ML19209A498
| ML19209A498 | |
| Person / Time | |
|---|---|
| Site: | Maine Yankee |
| Issue date: | 09/27/1979 |
| From: | Vandenburgh D Maine Yankee |
| To: | Office of Nuclear Reactor Regulation |
| References | |
| WMY-79-107, NUDOCS 7910040255 | |
| Download: ML19209A498 (2) | |
Text
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B.3.2.1 KMY 79-107 MAIRE HARHEE
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TURNPIKE ROAD (RT. 9)
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ENGINEERING OFFICE WEST 80aO. MASSACHUSETTS 01581
's 617-366-9011
" w gg September 27, 1979 United States Nuclear Regulatory Commission Washington, D. C.
20555 Attention: Office of Nuclear Reactor Regulation
References:
(a) License No. DPR-36 (Docket No. 50-309)
(b) USNRC letter to MYAPC dated January 25, 1978 (c) MYAPCo Letter to USNRC dated July 23, 1979
Dear Sir:
Subj ect: Maine Yankee Asy= metrical LOCA Loads Evaluation The purpose of this letter is to update our last letter (Reference (c))
concerning our evaluation of the asymmetrical LOCA loading issue.
Postulated Breaks Inside the Reactor Vessel Cavity Maine Yankee has awarded a contract to EDS Nuclear Services to perform a feasibility study of installing cold and hot leg pipe restraints in order to limit the postulated break size hence reducing the consequences of the asymmetric loads. During our recent outage, "as built" dimensions were taken in order to insure proper design data. Maine Yankee will receive a design re-port by the end of the first week in October. The resulting break open area will be used to generate LOCA loads which will be input for the structural analysis of the vessel structures.
Maine Yankee plans to hold a meeting with the NRC to discuss the results of the EDS design study and additional analyses required for resolution of the asymmetrical loading issue for breaks postulated inside the reactor vessel cavity.
If an agreement is reached betweet. the NIC and Maine Yankee as to the extent of additional analyses required, the pipe restraints would be installed as soon as practical. At the present time the target date would be the upcoming refueling outage in early 1980.
Postulated Breaks Outside the Reactor Vessel Cavity Maine Yankee's approach from the beginning has been to first assure the adequacy of the vessel support structures since our preliminary scoping studies have indicated this to be the area which is most effected by asymmetrical loading. Both Combustion Engineering and Westins, house in Maine general, have proven this premise for their respective owner groups.
Yankee has begun a study to ccmpare our subcompartment geometry, postulated mass energy release and structural responses to plants which have shown structural adequacy with the additional asymmetrical loads. With this data Maine Yankee will demonstrate through conservative comparisons the structural DT 1090 062 791oo4o us
United States Nuclear Regulatory Commission September 27, 1979 Attention: Office of Nuclear Reactor Regulation Page Two integrity of the supports and structures. This effort should be completed by the beginning of 1980. A report will be submitted to the NRC shortly thereafter.
The NRC notified Maine Yankee in January 1978, Reference (b), that a two year completion date was required to resolve the asymmetric LOCA loads issue.
The approach that we have taken will enable us to satisfy that requirement.
During a meeting in October we will present our schedule which we believe will resolve the asym =etrical loading problem for Maine Yankee by the end of January 1980.
If any questions arise, please feel free to call us at our office (617) 366-9011.
Very truly yours, MAINE YANKEE ATOMIC POWER COMPANY D. E. Vandenburgh Vice President TMC/scv 10'10 063