(a) Zirconium alloys are used a cladding (surrounding) material for nuclear fuels due to their near transparency to neutrons. Calculate the diffusion coefficient for hydrogen in high purity zirconium at 250 °C. (b) If it takes 1 year to diffuse a certain amount of oxygen into zirconium at 250 °C, how long will it take for the same amount of diffusion to occur at 500 °C? Some information: Qd = 11.4 kcal/mol Do = 1.09 cm2 /sec Zr and H both have the HCP structure. The diffusion mechanism is interstitial.