Manufacture of vertical cold source SFV4

Neutrons are supplied to the experimental areas of the Institut Laue-Langevin (ILL) in Grenoble through horizontal or inclined channels integrated into the reactor block. Inside these channels, the neutrons flow through beam tubes, which begin in the reactor block and end in the experimental hall. The reactor is equipped with 12 horizontal and 4 inclined beam tubes. The vertical cold source, referred to also as "SFV4", enables a volume of 25 litres of liquid deuterium (at 24 K) to be maintained inside the reactor's heavy water reflector tank, thus providing a supply of cold neutrons for the ILL scientists. This is a cryogenic installation by design. The different volumes are thermally insulated by a secondary vacuum. Given the energy deposited by the nuclear flows, the installation is designed to undergo minimal heating, allowing a significant quantity of frigories to be received whilst optimising the production of neutrons. The location of the installation in the reactor requires a system of biological shielding. One part of this is the vessel filled with light water inside the cold source. As part of its reactor maintenance programme the ILL is now planning for the complete re-manufacture of the vertical cold source. A technical specification is to be issued for the operation.