ML20085K067

Final Deficiency Rept Re Control Logic of HPCI & RCIC Sys. Initially Reported on 731110.Four Addl Qualified High Reactor Water Level Switches Will Be Installed

ML20085K067
Person / Time
Site:	Dresden, Browns Ferry, 05000000
Issue date:	01/04/1974
From:	Gilleland J TENNESSEE VALLEY AUTHORITY
To:	US ATOMIC ENERGY COMMISSION (AEC)
Shared Package
ML20085K054	List: ML20085K060 ML20085K063 ML20085K067 ML20085K070
References
10CFR-050.55E, 10CFR-50.55E, NUDOCS 8310200001
Download: ML20085K067 (2)

Text

_ _ _ _ _ _ _ _

s

• a W fp,W%

/%g, 1 TENNESSEE VALL AUTHO AlW E-'"W/7 /

CH ATTANOCGA, TENNESSEE ' . .

I 3740T U$ 7 i .-

-hD l

un

~

, 1974

^)A?d gggy 9 PARTN C A Et HI A

)](

} t (O *2b$

Hr. F. E. Kruesi',' Director 73 Directorate of Regulatory Operations U.S. Atomic Energy Commission Washington, DC 20545

Dear Mr. Kruesi:

In conformance with paragraph 50.55(c) of 10 CFR 50, this is -

submitted as a final report on a design deficiency in the control logic of HPCI and RCIC systems of our Browns Ferry Nuclear Plant units 2 and 3. Initial report of this deficiency was made to AEC-DRO Region II on November 10, 1973, and interim reports were submitted to your office on December 10 and December 14.

Corrective actions to be taken on units 2 and ,3 involve removal of the llPCI and RCIC high reactor water level trips that currently l

originate in the Feedwater Control System, and the installation of I four additional qualified high reactor water level switches. These new switches, with the four existing switches, will be arranged in redundant piping manifolds such that the HPCI and RCIC will cach have four switches (two in each manifold) of which two are powered from the Division 1250-volt d.c. supply and two from the Division II 250-volt d.c. supply. The four switches for each turbine will energize a logic circuit that will trip the machine when either two of the existing switches or two of the new switches are closed by high reactor water level. Units 2 and 3 vill have these modifications made before fuel loading.

Interim corrective actions on unit 1 involved reversing the aspect of the relays in the tripping logic so that they had to be energized to trip, climinating the lockout feature so that manual reset of the t

8310200001 740130 PDR ADOCK 05000249 .

S PDR 1

\ .- .

. . u

- ~ '

.O O Mr. F. E. Kruesi .- January 4, 1974 4

• tripping logic would not be required, and changing the power supply for one channel to a 250-voir d.c. supply through an inverter (see TVA abnormal occurrence report BFAO-7334W, November 11, 1973, E. F.

Thomas to John F. O' Leary) . The corrective actions described above for units 2 and 3 have since been applied to unit 1.

Very truly yours, s

J. E. Gilleland Assistant to the Manager of Power CC: Mr. Norman C. Moseley, Director Directorate of Regulatory Operations U.S. Atomic Energy Commission .

Region II - Suite 818 230 Peachtree Street, NW.

Atlanta, Georgia 30303 l

4 1

4

- p 9

(

O

.