Modelling conceptual designs for nuclear reprocessing

New fuel reprocessing techniques are being researched and developed. Availability, reliability, maintainability and cost (ARMCO) modelling has been identified as important for any assessment studies of the new techniques. This article explains what is happening in ARMCO assessments and the development of computer modelling techniques for the evaluation of conceptual process designs. The fuel reprocessing procedure itself is first explained. The wide range of options for an assessment can be dealt with by constructing a simple generic model and then fitting in each option in more detail. The advantages of this approach are explained. Data bases used to enter details of the model are illustrated. The model can operate in two modes -analytical, in which time averaged output values are calculated from mathematical relationships defined in the program, or statistical in which the model is run in the same way as a real plant and output data is built up as items fail and are then repaired. (UK)