Neutron and Positron Techniques for Fluid Transfer System Analysis and Remote Temperature and Stress Measurement

Nonintrusive radiation techniques have been routinely used, since 1970, for the determination of metal component movements and clearances within engines using high-energy x-rays. Oil system operation was first analyzed using “cold” neutrons in 1975 and, since 1980, positron-emitting isotope tomography has been developed using multiwire proportional counters to determine the X, Y, and Z coordinates of labeled oil volumes within engines. The tomographic system will allow a plane-by-plane inspection across an engine or rig to be carried out using radioisotope images overlaid by an engine general arrangement drawing. It is presently proposed that epithermal neutrons may be used for remote, noninvasive metal temperature measurement within engines or rigs. Finally, neutron diffraction may also be used for internal stress determination within compressor or turbine disks. Consideration is being given to carrying out remote stress measurements in a spinning pit or, perhaps, within an engine using this technique.