Optimisation of radiological protection

Draft document: Optimisation of radiological protection
Submitted by Harold Peterson, Consultant
Commenting as an individual

Comments on the Draft ICRP Foundation Document, “The Optimisation of Radiation Protection” General Comments 1. There is a high degree of redundancy in the report, particularly with regard to various definitions of optimisation, the need for stakeholder involvement, and the factors to be considered in the optimisation process. Consolidation of these elements would produce a clearer and more readable set of recommendations. 2. The document reiterates past platitudes without really furnishing any concrete guidance on how to apply the principles. ICRP Publication 37 at least provided examples of optimisation. 3. Some of the discussion, particularly the “weighting factors” mentioned in Annex 2, has the effect of increasing the complexity of the optimisation process and decreasing public comprehension, particularly since these factors are primarily arbitrary value judgments. Specific Comments Page 6, 4th ¶, 3rd line — Is the avoidance of unnecessary exposures part of the optimization process or is it the essence of the justification process? Page 7, 1st ¶ — In a similar vein, does stakeholder input properly belong in the optimisation process or in the justification and dose limitation steps? Optimisation can be applied to small tasks as well as the whole protection programme. Does the Commission intend that public input be solicited on each and every task? Page 8, last ¶, first sentence — The meaning of this sentence is not clear. Perhaps 1 or 2 additional sentences should be added to expand the concept. Page 9, ¶ (3), 3rd line — Although “the precautionary principle” has been widely adopted (by social scientists and EU statute), one can’t help feeling that, if our ancestors had adopted it, we’d still be freezing in the dark in some cave. Page 11, ¶ (9) — The association of the precautionary principle to stochastic radiation effects seems odd. As I understand it, the precautionary principle states that: 'Where there are threats of serious or irreversible environmental damage, lack of full scientific certainty shall not be used as a reason for postponing cost effective measures to prevent environmental degradation.’ The precautionary principle should be invoked when: 1. there is good reason, based on empirical evidence or plausible causal hypothesis, to believe that harmful effects might occur, even if the likelihood of harm is remote; and 2. a scientific evaluation of the consequences and likelihoods reveals such uncertainty that it is impossible to assess the risk with sufficient confidence to inform decision-making. Considering that the risks of radiation exposure are better quantified than the risks of almost any other toxic agent, it is difficult to see how the precautionary principle, which deals primarily with uncertain effects, can be invoked here. Radiation risks are quantified sufficiently to enable decision making. Page 15, ¶ 24, following 3rd sentence — It might be useful to equate the licensing action to justification of the source. Page 15, ¶ 24, last three sentences — This discussion of dose constraints is unclear. The preceding examples of exposure situations are source and pathway specific. However, the dose constraints are stated as being applicable to all exposure situations. More discussion is need to clarify this. Page 43, Annex 2, ¶ (1), First sentence — Is optimisation applied under the dose constraint or under the dose limit? In U.S. practice, optimization has been used to set dose constraints (e.g., EPA 40 CFR Part 190 [release limits for uranium fuel cycle facilities] and NRC 10 CFR Part 50, Appendix I [Release limits for power reactors]. Page 45, 2nd ¶ — Consistent with the preceding comment, the optimisation process mentioned here starts at 1 mSv. Page 46, Annex 2, 1st ¶ — This appears to be advocating setting a dose limit on accidents. The dose limit for accidents is 0. The “dose limits” for accidents are actually protective action guides or cleanup criteria. Page 47, Annex 2, 1st ¶ — The suggestion of weighting various components involved in optimisation adds a degree of complexity and pseduosophistication that is not justified by the magnitude of most of the doses to the public. Given a criterion of $100,000/person-Sv ($ 1,000 per man-rem) it would be difficult to justify the effort to compile the data just to do a optimisation analysis.