a$)$ For a region on Zircaloy$-4$ cladding in which a $40-m$ oxide layer was formed, and the

outside cladding temperature is $340C,$ determine whether at that stage of corrosion a

hydride rim can form and, if it does, determine its thickness, assuming the hydrogen

content in the rim is $3,000wppm$ and all the hydrogen in the cladding is in the rim at that

point. Consider that the hydrogen pickup fraction is $18\%.$

b$)$ In forming the $40m$ oxide layer above, if the corrosion follows linear kinetics at $340C$

in Zircaloy$-4,$ with a transition at $1\mathrm{.}84m$ occurring at $1\mathrm{.}5$ years calculate the oxide thickness

at which the hydride rim first forms, assuming the cladding thickness is constant and equal to

$600m.$