If you look on YouTube you will see a lot of recent hype on the progress in controlled nuclear fusion reactors. Without seeing progress I guess the funding would soon dry up, call me cynical. The first nuclear fusion experiment I am aware of was the THETA experiment at Harwell that was started in 1954. Are we now suddenly, just 70 years on, seeing some real progress?
The ZETA fusion experiment ran at Harwell from 1954 to 1968. I worked at Harwell and Culham from 1973 to 1975, and fusion was still just 20 years away back then. Now, 70 years on from ZETA we are still (apparently) 20 years away from controlled nuclear fusion – do you see a pattern yet? With 50 years in semiconductor physics I learnt something very interesting – not everything is amenable to scaling. For example, it is not a good idea to keep reducing the size of a pressure sensor if you want a “good” pressure sensor. In electromagnetism the “goodness” of an electric circuit increases the smaller you make it – BUT – the “goodness” of a magnetic circuit increases with size (see Laithwaite). The only fusion reactors we see around us are the stars. Stars are pretty big. I suspect the “goodness” of a controlled nuclear fusion reactor also increases with size. If this is the case, then making tiny fusion reactors, just the size of a building, is a pointless task. The “goodness” factor is so crippled you will be lucky if you can even break-even. I strongly suspect that a fusion reactor, the size of a huge building, capable of supplying net power to the National Grid is not possible. Come back to this post at the end of the next 20 years to see how we get on (but I won’t be here to say I told you so).
