ML20084T743

Ro:On 720922,during Routine Calibr,Isolation Condenser High Steam Flow Switches DPIS 3-1350-A & B Found to Actuate at Pressure Above Tech Spec Limits.Cause Not Stated. Procedures Changed to Require Calibr Adjustments

ML20084T743
Person / Time
Site:	Dresden
Issue date:	09/29/1972
From:	Worden W COMMONWEALTH EDISON CO.
To:	Giambusso A US ATOMIC ENERGY COMMISSION (AEC)
Shared Package
ML20084T730	List: ML20084T738 ML20084T743 ML20084T753
References
NUDOCS 8306240085
Download: ML20084T743 (2)

Text

g, D' Commonwealth Edison Company 72 W ES T ADAMS STREET

• C H I C A G O. ILLINOIS Addrene Reply ter POST OFFICC sox 747* C H I C A G O. ILLINOIS 60690 i

Drcsden Nucicar Power Station ch R. R. #1 4 ky Morris, Illinois 60450  %,

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Mr. A. Giambusso Deputy Director for Reator Projects g$- %. <[. /

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U. S. Atomic Energy Comission I Washington, D. C. 20545

SUBJECT:

LICENSE DPR-25. DRESDEN NUCLEAR FC'n'ER STATION UNIT #3, SECTION 6.6.B.2 0F THE TECHNICAL SPECIFICATIONS.

Dear Mr. Giambusso:

This is to report a condition relating to the operation of the station, in which, during routine calibration of the Isolation Condenser high steam flow switches, DPIS-3-1350-A & B and the high condensate flow switches DPIS 3-1349 A & B the setpoints were found to exceed the value specified in Table 3.2.1 of the Technical Specifications.

PROBLEM AND INVESTIGATION On September 22, 1972, during a routine calibration, the Isola-tion Condenser high steam flow switches DPIS 3-1350-A & B were found to actuate at a differential pressure of 426.5" H2O and 435.5" H2O respectively.

The Technical Specification limit as set forth in Table 3.2.1 for the high steam flow switches is 425" H20. The high steam flow switches have a range of 0" to 500" H2O and an accuracy specification of 47. of full scale. The setpoint these switches has previous been set at 417" 13" H20. During cali-bration, with a setpoint of 417" 13" and a fullscale accuracy of 47.,there is sufficient range to prevent the switches from drif ting above the Technical Specification limit.

During the same calibration, the isolation condenser high condensate flow switches DPIS-3-1349 A & B were found with a setpoint of 33.3" H2O and

33.5" H2O respectively. The Technical Specification limic as set forth in l Table 3.2.1 for the high condensate flow switches is 32" H20. The high con-densate flow switches have a range of 0" to 60" H2O and an accuracy specifica-tion of 47. full scale. These switches have previously been set at 30" i 1" H20.

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September 29, 1972 Mr. A. Giambusso With'a setpoint of 30" i 1" H2O and a full scale accuracy of 4% there is sufficient range to prevent the switches from drif ting above the ' Technical Specification limit.

CORRECTIVE ACTION To prevent the high steam flow switch, DPIS 3-1350- A & B, and the high condensate flow switches DPIS 3-1349- A & B, from drif ting above the Technical Specification limits, the station procedures have been changed to require calibration. adjustments to 400" i 5" H2O and 28.5" i 1" H2O respec-tively.

The identical switches on Unit 2 will be adjusted to the same setpoints at the next calibration. These changes should prevent future recurrences of drift beyond Technical Specification in the subject switches.

Sincerely,

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k bb I W. P. Worden Superintendent Dresden Nuclear Power Station 6

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