ML18095A841
| ML18095A841 | |
| Person / Time | |
|---|---|
| Site: | Salem  |
| Issue date: | 04/02/1991 |
| From: | Labruna S Public Service Enterprise Group |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| LCR-91-01, LCR-91-1, NLR-N91054, NUDOCS 9104080138 | |
| Download: ML18095A841 (3) | |
Text
Public Service Electric and Gas Company Stanley LaBruna Public Service Electric and Gas Company P.O. Box 236, Hancocks Bridge, NJ 08038 609-339-1200 Vice President - Nuclear Operations APR o 2 199t NLR-N91054 LCR 91-01 United States Nuclear Regulatory Commission Document Control Desk Washington, DC 20555 Gentlemen:
SUPPLEMENTAL INFORMATION MSIV CLOSURE TIME EXTENSION REQUEST FOR LICENSE AMENDMENT SALEM GENERATING STATION UNIT NO. 1 FACILITY OPERATING LICENSE NO. DPR-70 DOCKET NO. 50-272 This letter provides information in support of PSE&G's application for an amendment to Appendix A to Facility Operating License DPR-70, Salem Generatin*g Station Unit No. 1.
The amendment request, transmitted via letters dated February 1, 1991 (NLR-N91001) and March 19, 1991 (NLR-N91041), proposes to allow use of the eight second Main Steam Isolation Valve (MSIV) closure time during Salem Unit l's tenth cycle of operation.
During a March 13, 1991 telephone conversation, Mr. J. Huang (Mechanical Engineering Branch -
NRR) requested information regarding the hydraulic actuator for the Salem MSIV's.
Specifically, Mr. Huahg asked how PSE&G determined the effect of the actuators' check valves on MSIV closure.
Atwood & Merril, the MSIV vendor representative, performed hydraulic actuator refurbishment and testing.
After being reconditioned (including cleaning, lapping of the poppet to t~e seat and spring replacement), each check valve was installed in a test fixture (see attached figure).
Hydraulic fluid was poured into the top of the fixture until the volume above the poppet was full.
A manual hydraulic pump was used to slowly pressurize the fluid above the poppet until an oil drop passed the seat.
The pressure was gradually reduced a few tenths of one psi until fluid leakage stopped.
The pressure measured at this point (cracking pressure) was 93 psid.
Subsequently, the check valves were remounted to the hydraulic actuator.
A pressure gage was installed in order to measure pressure between the check valves and the top of the hydraulic piston.
While cycling the actuator with its hydraulic pump, full f\\oo\\
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Document Control Desk NLR-N91054 APR o 2 1991 check valve lift was determined to occur at 103 psid, which remained steady during the entire stroke of the hydraulic piston in the MSIV closure direction.
The 10 psi difference between check valve cracking pressure and full opening is the result of the dynamic effect of flow past the poppet, due to poppet and seat geometry, in combination with spring resistance.
For the purposes of determining the effect of the check valves on the initiation of MSIV closure, a nominal value of 100 psi cracking pressure was used.
Using the ratio of the area of the hydraulic piston to the steam actuator piston, the presence of the check valves was determined to require an additional 46 psid steam pressure to initiate MSIV closure.
As described in PSE&G's letter of February 1, 1991, the 46 psid value was used to correlate MSIV closure test data from the D.C. Cook plant with the calculated pressure required to close the Salem MSIV's.
Should you have any questions or comments on this transmittal, do not hesitate to contact us.
Attachment C
Mr. J. c. Stone Licensing Project Manager Mr. T. Johnson Senior Resident Inspector Sincerely, Mr. T. Martin, Administrator Region I Mr. Kent Tosch, Chief New Jersey Department of Environmental Protection Division of Environmental Quality Bureau of Nuclear Engineering CN 415 Trenton, NJ 08625
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