ML19309B032

Order Modifying License DPR-54 Re Proposed ECCS Performance Tech Specs.Diagrams Encl

ML19309B032
Person / Time
Site:	Rancho Seco
Issue date:	12/27/1974
From:	Case E US ATOMIC ENERGY COMMISSION (AEC)
To:	US ATOMIC ENERGY COMMISSION (AEC)
Shared Package
ML17054D216	List: ML17054D214 ML19309B029 ML19309B032 ML19309B035
References
NUDOCS 8004020508
Download: ML19309B032 (9)

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UNITED STATES OF AMERICA

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ATOMIC ENERGY COMMISSION

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Docket No. 50-312 iEi+E

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(Rancho Seco Nuclear Generating

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ORDER FOR MODIFICATION OF LICENSE

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The Sacramento Municipal Utility District (the licensee) is the holder of

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facility license DPR--5'4, which authorizes operation of the Rancho Seco Nuclear Generating Station, Unit 1 in Sacramento County, California. This m

license provides, among other things, that it is subject to all rules, regulations and orders of the Commission now or hereafter in effect.

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Pursuant to the requirements of the Commission's regulations in 10 CFR S 50.46, " Acceptance Criteria and Emergency Core Cooling-Systems for Light Water Nuclear Power Reactors", on August 2, 1974, the licensee submitted an evaluation of ECCS cooling performance calculated in accordance with an evaluation codel developed by the Babcock & Wilcox Company ("the vendor"),

l along with certain proposed technical specifications necessary to bring reactor operation into con'formity with the results of the evaluation.

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• Fi The evaluation model developed by the vendor has been analyzed by the Regulatory staff for conformity with the requirements of 10 CFR Part 50,

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Appendix K, "ECCS Evaluation Models". The Regulatory staff's evaluation of the vendor's model is described in two previously published documents:

Status Report by the Directorate of Licensing in the Matter of Babcock and Wilcox ECCS Evaluation Model Conformance to 10 CFR Part 50, Appendix K, issued October 15, 1974, and a Supplement to the Status Report, issued November 13, 1974.

Based on its evaluation, the Regulatory staff has

=E concluded that the vendor's evaluation model was not in complete conformity 2

with the requirements of Appendix K and that certain modifications described in the above-mentioned documents were required in order to achieve such conformity. The Regulatory staff assessments were reviewed by the Commission's Advisory Committee on Reactor Safeguards in meetings held on October 26, 1974, and November 14, 1974.

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4 In its Report to the Chairman of the AEC, dated November 20, 1974, the sq.j

1 Advisory. Committee has concluded that "the four light-water reactor vendors have developed Evaluation Models which, with additional modifications required by the Regulatory staff, will conform to Appendix K to Part 50".

Since the licensee's evaluation of ECCS cooling performance is based upon the vendor's evaluation model, the licensee's evaluation is similarly qv deficient. The Regulatory staff has assessed the'effect of the changes

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~1 required in the evaluation model upon the results of the evaluation of

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ECCS performan'ce for Rancho Seco Nuclear Generating Station, Unit 17 submitted on August 2, 1974. This is described in the Safety Evaluation Report of the Ranche Seco Nuclear Generating Station, Unit 1, dated December 27, 1974. On the basis of its review, the Regulatory staff

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has determined that the operating limitations for the plant proposed in the licensee's submittal of August 2, 1974 will assure that ECCS cooling performance will conform to all of the criteria contained in 10 CFR S 50.46(b),

which govern calculated peak clad temperature, maximum cladding oxidation, maximum hydrogen generation, coolable geometry and long term cooling. A

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further limitation based on different considerations concerning control rod ejection, submitted by the licensee on December 6, 1974, results in slightly more restrictive limits than those of the licensee's August 2, 1974 submittal. These are included in Appendix A to this Order.

The Regulatory staff believes that these limitations should be verified by a re-analysis based upon an approved evaluation model, in conformity with 10 CFR 5,50.46 and Appendix K.

During the interim, before an evaluation in conformity with the requirements of 10 CFR S 50.46 can be submitted and evaluated, the Regulatory staff has concluded that continued conformance to the requirements of the Commission's Interim Acceptance Criterit should be required in addition to conformance to the restrictions contained in the licensee's August 2, 1974 submittal as modified by Appendix A.

These limitations will provide reasonable assurance that the public health and safety will not be endangered.

• Interim Acceptance Criteria for Emergency Core Cooling Systems for Light Water Power Reactors, 36 F.R.12247, June 29,1971, as amended 36 F.R. 24082, December 18, 1971

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A In view of the foregoing, and in accordance with the provisions of 5 50.46(a)(2)(v), the Acting Director of Licensing has found that the evaluation of ECCS cooling performance submitted by,the licensee is not conelstent with the requirements of 10 CFR 5 50.46(a)(1) and, therefore, that further restrictions on facility operation as set forth in

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this Order, are required to protect the public health and safety. The Acting Director of Licensing has also found that the public health, safety, and interest require that the following Order be made effective immediately.

Pursuant to the Atomic Energy Act of 1954, as amended, the Commission's regulations in 10 CFR S 5 2.204, 50.46 and 50.54, IT IS ORDERED THAT:

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As soon as practicable, but in no event later than six months from the date of publication of this order in the FEDERAL REGISTER, or prior to any license amendment authorizing any core reloading, whichever occurs first, the licensee shall submit a re-evaluation of ECCS cooling performance calculated in accordance with an acceptable evaluation model which conforms with the provisions of 10 CFR Part 50, 5 50.46. Such evaluation may be based upon the vendor's evaluation model as modified in accordance with the changes described in the Safety Evaluation Report of the Rancho Seco Nuclear Generating Station, Unit 1, dated December 27, 1974. The evaluation shall be accompanied by such proposed changes in Technical Specifications or

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license amendments as may be nraessary to implement the evaluation'results.

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Effective 1:nmediately resctor operation shall continue only within

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the limits of:

(a) The requirements of the Interim Acceptance Criteria, and the Technical Specifications, and license conditions imposed by the Commission in accordance with the requirements of the Interim Acceptance Criteria, and (b) The limits of the proposed Technical Specifications submitted by the licensee on Augut 2,1974, as odified by the restrictions setforth sj,,

in Appendix A, attached hereto.

The licensee shall conform operation to the foregoing 1. imitations until such time as the proposed Technical Specifications required to be submitted in accordance with paragraph 1 above are approved or modified *and issued by the Cocmission.

Subsequent notice and opportunity for hearing will be provided in connection with such action.

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Within thirty (30). days from the date of publication of this Order in the FEDERAL REGISTER the licensee may file a request for a hearing with respect g

to this Order. Within the same thirty (30) day period, any other person whose interest may be affected may file a request for a hearing with respect to this Order in accordance with the provisions of 10 CFR 5 2.714 of the

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- sis Comission's Rules of Practice. If a request for a hearing is filed within 5

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the time preeribed herein, the Commission will issue a notice of hearing

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,.or.an appropriate order.

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"25=x For further details with respect to this action, see (1) the licensee's E=

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submittals dated August 2, 1974 and December 6, 1974, and vendor's topical reports referenced in the licensee's submittal, which describe the vendor's evaluation model, (2) the Status Report by the Directorate of Licensing in the Matter of Babcock & Wilcox ECCS Evaluation Model Conformance to 10 CFR 5f 50, Appendix K, (3) Supplement 1 thereto dated Novemlier 13,1974, (4) the lh$

Safety Evaluation Report dated December 27, 1974, and (5) Report of the

ht.1 Advisory Committee on Reactor Safeguards Jared November 20,'1974. All of

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these items are available at the Commission's Public Document Room, 1717 H

• =7 Street, N. W., Washington, D. C. and at the Business and Munic1 pal Department, T.'.'~

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Sacraento City-County Library, 828 I Street, Sacranento, California, A single copy each of items (2) through (5) may be obtained upon request

,8 addressed to the U, S. Atomic Energy Commission, Washington, D. C.

20545, Attention: Deputy Director for React:ar Projects, Directorate of Licensing, Regulation.

Dated at Bethesda, Maryland, this of DEC. l

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FOR THE ATOMIC ENERGY COMMISSION

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i O'E nal Signd Br.

i E. G. Case s

Edson G. Case Acting Director of Licensing

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APPE'! DIX A OPgPI. tit!G REST 91CTIO"S The Regulato'ry staff has reviewed the methods uscd by Babcock,

e and Wilcox to derive the LOCA-related oporreting limits for its plants.

The review considered the basic calculation cethod, the range of operating conditions calculated, the types of uncertainties and their magnitudo, and the instrumentation provided to conitor plant operation.

Based on this revicu, we ccnclude that sufficient mor.itoring instru-mentation is present to provide assurance that the plant cay be operated within LOCA related operating restrictions. We further conclude that e

operation of Eancho Seco Unit 1, within the restrictions shown on Figure A-1, will assure that the heat generation linits of Figure A-2 uill not to excecded.

Operation of the facility shall conform with' tha valuas set forth in these Figures.

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100 195,7, 94.5 90 177.7,94.5 1

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PERMISSIBLE OPERATING REGION 20

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.200 ROD INDEX,KVITHDRAWN O

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ROD INDEX IS THE PERGENTAGE SUM OF THE WITHDRAWAL OF CONTROL ROD GROUPS 5,6, & 7.

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