Neutron activation of a stable adsorbing species transported in a porous medium

The equations describing transport in a non-isothermal pore of a stable adsorbing species undergoing neutron activation and its radioactive activation product are derived for the situation in which both species exhibit the same physical and chemical behaviour. The analysis is based on the simple parallel circular pore model and is formulated for a single pore. The following transport mechanisms are considered: diffusion in the gas in the pore; laminar flow of gas in the pore; diffusion along the wall of the pore; and adsorption and desorption at the pore wall described by a Henry's Law adsorption isotherm. Solutions to the equations are derived and illustrated for three situations relevant to the release of nuclides such as sup(110m)Ag and 134Cs from HTR fuel assemblies. (U.K.)