The site investigation in Forsmark was conducted between 2002 and 2007 in an area – referred to here as a candidate area – of approximately ten square kilometres southeast of the Forsmark Nuclear Power Plant. Early on in the study, site investigations were focused on the rock in the northwestern part of the candidate area, which is the area closest to the Forsmark Nuclear Power Plant.
Investigations
The site investigations were comprehensive and included drilling down into the rock, bringing up deep cores and obtaining data on these cores and in the drill holes. We also investigated the forest and land, sea and streams, and installed instruments for long-term measurements of the chemical composition of the groundwater and its flow through the rock. An overall picture gradually developed to form the basis for the site selection.
25 cored boreholes
We drilled 25 cored boreholes, of which 19 were more than 500 metres long, and thus developed a picture of a rock that was surprisingly lacking in fractures and “dry” at greater depths, but with all the more water flow at the surface. The rock that lacked fractures has probably contributed to rock tensions that are somewhat greater than normal. These are not, however, so great as to prevent the placement of a final repository at a depth of between 450 and 500 metres.
In the forest and on land
An extensive inventory of the flora and fauna on land and in the lakes and sea were conducted in conjunction with the site investigation. This was done to obtain a good Environmental Impact Assessment (EIA) for the construction and operation of a final repository, as well as to enable us to check whether or not our field investigations had affected the flora and fauna.