The ability of inspection agencies and facility operators to measure powders containing several actinides is increasingly necessary as new reprocessing techniques and fuel forms are being developed. These powders are difficult to measure with nondestructive assay (NDA) techniques because neutrons emitted from induced and spontaneous fission of different nuclides are very similar. A neutron multiplicity technique based on first principle methods was developed to measure these powders by exploiting isotope-specific nuclear properties, such as the energy-dependent fission cross sections and the neutron induced fission neutron multiplicity. This technique was tested through extensive simulations using the Monte Carlo N-Particle eXtended (MCNPX) code and by one measurement campaign using the Active Well Coincidence Counter (AWCC) and two measurement campaigns using the Epithermal Neutron Multiplicity Counter (ENMC) with various (Î±,n) sources and actinide materials. Four potential applications of this first principle technique have been identified: (1) quantitative measurement of uranium, neptunium, plutonium, and americium materials; (2) quantitative measurement of mixed oxide (MOX) materials; (3) quantitative measurement of uranium materials; and (4) weapons verification in arms control agreements. This technique still has several challenges which need to be overcome, the largest of these being the challenge of having high-precision active and passive measurements to produce results with acceptably small uncertainties.
An AWCC located at the Joint Research Center in Ispra, Italy. Pictured (from left): Braden Goddard, Chris Ryan, Dr. Paolo Peerani.
- B. Goddard and S. Croft, "High-Fidelity Passive Neutron Multiplicity Measurements and Simulations of Uranium Oxide", Nuclear Instruments and Methods in Physics Research A 712, 147–156 (2013).
- B. Goddard, "Quantitative NDA Measurements of Advanced Reprocessing Product Materials Containing U, Np, Pu, and Am", Ph.D. Dissertation, Nuclear Engineering, Texas A&M University, College Station, TX (2013).
- B. Goddard, W. Charlton, M. Swinhoe, Paolo Peerani, "Expanding the Capabilities of Neutron Multiplicity Measurements: Conclusions from a Four Year Project", Proceedings of the 35th ESARDA Annual Meeting, 27-30 May, 2013, Bruges, Belgium.
- B. Goddard, W. Charlton, L. Evans, and P. Peerani, "An Analysis Technique for Active Neutron Multiplicity Measurements Based on First Principles", 53rd Annual Meeting of the Institute of Nuclear Materials Management, Orlando, Florida, 15-19 July 2012.
- B. Goddard, W. Charlton, C. Gariazzo, P. Peerani, "A Concept for Quantitative NDA Measurements of Advanced Reprocessing Product Materials", Proceedings of GLOBAL 2011, Makuhar, Japan, December 11-16, 2011.
- B. Goddard, W.S. Charlton, C. Gariazzo, P. Peerani, "A Concept for Quantitative NDA MOX Measurements Using Only Neutron Radiation", Proceedings of the INMM 52nd Annual Meeting, Palm Desert, CA, July 17-21, 2011.