Safe operation:

For safe operation, the total deformation because creep must be well below the strain at that failure occurs. This could be done through staying well below the creep limit, that is described as the stress to that a material could be subjected without the creep exceeding a specified amount after a provided time at the operating temperature (for instance, a creep rate of 0.01 in 100,000 hours at operating temperature). On the temperature at that high-pressure vessels and piping operate, the creep limit commonly does not pose a limitation. Alternatively, it might be a drawback in links with fuel element cladding. Zircaloy has a low creep limit, and zircaloy creep is a major consideration in fuel element design. For instance, a zircaloy cladding of fuel components in PWRs has suffered partial collapse caused through creep under the influence of high temperature and a high pressure load. As same, creep is a consideration at the temperatures which stainless-steel cladding encounters in gas-cooled reactors and fast reactors where the stainless- steel cladding temperature might exceed 540ºC.