Nuclear reactors used to produce radionuclides for medicine

The main tools for the production of radionuclides for medicine are nuclear reactors and accelerators especially cyclotrons and linear accelerators. About 30 reactors over the world share isotope production. Two types of reactors are used to produce radio-nuclides: experimental reactors and neutron source reactors. In a reactor, radionuclides are produced through either fission reactions or neutron activation reactions. For instance the Technetium-99 whose daughter isotope Molybdenum-99 is used in scintigraphy is produced through the fission of Uranium-235 target, its fission yield being over 6%. The most important experimental reactors having a radioisotope production program are HFR (45 MW, The Netherlands), BR2 (100 MW, Belgium), NRU (135 MW, Canada), MARIA (30 MW, Poland), LVR-15 (10 MW, Czech Republic), SAFARI-1 (20 MW, South-Africa) and FRM-II (20 MW, Germany). Neutron source reactors are less powerful a few MW and produce radionuclides through neutron activation reactions. In France 2 neutron source reactors produce radionuclides for medicine: the Orphee reactor (14 MW, at Saclay) and the RHF (58 MW at Grenoble). (A.C.)