Document Type and Number:
Japanese Patent JPH0354800
Kind Code:
B2
Abstract:
Both an apparatus and process for providing a coolant flow path in the top former plate of the core of a nuclear reactor are disclosed. The apparatus of the invention generally comprises an elongated tool support member having a tool mounting means for detachably mounting various tools in the vicinity of the top former plate, and a clamp assembly for securing and positioning the tool mounting means over the plate. The apparatus also includes an ultrasonic transducer (or probe) for measuring the thickness of the plate, a rotabroach device having a feed and drive assembly for driving a pilot drill bit and a rotabroach bit toward the top former plate, and a piercing tool for removing the slug formed by the rotabroach bit. In the process of the invention, an alternate coolant flow path is provided in the top former plate by boring a plurality of holes therethrough. In the boring process, the ultrasonic transducer is first detachably mounted onto the tool mounting means in order to measure the thickness of the plate. Next, the ultrasonic transducer is replaced on the tool mounting means by the rotabroach device and a pilot hole is drilled through the plate. The pilot hole is then broached by a rotabroach bit which penetrates down to the last 0.030 in. of the plate. Simultaneously, metal chips and slivers are removed with a chip breaking and collecting system. Finally, the feed and drive assembly are replaced by a piercing tool which removed the slug of metal in the broached hole in "can-opener" fashion to minimize the amount of metal chips generated by the cutting.
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Application Number:
JP27502984A
Publication Date:
August 21, 1991
Filing Date:
December 28, 1984
Export Citation:
International Classes:
G21C19/02; B23Q9/00; G21C5/10
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