Response matrix of square node with full symmetries

An abstract-response matrix based on incoming currents averaged over the half-surface of a two-dimensional square node is developed by applying symmetry theory. In this formulation the boundary conditions of incoming currents averaged over the surface of a node are reduced to those averaged over a half-surface. This refinement of the boundary conditions does not change the transmission probabilities of thermal neutrons, but increases substantially the probabilities of fast neutrons. (author)