ML080920522

Summary of Facility Changes, Tests and Experiments During 2007 Pursuant to 10 CFR 50.59(d)(2)

ML080920522
Person / Time
Site:	North Anna
Issue date:	03/24/2008
From:	Stoddard D Virginia Electric & Power Co (VEPCO)
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
08-0125
Download: ML080920522 (3)

Text

VIRGINIA ELECTRIC AND POWER COMPANY RICHM0OND, VIRGINIA 23261 March 24, 2008 United States Nuclear Regulatory Commission Serial No. 08-0125 Attention: Document Control Desk NAPS/JHL Washington, D. C. 20555 Docket Nos. 50-338 50-339 License Nos. NPF-4 NPF-7 Gentlemen:

VIRGINIA ELECTRIC AND POWER COMPANY (DOMINION)

NORTH ANNA POWER STATION UNITS 1 AND 2

SUMMARY

OF FACILITY CHANGES, TESTS AND EXPERIMENTS Pursuant to 10 CFR 50.59(d)(2), enclosed is a summary description of Facility Changes, Tests and Experiments identified in Regulatory Evaluations implemented at the North Anna Power Station during 2007.

If you have any questions, please contact Page Kemp at (540) 894-2295.

Very truly yours, D. G. Stoddard Site Vice President Attachment cc: U. S. Nuclear Regulatory Commission Region II Atlanta Federal Center 61 Forsyth St., SW, Suite 23T85 Atlanta, Georgia 30303 NRC Senior Resident Inspector North Anna Power Station JtL(7 KtMA

ATTACHMENT 10 CFR 50.59

SUMMARY

DESCRIPTION OF FACILITY CHANGES. TESTS AND EXPERIMENTS North Anna Power Station Units 1 and 2 Virginia Electric and Power Company (Dominion)

ý- ' ý NORTH ANNA UNITS 1 & 2 10 CFR 50.59

SUMMARY

DESCRIPTION OF FACILITY CHANGES, TESTS AND EXPERIMENTS REGULATORY EVALUATION: 07-SE-OT-01 Document Evaluated: Engineering Transmittal-NAF-07-0047, Rev. 0, Changes to the North Anna Containment Analyses and LOCA Alternate Source Term Analyses for Reduced RS Pump Flow Rates Brief

Description:

The plant safety analysis was revised to reduce the minimum assumed flow rates for the inside and outside recirculation spray (RS) pumps.

Reason for Change: Implement changes to the North Anna Units 1 and 2 UFSAR Chapter 6 containment analysis and LOCA Alternate Source Term analysis in UFSAR Chapter 15 to incorporate a reduction in the minimum recirculation spray (RS) pump flow rates, Summary: The IRS pump flow rate is changed from 3100 gpm to 3050 gpm. The ORS pump flow rate is changed from 3450 gpm to 3350 gpm. This change was made to provide margin for the RS pump test program. For NRC GSI-1 91, the design basis debris head loss that is applied to the RS strainers increases the suction head loss and reduces the minimum delivered flow.

The GOTHIC containment analyses in calculations SM-1 511-1, SM-1 512-00B, and SM-1513-1 demonstrate that the containment design criteria continue to be met for revised flow rates of 3050 gpm for the IRS pumps (50 gpm reduction) and 3350 gpm for the ORS pumps (100 gpm reduction). The LOCA containment depressurization analyses continue to be bounded by the limits from the LOCA dose consequences analysis basis from Technical Specification Change Request N-051. Containment pressure is less than or equal to 42.7 psig (Pa) in the first hour after a LOCA, is less than 2.0 psig during the period 1-6 hours after the LOCA, is sub-atmospheric within 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />, and remains sub-atmospheric thereafter. Further, the containment pressure and temperature profiles remain within the equipment qualification limits. The reduced flow rates were also analyzed for the effect on NPSH available for the RS and low head safety injection (LHSI) pumps. There was a 0.1 ft reduction in RS pump NPSH margin and a 0.3 ft reduction in the LHSI pump NPSH margin during recirculation. The LHSI and RS pumps continue to have sufficient NPSH margin to meet the new design basis head loss requirements.