Measurement of void fraction by fast neutrons

The feasibility of using fast neutron moderation and scattering, and attenuation as means for measurement of void fraction in hydrogenous two phase flow was studied. Various geometries and different size channels were tested to examine the adaptability of the method to different arrangements. Experiments with static and dynamic voids were performed. For static tests, two phase air-water mixtures were simulated using various size plexiglass mock-ups in cylindrical channels. In dynamic experiments, the neutron techniques were tested in actual air water mixtures using different size cylindrical channels. A small californium 252 source was used as the source of neutrons. The proposed techniques for measurement of void fraction in hydrogenous two phase mixtures proved suitable. The feasibility of utilization of a small CF-252 neutron source for void fraction measurements was demonstrated as the neutron flux provided by the small source used in this study proved to be adequate.