A brief description of PROFESS and its sub-models

A computer code named PROFESS has been developed for the analysis of the irradiation behaviour of oxide fuel elements used in water cooled thermal reactors. PROFESS is an axisymmetric one dimensional code which incorporates semi-empirical models of material properties, irradiation induced phenomena and their mutual interactions. Major phenomena treated in this code include fuel densification, solid and gaseous swelling, fuel restructuring, fission gas release, fuel relocation and cladding creep. The input to the code consists of design geometry, fuel and cladding specifications, power irradiation history and the irradiation environment data. The output from the code includes fuel element diametral changes, gas pressure inside the fuel element, dimensional and microstructural changes in the fuel, composition of the gas in the fuel element, fuel temperature and fission gas release. This paper presents a brief description of PROFESS, models incorporated in it, the sequence of calculations. The paper also gives the results of verification of PROFESS against a few irradiation experiments. (author)