Study of steam, helium and supercritical CO2 turbine power generations in prototype fusion power reactor

Power generation systems such as steam turbine cycle, helium turbine cycle and supercritical CO2 (S-CO2) turbine cycle are examined for the prototype nuclear fusion reactor. Their achievable cycle thermal efficiencies are revealed to be 40%, 34% and 42% levels for the heat source outlet coolant temperature of 480 degrees C, respectively, if no other restriction is imposed. In the current technology, however, low temperature divertor heat source is included. In this actual case, the steam turbine system and the S-CO2 turbine system were compared in the light of cycle efficiency and plant cost. The values of cycle efficiency were 37.7% and 36.4% for the steam cycle and S-CO2 cycle, respectively, The construction cost was estimated by means of component volume. The volume became 16,590 m(3) and 7240 m(3) for the steam turbine system and S-CO2 turbine system, respectively. In addition, separation of permeated tritium from the coolant is much easier in S-CO2 than in H2O. Therefore, the S-CO2 turbine system is recommended to the fusion reactor system than the steam turbine system. (C) 2007 Elsevier Ltd. All rights reserved.