Fully consistent, full core, three-dimensional, deterministic neutron transport simulations using the orthogonal mesh code Denovo were run on the massively parallel computing architecture Jaguar XT5. Using energy and spatial parallelization schemes, Denovo was able to efficiently scale to more than 160 000 processors. Cell-homogenized cross sections were used with step characteristics, linear discontinuous finite element, and trilinear discontinuous finite element spatial methods. It was determined that using the finite element methods gave considerably more accurate eigenvalue solutions for large-aspect ratio meshes than using step characteristics.