ML20064K100

Final Rept of Const Deficiency 6 Re Defective Shafts & Springs for Cooper-Bessemer Emergency Diesel Generators. Caused by Addl Length on Splined End of Shafts & Cracks in Spring Base Metal.New Shaft Fabricated & Spring Reworked

ML20064K100
Person / Time
Site:	Waterford
Issue date:	09/18/1980
From:	Crnich J, Hartnett R, Milhiser R LOUISIANA POWER & LIGHT CO.
To:
Shared Package
ML20064K097	List: ML20064K096 ML20064K100 ML20064K104 ML20064K106
References
10CFR-050.55E, 10CFR-50.55E, NUDOCS 8009290396
Download: ML20064K100 (3)

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LOUISIANA POWER & LIGHT COMPANY WATERFORD SES UNIT No. 3 i

Final Report of Significant Construction Deficiency No. 6 el Emerge cy Diesel Generators-Defective Shafts & Springs t

Reviewed by -

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J CrnicE - Site Manager Date '

Reviewed by  ! M ~

i R. J. Millfiser - Project Superintendent Date #

Reviewed by

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N, 59 l J. Hart - Project Licensing Enginesir /Date I Reviewed by m R. A.Jdartnett - Q. A. Site Supervisor l $

f Date '

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September 18, 1980 1

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FINAL REPORT SIGNIFICANT CONSTRUCTION DEFICIENCY NO. 6 EMERGENCY DIESEL GENERATORS-DEFECTIVE SHAFTS & SPRINGS

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I INTRODUCTION This report is submitted pursuan.c to 10CFR50.55(e) (3). It describes a i deficiency in'the emergency diesel generators supplied by Cooper-Bessemer Company for LP&L's Water. ford Steam Electric Station Unit No. 3.

DESCRIPTION On July 25, 1978, Cooper-Bessemer company pursuant to 10CFR21 notified the USNRC - Of fice of Inspection and Enforcement, Washington, D. C. , of e defective shafts and springs in the Emergency Diesel Generators supplied for LP&L's Waterford SES Unit No. 3 at-Taft, Louisiana.

A. Shafts i

The defect exists in the two shaf ts which drive th2 engine speed control gcvernor and the engine overspeed shutdown governor on each engine. The splined driven end of the shaf ts was manuf actured two inches longer than

required by design specification. The additional length causes the shaft I spline to misalign with the splined drive bushing, resulting in marginal engagement of the splined surf aces. This defect is considered to be reportableland is described in Attachment A (Cooper-Bessemer Co. letter to NRC dated July 25, 1978).

B. Springs The defect exists in a spring which operates the overspeed shutdown butter-

q fly valve on the engine turbochanger air inlet connection. The spring is plated with electrolytically deposited cadmium to prevent corrosion. Several l

identical springs have recently 2, ailed on units still in the process of manu-i facture at C.E.S. The cause of failure has been determined to be cracks in the base metal caused by the electrolytic plating process. This defect is i considered to be non-reportable and is described in Attachment B (Cooper i

Energy Services letter to NRC dated July 25, 1978).

i l j SAFETY IMPLICATIONS A. Shafts If the units were to fail during operations, the following consequences would result:

Overspeed Shutdown Governor shaft failure, only - The unit would continue to operate normally, but would lose overspeed protection.

Speed Control Governor shaf t f ailure, only - The unit speed would rapidly proceed to overspeed, at which point the Overspeed Governor would effect a shutdown of the unit.

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Simultaneous failure of both shaf ts - The unit speed would rapidly increase out of control until a mechanical f ailure occurred, placing the unit out of service.

B. Springs If the units were operational and the spring were to f ail, one of the two overspeed protection devices provided on each engine would f ail to perform.

However, the other overspeed protection device, a fuel shut-off mechanism activated by a mechanically driven speed governor, would not be af fected by the spring failure and would provide independently effective engine overspeed protection.

I-CORRECTIVE ACTION 8

Cooper Energy Services has fabricated new governor drive shaf ts , thus correct-ing the deficiency in the length of the shaft.

The defective spcing has been remanuf actured f rom a material that will not crack as a result of the electrolytic plating process.

Replacement of the new shafts and springs was accomplished by Gulf Engineering Company, Inc., under the supervision of a Cooper-Bessemer representative. The work was completed during the week ending September 19, 1980, and is docu-mented in Gulf Engineering Traveler Nos. PS-233 and P5-229.

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