The design and development of a microprocessor based control system for an electric rail transport system
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Radioactivity and radioactive radiation are two scientific phenomena which man has always approached with great caution, if not fear. Radioactive radiation cannot be sensed by any of the human senses and experience has proved just how hazardous it can be to the human body. This caution is therefore by no means unfounded and through the years a set of standards has been derived as to what can be regarded as a safe dose to the human body. At the National Accelerator Centre radioisotopes are being produced by a chemical recovery process from targets which have been irradiated by a high energy proton beam. Targets are prepared by compressing salts, containing the elements to become radioisotopes, into tablets. The high energy protons collide with particles in the targets which give off radioactive radiation. The targets in their turn become radioactive and the isotopes that are produced from these targets are radioactive. The level of radioactive radiation is extremely hazardous and it is therefore impossible for any human being to come into close contact with any of the targets or isotopes. It is for these reasons that an electrical rail transport system was installed at the National Accelerator Centre to transport highly radioactive sources. The transport system links the two irradiation vaults to the two rows of hot cells, where the chemical recovery takes place, and to a well shielded storage area for storage of isotopes and radioactive waste. A transport system, performing tasks of this nature, must be, above all, extremely reliable. Secondly, commands entered by an operator to control the system, must be simple and straight forward. This thesis describes the control of the transport system at the National Accelerator Centre, including alI of its features, advantages and disadvantages.