1. General presentation

There are five main families of research reactors:

• Technological irradiation reactors such as Osiris in France, HBWR in Norway, Hanaro in Korea, JMTR in Japan, etc., which are mainly used for applied nuclear energy research;

• neutron beam reactors such as Orphée and RHF in France, HFIR and MURR in the United States, BER-II in Germany, JRR3M in Japan, etc., which use neutron diffraction for fundamental research, in particular to characterize the structures of condensed matter;

• critical models such as Masurca and Éole, Minerve, Isis in France, BR-1 in Belgium... designed to meet the need for qualification of neutron calculations and core physics. These are very low-power reactors [typically 5 kW, for neutron fluxes of the order of 10 ⁹ ...