23 New Generation Reactors

In 1999, an international collaborative initiative for the development of advanced (Generation IV) reactors was started. The idea behind this effort was to bring nuclear energy closer to the needs of sustainability, to increase proliferation resistance, and to support concepts able to produce energy (both electricity and process heat) at competitive costs. Six reactor concepts were chosen for further development: the sodium fast reactor (SFR), the very-high-temperature gas-cooled reactor (VHTR), the lead or lead-bismuth cooled liquid metal reactor, the helium gas-cooled fast reactor, the molten salt reactor (MSR), and the super critical water reactor. In view of sustainability, the Generation IV reactors should not only have superior fuel cycles to minimize nuclear waste, but they should also be able to produce process heat or steam for hydrogen production, synthetic fuels, refinery processes, and other commercial uses. These reactor types were described in the 2002 Generation IV roadmap. Different projects around the world have been started since that time. The most advanced efforts are with reactors where production experience already existed. These reactors include the SFR and the VHTR. The other reactor types are still more in a design concept phase. This chapter briefly describes the six Generation IV concepts and then provides additional details, focusing on the two near-term viable Generation IV concepts. The current status of the applicable international projects is then summarized. These new technologies have also created remarkable demands on materials compared with light water reactors (LWRs). Higher temperatures, higher neutron doses, environments very different from water, and design lives of 60 years present a real engineering challenge. These new demands have led to many exciting research activities and to new Codes and Standards developments, which are summarized in the final sections of this chapter.