ML20248M038

Forwards Request for Addl Info Re Revised Loop Stop Valve Operation.Changes Will Modify Requirements for Isolated Loop Startup to Permit Filling of Drained Isolated Loop Via Backfill from RCS Through Partially Opened Loop Stop Valves

ML20248M038
Person / Time
Site:	North Anna
Issue date:	06/09/1998
From:	Kalyanam N NRC (Affiliation Not Assigned)
To:	Ohanlon J VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.)
References
TAC-M97187, TAC-M97188, NUDOCS 9806120281
Download: ML20248M038 (3)

Text

_ _ _ _ _ _ _ _ _

June 9, 1998 Mr. J. P. O'Hanlon Senior Vice President - Nuclear Virginia Electric and Power Company 5000 Dominion Boulevard l

Glen Allen, VA 23060

SUBJECT:

REQUEST FOR ADDITIONAL INFORMATION - REVISED LOOP STOP VALVE OPERATION: NORTH ANNA POWER STATION, UNITS 1 AND 2 (TAC NOS.

M97187 AND M97188)

Dear Mr. O'Hanlon:

On November 6,1997, Virginia. Electric and Power Company requested changes which will modify the requirements for isolated loop startup to permit filling of a drained isolated loop via backTill from the Reactor Coolant System through partially opened loop stop valves. By letter of March 16,1998, the staff requested additionalinformation and your response was provided by your letter of April 15,1998.

The NRC staff is reviewing and evaluating your request. The enclosure contains an additional set of questions from the staff in order to complete its review. We request that you respond within 30 days.

Sincerely, (Original Signed By)

N. Kalyanam, Project I,Mnager Project Directorate Il-1 Division of Reactor Projects - 1/11 Office of Nuclear Reactor Regulation Docket Nos. 50-338 and 50-339

Enclosure:

Request for Additional

/

Information 7

cc w/ encl: See next page DISTRIBUTION-

/

C

. P isco, R 11 ACRS J. Zwolinski n

b' FILENAME - G:\\NOANNA\\M97187-1.

I OFFICE PM:PDil-1 LA:PDil-1 D:PDil-1 n,([h NAME NKalyanam M EDunnington $

PTKuo [I DATE b / 7/98 4/ f/98 h/0 /98 COPY No (fedho Yes/fdo 9006120291 900609 PDR ADOCK 05000338 P

PDR 3

Mr. J. P. O'Hanlon North Anna Power Station Virginia Electric & Power Company Units 1 and 2 cc:

Mr. J. Jeffrey Lunsford Regional Administrator, Region 11 County Administrator U.S. Nuclear Regulatory Commission Louisa County Atlanta Federal Center P.O. Box 160 61 Forsyth St., SW, Suite 23T85 Louisa, Virginia 23093 Atlanta, Georgia 30303 Michae! W. Maupin, Esquire Mr. W. R. Matthews, Manager Hunton and Williams North Anna Power Station Riverfront Diaza, East Tower P. O. Box 402 951 E. Byri Street Mineral, Virginia 23117 Richmond, Virginia 23219 Mr. R. C. Haag Dr. W. T. Lough U.S. Nuclear Regulatory Commission Virginia State Corpora + ion Atlanta Federal Center Commission

~

61 Forsyth St., SW, Suite 23T85 Division of Energy Regulation Atlanta, Georgia 30303 P. O. Box 1197 Richmond, Virginia 23209 Mr. David Christian, Manager Surry Power Station Old Dominion Electric Cooperative Virginia Electric and Power Company 4201 Dominion Blvd.

5570 Hog Island Road Glen Allen, Virginia 23060 Surry, Virginia 23883 Mr. J. H. McCarthy, Manager Robert B. Strobe, M.D., M.P.H.

Nuclear Licensing & Operations State Health Commissioner Support Office of the Commissioner Virginia Electric and Power Company Virginia Department of Health Innsbrook Technical Center P.O. Box 2448 5000 Dominion Blvd.

Richmond, Virginia 23218 Glen Allen, Virginia 23060 Office of the Attorney General Commonwealth of Virginia 900 East Main Street Richmond, Virginia 23219 Senior Resident inspector North Anna Power Station U.S. Nuclear Regulatory Commission 1024 Haley Drive Mineral, Virginia 23117

VIRGINIA ELECTRIC AND POWER COMPANY NORTH ANNA POWER STATION. UNITS 1 AND 2 l

SUPPLEMENTAL REQUEST FOR ADDITIONAL INFORMATION l

REGARDING REVISED LOOP STOP VALVE OPERATION TAC NOS. M97187 AND M97188 1.

The response to questions 3 and 4 from the original set of RAls, dated April 14,1998, indicates that the loop stop valves will not be opened with any of the reactor coolant pumps (RCPs) operating and the analyses assume free convection rather than forced convection, associated with RCP operation. The basis provided to justify no RCP pump j

operation is that the design differential pressure for the loop stops valves is only 200 psi j

and the RCP seals require 300-325 psi to operate properly. The set of initial conditions where this evolution can be accomplished safely should not be derived solely from the design limitations on the individual components but rather should be established in the l

Technical Specifications allowing the evolution. As a result, if opening a loop stop valve I

can only be accomplished safely with no RCPs running and RCP operation is permitted in mode 5 where the specification applies, the specification should be modified to preclude RCP operation.

2.

Question 5 from the original RAI requested a description of how the gas from the empty i

isolated loop was vented. Please provide this description.

3.

The response to question 6 indicates that level instrument uncertainties are not included in the 450 ft8 specification and that no channel uncertainty has been calculated because of the conservatism in the analysis. Although there is a good deal of conservatism in the analysis, using this conservatism to bound the instrument uncertainties is not appropriate because neither the conservatism nor the instrument uncertainty has been quantified. Please include instrument uncertainties in the development of the pressurizer water volume specifica: on.

1