The neutron physics of concrete reflectors

It has long been known that concrete reflection can be an important factor in determining the critical state of any fissile system, single unit or storage array. Since there can be a large variation in the chemical makeup of concrete, mass-limit reduction factors are necessarily conservative, and may lead to a very uneconomical storage arrangement. This study was undertaken to clarify the importance of the various concrete constituents and to determine some general guidance as to the magnitude of the reactivity effects for the more likely fissile material storage conditions