Uranium-235 Measurement in Waste Material by Resonance Neutron Radiography

  The use of resonance neutron radiography as a means of monitoring the amount of ²³⁵U in waste material is investigated. A matrix material simulating incinerator ash is inoculated with ²³⁵U in concentrations ranging from 4.8 × 10⁻⁴ to 4.6 × 10⁻³ g/cm³. The observed uncertainty agrees well with an analytical model and ranges from 16% for the lowest concentration to 2.5% for the highest concentration. The effect of inhomogeneity of matrix and sample is determined and found to be in agreement with analytical models. The technique is demonstrated on sample sizes ranging from 2-ℓ bottles to 55-gal drums.