Migration of 85Sr in unsaturated Chinese Loess: An in-situ test

As part of a co-operative research project between the China Institute for Radiation Protection (CIRP) and the Japan Atomic Energy Research Institute (JAERI) on safety assessment method for shallow land disposal of low level radioactive wastes, the migration of 85Sr in unsaturated Chinese loess under natural and artificial rainfall conditions was in-situ investigated. 3H was used for obtaining the migration velocity of the moisture water in the test zone. The result of the 2-year test indicated that under natural rainfall conditions, the migration of 85Sr is a combination of downward and upward movements. It moves down in summer and moves up in winter. Under artificial rainfall conditions the migration of 85Sr is a velocity-change process. It migrates down faster in summer and slower in winter. This phenomenon is considered to be caused by the dry winter and relatively wet summer.