The gas-turbine modular helium reactor (Reprinted from Nuclear news, October 2003)

The gas-turbine modular helium reactor (GTMHR) couples a high-temperature gas-cooled reactor (HTGR) with a Brayton power conversion cycle to produce electricity at high efficiency. It is based on HTGR technology developed over the past 40 years that includes the design, construction and operation of seven HTGR plants. The GTMHR satisfies the Generation IV goals of passive safety, good economics, high proliferation resistance, and improved environmental characteristics including reduced waste and better fuel utilisation than the current generation of nuclear power plants. Because of its capability to produce high coolant outlet temperatures (at least 850degrees C with potential for still higher temperature), the modular helium reactor system can also efficiently produce hydrogen by high-temperature electrolysis or thermochemical water splitting. The technology embodied in the GTMHR concept has high potential, with modest further development work, to meet the requirements for the next generation nuclear plant (NGNP) demonstration project planned to be built at the Idaho National Engineering and Environmental Laboratory (INEEL). The NGNP objectives are to demonstrate passive safety, licensing of new nuclear plants, use of the Brayton cycle for high-efficiency electricity generation and use of high-temperature nuclear heat for production of hydrogen.