Russia’s AI Leipunsky Institute of Physics & Power Engineering (IPPE – part of Rosatom) in Obninsk has completed a five-year programme to deal with sodium metal from the BR-10 sodium-cooled fast neutron research reactor now being decommissioned. The reactor was closed in 2002 after 43 years of operation. Used nuclear fuel from the reactor is brought to a safe state using a two-stage technology developed by specialists of the Institute’s hot cell laboratory.
Roman Schepelev, chief engineer at IPPE said an original method had been developed combining vacuum management of sodium metal and alcohol treatment of its residues and oxidation products. The technology will prove useful in the future for decommissioning other sodium cooled reactors such as the BOR-60, BN-350, BN-600 and BN-800. The technology can be used to remove sodium not only from fuel assemblies but also equipment. The BR-10 will become a pilot demonstration centre for the development of technologies for decommissioning fast reactors, he noted.
First a vacuum system is used to remove sodium vapour from inaccessible emergency assembly areas, which is them deposited on copper oxide particles. Then assemblies are treated with alcohol including high temperature control of hydrogen in the gas phase.
The specialists have tested this method of collecting sodium using a solid-phase absorber that not only extracts the sodium but instigates chemical interaction tat result in sodium as a non-volatile oxide deposited on its surface. This avoids the spread of radioactive sodium in communications. The used fuel will be sent to production association Mayak for subsequent regeneration.
The BR-10 operated from 1959 to 2002 as a key facility for the development of fast reactor power plant in the USSR. It is now being decommissioned under the Federal Target Programme “Nuclear & Radiation Safety for 2016 – 2020 and for the period to 2035”.
Image courtesy of Rosatom
