The effective neutron multiplication factor (keff) of a fissile system is a function of space and time f(x,y,z,t), where (x,y,z) are the coordinates of the reference point in space and t is time. Scientific proof of the time-dependence of the neutron multiplication factor of a fissile system was published in 2017 [1]); as such, this research will focus on determining the spatial dependence of the neutron multiplication factor of a fissile system using spent fuel casks.