ML19345A468

Submits Proposed Change 117 to Tech Specs,Limiting Peak Linear Heat Rate Until Results of Revised ECCS Analysis Performed Per 10CFR50,App K Are Available

ML19345A468
Person / Time
Site:	Yankee Rowe
Issue date:	12/30/1974
From:	Vandenburgh D YANKEE ATOMIC ELECTRIC CO.
To:	US ATOMIC ENERGY COMMISSION (AEC)
References
WYR-74-58, NUDOCS 8011210676
Download: ML19345A468 (4)

Text

oropond Changa No. 117 M

pplamant No. 2 Tel: phono 6l7 366-90ll

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TvX 780-390-0739 YANKEE ATOMIC ELECTRIC COMPANY ura,4-SS

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Attention: Directorate of Licensing 2

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Reference:

(1) License No. DPR-3 (Docket No'50-29)

(2)

Proposed Change No. 117, " Revised ECCS Analysis",

submitted to DCL/AEC on July 31, 1974.

(3)

Proposed Change No. 117, Supplement No. 1, " Revised ECCS Analysis", submitted to DOL /AEC on December 12, 1974.

(4)

" Yankee Nuclear Power Station Revised Loss Of Coolant Analysis", IAC analysis submitted to AEC on January 15, 1972.

(5)

" Additional Infor=ation on the Possible Effects of Fuel Densification on Subsequent Cperation of Yankee Rcwe Cycle X" Proprietary, submitted to the Atomic Energy Ccemission by Yankee Atcmic Electric Ccmpany on Cctober 17, 1973.

(6)

Non-Proprietary Version of Reference 5.

Subject:

Failure of Low Pressure Safety Injection Pumps to Deliver the Flow Rates Assumed in the ECCS Analysis

Dear Sir:

Pursuant to Section 50.59 of the Ccemission's Rules and Regulations, the Yankee Atomic Electric Company hereby submits the following Supplement No. 2 to Proposed Change No. 117 Geference 2) thereby superceding Supplement No. 1 (Reference 3).

PROPCSED CHANGE: Reference is made to Section D.2.c of the Technical Specifications, Appendix A of License No. DPR-3.

We propose to limit the peak linear heat ra~e to 11.65 kw/ft until results of a revised ECCS analysis, performed in..:cordance with Appendix K of 10 CFR Part 50 are available.

REASON FOR CHANGE: Safety injection performance tests at the Yankee Nuclear Power Station have shown that pumped ECCS flow rate at runout conditions is less than the flow assumed in the ECCS analysis.

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c Unitsd States Atomic Enargy Commission Dscember 30, 1974 Attn: Directorate of Licensing Page Two DESCRIPTICN CF CHANGE:

It is requested that the following revision be made to the above mentioned section of the Technical Specifications of 7

the referenced license.

Section D.2 Operating Limits c.

Thermal Revise paragraph (1) to read as follows:

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"(1)

At rated power, F, the nuclear heat flux hot channel factor, f8r the hottest point in the hottest channel shall not exceed 2.42.

Further-more, the peak linear heat rate during power operation shall not exceed 11.65 kw/ft. These l

values shall be checked every 1000 equivalent full power hours of operation utilizing data derived from core instrumentation."

SAFETY CONSIDERATICNS: It is our finding that the_ station safety injection pumps have not suffered a deterioration in their delivery capability rather, the pumped ECCS ' capacity at runout conditions assumed in ~ the ECCS analyses is incorrect. Furthermore, until now, this discrepancy has been masked by use of an incerect conversion factor in the ECCS flow test procedure resulting 2

in artificially high ECCS flow rates. A conservative effects analysis has been performed by Yankee Atomic Electric Ccmpany to determine what additional plant limitations should be je g gagly imposed to maintain previously demonstrated safety margins.

It is required that Yankee Rowe be operated according to the more limiting of the Interim Acceptance Criteria (IAC) analysis or the Final Acceptance Criteria (FAC) analysis. Thus, possible additional plant restrictions were evaluated on the basis of the results of both the FAC and the IAC analyses.

The approach taken was to examine the worst break sizes (the double-2 ended cold leg guillotine with a discharge coefficient of 0.6 for FAC; 0.5 ft cold leg split for IAC) and conservatively determine'the additional times required to bring the fluid inventories in the reactor vessel to the point where the clad temperature rise is terminated. Reduced linear heat rates-which should yield the same peak clad temperatures shown in the FAC and IAC' analyses were then calculated. The assumptions made in these calculations l

are discussed belo :

1.

The two-train pumped ECCS flow at runout without the accumulato:

is conservatively estimated to be 2180 gpm rather than the 2480' gym assumed in the original analyses; 2.

It.is conservatively: assumed that'a reduction in the peak linear heat rates does not improve the shape of the clad temperature transient during the non-linear metal-water reaction period:

3.

It is assumed that the clad temperature at the initiation of the adiabatic heatup phase is not lowered by a reduction in the peak l

linear heat peak.

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Unit,ed States Atomic Energy Ccemission December 30, 1974 Attn Directorate of Licensing Page Three Based on these assumptions, new linear heat rate limits of 12.73 kw/ft (FAC) and 11.65 kw/ft (IAC) were calculated.

The Yankee Nuclear Power Station is currently being cperated at a power level such that the peak linear heat rate does not exceed 11.65 kw/ft.

The plant will continue to observe this limit until results of a revised ECCS analysis are available.

This supplement to Proposed Change No. 117 has been reviewed by the Nuclear Safety Audit and Review Committee.

SCHEDULE OF CHANGE: We respectfully request review of this supplement by the Commission as soon as possible.

Any questions regarding this supplement should be directed to Mr. A. E. Ladieu at our Engineering Office, 20 Turnpike Road, Westboro, Massachusetts, 01581 (617) 366-9011, extension 2845.

Respectfully submitted, YANKEE ATCMIC ELECTRIC COMPANY k ': -

D.

. Vandenburgh Vice President CCMMONWEALTH CF MASSACHUSETTS)

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COUNTY OF WOECESTER

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l Then personally appeared before me, D. E. Vandenburgh, who being duly l

sworn, did state that he is a Vice President of Yankee Atomic Electric l

Company, that he is duly authorized to file, execute and sign the foregoing j

reque.st in the name and on the behalf of Yankee Atomic Electric Ccmpany, and i

that the statements therein are true to the best of his knowledge and belief.

1 Armand R. Soucy Notary Public My Commission Expires September 9, 1977 1

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_ AEC DISTRISUTIC': FOR PART 50 DOCKET.'.1 ATERI AL (TE.iPOR ARY FORT.1) 129 CONTROL NO:

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Yankee At mic Elect. Co.

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Mr. D.E. Vandenburgh 12-30-74 1-6-74 Y

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DESCRIPTION:

ENCLOSU R ES:

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40 Ltr rcquesting an andt to the OL... consist of Suppl #2 to tech spec change No. 117...

r3 change to tach specs...concerning..........

Reviced ECCS Analysis....trans the following...

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