Low-dose Extrapolation of Radiation-Related Cancer Risk

Draft document: Low-dose Extrapolation of Radiation-Related Cancer Risk
Submitted by Shinichiro Miyazaki, The Federal of Electric Power Companies(Japan)
Commenting on behalf of the organisation

We appreciate the consultation process and the opportunity to provide our comments on the report. Comment-‚P Based on the Chapter 2.4.4, it is impossible to identify the risk of radiation exposure in the range of moderate (~100 mGy) . Any evidence of risk in the moderate range is not expected, so extrapolation of risk estimate from moderately high range to moderate should be reconsidered. The undetected risk in this range should be explained clearly in Chapter 7 on the base of uncertainty. In addition, the comparison with other risks will lead the better understanding for the necessity of extrapolation. In addition, gradualism (6.2.8 Gradualism in DDREF and threshold effects) should be developed and included with clearer image for explaining low dose risk. Using the gradualism, the present concept of DDREF might be developed. And it is expected that public will become to be understandable the undetected risk in the low dose. Comment-2 Chapter 6 Quantitative Uncertainty Analysis 184p The comparison with other carcinogens is important and should be described in chapter 7 (Conclusions) in detail. Comment-3 Chapter 6 Quantitative Uncertainty Analysis Uncertainty regarding risk associated with low dose contains some different factors. In these factors, age and sex are particularly significant regarding individual (optimisation). By clarifying these in the radiological protection, the flexible and practical radiological protection system might be established. Commen-4 For setting the values of constraints, moving from risk-based approach(LNT) to natural background based is needed. In this context, if the constraint is used as the most fundamental level of protection, the relation between risk-base and natural background base should be clarified. Comment -5 Chapter 2. Epidemiological Consideration We are living in the natural radiation and have natural radioactivity in our bodies. In this context the epidemiological research results of high background areas are very informative because low dose and dose rate data and every generations data are involved. These data should be reflected in the document of C-1 and overall evaluation in terms of epidemiological data might be significant.