FRM-II. A new reactor also for isotope production

In Garching near Munich the Technische Universitaet Muenchen is building the 'Forschungsreaktor Muenchen' (FRM-II), a new multi purpose research reactor which will be operated at 20 MW thermal power. Although the main task of this reactor will be to provide experimental setups for beam tube applications it will be equipped with a variety of irradiation facilities which will be available for interested parties from research institutes and industry. The main design feature of the FRM-II is its very small reactor core ('compact core'). The single fuel element will be cylindrically shaped. More precisely it will consist of 113 fuel plates being bent to involute shape and welded between 2 concentric tubes having an inner diameter of 118 mm and an outer one of 243 mm. The height of the fuel zone will be 700 mm. It will contain approximately 8 kg of high density uranium-silicide fuel with an U-235 enrichment of 93%. The reactor core will be cooled by light water. The fission neutrons will be moderated, however, within a heavy water tank surrounding the core. It is the most important advantage of this design that the maximum of the thermal neutron flux density will be located outside the reactor core within the moderator tank. Consequently it will be available for experimental purposes. Its numerical value was calculated to be 8x1014cm-2 s-1 for undisturbed conditions