Hazard potentials of radioactive waste. Consequences of the development of ICRP directives upon evaluation

The hazard potential is defined as the potential applicable effective dose relative to the benefit produced, i.e. electric power. As a yardstick for comparing human intervention into natural developments, unirradiated reactor fuel is much more suitable than natural uranium deposits, for it allows a direct comparison to be made of the consequences of using nuclear power. Under these boundary conditions, it becomes apparent that the direct disposal of PWR U fuel and HTR U fuel will meet the reference level not in technically foreseeable periods of time, but rather after millions of years. This is true irrespective of the highly different burnups of the nuclear fuels considered. Also reprocessing as it is now being conducted is unable to achieve the goal of a technically manageable storage period, as it reduces the storage period required only to approximately 100,000 years. What is necessary, instead, is a much finer separation of Pu, including Np, Am, and Cm, to achieve the reference level with reprocessing waste within, e.g., 2000 years. Recycling in a PWR the Pu separated as U-Pu MOX fuel has only a marginal effect on the development of the hazard potential. Compared with the HTR cycle, a clearly greater hazard potential is observed at comparable burnups. If a clearly closer approximation to the goal is to be achieved in this case, breeding new Pu in the Mox fuel must be avoided, for instance, by means of inert matrices and by using subcritical transmutation systems, respectively. (orig./HP)