43. Irradiation Damage in Nuclear Power Plants

The chapter gives an introduction into the main processes occurring in metals and alloys under neutron irradiation. Displacement damage, phase reactions, swelling, irradiation creep, and transmutation are the main physical effects changing mechanical properties and microstructure of materials used in nuclear power plants. As results radiation hardening/embrittlement, enhanced stress corrosion cracking, changes in geometry, degradation of creep properties, and other damage can occur. Consequences of such material degradation are discussed for current nuclear plants where a 50-year operation experience exists. Advanced, future nuclear plants are expected to consist also almost exclusively of metals and alloys, and they are expected to undergo in principle the same types of damage. However, changes in other operational parameters (higher temperatures, fast neutrons, other coolants) might change also the degree of radiation damage (e.g., thermal creep in addition to radiation creep). Advanced modeling and testing techniques can be considered as a tool to balance the missing long-term experience with next-generation nuclear plants.