Groundwater monitoring of the Rokkasho radioactive waste repository, Japan

A near-surface repository for low-level radioactive waste was constructed at the site of the Rokkasho centre and put into operation in December 1992. The first stage of the repository had a capacity of 200'000 barrels. In the meantime, the capacity was doubled to 400'000 barrels by the construction of a second unit.

Solexperts Hybrid Multi Packer Systems

As part of the monitoring programme, two groundwater monitoring systems of the type Solexperts Hybrid Multi Packer System (HMPS) were installed. In the first borehole, which is about 100 m deep, an HMPS 89 with 8 observation or sampling intervals was installed. In the second, almost 200 m deep borehole, an HMPS 131 with 14 observation and sampling intervals was installed.