Deuterized Closely Packed Seed Blanket Breeder. Final Report for the Period 1 December 1976 - 30 November 1978

摘要

Nuclear code developments, improvements and bench marking over a wide range of parameters in the subject area has been achieved. In particular the WIMS-D code was verified favourably in the area of tight lattices; also good comparisons were obtained between 9 energy groups and 69. Similar developments are presented for burn-up calculations, determination of temperature coefficients and two dimensional transport calculation. Studies were made on uniform lattices for a wide range of fuel compositions and various moderator to fuel atom ratios. It was found that for tight lattices, .5 to 1.0 moderator to fuel ratio, good initial conversion ratios (ICR) in the range of 1.2 or more were obtained with Pu exp 239 fuel, the tighter the lattice the better the ICR. For U-235, breeding can be obtained only for extremely tight lattices, moderator to fuel ratio below 0.6. A ref. design was chosen (see C) accordingly. The use of realistic plutonium compositions, corresponding to discharge from light water reactors, was found to improve breeding potential, increasing ICR by a range of ten percent or more. For the core designs considered Geometry Control was found to be far superior in breeding performance to Spectral Shift Control or to control by conventional absorbing rods. The following parameters are recommended for a reference core design, suitable for 1000MWe: Initial fuel loading Pu-239 and Pu-241 and tailings with 0.3% U-235; 42 seed/blanket unit assemblies, geometry controlled by moving seed. Seed power density: about 300 W/CC; Coolant/moderator composition: 80% D sub 2 O, 20% H sub 2 O. (Atomindex citation 11:525933)