ML20216G424
| ML20216G424 | |
| Person / Time | |
|---|---|
| Site: | North Anna  |
| Issue date: | 03/16/1998 |
| From: | Kalyanam N NRC (Affiliation Not Assigned) |
| To: | Ohanlon J VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.) |
| References | |
| TAC-M97187, TAC-M97188, NUDOCS 9803190402 | |
| Download: ML20216G424 (3) | |
Text
3 March'16, 1998
-e Mr. J. P. O'Hanlon Senior Vice President - Nuclear Virginia Electric and Power Company 5000 Dominion Boulevard Glen Allen,VA 23060
SUBJECT:
REQUEST FOR ADDITIONAL INFORMATION - REVISED LOOP STOP VALVE OPERATION; NORTH ANNA POWER STATION, UNO 1 AND 2 (TAC i40S.
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 backfill from the Reactor Coolant System through partially opened loop stop valves.
The NRC staff is reviewing and evaluating your request. Additionalinformation, as discussed in the enclosure, is requested in order for the staff to complete its review. We request that you respond within 30 days.
Sincerely, (Original Signed By)
H. Kalyanam, Project Manager Project Directorate 11-1 Division of Reactor Projects - 1/II Office of Nuclear Reactor Regulation Docket Nos. 50-338 and 50-339
Enclosure:
Request for Additional Information cc w/ enclosure:
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-lr REQUEST FOR ADDITIONAL INFORMATION REGARDING REVISED LOOP STOP VALVE OPERATION NORTH ANNA POWF.R STATION, UNITS 1 AND 2 (TAC NOS. M97187 AND M97188) i (1)
How are the loops verified to be drained prior to opening the loop isolation valves?
(2)-
What is the maximum allowed leakage into an isolated loop from the RCS and the SGs (i.e.,
permitted loop stop valve leakage and allowable leakage from the secondary side through leaking SG tubes) over the two hours between verifying the loops are drained and opening the loop stop valves? What is the effect of this potentially unborated water on the shutdown margin?
(3)'
There are no limitations on the RCS temperature or pressures, other than being in Modes 5 or 6. Please describe the safety impacts of opening the isolation valves at the temperature and pressure extremes allowed by the current TS. If openlag the valves at the extremes is not permitted or analyzed please clarify proposed specification 3.4.1.6.a to further limit this evolution.
(4)
If the SG secondary side is at a much higher or lower temperature than the RCS, how much will the overall RCS temperature change when the stop valves are opened (i.e., can the SGs act as a heat source or heat sink)? Please be sure to consider if one or more of the other loops are in service with an RCP running. What is the effect of this potential temperature change on the shutdown margin?
(5) is there any potential that the gas volume in the loop will affect RHR flow when the isolation valves are opened? _ Describe how this gas volume is vented.
(6)
Proposed TS 3.4.1.6 requires 450 ft* of water in the pressurizer when filling the loop from the RCS volume. How many pressurizer level instruments are required to be operable in these modes? Discuss if these levelinstruments are temperature compensated and any possible effects? What is the instrument uncertainty associated with pressurizer level measurement and was it included in the determination of the 450 ft limit?
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'Mr. J. P. O'Hanlon North Anna Power Station Virginia Electric & Power Company Units 1 and 2 cc:
Mr. J. Jeffrey Lunsford County Administrator Regional Administrator. Region II Louisa County U.S. Nuclear Regulatory Commission P.O. Box 160 Atlanta Federal Center Louisa, Virginia 23093 61 Forsyth St.. SW Suite 23T85 Atlanta. Georgia 30303 Michael W. Maupin, Esquire Hunton and Williams Mr. W. R. Matthews Manager Riv rfront Plaza. East Tower North Anna Power Station 951 E. Byrd Street P. O. Box 402 Richmond, Virginia 23219 Mineral. Virginia 23117 Dr. W. T. Lough Mr. R. C. Haag Virginia State Corporation U.S. Nuclear Regulitory Commission Commission Atlanta Federal Cc.ter Division of Energy Regulation 61 Forsyth St.
SW. Suite 23T85 P. 0. Box 1197 Atlanta, Georgia 30303 Richmond, Virginia 23209 Mr. J. P. O'Hanlon Old Dominion Electric Cooperative Senior Vice President - Nuclear i
4201 Dominion Blvd.
Virginia Electric and Power Company Glen Allen. Virginia 23060 Innsbrook Technical Ceni.er 5000 Dominion Blvd.
Mr. J. H. McCarthy Manager Glen Allen. Virginia 23060 Nuclear Licensing & Operations Support Mr. David Christian. Manager Virginia Electric and Power Company Surry Power Station Innsbrook Technical Center Virginia Electric and Power Company 5000 Dominion Blvd.
5570 Hog Island Road Glen Allen. Virginia 23060 Surry. Virginia 23883 Office of the Attorney General Robert B. Strobe. M.D., M.P.H.
Commonwealth of Virginia State Health Commissioner 900 East Main Street Office of the Commissioner Richmond. Virginia 23219 Virginia Department of Health P.O. Box 2448 Senior Resident Inspector Richmond, Virginia 23218 North Anna Power Station U.S. Nuclear Regulatory Commission 1024 Haley Drive Mineral. Virginia 23117 i
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