ML20002B319
| ML20002B319 | |
| Person / Time | |
|---|---|
| Site: | South Texas  |
| Issue date: | 11/17/1980 |
| From: | Tedesco R Office of Nuclear Reactor Regulation |
| To: | Opera G HOUSTON LIGHTING & POWER CO. |
| References | |
| NUDOCS 8012110339 | |
| Download: ML20002B319 (3) | |
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NUCLEAR REGULATORY COMMISSION
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a Mr. G. W. Oprea, Jr.
Executive Vice President Houston Lighting and Power Company P. O. Box 1700 Houston, Texas 77001
Dear Mr. Oprea:
SUBJECT:
INSERVICE INSPECTION OF PRESSURE ISOLATION VALVES l
(South Texas Project, Unit Nos.1 and 2)
/ s a result of our review of your application regarding inservice inspection af pressure isolation valves, we require the following information:
Provide a list of pressure isolation valves incluhd in your testing program with four (4) sets of piping and inctrumen-tation diagrams which clearly show the reactor coolan'. syster l
isolation valves. Also, discuss in detail how your leak test-l ing program conforms to the staff position (see enclosure).
l l
It is requested that this infomation be provided within 15 days of receipt of this letter. This position has previously been provided to your staff.
Sincerely,
/
l Robert L. Tedesco, Assistant Director for Licensing Division of Licensing i
Enclosure:
l Staff Position -
Inservice Inspection of Pressure Isolation '/alves, September 22, 1980 yn19119b
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Mr. G. W. Oprea, Jr.
Executive Vice President Houston Lighting and Power Company P. O. Box 1700 Houston, Texas 77001 cc: Mr. D. G. Barker Richard N. Lowerre, Esq.
Manager, South Texas Project Assistant Attorney General Houston Lighting and Power Company Environmental Protection Division P. O. Sox 1700 P. O. Box 12548 Houston, Texas 77001 Capitol Station Austin, Texas 78711 Mr. M. L. Borchelt Central Power and Light Company Shannon H. Phillies P. O. Box 2121 Resident Inspector / South Texas Project Corpus Christi, Texas 78403 c/o V. S. NRC P. O. Box 910 Mr. R. L. Hancock Bay City, Texas 77414 City of Austin Electric Utility Department Mr. R. Jacobi P. O. Box 109S Houston Lighting and Power Company Austin, Texas 78767 P. O. Box 1700 Houston, Texas 77001 Mr. J. B. Poston Assistant General Manager for Operations Pat Coy City Public Service Board Citizens Concerned About Nuclear Poser P. O. Box 1771 5106 Casa Oro San Antonio, Texas 78296 San Antonio, Texa's 78233 Jack R. Newman, Esq.
Lowenstein, Newman, Axelrad & Toll 1025 Connecticut Avenue, N.W.
Washington, D.C.
20036 Melbert Schwarz, Jr., Esq.
Baker & Botts One Shell Plaza Houston, Texas 77002 Mr. J. R. Geurts Brown & Root, Inc.
P. O. Box 3 Houston, Texas 77001 Mrs. Peggy Buchorn Executive Director Citizens for Equitable Utilities, Inc.
Route 1, Box 1684
^
Brazonia, Texas 77422 D
210.0 MECHANICAL ENGINEERING BRANCH There are several safety systems connected to the reactor coolant pressure boundary that have design pressure below the rated reactor coolant system (RCS) pressure. There are also some systems which are rated at full reactor pressure on the dischargt side of pumps but have pump suction below RCS pressure.
In order to protect these systems from RCS pressure, two or more 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 prevent exceeding the design pressure of the low pressure systems thus causing an inter-system LOCA.
Pressure isolation valves are required to be category A or AC per IWV-2000 and to meet the appropriate requirements of IWV-3420 of Section XI of the ASME Code except as discussed below.
Limiting Conditions for Operation (LCO) are required to be added to the technical specifications which will require corrective action i.e., shutdown or system isolation when the final approved leakage limits are not met. Also surveillance requirements, which will state the acceptable leak rate testing frequency, shall be provided in the technical specifications.
Periodic leak testing of each pressure isolation valve is required to be performed at least once per each refueling outage, after valve maintenance prior to return to service, and for systems rated at less than 50% of RCS design pressure each time the valve has moved from its fully closed position unless justification is given. The testing interval should average to be approximately one year. Leak testing should als7 be performed after all disturbances to the valves are complete, prior to reaching power operation following a refueling outage, maintenance and etc.
l The staff's present position on leak rate limiting conditions for operation must be equal to or less than 1 gallon per minute for each valve (GPM) to ensure the integrity of the valve, demonstrate the adequacy of the redundant pressure isolation function and give an indication of valve degradation over a finite l
period of time. Significant increases over this limiting valve would be an indication of valve degradation from one test to another.
t Leak rates higher than 1 GPM will be considered if the leak rate changes are below 1 GPM above the previous test leak rate or system design precludes measuring 1 GPM with sufficient accuracy. These items will be reviewed on a case by case basis.
The Class 1 to Class 2 boundary will be considered the isolation point which must be protected by redundant isolation valves.
In cases where pressure isolation is provided by two valves, both will be inde-pendently leak tested. When three or more valvas provide isolation, only two of the valves need to be leak tested.
l Provide a list of all pressure isolation valves included in your testing program
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along with four sei.s of Piping and Instrument Diagrams which describe your reactor coolant system pressure isolation valves. Also discuss in detail how your leak -
testing program will conform to the above staff position.
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