The HPF experiment is carried out in a water conducting shear zone (AU 126) in the radiation controlled zone of the GTS. A series of ten boreholes (10 - 14 metres long) intersect the shear zone and allow dipole flow fields to be established in the shear zone (BOHP 98.003 and BOHP 98.001) as injection and extraction boreholes respectively).

Other boreholes in the area are used for hydraulic testing and periodic sampling. The large red tubes visible in the picture below represent the overcoring of the shear zone, which occured after the final tracer test involving more strongly sorbing radionuclides.

Location of the HPF site within the GTS

Borehole layout within HPF site

The layout plans for the experimental set up at the injection and extraction boreholes are shown below.

Instrumentation Dipole Injection Side

Instrumentation Dipole Extraction Side