Temperature Dependence of the Multiplication Factor in LWR Lattices. Final Report

摘要

The temperature dependence of the neutron multiplication in typical BWR and PWR unit cells is determined as a function of fuel depletion when the fuel temperature is changed from 800 exp 0 K to 1200 exp 0 K. The cross section changes with temperature of the principal isotopes of Uranium and Plutonium, and of some fission products, are taken into account simultaneously in the lattice analysis by means of very detailed resonance profile tabulations in the resolved resonance region of each nuclide. In addition the small temperature dependence of non 1/v absorption cross sections is included in the thermal multigroup library, as well as the UO sub 2 group to group scattering kernel as a function of temperature in the thermal energy region. The report includes details relating to the temperature dependent cross section libraries, broad cross sections and fluxes, together with the calculational methods which make use of discrete ordinate integral transport calculations at epithermal energies and multigroup methods in the other energy ranges.