ML20092A427

Submits Schedule Requested in Re Implementation of Mods Resulting in Scram Discharge Vol Vent & Drain Valve Closure Times Which Meet GE Requirements of 30 S.Tests Will Be Performed to Determine Extent of Mods

ML20092A427
Person / Time
Site:	Hatch
Issue date:	06/14/1984
From:	Gucwa L GEORGIA POWER CO.
To:	Stolz J Office of Nuclear Reactor Regulation
References
NED-84-324, TAC-53327, TAC-53328, NUDOCS 8406190202
Download: ML20092A427 (2)

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Georgu Power Capacy 333 Piedrnont Avenue Atlanta. Georgia 'K)308 Telephone 404 5266526 Mailing Address-Post Office Box 4545 Aitanta, Georgia 30302 Georgia Power L T. Gucwa the soothem eleCIDC system M n ger Nu W r Engeons NED-84-324 and Chief Nuclear Engineer Director of N2 clear Reactor Regulation Attention: Mr. John F. Stolz, Chief Operating Reactors Branch No. 4 Division of Licensing U. S. Maclear Reg 21atory Comuission Washington, D. C. 20555 NHC DOCKEIS 50-121, 50-366 OPERATING LICENSES DPR-57, NPF-5 i EININ I. HAICH NUCLEAR PLANI' UNITS 1, 2 SCRAM DISCHAIEE VOLUME VENI' AND DRAIN VALVE CIOSURE TIMES Gentlemen:

Your letter of May 14, 1984 reglested that Georgia Power Company develop and aabnit to the staff a sched21e for implementation of modifications resaltiry in Scram Discharge Volume (SDV) vent and drain valve closure times which meet the current GE req 11rement of 30 seconds. 'Ihrough an oversight, this modification was not previously inchided in our program of scram discharge system modifications. We hereby provide the reg 2ested information.

As described in our letter of April 23, 1984, tests mast be performed on both Hatch units to determine the extent of modifications necessary to meet this reglirement. The Unit 2 test will be performed & ring the alrrent refueling / pipe replacement outage. '1he Unit 1 test will be performed &rirg the next sche & led refuelirg a2tage, which begins approximately September 1, 1984. The results of these tests will determine wnich of two modification options m2st be enployed for each unit in order to meet the cloaire time reg 2irement. Option 1 involves replacement of the existing pilot solenoids for the SDV vent and drain valves (one solenoid for the vent valves ard one for the drain valves) with q11ck exhaist pilot solenoids. Option 2 involves replacement of the existirg two solenoid design with a six solenoid configuration (indivital solenoids for each of the vent and drain valves) .

'Ite installation schet le will depend upon which option will be regiired. It is currently believed that the referenced tests will show that Unit 2 can meet the reg 2irement with Option 1, while Unit 1, &e to lorger air piping runs, will reg 2 ire implementation of Option 2. Option 1 involves several weeks of design work, and installation co21d be ww-lished in a short period of time (several days) following receipt of design. Option 2 involves a reroute of approximately 3000 feet of conduit and procurement of long lead time materials. Design and procirment times for this option are both on the order of 24 weeks. Installation of Option 2 would reg 2 ire '

approximately 10 weeks, altho 1gh some of the work might be acconplished on 1

line. ,

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-Georgia Power d  ;

' U. S. Maclear Regulatory Coinnission f Director of Maclear Reactor Regulation (

Jane 14, 1984 l Page.2 .

i Based on the- foregoing, we propose the following schedlle: We are  !

expediting design work for Option 1 on Unit 2, based on our belief that Option :1. will be alfficient to allow Unit 2 to acheive the desired cloaire t i % s.. A strong effort will be nude to install- Option 1 prior to startup l from. the current outage. If evahlation ' of. teet re911ts later shows that  ;

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- Option .1_ will not be alfficent, or if unforseen & sign or procurement [

problems comr, we would reglest that the installation of whichever option  !

is reg 11 red for Unit 2 be deferred until the next outage of sufficient ,

diration to complete the modification.  !

. Since it is further expected that Unit l will regtire Option 2 to meet L the clomare time reglirement, we are expediting design ard procureinent_ of [

this' option at the current time. If the upcoming- Unit 1 outage involves  !

recira11ation pipe replacement (airrently under consideration), the Option 2 ,

design will be inplemented in that autage. However, if only a refueling l outage is involved, design and praatrement of Option 2, although already  ;

underway, will not be conplete prior to the end of that autage. In that case, we would propose that the modifications be postponed until the next 7 cutage of alfficient diration following the September, 1984 refueling  ;

outage. If- the rea11ts of the ' Unit 1 test, when performed at the start of ,

the upcoming ' outage, ' indicate that Option 1 is viable, we will couplete installation of that option daring the September,1984, refueling outage.

i We are making every effort to meet the closire ti:ne reglirements on an expeditious basis. However, we contirue . to believe that since no i

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giantitative basis for the reglirement has been demonstrated, contirued

. operation of the Hatch Units with longer cloaire' times represents ~ no j additional risk to the health and safety of the public.

Please' contact this office if further information is desired in this }

regard.

Very truly yours, {

/

fhfa~bu l pfu L. T. G1 cwa REB /

xc: H. C. Nix, Jr.  !

J. P. O'Reilly (NRC-RII) l Senior Resident Inspector, Plant Hatch  !

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