ML19347D046
| ML19347D046 | |
| Person / Time | |
|---|---|
| Site: | Maine Yankee |
| Issue date: | 03/06/1981 |
| From: | Randazza J Maine Yankee |
| To: | Harold Denton Office of Nuclear Reactor Regulation |
| References | |
| FMY-81-23, NUDOCS 8103100609 | |
| Download: ML19347D046 (3) | |
Text
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March 6, 1981 FMY-81-23
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United States Nuclear Regulatory Commission
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Washington, D.C.
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Attention: Mr. Harold R. Denton, Director t
Office of Nuclear Reactor Regulation
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Reference:
(a) License No. OPR-36 (Docket No. 50-309) q *.
(b) USNRC Letter dated Novemoer 24, 1980,
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Subject:
Revised Section 10CFR50.46 and New AppenJix R to 10CFR50.
(c) Maine Yankee Letter FMY 81-17, dated February 9, 1981,
Subject:
Request for Exemption
Subject:
Request for Exemption
Dear Sir:
This letter supplements our previous letter on this subject, Ref. (t,).
Maine Yankee Atomic Power Comoany has reviewed the new Section 50.48 and Appendix R to 10CFR50, cealing with fire protection.
During that review, it became S parent.that there are sections that Maine Yankee will be unable to meet.
Therefore, an exemption was requested, Reference (C).
We find it necessary to also request an exemption dealing with the requirement expressed in Section III.L, Alternative and Dedicated Shutdown Capability, paragraphs 3 and 4, reproduced here (emphasis added).
3.
The shutdown capability for specific fire areas may be unique for each su;h area, or it may be one unique combination of systems for all such areas.
In either case, the alternative shutdown capacility snall be indepencent of the specific fire area (s) and shall accommocate postfire conditions where offsite power is available and wnere offsite oower is not available for 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />. Procedures shall be in effect to implement this capaoility.
4.
If the capability to achieve and maintain cold shutdown will not be availaole because of fire damage, the equipment and systems ccmprising the means to acnieve and maintain the hot stancby or hot shutdown conoition shall be capable of maintaining sucn conditions until cold shutdown can be achieved.
If sucn eculoment ano systems will not be caoable of being oowered by notn onsite anc offsite electric power systems oecause of fire cacage, an incepencent onsite power system snall oe proviceo.
Ine numoer of operating shift personnel, exclusive of fire origace memcers, required to coerate such 3quipment and systems shall De on site at all times.
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United States Nuclear Regulatory Ccmmission Page 2 Attention: Mr. Harold R. Denton, Director March 6, 1981 The referenced requirement calls for the plant, using its alternate shutdown capability, to be able to reach and hold hot stanccy conoitions and further, to be able to achieve a cold shutdown condition witnin 72 nours, all without the use of offsite power and assuming the worst case ensite fire.
The alternative shutcown method described by Maine Yankee in previous submittals was not designed to meet this criterion; and ccnsidering the extensive fire protection improvements a-lready made plus the reliacility of our offsite power supply, we do not feel this is a reasonaole design criterion for Maine Yankee to have to meet.
We, therefore, request an exempticn.
The bases for this exemption request are:
First, Maine Yankee has either installed new fire protection systems or improved existing ones In all areas of concern to the NRC during their review of the plant.
In particular, we nave accded sprinkler systems, automated gas suppression systems, increased detection capecility and acced manual fire suppression capability. Because of these improvements, the possiblity of
. losing our onsite power due to fire has been diminished considerably.
In addition, in the areas of previous NRC concern, ne feel that the probability of a fire destroying both onsite and offsite power sources is vanisningly small; ano that we snould not be subject to the arcitrary assumption of a loss of both power sources.
Second, Maine Yankee should not be arbitrarily reOuired to assume a total loss of offsite power for 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> due to a fault cutsice the plant, not associated with a fire. Maine Yankee has an exceptionally reliaole offsite power supply, due_to its redundancy. Maine Yankee has a 115 KV supoly consisting of two lines that feed reserve station service transformers that are capable of supplying all plant power requirements. One line travels north and is supplied by an oil-fired generating station, witn back up from hydro stations further north in the state.
The second 115 KV line runs south and is supplied by another oil-fired generating station, which is cacked up by tie lines into New Hampshire and Massachusetts.
Completely separate from the 115 KV system is.a 4 line 345 KV system which can back-feed the main transformers to supply the unit station service transformers.
The 345 KV distrioution within the state is separate from 115 KV and can_ be fed by one line from New Brunswick in the north, another line from Maine utilities in the east and two other lines frcm New Hampshire and Massachusetts utilities in the soutn. Disconnect links are provided between tne_ generator and the' two main transformers to permit such a' backfeed in an emergency.
The 115 KV transformers are on opposite ends of tne site frcm the 345 KV transformers. Any of these six transmission lines is capable. of supplying all plant power requirements.
We believe wnen the' reliacility of Maine Yankee's offsite poner supply (as described above) is considered along with the inherent reliacility c f the ons'te emergency. bus power supply,'a sound basis is proviced for our request for exemotion from the assumption in Appencix T:na; offsite power is not
-available coincident with-the worst case assumctions rega: ding an onsite fire.
Uniteo States Nuclear Regulatory Commission Page 3 Attention:
Mr. Harold R. Denton, Director Maren 6, 1981 If you have any questions or comments on these requests, please contact us.
We trust that these requests will receive your prompt consicjeration and approval.
Very truly yours, Maine Yankee Atomic Power Company W-eO J. B. Randazza Vice President, Operations JER/plb
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