|Comments of the NSC secretariat of Japan on the draft ICRP recommendations
The secretariat of the Nuclear Safety Commission (NSC) of Japan appreciates ICRPfs continued efforts to improve the recommendations and thanks the ICRP for providing us with this opportunity to submit comments on its draft recommendations.
From the view point of being in charge of Japanfs nuclear safety policy, however, it questions whether the proposed new concept of radiological protection system is an improvement from the 1990 recommendations. It seems that the draft recommendations intend to introduce drastic changes in its concept without social requirement or clear rationale.
It is important that any revision of the ICRP 1990 recommendations should keep the basic concept as it has been employed in the regulatory systems of many countries. In Japan, the current national regulatory system has been constructed referring to the ICRP 1990 recommendations and related documents, taking the IAEA basic safety standards (BSS) into account. In order to avoid the confusion, it is important that the basic concept of the new recommendations should be the same unless new scientific data and information require a change.
The secretariat of NSC shares the questions and concerns expressed in the comments on the draft ICRP 2005 recommendations prepared by the IAEA secretariat and during the discussions in the meetings of the CRPPH Expert Group on the Implications of ICRP Recommendation (EGIR) of OECD/NEA.
The secretariat of NSC believes, for the reason stated above, that the new recommendations should be redesigned based on the 1990 recommendations rather than finalizing of the proposed draft recommendations with minor modifications. However, for the further clarification of the concerns of the NSC secretariat, the comments on some specific points of the proposed draft recommendations are provided below.
Justification has been considered as the first fundamental principle of radiation protection. It is desired that no substantial change should be made in the concept of ejustificationf from the 1990 recommendations.
2. Concept of dose constraints
In the draft recommendations, dose constraint is defined substantially different from the one described in the 1990 recommendations. In the 1990 recommendations, it is determined as a result of optimization of practice and, therefore, it is not regarded to be mandatory. This principle has to be maintained.
3. Maximum dose constraints and dose constraints
The ICRP draft recommendations adopt a new structure of gmaximum dose constraintsh and gdose constraintsh which is to be determined by the national authorities at the level lower than the gmaximum dose constraintsh. This twofold structure should be avoided as it will cause confusion in the current regulatory systems of each country.
4. Dose limits and dose constraints
The application of dose limits to workers is more practical than that of dose constraints when the individual dose is controllable by a dosimeter. In doing maintenance and/or renovation work at nuclear facilities, for example, dose rates in actual working places are changeable depending on the phase and situation of the work. In such a case, it is extremely difficult to apply dose constraints for the radiological protection of workers. Dose limits are more suitable for this purpose.
In order to avoid confusion, the exclusion should be defined as consistent with the IAEA Safety Standards given in RS-G-1.7 (DS161).
6. Protection of the environment
While it will take time before a concrete framework be proposed for the protection of non-human species, it is desired that due consideration should be paid to the design of a well-balanced and feasible framework.