Fuel cladding is one of the most critical components of nuclear reactors; so it is important to improve our understanding of various properties and behaviors of the cladding under different conditions approximating the nuclear reactor environment. Moreover, the efficiency of energy production, in addition to safety concerns, has resulted in progressive improvement of nuclear reactors design from Generation I to Generation IV. To complement this progressive trend, materials used for fuel cladding need to be improved or new materials should be developed. In this thesis, I address problems in the improvement of present fuel cladding and also investigate fuel cladding materials to be used in future Generation IV nuclear reactors.