[3C01-04] Contaminated Concrete at Fukushima Daiichi NPS Site 1

[3C04] Study on the Radionuclide Contamination Mechanisms of Concrete and the Estimation of Distribution of Radionuclides

(7)Effects of concrete characters on the Cs/Sr penetration in the real concentration ranges

*Kazuo Yamada¹, Rohith Kiran², Ippei Maruyama², Go Igarashi³, Sayuri Tomita⁴ (1. NIES, 2. Nagoya Univ., 3. Univ. of Tokyo, 4. Taiheiyo Consultant)

Keywords:penetration, Cs, Sr, Concrete, Imaging plate, Actual concentration, Degradation, Carbonation, Drying

Regarding the penetration of Cs and Sr important for the contamination estimation and disposal of radioactive wastes, it is investigated that the effects of concrete characters on them in the condition of realistic concentration range have been investigated experimentally. Although the ion penetration is affected by ion uptake by solid phase, the degree of effect is depended on the ion concentration. Then, the penetration experiments at various concentration range including 10μM, which is close to the real concentration just after the accident. As results, the Cs penetration was affected by clay content and especially by carbonation of cement increasing Cs uptake significantly. This effect was significant at low concentration range. When water-saturated carbonated smaples were immersed in 10 μM for 56 days, the penetration depth of Cs was 2 mm. For Sr, the penetration depth was much less then Cs. However, under dried condition, in carbonated sample, by water suction after vacuum treatment, both Cs and Sr were transported to the depth of 10-20 mm during 40 min.