ML19339A022

Forwards Staff Position Re Inservice Insp of Pressure Isolation Values.Requests List of Pressure Isolation Valves Included in Testing Program & Details on Leak Testing Program by 801107

ML19339A022
Person / Time
Site:	Summer
Issue date:	10/27/1980
From:	Tedesco R Office of Nuclear Reactor Regulation
To:	Nichols T SOUTH CAROLINA ELECTRIC & GAS CO.
References
NUDOCS 8010310555
Download: ML19339A022 (5)

Text

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7FDP OCTOBER 2.7 E Docket No. 50-395 Mr. T. C. Nichols, Jr.

Vice President and Group Executive Nuclear Operations South Carolina Electric and Gas Company Post Office Box 764 Columbia, South Carolina 29218

SUBJECT:

INSERVICE INSPECTION OF PRESSURE ISOLATION VALVES As a result of our review of your application for the Virgil C. Sun:ner Nuclear Station, Unit I regarding inservice inspection of pressure isolation valves, we require the following infonnation:

Provide a list of pressure isolation valves included in your testing program with four (4) sets of piping and instrumentation diagrams which clearly show the reactor coolant system isolation valves. Also, discuss in detail how your leak testing program confonns to the enclosed staff position.

It is requested that this infonnation be provided by November 7,1980. This position has previously been provided to your staff.

Sincerely, orinnal si::ned by Robert L. Tedesco Robert L. Tedesco, Assistant Director for Licensing Division of Licensing

Enclosure:

Staff Position Inservice Inspection of Pressure Isolation Valves, September 22, 1980 SEE ATTACHED SHEET _FOR DISTRIBUM ON

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. C. Nichols, Jr.

Vice President & Group Executive p

Nuclear Operations South Carolina Electric & Gas Company P. O. Box 764 i

Columbia, South Carolina 29281

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cc: Mr. William A. Williams, Jr.

Vice President South Carolina Public Service Authority 223 North Live Oak Drive l

Moncks Corner, South Carolina 29461 t

t J. B. Knotts, Jr., Esq.

Debevoise_& Liberman_ ______

1200 17th Street, N. W.

Washington. D. C.. 20036.__

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Mr. Mark B. Whitaker, Jr.

Group Manager - Nuclear Engineering & Licensing South Carolina Electric T. Gas Company

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P. O. Box 764 Columbia, South Carolina 29218

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7 Mr. Brett Allen Bursey

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Route 1, Box 93C Little Mountain, South Carolina 29076 1

l Resident Inspector / Summer NPS c/o U. S. NRC Route 1, Box 64 3

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ENCLOSURE 9/22/80

_ Staff Po-* tion

_ Inservice Inspection of Pressure Isolation Valves There are several safety systems connected to the reactor coolant pressure iary that have d2 sign pressure below the rated reacter coolant system oressure. There are also some systems which are rated at full reactor te on the discharge side of pumps but have pump suction below RCS ptsssure.

In order to protect these systems from RCS pressure, two or more

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isolation valves are placed in series to form the interface between the high pressure RCS and the low pressure systems. The leak tight integrity of these valves must be ensured by periodic leak testing.to prever.t exceeding the design pressure of the low pressure systems thus c'ausing an inter-system LOCA.

Pressure isolation valves are required to be Category A or AC per -IWV-2000

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and to meet the appropriate requirements of IWV-3420 of Section XI of the ASME.ade except as discussed below.

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Limiting Conditions for Operation (LCO) are required to be added to the

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A technical specifications.which will require corrective action i.e., shutdown Y

or system isolation when the final approved leakage limits are not met.

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'. ' Also surveillance requirements, which will state the acceptable leak rate g-testing frequency, shall be provided in the technical specifications.

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g Periodic leak testing of each pressure isolation valve is required to be pertormed at least once.per each refueling outage, after valve maintenance y.

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prior to return:.t.o ' service and each the the valve has moved from its

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should average to be approximately one year. Leak testing should also be performed'after all disturbances to the valves are complete, prior to reaching k-power operation following a refueling outage maintenance and etc.

4 The staff's present position on leak rate limiting conditions for operation must be equal to or less than 1 gallon per minute to ensure the integrity of the valve, demonstrate the adequacy of the redundant pressure isolation function

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Significant increases over this limiting value would be an indication of valve degradation from one test to another, c

Y-Leak rates higher than i GPM will be considered if the leak rate changes are

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below 1 GPM above the previous test leak rate or system design precludes i,

, measuring,1 GPM wi.th sufficient accuracy. These items will be reviewed on a

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The Class 1 to Class 2 boundary will be considered the isolation point whi,ch 7

must be protected by redundant isolation valves.

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In cases.where-pressure isolation if provided by two yalves, both will be Y'pr

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