ML20084M225

AO 4-73-1:on 730411,during Initial Fuel Loading,Part Length Rod Control Cluster RS4 Damaged While Fuel Assembly L51 Was Raised from Horizontal to Vertical Position.Caused by Inadequate Clearance.Limit Switch & Mechanical Stop Moved

ML20084M225
Person / Time
Site:	Turkey Point
Issue date:	04/20/1973
From:	Schmidt A FLORIDA POWER & LIGHT CO.
To:	Oleary J US ATOMIC ENERGY COMMISSION (AEC)
Shared Package
ML20084M228	List: ML20084M225 ML20084M232
References
AO-4-73-1, NUDOCS 8306020051
Download: ML20084M225 (2)

Text

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Mr. John F. O' Leary, Director

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Directorate of Reactor Licensing *- If,k'b 't l(,b' K

~U. S. Atomic Energy Commission $

Washington, D. C. 20545 '4 A EC.1 f5 N8:43p'Ee f7/E $ w-Turkey Point Unit No. 4 Docket Number 50-251

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f'd twa z Abnonnal Occurrence No. 4-73-1 4 M RCC RS4 Damage During Fuel Loading

Dear Mr. O' Leary:

'Ihis report is submitted in accordance with Technical Specification 6.6.2 a. and in amplification of Mr. J. K. Hays' telephone notification to Mr. R. C. Lewis, Region II, Directorate of Regulatory Operations, on April 11, 1973, and my telegram to Director, Region II, Directorate of Regulatory Operation, on April 11, 1973.

During initial fuel loading of Unit 4, at 4:25 a.m. on April 11, 1973, Part Length Rod Control Cluster (RCC) RS4 was damaged while fuel assenbly L51 was being raised from the horizontal position to the vertical position in the Reactor Side Lifting Frame Assembly (Upender). Due to inadequate cicarance between the conveyor car (which contained L51) and the fuel transfer tube, the end of the RCC spider body contacted the upper flange of the tube during the raising of the Upender. The spider was bent (about 23 ) until it cleared the flange.

The immediate corrective action consisted of ceasing fuel loading operations and implanenting Operating Procedure 16008.1, Accident Involving New Fuel. Contain-ment was evacuated and containment ventilation isolated. Swipes of the top and sides of the RCC and the fuel assembly were taken. From the negative results of the swipes and a careful visual inspection, it was evident the fuel assembly had not ruptured and thus, there was no radiological hazard.

The damaged RCC was removed from the fuel assembly by lifting the RCC with the auxiliary hoist on the manipulator crane and a sling with the assanbly held vertically by the Upender. The fuel assembly was approved for use by Westinghouse fuel consultants on site. However, it was decided to return the fuel assenhly to the fabrication plant for additional assurance that the assenbly is safe for use.

The assanbly was loaded into the core upon arrival back on site April 18.

pb ) 3 8306020051 730420 PDR ADOCK 050002S1 S PDR 2G52

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. .Mr.* John F. O' Leary Page Two April 20, 1973 During the pre-operational checkout of fuel handling equipment, a dumy fuel assembly

. with a full length rod inserted was used to test all the fuel handling equiIrtent.

No clearance problems were noted during dummy operations, nor during the loading of the first four fuel asselblies (two source assemblies with source inserts and two full length RCC's). The spider on the part length RCC is 0.695 inch longer than the spider on full length RCC's. The bent RCC overlapped the transfer tube flange approximately 1/16 inch. This would indicate approximately 0.6 inch of clearance for the full length assenblies. This clearance was not measured during checkout of the fuel handling equipment. No clearance problems were encountered during Unit 3 initial core loading, even though both units were constructed to the same drawings.

Permanent corrective action has been accomplished. The limit switch which limits the travel of the conveyor car was moved 5/8 inch (the maximum possible change due to physical limitations) away from the transfer tube. The mechanical stop on the conveyor car (which ensures that the RCC is essentially full inserted) was moved to allow 3/8 to 1/2 inch clearance between the full inserted RCC and the stop.

In addition, the fuel assemblies are monitored by an operator with binoculars during initial upender lifting to ensure adequate clearance is available in every case. Fuel loading was continued with the revised settings without recurrence of the problem.

The health and safety of the public was not affected by this Abnormal Occurrence.

Very tmly yours, b'

A. D. Schmidt Director of Power Resources ADS:DWJ:pm cc: Norman C. Mosely, Director Region II, Directorate of Regulatory Operation U. S. Atomic Energy Comission Suite 218, 230 Peachtree Street, N. W.

Atlanta, Georgia Mr. G. A. Olson Edison Electric Institute 90 Park Avenue New York, New York 10016 Dr. James Coughlin J. W. Williams , Jr.

J. R. Bensen J. B. Olmstead W. H. Rogers, Jr. S. G, Brain G. E. Liebler Plant Supervisors J. K. Hays Plant Nuclear Safety Comittee C. E. Branning Documentary Files D. W. Jones e