Question: How long will it be until we can use nuclear power for energy?

Piers Barnes answered on 9 Jan 2017:

We already do use nuclear power in the UK, there are 7 nuclear plants in the UK which generate about a sixth of our electricity(https://en.wikipedia.org/wiki/Nuclear_power_in_the_United_Kingdom). These are all fission reactors which harvest the energy released when heavy nuclei are split.

The kind of nuclear power mentioned in the Christmas Lectures was nuclear fusion, which harvests the energy released when light nuclei are combined. The reaction requires deuterium as the fuel which is much more abundant than the fuels for fission, so if you exclude the considerable CO2 emission required to build the reactor, fusion should be much cleaner than burning fossil fuels. The waste products from fusion have a shorter radiation half-life and are in principle safer to dispose of. You still have a highly radioactive reactor to deal with at the end of the reactor life, with all the associated problems, though. The technology is still in the research phase for power generation, and is very technologically challenging because of the difficulty of managing the intensely hot plasma required for fusion to occur.

People have been saying the technology is “about 20 years” from commercialisation for at least the last 40 years, so it is hard to really know when all the problems will be solved, but I believe progress is being made…