Optimization of BHWR. Description of Programmes and Applications

The paper describes optimization programmes developed for boiling heavy-water reactors of the pressure-vessel type. The programmes include several versions applicable to a direct or indirect steam cycle and forced or natural circulation in the core. Each programme consists of 15 to 18 independent variables and a number of physical limitations to give conditions acceptable from the aspect of fuel centre-line melting, burn-out, stability, etc. The main purpose of the programmes has been to develop a method for rapid assessment of .the influence of various assumptions on the optimum lay-out of a BHWR. The results of the optimization also establish a starting point for more detailed design studies. A brief description of the various parts of the programmes together with the applied minimization method is given. A complete optimization takes 10 - 20 min on an IBM-7044 computer. The programmes have been used in a number of special investigations such as the determination of the influence of the price of Pu on the optimum burn up, the comparison of direct and indirect cycle characteristics, etc. Examples of the results of some of these investigations are discussed. (author)