Over recent years, the international community has built up a framework for radiation safety that is largely consistent among States, fit for purpose, and robust. ICRP can take much credit for this through the quality and appropriateness of its Recommendations and, in particular, the landmark Publication 60. The International Basic Safety Standards (BSS) has made a major contribution also, especially for those States that have updated their national regulatory systems in the last few years, many with IAEA assistance. The IAEA's contribution stems from its statutory responsibility for establishing safety standards, which it has carried out since the 1950s. The IAEA Board of Governors stated as long ago as 1960 that: “The Agency’s basic safety standards … will be based, to the extent possible, on the recommendations of the International Commission on Radiological Protection (ICRP)”. Since that statement was made, successive revisions of the Basic Safety Standards have indeed been based on the ICRP recommendations, with the consequence that there is substantial harmonization of national approaches to radiation protection throughout the world. There is much value in preserving this degree of harmonization and therefore the IAEA, in conjunction with its advisory committees on Safety Standards, will need to give careful consideration to the adoption in future editions of the BSS of any proposed new ICRP recommendations.
The draft 2006 ICRP recommendations were issued for comment in June 2006 and take into account the comments provided to the ICRP from its first round of consultation on the earlier 2005 draft. The comments that are given below have been prepared by the radiation safety professionals of the IAEA Secretariat with the aim of assisting ICRP in the development of recommendations that could be used as the basis for improvement in the Agency’s safety standards and thereby preserve international harmonization. In this context, it is noted that the IAEA Safety Standards form the basis for regulations in many of its Member States, and therefore any significant change to the Safety Standards may well imply a major cost to Member States. The case for stability in international standards is strong, and there should be a clear margin of benefit when justifying proposals for change.
1. The IAEA professionals welcome the openness of the approach adopted by ICRP with respect to its proposed 2006 recommendations and are grateful for the opportunity to comment on the draft.
2. The ICRP should be as clear as possible in explaining the concepts and philosophy behind the development of its recommendations. In addition, the essential recommendations should provide for some flexibility to national authorities in applying them.
3. The ICRP should do its best to avoid confusion and misunderstandings. Therefore, it should avoid mixing concepts and the use of words that cannot be unambiguously translated into another language or that have a different meaning in another language. For example, ‘constraint’ may be very similar to ‘limit’ in some languages, or even stronger than 'limit'. The way to solve this problem is to ensure that there are full, clear and unambiguous definitions of key terms and concepts: the words and phrases can then be properly translated into any language.
4. The focus of the 2007 ICRP recommendations should be on clarifying key issues and, in particular, those that have been problematic. For example, ‘exclusion’ should include ‘unwarranted control’ in addition to unamenability to control as a possible criterion. National authorities must determine what is important and what is unwarranted.
5. As remarked last time, the IAEA professionals welcome the intention of ICRP to clarify its guidance on practices and intervention, recognizing that there has been some debate over the use of these terms since the publication of the 1990 recommendations. However, they feel that the current text still falls short of the desired degree of clarity. Additional terms have been introduced (such as: endeavour, undertaking, planned situation, existing situation) that, as presently defined and used, do not necessarily improve clarity.
6. Again as previously remarked, the ambition to simplify the protection system and to reduce, where appropriate, the number of separate criteria for protection is welcomed. However, it is difficult to see that the desired simplification has been achieved. A detailed critique is presented below.
7. The ICRP should emphasise the application of its basic principles: Justification; Optimization of protection; and Limitation of individual doses. Experience has shown how optimization of protection has improved radiation protection outcomes for some industries and technologies. Constraints provide a desired bound for the optimization process. Some technologies are able to satisfy constraints that are set at a low level, while others are only able to meet constraints set at a higher level: this is normal, and should be reflected in the freedom of national authorities to authorize dose constraints that are appropriate for particular circumstances. The ICRP should be wary of recommending specific values of dose constraints, in order to avoid an unintended rigidity developing in future national implementations of its recommendations.
8. The 2006 draft does not make a convincing case for ‘new’ recommendations. Nowhere does the draft claim to bring improvements in safety. Rather, the rationale given relates to simplification and clarification of existing recommendations. However, whether the 2006 draft is simpler and clearer than ICRP60 is debatable. If current regulatory paradigms are retained, as is highly desirable (and possibly a consistent interpretation of the draft text), then it would seem preferable to emphasize stability and continuity by referring instead to ‘updating’ ICRP60 recommendations. The tone of language surrounding 'new' recommendations creates both an expectation that may be unfulfilled and an unwarranted anxiety. Such negative impressions are unnecessary and unhelpful – especially to the ICRP's reputation. The crucial new ideas – avoidance of highly undesirable risk in existing and emergency situations, and voluntary reduction of exposure below action levels – are not clearly explained.
9. The introduction of the terms 'existing exposure situation' and 'emergency exposure situation' is supported. This brings a welcome improvement in clarity to the awkwardness with 'intervention': the essential problem being that 'intervention' (an action applied to a situation or activity) is not the counterpart to 'practice' (an activity to which regulatory actions are applied). Similarly, the term 'tissue reaction' is felt, on balance, to be an improvement on 'deterministic effect', especially with regard to improving clarity among the medical profession where tissue reactions can legitimately be considered in a stochastic context. Replacement of 'practice' by 'planned situation' is less attractive, since the latter is inherently less precise than the well-established concept of 'practice'. Taking a trip by air could be considered a planned situation: does this mean that it should be treated as a practice and the public dose limits, dose constraints, and the requirement to optimize protection applied?
10. Chapters 3 and 4 provide a good overview of the biological and dosimetric bases for radiation protection practice. The arguments for continuing to adopt LNT as an assumption for the purposes of establishing radiation protection measures are noted, and the caution against misusing the assumption (paragraph 57) is welcomed. The recommendations related to risk of hereditary effects and radiation-weighting and tissue-weighting factors will keep the published 2007 Recommendations up-to-date with the latest scientific information.
11. The increased emphasis placed on source-related restrictions on exposure is also welcomed, since it is the source (or the exposure pathway) that can be controlled. For activities that are now known as practices, this recognizes current practice in many parts of the world and sensibly focuses regulatory attention on sources rather than on the people exposed. However, for exposure situations currently dealt with through intervention, the imposition of the dose-constraint paradigm for practices – as ICRP appears to suggest – would create a regulatory upheaval, without a sound case being made by ICRP for the merit of such a change. This is the proposal, if correctly understood, that causes the greatest anxiety among IAEA professionals, as it implies major change to regulatory practice, leading to significant implementation costs with no corresponding quantum of benefit. On the contrary, on some interpretations of the text, the new recommendations for dose constraints in existing and emergency exposure situations could run counter to the principle of optimization of protection. However, as the text is less than completely clear, it may be that an alternative interpretation implies retaining the existing regulatory paradigm while attempting to unify the underlying philosophy. An explanation is provided below.
12. For ‘practices’ (using current terminology), which is where the overwhelming majority of regulatory control measures are applied, the ‘new’ recommendations are scarcely distinguishable from the old. The most significant change seems to be implied, rather than explicit. This relates to the proposals for placing greater emphasis on dose constraints than at present. Such a proposal can be supported because it directs regulatory attention to source-related restrictions on exposure. Regulations normally place obligations on those responsible for the sources, rather than on the people exposed. An inevitable consequence (and a phenomenon that is already occurring in practice, although sometimes not openly acknowledged) is to make use of dose constraints both prospectively (in design) and retrospectively (in assessing performance against regulatory criteria). Constraints are not limits, but they do serve as reference levels. The text of the 2006 draft continually refers to constraints in a prospective context, as in ICRP60, presumably to counteract possible criticism that the concept is being modified (see eg: paragraph 197). However, this is disingenuous. Constraints cannot provide ‘the most fundamental level of protection’, as the 2006 draft claims, unless there is some retrospective assessment of safety performance against them. Occasionally, the draft appears to acknowledge this (see paragraph 174). A recognition that constraints are de facto used in this way would be welcome, but essentially reflects an increasingly common practice. It should be emphasized that any such retrospective use should not be for legal compliance purposes, but rather as an indication that protection measures, or the optimization assessment, may need to be reviewed.
13. For other circumstances of exposure (for which the terms ‘emergency exposure situation’ and ‘existing exposure situation’ are proposed), there appears to be a reversal of the current regulatory paradigm. The present, and eminently sensible, regulatory approach is to ‘intervene’ in such exposure situations only when there is merit in doing so, and this is put into effect through the use of action levels. If exposures occur above the specified action level, action to reduce them is expected, or at least to be considered. The overwhelming majority of such situations are not actively regulated because such control is unwarranted: exposures remain below the action level. (Contrast this with the approach for practices, where the default is to regulate every practice because it introduces new, controllable exposures, and to release a practice from regulatory obligations only through exemption from otherwise applicable requirements.) The 2006 draft (see eg: paragraphs 33, 192, 195, 278 and 279) could be interpreted as recommending that action levels should be replaced by dose constraints, below which protection should be optimized. This would have the effect, in principle, of applying regulatory controls (such as the requirement to optimize protection) to every circumstance of exposure, including those that presently are not actively regulated. This would turn current regulatory practice on its head and cause a huge and expensive disruption while new regulations are developed and implemented. And it is not clear that such regulations would be workable let alone yield a net benefit. The current system based on action levels and intervention levels works well, and is understood by IAEA Member States. The 2006 draft does not say why the Commission sees a need for change or what benefit such a revolutionary change would bring. If there is a genuine reason for change, it must be clearly motivated and articulated. Paragraphs 13 and 192 appear to hint at a justification, but they are wrong in suggesting that optimization of protection does not currently apply to interventions; indeed, it is curious that the ICRP gives the impression that it is not aware of its own existing recommendations.
14. However, closer analysis of the text of the 2006 draft suggests that the above interpretation may not be intended, and it is most unfortunate that the draft is unclear on this point. It is doubtful that ICRP seriously intends such a radical change to regulatory practice. The alternative interpretation of the 2006 draft (see eg: paragraphs 201, 301 and 348) is that action levels should be set through national or local processes of generic optimization within a defined range, the upper bound of which could be called a constraint. This would preserve the current regulatory paradigm for existing exposure situations. If this is the correct interpretation, then the 2006 draft recommendations for regulation of existing exposure situations are, just as for practices, essentially the same as those given in ICRP60 and the need for ‘new’ recommendations is brought further into question. Furthermore, it is difficult to see how renaming the upper bound of the range of action levels as a constraint is a simplification or that it adds value to the current system, unless the purpose of the constraint is properly explained: that is, to introduce a new requirement for protection in existing exposure situations – avoidance of a region of risk that is considered to be highly undesirable. This is akin to, but without the regulatory force of, a limit.
15. It may be that what ICRP intends is that voluntary action (not a regulatory requirement) to reduce exposures below an action level is now recommended. This would be perfectly reasonable and, no doubt, desirable in some cases for radon in homes, for example. But, if this is indeed the intent, the current text does not make it clear. This lack of clarity reflects a more general problem in that, where regulatory requirements are implied, the draft sometimes does not specify who has the responsibility to take action in a particular circumstance. Simply stating that protection should be optimized below a dose constraint is unhelpful: for example, for radon in dwellings, is it the regulator (in setting action levels), the builder (in meeting building standards), the homeowner (in reducing high levels), or some other party who should perform the optimization?
16. The propossed shift from action levels to dose constraints in existing exposure situations may have consequences that run counter to the principle of optimization of protection. First, on one interpretation, the 'entry level' into the system of protection is (as proposed) drastically reduced – for example, for radon in workplaces: from 1000 Bq/m3 (in most countries) to 40 Bq/m3 (see paragraph 294). If regulatory intervention is broadly justified on optimization of protection considerations at or around 1000 Bq/m3, it is virtually certain that its cost would not be warranted at levels as low as 40 Bq/m3. Thus, the requirement to optimize protection at such low levels would itself not be an optimum regulatory measure. Second, on another interpretation, dose constraints represent 'a level of dose where action is almost always warranted' (see eg: paragraphs 33 and 219). Since failure to comply with dose constraints is highly undesirable – 'all reasonable efforts should be made' to avoid exceeding them (paragraph 302) – there could be a tendency by regulators to set constraint values rather high. There is then a risk that protective measures could be less effective than those currently accepted using action levels derived from optimization considerations. Action levels (as distinct from dose constraints), at lower numerical values, could provide better protection and be more in keeping with the principle of optimization of protection.
17. In taking an overall view of Chapter 5 onwards of the 2006 draft, it seems to be the result of an exercise in exploring an alternative approach to radiation protection that has continued on to development of recommendations without paying sufficient attention to ‘reality checks’ of the value of or the need for the ‘new’ recommendations or whether they meet the declared objectives. It may be that the desire to ‘unify’ the protection approach for practices and other circumstances of exposure has its origin in a perceived need to improve the understanding of the non-specialist, rather than for the benefit of the regulator or health physicist, who seem comfortable with the ICRP60 paradigm. The ‘unification’ idea may serve a purpose in illustrating a coherent underlying philosophy, although this is already implicit in current recommendations. To be clear: the current and the ‘new’ paradigms have the following common features:
1) do the best you can in the circumstances (optimize protection);
2) avoid ‘unacceptable’ or ‘highly undesirable’ exposures; and
3) only apply regulatory controls when warranted, that is, when above a defined ‘entry level’ into the regulatory system.
For practices, protection should be optimized below constraints that mark the lower bound of what is normally unacceptable as additional exposure caused by the practice. For other circumstances of exposure, protection should be optimized first by establishing action levels, related to existing or projected exposure, that ensure that a regulatory requirement to reduce exposure is warranted and second, when taking action to reduce exposure, by doing the best one can in the circumstances.
The genuinely new regulatory development in the 2006 draft – although it is not presented as such – is to introduce dose constraints for bounding the optimization process in existing situations in addition to the use of action levels that mark the entry level into the regulatory system. Instead, the dose constraints are said to replace the action levels, which of course they cannot. Using the term ‘constraint’ to mark the upper bound of the recommended range of numerical values for action levels could then be a strategy for resolving the inconsistency between the 2006 draft and ICRP60. The exposure could then be said to be optimized below the constraint, although the constraint might play only a nominal role with regard to the regulatory arrangements applied to any particular existing exposure situation, since optimization is required above the action level in any case. Furthermore, this would not require significant change to the BSS or to national regulatory systems already in place.
18. The draft would benefit from a thorough editorial review. Unfortunately, there are several instances of internal inconsistency and one or two significant inaccuracies. Some of these are pointed out in the detailed comments below.
In summary, when comparing the 2006 draft with the declared objectives for a new Recommendations publication, the IAEA professionals feel that, while there are many improvements over the 2005 draft, those objectives have not yet been fully met. Further, regulatory practices derived from the most desirable interpretation of the recommendations would appear essentially unchanged. A possible wise course of action for ICRP in these circumstances is not to continue promoting ‘new’ recommendations, but to emphasize the updating of existing recommendations. In particular, this would mean avoiding the confusion caused when talking of applying the regulatory model for practices to existing exposure situations and, instead, consolidating current good practice through clarification where necessary. A genuine improvement in clarity, together with the many updates to the chapters on biology and dosimetry, would be sufficient to justify publication of the 2007 Recommendations.
The IAEA professionals are conscious that the majority of comments made are critical rather than complimentary. This is a natural and commonplace experience when requesting feedback on a draft document: the good points generally pass without comment. The IAEA professionals wish to emphasize their strong support for the role of ICRP in establishing the underlying ethical and scientific basis for radiation protection practice, but invite ICRP to give consideration to the desirable extent of its recommendations for detailed implementation of regulatory measures. In particular, ICRP could bear in mind the existence of the International Basic Safety Standards and other publications in the Agency's Safety Standards Series when considering the need for ICRP recommendations on regulatory or implementational topics.
SPECIFIC COMMENTS BY PARAGRAPH OR SECTION (excluding ‘editorial’ comments)
Preface; paragraph 9; and paragraph 11: Reasons given for developing new recommendations include: (i) ‘consolidation and rationalisation’ of separate recommendations contained in several existing ICRP publications (see Preface of the 2006 draft); (ii) the implied need to simplify what ICRP perceives as a complexity of existing recommendations (see paragraph 9); and (iii) a need to clarify how the radiation protection principles are applied (see paragraph 11). These are hardly good grounds for new recommendations. In fact, (i) and (iii) explicitly involve clarification of existing recommendations. Further, (ii) would only be valid as a reason for change if the new recommendations were indeed simpler than the existing ones.
Preface and paragraph 8: With regard to the ‘consolidation and rationalisation’ argument, the 2006 draft claims that there are presently 30 or so numerical values for restriction on dose in its current suite of publications (paragraph 8). On closer examination, however (see IRSN Report No277), the number of distinctly separate numerical values is nearer to 20 and half of those relate to the relatively rare special cases of emergencies and medical research. For common use, for practices and existing exposure situations, the number of numerical values of dose related to recommendations for regulatory control is about 10, and all (with some debate) are defensible . Furthermore, the 2006 draft specifically states that all the existing numerical values remain valid (see paragraph 12). Consequently, rather than reducing the number of different values, the 2006 draft could be said to introduce additional reference points in the form of the band boundaries in Table 4. Moreover, instead of reducing the number of separate special terms, the 2006 draft introduces additional ones, such as ‘planned exposure’, ‘endeavour’ and ‘undertaking’ (while retaining ‘practice’), and ‘emergency exposure situation’ and ‘existing exposure situation’ while retaining ‘intervention’ (see paragraph 348).
paragraph 12: This paragraph states that there is no need for any fundamental change to radiological protection regulations, and yet the proposed extension to the role and application of dose constraints in replacing action levels is very much a fundamental change.
paragraph 30: The statement of the principle of optimization should be made more precise; it reads more like an explanation of the principle.
paragraph 37: This states blandly that the distinction between practices and intervention has been seen as artificial. No explanation for this is given, nor any indication of who sees the distinction as artificial. Indeed, many would argue that the distinction is natural and unavoidable. A major issue with the BSS is the identification of all those situations that should be covered by the requirements for practices. The danger with removing the distinction between practices and interventions is that the component of exposure that is introduced by a practice and can be readily regulated becomes mixed up with the component that cannot, and this confusion is demonstrated in the text on scope. The Commission should make it clear that it is the practices (by whatever name) that can be more readily and justifiably subjected to regulatory control.
Section 2.4: The text should more clearly explain that, while exclusion and exemption are conceptually different (and complementary) mechanisms for defining the scope of radiation protection measures, there is some overlap in practice whereby, in some national systems, exclusion will be used to a greater extent while, in others, exemption will be the more widely used mechanism. The important message to get across is that some things will always be addressed through exclusion (see examples in paragraph 44), while others will always be addressed through exemption (eg: situations needing to be assessed case-by-case). However, there is a ‘middle area’ which could be addressed through exclusion or (generic) exemption. The 2006 draft should make it clear that this flexibility allows for national preferences of legal and regulatory style.
paragraph 45 and paragraph 46: These paragraphs are too vague about the use of the 10 µSv/y criterion for exemption and imply, still, that 10 µSv/y is the basic criterion. This is incorrect, and clearly not the case for natural sources of exposure, where a figure of 1 mSv/y is considered more appropriate in many countries. It should be made clearer that the figure of 10 µSv/y is the lowest value that should be considered.
paragraph 47: The concentration levels for radioactivity in foodstuffs published by the Codex Alimentarius Commission are guideline levels for radionuclides in foods contaminated following a nuclear or radiological emergency. They are not general exemption levels for foodstuffs.
paragraph 52 and paragraph 93: Replace ‘absorbed dose’ with ‘RBE-weighted dose’ to be consistent with the report of Committee 2 on dosimetric quantities.
paragraph 53: Annex A (attached to the report of Committee 2) does not provide threshold values for severe deterministic effects: IAEA TECDOC-1432 provides a complete set of such thresholds and their basis.
paragraph 159: This seems to be first time that ‘constraint’ appears in the main text. It’s a good place to define it, or at least include a forward reference to paragraphs 184 and 185.
paragraph 162: extend definition of existing exposure situations as follows:
• existing exposure situations are exposure situations that already exist when a decision on control has to be taken, including natural background radiation and residues from past practices that were operated outside the Commission’s recommendations and from past emergencies.
paragraph 167: It is suggested that the second sentence be deleted, as this is not treated as public exposure.
paragraph 169: Three categories of exposed individuals are distinguished: occupational, public and patient. This is the current classification used in the BSS. However, the 2006 draft then proceeds to use the word ‘worker’. This word and ‘the public’ are then further defined by the words ‘informed individuals’ and ‘general individuals’, respectively. These further qualifications are unhelpful. Workers are not necessarily informed about radiation, and there seems no value in introducing the clumsy and imprecise alternative phrase for ‘the public’.
paragraph 170: A radiation worker is defined here as any person who is employed, whether full-time, part-time or temporarily and has recognized rights and duties in relation to occupational exposure. The BSS does not use the term ‘radiation worker’, as it was found to be unhelpful, although it has been used in the past. If it is re-introduced, then its definition and use will need to be made much clearer – in particular, with regard to the term ‘occupationally exposed person’.
paragraph 171: This refers to ‘controlled areas’ but not to ‘supervised areas’. The latter needs to be dealt with somewhere. What is the status of a ‘worker’ in a supervised area – a member of the public?
paragraph 173: It would help to give a rationale why ‘Relevant constraints should be higher than those for individuals in the general population’, and to replace ‘should’ by ‘may’.
paragraph 187: This is too vague and is therefore unhelpful. Better guidance is available in the BSS and the IAEA Safety Guide RS-G-1.1.
paragraph 189: This paragraph is unclear, and seems to have not recognized that existing situations can also sometimes be controlled by acting on the source – for example, by removing contamination. It also appears to support the continued use of action levels to mark the boundary of what is justifiable.
paragraph 191: This states that medical exposure of patients calls for a different and more detailed approach to the process of justification. This really does not add anything and indeed may not be correct; the justification for building a nuclear power plant may well be very detailed.
Section 5.8: While the material on optimization of protection makes reference to the well-developed methodologies described in ICRP37 and ICRP55, these now appear to take second place to a more qualitative approach: a way of thinking or of dialogue with stakeholders ('Optimisation is a frame of mind' – paragraph 221). On one hand this allows highly experienced regulators and practitioners wide latitude but, on the other, it complicates practical implementation of the optimization principle in countries still developing their regulatory systems. The latter would prefer more concrete recommendations. The draft foundation document on optimization does not help in this regard. The text does not explain how what is proposed is ‘broader’ than the ‘social and economic factors’ currently recommended, which clearly already include factors such as stakeholder involvement.
Section 5.8: Despite the proposed changes to the concept of dose constraints, there remains confusion over the role of dose constraints, even in their current application to practices. In paragraph 195, the Commission refers to the use of constraints to reduce the inequities inherent in the optimization process, but elsewhere reference is also made to the use of dose constraints as a tool for source-related protection as opposed to individual-related protection (see for instance paragraph 198 and paragraph 216). The Commission has not used this valuable opportunity to clarify and distinguish between these two roles, and instead they continue to be muddled together and thus a source of confusion. The use of constraints to reduce inequities is relevant in both occupational and public exposure, whereas the use of constraints as a tool for protection against multiple sources really applies only to public exposure. In an occupational exposure situation, all the major sources are usually identifiable and quantifiable (contrary to what is stated in paragraph 183) and, for a given type of operation, there is no need to impose restrictions on each source individually (and indeed there could be significant drawbacks). In addition, dose constraints may often be set on the basis of known good practice – there is no reason to be bound by 20 mSv/y if it is clear that a practice can comply with a dose constraint of 5 mSv/y. Using the one term – constraint – to cover all three meanings may confuse. Perhaps a qualifying adjective could be considered to distinguish between an equity-based constraint, a good-practice constraint, and a multiple-source constraint?
paragraph 201: Suggestion: expand the discussion of ‘risk constraints’ to emergencies, for which protective and other actions, in order to be effective, must be taken before or shortly after the start of a release or exposure.
paragraph 201: This paragraph makes the suggestion that a dose constraint (when applied to emergency or existing situations) could be higher than any dose limit. This is sure to cause confusion, as dose constraints for practices are supposed to be set below the dose limit and as dose limits do not apply for emergency and existing exposure situations (paragraph 186).
paragraph 202: Here the extension of the use of dose constraints results in a recommendation that seems to be based on the significance of data observed in epidemiological studies. This implies that if such studies become more powerful and show a statistically significant risk at doses below 100 mSv, the maximum value for a dose constraint should be reduced. This not only introduces instability in the recommendations, but also runs counter to the fundamental principle of adopting LNT: it is the magnitude of the (assumed or observed) risk that is important, not whether epidemiological studies yield significant results at that level.
paragraph 204: Last sentence: ‘The corresponding doses would represent a marginal increase above the natural background and are at least two orders of magnitude lower than the maximum value for a constraint, thus providing a rigorous level of protection.’ This is obscure and needs clarification. How can a dose provide a rigorous level of protection?
paragraph 204-paragraph 206 and Table 4: The usefulness of this table and related discussion is questionable. The examples given are few, leaving many other situations without clear guidance, except within very broad (and therefore unhelpful) bands, and sometimes without a clear indication of which band applies. For example, it is unclear which band the remediation of legacy waste sites should occupy. Attempts to be categorical in Table 4 create inconsistencies and contradictions; for example:
• radionuclides in consumer products should be in the lowest band, but it is not true to say in this case that there is no direct benefit to the individual;
• accident situations, in the middle and upper bands, do not necessarily represent exposure situations giving direct benefit to the individual – it is likely to be the intervention, not the exposure situation, that provides the benefit;
• the maximum constraint of 20 mSv ‘in a year’ in the middle band is not consistent with the maximum dose limit of 50 mSv in a single year. Compliance with the latter should not preclude a worker from receiving more than 20 mSv ‘in a year’. Similarly, in the lowest band, compliance with the public dose limit does not preclude a member of the public receiving a dose of more than 1 mSv in a year in exceptional circumstances.
In order to make Table 4 complete and correct for all situations, it would have to become so complicated that the whole purpose of the exercise (supposedly aimed at greater simplicity) would be defeated. If values for constraints should in any case ‘be established by a process of generic optimisation’ (paragraph 210), guided by Sections 5.8.4 to 5.8.6, then it is clear that the table is of no practical value to a regulator and could safely be deleted. It seems to be more a retrospective attempt at understanding by ICRP of why the ‘30 or so’ recommended numbers have the values they do than a useful tool for the regulator.
paragraph 205: The first sentence claims that the second band ‘applies in circumstances where individuals receive direct benefits from an exposure situation but not necessarily from the exposure or the source of the exposure, itself.’ In the last sentence it says that ‘In the event of an accident, countermeasures such as sheltering and iodine prophylaxis would fall within this band.’ Then clarification is needed as to what are the benefits from an accident.
paragraph 206: Similar comment to the one above: what are the benefits from an extreme situation – ‘Constraints could also be set in this range in circumstances where benefits from the exposure situation are commensurately high.’
paragraph 213: Suggested modification for the first bullet:
• ‘For rescue operations involving the prevention of serious injury or the development of catastrophic conditions, every effort should be made to avoid serious tissue injuries by keeping doses below about 1000 mSv and, ideally, to avoid other tissue injuries by keeping doses below 100 mSv, the Commission's maximum value for a constraint.’
Making an effort to keep the dose below 1 Sv is desirable in any circumstances.
paragraph 214: This appears to require that all workers everywhere should be subject to regulatory control for radiation exposure. If there is a point to paragraph 214, it needs to be made clearer.
paragraph 217: The 2006 draft recommends continuation of the guidance on dose constraints contained in Publication 77 for waste management. The wording in Publication 77 is: ‘To allow for exposures to multiple sources, the maximum value of the constraint used in the optimisation of protection for a single source should be less than 1 mSv in a year. A value of no more than about 0.3 mSv in a year would be appropriate’. The wording in ICRP77 is not as strong as in paragraph 217. The text should clarify that this value, and the lower value of 0.1 mSv in a year for some cases of prolonged exposure, have been recommended for radioactive waste management and should not be assumed to be automatically applicable in other circumstances. If an impression is created that dose constraints for members of the public should always be 0.3 mSv/y (or less), this could lead to an unintended ‘ratcheting down’ of restrictions on dose that may not be consistent with the principle of optimization of protection. (Some IAEA professionals believe that the ICRP should not recommend any numerical values for dose constraints for the public, other than the requirement to be below the dose limit.)
paragraph 220: As with paragraph 201 (see above), this seems to suggest that in some circumstances a constraint is not a constraint, and it illustrates the difficulty one gets into when attempting to replace action levels with dose constraints.
paragraph 221: In this important paragraph on optimization, costs of protection are not mentioned at all. Cost-benefit or detriment-benefit issues should not be totally ignored.
paragraph 226: This paragraph could imply a fundamentally new situation of having to optimize below the ‘entry level’ into the system of radiological protection. This would have far-reaching implications and brings the whole philosophy of regulatory control into question. How can an entry level for regulatory purposes be reconciled with a requirement to apply regulations below that level?
paragraph 230: This paragraph is not relevant to the subject of 5.8.7 (Application of optimization and constraints).
paragraph 231: From the context one can guess that this paragraph is about collective dose. It would be useful to specify that. Otherwise, the statement ‘The Commission is of the opinion that in the decision-making process, more weight could be given to moderate and high doses…’ becomes trivial and unnecessary. However, if it is about collective dose, then this idea is in contradiction with a strict presumption of LNT as confirmed in Section 3 for radiation protection purposes, and therefore needs further explanation.
paragraph 231: ‘The Commission does not intend to give detailed guidance on such weighting, but rather stresses the importance of demonstrating in a transparent manner how any weighting has been carried out.’ Who will make such recommendations if not the Commission? Relevant guidance could be developed in a separate ICRP document.
paragraph 240: ‘Dose limits do not apply in situations where the exposed individual is engaged in life saving actions or is attempting to prevent a catastrophic situation.’ Not only then: they are not applicable in emergencies and existing situations either.
paragraph 252: This seems to equate a diagnostic reference level to a dose constraint, while at the same time saying that constraints are not used for individual patient doses. This needs clarification.
paragraph 269: This introduces the term ‘medico-legal exposures’. This invented term is not appropriate for ICRP: ‘deliberate non-medical exposure’ could be better. In addition, contrary to previous guidance, the practice is not deprecated. Indeed, higher dose constraints are set: this is peculiar and requires explanation.
paragraph 280: The statement that ‘principles for exclusion and exemption of natural sources are that the individual risk from the source or practice is insignificant, radiological protection is optimised or that the sources are inherently safe and the practice is justifiable’ requires clarification, as it mixes up the concepts of exclusion and exemption. Further, the criteria given cover only two of the bases for exemption. The other basis, namely that regulatory control is unwarranted, irrespective of whether the dose is trivial (see paragraph 46), has been ignored, and yet this is the basis for exemption applicable to natural sources.
paragraph 280: ‘In many cases it will be obvious that action to reduce exposures is not warranted. This conclusion will often be intuitive.’ Suggest replacing the word ‘intuitive’ with the expression ‘based on common sense’.
paragraph 286: Suggest: ‘The overall contribution of 40K is substantial but is fairly constant and is limited by the body’s content of potassium and not by the amount of potassium in the diet.’ All the consumed potassium is first absorbed in GIT and then the extra amount excreted quickly. It’s not an uptake issue. The next sentence (in 286) is incomplete.
paragraph 291: The statement that ‘the distinction between ‘natural’ and ‘man-made’ or ‘artificial’ radiation exposure has proved to be peculiar and unconstructive’ rather conflicts with the fact that the 2006 draft discusses natural sources separately and at some length.
paragraph 294: Care needs to be exercised over the use of exclusion and exemption in the context of natural radiation exposure. These are regulatory concepts. In particular, the use of an exclusion level of 40 Bq/m3, the global mean indoor radon concentration, is unhelpful. The BSS and other safety standards do not specify an exclusion level of this kind for radon. Radon concentrations above the global average will, in a very large proportion of cases, be effectively uncontrollable. Consideration should be given to adopting an analogous approach to that used for naturally-occurring radionuclides in materials, combining risk considerations with observed values towards the upper end of the global distribution in natural circumstances.
paragraph 295: It is not clear whether this paragraph has anything to do with natural sources.
paragraph 298: This paragraph states that the 2006 draft broadly continues the policy set out in ICRP65 for indoor radon and that ICRP has already issued specific constraints for radon at home and at work. This is wrong on both counts, since the draft recommendations appear to suggest an about-turn in protection policy, and the ICRP65 recommendations are for action levels, not constraints. By converting action levels into dose constraints, the whole system for radiation protection for radon would be turned on its head, since an action level is an entry level into the system of radiation protection, whereas a dose constraint is effectively the upper end of acceptable exposure under the system of radiation protection. The IAEA professionals’ previous comments (on the 2005 draft recommendations) cautioned against this fundamental shift but appear to have been ignored. A similar contradiction occurs in paragraph 279, where on one line the draft says: ‘action levels are effectively constraints’ and on another: ‘in contrast to action levels below which no action is required, the process of optimisation and constraints do (sic) not use any predetermined end point below which no action is warranted to reduce the dose further’. Yet another problem in the same paragraph is the description of action levels as ‘levels of aspiration’. This may be so in the case of radon exposure in dwellings, but not in the workplace.
paragraph 301: Since there is already an effective international consensus to adopt an action level for radon in workplaces of 1000 Bq/m3 (or less) and an action level for radon in dwellings of 400 Bq/m3 (or less), it is unlikely that the higher values in Table 6 will have any bearing upon regulations in most countries.
paragraph 303: The meaning in this paragraph is not entirely clear. It seems to be saying that for some radon exposure situations such as mines, the constraint is not a constraint at all, but can revert back to an action level. The reasoning behind this apparent contradiction is that radon exposure is ‘merged with other exposures to ionizing radiation’. This is not the reason at all – radon exposures are always measured and recorded separately from dust and gamma exposure. The real reason for using an action level rather than a constraint is that in workplaces such as mines it is sometimes impossible to reduce radon concentrations (through intervention) to below the action level (such as 1000 Bq/m3, corresponding to 6mSv/y) by any reasonable means, and that higher radon levels have to be tolerated and, accordingly, controlled in terms of the principles for practices (where the dose limit of 20mSv/y [or 50mSv in a single year] applies). This is a fundamental part of the ICRP65/75 recommendations, but has been ignored in the 2006 draft recommendations.
paragraph 304: The statement that: ‘for protection against thoron, it is usually sufficient to control the intake of the decay product, lead-212, which has a half-life of 10.6 hours. The current conversion convention suggested in Publication 65 … is not applicable’ is not helpful on its own; it should be further developed.
paragraph 315: Add: ‘g) effectiveness of protective actions.’
Section 8.5: This deals with exposure arising from actions with malicious intent and should either be deleted or revised to discuss the response to all radiological emergencies. This is needed to make it clear that emergency arrangements should be put in place that are appropriate for any radiological emergency regardless of the cause.
paragraph 332: Not all the accidents referred to here occurred in radiotherapy. The Vietnam accident was not a radiotherapy accident. The Thailand accident involved a radiotherapy source, but was not a radiotherapy accident.
Section 9: This section mentions some of the items needed for development of an adequate emergency response capability. However, the discussion does not cover all of the issues that should be considered in order to develop an adequate response capability. In addition, in some cases, the material is not consistent with lessons learned from past emergencies. Therefore, the recommendations not directly related to radiation protection principles (eg: discussion on response organizations) should be removed and the reader directed to the IAEA Safety Requirements GS-R-2, in which these issues are addressed in detail.
Section 9: The clarification that projected dose approaching the threshold for severe deterministic health effects in the most sensitive member of the public (100 mSv to the foetus) always warrants taking protective actions is supported. However, over the past 20 years, many (most?) States in the world have developed emergency response arrangements consistent with the guidance in ICRP60, ICRP63 and derivative publications (eg: the BSS). These arrangements have included criteria built on the concept of ‘averted dose’. The 2006 draft should be revised to clarify and justify the basis for criteria based on projected dose. In particular, there is a need to clarify:
• What revisions are expected to be made to emergency arrangements developed based on ICRP63 or the BSS in order to be consistent with the new recommendations?
• Are States are expected (by ICRP) to replace criteria based on ICRP63 with criteria consistent with those recommended in the 2006 draft?
• What protective actions would be warranted if taking action based on projected dose will result in only a small improvement in the averted dose; in particular, if the projected dose is well below the threshold for deterministic effects for the most sensitive member of the public (100 mSv to the foetus)?
• How can a constraint expressed in terms of effective dose (eg: 100 mSv) be applied in the case of organ exposure (eg: thyroid)?
Section 9: The 2006 draft should recommend that default intervention levels (operational intervention levels) be developed to allow for immediate assessment in the event of an emergency. In addition, it needs to be pointed out that an examination of past emergencies has found that in many cases operational intervention levels developed after the start of an emergency were not consistent with international guidance because they were developed during a period of mistrust and public pressure (during the emergency).
Section 9 and elsewhere: In general, replace ‘emergency plans’ with ‘emergency arrangements’, and consider the following definition of arrangements. This is needed to make it clear that the development of an adequate emergency response capability involves many elements (eg: those listed in the definition below) and much more than ‘plans’ alone.
arrangements (for emergency response) The integrated set of infrastructural elements necessary to provide the capability for performing a specified function or task required in response to a nuclear or radiological emergency. These elements may include authorities and responsibilities, organization, coordination, personnel, plans, procedures, facilities, equipment or training. [GS-R-2]
paragraph 349: Make it clear that a single set of integrated and consistent (in the eyes of the public) protective action recommendations must be provided to the public.
paragraph 359: Revise to note that the IAEA Safety Requirements GS-R-2, cosponsored by 7 international organizations, provides specific advice on the infrastructure needed to develop an adequate emergency response capability.
Section 11.1.1: Add a recommendation that a ‘plain language explanation’ of the protective action recommendations should be developed in advance as part of the preparedness process to allow the decision makers and the public to make an informed decision when considering what actions to take based on radiological criteria. [See IAEA TECDOC-1432]
paragraph 368: The clarification of the distinction between decision-aiding and decision-making is welcomed.
paragraph 385: Section 11.1 goes into too much detail on regulatory systems. In particular, the 2006 draft states that ‘the head of the protection service should have direct access to the senior operating management’. There is no justification for such a specific categorical statement in ICRP Recommendations.
Definitions of terms
In general, replace the term ‘accident’ with ‘emergency’ and consider the following definition:
emergency A non-routine situation or event that necessitates prompt action primarily to mitigate a hazard or adverse consequences for human health and safety, quality of life, property or the environment. This includes situations for which prompt action is warranted to mitigate the effects of a perceived hazard. [GS-R-2]
Replace ‘serious deterministic effects’ with ‘severe deterministic effects’. This is a better term and consistent with the definition of deterministic effects in the 2006 draft glossary.
Several important terms are missing from the Glossary, such as: action level, intervention, justification, limit, optimization.
The terms ‘licensee’, ‘operator’ and ‘operating organization’ are used interchangeably throughout the draft recommendations. It is suggested that only one of these terms (suitably defined) should be used, e.g.: operator.