The Feinberg-Galanin method for heterogeneous reactors isformulated by using a two-group model instead of an age kernel. This treatment is then extended to take into account secondary effects such as fast liasion and thermalization of neutrons inside a rod which may contain moderator. The use of single coefficient in a Feinberg-Galanin approach allows one to relate the source and sink strength of the fuel element to the thermal flux only. By defining a set of four coefficients it is possible to connect the strengths ofthermal and fast neutron sources and sinks to both thermal and fast fluxes. A method of calculating these four coefficients α1, β1, α2 and β2 is presented.
The critical fuel mass of liasion electric cell reactor is calculated by using the four coefficient method. A value of approximately 0.77 kg is obtained, compared to a critical mass of 1.3 kg estimated from two-group homogeneous theory.
