The scope of radiological protection

Draft document: The scope of radiological protection
Submitted by Vincent Holahan, US Nuclear Regulatory Commission
Commenting on behalf of the organisation

The staff of the U.S. Nuclear Regulatory Commission (NRC) would like to thank the Main Commission of the International Commission on Radiological Protection (ICRP) for the opportunity to provide comments on the draft document on scope of radiological protection. The opportunity to submit and review other stakeholder comments on Commission documents is greatly appreciated. The NRC was established to regulate the civilian commercial, industrial, academic, and medical uses of nuclear materials to enable our nation to use radioactive materials for beneficial civilian purposes while ensuring that public health and safety, common defense and security, and the environment are protected. We believe this mission is consistent with the aim and goals of the ICRP. With this in mind, the NRC has reviewed the draft document and is providing the following general and specific comments for consideration by the Main Commission. The Scope of Radiological Protection Regulations General Comments: 1. The draft report is a complex, difficult to interpret, and in some places confusing discussion of how regulatory controls might, or might not, be applied. It may not contribute significantly to the knowledge base of national regulatory authorities. The regulatory authorities of a country that has a developed radiation protection program, such as the United States, would not receive significant benefit from this draft report. Unfortunately, the regulatory authorities from countries with a lesser developed regulatory program may not find this draft report to be a clear or useful reference. The ICRP Commission observes in paragraph 119 that “regulatory concepts and terminology are difficult enough without making them unnecessarily tortuous and complex.” This draft does little to reduce the complexity. In fact, the extensive use of Latin phrases and phrases like “exemption within the system” will not promote a simplified system of radiological protection. It is suggested that terms used in the next draft recommendations and this document be harmonized. 2. The draft report attempts to describe a variety of topics that share the common attribute of describing when regulatory control will, or will not, be exercised over an exposure. These topics do not share many other attributes, and the resulting variety of approaches and rationale only serve to illustrate how complex and difficult it is to create a coherent regulatory regime. For example, while pragmatically understandable, it is difficult to explain why regulatory controls have wide discrepancies in the degree of expected radiological protection. The report seems to take as a premise that natural materials will be seen by people as being different, and therefore treated differently. As another example, liquid or gas releases are described as authorized discharges, but solid materials are treated as exemptions or clearance. 3. Much of the numerical material is taken from work of the International Atomic Energy Agency (IAEA), some of which the IAEA is considering revising (e.g., BSS). While this material has broad international consensus within the context of considering relatively large quantities of bulk materials, it does not resolve some important issues. For example, the discontinuity of transportation levels with exemption or exclusion levels is not a desirable position for regulatory organizations. Yet, the draft report seems to state that these different levels exist, and therefore are appropriate. From the standpoint of constructing a coherent, consistent, and predictable regulatory regime, such a discontinuity may not be appropriate. A second example is that the US currently exercises control over quantities of materials at considerably lower levels than some of the values presented for naturally occurring radioactive materials. US drinking water standards are up to 5 times more restrictive than those proposed in this draft for several radionuclides. US residential radon levels should not exceed 148 Bq per cubic meter, a value greater than that proposed by the ICRP Commission. 4. We understand that the ICRP Recommendations will move to clearly identify a consistent approach of establishing constraints, and optimization, for any type of exposure situation. It is not obvious how the various numerical and philosophical statements in this draft report fit within this unified approach to radiation protection. For example, the draft report describes the possibility of "exemption" from requirements to intervene in an existing or emergency situation. This discussion is very confusing, and does not seem to be consistent with our understanding of establishing a constraint, optimization of exposures, and thus determining if some actions to reduce the exposure will be taken. Even within the discussion of exemption from intervention, the text is confusing in that it suggests on the one hand that a 1 mSv dose could be considered as a lower bound for selection of action levels, and then notes that additional efforts to reduce exposure if this is possible for a dominant component. Specific Comments: 1. Abstract, para 5, sentence 1: delete. Food stuffs containing radionuclides in activity concentrations less than the Codex Alimentarious Commission and drinking water containing radionuclides in activity concentrations smaller than the those specified by the World Health Organization should not be automatically exempt. The Codex values are for consumption of foodstuffs and drinking water during the first 12 months following a nuclear accident where release of radioactive material has contaminated foodstuff. The WHO values are assuming a time period after the first 12 months of a nuclear accident. Long term exposure assessment presume a mixing of contaminated foodstuff with noncontaminated materials which will result in a lower annual exposure in subsequent years. The WHO values assume an annual exposure of 0.1 mSv per year, although some of the radionuclides cited may be twice this value (e.g. strontium-90). These situations should not be automatically exempt, rather considered on a case-by-case situation. 2. Executive Summary, para c, last sentence: delete. Too arrogant. 3. Executive Summary, para j: delete. See comment #1. 4. Foot note 5: delete. Unnecessary. 5. Para 8: Comment. The discussion of trifles and triviality should be avoided. What the Commission may consider a trifle is not necessarily shared by many stakeholders. U.S. metal recyclers likely will not accept any recycled metals for processing because of the perception that consumers want clean or virgin metals and will not accept metals containing residual amounts of radioactive material, regardless of the amount. 6. Para 13: Comment. While the Commission may believe that all exposures and sources should not be considered within the scope of radiological protection, this belief is not consistent with projections of latent cancer deaths attributable to the uncontrolled release of radioactive material from nuclear power plants. For example, the WHO estimates there will be 7,000 additional cancer deaths between 1986 and 2065 among 570 million residents of Europe attributable to the 1986 Chernobyl accident. This is in addition to 9,000 cancer death predicted for the most heavily exposed residents and emergency responders/ liquidators residing in Belarus, Ukraine and the Russian Federation. Furthermore, an average occupational exposure of 19 mSv among nuclear workers may be responsible for 1 to 2 percent of all cancer deaths(BEIR VII). 7. Para 21, bullet 3: Reword to “unplanned/unscheduled exposure situations, which are the result of unplanned, unexpected, or emergency circumstances such as accidents. Reason - unplanned releases from a waste discharge line into underground water, on-site, which results in radionuclide levels exceeding drinking water standards is an accidents, but not necessarily an emergency exposure situation. 8. Para 21, last sentence: anticipated accident should read “unanticipated accident 9. Para 33, last sentence: reword to ”public authorities have not considered it ‘amenable’ or ‘optimum’ to move these cities to lower altitudes in order to reduce the cosmic exposure of the residents.” 10. Para 50: It is unclear how the Commission proposes to use the concept of collective dose. This paragraph cites an IAEA reference on how collective dose can be used. Yet, paragraph 200 of the draft 2005 ICRP Recommendations states that collective dose is not to be used on its own in making decisions because it may aggregate information excessively. The use of collective dose in this document should be consistent with the next set of Commission recommendations on radiological protection. 11. Para 60: Delete. The Commission, in general, has not considered medical practice in its discussion of the scope of radiological protection except for the authorized discharge or release of patients with sealed or unsealed radionuclides. Consequently, this paragraph should be deleted and further discussion deferred until another medical document is prepared. At a minimum, comparing medically authorized discharges with annual releases from nuclear power plants is inappropriate. The radionuclides released, potential exposure pathways, and activities released are not similar. If, however, the Commission prefers to retain this discussion, additional information is needed. For example, the Commission encourages international organizations to revisit the issue of discharging patient. Yet, no discussion is provided concerning the benefits, both financially and emotionally, associated with discharging patients. 12. Para 74, line 10: “prove” not “probe” 13. Section 6.1, para 80, line 11: reword to “adventitious (i.e., incidental to the use to which the material is being put) ionizing radiation is not of very low energy, but arise at relatively...” 14. Para 87, line 3: reword as “flying time or flight altitude and rostering of exposed people.” Flight altitude, particularly on trans-Atlantic flights, could be reduced from 40,000 ft to 30,000 ft thus reducing cosmic ray exposure to both passengers and crew, but increasing jet fuel expenditures. 15. Para 87, line 7: Is there a citation to support pregnant business flyers being reassigned to duties that do not require flying? Similarly, how is the flying time of frequent flyers the subject of control? 16. Para 90, sentence 2: Delete. It is unclear (1) why normal operations of nuclear facilities is being used as a baseline for comparison and (2) what aspect of operations is being used (i.e., occupational exposure, on-site exposures to members of the public from effluent releases). 17. Para 97, sentence 2: Delete “detrital”. Reason - plain language. 16. Para 100, last sentence: Delete. Reason - plain language. How many non-geologists appreciate the terms shine-bottom or travertine? 18. Para 114, line 12: reword “interalia” (lat. Among other things). How does an international action level serve as a harmonized monitoring and record-keeping system? 19. Para 116, line 1: reword “Produce” to “Products” or “Commodities”. Produce often refers to farm products (fruits and vegetables), but not building materials. 20. Para 121: Add the following “These levels are designed to be applied only to radionuclides contaminating food and traded internationally following an accident and remain applicable for one year following a nuclear accident, and are based on an intervention exemption level of around 1 mSv in a year. For example, if food containing 90-strontium is consumed for one year at the Codex guideline levels (100 Bq per kilogram), the mean annual internal dose will be 0.2 mSv for adults and 0.5 mSv for infants. Consumption of food containing 137-cesium for one year at the Codex guideline levels (1,000 Bq per kilogram) results in mean annual internal doses of 0.4 mSv to infants and 0.7 mSv to adults. 21. Para 122: Add the following after sentence 1 “The guidelines are based on a recommended reference dose level of the committed effective dose, equal to 0.1 mSv for 1 year’s consumption of drinking water. Some of the guidance levels, however, may exceed the target committed effective dose (e.g., 90-strontium, 0.2 mSv per year). 22. Para 123, line 6: The Commission views 10 Bq per kg for beta and gamma emitting radionuclides to be unamenable to control and thus establish de facto exclusion levels of activity or radionuclide concentration in material. Yet, these values in drinking water yield annual committed effective doses of 0.2 mSv, 0.16 mSv, and 0.10 mSv, for 90-strontium, 131-iodine, and 137-cesium, respectively for adults. Is this really the Commission’s intention? The recommended guidance levels for these radionuclides greatly exceeds the U.S. drinking water standards. 23. Para 126, line 10: reword “produce” to “products” or “commodities”. See comment #18. 24. Para 132, sentences 2-5 (lines 4-15): delete. This discussion does not improve the text of the document. 25. Para 134, bullet 3: add “non-ingestable” before substances. The recommended activity concentrations in drinking water greatly exceed U.S. regulatory limits. 26. Para 140: Delete all. The Codex guidelines are for use during the first year after a radiological accident. The draft guidelines are reduced up to three orders of magnitude for long term exposure. The WHO guidelines for drinking water are up to 5 -times higher than current U.S. drinking water standards. 27. Para 148, sentence 1: Delete. Unnecessarily complicated and of very limited value.