Fusion

Fusion Controlled

Controlled nuclear fission have been carried out before fission bombs were built. Soon after the detonation of atomic bombs, fission reactors have been designed, built, and applied to generate power.

In contrast, the first fusion bomb exploded Enewetak atoll on Nov. 1, 1952, but controlled fusion for power generation has not been realized yet.

In parallel with the development of the hydrogen bomb, massive efforts towards achieving controlled thermonuclear fusion (CTF) were initiated in a number of countries. The most promising reaction is

D + T ® 4He + n + 17.6 MeV. This reaction releases a large amount of energy, and has the lowest ignition temperature, 40,000,000 K.

Basic requirements for CTF of the above reaction are to:

  1. achieve a temperature of 100,000,000 K,
  2. confine a large number of nuclei in the plasma in a small volume for a length of time,
  3. sustain the fusion
  4. extract energy from the products after fusion.
To date, it is still a challenge to produce more energy than the energy used to heat the plasma and maintain a steady fusion rate.

Magnetic confinement and inertia confinement are well known techniques to maintain a large number of nuclei in a small volume for a long period of time.

© cchieh@uwaterloo.ca