High-temperature gas-cooled reactors

Currently, nuclear power based on pressurized water reactor technology holds a worthy place in the sphere of power generation. The development of fast reactors ensures a more stable position of nuclear power in this sphere. Meanwhile, more than 60 % of all fuel resources are used in industry to produce process heat, in transport as fuel for engines, and for municipal heat supply.

Expansion of the nuclear power market in the "non-electrical sphere" is possible through introduction of high-temperature gas-cooled reactors. The design features of these reactors make it possible to obtain helium coolant temperatures up to 950°C, which has been proved by experience of operating foreign gas-cooled reactors.

Such a feature allows this heat to be used in various industries (chemistry, petrochemistry, oil refining, stimulation of viscous oil production, metallurgy, etc.).

High temperature allows production of hydrogen from water as fuel for transport and as a chemical reagent in industry.

Implementation of a direct gas-turbine cycle with high efficiency (about 50%) and parallel use of waste heat for municipal heat supply is considered advanced.

Afrikantov OKBM JSC has been developing high-temperature reactors for over 40 years. The company has conducted a considerable amount of research and development works, and over 70 test facilities have been created in cooperation for validating the HTGR designs. 

In cooperation with Russian companies, a number of HTGR designs of various purposes and power levels have been developed: the VG-400 nuclear station for combined generation of process heat and electricity in a steam-turbine cycle, the VGM modular reactor to generate process heat up to 900°C and electricity, the VGM-P nuclear station to supply power to a standard oil refining combine, the GT-MHR high-temperature modular reactor with a closed gas-turbine cycle for generation of electricity, the modular HTGR for process application of the MHR-T. The research supervisor of the designs is NRC Kurchatov Institute. Modern high-temperature gas-cooled reactor designs have a power unit of up to about 600 MW.

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Large test facilities are used to test unique equipment


Safety and high temperatures at the reactor outlet are ensured through the following:

  • inert, non-activatable helium coolant;

  • fuel based on spherical fuel particles with multilayer heat- and radiation-resistant coatings that reliably contain fission products in all operating modes, including emergency ones;

  • negative feedbacks as regards fuel temperature and power;

  • graphite-based heat-resistant structural core and reflector materials.

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The flexible fuel cycle of the HTGR technology allows the use of uranium-, plutonium-, thorium-based fuel, including MOX, without changing the core design, and ensures deep fuel burnup. Deep burnup excludes the possibility of using the filling of a fuel element for military purposes.

The HTGR can have a core based on prismatic fuel assemblies with refueling outages or ball fuel assemblies capable of being refueled without decreasing the reactor power.

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Spherical coated fuel particle

Scope of HTGR Application

  • Power-and-Process Applications

    Heat supply to production processes in various power-consuming industries. Transition to environmentally clean hydrogen power industry and “hydrogen economy.” The HTGR-based nuclear hydrogen concept is more effective than other technologies in meeting the challenges of large-scale fresh water production. The exceptional properties of hydrogen provide it with a wide perspective of applications in various fields of energy, transport, and industry.

  • Power Generation

    Highly efficient power generation through combining the HTGR with the gas- or steam-turbine cycle of supercritical parameters with a steam temperature of up to about 600°C. Electricity production efficiency up to 50% for small and medium capacity consumers.

  • Cogeneration

    Joint electricity and heat generation. A wide range of power generation and utilization options bring the HTGR thermal utilization factor closer to 100%.

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HTGR application options

Small-Sized HTGR Application Options

A reactor and a gas-turbine unit with a helium turbine arranged in a single unit can be used as compact autonomous power sources for surface, submarine, and hard-to-reach onshore facilities separated from the external infrastructure.

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Autonomous power source for submarine and hard-to-reach onshore facilities

  Main technical characteristics of a subglacial NPP with an HTGR for the Arctic region:

Characteristics Value
Net unit power, MW 8–25
Deployment depth, m             up to 400
Assigned service life (total), years 30
Assigned service life until factory repair, years 15


Example of layout of a subglacial rig unit for power supply in the Arctic environment

The main competitive advantages of the HTGR NPP are effective electricity generation, complete autonomy, and long-term operation without personnel and without refueling.

OKBM’s Experience in the Area of the HTGR

State program for nuclear hydrogen energy   

OKBM NRC Kurchatov Institute VNIPIneft

Rosenergoatom  Agreement
VG-400 VGM
(modular type)
(modular type)
(modular type)
(modular type)
Year 1987 1989 1996 2004 2002
Purpose Heat and electricity generation for commercial production Heat and electricity generation for commercial production Heat generation for an oil refinery Hydrogen and electricity generation Electricity and municipal heat generation
Heat power, MW  1,060 200 215 600 600
Intermediate circuit coolant Helium Helium Helium Helium
Helium temperature at the core outlet,°C 950 950 750 950 850
Status Detailed design Detailed design Technical proposal Technical proposal

Preliminary design.    Developing of key technologies

The engineering solutions underlying the HTGR and GT-MHR projects are legally protected, and today Afrikantov OKBM JSC has the rights to:

  • 1 invention,

  • 9 computer programs,

  • 1 data base,

  • 41 production secrets (know-hows).