Controlled neutron field system at niiar reactors

The metrological support system for neutron measurements at nuclear reactors has been developed on the concept of controlled neutron fields applicable to organizations having a group of reactors. A metrological classification is proposed for the fields and the relation between them and also for approaches to certification. This controlled-field system has been set up at the NIIAR reactors for use in nuclear materials research. Data are given on neutron fields at five reactors.