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 (α,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.
- 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). See Document
- 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, and P. Peerani,
"A Concept for Quantitative NDA Measurements of Advanced Reprocessing Product Materials,"
Proceedings of GLOBAL 2011, Makuhar, Japan, December 11-16, 2011. See Document
- 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. See Document
An AWCC located at the Joint Research Center in Ispra, Italy. Pictured (from left): Braden Goddard, Chris Ryan, Dr. Paolo Peerani.