Generation III+, IV, and fusion
New nuclear 10 February 2016
Light Water Reactors (LWRs) are Gen II commercial reactors, which were built for an operational lifetime of 40 years. Most of the nuclear reactors built in the 70s and 80s are commercial pressurized (PWRs) or boiling water reactors (BWRs), which are both LWRs. At present, 11% of the world’s electricity comes from these nuclear reactors, they are considered carbon neutral, i.e. they don’t release anywhere near as much carbon dioxide as fossil fuels. There are 440+ commercial nuclear power reactors operating in 31 countries, and about 65 more reactors are under construction. Nuclear reactors of generation III have a longer operational lifetime of 60 years with improved fuel technology, thermal efficiency, modularized construction, safety systems with passive features etc. There are many factors which are considered in the construction of nuclear reactors, safe operation is a fundamentally important factor, intrinsic to the design. The unfortunate Fukushima Daiichi nuclear disaster caused by loss-of-coolant, demands increased safety features in design of future reactors (In fact, the U.K originally declined to build this specific reactor type). The design of future Gen III+ and Gen IV nuclear reactors are aimed to be highly economical, with minimal waste generation and enhanced safety features.
The design and construction of future nuclear reactors will focus on active as well as passive safety features. The nuclear community is looking for future fusion rectors as well. Feasibility studies are being carried out to harness energy from fusion reactions as fusion power is promising inexhaustible source of energy. But it involves some of the most advanced plasma physics and reactor engineering challenges. International Thermonuclear Experimental Reactor (ITER) is a collaborative international project intended to prepare the way for the fusion power plants of tomorrow. ITER-Tokamak is being fabricated in Cadrache, France to study integrated technologies, materials’ performance, and physics regimes essential for the commercial production of fusion power.
In a nuclear renaissance era, we are likely to see environmentally friendly nuclear reactors with improved safety features.
Charu L Dube is a post doc at The University of Sheffield.
What about Liquid Thorium reactors?
Generation IV are reckoned to be either fast neutron or molten salt. A “Thorium reactor” does not necessarily mean LFTR. But the huge advantage of the MSRE, Molten Salt Reactor Experiment, was more the thermal spectrum Molten Salt, than the clever use of thorium as a feedstock to produce fissile uranium. There is even a design of Molten Salt Reactor the MCFSR at Elysiumindustries.com, which uses fast neutrons and IMHO could be classed as Gen V when its first prototype is working.
The advantage of thorium in a thermal neutron reactor is that its product U-233 is less likely to waste a neutron by capturing it without fission, than is the neutron capture product Pu-239 from U-238.
The neat thing about fast neutrons is that they eat everything actinoid.