UOC is transported worldwide from the mining areas to conversion
plants located in North America, Europe and Russia. It is first
chemically purified and then converted by a series of chemical
processes into natural Hex, which is the form required for the
following enrichment stage. The natural Hex produced from the
conversion of UOC is a very important intermediate in the
manufacture of new reactor fuel. There is a very large commercial
trading in it that involves international transport.
In the production process, large cylindrical steel transport
cylinders some 1.25m (48") in diameter, each holding up to 12.5
tonnes of materials are filled directly with Hex which can be
liquid or gaseous depending on the manufacturing process. The Hex
then solidifies inside the cylinder on cooling to room temperature.
In storage and during transport the Hex material inside the
cylinders is in a solid form. Natural Hex is also stored in these
cylinders prior to being transported to an enrichment plant. Hex is
routinely transported by road, rail or sea, or more commonly, by a
combination of modes.
Although Hex is a low specific activity material there would be
a chemical hazard in the unlikely event of a release because it
produces toxic by-products on reaction with moist air.