Existence of the solution for optimum reactor core region selection

Full text: Thermal-hydraulics calculation of the reactor includes calculation of the flow distribution, quality and content of vapour radial distribution. Since the neutron flux distribution can be described by Bessel functions, the generated heat spatial distribution can be described by the same function in case od cylindrical geometry. Relevant radial variation of coolant flow per channel is needed. Ideal calculation would deal with local relations but this approach would be complicated and technically not justified. Optimum solution would be dividing the reactor core into thermal zones. Adequate choice of zones should be done under condition of optimum discrepancy of the zone-wise local flux from the mean flux. In this way the step-function distribution would be the best approximation of the local zone-wise distribution. The analysis of the mentioned condition showed that it is fulfilled if the mean generated power in two zones is equal to local power generation on their common boundary