SHIELDING STUDIES ON SALT SLABS, GADOLINIUM, AND WATER

A lid-tank shielding facility, simular to the one in operation at Oak Ridge, has been constructed and is in operation at Battelle. This facility was descnibed in BMI-1291. The fast-neutron and gamma dose rates and thermalneutron fluxes were mapped in a symmetry plane of the shielding tank. Fast-neutron and gamma dose rates were raeasured behind a series of shielding plugs along a line in the water perpendicular to the fission-plate center. The plug materials included aluminum, iron, lead, titanium, and gadolinium. In order to use small- diameter plugs the effective diameter of the fission plate was reduced for these experiments by placing an iris between the thermal column and the flssion plate. The purpose of the test was to determine the removal cross section of gadolinium by comparison with other materials, using a small amount of gadolinium. The removal cross section for gadolinium is about the same as for lead. Experiments were conducted on ordinary and enriched LiH slabs 4 to 32 in. thick. Fast- neutron and gamma dose rates in addition to thermalneutron fluxes were measured on the water center line behind the slabs. (auth)