B10913, Application for Amend to License DPR-65,revising Tech Specs Re Pressurizer Level Band

Application for Amend to License DPR-65,revising Tech Specs Re Pressurizer Level Band

ML20080T268
Person / Time
Site:	Millstone
Issue date:	10/12/1983
From:	Counsil W NORTHEAST NUCLEAR ENERGY CO., NORTHEAST UTILITIES
To:	John Miller Office of Nuclear Reactor Regulation
Shared Package
ML20080T270	List: B10913, Application for Amend to License DPR-65,revising Tech Specs Re Pressurizer Level Band ML20080T286
References
B10913, TAC-52504, NUDOCS 8310200229
Download: ML20080T268 (4)

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• • "'""'"'"'"*" HARTFORD, CONNECTICUT 06141-0270 onewast uvuus seaus cow = (203) 666-6911 countw a518e> Clean gwaGv COh.Pw October 12,1983 Docket No. 50-336 B10913 Director of Nuclear Reactor Regulation Attn: Mr. James R. Miller, Chief Operating Reactors Branch #3 U. S. Nuclear Regulatory Commission Washington, D. C. 20555

References:

(1) W. G. Counsil letter to R. A. Clark, dated April 13,1983.

Gentlemen:

Millstone Nuclear Power Station, Unit No. 2 Proposed Revisions to Technical Specification Modification of the Pressurizer Level Baj Pursuant to 10 CFR 50.90, Northeast Nuclear Energy Company (NNECO) hereby proposes to amend its cperatir.g license, No. DPR-65 for Millstone Unit No. 2, by incorporating the changes identified in Attachment 1 into the Millstone Unit No. 2 Technical Specifications.

The attached changes are proposed to revise the pressurizer level band from the ,

current pressurizer level band of +5 percent of its programmed value to a band greater than or equal to 525 f t 3 bTit less than or equal to 1020 f t3 during periods of normal operation.

The present requirements of Millstone Unit No. 2 Technical Specifications Section 3.4.4 state that the pressurizer level be maintained at the programmed level of 40 25 percent for entry into Mode 4. This requirement results in an inability to effectively cool the pressurizer during the first phase of cooldown.

That is, once the reactor coolant pumps are secured, use of the pressurizer auxiliary spray is required. This has resulted in pressurizer spray differential temperatures approaching 3500F. To avoid this situation, it is desirable to follow pre-TMI operating practice of raising pressurizer level to approximately 70 percent prior to initiation of cooldown.

Additionally, pressurizer level change is used as a method in determining the rate of Reactor Coolant System (RCS) leakage. The sources of RCS leakage often are the charging pump seals and/or the Chemical and Volume Ccatrol System (CVCS) relief valves. To determine if this is the case, the CVCS is isolated and the pressurizer level should slowly f all due to inventory loss thro'igh the reactor coolant pump seals. If the level drop matches the reactor coolant pump seal inventory loss, it can be concluded that the unidentified RCS leakag 8310200229 831012 PDR ADOCK 05000336 P PDR /

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is due to leakage in the CVCS. With a 35percent level band, only 90 minutes of data for the RCS leakage determination can be obtained and this is not sufficient to provide statistically meaningful data. Therefore, NNECO has proposed the Attachment I revisions to the pressurizer level band to allow greater flexibility and thus eliminate the above described operational problems presently being experienced at Miiistone Unit No. 2.

The remaining changes identified in Attachment I call for the limiting condition for operation to require two groups of pressurizer heaters, each with a capacity of 130 KWs, during Modes I through 3, and a revised more restrictive pressurizer heater action statement.

An evaluation was performed for all full power non-LOCA design basis events as to the impact of the pressurizer level change. For overheating events, where the concern is overpressurization, the limiting conditions are full power and maximum pressurizer level. As the proposed change does not affect the total

%able range of the pressurizer level from full power to zero power, the pu. . analyses for overheating events are still applicable. Similarly for overtoom *nts, the limiting conditions are zero power and minimum pressurizer au Since the proposed change does not alter the minimum allowable pressuri,.er level at zero power, overcooling design basis events remain unaffected.

The impact of this change on the Icss of coolant accident (LOCA) has been investigated. An evaluation of the small break LOCA indicates that the lower pressurizer level of 35 percent of span results in draining the pressurizer 20 seconds earlier and consequently minimum core inventory and peak clad temperature occur 20 seconds sooner. Although this results in a slight increase in calculated peak clad temperature (140F), changes in cladding oxidation are insignificant. The results of the small break LOCA remain within the acceptance criterion of 10CFR50 Appendix K and the consequences of this event are not increased by this change. There is no impact on the large break LOCA analysis from the proposed changes.

The above discussed changes have been reviewed pursuant to the requirements of 10 CFR 50.59 and have not been found to constitute an unreviewed safety question. The information discussed herein supports this conclusion in that none of the criteria of 10 CFR 50.59(a)(2) are compromised.

NNECO has reviewed the attached proposed license amendment pursuant to the requirements of 10 CFR 50.91(a) and has determined that the proposed changes of Attachment I do not involve a significant hazards consideration. The basis for this conclusion is that none of the criteria delineated in 10 CFR 50.92 have been compromised. That is, the proposed changes do not involve a significant increase in the probability or consequences of an accident previously evaluated; or involve a significant reduction in a margin of safety.

Therefore, the proposed change to the current pressurizer level band falls within the envelope of example (vi) of the examples provided in 48 FR 146864 of license amendments likely to involve no significant hazards considerations. Specifically, the proposed allowable level band in Modes 1 through 3 does not adversely impact any consequences of the transients and accidents analyzed in the FSAR.

__ . .. ~. ___ - _ _ . . . . _ .- . -_ _._ . -

The proposed change to require two groups of pressurizer heaters each with a capacity of 130 KWs and the changes to the corraponding action statements constitute a additional limitation or control from the current technical specification and f alls within example (ii) of 48 FR 14864 of license amendments not likely to involve a significant hazards consideration.

The Millstone Unit No. 2 Nuclear Review Board has reviewed and approved the

, attached proposed changes and concurs with the above determinations.

In accordance with 10 CFR 50.91(b), a copy of this document is being provided to the State of Connecticut.

NNECO has reviewed the attached proposed changes pursuant to the requirements of 10 CFR 50.170 and has determined that this application can be treated in conjunction with the review required for the Cycle 6 reload. NNECO has previously concluded that the Cycle 6 reload will constitute a Class IV license amendment. The basis for this determination was provided in Reference (1). The applicable license amendment fee was also provided at that time.

We remain available to assist the Staff to f acilitate the review of the attached proposed changes.

Very truly yours, NORTHEAST NUCLEAR SERVICE COMPANY i' W. G. Counsil I Senior Vice President i

I i cc: Mr. Arthur Heubner Director, Radiation Control Unit Department of Environmental Protection State Office Building Hartford, CT 06116

_4 STATE OF CONNECTICUT )

) ss. Berlin 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 inforination 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.

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