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 2017-17



Flow and Electrical Conductivity Measurements During Long-Term Pumping of Drillhole OL-KR6 at Olkiluoto, Results from November 2015 and September 2016 Measurements


Pekkanen, J.



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The Posiva Flow Log, Difference Flow Method (PFL DIFF) uses a flowmeter that incorporates a flow guide and can be used for relatively quick determinations of hydraulic conductivity and hydraulic head in fractures/fractured zones in cored drillholes. This report presents the principles of the method and results of measurements carried out in drillhole OL-KR6 at the Olkiluoto investigation site in November 2015 and September 2016.

Previously reported results from measurements made between June 2008 and June 2014 are also presented for comparison. In this study the Posiva Flow Log method was used for measurements of flow and electrical conductivity of water during long-term pumping.

The aim of the measurements was to detect possible changes in the electrical conductivity of fracture-specific water during the long-term pumping period. Flow rates from fractures were also measured.

The measurements in drillhole OL-KR6 were carried out in the depth intervals c. 24 m - 64 m, 98 m - 140 m and 396 m - 424 m. The flow rate into a 0.5 m long test section was measured using 0.1 m point intervals.

The occurrence of saline water in the drillhole was studied by electrical conductivity measurements. The target fractures were chosen on the basis of their flow rates and the fractures were the same as in the earlier measurements.

A modified EC-electrode setup was in use in November 2015 and September 2016 measurements. Modification was added to the PFL DIFF probe for the 2014 measurements. The purpose of this modification was to guide the fracture water to flow along pre-determined route and to protect the EC-electrode from the surrounding drillhole water. The purpose of this modification was to prevent possible distortion of the measured electrical conductivity value.


Groundwater, flow, measurement, bedrock, drillhole, electrical conductivity, Posiva Flow Log


WR 2017-17_web (pdf) (89 MB)


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