The present draft is a great improvement from previous versions. The Commission has called attention to chapters on which further guidance would be welcome. Such indications are shown on pages 15, 50, 52, 53 and 70. Comments will be given on these requests but also on a few inconsistencies elsewhere in the draft.
Guidance request, page 15
The sections on scope, exclusion and exemption seem adequate.
Guidance request, page 50
The term justification is not included in the glossary. It is a general term, but is used here in a restricted sense. ICRP does not approach the question on whether a radiation practice is justified if there is an adequate non-radiation practice achieving the same result. This may surprise the reader. It would be advisable to address the question directly as was done in paragraph 115 in ICRP Publication 60, the second half of which read:
"The Commission recommends that, when practices involving exposure, or potential exposure, to radiation are being considered, the radiation detriment should be explicitly included in the process of choice. The detriment to be considered is not confined to that associated with radiation ¨C it includes other detriments and the costs of the practice. Often, the radiation detriment will be a small part of the total. The justification of a practice thus goes far beyond the scope of radiological protection. It is for these reasons that the Commission limits its use of the term justification to the first of the above stages, i.e. it requires only that the net benefit be positive. To search for the best of all the available options is usually a task beyond the radiation protection agencies."
Guidance request, page 52
Guidance is sought on the adequacy of the treatment of the topics of optimization and representative persons. Comments on the later text on optimization, section 5.8.7 will follow.
Guidance request, page 53
The section on dose constraints seems adequate.
Guidance on section 5.8.7
Paragraphs 229¡ª231 should be amended.
Paragraph 229: This is a remnant from previous drafts. The statement that the collective effective dose ¡±is not a useful tool for making decisions because it may aggregate information excessively¡± is not correct. In the use of the collective dose as one of the tools for optimization of protection, the individual doses must be lower than the dose constraint. At such low doses there is no scientific reason not to aggregate the information. All that is said about making an analysis based upon the identification of different population groups can only be defended by a wish to discriminate between groups (¡±we¡± and ¡±they¡±), a practice that might seem advantageous to ¡±us¡± but is discriminating to ¡±them¡±. It would only be acceptable if some doses were high and other doses low, but in the cases at hand all doses are very low.
The only case where aggregation might be scientifically acceptable is when some of the very low doses are expected in a distant future. However, that particular problem should be treated separately. It should also be remembered that playing down the significance of doses at great distances in the long run may invite installations to disperse rather than concentrate their releases of radioactive materials, an unpleasant prospect. The paragraph should be deleted.
Paragraph 230: This could be seen to be in conflict with paragraph 147. Some more cautious wording in both paragraphs should solve the problem.
Paragraph 231: Is there really support for saying ¡±increasing uncertainty of the relevance of very low doses and doses received in the far future¡±? The statement seems more subjective than objective. To ¡±give more weight to moderate and high doses and to doses received in the near future¡± would not be in line with ICRP¡¯s policy. This statement seems political rather than scientific.The Commission has previously been cautious about discriminating against future doses, but has recognized the uncertainties and the doubtful significance of doses in the very far future. Instead of ¡±giving more weight¡± to high doses and doses in the near future, it would be more in line with ICRP policy to ¡±give less weight¡± to doses in the very distant future.
Guidance request, page 70
Only minor comments. The last two sentences of paragraph 286 are not clear. ¡±Intakes of radionuclides ... are more.¡± ?? And ¡±this source¡± in the last sentence would not include 40K.
In paragraph 287 ¡±geography¡± seems redundant when geology, lifestyle and building construction practices are mentioned.
Guidance on section 4.5.7 (Collective dose)
Paragraph 146: Following the discussion above on paragraph 229, it is suggested that the two first sentences of paragraph 146 are added to paragraph 145. The remainder of the paragraph should be deleted.
Paragraph 147: As mentioned in the discussion on paragraph 230 above, there may be a need for a slight revision of the two paragraphs to avoid apparent conflicts. The words ¡±is not reasonable¡± should be replaced by ¡±may not be appropriate¡±, they seem unnecessarily offensive.
Paragraph 148: In the light of the previous discussions, this paragraph should be deleted. The use of the suggested integration does not seem to be appropriate.
Guidance on paragraphs 167 and 174.
The distinction between ¡±public exposure¡± and ¡±exposure to members of the public¡± is not clear and should be better explained. ¡±Public exposure¡± as described in paragraph 167 would expose both radiation workers, patients and members of the public. Radiation workers and patients are also members of the public. It is not clear if the dose limits relate to doses from public exposures or to doses to members of the public, and the possible difference is not discussed.
Guidance on Table 4
The text in Table 4 should be checked. It is not true that annual doses below 1 mSv always come from ¡±a source that gives them no direct benefit¡±. Exposure from consumer products is one example. It is doubtful if one should say that exposures in the range 1¡ª20 mSv come from exposure situations that lead to ¡±direct benefit¡±. It is true that it is a direct benefit to live in a house but certainly not to be exposed to radon in that house. It is doubtful if Table 4 is of use to the reader.
Guidance on section 10.2
The usefulness of Reference Animals and Plants is doubtful. It is hardly scientific and probably not useful, however it is a venture in which the Commission is now obviously engaged. A word of warning might be appropriate.
Guidance on the glossary
Glossaries are often poorly favoured and should be thoroughly checked. In the present glossary the formulas under the entry ¡±Collective Effective Dose¡± are not warranted and are inappropriate in the light of the above discussions. They should be deleted. To say that the collective dose is ¡±the sum of individual effective doses¡± is incorrect. If this were the case, its unit should be sievert and not man sievert. The correct definition is given in the third sentence of paragraph 145: the product of the number of exposed persons and their average dose.
There is no reason to call the ¡±Committed Radiation-Weighted Dose¡± anything but ¡±Committed Equivalent Dose¡±.
At a number of places the Greek letters are not given but for no obvious reason replaced by ¡±¡õ¡±.
The definition of ¡±dose limit¡± should be more stringent formulated to avoid confusion with dose constraint. It may suffice to insert ¡±all¡± before ¡±planned¡±.
ICRP 60 ¨C Annex C
I have heard several people express the view that a presentation of the scientific basis for the selection of limits and constraints, like Annex C of ICRP Publication 60, is missing, both as an Annex and a corresponding condensed presentation in the main text.
My main point relates to paragraph 229. However, the Commission should be congratulated to a greatly improved text.