Development of the GT-MHR Turbo Machine

Abstract

The high-temperature gas-cooled reactor technology is the only nuclear technology capable of achieving coolant temperatures as high as 950 °C and at the same time ensuring safe and efficient production of electricity, process steam and hydrogen. GA in USA and OKBM in Russia started an independent research in this area in the 1990s. In 1995, OKBM in cooperation with GA started development of the GT-MHR design which combines a safe modular reactor and a power conversion unit based on the high-efficiency Brayton cycle. The power conversion unit in the GT-MHR design has integral configuration, with vertical arrangement of the turbo machine consisting of an asynchronous generator and a turbo compressor. Active electromagnetic bearings are used as supports. In order to select optimal technical solutions, the effect of the following factors on the design was considered: vertical or horizontal arrangement, submerged or remote generator with oil bearings, and different turbo machine rotor speeds. Application of electromagnetic bearings and diaphragm coupling between the rotors, integral arrangement of the turbo machine inside the power conversion system vessel, and use of helium as a coolant required performance of comprehensive analyses and experiments. For this purpose, the helium turbo machine technology demonstration program was developed and is currently being implemented. This technology demonstration program aims at validating the quantitative and qualitative characteristics of such turbo machine components as electromagnetic and catcher bearings, control system, computer codes, generator, diaphragm coupling, turbo compressor, etc. At the concluding stage of the technology demonstration program, a full-scale turbo compressor model will be tested at a helium test facility.