ML20062M425

Final Rept of Significant Const Deficiency 47 Re Defect in AKR-30/50 Circuit Breaker.Ge Circuit Breaker Failed to Recharge Closing Spring.Field Insp Revealed Backed Out & Broken Flat Screw Heads.Replacement Screw Ordered

ML20062M425
Person / Time
Site:	Waterford
Issue date:	08/11/1982
From:	Mclendon G LOUISIANA POWER & LIGHT CO.
To:	Jay Collins NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV)
References
10CFR-050.55E, 10CFR-50.55E, W3K-82-0509, W3K-82-509, NUDOCS 8208200096
Download: ML20062M425 (5)

Text

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f 142 DELAROP,DE STREET

. P O W E R & L I G H T! P O BOX 6008 NEW+ORLEANS LOUISlANA 70174 e (SO4) 366 2345

=arswa August 11, 1982 G. D. McLENDON Senior Vice Presodent W3K 82-0509 Q-3-A35.07.47 Mr. John T. Collins, Regional Administrator, Region IV U. S. Nuclear Regulatory Commission 611 Ryan Plaza Drive, Suite 1000 Arlington, Texas 76012

SUBJECT:

WJterford SES Unit No. 3 Do:ket No. 50-382 l'inal Report of Significant Construction Deficiency No. 47

" General Electric AKR-30/50 Circuit Breakers Closing Spring Screw"

Reference:

Telecon - L. L. Bass (LP&L) to W. Crossman (NRC) on July 2,1982

Dear Mr. Collins:

In accordance with the requirements of 10CFR50.55(e), we are hereby providing two copies of the Final Report of Significant Construction Deficiency No. 47, " General Electric AKR-30/50 Circuit Breakers Closing Spring Screw."

If you have any questions, please advise.

Very truly yours, GDMcL/LLB/grf AttacInnent o'7 ,s

]l cc: 1) Director jb($bODb Office of Inspection & Enforcement U. S. Nuclear Regulatory Commission Weshington, D. C. 20555 (with 15 copies of report) gg i 3 1982

2) Director Office of Management Infonnation and Program Control U. S. Nuclear Regulatory Commission Washington, D. C. 20555 (with 1 copy of report) 96 820011 hf,k8jjjjK05000362 S

PDR '

LOUISIANA POWER & LIGIIT COMPAW WATERFORD SES UNIT NO. 3 Final Report of Significant Construction Deficiency No. 47 General Electric AKR-30/50 circuit Breakerc Closing Spring crew S Reviewed by // g -

R. J.'Mf1hiser - Site Manager 2*

Date Reviewed by J.[ Wills - Project Superintendent ,

Date Reviewed by_ g f, 1

[ llart - Projec/ Licensing 5ngineer"~ B 'v ~B z" Date Reviewed by_ J W. Yacger-4 Sr. Resident Engineer b h1

1. Date Reviewed by _ g hk

[ Cutierrez - Q. A. S pi Supervisor ['[~[Z-Date l

- . - ._ _- = . .- _ . _ _ _ _ _ _ - . _ _

FINAL REPORT SIGNIFICANT CONSTRUCTION DEFICIENCY NO. 47 GENERAL ELECTRIC AKR-30/50 CIRCUIT BREAKERS CLOSING SPRING SCREW INTF0 DUCTION This report is submitted pursuant to 10CFR50.55(e). It describes a defect with the AKR-30/50 circuit breaker. The problem was a possible failure of the circuit breaker to recharge the closing spring. This problem is considered reportable under the requirements of 10CFR50.55(e). To the best of our know-ledge, this problem has not been identified to the USNRC pursuant to 10CFE21. .

DESCRIPTION General E1cetric Service Advice 175-9.7 advised of potential problems with -

the AKR-30/50 circuit breaker which resulted from an intermittent omission of thread locking compound on a flat head screw on the lower end of the closing  ;

spring assembly. This omission could have resulted in the screw interfering with the charging of the circuit breaker's closing spring, thus keeping the breaker from closing.

SAFETY IMPLICATIONS During field inspections, it was confirmed that the flat head screws on the ,

closing spring circuit breaker assembly were found " backed out" in three in- r stances. We therefore concluded that the failure of subject breakers could have adversely affected the equipment important to safety if it was left uncorrected. This would have been in conflict with the intent of Criterion 17 of 10CFR50 Appendix A and therefore was reportable. l CORRECTIVE ACTION A field inspection was performed on all AKR-30/50 breakers (78) on site and documented on NCR W3-3180. Of this number, three (3) flat head screws were found to be " backed out" and one (1) flat head screw was found broken off. This one flat  ;

head screw found broken of f has been documented on Nonconformance Report W3-3541.

Locktite was applied, and the three screws were reinstalled and torqued.to 60 inch-pounds. A replacement screw was ordered from General Electric and installed ,

with the use of locktite applied and tested after a 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> waiting period. NCR W3-3541 and W3-3180 have been closed. All documentation subject to SCD 47 has been reviewed and verified by Quality Assurance.

We are submitting this report as our Final Report to the USNRC.

O

• O LOUISIANA POWER & LIGilT COMPAIN WATERFORD SES UNIT NO. 3 Final Report of Significant Construction Deficiency No. 47 General Electric AKR-30/50 circuit Breakers Closing Spring Screw Reviewed by ./I d [2

• R. J.'Mflhiser - Site Manager Date Reviewed by J./ Wills - Project Superintendent '

Date Reviewed by // [/J8 [ <e d 8 -d ~[&

Date

[. Hart - Projec,d Licensing Engineer"'

Reviewed by b h1 W. Yaeger 4 Sr. Resident Engineer I Date ,

/

Reviewed by .M ['["[L Date Gutierrdz - Q. A. Sip Supervisor

FINAL REPORT SIGNIFICANT CONSTRUCTION DEFICIENCY NO. 47 GENERAL ELECTRIC AKR-30/50 CIRCUIT BREAKERS CLOSING SPRING SCREW INTRODUCTION This report is submitted pursuant to 10CFR50.55(c). It describes a defect with the AKR-30/50 circuit breaker. The problem was a possible failure of the circuit breaker to recharge the closing spring. This problem is considered reportable under the requirements of 10CFR50.55(e). To the best of our know-ledge, this problem has not been identified to the USNRC pursuant to 10CFR21.

DESCRIPTION General Electric Service Advice 175-9.7 advised of potential problems with the AKR-30/50 circuit breaker which resulted from an intermittent omission of thread locking compound on a flat head screw on the lower end of the closing spring assembly. This omission could have resulted in the screw interfering with the charging of the circuit breaker's closing spring, thus keeping the breaker from closing. ,

SAFETY IMPLICATIO3 During field inspections, it was confirmed that the flat head screws on the closing spring circuit breaker assembly were found " backed out" in three in-stances. We therefore concluded that the failure of subject breakers could have adversely affected the equipment important to safety if it was left uncorrected. This would have been in conflict with the intent of Criterion 17 of 10CFR50 Appendix A and therefore was'reportabic.

CORRECTIVE ACTION A field inspection was performed on all AKR-30/50 breakers (78) on site and documented on NCR W3-3180. Of this number, three (3) flat head screws were found to be " backed out" and one (1) flat head screw was found broken off. This one flat head screw found broken off has been docomented on Nonconformance Report W3-3541.

Locktite was applied, and the three screws were reinstalled and torqued to 60 '

inch-pounds. A replacement screw was ordered from General Electric and installed with the use of locktite applied and tested af ter a 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> waiting period. NCR W3-3541 and W3-3180 have been closed. All documentation subject to SCD 47 has been reviewed and verified by Quality Assurance.

We are submitting this report as our Final Report to the USNRC.

. - __