|I am sorry that just now I had the opportunity to read the ICRP draft on "The scope of radiological protection regulations". It is an excellent document. I do believe that, as important as defining levels of concern, is the definition of levels of no-concern, mainly for regulatory bodies. The way the document particularly deals with candidates to exemption is precious. But, of course, I am not writing to you just to say it is a good document. I have a point of concern about the guidance provided by the document.
My point is related to aspects related to exposure to natural radiation. Brazil has several high background areas and I can foresee problems to accept some of the documents recommendations. The main subject is related to building material.
It is not clear, by the text on the document, why building material, as a whole, has been excluded from the context of commodities.
I was really surprised to see that building material is now recommended to be treated by a different approach than that accorded in the difficult process of "getting agreement" during the development of the document "Application of the Concepts of Exclusion, Exemption and Clearance Safety Guide", Safety Standards Series No. RS-G-1.7 published by IAEA on 2004, based on the request from the General Conference of the IAEA to the Secretariat to develop radiological criteria for long lived radionuclides in commodities, particularly foodstuffs and wood (Resolution GC(44)/RES/15). This document was developed in a process that involved experts from 26 Countries and has been approved by the 4 IAEA Safety Standards Committees (42 Countries plus 20 international organizations, including ICRP).
Although RS.G.1.7 recognized that some building material could warrant further control, as stated on its para. 5.1, below,
"... However, there are some situations (such as the use of some building materials containing natural radionuclides) for which exposures from materials due to radionuclides with activity concentrations below those given in Table 1 would necessitate consideration by the regulatory body for some types of regulatory control. Regulatory bodies should retain the authority to investigate such situations and to take whatever action is considered necessary."
the new approach provided by ICRP extend the need of control to all building material, based on examples of material that would obviously already be inside the scope of regulation (e.g., para.98 cites a 226Ra concentration of 4500 Bq/kg, and para. 100 cites doses up to about 100 mSv, that could hardly be associated to a 1 Bq/kg of natural radionuclides in any building material).
The inclusion of the equation strongly affects the simple accepted criteria of 1 Bq/kg for all commodities and may create unnecessary overload to regulatory bodies from Countries with high background areas. The arguments cited in Section 6.3.1 are not consistent enough to remove building material, in such general way, from the context of levels agreed for all commodities and need to be revised, to address specific situation where the levels set for commodities would lead to unacceptable doses or to the real need of controlling such doses, or be removed.
I know I am some out of date to comment the document but I hope you can think about this point while revising the document.
Using this opportunity, I would also like to suggest minor revision on two other topics: (a) para.(f) of the Executive Summary should be revised on the sentence "...for radionuclides of artificial origin, it is recommended that substances containing activity concentration of less than around 1 Bq per kilogram ...." as these levels are supposed to apply to radionuclides of natural origin (including building material, in general!); and, (b) it is not clear why on Executive summary, para. (i) cites exemption levels for indoors radon and para. 109-110 a different level for exclusion for radon is recommended. Using two levels for not controlling the same question may lead to confusion and misunderstanding. Besides, excluding at the average worldwide level would mean that half the world would not be excluded from regulatory control regarding indoors radon. I do believe that this "exclusion" in not really necessary, as the use of exemption would be much more adequate and reasonable.
I am really sorry to be out of date for these comments but I thought the subject relevant enough to try comment before final revision and publication of the document.