ML17328A572

Application for Amend to License DPR-58,extending Visual Insp Interval for Inaccessible Snubbers as Delineated in Tech Spec 3/4.7.8 from 900911 Until Unit 1 Refueling Outage, Scheduled for 901012

ML17328A572
Person / Time
Site:	Cook
Issue date:	02/09/1990
From:	Alexich M INDIANA MICHIGAN POWER CO. (FORMERLY INDIANA & MICHIG
To:	Murley T NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
Shared Package
ML17328A573	List: ML17328A572 ML17328A574
References
AEP:NRC:1114, NUDOCS 9002220692
Download: ML17328A572 (7)

Text

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ACCESSION NBR:9002220692 DOC.DATE: 90/02/09 NOTARIZED: NO DOCKET I FACIL:50-315 Donald C. Cook Nuclear Power Plant, Unit 1, Indiana a 05000315 AUTH'AME r. j'UTHOR AFFILIATION ALEXICH,M.P. Indiana Michigan Power Co. (formerly Indiana & Michigan Ele RECIP.NAME RECIPIENT AFFILIATION Document Control Branch (Document Control Desk)

SUBJECT:

Application for amend to License DPR-58,extending visual insp interval for inaccessible snubbers.

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indiana Michigan Power Company P.O. Box 16631 Columbus, OH 43216 AEP:NRC:1114 Donald C. Cook Nuclear Plant Unit 1 Docket No. 50-315 License No. DPR-58 SURVEILLANCE INTERVAL EXTENSION FOR UNIT 1, CYCLE 11 U. S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, D. C. 20555 Attn: T. E. Murley February 9, 1990

Dear Dr. Murley:

This letter constitutes an application for amendment to the Technical Specification (T/Ss) for the Donald C. Cook Nuclear Plant Unit 1. Specifically, we request an extension of the visual inspection interval for inaccessible snubbers as delineated in T/S 3/4.7.8 from September 11, 1990 until the Unit 1 refueling outage, currently scheduled for approximately October 12, 1990. This surveillance can only be performed in Mode 5 (cold shutdown);

therefore, to avoid unnecessary shutdown of the plant, we ask that you respond to us by August 31, 1990. The reason for the change and our evaluation concerning significant hazards consideration are provided in Attachment 1. The proposed revised T/S pages are included in Attachment 2.

We believe that the proposed changes will not result in (1) a significant change in the types of effluents or a significant increase in the amounts of any effluent that may by released offsite, or (2) a significant increase in individual or cumulative occupational radiation exposure.

This change has been reviewed by the Plant Nuclear Safety Review Committee and the Nuclear Safety Design Review Committee.

In compliance with the requirements of 10 CFR 50.91(b)(1), copies of this letter and its attachments have been transmitted to Mr. R. C. Callen of the Michigan Public Service Commission and to the Michigan Department of Public Health.

oo'l 900222069K 2 900809 pp315 ADOCK 0+

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Dr. T. E. Murley AEP:NRC 1114 This document has been prepared following Corporate procedures which incorporate a reasonable set of controls to ensure its accuracy and completeness prior to signature by the undersigned.

Sincerely, M. 'P. Alex h Vice President eh cc: D. H. Williams, Jr.

A. A. Blind - Bridgman R. C. Callen G. Charnoff NFEM Section Chief A. B. Davis - Region III NRC Resident Inspector - Bridgman

ATTACHMENT 1 TO AEP:NRC:1114 REASONS AND 10 CFR 50.92 SIGNIFICANT HAZARDS EVALUATION FOR CHANGES TO THE TECHNICAL SPECIFICATIONS FOR COOK NUCLEAR PLANT UNIT 1 to AEP:NRC:1114 Page 1 As discussed in the cover letter, the purpose of this proposed amendment is to delay a September ll, 1990 surveillance outage for inaccessible snubber visual inspection for 46 inaccessible snubbers until the next refueling outage, currently scheduled to begin approximately October 12, 1990. The inaccessibility of the snubbers is such that the surveillance is only practical in Mode

5. We propose to change the surveillance interval requirements of Technical Specification (T/S) 4.7.8.a. on a one time basis by adding the following note to the heading "Subsequent Visual Inspection Period.*¹"

¹¹The visual inspection of inaccessible snubbers may be delayed until the end of the Cycle ll refueling outage.

T/S 3/4.7.8 contains the requirements for snubbers. The snubbers are demonstrated operable by a combination of visual and functional tests delineated in the T/S. If a snubber is not inspected within the required inspection interval, it must be declared inoperable and either restored to operable status or replaced within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />. After this time, the system supported by the snubber must be analyzed or declared inoperable and the T/S action statement for that system followed.

Unit 1 is currently on a 12-month (+ 25%) interval for snubber visual inspections due to a single snubber failure on the June 12, 1989 inspection. The snubber that failed, 1-GRC-S604, would not rotate about its ax'is due to interference from a nearby conduit run. The snubber is located in the pressurizer enclosure on reactor coolant piping. The snubber was removed and functionally tested to ensure this condition had not =rendered the snubber inoperable. The snubber failed the functional test due to a slightly high, tension bleed rate. The snubber was subsequently rebuilt, retested satisfactorily, and replaced. This was the first failure of a visual inspection since May 2, 1985. Since 1978 a total of 17 inspections have been performed with only 7 failures, resulting in a 99.1% passing rate. A review of maintenance records by plant personnel shows no adverse trends in snubber surveillance failures. No snubber will have its service life expire during the proposed surveillance extension.

Because of a combination of extreme area temperatures and ALARA considerations, the plant would have to be brought to Mode 5 to perform the visual inspection of the inaccessible snubbers. We are requesting that relief from the requirements to visually inspect the inaccessible snubbers be granted until the end of the Unit 1 Cycle ll refueling outage.

to AEP:NRC:1114 Page 2 We believe that delaying the visual inspection of the inaccessible snubbers will not adversely impact public health and safety. The snubbers are installed to protect the plant against the consequences of an earthquake. As discussed in Chapter 2.5 of our Updated FSAR, the Cook Nuclear Plant is located in an area of very low seismic activity. No major earthquakes have had epicenters closer than about 400 miles to the plant site. No shocks within 50 miles of the site have been large enough to cause significant structural damage.

Per 10 CFR 50.92, a proposed amendment will not involve significant not:

hazards consideration if the proposed amendment does (1) involve a significant increase in the probability or consequences of a previously evaluated accident, (2) create .the possibility of a new or different kind of accident from any previously analyzed or evaluated, or I

(3) involve a significant reduction in a margin of safety.

Criterion 1 The plant is located in a region of very low seismic activity so the probability of an earthquake is very low. The history of snubber inspections shows a low failure rate giving a good degree of confidence that the snubbers will function if these reasons, we believe the change will not involve a required. For significant increase in the probability or consequences of a previously evaluated accident.

Criterion 2 The change involves no physical modification to the plant, and no changes in plant operation. Therefore, the change should not create the possibility of a new or different kind of accident from any previously analyzed or evaluated.

Criterion 3 The plant is located in a region of very low seismic activity so the probability of an earthquake is very low. The history of snubber inspections shows a low failure rate giving a good degree of confidence that the snubbers will function if these reasons, we believe the change will not involve a required. For significant reduction in a margin of safety.

to AEP:NRC:1114 Page 3 Lastly, we note that the Commission has provided guidance concerning the determination of significant hazards by providing examples (48 FR 14870) of amendments considered not likely to involve a significant hazards consideration. The sixth of these examples refers to changes which may result in some increase to the probability or consequences of a previously analyzed accident or may reduce in some way a safety margin, but where the results of the change are within acceptable limits. For the reasons given above, we believe the delay in performing the snubber functional test will not adversely impact public health and safety. We therefore conclude that the example cited is relevant and that the change should not involve significant hazards considerations.