ML19312D349

Forwards Request for Addl Info Re Adequacy of Station Electric Distribution Sys Voltage to Complete Review of

ML19312D349
Person / Time
Site:	Hatch
Issue date:	02/29/1980
From:	Ippolito T Office of Nuclear Reactor Regulation
To:	Whitmer C GEORGIA POWER CO.
References
TAC-10026, TAC-12831, TAC-12832, TAC-47044, NUDOCS 8003240250
Download: ML19312D349 (4)

Text

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't, *.... #' February 29, 1980 Docket Nos. 50-321 and 50-366 Mr. Charles F. Whitmer Vice President - Engineering Georgia Power Company P. O. Box 4545 Atlanta, Georgia 30302

Dear Mr. Whitmer:

We have completed our review of your submittal dated December 7,1979 regarding the adequacy of station electric distribution system voltage at Edwin I. Hatch Nuclear Plant Units 1 and 2. In the course of our review we have determined that the additional infomation identified in the enclosure is required. We request that the additional information be submitted within 45 days of your receipt of this letter. Sincerely, dhM Thomas e f Ippolito, Chief Operating Reactors Branch #3 Division of Operating Reactors

Enclosure:

Request for Additional Infomation cc w/ enc 1: See next page 8003240 2 N p i 1

Mr. Charles F. Whitmer Georgia Power Conpany cc: G. F. Trowbridge, Esquire Shaw,-Pittman, Potts and Trowbridge 1800 M Street, N. W. Washington, D. C. 20036 Ruble A. Thomas Vice President P. O. Box 2625 Southern Services, Inc. Birmingham, Alabama 35202 Ozen Batum P. O. Box 2625 Southern Services, Inc. . Birmingham, ~ Alabama 35202-Mr. William Widner Georgia Power Company Power Generation Department - P. O. Box 4545 Atlanta, Georgia 30302 Mr. L.- T. Gucwa ~ -Georgia Power Company ' Engineering Department P. O. Box 4545 Atlanta, Georgia 30302 Appling County Public Library Parker Street-Baxley, Gecrgia 31413 Mr. R. F. Rogers U. S. Nuclear. Regulatory Commission P. O. Box 710 Baxley, Georgia l31513 t.

s HATCH 1 AND 2 (DOCKET NOS. 50-321 AND 50-366) QUESTIONS ON DEGRADED GRID, PART B Referencess .GeorgiaPower(GP) letter (R.J.(elly)toNRC,"AdequacyofStation a. Electric Distribution System Voltages," dated December 7,1979. b. NRC generic letter to all Power Reactor Licensees, " Adequacy of Sta-tion Elcetric Distribution System Voltage," dated August 8,1979. ~ Questions: 1. Reference a does not define the minimum and maximum anticipated grid b -voltages. Guideline 6 allows three methods of determining the value of the degraded. grid voltage, whichever provides the worse case. GP should describe how their grid voltage levels are determined (one method may produce the low voltage while another method may produce the high voltage) and state what these velues are. 2. Supply the calculated voltages for all low voltage AC (less than 600 V) class 1E buses for each analyzed case. Do these systems supply any instruments and control circuits as required by CDC 137 If so, is all equipment capable of sustaining the analyzed voltages (blowing fuses, overheating, etc.)? Is the connected equipment qualified by the manu-facturers to withstand the expected voltages without affecting their { ability to perform the required function? 3. What are the voltages and duration on all class 1E buses when starting and running a 7000-HP reactor re-cire M-G set? Justify continued operation of the class 1E loads for this duration and describe how spurious trips of the class IE buses and loads are prevented during this time period. The intent of NRC guidelir.3 3 was that during tha. worst case (LOCA) loading conditions constderation should be made 'for any possible start of a large non-safety load. The analysis would then show the r'esultant voltages for all safety-related loads (buses) 1

t. during the transient (start) and the steady state (running) stages. The voltage on the other buses should be provided for the transient and steady state stages. ' 4-440AT ARE THE Ses LAV. 2Gl.g settings and time delays? ill spurious tripping of safety loads occur during analyzed conditions? This is b requested per guidelines 8,10, and 12, Ji. Is it possible that the units' unf t auxiliary transformers would sup-ply the class IE load group? If nothing prohibits such a connection, this analysis should be performed as guideline 1 requires. d. Figures 15 and 16 compare the calculated voltages with the McASURED 8 voltages for the 4160 V buses. They do not verify the accuracy of the calculations for the 600 V AC and lower voltage buses. GP.should provide. test procedure and test results as required by reference b. Jf. ' Reference a establishes a possible scenario which could result in unacceptable voltages. The attachments to reference a identify sev- .eral possible corrective measures, yet reference a does not co==it to b corrective action. Per guideline 9, GP must inform the NRC of the immediate remedial action that has been taken. 8. Figures 7 and 14" do not show what the resultant bus voltages are on the 600 V buses (and lower voltage buses).. Duration of this motor starting transient are. not identified. GP should verify that the other class IE buses and loads are not being subjected to undervoltage ~ D problems resulting from this transient. condition, per guideline 9. l L '2 'NI e ~ j n.- ,.m-' =}}