Polyethylene-Reflected Arrays of HEU(93.2) Metal Units Separated by Vermiculite

This benchmark details the results of an experiment performed in the early 1970s as part of a series testing critical configurations in three dimensional arrays. For this experiment, cylinders of 93.2% enriched uranium metal were arranged in a 2 x 2 x 2 array inside of a polyethylene reflector. Layers of vermiculite of varying heights were surrounding each cylinder to achieve criticality variations. A total of four experimental configurations were tested by D.W. Magnuson, and detailed in his experimental report 'Critical Three-Dimensional Arrays of Neutron Interacting Units: Part IV. Arrays of U(93.2) Metal Reflected by Concrete and Arrays Separated by Vermiculite and Reflected by Polyethylene.' The benchmark HEU-MET-FAST054 is closely related; the results of both experiments are discussed in the same report (Ref. 1) Closely related work has been recorded in HEU-MET-FAST-053, which is a benchmark evaluation of a different series of three dimensional array experiments with four different moderator materials. HEU-MET-FAST-023 and HEU-MET-FAST-026 are also related because they utilize the same metal cylinders as these experiments.