Autonomous Robotic Rearrangement of Nuclear Fuel Pellets for Formation of Fixed Length Stacks

This paper present novel algorithms for automatic preparation of stacks of prescribed length of sintered UO 2 pellets. They are used for fabrication of fuel pins for use in Nuclear Reactors. This system was developed to cut down on manual operations during fabrication of nuclear fuel. The solution integrates three technologies: precise vision based measurement of pellets and stacks, intelligent pellet rearrangement algorithm, and robotic transfer of pellets. In this paper, we mainly talk about the intelligent and efficient algorithms that rearrange stacks to prescribed length (within a tolerance of ± 1mm) through exchange, addition or removal of pellets. These algorithms have been tested systematically in simulation using pellet length distribution of a batch of pellets used for assembling fuel stacks. Simulation results were verified on a real setup comprising a KUKA KR-6 robot and a conveyor carrying a fuel tray under a pair of line-scan cameras. This development is expected to reduce worker exposure to radiation and radioactive contamination, apart from making the process fast, accurate and reliable.