ML20085M913

Final Deficiency Rept Re Defect in HPCI & RCIC High Reactor Water Level Trips.Initially Reported on 731110.Aspect of Relays in Tripping Logic Will Be Reversed

ML20085M913
Person / Time
Site:	Browns Ferry
Issue date:	01/04/1974
From:	Gilleland J TENNESSEE VALLEY AUTHORITY
To:	Kruesi F US ATOMIC ENERGY COMMISSION (AEC)
Shared Package
ML20085M910	List: ML20085M907 ML20085M913 ML20085M916 ML20085N400
References
10CFR-050.55E, 10CFR-50.55E, NUDOCS 8311090457
Download: ML20085M913 (2)

Text

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g ENNESSEE VALLEY ALTTHORITY

CHATTANOOGA, TENNESSEE 37401

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Jnnuary 4, l'Ph 40 ANNIVE ASA AY OF PEOPLE IN PA ATNE ASHIP 4

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3 i Mr. F. E. Kruesi, Director

Directorate of Regulatory Operations s U.S. Atomic Energy Commission " -

I Washington, DC 20545 11

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Dear Mr. Kruesi:

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g In conformance with paragraph 50.55(e) of 10 CFR 50, this is

. submitted as a final report on a design deficiency in the control ..~ f1 p logic of HPCI and RCIC systems of our Browns Ferry Nuclear Plant 7 units 2 and 3. Initial report of this deficiency was made to AEC-DRO Region 11 on November 10, 1973, and interim reports were  ;.

submitted to your office on December 10 and December 14.

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Correc t ive ac tions to be taken on units 2 and 3 involve removal

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E of the HPCI and RCIC high reactor water level trips that currently 1 . .,...s. <

[ originate in the Feedwater Control System, and the installation of M .

g four additional qualified high reactor water level switches. These IYy_ -l..,A i new switches, with the four existing switches, will be arranged in g redundant piping manifolds such that the HPCI and RCIC will each  %

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[ have four switches (two in each manifold) of which two are powered ,,ii,%

@ from the Division 1 250-volt d.c. supply and two from the Divisioe 11 - #'$9.:

f 2 50-vo l t d.c. supply. The four switches for each turbine will  ;

L energir.e a logic circuit that will trip the machine when either two ) ;Y k -7,' #

of the existing switches or two of the new switches are closed by high reactor water level. Units 2 and 3 will have these modifications gi

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• Q.g.,yf r made before fuel loading. g}

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_ Interim corrective actions on unit 1 involved reversing the aspect .7 7.J. c'pC ~

[ of the relays in the tripping logic so that they had to be energized {Th,';j7{i {

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to trip, eliminating the lockout feature so that manual reset of the ,. # %, y y& ,, - ,

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' 8311090457 740710 ,

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, Mr. F. E. Krucsi January 4, 1974 l

tripping logic would not be required, and changing the power supply for one channel to a 250-volt d.c. supply through an inverter (see TVA abnormal occurrence report BFAO-7334W, November 19, 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, 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 J

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