  Cosmic ray muons passing through matter lose energy from inelastic collisions
with electrons and are deflected from nuclei due to multiple Coulomb
scattering. The strong dependence of scattering on atomic number Z and the
recent developments on position sensitive muon detectors indicate that multiple
Coulomb scattering could be an excellent candidate for spent nuclear fuel
imaging. Muons present significant advantages over existing monitoring and
imaging techniques and can play a central role in monitoring nuclear waste and
spent nuclear fuel stored in dense well shielded containers. The main purpose
of this paper is to investigate the applicability of multiple Coulomb
scattering for imaging of spent nuclear fuel dry casks stored within vertical
and horizontal commercial storage dry casks. Calculations of muon scattering
were performed for various scenarios, including vertical and horizontal fully
loaded dry casks, half loaded dry casks, dry casks with one row of fuel
assemblies missing, dry casks with one fuel assembly missing and empty dry
casks. Various detector sizes (1.2 m x 1.2 m, 2.4 m x 2.4 m and 3.6 m x 3.6 m)
and number of muons ($10^{5}, 5\cdot10^{5}, 10^{6}$ and $10^{7}$) were used to
assess the effect on image resolution. The Point-of-Closest-Approach (PoCA)
algorithm was used for the reconstruction of the stored contents. The results
demonstrate that multiple Coulomb scattering can be used to successfully
reconstruct the dry cask contents and allow identification of all scenarios
with the exception of one fuel assembly missing. In this case, an indication
exists that a fuel assembly is not present; however the resolution of the
imaging algorithm was not enough to identify exact location.
