Non-destructive interrogation of nuclear waste barrels through muon
tomography: A Monte Carlo study based on dual-parameter analysis via
GEANT4 simulations
Abstract
The structural characterization of the sealed or shielded nuclear
materials constitutes an indispensable aspect that necessitates a
careful transportation, a limited interaction, and under certain
circumstances an on-site investigation for the nuclear fields including
but not limited to nuclear waste management, nuclear forensics, and
nuclear proliferation. To attain this purpose, among the promising
non-destructive/non-hazardous techniques that are performed for the
interrogation of the nuclear materials is the muon tomography where the
target materials are discriminated by the interplay between the atomic
number, the material density, and the material thickness on the basis of
the scattering angle and the absorption in the course of the muon
propagation within the target volume. In this study, we employ the Monte
Carlo simulations by using the GEANT4 code to demonstrate the capability
of muon tomography based on the dual-parameter analysis in the
examination of the nuclear waste barrels. Our current hodoscope setup
consists of three top and three bottom plastic scintillators made of
polyvinyl toluene with the thickness of 0.4 cm, and the composite target
material is a cylindrical nuclear waste drum with the height of 96 cm
and the radius of 29.6 cm where the outermost layer is stainless steel
with the lateral thickness of 3.2 cm and the filling material is
ordinary concrete that encapsulates the nuclear materials of dimensions
20×20×20 cm3. By simulating with a narrow planar muon beam of 1×1 cm 2
over the uniform energy interval between 0.1 and 8 GeV, we determine the
variation of the average scattering angle together with the standard
deviation by utilizing a 0.5-GeV bin length, the counts of the
scattering angle by using a 1-mrad step, and the number of the
absorption events for the five prevalent nuclear materials starting from
cobalt and ending in plutonium. Via the duo-parametric analysis that is
founded on the scattering angle as well as the absorption in the present
study, we show that the presence of the nuclear materials in the waste
barrels is numerically visible in comparison with the concrete-filled
waste drum without any nuclear material, and the muon tomography is
capable of distinguishing these nuclear materials by coupling the
information about the scattering angle and the number of absorption in
the cases where one of these two parameters yields strong similarity for
certain nuclear materials.