Manufacturing and supply of a mercury cooled rotary uranium target for the GELINA accelerator facility of IRMM

AREVA CERCA* is a manufacturer of Uranium fuel elements for Research Reactors, Mechanical Components for nuclear industry and Radioactive Reference Sources for nuclear industry and medicine. The GELINA high-resolution neutron time-of-flight measurements facility of IRMM operates with a very special Uranium target. There is no other neutron production target in the world that has the same or even similar characteristics. Over more than two decades, AREVA CERCA developed and manufactured the rotary Uranium targets for the GELINA facility of IRMM. The use of Uranium and the induced activation during operation in GELINA ask for extremely reliable equipment, responding to very high safety demands. For the fabrication of the target, the very high quality control standards applicable for the fabrication of nuclear equipment must be applied. The material of the Uranium-molybdenum disk must fulfil very restrictive conditions. The target core of the target is cooled by a stream of Mercury, pumped by an electromagnetic pump manufactured by AREVA CERCA. Temperatures in the Uranium disk must be measured with thermocouples distributed inside the Uranium core, at the Uranium/cladding interface and at the inlet and outlet of the Mercury. The target has to rotate between an upper and a lower neutron moderator with very severe geometrical tolerances. The very small gap between the Uranium and the cladding must be filled with Helium before sealing. Preparation and installation of the Target at the GELINA linear Accelerator is presented. Performances and reliability of the targets are reported combined with major experiences and results gained by IRMM.