B11908, Submits Revised Justification for Continued Operation for Motor-Operated Valve 200 to Reflect Location of Alternative Instrumentation

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Submits Revised Justification for Continued Operation for Motor-Operated Valve 200 to Reflect Location of Alternative Instrumentation
ML20138E225
Person / Time
Site: Haddam Neck File:Connecticut Yankee Atomic Power Co icon.png
Issue date: 11/27/1985
From: Opeka J, Sears C
CONNECTICUT YANKEE ATOMIC POWER CO.
To: Zwolinski J
Office of Nuclear Reactor Regulation
References
B11908, NUDOCS 8512130372
Download: ML20138E225 (3)


Text

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CONNECTICUT YANKEE ATOMIC POWER COMPANY BERLIN. CONNECTICUT P O Box 270 HARTFORD CONNECTICUT 06141-0270 T ELE PHONE 203-665-5000 November 27, 1935 Docket No. 50-213 B11908 Director of Nuclear Reactor Regulation Attn: Mr. John A. Zwolinski, Chief Operating Reactors Branch #5 U.S. Nuclear Regulatory Commission Washington, D.C. 20535

Reference:

(1) 3. F. Opeka letter to J. A. Zwolinski, dated October 25,1935.

Gentlemen:

Haddam Neck Plant Environmental Qualification of Electrical Equipment Justifications for Continued Operation In Reference (1), Connecticut Yankee Atomic Power Company (CYAPCO) submitted supplemented justifications for continued operation (3COs) for the twenty (20) reactor coolant system loop resistance temperature detectors and the fourteen (14) valve motor operators which are not yet fully environmentally qualified. The purpose of this submittal is to revise the JCO provided for MOV 200 to more accurately reflect the location of the alternative instrumentation.

While there is no change to our previous conclusion, a revised JCO is attached.

Should you have any questions regarding this submittal, please do not hesitate to contact us.

Very truly yours, CONNECTICUT YANKEE ATOMIC POWER COMPANY S .%. dea

3. F. Opeka '

Senior Vice President By: C. F. Sears Vice President 8512130372 851127 PDR ADOCK 05000213  %

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Docket No. 50-213 Attachment No. I Haddam Neck Plant Revised Justification for Continued Operation November,1935

- .s SYSTEM: Chemical and Volume Control System (CVCS)

VALVE: 200-Letdown Isolation SAFETY FUNCTION AND JUSTIFICATION FOR CONTINUED OPERATION:

During normal operation, the letdown system takes coolant from the loop I cold leg, cools and depressurizes the water, passes it through filters and demineralizers, then collects the coolant in the volume control tank.

MOV 200 is an isolation valve in the letdown line associated with the chemical and volume control system. This valve is located inside containment, and automatically closes on either a high containment pressure or safety injection signal to minimize the loss of primary system inventory in the event of an accident. Other than isolation purposes, this valve has no accident safety function.

Since this valve is located inside containment, it is subjected to a harsh environment only in the event of a high energy line break inside containment.

There is a high degree of confidence that this valve would be capable of performing its intended function since, in the case of a large break LOCA, the valve would receive a signal to close within 10 seconds and would likely complete its safety function before environmental peaks occur.

Should this valve fail to close, there are three air-operated valves (202,203 and 204) located outside containment which could be closed to isolate the letdown line. Since these valves are located outside containment, they would not be exposed to the same harsh environment that caused the failure of MOV 200.

The only credible failure mode for this valve once it has completed its safety function (i.e., the valve closes) is one where the motor operator continues to operate against the seat of the valve until the circuit trips due to overload or motor failure. This type of failure would not preclude the fulfillment of the safety function of this valve or result in the degradation of any safety function.

With this valve in the closed position, the valve position indication in the control

room could conceivably indicate that the valve is open or not fully closed.

Alternative instrumentation (e.g., letdown flow) whkh is not located in a harsh envicenment is available in the control room to preclude the operator from being misled by inaccurate valve position indication. This instrumentation would not be exposed to the same harsh environment which could cause the f ailure of MOV 200. In addition, EOP 3.1-4 requires the valve breakers to be locked open af ter MOV 200 is closed.

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