ML19345B649
| ML19345B649 | |
| Person / Time | |
|---|---|
| Site: | Maine Yankee |
| Issue date: | 11/21/1980 |
| From: | Garrity J Maine Yankee |
| To: | Eisenhut D Office of Nuclear Reactor Regulation |
| References | |
| TASK-2.K.3.30, TASK-TM JHG-80-106, WMY-80-153, NUDOCS 8012020288 | |
| Download: ML19345B649 (2) | |
Text
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,. v EDISON DRIVE MAIRE BRRHEE ATomICPOWERCOMPARU*
avaugra, ya,ng osass E7 (207)623-3521
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C November 21, 1980 u
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JHG-80-106 O
WMY 80-153 ui Q
B.3.2.1 F.
United States Nuclear Regulatory Commission Washington, D. C.
20555 Attention:
Office of Nuclear Reactor Regulation Mr. Darrell G. Eisenhut, Director Division of Licensing
References:
(a)
License No. DPR-36 (Docket No. 50-309)
(b)
USNRC Letter to All Licensees of Operating Plants, dated October 31, 1980 (c) Maine Yankee letter to USNRC dated July 30, 1980
Subject:
LOFT Small Break Test L3-6 Prediction Requirements (WMY 80-114)
Subject:
NRC Action Plan Item II.K.3.30; Revised Small Break LOCA Methods.
Dear dir:
The Bulletins and Orders Task Force review of the emergency core cooling system modeling methods used by the industry identified a number of concerns regarding the adequacy of these methods.
We have very carefully reviewed the documentation of these concerns. A few may be applicable to the model licensed for use in analyzing small break LOCA's at Maine Yankee.
Action plan item II.K.3.30 sets forth the current requirements for resolving these concerns by providing the necessary assurance that small break LOCA models are acceptable. This assurance can be provided by either model revision or alternatively by additional justification of the currently licensed model by comparison with appro-priate test data.
This letter indicates the scope and schedule of the program to be pursued in resolving ECCS model concerns with respect to Maine Yankee.
Two parallel approaches are being pursued. These approaches are continuations and extensions of the work described in ref. (c).
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MAINK YANKEE ATOMIC POWER CIMPANY PAGE JHG-80-106 In brief, one approach involves revision of the current RELAP 4 mod 3 EM based Maine Yankee small break LOCA model, the other involves development of a Maine Yankee model based on RELAP 5 which would eventually be licensed for EM work and also used in BE mode for engineering applications.
Ref. (c) indicated these two parallel paths would be pursued through IDFT L3-6 test analysis. Analysis of LOFT L3-1 and L3-5 tests are now also being included in the program leading to a final decision on which approach is better.
We expect that a decision on which of the two approaches is the better will be made by February 15, 1981. At that time, efforts on the other will be curtailed. Following that decision, we will address and resolve the following issues:
(1) Code assessment using available SB integral tests (2)
Code ability to predict natural circulation (3)
Treatment of thermodynamic non-equilibrium (4) Treatment of non-condensibles (5) verification of high pressure, two-phase discharge data Data from the LOFT SB test series, EPRI relief valve program and plant natural circulation tests may be utilized to resolve some of these issues. Other tests being performed by the industry will also be assessed for their relevance to the verification and qualification task at hand.
We believe that the modeling effort will be completed by January 1, 1982. We will be available to discuss our verification and qualification plans with you any time after February 15, 1981.
We trust this information is satisfactory; however, should you have any questions, please contact us.
Very truly yours, MAINE YANKEE ATOMIC POWER COMPANY TUG John H. Garrity, Director Nuclear Engineering and Licensing JHG/bjp
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