Effect of fraction of voids in the nuclear fuel burned for a 10 X 10 assembly of a BWR

A major source of uncertainty in BWR reactor physics is associated with the properties of moderation and coolant bypass regions with a very significant impact on nuclear parameters such as: the finite multiplication factor (k∞), area migration of neutrons (M2) and the void coefficient of reactivity (aν). In this work, we assess the effect caused by the presence of voids in the moderator during the burning of fuel in a fuel assembly type SVEA-96 for a BWR; the codes uses as a tool were INTERPIN-3 and CASMO-4. The geometry SVEA-96 is characterized by an assembly subdivided in four sub-bundles, through an internal bypass cross-shaped gap that allows a more uniform distribution of the moderator, providing a better distribution in the neutrons flux, and thus provide a better distribution of energy and burned. This study was conducted for a wide range of void fractions, from 0% (pure liquid) to 100% (pure steam) and covered: 1) The effect caused by the presence of voids during the burning of nuclear fuel 2) the effects of the structure of energy groups including libraries of cross sections based on ENDF/B-4, and 3) the impact of the presence of control rod. The burning range is from 0 G Wd/Mt to 50 G Wd/Mt. (Author)