ML20093K867

Final Rept,Significant Const Deficiency 109 Re Inadequate Design of Qspds/Pps Circuit Interface.Initially Reported on 840524.PMP 302,preparation of Station Mod Packages,Revised to Include Grounding Requirements for All Changes

ML20093K867
Person / Time
Site:	Waterford
Issue date:	07/17/1984
From:	Gerrets T LOUISIANA POWER & LIGHT CO.
To:	Jay Collins NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV)
References
109, W3K84-1640, NUDOCS 8407310219
Download: ML20093K867 (4)

Text

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1 LOUISIANA 342 osanoNoe Smeer P O W E R & L I G H T! R O. BOX 6008

• NEW ORLEANS. LOUISIANA

. (504) 366-2345 70174 sus $SYSE July 17, 1984 W3K84-1640 Q-3-A35.07.109 A i Mr. John T. Collins A)

),

B @ M DMM i Regional Administrator, Region IV  ;

U. S. Nuclear Regulatory Commission a ?.3 m c l 611 Ryan Plaza Drive, Suite 1000 j Arlington, Texas 76012 '

1

REFERENCE:

a) LP&L letter W3K84-1140 dated May 11, 1984 b) Telecon C. Hooper (LP&L) and Eric Johnson (NRC IV) on May 25, 1984 c) Telecon C. Hooper (LP&L) and M. Murphy (NRC IV) on June 6, 1984

SUBJECT:

Waterford SES Unit No. 3 Docket No. 50-382 Significant Construction Deficiency No. 109

" Inadequate Design of QSPDS/PPS Circuit Interface" Final Report In accordance with the requirements of 10CFR50.55(e), we are hereby providing two copies of the Final Report of Significant Construction Deficiency No. 109,

" Inadequate Design of QSPDS/PPS Circuit Iaterface".

If you have any questions, please advise.

Very truly yours,

&~

t/. tt. butit, T. F. Gerrets Corporate Quality Assurance Manager TFG:CNH:VBR Attachment ec: Director Office of Inspection & Enforcement U. S. Nuclear Regulatory Commission Washington, D.C. 20555 (15 copies) 1 8407310219 840717 #

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. Mr. John T. Collins July 17, 1984 W3K84-1640.

- Page 2.

cc: ' Director Office of Management Information and Program Control.

U. S. Nuclesr Regulatory Commission Washington, D.C. 20555 Mr. E. L. Blake

-Shaw, Pittman, Potts & Trowbridge 1800 M Stroet, N.W.

Washington, D.C. 20036-Mr. W. M. Stevenson Monroe & Lemann 1424 Whitney Building New Orleans, Louisiana 70130 Mr. W. A. Cross l 7910 Woodmont Avenue l Suite 1200 Bethesda, Maryland 20814 Records Center Institute of Nuclear Power Operations 1100 Circle 75 Parkway, Suite 1500 Atlanta, Georgia 30339

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. FINAL REPORT OF SIGNIFICAN*.* CONSTRUCTION DEFICIENCY NO. ' 109

" INADEQUATE DESIGN OF QSPDS/PPS CIRCUIT' INTERFACE" l

INTRODUCTION This report is submitted pursuant to 10CFR50.55(e). It describes the electrical grounds on signal common for Channels "C" and "D" of PPS.

To the best of our knowledge, this deficiency has not been reported to the USNRC pursuant to 10CFR21.

DESCRIPTION-  !

In the original design, Channels "C" and "D" of the low pressurizer. pressure signals were connected from the Process Analog Control. cabinets (PAC) CP27 and CP28 to the indicators in CP-7 without isolation. When the QSPDS inputs were

-incorporated into the existing desi n to F meet the_ requirements of NUREG-0737 Item;I.D.2, the signals for the QSPDS were paralleled with the CP-7 indicators, since both signals are in the same safety channels (SMC and SMD).

The existing grounding arrangement in the QSPDS was overlooked.

This connection' introduced an electrical ground on a signal common in Channels ,

"C" an'd "D" of the PPS (which is designed to float) causing Channels "C" and "D" signals to fail high (indicating maximum pressure), thereby preventing initiation of a low pressurizer pressure PPS trip.for Channels "C" and "D".

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Channels "A" and "B" of the same parameter.(Pressurizer Pressure) were unaffected and were operating correctly. The problem with the ground was noticed under the initial test program before the subject instruments were placed in service.

SAFETY IMPLICATIONS [

! If the'above ground problem was left uncorrected, following an actual low pressurizer pressure event, Channels "C" and "D" would fail high and would not initiate a PPS trip.

l CORRECTIVE ACTION TAKEN i

e Station Modification Package (SMP)84-180 and CIWA L-7919 were issued to 1 isolate the QSPDS signal common ground to the PPS by adding Westinghouse NLP-3 i

isolation cards inside PAC panels CP-27 and CP-28. All field work is complete and testing has proven that a PPS trip will be initiated upon receipt of a "Lo" pressurizer pressure signal from Channels "C" and "D".

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-O SCD #109 Page 2 Functional' testing of the PPS has been completed and no additional grounding deficiencies similar to that described above have'been identified. Therefore.

-this is considered an isolated case.

In order to prevent recurrence of deficiencies of this nature, PHP 302, Preparation of Station Modification Packages, has been revised to include grounding requirements for all changes which interface with the Plant Protection System.- In addition the modification program requires that any future design changes be -functionally tested prior to placing in service.

This report is submitted as the Final Report, i

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