The determination of the time evolution of the radioactive inventory in a material subjected to irradiation is a major challenge. It is ruled by a system of thousands of differential coupled equations. Excepting very few limited cases based on approximations, no analytcail solution to the system is known. Consequently, numerical solutions to the systems have been developed and implemented in computational tools in last decades for fission or fusion specifics. ACAB is one of them, considered as the one of the most recognized tools.

Thus, ACAB is a code for the determination of the time evolution of the radioactive inventory and the related quantities. It allows to determine the activity, the contact dose rate, the decay photon source, and waste management related indexes. ACAB deals with activation by neutrons, light particles and photons. Continous or pulsed irradiatio scenarios can be treated

ACAB code is in development since 1990 first at UPM, later at UNED. It consists on an adaption of ORIGEN code, developed by ORNL fission applications, to deal with the fusion particularities. ACAB has been benchmarked under auspicies of the International Atomic Energy Agency and the Department of Energy of the US. In both cases, ACAB was one of the sole two codes with positive results. Afterward, it was used as the reference code for the desing of the National Ignition Facility (NIF) in the USA. ACAB is distributed by the Nuclear Energy Agency with free licensing.

Further information of ACAB can be found in the following documents: