Recommendations

GENERAL COMMENTS 1. The document is not a “self-sustaining” document. For those who deal with public exposure in all types, at least 6 documents are to be consulted to apply the recommendations: ICRP Publications 63, 65, 82, 101, and on the new documents on the reference individual, on the scope of radiological protection, and on optimization. For those who deal with medical exposures, ICRP Publications 44, 62, 73, 84, 87, 86, 88, 90, 93, 94, 95, 97, 98 are to be consulted and every replacement in referenced documents lead to additional addendum to this publication. 2. Some of these referenced documents have aspects that are not compatible with the current draft, mainly regarding the new basic approaches to exposure situations, reference levels vs. constraints, and so on. At least, the basic concepts and basic numerical recommendations from such documents should be included on the current draft. 3. The idea of joining public and occupational exposures is not well addressed; there are differences related to age, risk, dose assessment, uncertainties and controllability that should be discussed in the document. 4. While some aspects are repetitive in the document, others are still not clear enough. The recommendations are vague in many aspects. It will be difficult to derive regulations and verification of compliance and, what is very important in many situations, particularly those involving public exposure, to demonstrate that international recommendations are being followed, as the international recommendations are not clear or precise enough. It will also be difficult to reach consensus among countries with such broad approaches. Also, the “do the best you can” is not enough, nor for the regulatory bodies or decision makers, nor for public reassurance. 5. It is not clear in the proposal on the types of exposure situations where to address contaminated sites (i.e. existing radiation fields with no current exposure situation, but possible to occur in the future); the separation of such areas according to their former history as proposed is also confuse. It is not clear why, from the point of view of radiological protection, a previously abandoned site is to be dealt under a different approach from that of a site to be released. 6. The new definition of emergency is also confusing. It is not clear if malevolent acts are not supposed to lead to emergency situations. Also it should not be used a word that has already a current colloquial meaning to some specific situation. For most people that shall be involved in attending something like a “dirt bomb” it may be difficult to explain that it is not an emergency because it was not consequence of a practice. 7. The new name “planned exposure situations” is welcome. The previous “normal exposure” to describe exposures from practices was not adequate. 8. The text is segmented, according to the type of exposures, the principles of protection, potential exposure, exposure to natural radiation, etc. It would be easier to the reader (and user) to describe the general principles in the beginning of the document and keep the situations of exposures as a whole together. SPECIFIC COMMENTS Chapter 1 - Introduction §17… The dosimetric quantity recommended for radiological protection, effective dose, is also computed by age-and gender-averaging…. Comment: This recommendation need to be more clear as introduces important changes regarding public exposure. It also conflicts with ICRP draft on “Assessing dose of the representative individual for the purpose of radiation protection of the public” that recognizes the need of dealing with at least 3 different age groups. Chapter 2 – The aims and scope of the recommendations §32 …the implementation of the recommendations by users, operators and regulators of radiation sources, public health authorities, and employers, the workforce, and the public at large. Comment: it is not clear in the document how the “public at large” can be directly related to the implementation of ICRP recommendations. §33…the operator may be expected to keep application of the optimization approach under continuous review during the operation of the practice… Comment: the recommendation is interesting but seems not to be realistic, mainly if production costs are involved on improving optimization. The idea of having the operator applying optimization under continuous review includes a lot of subjective aspects; changing procedures in a continuous base will turn difficult to regulatory bodies to verify compliance, particularly for those practices with large number of operators. Anyway, the need to review if there is any operational or environmental change would be relevant. §33... the important message …is that a similar approach is used in optimization, regardless of the type of source or the exposure situation. Comments: the meaning of this sentence is not clear; quite different approaches are to be used, e.g., in medical and public exposure, or in planned vs. existing exposure types. §41...with current technologies, extreme low and trivial levels of radiation and radioactivity are detectable... Comments: although the sentence is correct in a broad sense is may not directly applicable for some exposure situations, such as some planned situations involving natural radioactivity on high background areas, where the question is not upon detection limits but on detection of differences over background levels. § 42 and 45 (§42): Strictly, the term “exemption’ can only apply to personal entities... (§45): certain practices and sources … may be exempted from some requirements… Comments: there is some inconsistency in these two paragraphs. Practices and sources can be “exempted” from the scope of regulations and personal entities dealing only with such practices or sources would be exempted from the legal obligation by the regulatory body. Or exemption applies to all or the text must be reviewed. §45 and §167 Comment: the meaning of “man-made sources” must be made clear in the document; values cited in paragraph 45 apply only to artificial radionuclides. Public exposure, as described on paragraph 167, should include both man-made and man-enhanced sources. Chapter 3- Biological aspects of radiological protection Table 2 and Table 4 Comment: There is a significant difference between risks to the whole population and only to adults (50 % difference on Table 2 values for risk coefficients). Considering that the “average member of a population” is closer to an adult than to a child, these differences are probably higher if children are considered as a separate group. Besides the risks, dose conversion coefficients available up to now are also different for adults and children, and differences may be up to a factor of 10, for bone-seeker alpha emitters. Even so, age and gender averaged effective doses are recommended to be used and the same table for constraints is also to be applied. Is that correct? Anyway, this needs to be better explained and be made clear on the text. Chapter 4 – Dosimetric quantities §88…and tissue reactions (sometimes also, but less precisely, termed deterministic effects)… Comments: the term deterministic is used throughout the document. §97 and 98 Comment: these paragraphs discuss several situations where averaging doses may not be adequate but include no recommendation on what to use. §101 Comment: there should be a description, close to the table, on the scope of the use and limitations of values on Table 3, including the last 2 sentences of paragraph 103. Item 4.3.4 Comment (1): is it adequate to use the same set of wT values, derived from exposed populations to patients with different health status? Comment (2): gender and age averaging are not adequate to medical exposures §118 - 120 ... ……the equivalent dose to the tissues of remainder of the male and female…are computed as and Comment: or HRTM,F should be divided by 13 or the value of wT on Table 4 for the remainder tissues should be reviewed. Item 4.5.5 Comment 1: The title, Medical exposure of patients, may lead to misunderstandings, as Chapter 6 includes the exposure of comforters and families under this title. The exposure of these groups is to be treated under the scope of medical exposure (certainly it is better than in public exposure, as in BSS) but is not a “medical exposure of patients” Comment 2: effective dose should not be used for medical exposure §137 Comments: Assessments of intakes are very different than assessments of external exposure. Intakes of radionuclides in medical exposures may lead to absorbed doses in tissues that are not imaged due to the patient metabolism. This does not occur in external exposures because there are techniques to restrict exposures to the imaged tissues. §138 Comment: Considering that there is consensus that effective dose is very problematic and lead to misinterpretation, it is recommended not to use this quantity for medical exposures of patients. §139 Comment (1): Include “except for medical exposures” on the first sentence Comment (2): more guidance is need on assessing doses after accidents §151 Comment: the paragraph does not recommend anything and should be removed §153 Comment: dose conversion coefficients will need to be recalculated. Chapter 5 – The System of Radiological Protection of Humans §160 ...if radioactive materials are released from an installation to the environment,the installation as a whole may be regarded as a source; if they are already dispersed in the environment, the portion of them to which people are exposed may be considered a source. Comment(1): this should be made clearer as to define when and which constraints are to be applied. Also it should consider that while effluents are “source-related”, environmental pathways includes “individual-related” aspects. §162 … Planned situations are everyday situations involving the planned operation of sources including decommissioning, disposal of radioactive waste and rehabilitation of the previously occupied land. Practices in operation are planned exposure situations. Comments: the term “previously occupied land” must be defined. It seems not to include “past practices that were operated outside the Commission’s recommendations” as these are included in “existing exposure situations” and it is not clear if it includes evacuated areas, for example. … Emergency situations are unexpected situations that occur during the operation of a practice, requiring urgent action. Emergency situations may arise from practices. Comments: This definition is ambiguous. The first sentence limits the scope of emergency situations to the operation of practices, while the second sentence states the emergencies “may” arise from practices. Orphan sources events and terrorist acts are not included in “emergency situations”? Are to be included in “existing exposure situations” as residues from practices that were operated outside the Commission’s recommendation? These situation, if occur, are not, certainly, potential exposures. …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. Comment: this type of exposure does not include areas contaminated from accidents, after emergency? If so, this should be included; if not; to what type of exposure it is to be associated should be defined. Comment: what is a potential exposure? It is neither a type nor a category – something about it should be described here. Item 5.3.1 Comment: It is not clear in the text if potential exposure of workers is to be considered as occupational exposure as “being the responsibility of the operating management”; according to the definition, air crew is to be considered occupational exposure; Comment: Responsibility of licensees and employers should be addressed more deeply. Both have responsibilities but not the same responsibility. Something should be said about that as employers are just to be responsible by what they know; in many situations they are not, or have not, expertise in radiological protection. Item 5.3.2 Comment (1): good approach to have “public exposure” including background radiation. But the limits to the public must take that into account (see Comment on Tables 4 and 5. Comment (2): this is a new approach; usually the public is not considered as an individual but as groups of the general population and not direct linked to the source. The inclusion of fetus of pregnant workers or patients is confuse as, although the limits for members of the general public may be applicable to the exposure situation of these “individuals”, decisions on such exposure are to be dealt within the scope of occupational or medical practices. Comment (3): again it is necessary to define “man-made sources”; it is not clear if NORMs are or not included. If yes, paragraph 45 must be reviewed; if not, it needs some consideration here. §169 ...workers (informed individuals)... Comment: if workers are to be “informed individuals” the responsibility for this information should be described in the document. §171…Other workers, such as administrative and support staff, are more similar to the generic public and are treated as such Comment: They are not as generic public because the licensee has responsibilities with their exposure, may control their habits, such as access, supervision, evacuation at an accidental event, among others, that are not under the control of the licensees regarding public exposure. Limits and constraints used for public exposure may be used for radiological protection purposes but they must not be considered as a “boundary” between occupationally exposed workers and the public. Aspects related to doses to workers are well addressed in paragraph 395. §176 Comment: if the guidance provided by Publication ICRP 101 is to be followed, that document will have to be updated: it still uses nomenclatures such as “normal exposure” to mean exposure due to practices, stresses the need for age specific dose assessments. Item 5.5 Comment: add an item on medical exposure of children §179 Comment: There is no recommendation and reference “forthcoming ICRP report” may be not available on time. §186… Dose limits do not apply to medical exposure of patients, emergency situations, or to existing situations. Comment: according to item 4.3, dose limits are also not to be applied to the operational control of practices §187…For occupational exposure, dose limits apply to those situations which are determined by the regulator. Comment: This is not a guidance or a recommendation – it means that each regulator is supposed to create its own rules? Although some flexibility is foreseen, ICRP is expected to give guidance to regulators on what it is supposed to regulate. Giving number for constraints and limits, irrespectively from its possible scope of application makes no sense. More guidance is needed Item 5.8 …Text box Comment: there is a good definition for stakeholder in other ICRP documents §190 Comment: The society vs. individual approach should be more discussed; if benefits are to be addressed by collective doses, for a society it will mean that the focus of radiological protection are adults. There may be several situations where critical exposed groups may be identified, related to emergency situations (air-grass-milk-children, for example). § 191 Comment: The justification lies always with the profession societies, not with the government. Even the wrong use of medical practice is judge by medical professional societies. The levels of justification are not totally in agreement to its current use and understanding in medical practice §207 Table 4 should present the constraints all related to the same quantity, incremental individual doses or total dose, or, at least, have a foot note or a comment on the 100 mSv dose constraint. §211… It will usually be appropriate for such dose constraints to be fixed at the national or local level. Comment: need more guidance 5.8.5. Dose constrains in medical exposure of patients § 215 Comment: Insert “For previously justified medical exposures”, some exposures have to be incurred in the care and support of patients. §219…It is the responsibility of national authorities to select this constraint, which should not exceed 100 mSv per year and typically should not exceed around 20 mSv per year. Comment: text is confusing; maybe the sentence should be inverted § 224...This means that the responsible agencies should periodically ask whether all that is reasonable has been done to reduce doses. The effort that is expended in answering this question in the case of an operating practice may well be more than, say, in the case of an existing exposure situation involving natural activity where the answer may be intuitively obvious. Comment: considering the present effort and difficulty to reach international consensus on dealing with NORMs, is does not seems to so intuitive for existing exposure situation involving natural activity. § 228 Comment: these aspects are important and should be more discussed; it should also be discussed aspected related to specific groups of population with higher risk related to specific exposure situations, such as children after accidents, due to their needs on a milk diet. § 229 Comment: This is an excellent remark but collective doses may not be possible to be estimated; some guidance is needed on how to deal with the possibility of exposure when no probability can be reasonably assessed. More guidance on optimization process is needed, e.g. for non-occupied contaminated sites as there is no reasonable way to estimate collective doses. § 231 …The Commission is of the opinion that in the decision-making process, more weight could be given to moderate and high doses and to doses received in the near future. This is because of the increasing uncertainty of the relevance of very low doses and doses received in the remote future. 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. Comment: Some guidance is need. § 233…An open dialogue must be established between the authority and the operating management, and the success of the optimization process will depend strongly on the quality of this dialogue. Comments: radiological protection can not depend on the quality of dialogs. Even considering only practices, and planned exposures, it is hard to believe a regulatory body with open dialogs with thousands of operator and users; after an accident, it is almost impossible to relay on “dialogs” with some basic clear rules, as there are groups with different interests and different levels of knowledge on radiological protection. With no clear rules, it will hardly exist a quality of dialog when considering exposures above normal background levels or higher than constraints for public exposure. Table 4 This table needs to be revised and clarified in many aspects. As it is, there includes several questions such as: - what is a “single dominant source”? - must be clear when the value refers to a incremental dose or a total dose as the table is referred to a “single dominant source” - the constraint value of 100 mSv is really adequate for public exposure? Paragraph 78 says: “…there is a true dose-threshold of around 100 mGy for the induction of malformation…”; some security margin should exist as in any group of a normal population there will always have embryos and fetus. - assessment of individual doses is to be taken when evacuating a population based on projected doses? §235 …A tolerable exposure is one that can reasonably be tolerated, although there may be room for optimization of protection leading to lower exposures. An acceptable exposure is one that can be accepted without further improvement, i.e., protection has been optimized. In this framework, the dose limit represents a selected boundary in the region between unacceptable and tolerable for the situation to which the dose limit applies, namely for the control of sources in planned exposure situations. The dose constraint in each band represents the level of dose where action is almost always warranted. Comment: this paragraph needs to be revised Table 5…Title: Recommended dose limits Comment: Suggestion for title: Recommended dose limit for incremental doses in planned exposure situations Chapter 6 – Medical exposure of patients § 244 … but should be recognized that some exposures have to be incurred in the care and support of patients. Members of the public may also be exposed in the course of caring for patients at home. Comment: When members of the public may be exposed due to justified medical exposures of patients, the assessment of their exposures should consider the necessities of patients care. In this condition, the exposures of members of the public are considered as “medical exposures”. It may be necessary to accept exposures higher than 1 mSv or even 5 mSv, but all doses may be previously estimated. § 246 … the physicians involved in the processes that irradiate patients should always be trained in the principles of radiological protection. Comment: the formal education, qualification, certification as well as re-certification of the physicians that request and deliver exposures to patients should include knowledge of radiological protection, since such exposures are not limited by any regulatory process but are controlled by these physicians. The regulatory agencies may consider the appropriateness of certification process of physician’s qualification in agreement with professional societies. The same is applicable to the biomedical staff. § 247 Comment: Paragraph 191 cites 3 levels of justification and here only two. §248 Comment: Replace “procedures” by ”protocols”. §249 Comment: Replace “procedures” by “protocols”. §250 Comment: Replace “procedures” by ”protocols”. 6.2.1. Diagnostic reference levels General comments: Six references are cited in six paragraphs. It is too much. Diagnostic reference levels should be established by medical societies after national surveys on image quality and doses assessments. §256 and §258: Comment: Radiotherapy does not have “diagnostic” reference level. So this should be moved this paragraph of item 6.2 §257 Comment: may be removed because there are three references and no recommendation. §258 Comment: reference cited is old, needs to be updated, and should not be used as reference for these new recommendations. Item 6.3 Comment: The exposure of pregnant woman seems to be placed correctly under the scope of medical exposure; however, it conflicts with Item 5.3.2 that includes these exposures as public exposures. §Item 6.4 Comment: good to see this under the scope of medical exposure. § 276 Comment: More guidance is need Chapter 7 – Exposure to natural sources General comment (1): Natural origin source or natural source of man-made origin. It is not clear: Are natural source concerning only with naturally-occurring radiation? Does it encompass TENORM? By reading paragraph (277) it seems that it is only about natural radiation of natural origin. In the TENORM case, the radiation is of natural origin, but the source is not a naturally-occurring one, since it was introduced by man activities (man-made source?). It should be an initial paragraph explaining the scope of the Exposure to Natural Source section. May be a rewritten paragraph (282) should begin the section. General comment (2): Several references are cited but a summary on recommended values to be used as constraint would help. While ICRP 82 recommends a value of 0.1 mSv per year as a constraint for long-lived radionuclides in the environment (paragraph 217), exemption for natural radionuclides adopt a different approach and values may be conflicting. §279 Comment: Fourth line: section 8.4 is about security issues, there is nothing to do with Rn, as it is referred on the text. The text about the need of optimization and action levels recommended by ICRP is not clear! Explanation of optimization concept should not be mentioned on it, but referred to the optimization section. §280…Actions to reduce exposures is not warranted and the conclusion will often be intuitive. Comment: Will be often intuitive? It should be taken out §285 …Indoor exposure are… Comment: this sentence should be taken out of this paragraph and the information included in the paragraph (287) on Radon. §286 Comment: the sentence “Intakes of radionuclides in the thorium and uranium decay series” is incomplete. §287…Within a country much larger variations can occur with some homes over one hundred times the average level making radon the most commonly variable source of natural exposure. Comment: All source of natural radiation present a wide range of values. For example, Ra content in water may vary over 3 orders of magnitude. The sentence must be reviewed. §294… Examples of sources which should be excluded are cosmic rays at ground level, 40K in the human body and unmodified concentrations of naturally occurring radionuclides in most materials, except food stuffs, drinking water and animal feed, below 1000Bq/kg for the heads of uranium and thorium series and 10,000 Bq/kg for 40K. Comment: This description of exemption for natural radionuclides is somewhat different from previously recommendations and need some more explanation. Are these values not supposed to be valid for modified materials? What to use then? … Due to the wide variations in residential radon concentrations between regions, exclusion levels should be set 40 Bqm-3, i.e. the global mean indoor radon concentration The Commission recommends that such sources are excluded from the radiation protection system. Comment: This value is close to worldwide average. Using this exclusion would mean that half the world would be included in the scope radiological protection; other ICRP documents recommend an exemption value of 200 Bqm-3, what is much more reasonable as a level of concern for radiological protection. § 295. Comment: The text is confusing: it is not clear what is a natural “sealed” source; also, the sentence “with a dose rate less than…” should be taken out of the paragraph. § 300... For dwellings this range was a radon concentration of between 600 - 200 Bq m-3, while the corresponding range for workplaces was 1500 - 500 Bq m-3. ... Comment: the range should be described in the correct way, 200 – 600 Bq m-3 and 500 – 1500 Bq m-3. The uses of the highest values of ranges as constraints are welcome. Chapter 8 – Potential Exposure Item 8.5 General comment: malicious intent acts are to be considered under the scope of potential exposure, as much as accidents; but the response to such acts (paragraphs 327 – 330) is not to be dealt within this chapter. Item 8.6 Comment (1): It is not clear why this chapter is under the heading of potential exposure Comment (2): accidents and malicious intent events are under the scope of potential exposure for planning purposes. If they occur, they are to be dealt under the scope of some type of real exposure, either emergency or existing exposures. Chapter 9 – Emergency situations and existing situations Comment: these two exposure situations have been separated from the previous context of intervention and should be discussed on separate chapter or remain together as previously recommendations (excluding radon that is now in a specific section on exposure to natural sources. § 341… The claim for protection is generally stronger when the source of exposure is a technological by-product rather than when it is considered to be of natural origin. Comment: this may be true for countries with large nuclear industry but is not true for most developing countries, mainly those that also have large number of high background areas. Item 9.4 Paragraphs 345 and 346 need to be revised as the information seems to be conflicting. While in paragraph 345 the recommendation goes from the individual to the society, paragraph 346 recommends exactly the opposite order. Chapter 10 – Protection of the environment The chapter was found to be adequate and represents a sound commitment and according with the real situation on current developments regarding this topic Glossary Should be included: Controlled and uncontrolled dose (as referred on paragraph 31) Exiting exposure Planned exposure Emergency exposure Source of radiation (34 and 160) Controllable source (35) Practice (38) Intervention (39). Man-made source. Natural source. Constraint Representative individual (176) Committee for comment on ICRP recommendation draft: Elaine Rochedo, Dejanira Lauria, Nadia Martins, Silvia Velasques, Maria Cristina Lourenço, Claudia Maurício, João Leocádio, José Marcus Godoy