|Comments from the NEA (submission 1 of 5)
Expert Group on the Implications of ICRP Recommendations
For a System of Radiological Protection (EGIR)
Discussions between the NEA’s Committee on Radiation Protection and Public Health (CRPPH) and the International Commission on Radiological Protection (ICRP) have for several years focused on providing regulatory and other end-user feedback on the Commission’s draft texts, and on the broad principles on which the Commission’s new recommendations will be developed. With the issuance of the ICRP’s draft recommendations for comment, following their initial presentation at the IRPA-11 Congress in Madrid in May 2004, the CRPPH agreed to provide broad-based and constructive comments on this draft to the ICRP.
Commenting on the draft recommendations has been co-ordinated, within the NEA, through the collection of input from all relevant NEA Standing Technical Committees, including the Committee on Nuclear Regulatory Activities (CRNA), the Committee on the Safety of Nuclear Installations (CSNI), the Radioactive Waste Management Committee (RWMC), the Nuclear Development Committee (NDC), the Nuclear Science Committee (NSC) and of course the CRPPH.
It should also be noted that, following the 2nd Asian Regional Workshop on the Evolution of the System of Radiological Protection, held in Tokyo in July 2004, an ad-hoc Japanese EGIR sub-group was formed to more directly collect views from Japanese radiological protection authorities and advisory bodies, relevant radiological protection research organisations, and industry.
Taking all these comments into account, the EGIR analysed the ICRP draft recommendations, focusing on how their wording could be improved to better clarify the Commission’s intended meaning, and to help the text to better address the needs of policy makers, regulatory authorities and radiological protection practitioners. Both general comments, as possible tied to specific chapters or sections, and specific suggestions for textual changes have been developed. These are each supported by explanations and rationale for the comment or proposed change.
The EGIR focused its efforts on the development of specific suggestions with respect to the text of the recommendations. However, some more general comments and reoccurring themes emerged during discussions. As best possible, these are tied to specific sections of the document.
ICRP and Document Development Processes
• The process that the ICRP followed in developing its new draft recommendations is seen to be excellent. This has included the initial publication of Roger Clarke’s paper on Controllable Dose, various meetings and conferences to discuss ideas and dialogue on solutions (e.g. the two NEA/ICRP conferences in Taormina and Lanzarote, the two IAEA conference on the Environment in Sydney and Stockholm, the two NEA Asian Regional meetings in Tokyo, meetings with the NCRP in Washington DC, the IRPA-11 Congress in Madrid, etc.), and finally placing the draft on the web and requesting comments. The EGIR agreed that this process had allowed the ICRP to collect valuable feedback on its ideas, and had afforded the RP community the opportunity to dialogue with the ICRP and foster mutual understanding.
• There is strong consensus that ICRP recommendations should in all countries form a basis for coherent radiological protection policy, regulation and application. As such, there is agreement that the new recommendations must represent good science, as well as applicable and coherent principles that can be universally applied.
• In order to assure that specific terms are used consistently in this document and in other ICRP publications, it is suggested that a Glossary of Terms should be developed, either as an Annex to the Commission’s main recommendations, or as a stand-alone document. This could include such terms as “Single Source”, “Practice”, “Dose Constraint”, etc.
• Section 1.2 of the recommendations presents the Commission’s motivation for change and briefly summarises the most significant features. It would be quite helpful if the Commission would also express its views on the benefits of changing to this “new” approach. This could be tied into the rationale for change that is presented in paragraphs 5 through 9. The idea of presenting the Commission’s main changes and rationale for change in a foreword, perhaps even replacing the Executive Summary, could also be considered.
• Similarly, there has been much concern with regard to the cost of change associated with the updating of national regulations and international standards. The Commission has stated on several occasions that it does not see the need for immediate change as a result of its new recommendations, and might mention, in the early part of the document, that such updating could be accomplished through the normal cycle and timeframe of regulatory review and modification, i.e. that the changes resulting from the new ICRP recommendations can be incorporated in future revisions of standards.
• There are several places in the draft recommendation that express the Commissions “intent” to develop recommendations, rather than expressing specific recommendations. The text on the identification of exposed individuals (section 6.3.1), and on the protection of the environment (section 11) are particular examples of this approach. In places, the document almost appears to be a “work in progress”. The Commission should take the time that is necessary to develop clear recommendations in all these areas, and should then clearly express its views. The final version of RP05 can include reference to “building block” recommendations, such as the individual, or optimisation, but should be a polished, complete and self-standing document upon its completion.
• The use that the Commission now suggests for dose constraints, covering all sources and exposure situations, is a significant change from the use of dose constraints presented in Publication 60. The explanation of this in the current text does not addressed concerns that such a change could pose significant problems for its practical application, particularly for accident and existing situations. The Commission should more explicitly present its rationale for change, and its thoughts with regard to practical application.
• The new emphasis that the Commission puts on the importance of stakeholder involvement in Justification and Optimisation decision making is seen as a valuable and important element of the new recommendations. It is also seen as a clarification of roles and responsibilities as recommended by the ICRP, and as complementary to the Commission’s stated objective to simplify its system of radiological protection.
• The use of a matrix approach to describe the various elements and attributes of individual exposures distributed in space and time is seen as very useful for decision making (see section 7.2). As discussed in the detailed comments, this approach needs further clarification, but broadly provides for the development of dosimetric data at the level of detail and refinement most appropriate to support the decision being made. The didactic material presented by Prof. Clarke to the EGIR, showing possible approaches to weighting (e.g. as doses become small, and as doses are received at times increasingly in the future), was seen as particularly useful.
• The Commission is now recommending a new unit, RBE-weighted absorbed dose for Tissue Reactions, to be measured in J kg-1 and called the gray-equivalent (Gy-Eq) (see paragraph 94). This choice is seen to add clarity to the assessment and reporting of large doses to tissues or organs. It is hoped that, should further serious irradiations occur, such as those at Tokai-mura, the use of this new unit will facilitate the understanding and communication of the dosimetric situation, and will assist in defining appropriate medical treatments for victims.
Further Clarity Needed
• The Commission should be more specific, probably in Section 1, with respect to the role it expects its recommendations to play, particularly with respect to the roles played by international intergovernmental organisations such UNSCEAR, IAEA, EC, and NEA. The EGIR saw the role of the ICRP as developing radiological protection principles, based on the best scientific datea currently available, and on an understanding of relevant societal aspects, in order to support the development of policy and regulations, and approaches to practical application, at national and international levels.
• Paragraph 8 of the draft recommendations states the Commission’s desire that RP05 should “…consolidate all advice included in and developed since the 1990 recommendations…” In several other places in the document, however, RP05 suggests that the Commission remains in agreement with recommendations given in previous reports (e.g. paragraph 29 referring to documents 77, 81 and 82; paragraph 185 with reference to publication 60). The true status of recommendations from previous documents is thus unclear. The EGIR suggests that the final version of RP05 should be a stand-alone document. Any text from previous recommendations that is needed for this purpose (e.g. text from publication 60 explaining the choice of numerical dose limits, text from publications 77 or 81 explaining the Commission’s policy on radioactive waste) should be included in the final version of RP05.
It is also strongly suggested that the future status of publication 60, and all subsequent publications (e.g. no longer valid, superseded, still valid), should be clarified.
• The earlier publications mentioned above use various rationale in support of the numerical criteria they recommend. Maintaining reference to these numerical criteria and their rationale could thus pose a problem in terms of the Commission’s desired goal of simplification and consolidation around only a few numbers of more-or-less common rationale.
• In order to more appropriately balance RP05, much of the detailed information currently contained in the document (particularly in chapters 3 and 4) should be considered for an annex or a foundation document
• Justification and optimisation are presented as a judgemental balance of costs and benefits. However, the notion of benefits from exposure-causing activities is not sufficiently highlighted. The notion of benefits should be more visibly presented in the text on Justification and Optimisation (sections 2 and 5).
Specific Aspects to Clarify
In addition to the general comments made by the EGIR, several areas in need of additional clarification were identified. The Group did not necessarily propose specific alternative text for all of these areas, but rather tried to identify those aspects that were unclear so that the Commission could then make modifications along the lines of its particular vision.
• While the principle of Justification is retained by the Commission, it is given very little text in RP05. It is suggested that the fundamental nature of Justification be augmented in section 2.2, and that a specific section on Justification should be added to section 5.2 on the principles of protection.
• Paragraph 18 suggests that justification is the responsibility of the government. This is clearly not the case in medical exposures, which are discussed in paragraph 19. Paragraph 18 should state that it does not apply to medical exposures (see specific comments).
• Section 5.2 describes the concept of dose constraints. However, the definition now used by the Commission is different from that in Publication 60. This change needs to be explained with specific text, particularly how dose constraints for practices would be used in conjunction with dose limits.
• A key aspect of the Commission’s new definition of the concept of dose constraints is that these apply to single sources only. Because the definition of a single source can be difficult in practice, and because the Commission’s use of dose constraints is new with respect to Publication 60, some clear discussion of the practical aspects of identifying sources and choosing appropriate constraints is needed.
• In this same fashion, dose limits should be presented more clearly throughout the text as applying to an individual’s total dose from multiple sources, and their relationship to dose constraints, ALARA and the optimisation process should be explicitly discussed.
• Dose constraints are presented as an upper bound for optimisation, however, it is not clear from the text, either in sections 5.2 or 7 (on optimisation) how dose constraints can be practically used. This is particularly true in accident and existing situations where the relationship between dose constraints and what used to be called intervention levels is not at all clear.
• The Commission now focuses on three types of exposure situations: normal, accident and existing. These are briefly presented in section 2.2. However, very little text in section 5.2 is devoted to explaining how dose constraints would be used with optimisation in these three situations. The application of dose constraints in these situations will be key to the implementation of these new recommendations, and should thus be much more clearly explained.
• In order to clarify its recommendations, the Commission has decided not to retain the “intervention” as a class of situation. Although this choice is given mixed reviews, it is agreed that the Commission has not sufficiently explained how dose constraints can be applied in what were called intervention situations, and are now called emergency and existing situations. More specifically, Intervention Levels were levels below which no action was generally needed, while dose constraints require optimisation below. The articulation of the old and the new needs to be much more clear. Additionally, the group agreed that the concept of averted dose has been found to be very valuable for decision making. It will be appreciated, therefore, if the Commission gives a detailed explanation how this concept fits into the present concept.
• The three exposure situations (normal, accident and existing) that the Commission is now using are highly relevant to the application of its recommendations. These are, however, little described in the text of RP05 (as mentioned above under dose constraints), and merit clear explanations that would assist in the application of the Commission’s principles. Such text would be useful in section 5. Some points of confusion need to be cleared up:
• Normal seems to be the same as Practice. The use of these two terms should be clearly explicit throughout the text. For example, paragraph 185 describes both “doses in normal situations”, and “exposures from sources related to practices”, thus somewhat confusing these terms.
• The concepts of Normal Situations and Existing Situations CAN be seen to overlap in their PLAIN ENGLISH usage, for example, radon exposure is natural and thus can be viewed as the normal situation.
• The Commission’s choice to no longer distinguish practices from interventions has caused a significant amount of confusion. It is not clear from the RP05 text what will happen to national regulations and international standards for Intervention Levels, or whether the new application of dose constraints to accident situations will affect the current level of international consensus on numerical values. However, the EGIR found Prof. Clarke’s discussion of regulatory intervention levels being the result of optimisation below a dose constraint to be valuable, and recommends that the explanation of these issues in the RP05 text better reflect his argumentation.
Exclusion and Authorisation
• In view of the international consensus that has been built in the development of IAEA Safety Guide RS-G-1.7, the EGIR felt that the Commission should reflect the text, with its caveats and nuances, and numerical values of that Safety Guide in its recommendations. This would mostly apply to sections 2.3 and 8.
• In addition, the EGIR noted that decisions relating to exclusion and authorisation will in general reflect many aspects beyond dose considerations, for example, the nature of the activity or source, and the total activity being exempted. This should be reflected in the document, particularly in paragraphs 25 – 26.
• The values for exclusion that the Commission recommends in table 10 seem to be too high to apply to building materials, as such these would seem to be qualified exclusion levels (i.e. not applying to released materials used in building). The Commission should thus reconsider these values to assure that its use of the term exclusion is, indeed, in the unrestricted sense (see comments on paragraphs 209, 210 and table 10).
• The EGIR noted that the process of regulatory authorisation has been elaborated by another of the CRPPH expert groups, and that the report on this will be published in early 2005. In particular, the decision-making process has been schematically diagrammed, with each decision and process described. It is suggested that the Commission could reference this work (or perhaps even include the flow-diagram – see Annex 1 to this report - in its recommendations) to facilitate the regulatory application of its recommendations.
Natural Background and Risk
• Some members of EGIR felt that the use of natural background doses as a relative benchmark for numerical restrictions (dose constraints, dose limits) is appropriate, whereas others favoured to retain the traditional risk-based approach. However, the Group felt that the role of natural background in the selection of numerical values for dose constraints and limits poses difficulties. Additional rationale for these numerical selections, beyond comparison to natural background, is needed.
• The concept of risk from radiation exposure is useful for relative comparisons with other risks, particularly in the future as radiation and other risks become understood with increasing accuracy. This should be stated somewhere in the recommendation.
• There is great uncertainty in our understanding of radiological risks. As such, risk coefficients should not be expressed with an unrealistic level of precision or certainty (i.e. paragraph 111, 6.2 10-2 Sv-1).
Other Areas Needing Clarification
• Chapter 11 on the protection of the environment should be greatly reduced. Its focus should be on Policy aspects, and on recommendations as to what to do until science better supports policy decisions.
• The EGIR felt that Appendix B is far too detailed for the needs of this recommendation, and should be deleted.
Consistency of Terminology
• The text is in need of editorial polishing, particularly in the consistent use of terminology. The use of exposures in Normal Situations, and exposures from Practice have already been cited. Another frequently used concept is that of the “National Regulatory Authority”. Several different formulations are used in the text, which should be avoided in the final text.
• The EGIR felt that replacing the term “Deterministic” with the term “Tissue Reactions” (paragraph 40) was not a good choice. While understanding that the word deterministic is used differently by different disciplines, nuclear safety for example, the Group felt that the use of deterministic in an RP context is well understood within the profession. Further, it is not clear that, medically, cancer is not a tissue reaction, thus rendering the term somewhat ambiguous. The Commission is encouraged to review this change and, if deterministic can not be kept, to propose a third option.