Task Group "Radiation Protection for Waste Disposal Containing Natural Radioactive Nuclides", 3; Our proposal of the important issues; Issues about radon, uncertainty of long term assessment and care for future generations

Saito, Tatsuo  

From 2017 June to 2019 March, our task group of radiation protection for wastes with natural radioactive nuclides studied issues about clearance and disposal of uranium bearing waste, concerning its billions-year halflife and build-up its dose with its progenies generation. Here we report about important of our issues. The first issue is uncertainty of long term safety assessment of near surface disposal. We proposed to introduce qualitative assessment for over several 10,000 year-long term safety assessment, difficult to show its dose, because of uncertainty of the assessment, but to show safety inclenation based on reliable quantitative assessment for 1,000 or 10,000 year. The second issue is radon generation of several thousands years after disposal. It is difficult to reduce radon with disposal facility design after several ten thousand years. We propose to discuss for safety standard for radon, such as clearance level for radon assessment, or reference level for existence situation for the sum of radon from natural soil and disposal wastes. Regarding the disposal of uranium waste from the viewpoint of "intergenerational ethics", the burden and responsibility to be taken regarding the balance of the burden between the future generation and the current generation could not be organized.