Technology development of system chemical decontamination using iodine heptafluoride gas; Evaluation of IF treatment condition and uranium decontamination result

Ema, Akira ; Yokoyama, Kaoru; Nakatsuka, Yoshiaki; Shimaike, Masamitsu; Sugitsue, Noritake

In the centrifugation method uranium enrichment plant, the UF gas was supplied for a long term. The main uranium compounds are estimated to the middle fluorides UFx(4x=5). This middle fluoride is changed to UF and IF gas again by the reaction with IF. Using this reaction, the uranium compound in the plant was decontaminated. The IF treatment tests were executed to the plant in four treatment conditions. It is necessary to clarify the relation between IF treatment condition and decontamination results for the best treatment condition setting. Therefore, the decontamination development is evaluated using the result of the weight measurement of recovery UF and IF gas, the -ray measurement, and the ICP-MS analysis at the IF treatment tests. Then the technical knowledge to clarify the decontamination characteristic features is accumulated for analyzing the treatment trend, the treatment time, decontamination level and variation of the decontamination level.