<p> Ferritic- Martensitic (F/M) alloys have been used in reactors as cladding steels, wrapper steels. They have Good creep strength, longer lifetimes, less corrosion Powder Metallurgy Hot Isostatic Pressing (PM- HIP) alloys have been suggested as an alternative to be able to improve reactor safety. Gaining a better understanding on how PM-HIP microstructures change under irradiation could make them more viable for widespread use in reactors   </p>