Kinetic Fick’s Law and the Integral-Differential Method of Solving the Neutron Transport Equation

Abstract

An exact relation expressing the difference current and the derivative of the scalar neutron fl ux via a coeffi cient of proportionality is obtained. This relation is defined as the kinetic Fick’s law. It is shown that Fick’s law in the elementary theory of diffusion is a particular case of the kinetic law. The conventional criterion of the diffusion approximation is supplemented by a condition that expands the range of application of the diffusion approximation. The conceptual scheme of a method termed the integral-differential method of solving the transport equation on the basis of the kinetic Fick’s law is presented.