Transient hydride fuel behavior in LWRs

The transient response of a uranium zirconium hydride (U0.31ZrH1.6) fuel element to conditions typical of a light water reactor reactivity insertion accident has been studied. Hydrogen diffusion within the fuel is treated as a function of the time-dependent temperature profile. Temperature and hydrogen concentration dependence of thermal properties of the fuel is also considered. The set of coupled equations describing the transient conduction of heat and diffusion of hydrogen are solved with a Crank–Nicolson discretization scheme for heat diffusion and an explicit Euler scheme for hydrogen diffusion.