Nothing about the current tokamak based designs suggests they will be any cheaper to build for a given power rating than existing fission designs:
- They need large, highly advanced cryocooled superconducting magnets in very close proximity to a hundred million degree plasma. This only makes economic sense in massive, and expensive plants.
- They are a very strong source of fast neutrons useful to transmute cheap depleted uranium into plutonium, so carry massive proliferation risks, need close regulatory scrutiny and will require mounts of paperwork to operate, thus exceptionally inflexible to improvements and rapid iteration. Just like the current fission crop.
- Aneutronic fusion is a currently a purely theoretical concept, in the last 70 years nobody has been able to contain even the much cooler D-T plasma for economically viable durations and temperatures.
- The structure of the reactor becomes radiologically active and cleanup operations must be considered. Highly penetrating neutron radiation means some radiation will escape regardless of containment, requiring a radiological exclusion zone. No Mr. Fusion in your car, sorry.
- They operate and must breed sensitive nuclear materials - Tritium, a well known component of boosted thermonuclear weapons. The limited efficiency of tritium production from lithium-6 might require obtaining some from fission reactors to top up the fuel cycle and keep fusion reactors operating.
So when you draw the line, a life time of magnetic containment research has produced a speculative design that even if it were to work, which it doesn't, would be, in the best case scenario, comparable to existing fission designs that are being phased out for cost and risk issues.
A PhD money pit with zero chance of ever building anything useful.
- They need large, highly advanced cryocooled superconducting magnets in very close proximity to a hundred million degree plasma. This only makes economic sense in massive, and expensive plants.
- They are a very strong source of fast neutrons useful to transmute cheap depleted uranium into plutonium, so carry massive proliferation risks, need close regulatory scrutiny and will require mounts of paperwork to operate, thus exceptionally inflexible to improvements and rapid iteration. Just like the current fission crop.
- Aneutronic fusion is a currently a purely theoretical concept, in the last 70 years nobody has been able to contain even the much cooler D-T plasma for economically viable durations and temperatures.
- The structure of the reactor becomes radiologically active and cleanup operations must be considered. Highly penetrating neutron radiation means some radiation will escape regardless of containment, requiring a radiological exclusion zone. No Mr. Fusion in your car, sorry.
- They operate and must breed sensitive nuclear materials - Tritium, a well known component of boosted thermonuclear weapons. The limited efficiency of tritium production from lithium-6 might require obtaining some from fission reactors to top up the fuel cycle and keep fusion reactors operating.
So when you draw the line, a life time of magnetic containment research has produced a speculative design that even if it were to work, which it doesn't, would be, in the best case scenario, comparable to existing fission designs that are being phased out for cost and risk issues.
A PhD money pit with zero chance of ever building anything useful.