A brief overview of the research reactor FRM II
The research reactor Forschungsneutronenquelle Heinz Maier-Leibnitz (FRM II) is operated using a single compact fuel element embedded in a large heavy water filled moderator tank. Consequently the thermal neutron flux density exhibits its maximum value outside the fuel element in an area which is accessible for experimental installations. A further advantage of the use of heavy water is that it results in a very high ratio of thermal/fast neutron flux density, which offers ideal conditions for most irradiation experiments. In order to attract not only scientists but also commercial customers, FRM II operates, among standard irradiation facilities for activation analysis or isotope production, a semi-automatic Si doping facility for ingots up to 200 mm in diameter and 500 mm in height and a wide range of target resistivities between 20 Ωcm and 1100 Ωcm. Due to the still-growing demand for neutron transmutation-doped silicon, a total amount of approximately 4000 kg Si was irradiated already in the first year of operation. Another application which merits special attention is the therapy of mainly skin and throat cancer by means of fast neutron irradiation. Starting in 2007 the first human patients were treated in FRM II.
Keywords: reactor design, neutron irradiation, silicon doping, cancer treatment, research reactors, heavy water, skin cancer, throat cancer, fast neutron irradiation, nuclear energy, nuclear power