ML19338E932

Application to Amend License DPR-65 Authorizing Performance of Tests at Reduced RCS Inlet Temps in Order to Quantify Secondary Plant Performance Losses

ML19338E932
Person / Time
Site:	Millstone
Issue date:	09/30/1980
From:	Counsil W, Fee W NORTHEAST NUCLEAR ENERGY CO.
To:	Clark R Office of Nuclear Reactor Regulation
Shared Package
ML19338E933	List: ML19338E932 ML19338E936
References
B10092, TAC-11348, TAC-11561, TAC-11793, TAC-12505, TAC-42846, NUDOCS 8010060323
Download: ML19338E932 (4)

Text

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September 30, 1980 Docket No. 50-336 B10092 Director of Nuclear Regulation Attn: Mr. R. Clark, Chief Operating Reactors Branch #3 U. S. Nuclear Regulatory Commission Washington, D. C. 20555

Reference:

(1) D. K. Davis letter to A. E. Lundvall, forwarding Calvert ,

Cliffs, Unit No. 1 Stretch Power Safety Evaluation Report, I dated September 9, 1977.

(2) W. G. Counsil letter to R. Reid dated December 27, 1980.

(3) R. Reid letter to W. G. Counsil dated April 29, 1980.

(4) W. G. Counsil letter to R. Clark dated May 9, 1980.

Gentlemen:

Millstone Nuclear Power Station, Unit No. 2 Low Temperature Testing Pursuant to 10CFR50.90, Northeast Nuclear Energy Company (NNECO) hereby proposes to amend its operating license, DPR-65, for Millstone Unit No. 2 to authorize performance of tests at reduced reactor coolant system inlet temperatures, as aescribed in Attachment 1.

During norma' operation, Millstone Unit No. 2 operates with three of the four turbine control valves fully open and the fourth valve partially open. In an effort to quantify secondary plant performance losses, it is desired to fully open the fourth turbine control valve and thus, determine the throttling loss across this valve. Since this test will be performed at 100% power, the in-crease in steam flow will be offset by a reduction in steam enthalpy and herce, steam temperature. The reduction in secondary system temperature will result in a reduction in primary system. temperature of approximately 10*F.

The reduction in core inlet temperature during this test will be such that  !

the inlet temperature will be outside the range of temperatures used in the l docketed Cycle 4 safety analyses. NNECO has determined that this constitutes an unreviewed safety question pursuant to 10CFR50.59, and therefore, has per-formed an engineering evaluation addressing the expected effects of this short duration test and the precautions that will be taken to ensure conversatism with respect to the Cycle 4 safety analyses. This evaluation is provided as Attachment 2.

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• s In Reference (2), NNECO had previously requested permission to perform the turbina control valve wide open test during Cycle 3. Subsequently, the Staff approved the Reference (2) request in Reference (3).

NNECO has determined that low temperature testing can be performed safely I based on the following: l (1) The duration of the test is not expected to exceed twenty four (24) hours, during which time the necessary data will be collected.

Following the test, the plant will be returned to normal operating i conditions..

(2) Although the moderator temperature coefficient will change slightly during the valves wids open' test due to temperature and boron concentration variations, it will not be outside the range of values used in the Cycle 4 safety analysis.

(3) The conduct of the test and the administrative restrictions which will be in effect will assure that the results of transients or i

accidents initiated during the test will be less severe than indicated in the Cycle 4 safat.y analyses. Specifically, the following operating conditions will be adhered to:

o Minimum inlet temperature 3.537'F.

o Maximum linear heat rate i 14.2 KW/Ft.

o Pressurizer level'will not be varied with the reduced average temperature.

l NNECO has determined from the review of the safety analyses that transients and accidents initiated'from the lower temperature than previously analyzed will in fact be bounded by the results of the Cycle 4 safety analyses. In addition, the short duration of the test significantly reduces the probability of occurrence of any of these' events during the test interval.

NNECO has determined that this action will constitute an unreviewed safety question; therefore, pursuant to 10CFR50.90, proposes the Tech-nical Specification included as Attachment 1. Restrictions which will be in effect during the test will assure that operations will be bounded by analyses and results submitted to the. 3RC in support of Cycle 4 operation.

The Millstone Unit No. 2-Nuclear Review Board has reviewed and approved this proposed change and has concurred in the'above determinstion.

NNECO has reviewed this request pursuant to 10CFR170 and has determined that the' request constitutes a Class III amendment. In addition, NNECO has determined that tho' proposed license amendment is a direct consequence of the Cycle 4 Reload effort for which the' appropriate license amendment fee for a Class IV change has been forwarded in Reference (4).

i . o In addition, NNECO is required by Technical Specifications to perform moderator temperature coefficient (MTC) testing at various times during each fuel cycle.- The accepted method for performing this test involves lowering the primary system temperature while measuring the amount of negative reactivity which must be inserted by control rod motion to maintain reactor criticality.

We trust the above information is sufficient for you to concur with our conclusion that this test may be performed safely and with no adverse consequences.

Very truly yours, NORTHEAST NUCLEAR ENERGY COMPANY o

r W. G. Giunsil Senior Vice President By:

• W. F. Fee Executive Vice President Attachment i

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) a n:.  ?:rlin b 30,/4/U COUNTY OF HARTFORD )

Then personally appeared before me W. G. Counsil, who being duly sworn, did state that he is Senior Vice President of Northeast Nuclear Energy Company, a Licensee herein, that he is authorized to execute and file the foregoing information in the name and on behalf of the Licensees herein and that the statements contained in said information are true and correct to the best of his knowledge and belief.

'~ Notary Public th y k n Erf fitJ 3/,l'io e

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