As mentioned in the previous post, there is a distinct difference between the timeline of the public fusion program and private fusion companies.
The difference in time scales is mainly a result of choosing different fusion reactor designs. The main public fusion program (the ITER route) has chosen a design called the “tokamak” and research is concentrated on getting that design to deliver fusion. By contrast, most private fusion companies have each chosen a different design, which they hope will deliver the same result, but sooner and at a lower cost.
The public fusion program had very good reasons to choose the tokamak; it was the most promising design in the 1960s. It quickly became evident, however, that the tokamak would have to be “large” to deliver efficient fusion. This need for size is (primarily) what is making the public fusion program very slow.
ITER is so large that it could only be built by an international consortium of countries, making it one of the largest international science programs in history. It is also one of the most expensive, with the total cost currently standing at over $20 billion. Large projects are almost by definition long (in time-duration) projects, and this is the primary reason why the public fusion program has slowed down. When a step forward takes 20-30+ years, then progress is slow.
By the 1990s there was enough discontent with the tokamak that the current “set” of private fusion companies started (e.g. TAE Technologies in 1998). Each company replicates the public fusion program, but most choose a different design to concentrate on, one that seems promising at the time of the creation of each company. As these designs are promising to deliver at a smaller size, progress is correspondingly faster and cheaper.
As an aside, this discontent with the tokamak is also evident within the public fusion program; Germany has invested heavily on the stellarator design (e.g. $1+ billion stellarator completed in 2015) and the UK has announced, in 2019, a large investment (£200+ million into the STEP project) to look into the spherical tokamak. The roadmap for the UK project has a duration that is significantly shorter than the ITER timeline, in line with private fusion companies. Note that both the UK and Germany are also participating in the ITER project.
In short, both the public fusion program and private fusion companies are following the same approach: they choose a design and they concentrate on making that design work. Fusion Reactors is following a different approach, but more on that in subsequent posts.
In the meantime, please continue spreading the word about Fusion Reactors.