Evaluation of FP behavior models in SAs, 5; Evaluation of a chemical reaction model for Cs-I-B-H-O system in SA codes

Karasawa, Hidetoshi; Rizaal, M.   ; Miwa, Shuhei  ; Kino, Chiaki*

In SA analysis, the importance of chemical reactions related to FP behavior has been pointed out. For this reason, the amount of gaseous iodine produced was evaluated by a gaseous chemical reaction model using the ECUME database in the previous CsI-TeRRa experiment. In this study, we investigated the gas phase chemical reaction model for the CsI-BO-TeRRa experiment, which evaluated the influence of B on CsI behavior. In the experiment, the addition of BO increased the production of gaseous iodine by about 10 times. To explain this behavior, we set up a Cs-I-B-H-O reaction mechanism in which HBO generated from BO is reacted with CsI and CsOH to produce gaseous iodine. Calculations of the chemical reaction model using chemical reaction rates in the ECUME database confirmed an increase in gaseous iodine (about 26 times at 1,273 K) due to the addition of BO. The results showed that gaseous iodine was sufficiently produced at high temperatures, indicating the possibility of reproducing the TeRRa experiment by calculating chemical reactions during the transition of decreasing temperature.