|Comments to the draft recommendations of the ICRP in 02/276/06 – 5 June 2006/08/26
1) The dose constraints for workers and the public shall be used only as a guideline or target goal for operators at each facility, and shall not be used at all as any kind of regulation rule established at the national or local level by any regulators. This shall be clearly specified in Paragraph 200, 201, 210, 211, otherwise the dose constraint will be the double and more restricted regulation rule to the dose limit. (This is the most important comment.)
2) Dose constraint is introduced for optimization of protection and it is used for single source irradiation. But, the definition of single source is not clear at all and should be exemplified to avoid the misuse and over-response.
Any individual who is irradiated from multiple sources does not stay at a fixed position, but moves here and there. In this case, even if one single source is close to one individual at one time, other sources are away from him. So the ICRP recommendation should describe on the occupancy factor, used in the former ICRP publication, together with the dose constraint.
3) The dose limits of 500 mSv for emergency, 50 mSv for occupational exposure and 5 mSv for the public are still effective in the new recommendation. This shall be clearly described in the new recommendation, especially in the paragraphs of dose constraint and dose limit. Three bands of effective dose given in Table 4 should be expressed more flexibly with wider bands in case-by-case considering these three dose limits of 500, 50 and 5 mSv.
1) If the new recommendation describes about the exposures with malicious intent like the deliberate dispersion of radioactive materials, the ICRP should also describe about the potential exposure and risk including chemical toxicity of depleted uranium bomb, since this topic has been reported in the TV program.
Takashi Nakamura, Deputy President of Radiation Council of Japan
Prof. Emeritus of Tohoku University
September 4, 2006