[3D07-10] Evaluation of Contamination Distribution

[3D07] Prediction of infiltrated contamination by C-14 in a concrete from reference data

*Norikazu Kinoshita¹, Kazuaki Kosako¹, Hitoshi Nakashima¹, Kazuyuki Torii¹, Yuki Sasaki¹, Hiroshi Kimura¹ (1. Shimizu)

Keywords:concrete, C-14, CO2, diffusion

Removal of contaminated material enables to reduce the amount of low-level radioactive waste in the decommissioning of nuclear power plants. Extensive contamination by ¹⁴C would occur in a concrete of nuclear power plants. A diffusion model allows to predict distribution of the contamination, assuming the CO₂ containing ¹⁴C infiltrates in a concrete from surface by diffusion. We estimated a diffusion coefficient of CO₂ in a mortar from carbonation data of concrete published as a paper. The diffusion coefficient related with the W/C ratio. Eventually, a depth profile of the relative concentration for ¹⁴C in the concrete which is exposed by CO₂ for a certain time, was estimated using the diffusion coefficient.