We have measured solubility constants for hydrogen and deuterium in the Zr–Al alloy to be: K H = exp [11.1(5)−16900(600)/T] [Torr/(Torr⋅1/g)2] and K D = exp [12.2(8)−16800(600)/T] [Torr/(Torr⋅1/g)2], respectively, where K is defined implicitly by P = K q 2 with P the equilibrium pressure (in Torr) and q the bulk concentration (in Torr⋅l/g). These values, in conjunction with a model for the solubility, predict that the constant for tritium, K T ∠4K H. Consequently, the regeneration of tritium will be faster by a factor of 4 over that for hydrogen at the same temperature, or the tritium regeneration temperature can be reduced∠50 K compared to hydrogen for the same regeneration time.