ML20211C018

Application for Amends to Licenses DPR-39 & DPR-48,revising Tech Specs to Allow one-time Change & Extend Allowable Outage Time on Diesel Generator O from 7 to 21 Days.Fee Paid

ML20211C018
Person / Time
Site:	Zion  File:ZionSolutions icon.png
Issue date:	02/10/1987
From:	Leblond P COMMONWEALTH EDISON CO.
To:	Harold Denton Office of Nuclear Reactor Regulation
Shared Package
ML20211C023	List: ML20211C018 ML20211C032
References
2704K, NUDOCS 8702190672
Download: ML20211C018 (4)

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. Commonwealth Edison s;' d One First National Plaza. Chicago, Illinois

' Address Reply to: Post Office Box 767

~_- Chicago, Illinois 60690 - 0767 February 10, 1987 Mr. Harold R. Denton, Director Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Washington, DC 20555

Subject:

Zion Nuclear Power Station Units 1 and 2 Proposed Amendment to Facility Operating License Nos. DPR-39 and DPR-48 "O" Diesel Generator Outage Time NRC Docket Nos. 50-295 and 50-304 References (a): December 16, 1985 letter frcm P. C. LeBlond to H. R. Denton.

(b): October 14, 1983 letter from F. G. Lentine to H. R. Denton.

(c): December 22, 1983 letter from F. G. Lentine to H. R. Denton.

(d): March 12, 1984 letter from J. A. Norris to D. L. Farrar.

Dear Mr. Denton:

Attachment I to this letter is a proposed amendment to Facility Operating License Nos. DPR-39 and DPR-48, Appendix A, Sections 3.15/4.15, Auxiliary Electrical Power System. This is a one-time change that will extend the allowable outage time on the "O" diesel generator from 7 days to 21 days for the Spring, 1987 Unit 2 refueling outage. This extended outage period is required to complete required modifications as discussed in reference (a) and perform an extensive refueling outage maintenance program. Attachment 2 summarizes the work that is intended to be performed during the 21 day outage.

"O" diesel generator supplies power both to Unit 1 and Unit 2 Emergency Safeguards Features (ESP) buses. As a result, the current Zion Technical Specifications would require a dual unit shutdown for any outage period in excess of 7 days for "O" diesel generator. This constraint limits 8702190672 DR G70210 D ADOCK 0500l 5 6

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. o Mr. H. R. Denton February 10.-1987

. Commonwealth Edison Company's ability to effectively maintain "O" diesel generator. Thus, this proposed amendment is intended to integrate the required Appendix R modifications with an extensive maintenance program intended to maintain "O" diesel generator's reliability.

This change is virtually identical to the previously approved Amendment Nos. 84/74 to the Zion Technical Specifications. This previous amendment request was submitted in references (b) and (c) and was approved by the NRC in reference (d). The only deviation from the previously approved amendment request involves a reduction in the requested time period from 45 days to the 21 days contained in this request. In addition, the requirements of page 255b are being formally incorporated in this change request.

Previously, Commonwealth Edison Company has informally impicmented these constraints without their inclusion in references (b), (c) or (d).

The justification for this _ change is as follows:

(1) The multiple sources of offsite power that are a feature of the Zion design exceed the requirements of 10CFR50, Appendix A, criterion 17.

The probability of a total loss of offsite power during the 21 day period is acceptably low.

Attachment 3 lists the sources of power available to ESF bus 147 (typical of all ESF buses). Even with diesel generator "O" out-of-service, up to four additional sources of power may be available, depending on the operating status of Unit 1.

Attachment 4 summarizes the conclusion of the Zion Probabilistic Safety Study regarding loss of offsite power. Due to the reliable design of the switchyard ring-bus (featuring six incoming lines) and the historical stability of the Commonwealth Edison System, the' probability of occurrence of a total loss of offsite power at Zion is considerably less than the industry average.

(2) The redundancy and diversity of the ESF buses and equipment ensures that the minimum safeguards capability specified in the FSAR analyses will be maintained, even without power to ESF buses 147 and 247 (served by diesel generator "O").

Attachment 5 provides a table of the ESF equipment' powered from each bus. Attachment 6 provides a table of the minimum number of components required to meet accident analyses. These tablos illustrate that all minimum requirements are met with no power to buses 147 and 247.

All work performed on the diesel generator will be performed as expeditiously as possible with many of the tasks discussed in Attachment 2 being performed concurrently. Every attempt will be made to return the diesel generator to service prior to the requested 21 days, thus minimizing the outage period.

Mr. H. R. Denton February 10, 1987 Attachment 7 to this letter is a demonstration that the issue involves no significant hazards consideration. The proposed amendment has received on-site and off-site review and approval.

In accordance with 10 CFR 170, a fee remittance in the amount of

$150.00 is enclosed. As provided by 10 CFR 50.91, the State of Illinois is being notified of this amendment request by transmittal of this letter and the attachments.

The Zion Unit 2, Spring, 1987 outage is scheduled to begin on March 5, 1987 with an approximate fifteen week duration. Thus, Commonwealth Edison Company is requesting NRC approval of this change by April 17, 1987 to facilitate the integration of the "O" diesel generator work with the remainder

! of the planned refueling outage.

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! One signed original and thirty-seven (37) copies of this letter and its attachments are enclosed for your review.

Please direct any questions you may have concerning this matter to this office.

Very truly yours, p g 4.R J P. C. LeBlond Nuclear Licensing Administrator im Attachsents cc: Region III Inspector - Zion J. A. Norris - NRR M. C. Parker - IDNS Regional Administrator - RIII SUBSC BED AND to beforfmfthis . day

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5 ATTACHIENT 1 ,,

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b PROPOSED CRANGES TO APPENDIX A TECHNICAL SPECIPICATION i SECTIONS 3.15 AND 4.15 AUXILIARY ELECTRICAL POWER SYST8M /

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