Nuclear fusion has the potential to become a source of safe, non-carbon emitting and virtually limitless energy, recreating fusion reactions as they happen in the center of our sun. Several experiments around the world aim at building and operating fusion reactors that can create more energy than it needs to power them. The extreme conditions in such reactors pose particular challenges to the materials used and to the supplying industry.
One key factor in current and future fusion reactors is to maintain excellent vacuum conditions in the central vacuum chamber housing the fusion reaction. For this, one relies on cryogenic vacuum pumps that exploit a phenomenon we all know from our daily life: Take something out of the freezer and you will immediately see how air humidity will condense on the cold surface. Cryogenic vacuum pumps push this principle to the extreme: They capture gaseous components by freezing them onto a surface cooled close to absolute zero at around -273 °C.
RI, together with its consortium partner Alsyom, France, has taken up the challenge to manufacture these crucial components for the next generation of experimental tokamak instalments: ITER in Cadarache, France, and JT-60 in Naka, Japan.
Within the consortium, Alsyom takes over the production of the massive flange and shell components. RI will produce the heart of the cryopump and will be also resonsible for the complex assembly work of the pumps. Among the components in production at RI are rectangular-shaped cryopanels measuring 1 m by 0.2 m, which will be cooled down to -269°C to trap the gas particles. In addition, several kinds of thermal radiation shields are also in production. They will function at about -193°C to prevent the cryopanels from heating. All the components are stainless steel and liquid helium will circulate through them to keep them cool.