ML17252B020

Letter Reporting a 09/22/1972 Discovery of DPIS-3-1360-A and B and the High Condensate Flow Switches DPIS 3-1349 a and B Setpoints to Be Above the Technical Specifications - Dresden Unit 3

ML17252B020
Person / Time
Site:	Dresden
Issue date:	09/29/1972
From:	Worden W Commonwealth Edison Co
To:	Giambusso A US Atomic Energy Commission (AEC)
References
Download: ML17252B020 (2)

Text

Commonwealth Edison Company 72 WEST ADAMS *sTREET

• CHICAGO, ILLINOIS Addrur Reply fo, POST OFFICE BOX 767 *CHICAGO, ILLINOIS 60690 Dresden Nuclear Power R. R. #1 Morris, Illinois 60450 September 29, 1972 50-249 Mr. A. Giambusso Depu~y Director for Reator Projects Directorate of Licensing U. S. Atomic Energy Commission Washington, D. C. 20545

SUBJECT:

LICENSE DPR-25. DRESDEN NUCLEAR POWER STATION UNIT #3, SECTION 6.6.B.2 OF THE TECHNICAL SPECIFICATIONS.

Dear Mr. Giambusso:

Thi:s is to report a condition relating .to the operation of the station, in which, during routine. c~libration of the Isolation Condenser

• high steam flow switches, DPIS-3~°1360-A & B and the high. condensate flow

~ * '* ...... ,_; ....;>~: I' \ '

switches DPIS 3-1349 A & Bthe 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" H20 and 435.5" H20 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 O" to 500" H2*p and an accuracy specification of 4% of full scale. The setpoint these switches has previous been set at 417" + 3" H20. During cali-bration, with a setpoint of 417" +/- 3" and a fullscale accuracy of 4%,there is sufficient range to* prevent the switches from drifting 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" H20 and 33.5" H20 respectively. The Technical Specification limit as set forth in Table 3.2.1 for the high condensate flow switches is 32 11 H20. The high con-densate flow switches have a range of O" to 60" H20 and an accuracy specifica-tion of 4% full scale. These switches have previously been set at 30" +/- 1 11 H20.

... ~ :;\ "'1 Mr. A. Giambusso

• September 29, 1972 With a setpoint of 30" +/- l" H20 and a full scale accuracy- of 4% there is ;-,:1 sufficient range to prevent the switches from drifting 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 drifting above the Technical Specification limits, the station procedures have been changed to require calibration adjustments to 400" +/- 5" H20 and 28. 5" +/- l" H20 respec-tively.

• ' The identical swiiches on: *Unit 2 will be adjusted to the same setpoints -at. the next ,calibration *. These changes should prevent future rec~rr_en_ces of_:dr~ft beyorid Techilical._ l)peciffCation in the subject switches.

• " . Sincerely,

• ,1 ~ i .- *,.,,

W. P. *worden Superintendent Dresden Nuclear Power Station WPW:do