[en] The Posiva Flow Log/Difference flow method can be used for the relatively fast determination of water conductivity and hydraulic head in fractures/fractured zones in cored boreholes. In this method, a flow meter and a connected flow guide are used. This report presents the principles and results of the measurements carried out in boreholes KR34 - KR39, KR37B and KR39B at the Olkiluoto investigation site between May 2005 and April 2006. The measuring program varied between boreholes. The section length of the flow guide was 2 m and 0.5 m. The flow into the borehole or from the borehole to the bedrock was measured within the section lengths. This was carried out both with pumping and in natural (unpumped) conditions. Transmissivity (T) and hydraulic head of zones are calculated for the results, if a measurement in natural conditions was performed. The device also includes a sensor for single point resistance (SPR). SPR was always measured in connection with flow measurements, and it was registered when the tool was moving. The electric conductivity of fracture-specific water (EC) was measured in chosen fractures in some of the boreholes. The fractures were chosen on the basis of the measured flow from the fracture to the borehole. The EC of the borehole water was also measured. (orig.)