[en] The operation of the emergency core cooling system and its related steam-binding problems in pressurized water reactors are the subject of a cooperative study by the United States, Germany, and Japan. Lawrence Livermore Laboratory and EG and G, Inc., San Ramon Operations, are responsible for the design, hardware, and software of the 80.8-mm and 113-mm spool piece measurement systems for the German Primarkreislauf (PKL) Test Facility at Kraftwerk Union in Erlangen, West Germany. Four PKL spool pieces each containing a flow turbine, drag screen, three-beam densitometer, and pressure and temperature probes were constructed and tested to measure single-phase and two-phase steam and water flow parameters. Individual phase velocities, mass flow rates, and densities were calculated from the analytical relationships presented. These calculated and measured parameters were compared to those parameters determined from the test facility instrumentation at Wyle Laboratories. Error analyses were performed, and individual test results were presented for both horizontal and vertical flows. The various flow regimes tested included annular mist, slug, froth, stratified wavy, and homogeneous flow of water or superheated steam