There appear to be both generic-technological and national-institutional reasons which make radwaste management and disposal such an intriguing problem of public policy. These are related, but analytically separable. In this section we will concentrate on generic uncertainties related to radwaste disposal. Some authors have argued that disposal is not the appropriate goal for radwaste-management policy because the remaining technical uncertainties are too great and because the experience of waste management in the past has frequently been unsatisfactory. 1 Whatever the merits of this argument, radwaste policies in the UK, West Germany and Sweden all take disposal as their ultimate objective. I will therefore limit the discussion here to describing a conceptualization of this objective.
Furthermore, for the purpose of illustration, I will mainly use examples of solid-waste disposals to land. This is justified by the currently planned primacy of the land-burial option in national programmes compared with fluid discharges to the environment or solid-waste disposals to the sea. 2
The question of time has come to stand at the centre of all theoretical discussions of radwaste management because, unlike other toxic materials, time is a significant variable in the problem of management. Radioactivity decays through time, steadily reducing the difficulties of handling wastes and the risks associated with disposing of them to the environment. However, this relationship of activity with time is not a simple one. Radioactive materials are invariably composed of a number of different radioactive isotopes (radionuclides), each with a specific rate of decay. The principal radionuclides present in pressurized-water-reactor spent fuel are shown in Table 2.1, and their decay is graphically represented in Figure 2.1.