ML20155D178
| ML20155D178 | |
| Person / Time | |
|---|---|
| Site: | South Texas  |
| Issue date: | 10/29/1998 |
| From: | Jordan T HOUSTON LIGHTING & POWER CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| NOE-AE-000319, NOE-AE-319, NUDOCS 9811030139 | |
| Download: ML20155D178 (3) | |
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.m October 29,1998 NOC-AE-000319 File No.: G021.02.01, G03.16.
-10CFR50 STI: 30725261 U.S. Nuclear Regulatory Commission Attention: Document ControlDesk Washington, DC 20555-0001 South Texas Project Units 1 and 2 Docket Nos. STN 50-498, STN 50-499 Response to Staff Questions on Proposed Amendment to Technical Specifications 3.7.1.6, Atmosoheric Steam Relief Valves
Reference:
Letter from T. H. Cloninger, South Texas Project, to the Nuclear Regulatory Commission dated August 18,1997 (ST-~HL-AE-5689)
In response to staff questions on the referenced letter regarding the Amendment to Technical P
Specifications 3.7.1.6 on Atmospheric Steam Relief Valves, the STP Nuclear Operating Company hereby submits the requested information. Attached are the questions with answers as posed by the NRC staff.
This letier contains no new commitments to the NRC. Should you have any questions in regard to this response, please contact Mr. T. M. Stroschein at (512) 972-7734 or me at (512) 972-7902.
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.. Jordan,
- Manager, Systems Engineering l
Attachment 9811030139 981029 yDR ADOCK 05000498 PDR
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File No.: G21.02.01 G03.16 Page 2 Ellis W. Merschoff-Jon C. Wood Regional Administrator, Region IV Matthews & Branscomb U. S. Nuclear Regulatory Commission' One Alamo Center
' 611.Ryan Plaza Drive, Suite 400 106 S. St. Mary's Street, Suite 700 Arlington, TX ~ 76011-8064 San Antonio, TX 78205-3692 Thomas W. Alexion...
Institutd of Nuclear Power Project Manager, Mail Code 13H3 Operations - Records Center
- U. S. Nuclear Regulatory Commission 700 Galleria Parkway Washington, DC 20555-0001 '
Atlanta, GA 30339-5957 Cornelius F. O'Keefe Richard A. Ratliff Sr. Resident Inspector Bureau of Radiation Control c/o U. S. Nuclear Regulatory Commission Texas Department of Health
' P. O. Box 910 1100 West 49th Street Bay City, TX 77404-0910-Austin, TX 78756-3189
)
J. R. Newman, Esquire
. D. G. Tees /R. L. Balcom-Morgan, Lewis & Bocklus Houston Lighting & Power Co.
1800 M. Street, N.W.
P. O. Box 1700 Washington, DC 20036-5869
- Houston,TX 77251 M. T. Hardt/W. C. Gunst Central Power and Light Company City Public Service:
- ATTN: G. E. Vaughn/C. A. Johnson P. O. Box 1771 P. O. Box 289, Mail Code: N5012 I San Antonio, TX 78296 Wadsworth,TX 77483-A. Ramirez/C. M. Canady U. S. Nuclear Regulatory Commission City of Austin Attention: Document Control Desk Electric Utility Department Washington, D.C. 20555-0001' 721 Barton Springs Road '
Austin,TX 78704 s
ATTACHMENT Question)
Explain how the atmospheric steam relief valves operate to ensure sufficient cycling capability.
Answer)
The atmospheric steam relief valves are hydraulically actuated. Each valve has a small, completely self-contained hydraulic plant located immediately above the valve. The hyd aulic plant consists of a positive displacement pump, an accumulator, a reservoir (for hydraulic fluid), a manifold, a servo-valve, a servo-amplifier, solenoid valves, check valves, flow control valves, relief valves, pressure switches, a level switch, tubing and various fittings and electrical connections. This plant is connected directly to the valve's hydraulic operating cylinder.
The hydraulic pump operates as necessary to charge hydraulic fluid into the accumulator from the reservoir. By doing so, the pump forces hydraulic fluid into the accumulator and compresses the nitrogen charge that is present on the opposite side of the internal moveable piston. This stored energy in the compressed nitrogen in the accumulator provides the motive force to move the i
accumulator piston, thus forcing hydraulic fluid out of the accumulator and into the operating cylinder of the valve, causing the valve to stroke. The amount of nitrogen within the accumulator and the amount of hydraulic fluid that circulates in the hydraulic plant are finite and these fluids do not interface with any other plant system or any other valve. The components of the hydraulic plant are arranged so that the valve may be stroked in the open or closed direction from the control room.
The hydraulic pump is powered by 480 VAC class 1E power. The control circuitry is powered by 125 VDC class lE power. The valve may be operated on a continuous basis provided that the power supplies and the valve and valve actuator components do not fail. If power is lost, the valve is capable of stroking by using stored energy in the accumulator.
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