The prototype neutron-kinetics code MYTMUS incorporating a new method - contour zoning

A new method, contour zoning, is being developed for a prototype three-dimensional finite-difference diffusion neutron-kinetics code, MYTMUS. The method divides the reactor core volume into irregular computational regions that approximate the volumes between the flux contours. Thus flux variations within each region are small, and the number of regions needed for a given accuracy is greatly reduced. The computational speed/accuracy trade-off can be adjusted by the choice of contour interval. Results from a limited number of trial runs made to assess the method show that useful accuracies can be achieved with computational speed increases of one or two orders of magnitude over the conventional regular-mesh finite-difference MYTMUS solution, and there is scope for further improvement