Boron carbide: Steam reactions with cesium hydroxide and with cesium iodide at 1270K in an Inconel 600 system

Three laboratory scale tests examined the effect of boron carbide, used for the control of some nuclear power reactors, on reactor accident conditions. The tests, conducted in steam at 12700K in an Inconel 600 system, examined the boron carbide-steam system and then that system with an addition of cesium hydroxide or cesium iodide vapor. Extensive reaction was demonstrated between the boron carbide and steam to produce B2O3 and boric acids in a two step kinetic process. Average rates of production for the oxide and acids were calculated for the three tests. These rates are functions of time, temperature, B4C geometry, and partial pressure of the steam and the boric acid. Significant reactions were observed between the boric oxide formed on the B4C and both the CsOH vapor and the CsI vapor, dissociating the cesium and iodine in the latter case. The cesium reaction product in both cases was probably CsBO2, with the iodine forming HI. Surface reaction rate constants were estimated for the CsOH and the CsI reactions