Rosatom starts afterburning of minor actinides in a fast reactor

Rosatom starts afterburning of minor actinides in a fast reactor

During the scheduled refueling at the Beloyarsk NPP’s Unit 4, its BN-800 fast neutron reactor has been for the first time loaded with lead-test assemblies of uranium-plutonium MOX fuel also containing the so-called minor actinides, the most radiotoxic and long-lived components from irradiated nuclear fuel.

The loading of innovative fuel into the reactor core was approved by Russia’s authorized regulator Rostekhnadzor (the Federal Service for Environmental, Technological and Nuclear Supervision), which had confirmed its safe operation. The power unit has resumed operation after the refueling.

The three lead-test MOX bundles containing americium-241 and neptunium-237 were manufactured at Rosatom’s Mining and Chemical Combine in late 2023. They will undergo pilot operation at the BN-800 core during three micro-campaigns (approximately a year and a half).

“The next micro-campaign of the BN-800 reactor should experimentally confirm the possibility of minor actinides utilization at industrial mode. The possibility to eliminate minor actinides is an advantage of fast neutron reactors, which allows reducing the volume of radioactive waste from the entire infrastructure of the nuclear fuel cycle of NPP operation,” said Ivan Sidorov, Director of the Beloyarsk NPP.

According to scientists’ estimates, afterburning of minor actinides in closed nuclear fuel cycle would enable the radiation equivalence of uranium feedstock and nuclear waste to be isolated in only 300 years, i.e. 2,300 times faster (about 700 thousand years in open nuclear fuel cycle).

Rosatom starts afterburning of minor actinides in a fast reactor

The technology of MOX fuel fabrication, including the bundles with minor actinides, was developed by Rosatom’s Fuel Division (managed by TVEL JSC). For the project of manufacturing the MOX bundles with minor actinides applying the common in-house technology and the regular industrial-scale equipment, Rosatom engineers had verified and validated 38 techniques for analytical control of the nuclear fuel properties.

“The bundles of MOX fuel with minor actinides, manufactured for a commercial large-scale fast reactor, are absolutely unique. This demonstrates the fundamental technological possibility to accomplish the most important component of generation-IV nuclear power systems.

The service of minor actinides afterburning in nuclear fuel for fast reactors is a completely new product for the global nuclear industry. Uranium-plutonium fuel itself enables to expand the feed-stock base of the nuclear power industry, to recycle spent nuclear fuel instead of storing it, and to reduce the volume of nuclear waste.

Further on, utilization of minor actinides is also an opportunity to significantly reduce radioactivity of the waste, which would enable in the future to abandon its complicated and expensive deep burial,” said Alexander Ugryumov, Senior Vice President for Research and Development at TVEL JSC.

Russia is now the only country developing a complete Generation IV power system based on the closed nuclear fuel cycle technologies. In Seversk, West Siberia, Rosatom is building the Pilot Demonstration Energy Complex, including the power unit with the BREST-OD-300 fast reactor, the unit for nuclear fuel fabrication/refabrication, and the unit for irradiated fuel recycling.

Fast neutron reactors can be fueled not only by enriched uranium, but also secondary products of the nuclear fuel cycle, such as depleted uranium and plutonium extracted from spent nuclear fuel. The so-called afterburning of minor actinides in a fast reactor is the next step of the Russian nuclear industry in closing the nuclear fuel cycle.

Under the influence of fast neutrons, they will be divided into elements that pose a much lower potential danger.
Today, the Beloyarsk NPP is testing the elements of the future technology, as the new higher capacity fast reactor is being designed.

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