ML20083D712

Proposed Tech Specs Requiring Turbine Overspeed Protection Sys to Be Demonstrated Operable at Least Once Per 31 Days

ML20083D712
Person / Time
Site:	North Anna
Issue date:	12/21/1983
From:	VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.)
To:
Shared Package
ML20083D700	List: ML20083D699 ML20083D712
References
NUDOCS 8312280223
Download: ML20083D712 (7)

Text

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e ATTACaiENT 1 8312280223 831221 e

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05000338 PDR

PLANT SYSTEMS TURBINE OVERSPEED LIMITING CONDITION FOR OPERATION 3.7.1.7 At least one turbine overspeed protection system shall be OPERABLE.

APPLICABILITY: MODE 1, 2 and 3 ACTION: With the above required turbine overspeed protection system inoperable, within 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> either restore the system to OPERABLE status or isolate the turbine from the steam supply.

SURVEILLANCE REE.,IREMENT 4.7.1.7.1 The provisions of Specification 4.0.4 are not applicable.

4.7.1.7.2 The above required turbine overspeed protection system shall be demonstrated OPERABLE.

At least once per 31 days by cycling each of the following valves l

a.

through one complete cycle.

1.

4 Turbine Throttle valves 2.

4 Turbine Governor valves 3.

4 Turbine Reheat Stop valves 4.

4 Turbine Reheat Intercept valves b.

At least once per 31 days by direct observation of the movement of each of the above valves through one complete cycle.

At least once per 18 months, by performance of CHANNEL CALIBRATION c.

on the turbine overspeed protection instruments, d.

At least once per 40 months, by disassimbly of at least one of each of the above valves and performing a visual and surface inspection of all valve seats, disks and stems and verifying no unacceptable flaws or corrosion.

NORTH ANNA - UNIT 1 3/4 7-15

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PLANT SYSTEMS TURBINE OVERSPEED LIMITING CONDITION FOR OPERATION OPERABLE.

At least one turbine overspeed system shall be 3.7.1.7 MODE 1, 2 and 3 APPLICABILITY:

tion system With the above required turbine overspeed protecin t m to OPERABLE ACTION:

supply.

status or isolate the turbine from the steam SURVEILLANCE REQUIREMENT licable.

The provisions of Specification 4.0.4 are not app shall be 4.7.1.7.1 4.7.1.7.2 The above required turbine overspeed protection system demonstrated UPERABLE:

following valves l

least once per 31 days by cycling each of the Atthrough one complete cycle.

a.

4 Turbine Throttle valves 1.

4 Turbine Governor valves 2.

4 Turbine Reheat Stop valves 3.

4 Turbine Reheat Intercept valves f the movement of 4.

i At least once per 31 days by direct observat on o l te cycle.

each of the above valves through one comp e b.

f CHANNEL CALIBRATION At least once per 18 months, by performance o nts.

on the turbine overspeed protection instrume c.

f at least one of each At least once per 40 months, by disassembly ol and surface inspection of the above valves and performing a visuad verifying no unacceptable d.

of all valve seats, disks and stems an flaws or corrosion.

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3/4 7-12 NORTH ANNA - UNIT 2 l

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DISCUSSION OF PROPOSED TECHNICAL SPECIFICATION CHANGE Presently, North Anna 1 and 2 Technical Specification 4.7.1.7.2a requires that at least once per 7 days the four turbine throttle valves, four turbine governor valves, four turbine reheat stop valves and four turbine reheat intercept valves are cycled through one complete cycle.

The proposed North Anna 1 and 2 Technical Specification change would allow the turbine valves to be cycled through one complete cycle at least once per 31 days.

The turbine valves have never failed to close during a reactor trip, turbine trip or during the weekly cycling of the valvea.

Unit I has been testing these valves weekly for four years and Unit 2 for over three years.

Power reductions required to perform these tests reduce unit capacity factors and require replacement generation.

The cycling of these valves produces mechanical and thermal shocks to the steam, condensate and drain systems.

Performance of this test produces secondary instability, challenges the secondary control systems and increases the risk of turbine and reactor trip.

When ramp rate limitations are in effect requiring a slow power reduction and slow return to full power, a generation loss of approximately 250 MWe-hrs. is necessary to perform this test on one unit.

The tu:bine valves have proven exceptionally reliable over the previous years of testing.

A monthly test is more than adequate to demonstrate valve freedom.

Any statistical advantage provided by a weekly test is clearly outweighed by the lost generation and potential risk to station equipment.

In addition, the Westinghouse generic recommendation for testing the turbine valves is to test on a monthly interval.

This proposed change does not involve a significant increase in the probability or consequences of an accident, it does not create the possibility of a new or different kind of accident previously evaluated and it does not involve a significant reduction in the margin of safety because the turbine valves have proven to be very reliable in the past.

There has never been a failure of the turbine valves during a reactor trip, turbine trip or during weekly cycling.

The Westinghouse generic recommendation for testing the turbine valves is to test on a monthly interval.

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VIR0l!Ik ELECTRIC AND POWER COMPANY 01 CHECK V UCHER BANK NO CHECK NO DATE VENDOR No LINE DATE INVOICE NO /CP DESCRIPTION GROSS AMOUNT DISCOUNT NET AMOUNT 7Td/3b/83 NA 152 TECH SPEG CHANGE 4,400.00 0.00 4,400.00 ATTACHED CHECK ISSUED AS PAYMENT OF ITEMS LISTED ABOVE - PLEASE DETACH STUB AND CASH CHECK PROMPTLY.68-589 VIRGINIA ELECTRIC AND POWER COMPANY RICHMOND. VIRGINIA BANK OF VIRGINIA WHITE STONE. VA VOID IF NOT CASHED IN 90 DAYS 03301 25 1356220 00000440000 FOUR THOUSAND FOUR HUNDRED AND 00/100 DOLLARS BK CHECK NO.

DATE VENDOR NO AMOUNT T

to UNITED STATES NUCLEAR oEo'R REGULATORY COMMISSION 25 1356220 12/21/83 3301

$4,400.00 l

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