Does fusion involve radioactive waste?

A fusion power plant produces radioactive waste because the high-energy neutrons produced by fusion activate the walls of the plasma vessel. The intensity and duration of this activation depend on the material impinged on by the neutrons. Special low-activation materials, therefore, were and are being developed for fusion.

The activity of the waste quickly declines: after about 100 years to a ten-thousandth of the initial value. After a decay time of one to five hundred years the radiotoxic content of the waste is comparable to the hazard potential of the total ash from a coal plant, which always contains natural radioactive substances.

Careful choice of material obviates the need for permanent storage. After a lapse of 50 years 30 to 40 per cent of the total mass of the waste can be released without restriction. The remaining waste can be recycled after another 50 years and re-used in new power plants.