Neutron Resonance Transmission Analysis of Reactor Fuel Samples

Neutron resonance transmission analysis (NRTA) was used to measure the isotopic content of fresh and spent nuclear reactor fuel samples. Using the National Bureau of Standards 100-MeV electron Linac as a pulsed neutron source, neutron transmission spectra were measured for two samples of fresh reactor fuel and two samples of spent fuel. The transmission spectra were fit using the well-known and unique neutron cross sections for each isotope of interest. For the fresh fuel samples, the ²³⁵U and ²³⁸U contents were determined and compared to the results of a destructive analysis. Excellent agreement was obtained. For the spent fuel samples, the abundances of 11 actinides and 5 fission products were obtained. NRTA was shown to be a method for nondestructive analysis with high isotopic discrimination and high accuracy.