ML20067C567
| ML20067C567 | |
| Person / Time | |
|---|---|
| Site: | Quad Cities  |
| Issue date: | 02/04/1991 |
| From: | Stols R COMMONWEALTH EDISON CO. |
| To: | Murley T NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM), Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 9102120114 | |
| Download: ML20067C567 (2) | |
Text
I Commonwealth Edison 1400 Opus Place U
Downers Grove, Illinois 60515 February 4, 1991 Dr. Thomas E. Hurley, Olrector Office of Nuclear Reactor Regulatton U.S. Nuclear Regulatory Commission Washington, D.C.
20555 Attn:
Document Control Desk
Subject:
Quad Cities Nuclear Power Station Unit i fast Acting Solenoid Valve (FASV)
Pressure Switch Setpoint MBC_Do.cLeLNom50:2M i
Reference:
(a) R. Stols to T.E. Hurley letter dated December 18, 1990.
(b) H.H. Richter to T.E. Murley letter dated January 23, 1990.
Dr. Hurley:
The reference (a) letter transmitted an appilcation to facility Operating License DPR-29, Appendix A Technical Specification.
The proposed amendment reflects a modification to the fast ecting solenoid valves _which initiate rapid closure of the turbine control valves.
The new design for the fast acting solenoid valve utilizes a pressure switch (In lieu of a ilmit switch) to initiate a reactor scram.
As a result, the pressure switches require periodic calibration and have a setpoint for actuation of the reactor scram.
Following the submittel, Dresden Station performed calibration of the pressure switches wnich demonstrated substantial drift of the pressure switch setpoint.
(for additional information, see reference (b).) The calibration was performed after approximately twenty-four (24) month period.
In response to these findings, Quad Citles Station personnel contacted five-(5) non-Edison plants to inquire if substantial drift was experienced with the pressure switches for the fast closure of the turbine contro; valves.
Each plant responded that they had not experienced excessive drift and four (4) plants provided some data to support their finding.
The data provided is as follows:
Number of Instruments InitrumentDrlf_tJ ange (ps1 )
- _lo_Dr_LfLBange 9
0-25 8
26-50 1
/
jff 1j()Ay 51-75 2
76-100 4
f((g 101-130 1
>l30 0
yen.r e f m 9102120114 910204 PDR ADOCK 05000254 P
Dr. T.E. Hurley February 4, 1991 Also it should be noted that although a setpoint drift of 1104 psig (for an 18 month period) was used in the General Electric calculation, the final determination of 590 psig as the nominal setpoint allows for a drift of r130 psig.
Finally, the analytical limit of 400 psig (which ensures that the trip signal will be generated within 30 milliseconds after the start of control valve fast closure) provides additional margin.
Please direct any questions concerning t'.is submittal to R. Stols at 708/515-7283.
Very truly yours, R. Stols Nuclear Licensing Administrator cc:
A.B. Davis, Region III Administrator L.N. 01shan, Project Manager, NRR T. Taylor, Senior Resident Inspector l^
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