ML20214L796
| ML20214L796 | |
| Person / Time | |
|---|---|
| Site: | Millstone  |
| Issue date: | 05/26/1987 |
| From: | Mroczka E NORTHEAST NUCLEAR ENERGY CO., NORTHEAST UTILITIES |
| To: | NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM) |
| Shared Package | |
| ML20214L799 | List: |
| References | |
| TASK-08-03.B, TASK-8-3.B, TASK-RR B12228, NUDOCS 8706010080 | |
| Download: ML20214L796 (3) | |
Text
,
4 c.
N t#TILITIES o.nerai On,c.. s.ioen sir... seriin. connecticui
.$T.
I,$[.$[Ia$
P O. BOX 270 w....n."*""
HARTFORD. CONNECTICUT 06141-0270 k
k J C'.U $[.'.[,[,
(203) 665-5000 May 26,1987 Docket No. 50-245 B12228 Re: 10CFR50.90 U.S. Nuclear Regulatory Commission Attn Document Control Desk Washington, D.C. 20555 Gentlemen Millstone Nuclear Power Station, Unit No.1 Proposed Revision to Technical Specifications DC Power Availability Pursuant to 10CFR50.90, Northeast Nuclear Energy Company (NNECO) hereby proposes to amend its Operating License No. DPR-21 by incorporating the changes identified in Attachment 1 into the Technical Specifications of Millstone Unit No.1.
SEP Topic VIII-3.B, "DC Power System Bus Voltage Monitoring and Annunciation," identified that the Millstone Unit No.1 Technical Specifications allow for a seven-day outage time of one of the two 125 volt DC or 24 volt DC battery systems. The NRC stated in NUREG-0324 (Integrated Plant Safety Assessment for Millstone Unit No.1) that a !!mited probabilistic risk assessment concluded that a 50 percent reduction in the Technical Specification allowed outage time for these batteries could reduce the core-melt frequency by 0.6 percent.
The NRC recommended that NNECO propose to reduce the allowable outage time or justify the present battery outage limits.
The proposed change will revise Technical Specification 3.9.B.5, and its corresponding Bases, by reducing the allowable outage time from 7 days to 24 ho'srs (with the restriction to be in cold shutdown in the next 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />) which is more conservative than the 50 percent reduction in allowabic outage time recommended by the NRC, but longer than the BWR Standard Technical Specification battery outage time of two hours. The change will also reduce the probability of core melt.
The following justification for proposing a 24-hour allowable outage time instead of adopting the Standard Technical Specification is provided:
1.
A two-hour allowable outage time allows for an orderly shutdown only.
0706010000 070526 h
DR ADOCK 0D00 5
cfW h /L N T
r U.S. Nucl:ar Regulatory Commission B12228/Page 2 May 26,1987 2.
Twenty-four hours allows for evaluation of the battery system problem and allows for minor repairs; e.g., output breaker repair.
3.
Unwarranted shutdowns could be avoided, thus reducing the number of thermal cyc!cs to which the plant is subjected.
NNECO has reviewed the attached proposed changes pursuant to 10CFR50.59 and has determined that they do not constitute an unreviewed safety question.
The probability of occurrence or the consequences of an accident or malfunction of equipment important to safety (i.e., safety-related) previously evaluated in the Final Safety Analysis Report (FSAR) have not been increased.
The possibility for an accident or malfunction of a different type than any evaluated previously in the FSAR has not been created. There has not been a reduction in the margin of safety as defined in the basis for any Technical Specification.
These proposed changes will not result in physical changes to the plant or changes in the way the plant is operated.
NNECO has reviewed the proposed changes in accordance with 10CFR50.92 and has concluded that they do not involve a significant hazards consideration in that these changes would not:
1.
Involve a significant increase in the probability or consequences of an accident previously evaluated. This change continues to provide repair time while significantly reducing the period of time a battery may be out of service.
2.
Create the possibility of a new or different kind of accident from any previously analyzed in the FSAR.
The change will not introduce new failure modes.
3.
Involve a significant reduction in a margin of safety. By reducing the allowable outage time, the margin of safety is increased.
The Commission has provided guidance concerning the application of standards in 10CFR50.92 by providing certain examples (31FR7751, March 6,1986).
The changes proposed herein are enveloped by example (11), a change that constitutes an additional limitation, restriction, or control not presently included in the Technical Specifications; e.g., a more stringent surveillance requirement. The proposed change reduces the previously permissible outage period from 7 days to 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.
The Millstone Unit No. I Nuclear Review Board has reviewed and approved the l
attached proposed revisions and has concurred with the above determinations.
l In accordance with 10CFR50.91(b), we are providing the state of Connecticut with a copy of these proposed amendments.
!L
o i
U.S. Nuclear Regulatory Commission B12223/Page 3 May 26,1987 Pursuant to the requirements of 10CFR170.12(c), enclosed with this amendment request is the~ application fee of $150.
s Very truly yours, NORTHEAST NUCLEAR ENERGY COMPANY A
E.33)foczka
/~
Senio(Vice President Enclosure cc:
Kevin McCarthy Director, Radiation Control Unit Department of Environmental Protection Hartford, Connecticut 06116 W. T. Russell, Region 1 Administrator J. J. Shea, NRC Project Manager, Millstone Unit No.1 T. Rebelowski, Resident inspector, Millstone Unit No.1 STATE OF CONNECTICUT)
) ss. Berlin COUNTY OF HARTFORD )
Then personally appeared before me, E. J. Mroczka, 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 Licensee herein and that the statements contained in said information are true and correct to the best of his knowledge and belief, hhAt nE Nbtary Publi
~
}nt V My Commiss;on Expnes March 31,1988