License for world’s first production line of uranium-plutonium nitride (MUPN) fuel

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An operating license for the world’s first production line for the innovative mixed uranium-plutonium nitride (MUPN) fuel has been obtained by the Russian state atomic energy corporation Rosatom, the company announced late last month.  

Rosatom’s fuel arm TVEL had announced in 2021 that at the Siberian Chemical Combine in Seversk, Russia, it was constructing a 300 MW nuclear power unit equipped with the BREST-OD-300 fast neutron reactor that will run on mixed uranium-plutonium nitride (MNUP) fuel specially developed for this facility. 

TVEL had also announced it had developed a fuel rod design based on the MNUP fuel for the BREST-OD-300 fast neutron reactor.  

“Rosatom has obtained an operation license for the world’s first production line for innovative mixed uranium-plutonium nitride (MUPN) fuel,” a release said.   

Both the fuel fabrication and the reactor units form part of the Pilot Demonstration Energy Complex (PDEC) being built at the Siberian Chemical Plant by TVEL. The PDEC is underway as part of the strategic “Proryv” (‘Breakthrough’ in Russian) project. It will include three linked facilities, making up a closed nuclear fuel cycle at one site — the fuel fabrication/re-fabrication unit, the 300 MW nuclear power plant with the fast neutron BREST-OD-300 reactor, and the unit for spent fuel reprocessing.   

According to TVEL, “after reprocessing, the irradiated fuel from the reactor will be sent for refabrication (that is, reproduction into fresh fuel), thereby giving this system the means to gradually become practically autonomous and independent of external resources supplies”.    

The nuclear power industry’s resource base will practically become inexhaustible thanks to the infinite reprocessing of nuclear fuel. At the same time, future generations will be spared the problem of accumulating spent nuclear fuel.   

According to the International Atomic Energy Agency (IAEA), the fast neutron reactors operating in a closed fuel cycle could generate a circular economy in the energy sector based on the high-level nuclear waste generated by nuclear power plants.  

“Fast neutron reactors, which use neutrons that are not slowed by a moderator such as water to sustain the fission chain reaction, offer advantages over existing thermal nuclear reactors,” the IAEA said. 

“When operated in a fully closed fuel cycle, in which nuclear fuel is recycled and reused, fast reactors have the potential to extract 60 to 70 times more energy from the same amount of natural uranium than thermal reactors, thereby significantly reducing the amount of high-level radioactive waste,” it added.  

“When using fast reactors in a closed fuel cycle, one kilogram of nuclear waste can be recycled multiple times until all the uranium is used and the actinides — which remain radioactive for thousands of years — are burned up. What then remains is about 30 grams of waste that will be radioactive for 200 to 300 years,” says IAEA’s Head of the Department of Nuclear Energy, Mikhail Chudakov.  

Five fast reactors are currently in operation – two operating reactors (BN-600 and BN-800) and one test reactor (BOR-60) in Russia, the Fast Breeder Test Reactor (FBTR) in India and the China Experimental Fast Reactor. The European Union, Japan, the US, the UK and others have fast reactor projects underway that are tailored to a variety of aims and functions. 

The world’s most powerful fast neutron reactor called the BN-800, currently operating at unit 4 of the Beloyarsk nuclear power plant (NPP) in Russia, is powered by the MOX fuel made of depleted uranium and plutonium oxides. The BN-800 fast neutron reactor is designed to use MOX fuel as one of the stages in the development of a closed nuclear fuel cycle.   

The capacity of the Beloyarsk Unit 4 exceeds that of the world’s second most powerful fast reactor – the 560 MW BN-600 Beloyarsk Unit 3. 

According to TVEL “distinct from traditional nuclear fuel with enriched uranium, MOX fuel pellets are based on the mix of nuclear fuel cycle derivatives, such as oxide of plutonium bred in commercial reactors, and oxide of depleted uranium which is derived by defluorination of depleted uranium hexafluoride (UF6)”. 

Rosatom officials say the company is planning to set up a series of 1,200 MW (BN-1200) fast breeder reactors and the first one is expected to be connected to the grid in 2032. Once the BN-1200 starts functioning successfully, Russia will offer the technology of these largest fast breeder reactors to other countries. 

According to Rosatom, it is hopeful of getting the BN-1200 design approved by the regulators next year and start construction in 2026 as part of the Beloyarsk NPP. 

“The BN-1200 reactor will be a generation 4 sodium-cooled reactor. The design is ready and regulatory approval is expected in 2025. The plant construction will begin in 2026 and will be connected to the grid in 2032,” said Andrey Smelov, Leader of the Technological Team for the construction of the BN-1200 unit. 

According to the First Deputy Chief Engineer of the Beloyarsk NPP, Ilya Filin, the combination that works best is of a fast breeder reactor and a group of conventional, light water reactors of the kind at the Kudankulam NPP in India.  

“You can take the spent fuel from the VVER light water reactors, reprocess it and put it into the BN fast breeder reactor. And then, you can take the fuel bred at the fast breeder reactor and put it into the VVER. This reduces the need for parent fuel in the VVERs,” Filin said.   

The BN-600 fast breeder reactor at Beloyarsk unit-3 was built in 1980 and in 2010, it was modified to give it an extension of life till 2040. The fourth unit, BN-800, went on stream on December 10, 2015. 

According to Filin, “the BN-1200 reactor will be the first in the world of its size.” 

The BN-1200 would produce 1.15 times more fuel than it consumes, in contrast to the BN-800, which has a “breeding ratio” of 1. The Rosatom official said that in fast breeder reactors, the bigger size makes for better economics.