Behavior of radium in Ningyo-toge Environmental Engineering Center

Kuribara, Yuichi  ; Yamaguchi, Akiko*  ; Higaki, Shogo*; Ohara, Yoshiyuki; Takahashi, Yoshio*

In order to investigate the behavior of radium (Ra) in the Ningyo-toge Environmental Engineering Center, Ra/U activity ratio in two boring core samples in the center was analyzed with HPGe semiconductor detector. The Ra/U ratio was below 1 and over 1 in the U enriched and contained clay mineral layers, respectively. Based on the radioactive equilibrium and mass balance calculation, it was suggested that Ra and U eluted to groundwater migrated from the U enriched layer to the contained clay minerals layer when Ra was selectivity fixed on the contained clay mineral layer. EXAFS and micro-XRF-XANES-XRD for Ba, used as an analog of Ra, confirmed that Ba was adsorbed on clay minerals as IS complex, and Ra was expected to show similar behavior. Therefore, it was indicated that Ra migrated from U concentrated layer was adsorbed and fixed on clay minerals in the environment of the Ningyo-toge Environmental Engineering Center.