Two-dimensional four-group calculation based on partial buckling

A polynomial expression is proposed as a method of representing the distribution of neutron flux where the multi-group diffusion equation is machine-computed: A given system is divided into several sections that are fairly large compared with the mesh sizes usually adopted in calculations using difference equations. One reason why the polynomial is useful is that no change is required for its fundamental formation to accord with varying geometric factors such as the shape of the section and buckling of the flux distribution. The treatise presents a two-dimensional analysis, using the polynomial expression and the concept of partial buckling, introduced to substitute boundary conditions calculated from the flux distribution of the system. The potential applications of the analysis based on partial buckling are discussed on the basis of the results of two dimensional calculations on a system having a square cross section, in which the distribution along the X-axis is calculated with a difference equation, and that for the Y-axis is obtained from partial buckling. (author)