|Comments on the ICRP Task Group Report: The Optimisation of Radiological Protection – Broadening the Process
Prepared by the Federal Guidance Subcommittee of the US Interagency Steering Committee on Radiation Standards (ISCORS)
The following comments represent a consensus of views from participating members of the subcommittee representing the Nuclear Regulatory Commission (NRC), the Environmental Protection Agency (EPA), the Department of Energy (DOE) and the Agency for Toxic Substances and Disease Registry (ATSDR) of the Department of Health and Human Services.
We are pleased to participate in the open process of consultation offered by the International Commission on Radiological Protection (ICRP). Our comments on this Foundation Document are informed by our previous review of the first public draft of the proposed general recommendations referred to as RP 05.
The report goes further than previous ICRP publications towards broadening the process of optimization. We believe that it attempts to encompass some concepts that are not necessarily a part of optimization. While we understand their role in the practice of radiation protection, we question whether topics such as “safety culture” and BAT are properly classified as optimization. There is also a concern that broadening the process of optimization blurs the well-understood lines between justification, optimization and limitation.
The tone of this Foundation Document often implies that optimization always results in dose reduction, but sometimes optimization will result in a decision to permit higher doses than those achievable through excessive measures. Although the common sense approach to optimization – continuing to ask whether all that can reasonably done to lower doses has been done – is one we generally endorse, we believe that there are circumstances where optimization will lead to a practical endpoint. In the report, endpoints are endorsed in paragraph 56, but then called into question in paragraph 59. For example, regulatory decisions regarding cleanup of contaminated sites and other interventions that result from an optimization process ought to be considered final unless new information later becomes available that invalidates the assumptions used to arrive at a decision (e.g., a site cleaned up for industrial use is later selected for residential development).
For cleanup decisions, the optimization process will need to be applied to all the hazards at a site to arrive at appropriate cleanup levels. We recommend that a section be added that discusses integrating radiation, hazardous chemicals and other hazards into the optimization process.
Discussion of optimization of medical exposures should address exposures to the public in the absence of any direct benefit, such as secondary exposures to the public from patients undergoing treatment with radioactive iodine.
The section on stakeholder involvement needs to be tightened up and made more consistent. We agree with the conclusions in paragraph 54, but some of the preceding paragraphs could lead to one to believe that stakeholder involvement is a never-ending loop of consultations, forestalling necessary decision-making. Less detail may be the solution.
Terminology is not consistent throughout the report. There is a lack of clarity in some of the definitions, and this problem is also reflected in Figure 1. In particular, we are disappointed that the report fails to answer many of the questions we had in RP 05 concerning the definition and use of constraints. Beyond blurring the lines between the three principles, as we have already mentioned, Figure 1 raises additional questions about the role of constraints. For example, are authorized levels to be considered as enforceable limits? The report needs to clearly present the relationship between constraints and optimization.
Throughout the appendices, we find material that is duplicative of material in the body of the report. Some of the text is either missing or poorly worded. Finally, some of the material in the appendices is irrelevant to the topic of optimization. The goal of presenting useful applications of optimization is good, but the examples given often stray beyond optimization. In particular, we have concerns about the radon example where an entire approach for controlling radon is laid out which is somewhat inconsistent with successful programs in the US and elsewhere. The US radon program relies on voluntary testing and recommends that steps be taken to reduce radon when indoor concentrations exceed an Action Level. We believe that this approach is more likely to result in homeowners taking action than a system that relies on a case by case (house by house) optimization process.
We encourage the ICRP to work towards improving and completing the Foundation Documents before taking up the revisions to RP 05. The timetable for this process should not be rushed.
Thank you for the opportunity to offer these comments.