1. The environmental protection should be established by the methodology of environmental assessment before the construction of the facilities which has already been well-established in the other industries, on the basis of consideration of balance between human protection and environmental protection. In this respect, it is important to assess ionizing radiation and to optimize the radiation protection to minimize the impact on the environment in advance with the construction of nuclear facility that will be the radiation source. For the planned exposure situation, the environmental protection after the construction can be achieved by appropriately protecting the humans. For the emergency and existing exposure situations, on the other hand, the environmental protection can be achieved by an integral optimization of radiation protection for both humans and non-human species, not by the environmental viewpoint only.
2. Given the proposed concept of similarly expanding the radiation protection framework for human protection into that for environmental protection for emergency and existing exposure situations, it is still difficult to see how to practically implement it. It is required to further discuss this issue by considering the optimization of the radiation protection for humans and non-human species. The methodology of reducing the absorbed dose of non-human biota in emergency and existing exposure situations should be practically provided in developing the new category of environmental exposures.
622 In the paragraph (198) and Fig. 3 given in the ICRP 2007 Recommendations, the source-related restriction is defined as the reference level for emergency and existing exposure situations. The reference level can be applied for the individual residual dose in some cases, but the limited expression as total residual dose is not appropriate. In this context, the sentence should be modified as follows.
Emphasis on optimization using reference levels in emergency and existing exposure situations focuses attention on the residual level of dose remaining after implementation of protection strategies. This residual dose should be below the reference level, which is regarded as the source-related restriction or is sometimes regarded as the restriction of the residual level of dose (ICRP 103, 2007), that the regulator has planned not to exceed.
630 Regarding the Fig. 1 (Range of reference levels and dose constraints for human radiological protection), the framework for source-related dose constraints and reference levels should be provided in the format of table or sentences, which is consistent with the ICRP 2007 recommendations (Table 5). If the authors want to express the framework as the figure, the range of dose constraint set for public exposure in planned exposure situations should be at least modified as “1 mSv or less” in order to avoid the confusion about the minimum numerical value of the dose constraint.
684 With regard to the paragraph (38), the concept of ERL is unnecessary. Considering that the DCRL is given as the band of reference levels, optimization of radiation protection can be achieved by taking the efforts at a level below the relevant DCRL as the tool of optimization. Furthermore, in the paragraph (42), it is noted that the Commission recommends that the level of ambition for optimization would be to reduce exposures to levels that are within the DCRL band. In this context, the simple and overall radiation protection systems can be established by introducing the concept of DCRL for planned, existing and emergency exposure situations without introducing the concept of ERL. Therefore, the sentence of “The Commission therefore recommends that a value, termed the Environmental Reference Level (ERL), be established for a specific source at a level below the relevant DCRL for the relevant RAP or RAPs for use in the optimization of protection. This is illustrated in Fig. 3.” should be deleted.
735 Figure 4 should be deleted. Appropriate countermeasures are not given in the sentences for the case that the order of magnitude bands of dose rate exceeds the severe effects level.
761 Paragraph (43) should be deleted. Also, the word “similarly” in the paragraph (44) should be deleted. The concept of representative person means the representative of the more highly exposed individuals in the relevant population, and the representative person is set by considering the dose distribution. On the other hand, the representative organisms are just the example of reference animals and plants. The word “similarly” is inappropriate in this context.
For the purposes of protecting the environment, the Commission recommends the use of Representative Organisms to represent the actual objects of protection in the specific circumstance under consideration.
794 The concept of ERL is unnecessary as already noted in the comment for the paragraph (38). Considering that the DCRL is given as the band of reference levels, optimization of radiation protection can be achieved by taking the efforts at a level below the relevant DCRL as the tool of optimization. Furthermore, in the paragraph (42), it is noted that the Commission recommends that the level of ambition for optimization would be to reduce exposures to levels that are within the DCRL band. In this context, the simple and overall radiation protection systems can be established by introducing the concept of DCRL for planned, existing and emergency exposure situations without introducing the concept of ERL.
A description of the levels of doses that require protective action or assessment during optimization (DC and RL for humans; DCRL, for biota).
820 In order to clarity the meaning of “integrated manner”, the following sentence should be added. In the application of the principle of optimization of protection of the natural environment, it is important to approach it in an integrated manner, as one would the optimization of protection of workers, patients, or the public. In other words, the protection of the non-human biota should always be considered in balance with that of humans. Optimization is always implemented through a procedure aimed at achieving the best level of protection under the prevailing circumstances through an ongoing, iterative process that involves:
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