Experimental analyses of iodine behavior under severe accident conditions with ART

The fission products (FP) behavior analysis code ART developed at JAERI simulates a FP transport and deposition in a reactor coolant system and containment during severe accidents. As part of the code development and verification, several experimental analyses have been conducted. In the JAERI's WAVE experiment, the effect of nitrogen or steam carrier gases on the cesium iodide (CsI) behavior in piping was recently investigated. The ART analysis for nitrogen agreed with the experimental results by reflecting the detailed thermo-fluiddynamic calculation on the CsI aerosol behavior analysis. On the contrary, the analysis for steam did not agree well with the experimental results because observed enhancement of aerosol growth cannot be explained by existing models. Moreover, the newly developed empirical models on iodine chemistry in water were examined for the ACE/RTF 3B experiment. The analysis showed that those models have a fundamental analytical capability. (orig.)