Skip to Main Content
Your organization might have access to this article on the publisher's site. To check, click on this link:http://dx.doi.org/+10.1063/1.1702267
The diffusion equation for thermal neutrons in a pile with finite sides and having a three‐dimensional lattice structure of fissionable material and moderator is solved to the first three orders by an expansion in spherical harmonics. This solution is used to calculate the difference in thermal utilizations of a pile of infinite extent and one with finite sides. From this difference is calculated an accurate expression, Eq. (24), for the diffusion length in a pile having a lattice structure. This expression is compared with the usual simplified equation for the diffusion length. The leakage of neutrons from a pile is also obtained from this calculation.