Interaction of subcritical reactors

Abstract

When determining the nuclear safety of systems containing fissionable materials, the interaction of all the components must be taken into consideration; however, this is often impossible to do in the case of subcritical systems. Approximations must therefore be used for estimating the safety margin of the interacting system. In order to facilitate the problem, an attempt was made to replace the given subcritical array consisting of materials possessing given nuclear properties and geometric parameters by a reactor that is equivalent to the first one with regard to the buckling, but has different nuclear properties; equations were obtained for determining the equivalent geometrical dimensions. The equations derived were experimentally verified on subcritical arrays containing cylinders and square parallelipipeds, made of stainless steel containers with a wallthickness of 1.5 to 2 mm and radii or sides of 30 cm, filled with an aqueous solution of 90%-enriched /sup 235/Uo/sub 2/(NO/sub 3/)sub Similar systems were also built with 6-liter capacity glass cylinders with 0.5-cm thick walls. Comparison of the experimental and theoretical values indicated that the latter cortain a suitable safety margin and therefore may be used for evaluating the safety of an interacting system; this was proved by recalculating the data of E.more » Woodcock and U. Paxton (Progr. Nucl. Energy Series Vol. 4, 213 (1961)) concerning a system of U spheres. (TTT)« less