|DOE Office of Air, Water and Radiation Protection Policy and Guidance Comments on the Draft 2005 Recommendations of the International Commission on Radiological Protection
Stephen Domotor and Andrew Wallo
December 30, 2004
The comments which follow are made from the viewpoint of issues that would appear to have a significant impact on our ability to consider implementation of the science and policy recommendations within the United States.
Schedule and Supporting Information:
We appreciate the public consultation process that has occurred to date, and the opportunity to provide our thoughts on the draft recommendations. We are pleased to learn of the changes in schedule for the recommendations, and we look forward to additional opportunities for discussion and input.
There are a number of instances where the draft recommendations appear to be a “work-in-progress”. There are at least four major “foundation” documents that should provide the technical basis for the 2005 Recommendations, but these documents are not available for our review, and will not be available for review until after the next Main Commission meeting in March 2005. Consequently, much of the information needed to understand the basis for, and implications of the recommendations is not yet available. For example, even basic elements of the system such as the protected individual are not yet clearly defined. Are the limits and constraints to be applied to an average member of a critical group, a representative maximum exposed individual (a 90th percentile dose), or…? The lack of this type of information makes it difficult to understand the degree to which changes can be considered and justified in a regulatory analysis as required by legislation within the United States. We encourage the ICRP to use the comments on the draft 2005 Recommendations as input in preparing the foundations documents that have not yet been completed.
Implications for Current Regulatory Framework:
The recommendations, as presented, are not likely to result in substantial improvements to public health and safety as measured by doses received by individual workers and members of the public. We support improvements to the underlying scientific basis and calculations of dose as desirable to improve realism in conducting risk informed regulation. We also support clarifying issues that have been difficult to understand and implement from ICRP Publication 60. However the draft 2005 Recommendations also propose a number of changes in terms, philosophy, and regulatory approach that, taken as a whole, could necessitate time-consuming, contentious, and possibly expensive changes to documents prepared by national regulatory authorities. The draft, as currently presented, is not internally consistent on some of the concepts and terms, and in many parts is not sufficiently clear and explicit to be useable as a basis for decisions on radiation protection programs. Thus the regulatory agencies attempting to implement the recommendations could face significant regulatory analysis and justification challenges. The ICRP is encouraged to reconsider the need for many of the changes that will necessitate modification of existing regulatory programs that already achieve the protection objectives of the ICRP. In particular, we believe that the ICRP should be able to explain how proposed changes provide a level of improvement to public and worker protection that is commensurate with potential costs of implementation to either the regulatory systems (e.g., government costs) or the regulated community.
Basis for Quantitative Recommendations:
ICRP appears to be moving away from linking the dose and risk information with the considerations for setting the quantitative values. The proposed recommendations use background radiation exposure as a benchmark for determining whether regulatory action is needed. While a relationship can certainly be implied in this presentation, the more formal rationale for the recommendations appears to have been lost. One consequence of moving away from dose and risk is that it is unlikely that a unified (i.e., harmonized) system for controlling chemical and radioactive pollutants can be developed. Although our knowledge of radiation effects is subject to uncertainty, and we recognize the complex relationship that exists, we believe that the information should be used to assist in uniformly treating public health and safety hazards. Although background radiation may be one attribute that should be considered in establishing limits for the protection system in cannot be done independently of the exposure-dose-risk-detriment relationships and associated cost and benefit considerations of regulating, controlling, or intervening in situations as determined necessary by the evaluation of these considerations. It does not seem (or at least it is not adequately justified in the document) that background comparisons can be the primary basis of protection system limitations.
ICRP proposes adopting a system of protection that appears to consist of multiple tiers of constraints and limits. Practically speaking, such systems already exist in the United States and elsewhere, although the terminology may be different. Unfortunately, the current draft recommendations do not add to a coherent or simplified understanding of the general system of radiological protection, and can be read to suggest that significant changes should be made.
The regulatory usage (legal definition) of the term “limit” and its relationship to the recommended constraints has not been adequately described, and we believe this is different from the way in which the ICRP has used the term. For example, restrictions on individual dose from specified sources (e.g., source-constraints) “provide a level of protection for individuals that should be considered as obligatory and not maintaining these levels of protection should be considered as a failure.” It is unclear how this differs from the legal usage of the term “limit” by regulatory agencies. What may be more useful is a non-jargon explanation that an individual should be afforded the recommended level of protection from all sources, and that regulators and users must work together to establish a logical, predictable system for assuring that this is achieved for each type of exposure situation.
Finally, a tiered system of constraints as proposed may not promote international consistency (harmonization) in the establishment of source constraints, because the recommendation is that national authorities establish constraints at values less than the recommended maximum constraints. The ICRP is encouraged to remove the inconsistencies in, and clarify the use of, the term constraint in the recommendations.
The role of collective dose in optimization has been substantially revised, and it is not clear that the changes improve the optimization process and protection system. It would be more useful for the ICRP to provide additional guidance on how collective dose should be applied and under what circumstances it should not be used or rather is not useful or significant in the decision-making process. Collective dose, when properly constrained to specific time periods, populations, and locations, is a useful regulatory analysis tool and attribute in making decisions. Conversely, collective dose can be misused in certain circumstances and that misuse can result in poor decisions. To avoid such misapplications, guidance needs to limit unconstrained application of collective dose (e.g., infinite times and distances) and ensure consistent application (comparable over reasonable times, distances and population doses ) between the alternatives being evaluated under the optimization process. The draft 2005 Recommendations suggest the use of a dose matrix for decision making, but no details are provided on the quantitative or qualitative uses of such a matrix. It is not obvious whether the dose matrix replaces the use of collective dose, or provides a framework for the appropriate application of the concept. The ICRP is encouraged to clarify the conceptual considerations as well as in practical application of collective dose and the dose matrix.
The draft recommendations provide guidance for exposure of non-patient members of the public and care-givers in medicine that appears to be incomplete and potentially inconsistent with other exposure recommendations. In particular, detriment to non-patients is called secondary and constraints for care givers do not recognize circumstances where children or pregnant females may be present. The ICRP is encouraged to clarify how to provide consistent protection for these individuals.
Exemption and Exclusion:
The ICRP has provided significant new recommendations in the area of exemption and exclusion. Some of these ideas may be very useful for a logical and coherent radiation protection framework. However, the draft 2005 Recommendations do not present a clear and consistent approach to managing low doses and controlling small quantities of radioactive material. For example, the ICRP system of radiological protection generally applies to any actual or potential exposure, whatever its magnitude. In the case of very low levels of exposure (e.g., <10 ìSv per yr) from radioactive materials, application of the optimization principle would indicate that no additional protective action needs to be undertaken. Yet, some items will be excluded from regulatory control without regard to the question of whether anything within reason can be done to control them. Finally, the draft 2005 Recommendations suggest that materials with activity concentrations less than or equal to levels that are associated with 10 ìSv per yr may be considered to be nonradioactive and thus excluded from radiological control. The ICRP is encouraged to reexamine the conflicts within the numeric and conceptual recommendations throughout the document and present a clear and coherent approach.