Multispectral Active Neutron Interrogation Analysis

Year
2013
Author(s)
Jason M. Lewis - Nuclear Engineering, University of Florida
Kelly A. Jordan - Nuclear Engineering, University of Florida
Dominik Rätz - Nuclear Engineering, University of Florida
Abstract
The non-destructive assay (NDA) of spent nuclear fuel is an increasingly important re- search area due to the need in international safeguards for a direct and independent method of determining plutonium (Pu) mass in spent fuel. A new method has been developed that iteratively determines the isotopic masses of fissionable isotopes in a fuel sample from the fis- sion rates induced in the fuel sample at different interrogating neutron energies using readily available neutron generators and neutron sources. This method, called MANIA (Multispectral Active Neutron Interrogation Analysis), uses the fission rates from the active neutron inter- rogation in a system of linear equations that is solved using a convex optimization algorithm which allows for a variety of constraints to be placed on the sought after solution. To compen- sate for the effects of self shielding, iteration occurs between the measured fission rates and the simulated fission rates from an MCNP model of the irradiation setup. This method has been tested with synthetic fission rates generated in MCNP for a variety of sample geometries, dimensions, and isotopic compositions; and converges to the correct isotopic composition.