ML20090D411

Application for Amend to Licenses DPR-42 & DPR-60,changing Tech Specs Re Steam Generator Operability,Per NRC 840706 Request,To Allow Continued Operation W/Three Defected Tubes Until Next Refueling Outage

ML20090D411
Person / Time
Site:	Prairie Island
Issue date:	07/09/1984
From:	Musolf D NORTHERN STATES POWER CO.
To:
Shared Package
ML20090D408	List: ML20090D406 ML20090D411 ML20090D415
References
TAC-55237, NUDOCS 8407180233
Download: ML20090D411 (3)

Text

- s UNITED STATES NUCLEAR REGULATORY COMMISSION NORTHERN STATES POWER COMPANY PRAIRIE ISLAND NUCLEAR GENERATING PLANT Docket No. 50-282 50-306 REQUEST FOR AMENDMENT TO OPERATING LICENSE NOS. DPR-42 & DPR-60

-License Amendment Request Dated July 9, 1984 Northern States Power Company, a Minnesota corporation, requests authorization for changes to the Technical Specifications as shown on the attachments labeled Exhibit A and Exhibit B. Exhibit A describes the proposed changes along with reasons for the change. Exhibit B is a set of Technical Specification pages incorporating the proposed changes.

This letter contains no restricted or other defense information.

NORTHERN STATES POWER COMPANY By David Musoif T Manager - Nuclear Support Services On this 4d day of Oo /w , /MM before me a notary public in and for said County, personally (fippe d ed David Musolf, Manager - Nuclear Support Services, and being first duly sworn acknowledged that he is authorized to execute this document on behalf of Northern States Power Company, that he knows the contents thereof and that to the best of his knowledge, information and belief, the statements made in it are true and that it is not interposed for delay.

8407180233 840709 PDR ADOCK 05000282 P PDR

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Exhibit A Prairie Island Nuclear Generating Plant License Amendment Request Dated July 9, 1984 Evaluation of Proposed Changes to the Technical Specifications Appendix A of Operating License DPR-42 and DPR-60 Pursuant to 10 CFR Part 50, Sections 50.59 and 50.90 the holders of Operating Licenses DPR-42 and DPR-60 hereby propose the following change to Appendix A, Technical Specifications:

STEAM GENERATOR TUBE SURVEILLANCE Proposed Change Add the. following exception to paragraph TS.4.12.D.2:

"Except for three' tubes identified in a letter dated June 18, 1984 from NSP to Director of NRR during Unit 1, Cycle 9."

Reason For Change

.Three eddy current indications were recently discovered through re-evaluation of eddy current test data to exceed the Technical Specifi-cation plugging criteria. This Technical Specification change is required because the NRC Staff has determined that the Technical Specification requiring plugging of these tubes is applicable during plant operations.

Significant Hazards Evaluation The eddy current indications suggest that three tubes are potentially degraded. These indications are located in the tube sheet crevice area. Also, the eddy current signals suggest short indications less than 0.5 inches. Due to the location in the tubesheet crevice area, any leakage that does occur would be restrictad to less than 10 gpm if - all three tubes would fail under accident cor.ditions . The length of the tubesheet above the elevation of the indications creates a tight

. annulus around the tube that acts as a leak- .miting orifice. This constraining annulus will also act against tuue burst and double ended rupture by restricting the crack opening and the tube separation if the tube should continue to degrade. Further information is provided in our June 18, 1984 letter.

I This change will only be effective during the remainder of Unit 1, Cycle 9 operation (approximately 6 months). The steam jet air ejector monitor and secondary side chemistry samples will identify any degradation of the tubes. These three identified tubes will be plugged at the next refueling outage.

For these reasons, operation of Unit 1 of the Prairie Island Nuclear Generating Plant in accordance with this proposed change will not:

(1) involve a significant increase in the probability or consequences of an accident previously evaluated; or (2) create the possibility of a new or different kind of accident from any accident previously evaluated; or (3) involve a significant reduction in a margin of safety.