ML20137B376
| ML20137B376 | |
| Person / Time | |
|---|---|
| Issue date: | 03/20/1997 |
| From: | Weidenhamer G NRC OFFICE OF NUCLEAR REGULATORY RESEARCH (RES) |
| To: | Kalsi M KALSI ENGINEERING, INC. |
| Shared Package | |
| ML20137B379 | List: |
| References | |
| NUDOCS 9703210305 | |
| Download: ML20137B376 (2) | |
Text
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[o j NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 2055M001 4'
.....l March 20, 1997 Dr. M. S. Kalsi Kalsi Engineering, INC.
745 Park Two Drive Sugar Land, Texas 77478-2885
Dear Dr. Kalsi:
This letter responds to your request of February 28, 1997, regarding the acquisition of Idaho National Engineering Laboratory (INEL) pressure locking test data for the 6" Walworth flexible wedge gate valve. Your letter requests closing thrust magnitudes for specific static and pressure locking tests identified in the table attached to the letter. You also stated that the data is needed for the purpose of validating the enhanced Comed pressure locking methodology being supported by the BWR Owner's Group.
After receiving your letter, the test data at INEL was reviewed to determine the availability of the data you requested. The results cf the review showed that the maximum closing thrust was measured for the static tests that you identify in your letter; however, the maximum closing thrust was not measured during any of the pressure locking tests. The maximum closing thrust was not measured during the tests because the objective of the test program was to determine the magnitude of the valve openina thrusts when subjected to various internal pressures and temperatures simulating pressure locking scenarios.
The maximum closing thrust was measured for the static tests to determine the magnitudes of the unwedging forces and the friction forces resulting from stem packing.
Since the maximum closing thrusts were not measured during the pressure locking tests, I called Dr. Wang, of your staff, to inform him of the results of the review. I also informed him that although the maximum closing thrusts were not available from the pressure locking tests, the values of the relaxed closing thrusts could be provided for the same tests. After explaining what the relaxed thrust means, Dr. Wang stated that the relaxed thrust data would be acceptable for his needs.
The Table in the attachment to this letter contains the data that you /
requested and that Dr. Wang agreed to. The test numbers, in the left column, correspond to the tests that were identified in your request. The " Type of
//
/
I Test" information, in the second column, is self explanatory. The " Maximum /
Stem Thrust During Wedging" contains the closing thrust data you requested.
The last column i', labelled " Relaxed Stem Thrust Just Prior to Unwedging" and '{-ff5 contains the closing thrust values discussed with Dr. Wang.
To explain the relaxed stem thrust data requires an understanding of the stem thrust of a typical gate valve during a closure stroke. At torque switch trip, events occur that cause the current to the actuator motor to be switched off; however, the valve thrust continues to increase due to the inertia 9703210305 970320 PDR Qld,[d%E{E%l%hl,%
Dr. M. S. Kalsi 2 ,
effects of the motor and actuator components. At the instant the motions of the motor and actuator components stop, the thrust reaches a maximum then it begins to decrease. The decrease in thrust is due to relaxation of the elastic deformations in the valve and actuator components that were caused by the applied motor torque, the inertia, and the forces acting on valve internals during closure. The relaxation of the thrust will generally i stabilize in typical MOVs after a short period of time. The thrust values internals during closure. The relaxation of the thrust will generally stabilize in typical M0Vs after a short period of time. The thrust values given in the relaxed stem thrust column, and agreed to by Dr. Wang, are the closing thrusts after the relaxations have stabilized.
The relaxed thrusts were measured because the instrumentation was energized prior to beginning the opening stroke for each of the pressure locking tests. l The thrust in the stem prior to opening the disk for a pressure locking test is the relaxed stem thrust resulting from disk closure after the previous pressure locking test was completed.
The closure thrusts provided in the attachment were obtained from work l sponsored by an agency of the United States Government. Neither the United States Government nor any agency thereof, nor any of their employees, makes any warranty, expressed or implied, or assumes any legal liability or responsibility of any third party's use, or the results of such use, of any information disclosed in the attachment, or represents that its use by such third party would not infringe privately owned rights.
If you have any questions regarding the data or the processes for performing the static and pressure locking tests, please call me on (301) 415-6015. I i
Sincerely Gerald H. Weidenhamer Electrical, Materials & Mechanical Engineering Branch Office of Nuclear Regulatory Research
Attachment:
As stated ,
4 Distribution: (with Kalsi Letter)
Signature File (LCS)
Branch Reading File R.H.Wessman G.E. Grant T.G.Scarbrough S.G.Tingen E.J. Brown Document Control Desk Public Document Room DOCUMENT NAME: G:\WEIDENHA\KALSI ,
Ta ,eceive e copy of this document,Jpditate f in the boa: "C" = Copy without attachment / enclosure *E' = Copy with attachment / enclosure *N* = No copy 0FFICE DET/EMMEBMAJ E DET/EMMES'ffcJl DET/EMME W l l NAME GWeidenhamer:lc JVora W MMayfield "f T -
DATE 3 ' dom 15/ yc/91 3/a/7 7
' 0FFICIAL RECURD COPY
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