Complex sentence: In addition zircaloy can react with uranium dioxide to form zirconium dioxide and uranium metal, this exothermic reaction together with the reaction of boron carbide with stainless steel can release additional heat energy thus contributing to the overheating of a reactor.
Split into simpler sentences: In addition zircaloy can react with uranium dioxide to form zirconium dioxide and uranium metal. This exothermic reaction together with the reaction of boron carbide with stainless steel can release additional heat energy thus contributing to the overheating of a reactor.