AECM-86-0163, Provides Addl Info to 860321 Proposed Change PCOL-86/04 to License NPF-29 Re Mods to Automatic Depressurization Sys Per BWR Owners Group Evaluation of NUREG-0737,Item II.K.3.18. Info Clarifies Changes Made to Sys Initiation Circuitry

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Provides Addl Info to 860321 Proposed Change PCOL-86/04 to License NPF-29 Re Mods to Automatic Depressurization Sys Per BWR Owners Group Evaluation of NUREG-0737,Item II.K.3.18. Info Clarifies Changes Made to Sys Initiation Circuitry
ML20198N327
Person / Time
Site: Grand Gulf Entergy icon.png
Issue date: 05/30/1986
From: Kingsley O
MISSISSIPPI POWER & LIGHT CO.
To: Harold Denton
Office of Nuclear Reactor Regulation
References
RTR-NUREG-0737, RTR-NUREG-737, TASK-2.K.3.18, TASK-TM AECM-86-0163, AECM-86-163, TAC-61039, NUDOCS 8606060048
Download: ML20198N327 (2)


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MISSISSIPPI POWER & LIGHT COMPANY

] Helping Build Mississippi Eull&liddiddE P. O. B O X 16 4 0. J A C K S O N. MISSISSIPPI 39215-1640 May 30, 1986 O. D. KINGSLEY, JR.

vaCE PRESIDENT - NUCLEAR OPERAYiONS U. S. Nuclear Regulatory Commission Office of Nuclear Reactor Regulation Washington, D. C. 20555 Attention: Mr. Harold R. Denton, Director

Dear Mr. Denton:

SUBJECT:

Grand Gulf Nuclear Station Unit 1 Docket No. 50-416 License No. NPF-29 Additional Information PCOL-86/04 AECM-86/0163 Mississippi Power & Light (MP&L) Company submitted a proposed char.ge to Facility Operating License NPF-29 in a letter from Mr. O. D. Kingsley, Jr. to Mr. Harold R. Denton dated March 21, 1986. Item 3 of the March 21, 1986 letter proposed changes to the technical specifications needed to implement modifications to the Automatic Depressurization System (ADS) in accordance with Option 4 of the BWR Owners' Group evaluation of NUREG-0737, Item II.K.3.18 (License Condition 2.C(33)(f)).

In the justification section for the proposed technical specification changes, MP&L stated that once the bypass timer times out, the bypassing of the high drywell pressure would be sealed in and the bypass timer would not automatically reset. This statement concerning the proposed design was correct at the time of the March 21, 1986 letter. However, recent modifications to this design by General Electric will result in the removal of this seal-in so that once the RPV level is recovered above Level 1, the bypass timer is reset and, in the event the ECCS Pumps are tripped, the logic is completely reset to terminate the automatic initiation of ADS. This change is an enhancement to the originally proposed design and is being made to help prevent inadvertent automatic ADS initiations after the first ADS initiation. This change to the ADS system does not affect the proposed changes to the technical specifications in the March 21, 1986 letter but is being provided to clarify the changes being made to the ADS initiation circuitry.

If there are any questions, feel free to contact this office.

Yours ly, 8606060048 860530 o PDR ADOCK 0500

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Page 2 cc: Mr. T. H. Cloninger Mr. R. B. McGehee Mr. N. S. Reynolds Mr. H. L. Thomas Mr. R. C. Butcher Mr. James M. Taylor, Director Office of Inspection & Enforcement U. S. Nuclear Regulatory Commission Washington, D. C. 20555 Dr. J. Nelson Grace, Regional Administrator U. S. Nuclear Regulatory Commission Region II 101 Marietta St., N. W., Suite 2900 Atlanta, Georgia 30323 J10AECM86052701A - 2