Nuclear fuel

JSC «VNIINM» is engaged in improving nuclear fuel for nuclear power plants with water-water 
reactors to increase the fuel cycle duration up to 18 months of operation and increase the 
installed design capacity of NPPs. The Institute also conducts work to substantiate the use of fuel 
in maneuvering modes of operation of nuclear power plants. 

JSC «VNIINM» develops fuel rods with uranium-plutonium fuel (REMIX and MOF) and fuel 
rods with uranium-erbium composition for operation in PWPR-600 and PWPR-1000 reactors. 
The use of uranium-plutonium fuel in PWPR reactors will make it possible in the future to 
switch to a closed fuel cycle and ensure the transition to a 24-month fuel cycle.

The Institute is a developer of calculation software (codes) required to substantiate the 
performance and safety of nuclear fuel. The codes make it possible to simulate its behavior in 
different operating modes. 

• the «Start-4A» code is designed for calculation of fuel element operation in the normal operation mode
• code «RAPTA-5.2» is designed for calculation of fuel element operation in the mode of design basis accidents

JSC «VNIINM» developed a fuel element design with a fuel pellet without a central hole and a thickened cladding, as well as performed design justifications of the developed design for TVS-Square - nuclear fuel for pressurized water reactors of Western design (PWR).

The studies of the fuel irradiated during four fuel cycles confirmed the safe performance of Russian-made fuel rods of TVS-Kvadrat fuel elements and also allowed to certify the design
codes.

JSC «VNIINM» in cooperation with industry enterprises and a number of Russian scientific organizations provides scientific and technological support for the development of fuel for high-temperature gas-cooling reactor (HTGR).

The HTGR is a helium-cooled graphite reactor that operates at 2 to 3 times the temperature of conventional reactors, but at a lower power density.

As part of the project implemented by Rosatom State Corporation to create a nuclear power plant, it is planned to create a complex of four units with a thermal capacity of 200 MW each. The heat removed by the helium heat carrier is transferred to the chemical and technological part of the complex, where hydrogen is produced. The capacity of the AETS will be about 440 thousand tons of hydrogen per year, with commissioning scheduled for the early 2030s.

JSC «VNIINM» is developing microspherical fuel and fuel compacts for HTGRs.This is a promising all-ceramic fuel in which nuclear materials are placed in microparticles (microtwels) with a diameter of about one millimeter, which have ceramic coatings and retain both solid and gaseous fission products well throughout the fuel cycle.

The unified microspherical fuel developed at the Institute can be used in HTGRs both with a core of graphite hexagonal blocks and in the backfill zone with ball fuel elements. Microspherical fuel is one of the safest and most reliable types of nuclear fuel, providing internal self-protection of the reactor. In accidents involving loss of coolant, fission products remain inside the microsphere fuel at temperatures up to 1600 °C.

JSC «VNIINM» is engaged in the development of fuel compositions and liquid salt reactor (LSR) radioactive waste management technology. In 2019, Rosatom started the development of Russia's first research LSR to test the technology 

for afterburning of long-lived nuclear energy waste - minor actinides. The LSR has the property of natural safety: its temperature and void coefficients are negative, which excludes severe accidents like Chernobyl. The core temperature is very high, about 700 °C, but there is no pressure in the circuit, which increases reactor safety.

At present, the Institute has created two unique facilities for testing various fuel operations. The first one is designed for production of fuel pellets by hydrofluorination of various actinides in lithium fluoride melt. The second one is designed to develop the technology of reductive extraction in liquid bismuth. This technology will be used in the spent fuel reprocessing module of the research LSR, which will process fuel salt, extracting fission products from it, and allows removing corrosion products.

JSC «VNIINM» develops nuclear fuel and structural materials for fast neutron reactors.

The Institute improves existing types of fuel and core construction materials for operating and designed fast neutron reactors with sodium coolant (BN-600, BN-800, BN-1200), as well as with heavy liquid-metal coolant (BREST, SVBR).

The fuel composition for fast reactors is mixed uranium-plutonium fuel in oxide (MOF) and nitride form (MNUPN) containing minor actinoids. The structural materials in this case are stainless ferritic and ferritic-martensitic steels, including those dispersion-strengthened with various oxides.

The use of MOF and MNUPN fuel makes it possible to involve depleted uranium into the  nuclear fuel cycle, gradually eliminating its accumulated stockpiles and to finish burning long-lived minor actinides extracted from radioactive waste. Improvement of the technology for fabrication of these types of fuel involves increasing the duration of the fuel campaign up to 24 months, increasing the efficiency and profitability of fabrication production, and improving radiochemical processing. 

In addition to manufacturing experimental fuel assemblies, «VNIINM» JSC conducts pre- and post-reactor studies and directly supervises reactor tests.

JSC «VNIINM» develops nuclear fuel for reactor units of nuclear icebreakers, small and floating NPPs. 

PJSC «MBP» started production of a new generation of fuel elements - cermet (ceramic-metal) fuel for nuclear reactors of various types. This type of fuel is used, among other things, at the Akademik Lomonosov PWPP and is also planned for small capacity nuclear power plants (SCNPPs).

«VNIINM» scientists have developed cermet fuel for the new-generation nuclear icebreakers Ural and Leader, the PIK research reactor, and modernized LPNPPs that will be built to power the Baimsky mining and processing plant in Chukotka and the Kyuchus gold deposit in Yakutia. The technical design of a fuel element for the Shelf-M small reactor is also in the works.

One of the activities of «VNIINM» JSC is the development of low-activated structural materials(with fast activity decay) for use in fast reactors of the third and fourth generations.

Low-activated structural materials are an important component of the implementation of the technology of the complete closed nuclear cycle, as they significantly reduce the impact on the environment due to their reuse (recycling) after neutron irradiation after a time not exceeding 100 years.

JSC «VNIINM» is developing technologies for the production of composite materials based on silicon carbide SiCf/SiC, which are potentially superior to metals in terms of heat and corrosion resistance. Such composites are used in aerospace and automotive industry, electronics,manufacturing of mirrors for telescopes, it is planned to use them in fusion reactors and fuel element cladding of thermal reactors as an alternative to zirconium alloys.

Ferrite-martensitic steels of grades EK181, CS139 developed at «VNIINM» JSC are promising materials of fuel element cladding for operation in fast neutron reactors BN-800 and BN-1200.These steels have high radiation resistance and have already been tested in FER-60 and BN-600 reactors.

Heat-resistant ferritic-martensitic chromium steel EP 823-Sh has become the main core material of BREST-OD-300 lead cooled fast reactors. This steel is also suitable for use in fuel element cladding with MNUPN fuel.

Alloy 42 CNM has found application as a material for fuel element cladding of nuclear icebreakers and absorbing rods of the PWPR control and protection system. In the future, the alloy may be approved for production of dispersion-type fuel element cladding for low-power nuclear power plants and tolerant fuel cladding for PWPRs.

Under the guidance of «VNIINM» JSC, the technology of production of cladding tubes and component parts for fuel rods with mixed uranium-plutonium nitride fuel is being developed, the effect of chrome coatings on zirconium alloy fuel rods cladding is being studied within the framework of increasing the safety of operation of tolerant ATF fuel.