Comments by the German Commission on Radiological Protection (SSK):
The German Commission on Radiological Protection (SSK) appreciates that the key protection concepts and principles of ICRP Publication 103 (ICRP 2007) are consistently applied to geological disposal in the current draft "Draft Radiological Protection in Geological Disposal of Long-Lived Solid Radioactive Waste" (ICRP 2011). Disposal facility life phases (pre-operational phase, operational phase and post-operational phase) and relevant timeframes for radiological protection (time of direct oversight, time of indirect oversight and time of no oversight) are defined. The principles justification, optimization and application of dose limits are implemented in the draft, also the definitions of basic exposure situations (planned, existing and emergency situations). By this means a uniform radiation protection for the final disposal is achieved.
The SSK also explicitly appreciates the requirement, that waste treatment and waste disposal must already be an integral part of the licensing process for practices in which radioactive wastes are generated .
From the perspective of the SSK the following additions and modifications are desirable:
It should be specified explicitly, how in the situation of a human intrusion the radiation exposure for intruders is to be evaluated. (Present draft seems to imply that they should not be considered.)
It should be expressed that the protection should not only be guaranteed as long as possible from the point of view of the waste-producing generation (while maintaining the reasonability), but also as long as necessary from the perspective of future generations.
(26)-(30) and Figure 1:
Figure 1 of the draft shows only the ideal course of establishment, operation and closure of a repository as well as the post-closure phase. It would be helpful to implement procedures that can be applied when negative decisions have to be drawn at a late stage (decision to stop the disposal, decision to take waste out etc. at different stages between siting decision and the end of the phase with indirect oversight).
The safety case also includes in particular the relevant evidence (and not just a statement of principles and strategies). This should be supplemented.
It is unclear what an "indirect option" is. It would be helpful if this were explained.
For the comparison of the level of protection for the distant future with the present protection level, it is necessary that the exposure estimates for the distant future represent the potential future exposures to a sufficient degree according to current knowledge. This should be expressed in the ICRP publication.
(48) and Table 1:
The actually foreseeable developments have to be considered in the design of a repository. For these developments, the health risks caused by additional radiation exposure in the distant future should be limited to the level that is currently accepted. This should be expressed in the ICRP publication.
To limit the consequences of the developments that have to be considered in the design of a disposal, not only the risk but also the maximum effective individual dose should be limited for each of these developments.
This dose value, which is not weighted by a probability and limits the impact of each development that is considered in the design, should be consistent with the today´s limit for design basis accidents. The value should be related to the lifetime dose for continuous exposure. The value then lies in the range of the fluctuation of regional natural background radiation.
(48) and Annex 1, line 1528:
The risk limitation refers to the integral risk caused by all developments that have to be considered in the design of a repository. This should be clarified in the ICRP publication.
(48) and Annex 2 (particularly line 1730):
The risk contribution of an incident for which a probability of occurrence per year can be specified, results from the likelihood that in the distant future a person receives in a year an incident-related increased radiation exposure, and the health risk from this exposure. It should be noted that the probability of the exposure of the person is not equivalent to the probability of the occurrence of the triggering incidence in a year, but (simplified) to the product of the probability of the incident in a year and the duration of the consequences of this incident (i. e. the release of radionuclides into the biosphere). This should be clarified in the ICRP publication.
Further instructions for linking radiological risks and probability of occurrence of exposure situations and exposures should be given, particularly with regard to the implementation in practice. This is necessary to minimize differences in the application of the recommendations between different authorities.
(52) and Table 1:
Even in the case of a non-design basis evolution in the distant future no situation should occur that would be a radiological emergency situation according to today's standards and that would make radiological protection measures necessary.
It would be useful if criteria were given for the decision whether a possible development should be considered in the design of a repository or not (or in other words, according to what criteria the development line "design-basis evolution" or "Non-design basis evolution" is assigned in Table 1). In the text only such non-design basis evolutions are mentioned, which are caused by severe natural destructive incidents. This suggests that all non-excluded developments that are not triggered by such incidents should be considered in the design of a repository.
For the non-design basis evolutions, the “application” of reference values is recommended. Since the application should be made in the planning phase (in the context of site selection and design of the repository), this would mean that the selected option (site, design) should satisfy those values. The reference values then represent a kind of restriction, although possibly are less binding. It would be helpful if the term "application" would be clarified in this context.
(58) and Table 1:
The consequences for the general public of inadvertent complete intrusion into a repository should be evaluated with the same radiological scale as other non-design basis evolutions. Therefore the inadvertent complete intrusion in the distant future should not lead to a situation that would be by today's standards a radiological emergency situation and that would make radiological protection measures necessary.
(83) and Annex 2:
A statement should be made by the ICRP to clarify which lifetime risks are considered acceptable and how these lifetime risks are to be determined. For this purpose, certain conditions should be recommended for use, for example, the maximum age of the persons under consideration. This is also necessary to minimize differences in the future application of the recommendations.
ICRP 2007 International Commission on Radiological Protection (ICRP): The 2007 Recommendations of the International Commission on Radiological Protection. ICRP Publication 103. Ann. ICRP 37 (2–4).
ICRP 2011 International Commission on Radiological Protection (ICRP): Radiological Protection in Geological Disposal of Long-Lived Solid Radioactive Waste. Draft report for consultation, ICRP ref 4838-8963-9177. July 21, 2011