General Comments This is a well thought out, logical, and clearly written document. It represents an evolutionary progression from the previous ICRP documents, rather than a revolutionary departure (which some of us feared might happen). Specific Comments Summary (S4) line 7 – Suggest replacing “as a failure” with “as unsatisfactory, requiring improvement.” This change specifies a remedy that the ICRP draft doesn’t. (S5) last sentence – The term “virtually certain to be justified,” does not provide any useful guidance. Suggest replacing with:” These constraints represent the level of dose above which action to avert exposures and reduce doses is necessary.” (S6) lines 2-3 – This sentence suggests that the natural radiation background produces no adverse health consequences. Suggest modifying to: “This is because it is prudent to assume, for the sake of radiation protection standard setting, that there may be some health detriment associated with low doses, even at or below those associated with natural background radiation sources.” (S6) last sentence – This appears to contradict the statements regarding numerical analyses for optimisation in paragraph (S9) and Chapter 7. (S7) The expectation of the ICRP that national authorities should set lower values for source constraints would be achieved more readily if the ICRP itself recommended (and justified) lower levels than those stated. If this is not intended, then the ICRP should eliminate this paragraph, except for the first sentence. (Table S1) – This table is very confusing as it mixes emergency exposures and those from normal operation and one-time exposures with continuing lifetime exposures. A suggested enhancement is attached as revised Tables S1A and S1B. (S10) – Suggest adding,” including exposed workers” on line 3 after “radiation exposures” to ensure that the role of exposed workers in reducing their exposure is acknowledged. (S11) Suggest revising the paragraph after the first sentence to: “The extent of stakeholder involvement will vary from one situation to another in the decision-making process. Stakeholder involvement can result in increased acceptance of the outcome and is a recommended part of the decision-making process.” (S12 and Table S2) The values in the table make reasonable sense. For example, they would exclude potassium in bananas (0.13 Bq 40K/g) and seawater (0.01 Bq/g) and alpha activity in brazil nuts (0.52 Bq/g) and radium in typical soils (0.03 Bq/g). It might clarify the table if radium-226 were explicitly indicated and if an example of an artificial alpha-emitter (e.g., 239Pu) were given. (S16) second line – Why use the term “radiation incident on the body?” This seems related only to external exposure. Suggest replacing this phrase with “radiation absorbed in the body.” (S18) line 6 – Should other species be protected using the same scientific basis as for humans? It appears that there might be a fundamental difference between human protection and protecting the ecosystem. The latter might allow for the loss of some individuals representing only a small portion of the population. This is consistent with (248). (S19) Is an international agreement on discharges necessary or even technically feasible? Doses from radionuclide discharges into the environment do not always have a direct relationship to the source as do occupational doses. The complexity of the atmospheric and hydrospheric dilution processes and bioaccumulation mechanisms make the relationship between environmental releases and dose to the receptor very dependent on the nature of the environment and highly variable from one location to another location. This presents a major difficulty in standardizing releases and keeping uniform risk goals. The Commission should seriously rethink advocating uniform release levels as opposed to uniform dose constraints. Main Body (18) I agree with the comments on justification and have had long-standing reservations regarding the quantitative cost-benefit concept introduced with the concept of justification in ICRP Publication No. 26. However, to completely relegate “justification” to the authorities omits what may be an important principle of radiation protection. The application of justification to practical radiation protection is through the principle that: All unnecessary radiation exposures should be avoided. This should be explicitly stated. (38) line 5 – Suggest adding “independent of dose rate” after “with no threshold” as this assumption is implicit in radiation protection philosophy and measurements. (81, Table 3) – This Table would be more understandable if the second column were headed “individual organ wT” and the third column were headed “group total.” (93) line 8 – It is hoped that the Commission would include values for both 1 mSv and the 20 mSv occupational dose constraints. (112) last two lines – Although it has been common to write 5 x 10 -2 as 5 %, I believe that this technically incorrect and could be misleading. The fact that values (like the risk factors) are expressed as 0.05 or 5 x 10 -2 does not make them equal to 5 %. Percentages refer to a fraction of some larger quantity. The radiation risk estimates are not fractions of some larger quantity. (136) last sentence -- The expectation of the ICRP that national authorities would set lower values for source constraints would be achieved more readily if the ICRP itself recommended (and justified) lower levels than those stated. If this is not intended, then the ICRP should eliminate this sentence. (139) 1st sentence – This appears to contradict the statements regarding numerical analyses for optimisation in paragraph (S9) and Chapter 7. Suggest: “…cannot always be defined in quantitative terms…” (161) If the comment on 18 is accepted, then it would be useful to insert after “frivolous”: “… (consistent with the application of the justification principle that all unnecessary radiation exposures should be avoided).” (163) last sentence – See comment on 136. (Table 7) – This table suffers from the same faults as Table S1 in the summary – It combines “apples” (one time exposures) and “oranges” (continuing long term exposures (166) p 44, first full sentence – The expectation that source constraints require further optimisation and that this would invariably result in a lower value is incorrect. First of all, the optimisation process may result in a value higher than a constraint already selected. Secondly, some source constraints were originally developed from an optimization analysis – the U.S. Nuclear Regulatory Commission design objectives for U.S. light-water reactor effluents in Appendix I to 10 CFR Part 50 and the EPA Generally Applicable Environmental Radiation Standards for the Uranium Fuel Cycle in 40 CFR Part 190 are examples of this. Suggest replacement by: “ Optimisation should be considered as a necessary part of the process of developing and/or implementing source constraints.” (168) These three categories are not mutually exclusive. Informed individuals can include members of the public. Suggest making four categories, replacing “Informed individuals” with “radiation workers, general workers” and replacing “general individuals” with “members of the general public.” (169) In light of the above comment, this paragraph should be revised: (169a) Workers in “controlled areas” of workplaces fall into two categories: (1) radiation workers and (2) general workers. Radiation workers are those individuals whose job directly involves work in the presence of radiation fields or radiation sources. Radiation workers should receive training including discussion of the risks entailed in this work. Radiation doses to individual radiation workers should be monitored either directly, using personnel dosimeters or personal air samplers, or by monitoring the working area. (169b) “General workers” are persons working near radiation sources but who are not directly involved in the radiation-producing activity. General workers may not be individually monitored nor extensively trained (beyond a general orientation lecture concerning the radiation-related activity). (171 et seq) Although the concept of a critical group is a long-standing concept of the ICRP (see following comment), I think that the ICRP should rethink its application in current situations for the following reasons: (1) The concept was developed to treat situations where there were significant differences in doses among exposed populations, e.g., the dose to the thyroid gland of a one-year-old drinking milk. The concept of effective dose has made these differences in organ doses less important than they were in the past. (2) The composition of the critical group will vary with the exposure pathway. There could be one critical group for atmospheric radioiodine releases, another for liquid effluents and yet a different critical group for direct external doses. (3) Regulatory compliance may entail legal actions. The vague concept of a critical group may be difficult to explain and justify. Regulatory agencies usually require that doses be related to receptor at a specific location either for computer calculations of doses or doses calculated from environmental measurements. (4) The concept of a critical group requires that the group be relatively homogeneous. How is conformance with this requirement defined? I prefer to use the concept of the maximally-exposed individual (MEI) who is defined as the individual who receives the highest dose from all exposure pathways combined (but not the sum of the highest doses for each pathway, because these may not be to the same individual or at the same location). (172) The concept of the critical group goes back (at least) to ICRP Publication 7, “Principles of Environmental Monitoring related to the Handling of Radioactive Materials,” Oxford: Pergamon Press (1965) (15). The guidance in that paragraph concerning selection of the critical group should be repeated here if the Commission disagrees with the previous comment and retains the critical group concept. (180 Table 8) Suggest adding a third column to Table 8 to make the action levels more prominent: Table 8. Recommended Maximum Constraints and Action Levels for Radon-222† Situation Maximum Constraint Bq m-3 Action Level Range Bq m-3 Domestic Dwellings 600 200 – 600 Workplaces 1500 500 – 1500 † Head of Activity Chain (187) last sentence – See comment on S6. (190) line 2 – Suggest adding “and reducing” after “preventing,” since total elimination may not be possible. (191) second sentence – See comment on 166. (193) line 5 – It is not clear what is meant by “individual factors.” Would “protection of the individual” be more appropriate? (196) See comment on S11. (197) Suggest adding at the end: “Where possible, the calculated or measured distribution of doses should be shown. This can be useful information for radiation control planning.” (199) third line from end – suggest “related to” instead of “from.” (200) Suggest replacing last sentence with: “It will be useful to present the available information on the distribution of doses among individuals as well as the collective and maximum individual doses.” (202) I think that “age and gender dependent” doses are unnecessary complications for both occupational and public radiation protection (except for protection of the embryo-fetus). Advocating age-dependent dose and risk factors only appears to be adding sophistication. I note that the Commission appears to believe that age and sex specific tissue weighting factors are unnecessary, as in A18: “(A18) The Commission has made a policy decision that there should only be a single set of wT values that are averaged over both genders and all ages.” If the fundamental parameters of effective dose are age and gender insensitive, why should age and gender dependent doses be advocated? The ICRP should formulate population-weighted intake-to-dose and dose-to-risk factors for a typical member of the worker population and a typical member of the public as suggested in (173). (217) The following should be added to this paragraph: “It also means dispensing with examinations or procedures, such as unnecessary repeated X-rays or diagnostic admission screening exams, conducted primarily to protect the physician or the institution.” A new paragraph should be added, regarding facility design: (217a) Areas in medical and dental treatment facilities where diagnostic or therapeutic X-rays, nuclear medicines, or high-voltage accelerators are used should be specifically designed and adequately shielded to minimize exposure of workers, visiting members of the public or members of the public in adjacent buildings, areas or in the general environment. Beam directions and directional use factors should be chosen to achieve this goal. (228) Suggest: (228) Potential exposures are exposures which may not occur with certainty, but can be predicted to occur with a low, but finite probability. An example of a potential exposure would be a serious accident at a major nuclear facility. It should be recognized that there may be less serious events which are also accidents that can occur with higher frequencies, but these can be classified as anticipated operational occurrences and considered with the exposures from routine operation. It is necessary to control both the frequency of occurrence and the severity of the exposures from potential exposures. There is usually…” (250) The first and last sentences appear to be contradictory. Suggest replacing both (250) and (251) with: (250) The Commission recommends a system to assess doses to representative species that can be a framework to derive regulations, guidance and advice. The underlying aim is to provide a mechanism for protecting the non-human environment that parallels the approaches already in place to protect humans (See Figure 4 and Annex B). Annex A (A2) There should be some explanation accompanying the statement that: “The components of detriment are essentially the same for cancer and hereditary disease…” This is not self-evident. (A8) line 4 – What does “suitably rich” mean in this context? (A8) for clarification, suggest adding: “…because the baseline risk is an explicit factor in the risk calculation.” (A17) Suggest adding to the last bulleted section: “…,particularly the fact that, while radiation-induced genetic effects have been observed in rats, fruit-flies and similar experimental animals, there is no concrete evidence of such effects having occurred in humans.” Annex B (B23) This discussion begs some mention of the inverse relationship between the lethal dose determined for plants and the chromosome volume of the species. See Sparrow, A.H. “Relationship Between Chromosome Volume and Radiation Sensitivity in Plant Cells,” in Cellular Radiation Biology, Baltimore, Maryland: Williams & Wilkins Co.(1965). (B24) Suggest adding: “This is because protecting the individual will establish an upper bound on the radiation detriment to the population.” (B27) See comment on paragraph 250. (B28 and B29) Suggest replacing “the same scientific basis” with “a similar scientific approach.” As noted in B24, the basis for protection might be different (individual vs. population). Table S1A. Recommended Dose Constraints for Limiting Doses from Single Sources for a Limited Time Period Situation Exposed Individual Frequency of Exposure Dose (mSv) Lifetime Dose (Sv) Lifetime Total Risk* A. Emergency Life-Saving or Preventing Serious Injury or Catastrophic Impacts Volunteer, preferably above reproductive age Once in a lifetime 500 500 2.4E-02(a) B. Emergency Situations (Other than A) Worker Once or twice in a lifetime 100 < 200 < 9.8E-03(a) C. Emergency Situations Evacuation and Relocation Members of the General Public Once in a lifetime 100 100 6.5E-02(b) D. Emergency Situations Remedial measures, sheltering, iodine and other chemical prophylaxis Members of the General Public Once in a lifetime 20 20 1.3E-03(b) E. Remedial Actions (food interdiction, indoor radon, persons caring for therapeutic patients) Members of the General Public Limited Period 20 20 1.3E-03(b) * For stochastic effects only (a) Occupational risk factor = 4.9E-02/Sv (b) Public Risk Factor=6.5E-02/Sv Table S1B. Recommended Dose Constraints for Limiting Doses from Single Sources for Recurrent Exposures Situation Exposed Individual Assumed Duration of Exposure Dose (mSv) Maximum Lifetime Dose (mSv) Lifetime Total Risk* Occupational Exposure Radiation Worker (Monitored and Trained) Annually (for 45 years) 20 900 4.4E-02(a) Occupational Exposure Worker (Persons working near radiation sources who are not individually monitored nor directly involved in the radiation-related activity) Annually (for 45 years) 5 225 1.1E-02(a) Temporary Transient Members of the General Public (Persons living near radiation producing activities) Less than 5 years 5 25 1.6E-03(b) Incidental Exposure Members of the General Public (Persons living near nuclear facilities or infrequent visitors) Annually (for 70 years) 1 70 4.6E-03(b) Incidental Exposure (when exposure to multiple sources is likely) Members of the General Public Annually (for 70 years) 0.3 21 1.7E-03(b) Unrestricted Release of Materials Members of the General Public Annually (for 70 years) 0.1 7 4.6E-04(b) Lower Boundary for Control Actions Workers and Members of the General Public Annually (for 70 years maximum) 0.01 0.7 4.6E-05(b) * For stochastic effects only (a)Occupational risk factor = 4.9E-02/Sv (b)Public Risk Factor = 6.5E-02/Sv