Neutron-gamma hodoscope detection of fissile materials

The neutron-gamma hodoscope has been developed to make use of two aspects of the fission process that occur during severe safety testing of nuclear reactor fuel; fission-product heating that induces realistic effects in the fuel and penetrating radiation that enables the imaging of fuel behavior. During in-pile transient reactor experiments, the radiation which escapes from the test fuel, its surrounding coolant, and a thick-walled container is detected by a large collimated array that produced cineradiographic images. Phenomena observed in hundreds of destructive experiments have included pre-failure fuel motion, cladding breach, and post-failure fuel motion. On the basis of this successful 25-year experience, application of hodoscope techniques to arms control treaty verification is now being studied. 7 refs., 13 figs