Max Phase Materials for Nuclear Applications

This chapter discusses how MAX phases combine unique mechanical and thermal properties with good corrosion resistance and promising radiation tolerance. Their unique combination of properties makes some of the MAX phases attractive for harsh service conditions such as those established in the core of a nuclear reactor system. More specifically, the cladding tubes containing the fuel pellets are subjected to elevated temperatures and high neutron irradiation doses while being exposed to a usually corrosive primary coolant. The chapter also examines the influence of the chemical starting composition on the final phase assembly of the hot pressed ceramics, revealing that selecting the appropriate Al and C contents in the starting powder mixture is crucial. Phase‐pure ceramics were not obtained under the investigated conditions. One of the major challenges in the development of lead‐cooled fast reactors (Gen‐IV LFRs) is the inherent corrosiveness of the heavy liquid metal coolant for most structural and cladding steels. Undesirable liquid metal corrosion effects degrade all stainless steels exposed to liquid lead (Pb) and lead‐bismuth eutectic (LBE) due to the dissolution of steel alloying elements (Ni, Mn, Cr, Fe) in the liquid metal, which becomes severe at high temperatures and low oxygen contents in the liquid metal coolant.