Application of pulsed photon activation technique in single and two phase flow measurements

The Pulsed Photon Activation (PPA) technique for single-phase water flow and two phase air/water flow is analyzed for a 2.69-cm I.D. horizontal pipe. PPA measurements were performed at the RPI Gaerttner LINAC Laboratory using the 16O(γ,n)15O reaction, and was compared to the Pulsed Neutron Activation (PNA) technique in signal strength both analytically and experimentally. The identity between PPA and PNA in the accurate measurement of mass-weighted velocity by the transit-time method is also discussed. The measurement of global void fraction using non-intrusive radioactive tagging techniques is also discussed. An experimental technique was developed for controlling the direction of the PPA tagging beam and detailed flow structure of horizontal annular flow was revealed. The potential of 15O positron emission tagging techniques for single and two-phase flow measurements was demonstrated. Film thickness measurements along the circumference of horizontal annular flows were conducted using a resistivity needle probe, and theoretical models for predicting such film thickness distribution were also developed and analyzed