total stress calculated as the absolute sum of axial force and bending moment stresses.

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i ATTACHMENT 3 LIST OF NRC COMMITMENTS l

Correspondence No: NLS960195 l

l The following table identifies those actions committed to by the District in this l

document. Any other actions discussed in the submittal represent intended or  ;

i planned actions by the District. They are described to the NRC for the NRC's information and are not regulatory commitments. Please notify the Licensing Manager

! at Cooper Nuclear Station of any questions regarding this document or any associated l regulatory commitments.

COMMITTED DATE i COMMITMENT OR UUTAGE l

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l PROCEDURE NUMBER 0.42 l REVISION NUMBER 1.2 l PAGE 8 OF 10 l