Past, present and future reactor neutron research requirements at the Kernforschungsanlage Juelich in an international context

Since the early 1960s two research reactors, FRJ-1 (MERLIN) and FRJ-2 (DIDO), designed as multi-purpose facilities (design powers of 5 and 10 MW were increased to 10 and 23 MW in the early 1970s), have served a wide spectrum of uses, ranging from fundamental nuclear physics through medical research, materials testing, radiochemistry and isotope production to thermal and cold neutron scattering in condensed matter research. Technical developments in irradiation facilities and techniques applied on a large scale have frequently been carried over to other research reactors, especially those at Studsvik and Petten, in continuing collaborative programs. While the need for materials testing has declined as the nuclear power industry has become more and more established, there has been a continuous growth over the years in the importance of neutron scattering research. This growth has been stimulated also by the construction of the first cold neutron source in the Federal Republic of Germany at FRJ-2, together with an external neutron laboratory connected to the cold source by newly developed neutron guides. Several novel experimental techniques, such as small angle neutron scattering, neutron back-scattering and diffuse elastic neutron scattering, have been implemented at these neutron guides. These techniques have since become firmly established as valuable research tools also in other laboratories, especially at the high flux reactor in Grenoble. For many years there has been an active exchange of information and experience with universities and laboratories of neighbouring countries. In order to secure and possibly improve the supply of neutrons at the Kernforschungsanlage Juelich in the medium term future, refurbishment concepts for FRJ-2 are being studied which range from simple replacement of older parts to a complete exchange of the whole reactor block and use of a new core concept to improve the flux level as well as to reduce the high energy neutron contamination in the thermal and cold beams. (author). 12 refs, 4 figs