Benchmark Critical Experiments on High-Enriched Uranyl Nitrate Solution Systems

Seventy-six benchmark critical conditions are reported. Both material and geometry properties are so well determined as to reduce greatly any contribution to a theoretical/experimental discrepancy attributable to the experiment. The program uses uranyl nitrate solution with the uranium enriched to 93.17% ²³⁵U. The concentration ranges from 54.89 to 369.96 g U/ℓ Unreflected experiments are reported, as well as measurements within thick-walled cubical reflector shells composed of such common materials as concrete and plastic. For experiments using a single tank, the diameter of the tank ranged from 27.88 to 50.69 cm, and arrays of up to 16 cylinders have containers of two diameters: 16.12 and 21.12 cm. Containers composed of aluminum or stainless steel are studied. For all these parameters, the critical heights range from 17.13 to 110.20 cm.