Numerical simulation of QUENCH-10, -16 integral experiments for oxidation of zirconium fuel rod claddings in a steam-air environment

The paper presents the results of SOCRAT-V1/V2 code simulation of QUENCH-10, -16 experiments for oxidation of zirconium fuel rod claddings in a steam-air environment. The simulation results are consistent with experimental data at the stages of heating, preliminary oxidation, and cooling. However, at the flooding stage after oxygen starvation, the calculated mass of released hydrogen is lower than measured one. The differences are due to the fact that simulation does not take into account the formation of zirconium nitrides at the stage of oxygen starvation and their effect on the oxidation process. Zirconium nitride in the zirconium oxide layer significantly intensifies the diffusion of oxygen, which, in turn, leads to an abrupt increase in the mass of hydrogen at the flooding stage.