|Comments on the Draft ICRP Recommendations
I appreciate the vigorous efforts of the International Commission on Radiological Protection (ICRP) and also express special gratitude for the openness and sincerity in revising the former draft Recommendations in response to public comments.
The new draft Recommendations are scientifically updated, introducing new scientific findings, as well as being stable and consistent with the former 1990 Recommendations. I highly appraise the new draft and hope my comments will contribute to make the excellent Recommendations even better.
#1. Major comments:
Paragraph 190 describes that gthe responsibility for judging the justification usually falls on government or government agencies.h However, the responsibility falls on the operators and the other stakeholders, as well as government and government agencies, because each of them is concerned in the social process for judging the justification from each of their standpoints, as Dr. Holm, the Chair of the ICRP, explained in the 3rd Asian Regional Conference on the evolution of the system of radiological protection, held in Tokyo, Japan in July, 2006. So this intention should be more clearly described in the Recommendations.
1-2. Dose constraints
It may cause confusion to introduce dose constraints into national legislation or regulation systems because dose constraints in the draft Recommendations may be interpreted in various ways.
For example, in emergency and existing exposure situations, the difference between dose constraints and action levels is not clearly written in the draft, such as in paragraphs 279 and 348.
Moreover, the description of dose constraints in planned situations differs from that in emergency and existing exposure situations. For example, the draft mentions that dose constraints gshould be viewed as a level of ambition and not as a mandatory level which must be achievedh in emergency and existing exposure situations in paragraph 223. On the other hand, it points out that gthe optimization process should reject any protection options that would involve doses above the appropriate constrainth in planned situations (paragraph 222). This can be interpreted as stating that dose constraints in planned situations should be regarded as ga mandatory levelh which must be achieved in law.
Therefore, the concept and definition of terms, including the dose constraints, need further clarification.
In addition, it should be clearly stated that the dose constraints remain one of the means to keep the exposed dose below the dose limits in planned situations, and other methods could also accomplish that purpose.
1-2-1: It is described in paragraphs 184 and 198 that a dose constraint is gthe most fundamental level of protection.h This should be changed as follows;
(Paragraph 184) gAnother usefulh level of protection, therefore, is the source-related restriction to the dose that individual may incur, namely the dose constraint.
(Paragraph 198) The level of protection gused in the optimization processh is the source-related restriction called a dose constraint or risk constraint for potential exposures.
Reason: This expression will cause misunderstanding that a dose constraint is more fundamental and important than a dose limit. My understanding is that the importance of a dose limit has not been changed in this draft.
1-2-2: Paragraphs 201 and 211 describe dose constraints as gto be fixed at the national or local level.h This should be changed as follows;
(Para. 201) It will usually be appropriate for dose constraints to be fixed gin each nation or regionh taking account of the Commissionfs guidance.
(Para. 211) It will usually be appropriate for such dose constraints to be fixed gin each nation or regionh.
Reason: This expression will cause misunderstanding that dose constraints can be fixed only by national or local governments. In my understanding, there could be cases where operators are involved in the setting of a dose constraint to some extent.
1-2-3: Paragraphs 218 and 219 describe that selection of a dose constraint is the responsibility of national authorities in emergency and existing exposure situations. This should be amended as follows;
(Paragraph 218) Selection of this level, now termed a constraint, is gusuallyh the responsibility of national authorities.
(Paragraph 219) It is gusuallyh the responsibility of national authorities to select this constraint.
Reason: This expression will cause misunderstanding that the responsibility for setting a dose constraint falls only on national authorities. In my understanding, there could be cases where operators are involved in the setting of a dose constraint to some extent.
1-3. Underlying concepts and rationales
It is desirable to mention the underlying rationales or concepts for the important values which the ICRP recommends. Some of the examples are dose limits of the occupational and public exposures in the planned situation, dose constraints of the waste materials (paragraph 217) and constraints of Radon (paragraph 301).
Reason: The General Recommendations are dependent and are read not only by experts but also various other people. Therefore, summarized rationales and concepts should be mentioned in the General Recommendations along with the citations to the related publications for detailed explanations.
#2. Minor comments:
2-1. LNT hypothesis
The word gscientifically reasonableh in paragraph 55 would be better replaced by greasonable and practicableh.
Also gscientificallyh in paragraph 57 would be better replaced by another word such as greasonablyh.
Reason: The LNT hypothesis is useful for the sake of Radiation Protection, but is still scientifically hypothetical. Using the word gscientificallyh may lead readers to misunderstand the hypothesis as scientifically established and to be inclined to inappropriately estimate risks for low-dose exposure to large populations using collective dose based on the hypothesis, as is mentioned in paragraphs 146, 147 and 229.
2-2. Cancer and hereditary/heritable effects (section 3.2)
The term gcancer and hereditary/heritable effectsh should be renamed to gcancer and other effects.h
Reason: It is best to avoid describing the cancer and hereditary/heritable effects on even ground, because the term gcancer and hereditary/heritable effectsh may cause excessive anxiety and fear of the hereditary/heritable effects.
I do not deny, from the viewpoint of radiation protection, the addition of the detriment-adjusted nominal risk coefficients for the hereditary/heritable effects to those for the total stochastic effects.
2-3. Facilities for processing naturally occurring radioactive materials
Paragraph 288, concerning industries involving exposures to naturally occurring radioactive materials, describes that gNew facilities for processing such materials, where radiological protection requirement can be considered during the design stage, are planned situations.h This should be replaced as follows;
(Paragraph 288) New facilities for processing such materials, where radiological protection requirements can be considered during the design stage, gshould desirably be treated as facilities inh planned situations.
Reason: It will be difficult for all new facilities to be treated as planned situations because making a clear distinction between new and existing facilities could be rather difficult and will cause inconsistency in regulations on these facilities.
2-4. Aircraft exposure
Some specific comments are required to aircraft exposure, based on the ICRP Publications 60 and 75.
Director for Radiation Protection Policy
Office of Radiation Regulation
Ministry of Education, Culture, Sports, Science and Technology (MEXT)