International efforts to measure, model and evaluate nuclear data for the minor actinides

Heavier actinides have generated interest in recent years because of their importance in the development of nuclear power plant in which the fuel will contain consistent and controlled amounts of such nuclides. These 'minor' actinides are identified with neptunium, americium and curium, and are produced as by-products within thermal reactors that burn 235U/239Pu fuel. As a consequence of their behaviour in the core with respect to neutron absorption, they and their decay products are major sources of radiation in spent fuel and reprocessing waste. Reliable and accurate neutron-induced cross-sections and decay data are required for the implementation of sound operational and high burn-up strategies. Thus, a series of Coordinated Research Projects have been launched by the International Atomic Energy Agency to assist in the resolution and elimination of nuclear data issues identified with the minor actinides, as described in this paper. (authors)