ML19211C514
| ML19211C514 | |
| Person / Time | |
|---|---|
| Site: | Millstone  |
| Issue date: | 12/27/1979 |
| From: | Counsil W NORTHEAST NUCLEAR ENERGY CO. |
| To: | |
| Shared Package | |
| ML19211C515 | List: |
| References | |
| TAC-11793, NUDOCS 8001110557 | |
| Download: ML19211C514 (2) | |
Text
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NOR'ITIIIAST ITTII.Fril!S PO box 270
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HARTFORD. CONNECTICUT 06101
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December 27, 1979 Docket No. 50-336 Director of Nuclear Reactor Regulation Attn:
Mr. R. Reid, Chief Operating Reactors Branch #4 U. S. Nuclear Regulatory Commission Washington, D. C.
20555
Reference:
(1)
D. R. Davis letter to A. E. Lundvall, forwarding Calvert Cliffs, Unit No. 1, Stretch Power Safety Evaluation Report, dated September 9,1977.
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 described in Attachment 1.
Currently, 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 quantif y secondary plant performance losses, it is desired to fully open the fourth turbine control valve and thus, determine the throttling loss across tlis valve.
Since this test will be performed at 1007. power, the increase in stea u flov will be off set by a reduction in steam enthalpy and hence, steam tempera.ture. 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 the test will be such that the inlet temperature will be outside the range of temperatures used in the docketed safety analyses.
NNECO has determined that this constitutes an unreviewed safety question pursuant to 10CFR50.59, and, therefore, has performed an engineering evaluation addressing the expected effects of this short duration test and the precautions that will be taken to ensure conservatism with respect to existing safety analyses.
This evaluation is provided as.
1742 030 8001110 C f 2 f2 NNECO has determined that this test can be performed saf ely based on the following:
(1) The duration of the test is not expected to exceed twenty fc'ir (24) hours, during which time the necessary data will be collected.
Following the test, the plant will be returned to nor.al operating conditions.
(2) Although the moderator temperature coefficient will change slightly due to temperature and boron concentration variations, it will not be outside the range of values used in the current 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 accidents initiated during the test will be less severe than indicated on the current safety analyses.
Specifically, the following operating conditions will be adhered to:
o Minimum inlet temperature > 537'F.
o Maximum linear heat rate < 14.2 KW/Ft.
o Pressurizer level will not be varied with the reduced average temperature.
NNECO has determined from the review of the safety analjses that transients and accidents initiated from the lower temperature than previously analyzed will in fact be bounded by the results of the current saf ety analyses.
In addition, the shcrt 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 ques tion ; therefore, pursuant to 10CFR50.90, proposes a license condition included as Attachment 1.
Administrative restrictions which will be in effect during the test will assure that operation will be bounded by analyses and results already approved by the NRC.
The Millstone Unit No. 2 Nuclear Review Board has reviewed and approved this proposed license condition and has concurred in the above determination.
NNECO has reviewed this request pursuant to 10CFR170 and has determined that the request constitutes a Class III amendment. Therefore, please find enclosed the applicable Class III fee in the amount of four thousand dollars ($4,000.00).
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
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W. G. Counsil Vice President At tachment i742 031