A fifty-percent-efficient, combined-cycle MHTGR and the environment

The Commissariat a I'Energie Atomique and Framatome of France took part in recent international gas turbine modular high-temperature gas-cooled reactor (MHTGR) research work together with General Atomics, Gas-Cooled Reactor Associates, Oak Ridge National Laboratory, and the Massachusetts Institute of Technology of the United States; Siemens-KWU of Germany; and the Japan Atomic Energy Research Institute. The combined gas-steam cycle version has received particular investigative attention in Europe. Following several preliminary evaluations the presented concept can be considered to be a real advance for the following reasons: 1. The net plant efficiency reaches 50%. 2. The topping gas cycle is indirect, clearly separate from the primary circuit. 3. The intermediate heat exchange (IHX) transfers all the reactor heat, so there is no water-steam heating on the primary circuit. 4. The IHX is pressure balanced, and its temperature difference is convenient, which makes its design possible. 5. The environmental aspects are attractive