Prediction of the amount of hydrogen generated during a molten fuel-coolant interaction

The model in development predicts the production of hydrogen as a result of a molten fuel-coolant interaction in a water-cooled nuclear reactor. It has three interrelated modules: kinetics, heat transfer, and hydrodynamics. Second and third order rates are assumed for uranium and aluminum respectively, the chosen fuel and cladding. Heat is generated by chemical reaction and radioactive decay and dissipated through radiation and convection. Dispersion of the melt as it descends through a pool of water is modeled using the Weber number, which ratios the shear forces due to the relative velocities of the fluid and the metal to the surface tension of the metal. Hydrogen generation is sensitive to the initial melt temperature and to the assumptions made about the modes of heat transfer, but not the the impact velocity of the metal particle. The hydrogen generation per unit mass of uranium generally increases as the initial particle size decreases suggesting that the kinetics rather than the heat transfer controls the energy balance