POINT OF VUE: The Dangers of Fusion

WISE-Paris, London, November 2003
By Dr I. Fairlie*

[Posted 28/11/2003]

If nuclear fusion were ever developed commercially, radioactive discharges would increase considerably, since the core of each commercial fusion reactor would contain about 4 x 1018 Bq (~100 million curies) of radioactive tritium as estimated by Coyle and Ikrent [Coyle 1978, Ikrent 1976]. The number of becquerels is 4 with 18 zeroes after it: it is an extremely large amount of tritium. Even if only 0.01% of this inventory were lost each year, this would amount to 400 TBq (terabecquerel or million million Bq) of tritium per annum, ie more than the amount currently released to air annually from all of the UK's nuclear reactors or total releases from all of the 34 French 900 MW reactors combined. This estimate is similar to Feinendegen's estimate (1980) that 110 TBq of tritium would be released per year into the environment in the form of "routine" discharges, for every 1,000 MW of future fusion capacity (or more than 10 times the average amount released by a French 900 MW reactor).

In addition to the hazard of radioactive tritium is the lithium in fusion reactors. Should there be an explosion (recall the vast amounts of energy which would be constrained in these reactors), the consequent fire would result in the lithium catching fire. Lithium is exceedingly flammable and burns with great intensity, so it can be expected that a substantial fraction of the reactor inventory of tritium would be released. This would have a truly catastrophic effect on the area downwind from any fusion reactor. Luykx [Luykx 1986] and Coyle have estimated that these "accidental" releases could add a further 3.7 x 10 18 Bq of tritium being discharged per year on average if a large number of reactors were built. These estimates are by authoritative fusion scientists and they are worryingly high, but there has apparently been no refutation of these estimates in the scientific media.

Although these references are from the 1970s and 1980s, their age is immaterial. They indicate that, during previous pushes for fusion power in those decades, a number of scientists were so concerned about the dangers of fusion they put their careers on the line to say so. With the latest calls for fusion, we should recall their concerns and objections, and indeed their courage.


*Ian Fairlie is an independent consultant specialising in radiation biology. The UK government has appointed him Scientific Secretary of CERRIE (Committee for the Evaluation of Radiation Risks of Internal Emitters). Here he expresses his personal opinion.


  1. Coyle, P., "Laser Fusion: Status, Future and Tritium Control" in “Behaviour of Tritium in the Environment”, Proceedings of a Symposium in San Francisco , IAEA and NEA (OECD), October 1978
  2. EDF 2003, http://nucleaire.edf.fr/English/informer/chiffres/fs_chif01.html
  3. Ikrent, D. et al., "On the Safety of Tokamak-type, Central Station Fusion Power Reactors", Nuclear Engineering Design, vol 39, p. 215, 1976
  4. Feinendegen, L. et al., "Radiation Problems in Fusion Energy Production", Radiat. Environ. Biophys. vol 18, pp. 157 to 183. 1980
  5. Luykx, F. and Fraser, G., "Tritium Releases from Nuclear Power Plants and Nuclear Fuel Reprocessing Plants" Radiat Prot. Dos vol 16 (1-2), pp. 31-36. 1986