ML20081F608

Final Rept Re Significant Const Deficiency 68 Concerning Spurious ESF Actuation Sys Actuation.Initially Reported on 830829.Field Change Modifying Wiring to Connectors Implemented by C-E

ML20081F608
Person / Time
Site:	Waterford
Issue date:	10/20/1983
From:	Gerrets T LOUISIANA POWER & LIGHT CO.
To:	Jay Collins NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV)
References
10CFR-050.55E, 10CFR-50.55E, 2CB-YY, 68, W3K83-1589, NUDOCS 8311030148
Download: ML20081F608 (4)

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LOUISIANA 20WE R & LIG H T/Waterford 3 SES/P. O. Box B/Killona, LA 70066 U[LOl$SY EM October 20, 1983 W3K83-1589 Q-3-A35.07.68

@@]Qg7 Mr. John T. Collins

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Regional Administrator, Region IV i

U. S. Nuclear Regulatory Commission 611 Ryan Plaza Drive, Suite 1000 OCT 2 71983 Arlington, Texas 76012

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REFERENCE:

LP&L letter W3I83-0290 dated August 29, 1983

SUBJECT:

Waterford SES Unit No. 3 Docket No. 50-382 Significant Construction Deficiency No. 68

" Spurious ESFAS Actuation" Final Report In accordance with the requirements of 10CFR50.55(e), we are hereby providing two copics of the Final Report of Significant Construction Deficiency No. 68

" Spurious ESFAS Actuation".

If you have any questions, please advise.

Very truly yours, yw e

T. F. Gerrets Quality Assurance Manager TFG:CKH:VBR cc: Director Office of Inspection & Enforcement U. S. Nuclear Regulatory Commission Washington, D.C.

20555 (15 copies) 8311030148 831020 PDR ADOCK 05000382 S

PDR t\\

JJ-rL

s Mr. John T. Collins October 20, 1983

'W3K83-1589 Page 2 cc: Director Office of Management Information and Program Control U.'S. Nuclear Regulatory Commission Washington, D.C.

20555 Mr. E. L. Blake Shaw, Pittman. Potts, & Trowbridge 1800 M Street, N.W.

Washington, D.C.

20036 Mr. W. M. Stevenson Monroe & Lemann 1424 Whitney Building New Orleans, Louisiana 70130 Record Center Institute of Nuclear Power Operations 1100 circle 75 Parkway, Suite 1500 Atlanta, Georgia 30339 1

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FINAL REPORT OF SIGNIFICANT CONSTRUCTION DEFICIENCY NO. 68

" SPURIOUS ESFAS ACTUATION" INTRODUCTION This report is submitted pursuant to 10CFR50.55(e).

It describes a deficiency that existed in the wiring of the trip peth logic for the Engineered Safety Features Actuation System (ESFAS) actuation. This problem is considered reportable under the requirements of 10CFR50.55(e).

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

DESCRIPTION OF DEFICIENCY On December 17, 1982, a spurious Engineered Safety Features Actuation System (ESFAS) actuation event occurred at SONGS Unit 3 following routine preventive maintenance checks on the Plant Protective System (PPS). As a result, an extensive review of the electrical circuitry was conducted by CE to determine the cause of the actuation. This evaluation revealed that a momentary interruption of the J3109 connection in either Channel A or D used to form the ESFAS matrix logic could result in a complete system actuation as experienced at SONGS Unit 3.

Whether these components were responsible for the event at SONGS Unit 3 still remains a point of conjecture. It has been determined, however, that this condition is applicable to Waterford 3.

SAFETY IMPLICATIONS If left uncorrected, actuation of the Recirculation Actuation Signal (RAS) coincident with a Safety Injection Actuation Signal (SIAS) that has started the HPSI pumps, will cause automatic closure cf the isolation valves in the HPSI pumps miniflow recirculation lines. This situation could result in the HPSI pumps operating against reactor coolant system pressure greater than the shut off head with no recirculation or injection path open, resulting in damage to the pumps. Both trains of engineered safeguards system could, therefore be inoperable simultaneously.

CORRECTIVE ACTION A field change was implemented by CE which modified the wiring going to these connectors. This wiring change exchanged the trip path signals between the J3109 connector in both Channels A and D, such that only half of the matrix and its associated trip path are wired to one connector.

This change will prevent system actuation due to disconnection of the connector and is considered a permanent fix. CE Engineering has reviewed all connectors in the PPS and has found that only the J3109 connector had this design deficiency.

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,o Page 2 In conjunction with the foregoing, a study was initiated to evalucte mechanical system responses to multiple spurious actuation. signals. This study considered multiple ESFAS actuations from normal operating modes. The objective of the study was to verify that any combination of inadvertent actuations (independent of cause) occurring during normal operation, would not i

result in. unacceptable conditions.

It was concluded that, with the exception of the simultaneous SIAS and RAS actuation, all multiple spurious actuations do not result in unacceptable consequences. As described previously, if left uncorrected, the simultaneous action of SIAS and RAS could result in the HPSI pumps pumping against shutoff head and damaging the pumps because the miniflow isolation valves are shut on

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RAS.

A field change has also been implemented to change operation of the four HPSI pump miniflow recirculation valves from automatic to manual operation. These

. valves will, therefore, not close automatically upon actuation of RAS. The guidelines for the operator, stipulating when he must initiate closure of these valves, will be incorporated into the functional based E0P's.

This report is submitted as the Final' Report.

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