ML18153A305
| ML18153A305 | |
| Person / Time | |
|---|---|
| Site: | Surry  |
| Issue date: | 04/22/1998 |
| From: | Ohanlon J VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.) |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| RTR-NUREG-0737, RTR-NUREG-737, TASK-2.F.1, TASK-TM 98-173, NUDOCS 9804290015 | |
| Download: ML18153A305 (2) | |
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VIRGINIA ELECTRIC AND POWER COMPANY RICHMOND, VIRGINIA 23261 April 22, 1998 United States Nuclear Regulatory Commission Attention: Document Control Desk Washington, D.C. 20005 Gentlemen:
VIRGINIA ELECTRIC AND POWER COMPANY SURRY POWER STATION UNITS 1 AND 2 Serial No.
NL&OS/GDM Docket Nos.
License Nos.98-173 RO 50-280 50-281 DPR-32 DPR-37 REVISED COMMITMENT TO NUREG-0737, SECTION 11.F.I, ATTACHMENT 5 CONTAINMENT SUMP LEVEL MEASUREMENT NUREG-0737, "Clarification of TMI Action Plan Requirements," provided various requirements to be implemented by licensees in response to the lessons-learned from the March 1979 accident at Three Mile Island Unit 2.
One such post-accident monitoring requirement was specified in Item 11.F.I, Attachment 5, Containment Water Level Monitor. This item required licensees of pressurized water reactors (PWR) to provide the following monitoring capability:
"A continuous indication of containment water level shall be provided in the control room for all plants.
A narrow range instrument shall be provided for PWRs and cover the range from the bottom to the top of the containment sump. A wide range instrument shall also be provided for PWRs and shall cover the range from the bottom of the containment to the elevation equivalent to a 600,000 gallon capacity.... "
Item 11.F.I, Attachment 5 also included five clarifications associated with the containment water level monitoring requirement, including Clarification (2), that stated "The measurement capability of 600,000 gallons is based on recent plant designs. For older plants with smaller water capacities, licensees may propose deviations from this requirement based on the available water supply capability at their plant."
Virginia Electric and Power Company provided its response for implementing containment water level monitoring in a letter to the NRG dated December 15, 1980 (Serial No. 985), and in a subsequent letter dated February 18, 1983 (Serial No. 076).
In these letters, we stated that we were installing wide range level transmitters with a range of up to nine (9) feet above the containment floor which is equivalent to about 600,000 gallons.
This equivalency was based on a calculation that correlated containment elevation with contained water volume. A recent review of this calculation 9804290015 980422 PDR ADOCK 05000280 p
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determined that the final data point that correlated water volume at nine feet above the contai.nmenr sump floor was in error. The original calculation had determined that the containment water volume at the nine feet level was 600,688 gallons, however, the corrected volume is actually 579,993 gallons. This reduced value is not a design or operability concern for the level monitor since a conservative estimate of the water level in containment with all available water sources appropriately emptied is only about 458,600 gallons. This maximum volume of water correlates to approximately 7.5 feet above the containment sump floor which is well within the wide range transmitter measurement range of O to 9 feet.
Consequently, this letter is provided to clarify the commitment made in our earlier letters which stated that 9 feet above the containment floor is equivalent to about 600,000 gallons. The actual measurable volume is 579,993 gallons which is still well above the actual water volume that is available for discharge to the containment.
If you have any questions or require additional information, please contact us'.
Very truly yours, Commitment Summary:
The wide range level transmitters used to monitor the containment sump* water level following an accident can measure a range from zero to nine feet above the containment sump floor. The nine feet elevation is equivalent to approximately 580,000 gallons.
cc:
U. S. Nuclear Regulatory Commission Region II Atlanta Federal Center 61 Forsyth Street, SW, Suite 23T85 Atlanta, Georgia 30303 Mr. R. A. Musser NRC Senior Resident Inspector Surry Power Station