[3G01-05] Behavior of Radioactive Nuclides & Fuel Debris 1

[3G05] Estimation of Cs distribution and characteristics in the reactor under severe accident

(5)Summary

*Shuhei Miwa¹, Hidetoshi Karasawa¹, Chiaki Kino², Kunihisa Nakajima¹, Eriko Suzuki¹, Junpei Imoto¹ (1. JAEA, 2. IAE)

Keywords:Cesium, Chemisorption, Stainless steel, Water solubility, ECUME, SAMPSON

We investigated the Cs distribution and characteristics in the upper structure of the reactor pressure vessel in TEPCO Fukushima Daiichi Nuclear Power Station (1F) based on the data on the amount of Cs chemisorbed compound onto stainless steel in the upper structure calculated by severe accident analysis code SAMPSON with improved Cs chemisorption model, the chemical form and water solubility of Cs chemisorbed compounds obtained by experiments which are prerequisite for the evaluation of long-term behaviors. The results indicate that the amount of insoluble Cs chemisorbed compounds can be lower than that estimated by using existing Cs chemisorption model.