ML17301A150

Special Rept:On 841220,during Surveillance Run of Diesel Generator 2B While Unit Shut Down,Radiator Cooling Fan Hub Found Loosened & Cracked Circumferentially.Mod Issued to Eliminate Possibility of Set Screw Loosening

ML17301A150
Person / Time
Site:	Saint Lucie
Issue date:	01/21/1985
From:	Williams J FLORIDA POWER & LIGHT CO.
To:	James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
References
L-85-39, NUDOCS 8502210303
Download: ML17301A150 (2)

Text

FLORIDA POWER & LIGHT COMPANY 85JAN29 pP ~

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January 21, 1985 L-85-39 Mr. James P. O'Reilly Regional Administrator, Region II U. S. Nuclear Regulatory Commission Suite 2900 101 Marietta Street, NW Atlanta, GA 30323

Dear Mr. O'Reilly:

Re: St. Lucie Unit 2 Docket No. 50-389 Special Report - Diesel Generator The information in this special report is submitted in accordance with Technical Specification 4.8. 1.'1.3 for St. Lucie Unit 2.

j On December 20, 1984, during a surveillance run of the 2B Diesel Generator (D/G) while the plant was shutdown, the operator noted a problem at one of the radiator cooling fans and. stopped the D/G. The investigation showed that set screws securing the fan hub and its key to the shaft had loosened, the hub was loose, and the hub had a circumferential crack. Since a new fan hub had to be fabricated, a plant change/modification was issued to enhance its design to eliminate the possibility of the set screws coming loose. The PCM was incorporated on the 2B D/G 12 cylinder engine fans only. All other fans were checked and found satisfactory for continued use, however, the new hubs are to be installed on the remaining Unit 2 D.G fans as a reliability enhancement.

This is the second problem with the 28 Diesel Generator in the last 100 valid tests. The 2B D/G was out of service for 96 hours0.00111 days <br />0.0267 hours <br />1.587302e-4 weeks <br />3.6528e-5 months <br /> as a result of this event. The plant remained shutdown during the period the D/G was out of service. The current surveillance interval for the St. Lucie Unit 2 Diesel Generators is not more than 7 days in accordance with Regulatory Position C.2.d. of Reg. Guide 1.108.

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Nr. James P. O'Reilly January 21, 1985 Page 2 Should you or your staff have any questions on this information, please contact us.

Very truly yours, J. W. Williams, Jr.

Group Vice President Nuclear Energy JWW/PLP/js Attachment cc: Harold F. Rei s, Esquire P NS-L I-85-040-1