Russia’s Siberian Chemical Combine (SCC), part of Rosatom’s fuel company TVEL, said on 17 February that it had started to install the main equipment at the uranium-plutonium MNUP fuel fabrication / refabrication module under construction at the Experimental Demonstration Energy Complex (ODEK), being built as part of the Proryv (Breakthrough) project. Sites have been completed ready for installation of equipment for the production of pellets of mixed nitride uranium-plutonium fuel. Installation has begun of the main technological equipment in eight sections of the carbothermal synthesis line and the line for the production of nuclear fuel pellets.

The module for the production of dense MNUP fuel will be one of the key elements of the power complex, which will also include a 300 MW power unit with a fast neutron reactor BREST-OD-300, as well as a module for processing irradiated fuel. The Breakthrough project is aimed at creating a new technological platform to demonstrate a closed nuclear fuel cycle which will solve the problems of handling and storage of used nuclear fuel and radioactive waste.

It is planned to complete the installation of the main technological equipment at the fuel fabrication-refabrication module in 2021. During the year, construction and installation organisations will have to lay 165 km of power supply lines at the ODEK site, install ventilation systems on an area of ​​about 8,000 square metres and install 450 tons of technological equipment.

Also on 17 February, SCC and TsKBM JSC (part of the engineering division of Rosatom) signed a contract for the manufacture and supply of a refuelling complex for the BREST-300 reactor for loading and unloading nuclear fuel into the reactor core. The production, supply and supervision of the installation of steam generators for the reactor plant will be provided by Machine-Building Plant ZiO-Podolsk (also part Rosatom’s engineering division).

Most of the design and technical solutions for the BREST-OD-300 reactor plant itself and its main equipment are innovative and have not been previously used at industrial nuclear facilities. The equipment of the reactor plant must ensure operability during the entire service life under conditions of high temperatures, high fluxes of ionizing radiation, and with a heavy liquid-metal coolant. Structural materials must have high corrosion and radiation resistance, high temperature resistance to ensure the reliability and durability of equipment elements.

Unlike NPPs with VVER reactors, where refuelling is performed at a cooled reactor plant, at a power unit with a BREST-OD-300 reactor these operations will be carried out at the temperature of the liquid-metal lead coolant in the primary circuit of more than 400°C. Before the fuel assemblies are loaded into the core, they will be heated in a special chamber and placed in the core filled with a melt of lead coolant, in a heated state.

For the manufacture of equipment capable of ensuring trouble-free operation in extreme conditions, the enterprises of Rosatom have carried out large-scale preparatory work, including R&D, design and engineering, selection of unique materials, creation of models and test stands, modelling of processes.

“The peculiarity of the construction of all facilities of the Experimental Demonstration Power Complex in Seversk is that all the key equipment both at the power unit with the BREST reactor and at the nuclear fuel fabrication and reprocessing modules is absolutely unique and has no analogues in the world,” said TVEL President Natalya Nikipelova. “The Breakthrough project team has to solve non-standard tasks related not only to the management of the construction of unique facilities, but also to a large programme of scientific research required for technical design.”

Producing high-tech equipment for the reactor plant takes from three to five years, and installation of the main equipment should be completed in 2025. On 10 February, the Federal Service for Environmental, Technological and Nuclear Supervision (Rostekhnadzor) issued a licence to SCC for the construction of the BREST-OD-300.