Abstract
The present publication deals with the radiological protection of members of the public following the disposal of long-lived solid radioactive waste using the ‘concentrate and retain’ strategy. It covers options including shallow land burial and deep geological disposal. The recommendations made in this report apply to new disposal facilities.
The main protection issue concerns exposure that may or may not occur in the far future, i.e. a situation of potential exposure. Constrained optimisation is the central approach to evaluating the radiological acceptability of a waste disposal system. In this context optimisation of protection is a judgmental process with social and economic factors being taken into account and should be conducted in a structured essentially qualitative way.
Two broad categories of exposure situations have to be considered: natural processes and human intrusion. Application of the radiological protection criteria to these two categories of exposure situations is different.
In the first case, assessed doses or risks arising from natural processes should be compared with a constraint of no more than about 0.3 mSv per year or its risk equivalent of around 10−5 per year. With regard to human intrusion, understood here as inadvertent human intrusion, the consequences from one or more plausible stylised scenarios should be considered in order to evaluate the resilience of the repository to such events. The Commission considers that in circumstances where human intrusion could lead to doses to those living around the site sufficiently high that intervention on current criteria would almost always be justified, reasonable efforts should be made at the repository development stage to reduce the probability of human intrusion or to limit its consequences. In this respect, the Commission has previously advised that an existing annual dose of around 100 mSv per year may be used as a generic reference level above which intervention should be considered almost always justifiable. Similar considerations apply in situations where the thresholds for deterministic effects in relevant organs are exceeded.
The conclusion of the report is that in the Commission's view, provided reasonable measures have been taken both to satisfy the constraint for natural processes and to reduce the probability or the consequences of inadvertent human intrusion, and technical and managerial principles have been followed, then radiological protection requirements can be considered to have been complied with.