Neutron distribution influence on the thermal design of a nuclear fuel rod

The object of the present paper is to look into the thermal and thermoelastic state in a nuclear fuel rod with gap and cladding, including a neutron flux distribution deduced by diffusion theory. The steady state temperature and the thermal stresses in the rod are analytically determined solving a set of differential and integral equations, deriving from heat conduction and Hooke's law. The mathematical technique here utilized is based on the modified first kind Bessel functions theory; the solution presents a very compact and simple form. The results so obtained are related and a comparison is made with the analogous results deduced implying a constant heat source distribution in the fuel, i.e., neglecting the actual neutron flux distribution. Some numerical results are finally reported with reference to a common boiling water reactor and shortly discussed.