Olkiluoto nuclear power plant Olkiluoto Nuclear Power Plant is one of Finland's two nuclear power plants. The Olkiluoto plant consists of two reactors each 860 MW. One 1720 MW reactor is under construction. Supposed to start in 2011.
Onkalo All nuclear waste produced in Finland must be disposed in Finland. Olkiluoto has been determined to become the site of disposal of Finnish nuclear waste. Long term project, intend to start up in 2020.
Repository Access tunnel:5.5 km tunnel 1:10 Main characterisation level –420 m Lower characterisation level –530 m Repository Ventilation shaft
Ventilation shaft Depth: 530 meter deep. The ventilation shaft will be reamed up later. Our drilling demands was less than 1,75 meter deviation from vertical axis.
Olkiluoto 2005 Devico was first time hired in 2005 in Olkiluoto for a similar project Successful results, no survey shows more than 2 meters deviation from vertical axis. 3 steerings on the way down.
SMOY • Worked in cooperation with SMOY. • - Diamec U8 drill rig. • - NQ rods. • Triple tube Corac N3/50. • 2 shifts – App. 25 days to finish the borehole.
Directional drilling • Challenges: • - Stringent demands • - Find the correct direction. • Find the toolface. • Solutions: • Accurate surveying. • Repeated and overlapping surveying. • Some statistical approaches.
Drilling Drilled two sections à 9 meters. 100-110 meters:Dogleg setting 2.5 / Dogleg app. 7 320-330 meter:Dogleg setting 2.5 / Dogleg app. 5 No return water. Dark, very hard granite. Almost without fractures, but quart veins.
Results – 0-345 meters. PeeWee DeviFlex Smoy’s EMS North - East
Conclusion • Possible to orientate hole within stringent demands. • Some “confusing” survey results. • Important to know the steering capabilities of the DeviDrill in the rock. • Teamwork, teamwork! Easy cooperation on the drill site in this project.