Atomic Energy Society of Japan

In order to investigate the migration of radium isotopes in the former open-pit mining site of the Ningyo-toge Environmental Engineering Center, the U- and Th-series nuclides including radium isotopes in the boring core samples inside and outside the site were analyzed. Additionally, to clarify the partitions of ²²⁶Ra in the solid phase, sequential extraction experiments were conducted on the Ningyo-Toge layer and the weathered granite layer. As a result, it was estimated that the radium isotopes were migrated from the Ningyo-Toge layer to the weathered granite layer below it.