|The Optimisation of Radiological Protection
In the draft general recommendations (ICRP2005) there was reference to “foundation documents”, as then not available, that would clarify how the ICRP arrived at its proposed recommendations; particularly where there were changes. On the implementation side, the role of the optimisation principle certainly changed. From being the main principle in protection it was given a secondary role to dose constraints, individual protection taking much greater precedence over societal considerations; it was merged with a variety of control strategies, such as best available technology, depending on the application; an elaborate disaggregation of collective dose was recommended, without clear rationale; and optimisation became just a component of safety culture.
A foundation document would have provided some rationale for these changes. This document does not do that. As is noted clearly in the abstract, these changes are taken as givens; the authors take the draft 2005 recommendations as their starting point. One might therefore expect this document on optimisation to extend what we find in that main recommendations and provide practical advice on how the general recommendations are intended to be applied. Unfortunately it does not do this either.
The document largely reiterates what we find in the 2005 draft general recommendations and is very general, very repetitive, and in many sections does not express ideas clearly. My recommendation is that the document should be much shorter. The key ideas and issues concerning optimizing need to be presented. It should be a document that clearly presents the principle of optimisation; and that provides some practical applications in the various sectors – public, medicine and occupational – showing how particular issues are resolved. Throughout there should be a strong connection to the underlying principles related to radiological protection. It should not attempt to provide detailed prescriptions. It should steer clear of the confusing and unnecessary attempts to merge optimisation with the variety of descriptions of approaches to control that are found in other national and international documents. In the document it is pointed out that, in addition to the ICRP’s own publications, there are reports from other international bodies describing optimisation. It is a mistake to try to produce in this ICRP document an amalgamation of the interpretations by those various agencies in different industry sectors. The ICRP should be leading in radiological protection, not following.
Comments on the text
Para 2: This is a key paragraph. Previous advice from the ICRP on optimisation is noted as still being relevant. Words from the previous relevant documents could be consolidated here, rather than covering the same ground with different words and at greater length.
Para 3: There is no need to place the long-standing base of radiological protection – the principles of justification, optimisation and protection of the individual – as somehow derivative from what is termed the precautionary principle. In its general and useful sense this principle encapsulates the idea that the absence of complete scientific certainty should not be used as a reason for postponing decisions where there is a risk of serious or irreversible harm. The approach of the ICRP over the years has certainly included this idea. However, a different interpretation nowadays of the precautionary principle can be taken as a reason for applying undue and narrowly-focussed conservatism, which is quite counter to the principle of optimisation. (This comment applies to paragraph 9 also.)
Furthermore, with the three basic principles, and the supporting technical information on biological effects and dosimetry, the ICRP has provided over the years the conceptual and working tools for national authorities to frame protection standards and regulations to meet their particular national needs. It is up to those authorities to reflect the relative emphasis to be placed on protecting individuals and on meeting societal needs, as well as how they go about arriving at an optimum level of protection. The details of stakeholder involvement are also best left to national authorities, or at least, to other international organisations that are more directly connected with national authorities. In straying into these political areas, the ICRP may be undermining its principles and losing its leadership in radiological protection.
Para 4: “All situations where radiological exposures are amenable to control . . .” Given that “amenable” is open to interpretation, this is not a helpful description of the set of situations that will be addressed.
Para 24: It is not clear what role stakeholders might have in deciding what value a dose constraint for a particular source should have, unless the chosen value of constraint were to be a result of an optimising. Optimising, though, is supposed to take place under the constraint.
Para 27 (and elsewhere): It does not seem helpful to bring in the term “safety culture”. One has the sense that the ICRP is trying to attach the vocabulary of safety and health protection from a variety of fields to its recommendations. This is obscuring clarity.
Para 39: The recommendation for the control of emissions appears to be to use BAT, with due consideration to social and economic costs. (This point also arises at length in Annex 2, section 2.) Is the ICRP, concerned as it is with radiological protection, now recommending an approach that is not health-related? The ICRP, in its Publication 77 (1997), had correctly pointed out that BAT falls short of optimisation. Paragraph 7 in that document states “There has been increasing pressure for the adoption of policies described by labels such as ‘best available technology’ or ‘best available technology not involving excessive cost’. The term ‘best available’ has usually implied ‘best’ from the environmental viewpoint, regardless of cost. The addition of ‘not entailing excessive cost’ brings the concept closer to the Commission’s recommendations to keep doses as low as reasonably achievable, but involves costs only when they are becoming excessive. These policies fall short of achieving the optimisation of protection.” Is the addition of the phrase now in this draft document “with due consideration to social and economic factors” an attempt to make the application of BAT health-related, and really optimisation of radiological protection? Or has the ICRP succumbed to the pressure noted in Publication 77?
Para 74 et seq.: Assigning responsibilities and advocating a safety culture seems to be going beyond the role of the ICRP.
Annex A1: It is not clear how statements including “should” or “must” in this annex (and the other annexes) are to be interpreted. Are such statements to be taken as new recommendations by the ICRP? Is citing a recommendation by another agency (e.g., the IAEA’s recommendation on the involvement of health physicists in interventional radiology) an endorsement by the ICRP? If so, such recommendations need to be made unambiguously in the main text, not in annexes.
Annex A1, Section 2: The discussions here are an uncomfortable mixture of generalities and industry specifics; particularly European specifics. It is difficult to see how the section will help in any of the areas of occupational exposure covered. If historical trends are to be included it would be better to cite worldwide values (from UNSCEAR for example). It is not clear, though, what the purpose is in citing the historical trends in the nuclear industry sector.
Annex A2, Section 2: As noted earlier, the attempt to line up BAT with optimisation of radiological protection seems a mistake. It would be far more helpful for the ICRP to continue its emphasis on radiological protection and to point out clearly where control strategies such as BAT depart from optimisation of radiological protection.
Annex A2, Section 3: Despite all the detail given in the main text (para 60 et seq.) on the ways in which collective dose can be disaggregated, there is no guidance on the “environmental, technical, economic and social considerations and values (para. 73) that are to be applied to the matrixed doses. What radiological principles are involved here? Is LNT the issue? Is it just to be left up to stakeholders? In this section of Annex 2, the suggestion is that indeed the weighting of the disaggregated components in the dose matrix could be “based on stakeholder considerations”. The reader is left hanging; future doses might be given a higher weight or a lower weight for example. This section does not appear to be an advance on what the ICRP has written previously on this topic with one exception. That is the very clear recommendation at the end of the Annex 2 section on relative weighting of future doses (illustrated in Figure 7, not Figure 4) that “predicted doses beyond a few generations into the future should not play a major part in decision-making processes.” This is a significant recommendation – it should not be buried in an annex.
Annex A3: The text generally follows that of earlier ICRP publications on radon, with a slight modification of the recommended action levels for consistency with the draft ICRP 2005 recommendations. The introduction on the harmful effects of radon could cite ICRP’s own publications, rather than the EPA’s, and it might be helpful to cite also the two recent papers (Darby et al., Krewski et al.) on the combined analysis of European studies and the combined analysis of North American studies, both of which provide direct evidence for effects on health at residential levels.