2011 Volume 10 Issue 3 Pages 194-204
At the Ningyo-Toge Environmental Engineering Center of JAEA, the uranium enrichment plant has entered the decommissioning stage now. The gas centrifuge in this plant is contaminated by intermediate uranium fluoride. For the reasonable decommissioning of this plant, it has been planned to carry out the IF7 treatment of the gas centrifuge for system decontamination before dismantling. Although a few studies about IF7 treatment have been carried out in the small scale, the details about the decontamination performance in terms of level and time, for example, have not been clarified. Therefore, in order to clarify the decontamination performance, this study was carried out for full-scale examination using the actual gas centrifuge cascade. This paper shows the investigation result of reasonable IF7 treatment condition and the full-scale examination result under this IF7 treatment condition. As a result, it could be confirmed that 99% of intermediate uranium fluoride in the cascade was removed after 60 days. Furthermore, in this study, we carried out the examination of IF7 gas production needed in the IF7 treatment examination, too. This paper shows the investigation result of reasonable IF7 production condition and the full-scale examination result. As a result, it could be proved that 3,355 kg-IF7 gas was produced.
