ML20086F627

AO 50-261/75-10:on 750521,boric Acid Transfer Pump B Failed.Caused by Shaft Being Broken at Keyway & Worn Pump Bearing.Pump Rebuilt

ML20086F627
Person / Time
Site:	Robinson
Issue date:	06/02/1975
From:	Utley E CAROLINA POWER & LIGHT CO.
To:	Moseley N NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
Shared Package
ML20086F628	List: ML20086F627 ML20086F630
References
AO-50-261-75-10, NG-75-826, NUDOCS 8401030445
Download: ML20086F627 (3)

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• Carohna Power & Light Company June 2, 1975 bt FILE: NG-3513 (R) SERIAL: NG-75-826 Mr. Norman C. Moseley, Director U. S. Nuclear Regulatory Cocu:lission

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Region II, Suite 818 ,

230 Peachtree Street, N. W. ,n

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Atlanta, Georgia 30303 jQ ~~

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Dear Mr. Moseley:

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11. B. ROBINSON UNIT NO. 2 'h sd LICENSE NO. DPR-23 #

FAILURE OF "B" BORIC ACID TRANSFER PUMP In accordance with 6.6.2.a of the Technical Specifications for

11. B. Robinson Unit No. 2, the attached Abnormal Occurrence Report is submitted for your information. This report fulfills the requirement for a written report within ten days of an Abnormal Occurrence and is in accordance Revision 1. with the format set forth in Regulatory GuideJine 1.16, Yours very truly, W j  ?

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E. . Utley Vice President Bulk Power Supply DBW:cpw Attachment

- CC: Mr. N. B. Bessac Mr. P. W. Ilowe Mr. R. L. Jones Mr. D. Knuth

!Ir. J. B. McGirt Mr. D. B. Waters 8401030445 750602 PDR ADOCK 05000261 S PDR 336 Fayettevi'e Street . P O Gox 1551. Raleigh. N C. 27602 G289

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ABNORMAL OCCURRENCE REPORT j 4

1. Peport No. 50-261/75-10 2a. Date May 28, 1975 2b. Occurrence Date May 21, 1975

3. Facility H. B. Robinson Unit No. 2 Hartsville, South Carolina 29550

4. Identification of Occurrence Failure of "B" Boric Acid Transfer Pump constituting an abnormal occurrence as defined in Section 1.8.d of the Technical Specifications.

5. Conditions Prior to Occurrence The plant was in a cold shutdown to perform maintenance work. "B" Boric Acid Transfer Pump was lined up to recirculate "B" Boric Acid Tank. "A" Boric Acid Transfer Pump was lined up to recirculate "A" Boric Acid Tank and the pump was in operation at this time.

6. Description of Occurrence At 0217 hours0.00251 days <br />0.0603 hours <br />3.587963e-4 weeks <br />8.25685e-5 months <br /> the "B" Boric Acid Transfer pump was lined up to recirculate "B" Boric Acid Tank and put into service. At 0345 hours0.00399 days <br />0.0958 hours <br />5.704365e-4 weeks <br />1.312725e-4 months <br /> the'pung was found stopped with the breaker in tripped position. The breaker was reset, but tripped again when an attempt was made to start the pump. "A" Boric Acid Transfer Pump was operable and running at this time. Steps were taken at this time to determine the cause of "B" pump failure.

7. Designation of Apparent Cause of Occurrence The pump motor was checked electrically and found to b'e sound. Investi-gation revealed the shaft had broken at the keyway. The pump bearing showed some wear and this appeared to have created some vibration and ultimate failure.

8. Analysis of Occurrence At the time "B" Boric Acid Transfer Punp failed, the "A" Boric Acid Transfer Pump was also in operation. The plant safety was, therefore, not jeopardized, and no limiting condition of operation was violated.

No personnel injuries, undue exposures, releases of radioactive materials, or threat to the public health and safety resulted from this occurrence.

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9. Corrective Action The "B" Boric Acid Transfer Pump was rebuilt with spare 4ts f rom stock' and returned to service at 0858, May 22, 1975. A new pump model GVH-10K has been reconnended by Chempump and has been ordered. In the meantime, the GE 20K stub shaft modification is in progress and will also bd -installed in an effort to alleviate the shaft breakage problems. ~

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10. Failure Data l August 15, 1973 Crane Chempump model GE 20K broken shaft near keyway.

December 4, 1973 Crane Chempump model CE 20K broken shaf t near keyway.

March 20, 1974 Crane Chenpump model GE 20K broken shaf t near Leyway.

August 8, 1974 Crane Chempump model GE 20K broken shaf t near keyway.

l August 26, 1974 Crane Chempump model GE 20K broken shaf t at rotor (pump end) .

December 4, 1974 Crane Chempump model GE 20K broken shaf t at rotor (pump end).

May 21, 1975 Crane Chempump model GE 20K broken shaf t near keyway.

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