Coater requirements

NNL are seeking to place a contract for the design of a fluidised bed chemical vapour deposition system. The equipment should have a coating chamber diameter of around 150mm and be capable of coating 1-2 kg of 0.5mm diameter kernels of uranium dioxide (UO2) in a single batch. Each coating will need to be deposited from different precursors sequentially while at its operating temperature, ranging from 1200-1600°C. The expected precursors for the different coating layers are acetylene, acetylene/propylene mixtures and methyltrichlorosilane diluted in hydrogen. An argon carrier gas is also required for fluidisation. Due consideration will need to be given to the scrubbing of exhaust gases and to the safe operation of the equipment using these reactive precursors on a nuclear licensed site.