Russia’s Federal Service for Ecological, Technological & Nuclear Supervision (Rostekhnadzor) has issued a licence to the Siberian Chemical Combine (SCC – part of Rosatom fuel company TVEL)) for operation of module for fabrication and refabrication of nuclear fuel (MFR) at the pilot demonstration power complex (ODEK – Opitno Demonstratsionovo Energo-Kompleks).

The ODEK project is part of the Breakthrough (Proryv) project intended to demonstrate closed fuel cycle technology. It is based on the Brest-OD-300 lead cooled fast reactor supported by the (MFR) and a module for reprocessing irradiated fuel. The reactor is scheduled for grid connection in 2027; the MFR is planned for commissioning this year; construction of the reprocessing unit is planned for 2025-2026 for commissioning in 2030.

ODEK is a cluster of new nuclear technologies that has no analogue anywhere in the world. The single site will be capable of manufacturing and recycling the reactor fuel. An innovative mixed dense nitride uranium-plutonium fuel has been developed (SNUP fuel) for the Brest reactor. It is based on two key components – depleted uranium, which is a by-product of uranium enrichment for nuclear reactors, as well as plutonium extracted from irradiated nuclear fuel.

The use of depleted uranium does not pose any risks in terms of nuclear and radiation safety, consisting almost entirely of the stable uranium-238 isotope with a fissile uranium-235 content of about 0.1%. In natural uranium the uranium-235 content is 0.7%, which is enriched to up to 5% for use in conventional NPPs.

At the next stage, after receiving the appropriate permission of Rostekhnadzor to handle plutonium, the MFR equipment can be used to produce SNUP directly from the used BREST reactor fuel. The repeated recycling of SNUP fuel will expand the nuclear energy resource base. It will also use the accumulated reserves of depleted uranium which result from the enrichment process, which would otherwise need to be stored. This radically reduces the generation of nuclear waste and its activity.

Unlike classical nuclear fuel based on enriched uranium dioxide, SNUP fuel cannot be produced using standard technology and equipment. In addition to non-standard fuel composition materials, the use of radioactive plutonium extracted from used fuel is a key component. In order to prevent a high dose load on personnel, the production of the fuel is as automated as possible. Four technological lines will be used to produce SNUP at the ODEK complex.

These include a line of carbothermic synthesis of mixed uranium nitrides and plutonium; a line for making SNUP fuel tablets; an assembly line for fuel elements; and a line for the production line of completed fuel assemblies.

Used fuel from the Brest reactor will be sent for refabrication after processing. In this way this system will gradually become almost autonomous and independent of external energy supplies, except for depleted uranium from the stores of the enrichment plants.

The advantage of fast neutron reactors is their ability to effectively use secondary fuel cycle products (in particular plutonium) for energy production. At the same time, these reactors can produce more potential fuel, including plutonium, than they consume. They can also burn the highly active transuranic elements (minor actinides), which would otherwise constitute high-level waste.

The MFR is almost complete. Currently the equipment on production lines is being tested. In March, in a video-link to the international forum ATOMEXPO-2024 test launch of the carbon thermal synthesis line took place. Obtaining a Rostekhnadzor licence will allow for comprehensive testing of the equipment of all the fuel production lines.

Image courtesy of Rosatom