ML20085M907

Clarifies 740104 Final Design Deficiency Rept Re HPCI & RCIC Sys Control Logic,In Response to 740621 Request.Final Mod Reversing Relays in Feedwater Control Trip Logic Installed

ML20085M907
Person / Time
Site:	Browns Ferry
Issue date:	07/10/1974
From:	Gilleland J TENNESSEE VALLEY AUTHORITY
To:	Moseley N NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
Shared Package
ML20085M910	List: ML20085M907 ML20085M913 ML20085M916 ML20085N400
References
NUDOCS 8311090456
Download: ML20085M907 (2)

Text

, -

INOg ./  !

^

TENNESSEE VALLEY As. THORITY i CHATTANOOGA, TENNESSEE y 37401 July 10, 19741 40 ANfWVEASARY OAsETNEYEs"H f

Ifr. Norman C. Moaaley, Director Directorate of Regulatbry Operations U.S. Atomic 4nergy.,Corsaission Rogion IV- Suite'B18 230 Peashtree' St'reet, IM.

Atlatita, Georgia 30303

Dear Mr. Moseley:

A final report on a design deficiency in the control logic of the HPCI and RCIC Systems of the Browns Ferry Nuclear Pinnt unita 2 and 3 was made in our letter to F. E. Krucsi dated January 4, 1974.

On June 21, 1974, Directorate of Regulatory Operations inspector W. S. Little requested clarification of our final report. The following cornsents are provided to clarify our January 4, 1974, reports ,

1. The design deficiency has been corrected for unit 1 as well as for units 2 and 3, and the corrective action for unit 1 was the saue as for unita 2 and 3. .The third paragraph of our January 4,1974, letter describes an interim corrective action for unit 1 which involved reversing the aspect of relays in the feedvater control trip logic. This interim modification was in use from November 11 to December 20, 1973, and no longer applie's '

to any unit. The final modification has been installed on unit 1 as shown on the drawings which you have.

2. When the reactor high water icvel trip signal originated frota.the Feedvater Control System, a manual reset of this signal was required in that system. In the previous circuit configuration, this high reector water level trip had to be reset before the EPCI turbine trip auxiliary relay 23A-K42 could be reset. ' on the 11PCI elementary diagram, Drawing No. 730E928 - sheet 3, relay 23A-K42 was formerly energized when two contacts (in series) from the feedvater control relays 6A-K6A and 6A-K6B were both

-Q,* 0 ,

,,. q 8311090456 740710 PDR ADOCK 05000260 a )M,[ p 38 PDR D J ,

+ _ .

u

,- g ,.

7 5 1

lir. Norman C. Moseley July 10, 19761 closed. These relay contacts were replaced by the two level switches LS-2-3-103B and LS-2-3-103D, as shown on the drawing. The high water level trip for the ITCI and RCIC Systema now occurs, as described in our January 4, 1974, letter, from level switches in the RCIC and IIPCI Systems. There is now no wiring interface between the Feedwater Control System and the safety systems.

3. The four new level switches (two each in IIPCI and PIIC) have arc-suppression networks protecting their contacts in the 250-volt d.c. circuits. Ceneral Electric has successfully tested the level switch contacts, with arc suppression, under an inductive load at 250 volta d.c.'hnd 50 ma. for_more than 100,000 cycles. This test load for the contacts exceeds the demands placed upon the contacts used in the IIPCI System high reactor unter level isolation circuit.

If you have any further questions concerning this deficiency, please do not hesitate to call us.

Very truly yours, J. E. Cilleland '

Assistant to the Ifanager of Power CC: !!r. Donald F. Knuth, Director <

Directorate of Regulatory Operations U.S. Atomic Energy Commission Washington, DC 20545 8

b

[

/

)

.- ~. _ . --

.-/