ML20079M329

Provides Status Rept of Progress on Resolving GDC 17 Analysis Re Rerating of Motor Operated Valves & Plan for Further Work as Committed to in .Verified Valve Torque Requirements Obtained for All Valves

ML20079M329
Person / Time
Site:	North Anna
Issue date:	01/20/1984
From:	Stewart W VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.)
To:	Harold Denton, John Miller Office of Nuclear Reactor Regulation
References
038, 38, NUDOCS 8401270268
Download: ML20079M329 (3)

Text

O VINGINIA 13LECTHIC AND PowEn CoMI'ANY llICIIM OND, VI NG INI A 2112 61 W.L.SrawAar Vics PumminsNr Nect. set rysBANONS January 20, 1984 Mr. Harold R. Denton, Director Serial No.

038 Office of Nuclear Reactor Regulation PSE/BSD:cdk:009N Attn:

Mr. James R. Miller, Chief Docket Nos.

50-338 Operating Reactors Branch No. 3 50-339 Division of Licensing U. S. Nuclear Regulatory Commission License Nos. NPF-4 Washington, D.C.

2055 NPF-7 Gentlemen:

GENERAL DESIGN CRITERIA 17 ANALYSIS NORTH ANNA UNIT NOS. 1 AND 2 The purpose of this letter is to provide a status report of our progress on resolving the rerating of motor operated valves (MOVs) and our plan for further work as committed to in our October 14, 1983 letter, Serial No. 557.

We have obtained verified valve torque requirements for all valves.

A complete review of the alignment of valves in the plant and the control circuitry for each MOV has determined that 74 of the original 130 MOVs will not need to operate in an emergency when the voltage on the 480 volt bus is below 90 percent of the MOV rated voltage. The remaining 56 MOVs will be rerated.

Attached is our updated plan to resolve this item.

Since the additional valve information needed to complete the torque calculations was obtained during the Fall 1983 maintenance outages, we anticipate completion of MOV rerate by the end of third refueling after September 1, 1982, as requested in letter 557.

Very truly yours,

-n bb W. L. Stewar l

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VsaanutA Ex.acrase AND POWEB COMPANY TO i

Mr. Harold R. Denton Page 2 cc:. Mr.-R. C. DeYoung, Director NRC Office of-Inspection and Enforcement Division of Reactor Operations Inspections Washington, D.C.

20555-Mr. J. P. O'Reilly Regional Administrator - Region II' i Mr. M. W.-Branch NRC Resident Inspector - North Anna Power Station t

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NORTH ANNA POWER STATION UNIT 1 AND 2 MOV RERATE AND REPLACEMENT PRELIMINARY PLAN 1.

Verify which valves must operate on an SI or CDA.

(completed) 2.

Verify required torques to operate valves based on calculations for all except butterfly or wafer valves.

(completed) 3.

Provide comparisons of required torques for butterfly and wafer valves.

(completed) 4.

Limitorque has previously provided information on the torque capabilities of the motor operators and will be requested to determine if a torque switch limiter plate replacement or reset i

is required. We presently anticipate that this will be completed by April 1984.

5.

Design Change Packages (DCP) will then be developed to make these modifications. We anticipate that the DCP 82-29A for Unit I and DCP 82-29B for Unit 2 will be available by October 1984.

6.

Implementation will occur as feasible in the next refueling and intervening maintenance outages O

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1 STATUS OF VEPC0 MOV ANAL'(SIS HORTH ANNA POWER STATION UNIT NOS. 1 AND 2 1.

Total number of MOVs on original list 130 2.

Number of MOVs which are not required to operate on SI or CDA 74 3.

Number of MOVs which are required to operate on SI or CDA 56 4.

Number of MOVs in #3 which can be rerated (may require torque switch limiter plate replacement) 56 5.

Number of MOVs in #3 which require replacement or modification of the motor operators 0

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