ML20099C378
| ML20099C378 | |
| Person / Time | |
|---|---|
| Site: | Hatch  |
| Issue date: | 11/06/1984 |
| From: | Gucwa L GEORGIA POWER CO. |
| To: | Stolz J Office of Nuclear Reactor Regulation |
| References | |
| NED-84-578, TAC-55695, NUDOCS 8411190508 | |
| Download: ML20099C378 (3) | |
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Georgia Power Company 333 Piecnont Avenue Atlanta, Georgia 30308 j
Telephore 404 5266526 Maihng Address-Post Ottce Box 4545 A!!anta. Georgia 30302 Georgia Power L T. Gucwa tre sa:rm eittlic sys:cm Manager Nuclear Engeeenng and Chief Nuclear Engreer NED-84-578 November 6, 1984 Director of M1 clear Reactor Reg.11ation Attention: Mr. John F. Stolz, Chief Operating Reactors Branch No. 4 Division of Licensing U. S. Nuclear Regulatory Comnission Washington, D. C.
20555 NRC DOGET 50-321 OPERATING LICENSE DPR-57 EDWIN I. HATCH NUCLEAR PLANT UNIT 1 REVISION OF PREVIOUS HPCI PRGSURE TRIP TEQiNICAL SPECIFICATION CHANGE PROIOSAL FOR ATIS Gentlemen:
By letter dated October 18, 1984 (NED-84-539) Georgia Power Conpany (GPC) mtnitted revisions to the Analog Transmitter Trip System (ATIS)
Technical Specification change proposed by our letter dated September 5,
1984 (NED-84-436).
These revisions added proposed changes for two High Presm re (bolant Injection (HPCI)
System Steam Line High Differential Presm re trip instruments (E41-N657 A, B) which were added to the ATIS installation scope following mbmittal of car September 5,1984 letter.
Ute contents of one of the non-Technical Specification pages enc]osed with our October 18, 1984 letter does not ccepletely describe the prccess used to arrive at the instrument setpoint.
In particular, the applicability of Regulatory Glide 1.105 needed clarification.
Therefore, GPC has rewritten that particular page to prevent any confusion regarding the basis or the intent of the proposed change. The new revised page (No. 4-28a) is enclosed with this letter and should be used in place of the page of the same rumber which was enclosed with cur October 18, 1984 letter.
This latest revision does not directly affect any of the proposed changed Technical Specification pages which GPC has previously stuitted.
R1rthermore, the safety evaluations and significant hazard reviews stritted by the above-referenced letters are unaffected by this revision.
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Georgialbwer d Director of Nuclear Reactor Regulation Attention: Mr. John F. Stolz, Chief Operating Reactors Branch No. 4 Noveinber 6,1984 Page 'IW should you have any 4:estions, please contact this office.
Very truly yours, 0(fW L. T. Gicwa y
CBS/inb xc:
J. T. Beckham, Jr.
H. C. Nix, Jr.
J. P. O'Reilly (NRC-Region II)
Senior Resident Inspector
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HFCI steam line differential presaire - high (E41-N657A,B)
%e purpose of this instrumentation is to detect HPCI steam line breaks and to isolate any alch break to confine the rea11 ting radioactivity release and limit tie reactor inventory loss. %e HEIB analysis asalmes that the HPCI turbine trips and the system isolates at 300 percent ~of rated flow.
However, the HEIB analysis is used for gaillotine breaks which have flows several times higher than 300 percent of rated flow.
Initially, the setpoints were derived for this trip function using an analytical limit of 300 percent of rated flow using Regulatory Glide 1.105.
%e rea11 ting setpoints resulted in an operability concern for GPC clie to past experience with the HPCI system at Plant Hatch.
Since the setpoints currently being used by tie plant were historically known to provide for satisfactory system operation, a required analytical limit was derived from the Plant Hatch existing setpoints using Regulatory Glide 1.105 methodology.
%is analytical limit was 307 percent of rated flow.
An analysis was performed to asaire the acceptability of tre new analytical limit (307 percent of rated flow).
It was determined that for extremely large breaks, the operation of this trip function is almost instantaneous and the difference in isolation time between 300 percent and 307 percent of rated flow is negligible.
For smaller breaks wbere there may be a noticeable difference in time clie to the new analytical limit, the leakage detection system (which is the primary protection for smaller breaks) still would provide adecanate isolation with less inventory loss and less peak room temperature than the inventory loss and peak room tenperature predicted in the HEIB cpillotine break case.
Using this technicale, an allowable value of 303 percent of rated flow was developed.
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