ML20077N835

Forwards Addl Info Re Proposed Amend Changing Surveillance Frequency for Valves Associated W/Turbine Overspeed Protection Sys.Encl Ltr from Westinghouse Recommends Monthly Instead of Weekly Testing

ML20077N835
Person / Time
Site:	Mcguire, McGuire
Issue date:	09/07/1983
From:	Tucker H DUKE POWER CO.
To:	Adensam E, Harold Denton Office of Nuclear Reactor Regulation
References
TAC-52111, TAC-52112, NUDOCS 8309130233
Download: ML20077N835 (3)

Text

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DUKE PowEn GoxPm I*.O.HOx 33180 CHAMLOTTE, N.C. 28242 HAL H. TUCKEH TELEPHOME vna emeanestav (704) 3NS31 mm. e-- September 7, 1983 Mr. Harold R. Denton, Director Office of Nuclear Reactor Regulation U. S. Nuclear Regulatory Commiesion Washington, D. G. 20555 Attention: Ms. E. G. Adensam, Chief Licensing Branch No. 4 Re: McGuire Nuclear Station Docket Nos. 50-369, 50-370

Dear Mr. Denton:

Attachment 2 of our letter dated August 1, 1983 contained proposed amendments to Technical Specifications for McGuire Units 1 and 2. The proposed amendments would change the surveillance frequency for the valves associated with the Turbine Over-speed Protection System. This letter provides additional information requested by the NRC staff regarding the proposed amendments.

Attached is a letter by S. E. Bennett of Westinghouse which recommends that the specified turbine valves be tested monthly instead of weekly for BB296 nuclear turbine-generator units utilizing horizontal throttle valve steam chests (TVSC).

This is the type of turbine-generator units installed at McGuire Units 1 and 2.

Also attached is a summary of the preventive maintenance performed on the Turbine Overspeed Protection System. All volatile secondary water treatment is used for McGuire Units 1 and 2.

Please advise if there are additional questions.

Very truly yours,

. gh . j_ ,

tal B. Tucker REH:jfw Attachments (2) cc: Mr. James P. O'Reilly, Regional Administrator Mr. W. T. Orders U. S. Nuclear Regulatory Commission NRC Resident Inspector Region II McGuire Nuclear Station 101 Marietta Street NW, Suite 2900 Atlanta, Georgia 30303 llt F309130233 830907 DR ADOCK 05000

HRD/REH

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,e Attachment 1 ( September 9, 1983 (A2) I W85tingflouSe Power Generation Power Generation Service ,

l Electric Corporation Group 2001 wuoreneaastreet P O Box 32817 May 11, 1983 $Ef7/7poua28232

' Duke Power Company P.O. Box 33189 Charlotte, North Carolina 28242 Attention: Mr. Glen Karasiewicz Subj ect: Westinghouse Recommended Testing Frequency for Steam Admission Valves of Nuclear Turbines with Steam Chests

Dear Sir:

Westinghouse recommends that the throttle, governor, interceptor, and reheat stop valves of nuclear turbine-generator units with steam chests be tested monthly.

Based on a review of testing frequency *and performance data from Westinghouse turbine and component incident records and a 1982 survey of utilities operating Westinghouse nuclear turbines, Westinghouse concluded' that there is no signifi-cant difference in the valve failure rate between valves tested weekly and those tested monthly. It was further noted that monthly versus weekly valve testing frequency may be beneficial because it reduces the time a plant is operating in a " transient state".

This change in policy applies only to BB296 nuclear units utilizing horizontal TVSC's and not the original two on one or one on one inlet valve configurations.

If you have any questions, please contact this office.

I Sincerely, (h

S. E. Bennett Assistant to District Manager Carolinas District SEB:jk l- -

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Attachment 2 HRD/REH September 9, 1983 - (A2)

McGuire Nuclear Station Summary of Preventive Maintenance for the Turbine Overspeed Protection System The McGuire units have a mechanical overspeed protection device in addition to the electronic overspeed protection in the control circuits.

The mechanical overspeed trip is checked by raising the turbine speed to the trip point. This overspeed test is performed once a year.

The overspeed oil trip test is performed once a month. The oil test verifies the freedom of movement of the mechanical overspeed trip assembly and the oil pressure required to move the mechanical trip assembly is proportional to the actual overspeed trip setting.

The turbine valves (throttle, governor, intercept and reheat stops) are all inspected on 40-month cycles. The valves are completely disassembled, clearances checked, non-destructively examined, and, as needed, reassembled with new parts. When the valves are inserted into the valve bodies, the valves are blue-checked with their seats; if required, the valves are lapped for proper seating. Upon completion of assembly the valves are stroked and checked for proper operation.

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