Recent Progresses in Concretes for Nuclear Waste
and Uranium Waste Containment
by Joseph Davidovits
published in Concrete International, Vol.16 (12), pp. 53-58 (1994)
The main objective in the management of nuclear and uranium radioactive wastes is to protect current and future generations from unacceptable exposure to radiation from man-made materials. This task can best be achieved by the use of one or more geopolymeric containment barriers to surround and isolate the wastes. The barriers fulfil two roles: they shield people from the radiation emitted by wastes, and they prevent or retard their movement, ensuring that they do not reach people in unacceptable concentrations. The main requirement is then to ensure that wastes remain isolated from people for the necessary length of time. This will vary, depending on the type of waste. There is an important distinction between nuclear wastes (high-level, medium-level and low-level), which eventually become harmless, albeit in some cases after a very long time, and uranium wastes which comprises radioactive wastes and chemically toxic wastes, and therefore will retain their toxicity for ever. The engineered geopolymeric structures of the repository are designed to stay intact for several centuries. After several thousands years, ground water will gradually penetrate the repositories and cause corrosion of the concrete structures. At this time, the radioactivity of the wastes will have fallen to a small fraction of its initial value, but chemical waste will remain toxic and harmful for the environment.
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