|REVIEW COMMENTS ON
THE PROPOSED ICRP GUIDANCE DOCUMENT
“2005 RECOMMENDATIONS OF THE INTERNATIONAL
COMMISSION ON RADIOLOGICAL PROTECTION”
S.Y. Chen, Ph.D.
Argonne National Laboratory
Argonne, IL 60439, USA
1. THE RATIONALE AND SUPPORTING BASIS NEED TO BE STRENGTHENED. As significant as this document is purported to be, its rationale and supporting basis need to be strengthened in the following areas:
• Given that a few of the major supporting technical documents are yet to be finalized, I recommend that the publication of this guidance document be postponed until the necessary evidence has been fully reviewed and published. Without this, the entire report’s credibility will be jeopardized.
• The proposed dose constraints (Section 6, Table 7) require a full justification and basis; specifically, does each level carry a risk significant enough to justify the proposed activities? If so, what is the basis for such a recommendation? This is particularly the case when the compliance with constraints is deemed “obligatory.”
2. CONSISTENCY NEEDS TO BE MAINTAINED. It is important to maintain consistency not only throughout the proposed guidance but also with previous ICRP documents such as Report No. 60. A few of these issues are listed below:
• The term “exclusion” was previously reserved for radiations that are not amenable to control, such as for cosmic rays or potassium-40 in the human body. This was stated in Report No. 60 and is a reasonable practice. However, the newly proposed term on exclusion seems to include those considered to be part of the “exemption,” meaning that the resulting dose implications for these levels would be too small to be of concern. It would be much better to separate the two terms (exclusion and exemption) to avoid confusion. Such a separation is clear from the IAEA (i.e., DS 161, which also includes the term “clearance” for release from existing regulatory confines).
• Following the previous comment, the recommended exclusion levels (in terms of specific radioactive concentration, Table 10) would be both redundant and meaningless. The recommended 0.01 mSv per year (Table 7) has already specified a minimum value for any constraint. The derived concentration levels from 0.01 mSv would have “exempted” a wide range of radioactive materials from the protection system. Further, the recommended exclusion levels may add confusion to communication with stakeholders, as the public may be led to believe that the suggested values are the actual cleanup values (is 0.01 mSv intended to be used to derive the exemption levels?).
3. THE INCLUSION OF NONHUMAN CONSIDERATIONS IS NOT FULLY JUSTIFIED. Section 11 includes a short discussion on the need to include nonhuman factors in the protection system, even suggesting the use of “Reference Animals and Plants” to support the cause. Along this line, I have a few concerns:
• It is unclear how the proposed framework would accommodate the nonhuman considerations. Specifically, how do the three current principles of protection apply when the well beings of biota is taken into account?
• Most environmental impacts, as they are understood today, do not directly result from radiation. Rather, they are indirectly caused by related activities. They result from the need to protect humans from radiation exposure, such as the cleanup of contaminated lands. Such activities have resulted in considerable disturbance of the environment and destruction of the ecosystem. The report should focus on these types of activities in the discussion of environmental protection.
• It is unclear as to how the “derived consideration levels” from the Reference Animals and Plants will be applied to protect the environment. Please consider one thing: is there any evidence to show that, at current human protection levels, there is a possibility that some part of the environment would likely to be harmed? This might be a better way of looking at this matter before the approach is recommended. In short, the proposed approach is premature.
4. WITH THE INCREASED TREND IN MEDICAL APPLICATIONS, PROTECTION OF PUBLIC EXPOSURES SHOULD BE EMPHASIZED. The rapid increase in public exposures through medical applications (particularly diagnosis that require a CT scan) warrants special attention in this new report. More specific provisions on “justification” should be formulated, and proper precautions must be provided for these activities. In addition, the nonoccupational personnel associated with these activities (such as the receptionist or service personnel) at the clinics or hospitals may also warrant attention.
5. THE PROPOSED REPORT DOES NOT DISCUSS INTERVENTION ACTIVITIES. The proposed guidance sheds little light on intervention activities, which include the Chernobyl accident as well as potential incidents involving radioactive dispersal devices used by terrorists. At issue are the action levels beyond the recommended dose constraints, together with the justifications and basis. The Chernobyl accident occurred almost 20 years ago, and the nations involved still lack a viable approach to such issues as affected residents returning to their indigenous living places. The emerging terrorist concerns also warrant more specific guidance regarding protecting first responders, relocating the affected population, and decontaminating the contaminated properties. The ICRP should pay more attention to such emerging issues.
6. THE ROLE OF “POTENTIAL EXPOSURES” IN THE PROTECTION SYSTEM IS UNCLEAR. Although potential doses are discussed in Section 10, it is unclear as to whether the potential exposures are meant to be part of the optimization process or that they have a place in regulatory compliance. If they are part of the optimization process, what is their role in ALARA? What would the risk constraints be if the potential dose is to be used for compliance purposes?
7. THE IMPORTANCE OF COLLECTIVE DOSE SHOULD NOT BE IGNORED IN CERTAIN PRACTICES. Under the current proposal, the emphasis is largely on protecting individuals. However, it should be noted that in cases where applications of a practice could be extensive, collective doses should be taken into account, such as by means of setting a goal for controlling the spread of exposure to a greater populations. Such a concern may arise concerning the release of exempt materials to the public.
8. THE BOTTOM LINE QUESTION IS: WETHER THE PROPOSED CHANGES WARRANT THE PRICES ASSOCIATED WITH THE REGULATORY EFFORTS? The ICRP needs to provide a very persuasive argument regarding the potential benefits of the proposed changes in radiation protection, i.e., in terms of the overall enhancement in protecting the workers and public. This is in light of the tremendous efforts and significant public and private funds that are likely to be spent in accommodating the proposed changes by the competent authorities in each nation. Given that the proposed report still lacks a number of key supporting documents (at least not yet completed), the ICRP should take the time in publishing this report until a later time.