R4: Mineral sciences of the Earth surface

[R4-15] Super-Radioactive Unit 1-Derived Particles from Fukushima Daiichi ~Properties and Environmental Impacts~

*Satoshi Utsunomiya¹, Kazuya Morooka¹, Kazuki Fueda¹, Shinya Yamasaki², Kenji Horie³, Gareth T. W. Law⁶, Bernd Grambow⁵, Rodney C. Ewing⁴ (1. Kyushu Univ., 2. Tsukuba Univ., 3. NIPR, 4. Stanford Univ., 5. Univ. Nantes, 6. Univ. Helsinki)

Keywords:Fukushima Daiichi, Super radioactive particles, Cesium

We have characterized super-radioactive particles derived from FDNPP Unit1. Two particles have the highest particle-associated ^134+137Cs activity, 6.1 × 10⁵ and 2.5 × 10⁶ Bq per particle after decay-correction to March 2011. The particle with the highest Cs activity has a glassy carbon core and a surface that is embedded with numerous micro-particles: Pb–Sn alloy, fibrous Al-silicate, Ca-carbonate or hydroxide, and quartz. The composition of the micro-particles on FTB26 reflects the composition of airborne particles at the moment of the H₂ explosion in Unit 1.