Russian fuel company Tvel, part of state nuclear corporation Rosatom, has begun decommissioning building 804 at the Angarsk Electrolysis Chemical diffusion plant, which has been idle since the 1990s.  The work is being done within the framework of the federal target programme "Nuclear and Radiation Safety in 2016-2020 and until 2030" (FTP NRS-2) under the project "Decommissioning of Building 2 (Building No. 802) and Building 4 (Building No. 804) at AECC". The two buildings housed gaseous diffusion uranium enrichment facilities but were shut down in 1987 and 1990 after Russia switched to gas centrifuge technology. Building 804 still has process equipment which has not been dismantled, including 15 large-size units of diffusion machines and inter-unit piping systems, as well as other engineering equipment and scrap metal (fragments of dismantled process equipment).

Decommissioning will involve dismantling and elimination of process systems, equipment, engineering utilities and building structures followed by rehabilitation of the building host territory. Two general contractor have been appointed to undertake the work - FSUE "Radon" and JSC UDC PEM. Funding is provided from the federal budget. The initial work will entail construction of a temporary site for radioactive waste management, the organisation of access roads, construction of temporary storage sites for general waste, and the creation of an additional physical protection perimeter. “After completion of the preparatory work, we will begin to dismantle the building,” said Dmitry Solovyov, head of the decommissioning project at UDC PEM. Building 804 will be taken out of service and rendered environmentally acceptable. All radioactive waste will be processed and transferred to a specialised organisation for final disposal. Work is expected to be completed by the end of 2019.