Hard X-ray photoelectron spectroscopy study for transport behavior of CsI in heating test simulating a BWR severe accident condition; Chemical effects of boron vapors

BWRシビアアクシデント条件を模擬した加熱試験におけるCsIの移行挙動の硬X線光電子分光による研究; ホウ素蒸気の化学影響

岡根 哲夫  ; 小畠 雅明  ; 佐藤 勇*; 小林 啓介*; 逢坂 正彦  ; 山上 浩志

Okane, Tetsuo; Kobata, Masaaki; Sato, Isamu*; Kobayashi, Keisuke*; Osaka, Masahiko; Yamagami, Hiroshi

Transport behavior of CsI in the heating test, which simulated a BWR severe accident, was investigated by hard X-ray photoelectron spectroscopy (HAXPES) with an emphasis on the chemical effect of boron vapors. CsI deposited on metal tube at temperatures ranging from 150C to 750C was reacted with vapor/aerosol BO, and the chemical form of reaction products on the sample surface was examined from the HAXPES spectra of core levels, e.g., Ni 2p, Cs 3d and I 3d levels, and valence band. For the samples at 300C, while the chemical form of major product on the sample surface without an exposure to BO was suggested to be CsI from the HAXPES spectra, an intensity ratio of Cs/I was dramatically reduced at the sample surface after the reaction with BO. The results suggest the possibility of significant decomposition of deposited CsI induced by the chemical reaction with BO at specific temperatures.