Posiva publishes Working Reports and Posiva Reports. From the year 2006 nearly all the reports have been published on our webpage and they can be found in the databank. In the databank you can also find our Annual Reviews and some other publications as well. You can also find print-quality pictures and useful links in the databank.

Recent publications

Workreport 2017-46



Results of Monitoring at Olkiluoto in 2016, Foreign Materials


Ylöstalo, R.



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This report focuses on foreign materials introduced into the final disposal facility of spent nuclear fuel. The foreign materials are materials which are not part of the engineered multi-barrier system (KBS-3V) nor the natural environment. Foreign materials management and control is one of the safety critical functions of the final disposal facility. The other safety critical functions are monitoring of leakages, excavation damage zone (EDZ) and drilling in the final disposal facility.

The updated ONKALO monitoring program was introduced in the beginning of 2012. Monitoring of foreign materials was taken out of the ONKALO monitoring program in 2016 and it continued as an individual function coupled with the safety critical materials (TLTA) management of TVO. Monitoring of the effects of foreign materials on outlet waters of the final disposal facility was taken under the monitoring program of hydrogeochemistry and environmental monitoring program. Foreign materials in 2016 are reported in this report according to the monitoring program before the reformation of the year 2016.

Excavation of the access tunnel was finished in 2012 and excavation related to the demonstration tunnels area and the technical facilities in 2013. The exhaust air shaft 1 (ONK-KU2) was completed in 2011. Both personnel shaft 1 (ONK-KU1) and inlet air shaft (ONK-KU3) were raise bored down to the final level at -455 m in spring 2014. In 2016 Posiva was granted the construction permit of the final disposal facility and rock works of that facility were started. The spaces of ONKALO were also merged with the final disposal facility. In the year the excavated volume of the final disposal facility was 35 479 m3. At the end of the year the total volume of the facility (previous ONKALO area and the excavation in 2016) was 354 583 m3.

All waters used during the excavation of the final disposal facility were pumped up to the surface into a sedimentation pool. In 2016 the effects of the foreign materials on the environment were monitored by sampling the sedimentation pool water.


Foreign materials, disposal of spent nuclear fuel, monitoring, Olkiluoto, ONKALO, final disposal facility


WR 2017-46_web (pdf) (2.9 MB)


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