Contaminated pipes due to system solution in nuclear facilities need to be decontaminated and inspected of contamination for recycling/disposal under clearance rule in Japan. However there are some issues, most of the small diameter pipes, e.g. less than 60mm outer diameter, are not measured internal contamination levels because inspection equipment is unable to enter inner surface of small diameter pipes. Consequently, we dispose of most of the small diameter pipes as radioactive waste. To determine the optimal splitting method, we investigated such as the splitting conditions, splitting mechanism, number of blades, and placement of blades. As a result, splitting device is optimized by the combination of shearing by one arrow-shaped blade and form-rolling by two disk-shaped knife blades. Therefore the splitting device is developed with those blades, whose characteristic is as below: - operate at high speed; - operate for long life; - few metal chips by splitting; - splitting surface is smooth. Our result shows this method for small diameter pipes establish both decontamination of inner surface and contamination inspection efficiently. Thus, we will challenge positively for disposal under clearance rule. In addition, it is also expected to reduce radioactive waste from the effect of volume reduction by split pipes.
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