(1) We welcome the openness of the ICRPfs approach regarding its draft report of 2005 recommendation.
(2) We welcome the intention of ICRP to simplify existing recommendations like compiling 11 Reports and 30 numerical values into one report and 4 numerical values. However, we feel that there are some misunderstandings or confusion for readers regarding dose constraints concept. We, regulatory authorities, have accountability to our nations and stakeholders when we introduce new concepts to regulation. Therefore, in order to introduce its new concepts in each country smoothly, more explanatory texts are required to be prepared by ICRP members or other appropriate experts.
(3) In particular, the relation between the individual-related protection/dose limits and the source-related protection/dose constraints are not clear and need further elaboration. In a situation without clear explanation about their relation, if regulatory authorities adopt the level less than the dose limit 1mSv/y as the dose constraint, the situation will be the same as with decease of the dose limit. By introducing the dose constraint, arguments based on misunderstanding might occur among nations or stakeholders that the standard of radiation became severe.
In addition, it seems that the concept of gdose constraintsh in draft report has broadened its meaning in comparison to the same term in ICRP Pub.60 and IAEA Basic Safety Standards. For example, current gdose constrainth is considered as one of the target dose of self-management by operators and it is very far from forced definition by regulatory authorities. Therefore, gdose constrainth level is usually under gdose limith level which are defined by regulatory authorities. However in draft report, gdose constrainth has similar meaning of gdose limith. This kind of change in the meaning of term causes a substantial confusion among regulatory authorities. If ICRP insists on this new concept, it is better to search for another suitable new term rather than using gdose constraintsh.
(4)Disappearance of gINTERVENTIONh
Although it is mentioned that the new ICRP draft report adheres fundamentally to ICRP Pub.60, the concept of gINTERVENTIONh has been disappeared.
As of now, there exist three grades of radiation control methods which are regulation, intervention, and not to control.
If we abandon the concept of intervention along with new ICRP draft report in the future, we can only take two choices (to regulate strictly by authority or let it be free) for every practice.
We have to review current interventional control policy (such as NORM, cosmic radiation for aircrews and passengers, etc.) and categorize into two choices.
It is obvious that this kind of impracticable conceptual change is not acceptable and causes confusion among not only regulatory authorities but also operators, workers, and public.
Comments on section 3.3.2: Radiological protection quantities: Averaging of dose
In section 3.3.2, paragraph 48, LNT hypothesis is used for estimating low dose stochastic effects. However, LNT hypothesis has been established in order to estimate the target dose of radiation control in low energy level with standing on the safer side for the purpose of risk management. There are no universal agreement for using LNT hypothesis to estimate health effects and no evidence of health effects induced by low doses of radiation. Therefore, it should be rewritten without LNT hypothesis or with the following sentences at the end of this paragraph.
gHowever, LNT hypothesis has been established only to estimate the target dose of radiation control in low energy level with standing on the safer side for the purpose of risk management. Therefore, it is necessary to acknowledge the limitation of LNT hypothesis and to be more careful to understand the meanings of above mentioned assumption, especially for regulators.h
Comments on section 5.2: The principles of radiation protection
In section 5.2, paragraph 133 and 135, the principles of protection, the definition of ea single sourcef should be clarified. What is ea single sourcef is not clarified. The application of the dose constraints to both a single source and several sources is mentioned in 5.2. For example, in Figure 2, it is difficult to clearly understand how ea single sourcef is applied in nuclear power plant, which possess several sources such as nuclear power reactor core, fuel assemblies outside reactor and radioactive wastes.
Comments on section 6.4: Radon in dwellings and workplace
In section 6.4, paragraph 179 and 180, radon in dwellings and workplace, we recommend that the approach given in ICRP Pub.65 should be continued. It may not be desirable to establish a dose constraint for radon in dwellings, especially for the public.
Dose control for workers has been strictly performed based on the dose limits, while action level for intervention against exposure of the public to existing sources such as radon should be depend on the situation related to controllability. It might not be acceptable to the general public that the dose constraints for existing exposure of the public is categorized in same level, 20mSv/y, as dose limit for radiation worker without any explanation of difference of principles for the two different approaches, gpracticeh and ginterventionh. It is also difficult to understand without any explanation that dose constraints for the existing exposure of the public,20mSv/y, is set to be quit higher than the dose limit , 1mSv/y, due to gpracticeh.
Comments on section 8.2: Natural radioactive substances in environmental materials
In section 8.2, paragraph 210 and Table 10, two kinds of exclusion level of NORM are mentioned. Although, the draft report does not mention any other NORM like Sm-147 or Re-187, most of the readers might think about 1 Bq/g for the rest of NORM because the draft report quotes RS-G1.7 (former DS161). On the bases of this report, following five elements such as K, Sm, Re, Rb, and Lu and their simple compounds are supposed to be considered as radioactive materials automatically due to its abundance ratio of NORM and its half-life. According to our calculation, activities of their pure metal status are 30.33Bq/g for K, 127.39Bq/g for Sm, 1019.05Bq/g for Re, 891.77Bq/g for Rb, and 48.72Bq/g for Lu. We also calculated some of their simple compounds like 21.14Bq/g for KOH, 18.21Bq/g for KCN, 15.90Bq/g for KCl, 660.05Bq/g for Rb2CO3, 43.04Bq/g for SmCo5, etc. These compounds are broadly used for industrial and daily use in the world without any attention to their radioactivities. It is usual to consider intervention level for these kinds of materials. However, there is no mentioning of intervention, and if the regulatory authority is requested to go strictly by their nations, it might cause big confusion regarding these material.
It is for this reason that RS-G1.7 mentions ggraded approachh regarding this matter to allow some range between IAEA exclusion level and actual regulation level for each country. We think, it will be better to add concept of intervention and graded approach or similar concept in this paragraph.
Comments on section 11: Protection of the environment
In section 11, paragraph 241 and Annex B, Protection of the environment, we recognize that the concrete framework for the protection of the environment is supposed to be discussed in new ICRP Committee 5 next year. Therefore, it is premature to describe environmental protection in detail as in the Annex B at this moment.