As part of a comprehensive project being developed by Rosenergoatom (part of Rosatom) to develop technological solutions for a high-temperature gas-cooled reactor (HTGR), full-size reactor components made of carbon-carbon composite material have been developed and manufactured.
During research that began in 2023, specialists from OKBM Afrikantov in Nizhny Novgorod (part of Rosatom’s Mechanical Engineering Division) studied the main properties of various types of carbon-carbon composite. OKBM Afrikantov also serves as the lead designer for the HTGR plant. It has already developed and approved the preliminary design and is moving toward the technical project phase.
At the Institute of Reactor Materials (IRM) in Zarechny in the Sverdlovsk region (formerly part of the NA Dollezhal Scientific Research and Design Institute of Power Engineering – NIKIET), reactor tests were carried out at temperatures up to 1300 °C as well as studies of the physical, mechanical and thermophysical properties of irradiated samples of carbon material. Based on the research results, carbon material based on standard carbon fabric produced was recognised as optimal for the manufacture of HTGR components.
The use of a carbon-carbon composite material, characterised by stable physical and mechanical properties in a wide temperature range (from room temperature to 1600 °C) and with high radiation resistance (including in aggressive environments, makes it possible to increase reliability and reduce the weight and size of reactor installations.
At the final stage, designers and technologists worked out industrial manufacturing methods and created full-size mock-ups of individual structural elements. These included a support element 1650 mm high (a set of which serves as a support for a graphite fuel assembly core) and a working element of the control and protection system (a long flexible structure assembled from separate sections each 500 mm high).
“It is important to emphasise that the development of the technology for manufacturing structural elements for the HTGR was carried out using industrial equipment available at the site of our technological partner, said Fedor Grigoriev, project curator at Rosenergoatom. “This will make it possible in the future to apply the experience gained not only for the manufacture of other structural elements for the HTGR, but also to use the technology in other innovative projects of the Russian nuclear industry.”
Russia is currently developing next-generation HTGR technology with a primary focus on large-scale hydrogen production. A key project is development of a NPP featuring four 200 MWt helium-cooled HTGR units. Russia’s HTGR design emphasises total domestic technology, avoiding foreign components. In early 2025, Rosatom’s Science Division launched a pilot-industrial line at Research Institute Scientific and Production Association (NPO Nauchno Proizvodstvennoe Obedinenie LUCH) to produce TRISO (TRI-structural ISOtropic) fuel pellets for the reactor.
