Depleted uranium hexafluoride, or uranium tailings are a side produce to the uranium enrichment process in making fuel for nuclear power stations. Several thousand tons of depleted uranium hexafluoride has piled up in Russia and in other countries and there are no long term plans for their further use, meaning uranium tailings are classifiable as radioactive waste. According to the Russian legislation radioactive waste is defined as those nuclear and radioactive substances for which no further use is envisioned.
Russian legislation forbids the import of pure radioactive waste. Nevertheless, uranium tailings are imported to Russia via a variety of contracts between Russian atomic energy agency Rosatom and the German-British-Dutch enrichment giant Urenco, the French Eurodif enrichment concern, and others.
The current contracts between Rosatom and the western enrichment firms are valid until 2009 for Urenco and 2014 for Eurodif.