ML20134E082

Advises That Ambiguous Statement in 840713 Safety Evaluation Re Amend 39 to License NPF-5,concerning Aprm/Rod Block Monitor Tech Spec Improvement Program,Has No Effect on Conclusions of Evaluation

ML20134E082
Person / Time
Site:	Hatch
Issue date:	08/12/1985
From:	Stolz J Office of Nuclear Reactor Regulation
To:	Beckham J GEORGIA POWER CO.
References
TAC-54433, TAC-54607, NUDOCS 8508190605
Download: ML20134E082 (2)

Text

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~ ' August 12, 1985 3% Oby Dockets Nos. 50-321 D_ISTRIBUTION and 50-366 CDocket File.) BGrimes NRC PDR JPartlow L PDR -

ACRS-10 ORBf4 Rdg RIngram Mr. J. T. Beckham, Jr. HThompson GRivenbark Vice President - Nuclear Generation OELD Gray File Georgia Power Company EJordan l P. O. Box 4545 l Atlanta, Georgia 30302 l

Dear Mr. Beckham:

It has recently come to our attention that the Safety Evaluation that we enclosed with cur letter to you dated July 13, 1984 transmitting amendment No. 39 to the Hatch Unit 2 operating license contains a statement concerning the Hatch average Power Range Monitor / Rod Riock Monitor Technical Specification (ARTS) Improvement Program that is ambiguous. The statement

! occurs in the first paragraph of Section 2.6.1 of the report and is "The effect is to allow operation at 100 percent power for greater than 87 percent flow and to increase the permitted power at 40 percent flow by about 5 percent to 63.2 percent". The ambiguity concerns whether the flow referred to is total core flow or recirculation flow. It should be core flow in which case the permitted power at 40 percent flew is 67 percent rather than 63.2 per-cent. The minimum flow at 100 percent power (87 percent) is correct. The concern in the low flow area has to do with core thermal-hydraulic stability.

Higher power at low flow reduces the margin to instability. However, the stability analysis was performed with the correct assumptions for core power and flow and resulted in a decay ratio less than unity at the least stable point in the power / flow map. Further, Georgia Power Company has comitted to follow the recomendations of GE Service Information Letter Number 380 which requires monitoring local cnd average power instrumentation in order to avoid unstable operation.

Based on the above discussion, we conclude that the ambiguous statement in the evaluation of the Hatch ARTS program has no effect on the conclusions of that evaluation.

Sincerely,

'o?.Icimu, :;1cu!.D id Jgt:i y. S1%4' John F. Stolz, Chief Operating Reactors Branch #4 Division of Licensing cc: See next page ORB L OR :DL GRivenbark;cr JS 8/j/85 8/

l 8508190605 050012 PDR ADOCK 05000366 P PDR

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Mr. J. T. Beckham, Jr. Edwin I. Hatch Nuclear Plant, Georgia Power Company Units Nos. I and 2 CC:

G. F. Trowbridge, Esq.

Shaw, Pittman, Potts and Trowbridge 1800 M Street, N.W.

Washington, D.C. 20036 Mr. L. T. Gucwa Engineering Department Georgia Power Company P. O. Box 4545 Atlanta, Georgia 30302 Mr. H. C. Nix, Jr., General Manager Edwin I. Hatch Nuclear Plant Georgia Power Company i P. O. Box 442 i Baxley, Georgia 31513 I Mr. Louis B. Long

> Southern Company Services, Inc.

P. O. Box 2625

Birmingham, Alabama 35202 Resident Inspector '

U.S. Nuclear Regulatory Commission Route 1, P. O. Box 279 Baxley, Georgia 31513

! Regional Administrator, Regior II U.S. Nuclear Regulatory Commission, 101 Marietta Street, Suite 3100 i

Atlanta, Georiga 30303 Mr. Charles H. Badger Office of Planning and Budget Room 610 4 270 Washington Street, S.W.

Atlanta, Georgia 30334 Mr. J. Leonard Ledbetter, Comissioner Department of Natural Resources 270 Washington Street, N.W.

Atlanta, Georgia 30334 Chairman

Appling County Comissioners County Courthouse Baxley, Georgia 31513

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