Compilation of criticality data involving thorium or 233U and light water moderation

Abstract

The literature has been searched for criticality data for light water moderated systems which contain thorium or 233 U, and data found are compiled herein. They are from critical experiments, extrapolations, and exponential experiments performed with homogeneous solutions and metal spheres of 233 U; with lattices of fuel rods containing highly enriched 235 U02-Th0 2 and 233 U02-Th0 2 ; and with arrays of cylinders of 233 U solutions. The extent of existing criticality data has been compared with that necessary to implement a thorium-based fuel cycle. No experiments have been performed with ~ solutions containing thorium. Neither do data exist for homogeneous 233 U systems with H/U < 34, except for solid metal systems. Arrays of solution cylinders up to 3 x 3 x 3 have been studied. Data for solutions containing fixed or soluble poisons are very limited. All critical lattices using 233 U02 Th0 2 fuels (LWBR program) were zoned radially, and in most cases axially also. Only lattice experiments using 235 U02-Th0 2 fuels have been performed using a single fuel rod type. Critical lattices of 235 U02-Th0 2 rods pOisoned with boron have been measured, but only exponential experiments have been performed using boron-. poisoned lattices of 233 U02-Th0 2 rods. No criticality data exist for denatured fuels (containing significant amounts of 238 U) in either solution or lattice configurations.

Neutronic experiment planning for the Fuels Refabrication and Development Program

“…Criticality data involving thorium or 233U and light water moderator have been compiled (2) in support of an earlier program, the Thorium Fuel Cycle Technology (TFCT) Program. Review of these data indicates that the only critical lattices of 233 U02 -Th0 2 fuel rods ever measured were "seed and blanket" cores assembled for the LWBR program.…”