ML20087B792

SR-S1-75-07:on 751025,during Movement of Manipulator Crane, Manipulator Outer Cast Inadvertently Driven Into Upper Internals Package & Damaged Drive Shaft at Core Location P-8.Drive Line Tested & Acceptable for Reuse

ML20087B792
Person / Time
Site:	Surry
Issue date:	11/28/1975
From:	Stallings C VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.)
To:	Moseley N NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
References
SR-S1-75-07, SR-S1-75-7, NUDOCS 8403090367
Download: ML20087B792 (4)

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VIIHilNIA I$i.I Critic AND l'OWI:It COFsI%N Y _

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!!r. Norman C. Moseley, Director Serial No. 791 Office of Inspection and Enforcement POLM/JTB:clw U.S. Nuclear llegulatory Commission Region II - Suite 818 . Docket No. 50-280 230 Peachtree Street, Northwest Licence No. DPR-32 Atlanta, Georgia 30303 ,

Dear Mr. Moseley:

The Virninia Electric and Power Company hereby submits forty (40) copier of Special Report No. SR-S1-75-07 describing a recent event which occurred at the Surry Power Station, Unit No. 1.

The substance of this report han been reviewed by both the Station iniclear' Safety and Operating Committee and the System Nuclear Saf ety and Operating Committee.

I Very truly youro, y ~ .

Ol <'a; ,'$ R-bkiW, n jk C. M. Stallings Vice President-Power Supply and Production Operations Enclocure cc: Mr. Robert W. Reid 39 copies SR-SI-75-07 13644 0403090367 7511pg gDRADOCK 05000280

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SPECIAL REPORT I

s SR-SI-75-07 i

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. INADVERTENT BENDING OF

! CONIROL ROD DRIVE SIIAFT t

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DOCKET NO. 50-280 -

LICENSE NO. DPR-32_

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! NOVFlfEER 20, 1975 4

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j . SURRY__ POWER STATION .

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' VIRGINIA ELECTRIC AND POWER COMPANY -

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1. INTRODUCTI O!!

On October 25, 1975, Unit No.,1 was in the refueling chutdown condition following fuel movement and replacement of the upper internals package. The manipulator crane was being moved in preparation' for latchityg the full length control rods. During this movement the manipulator outer mast was inadvertently driven into the upper internals pachage, and damaged the drive shaft at core location P-8. The drive chaft was not latched to its control rod at the time of the impate.

11. SIRD*ARY OF OCCURRENCE Initial inspection of the drive shaf t indicated the impact resulted i

in a bend in the drive shaft. The drive shaft was removed from the guide tube for detailed televinion incpection and an evaluation was nade of the i

guide tube, gulde tube comba, RCC hub, comb welds, guide tube hold down I

bolts, " donut" hold down nprings, and the rod itccif. Details of the evaluation are as followu:

(1) Inspectien of the guide tube and RCCA revealed no evidence of obstruction in the guide tube hub and RCCA vane guide path and no apparent damage to the RCCA hub and vane.

(2) Measured friction drag forces throughout the full (145 inch) travel range of the P-8 drive line were within the normal range and were consistent with the t'orces measured at other core locations.

(3) The removabic incert was inspected, dressed and refitted.

No difficulties were encountered in removal or replacement operations. Iland manipulation after installation indicated no loosenesa.

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(4) The integrity of the upper guide tube hold down cap ccrews '

war. verified by viAual and physicial examination.'

(5) Straight edge meacut enents catablished that the top vertical west and couth faces of the P-8 upper guide tube were minutely displaced. This minor displacement , however, does not osces-sarily reflect the displace lnent of the guide tube centerifuc.

1od drop tests will verify thin shift does not interfere with I rod taotion.

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III. _CONCI.US10NS Based on a review of the examinations and tests performed on the , . . ,

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P-8 drive' 1inc, it has been concluded that the drive line (guide tube asocmbly a6d RCCA) is acceptable for reuse. Controlledtcbtshavebeen conducted in the teactor veidor'n tent loops which. Indicate that guida .

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tube misalign:aent of this magn [tude will not have a signif f' cant pf fect on drive line operation and drop ti:ics. The nucicar steam supply system manufacturer, the Westinghouce Electric Corporation, has reviewed the

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matter and concurs that the continued use of the component vill not significantly affect the operativ;: of the system.

Au final assurance of the adequacy of the P-8 drive line, an extensive rod drop test program will be conducted on this rod prior to the r_cactor start-up. In addition, the drive line will be re-inspected [.

during the next refueling outage to assure that no abnormal wear is .

occurring. .

The occurrence reported herein did not affect the health and safety ofthegeneralp$blic. .

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