The development of a fusion specific depletion interface code—FATI

•A new depletion code, FATI, has been developed for fusion applications.•The code has been benchmarked against another well tested/benchmarked code, VESTA.•The FATI code incorporates fusion specific features which are not present in current fission oriented depletion codes such as MONTEBURNS and VESTA.

Knowledge of nuclide burn-up within lithium blankets has a crucial part to play in the safety, reliability and feasibility of a fusion reactor. A new depletion interface code is presented called FATI (Fusion Activation and Transport Interface) which interfaces MCNP with FISPACT. The intended primary application of FATI is the simulation of nuclide burn-up within fusion reactor blankets. This paper describes some of the functionality of FATI and presents a comparison of percentage variation of the nuclide atomic densities, for a simple spherical blanket model, calculated by FATI and VESTA. The inventories of the two depletion interface codes differ by less than 1% for lithium and lead isotopes, while H and He isotopes differ by larger amounts due to variations in the methods used to model gas production in FISPACT and the PHOENIX burn-up codes.