And the engineering here is very problematic. Indeed, the issue mentioned may be a showstopper for DT fusion.
The problem is limits on power/area through the wall of the reactor. Because all the produced energy has to go through the wall, and because the area of the wall grows as r^2, the volumetric power density of a DT reactor (that doesn't exceed the power/area limit on the wall) must decline with increasing size.
This leads to DT fusion reactors having horrible volumetric power density. ITER, for example, has a volumetric gross fusion power density of 0.05 MW/m^3. The 2014 ARC design, 0.5 MW/m^3. A PWR's reactor vessel? 20 MW/m^3.
(If you look at the power density of the plasma alone, or the fission reactor core alone, you get similar wildly discrepant numbers: https://cpb-us-w2.wpmucdn.com/research.seas.ucla.edu/dist/d/... see slide 26)
If you want to make heat to make steam to drive a turbine, a fission reactor will be much smaller, and much cheaper, than a DT fusion reactor.
The problem is limits on power/area through the wall of the reactor. Because all the produced energy has to go through the wall, and because the area of the wall grows as r^2, the volumetric power density of a DT reactor (that doesn't exceed the power/area limit on the wall) must decline with increasing size.
This leads to DT fusion reactors having horrible volumetric power density. ITER, for example, has a volumetric gross fusion power density of 0.05 MW/m^3. The 2014 ARC design, 0.5 MW/m^3. A PWR's reactor vessel? 20 MW/m^3.
(If you look at the power density of the plasma alone, or the fission reactor core alone, you get similar wildly discrepant numbers: https://cpb-us-w2.wpmucdn.com/research.seas.ucla.edu/dist/d/... see slide 26)
If you want to make heat to make steam to drive a turbine, a fission reactor will be much smaller, and much cheaper, than a DT fusion reactor.