Evaluation of CO₂ emissions in the life cycle of tokamak fusion power reactors

Global warming is one of the most serious problems which human beings are currently facing. Carbon dioxide (CO₂) from power plants is considered one of the major causes of global warming. In the present study, CO₂ emissions from tokamak fusion power plants are compared with those from present power generating technologies. Plasma parameters are calculated by a systems code that couples the ITER physics, toroidal field coil shape and cost calculation. CO₂ emissions from construction and operation are evaluated by multiplying component volume by the CO₂ emission intensities of the component materials. The reactor building, balance of plant, etc., are scaled from the ITER reference power reactor (`ITER-like') by use of the Generomak model. The most important finding is that CO₂ emissions from fusion reactors are less than those from photovoltaic systems and less than double those from fission reactors. The other findings are that: (i) Most CO₂ emissions from fusion reactors are from materials. (ii) CO₂ emissions from reactor construction account for almost 60-70% of the total, with the rest coming from reactor operation. (iii) The reversed shear reactor can reduce CO₂ emissions by half compared with the ITER-like reactor. It is concluded that tokamak fusion reactors are excellent for their low CO₂ emission intensity, and that they can be one of the effective energy supply technologies to solve global warming.