Heating and Radiation Damage

Nuclear heating results from the slowing down of energetic charged particles produced in nuclear reactions, including the recoil nucleus from scattering reactions. It is a very important quantity. Sometimes it is the product being sold (as in power reactors), and sometimes it is a damaging corollary of the nuclear reactions (as in melting of important structural elements). The HEATR module of NJOY can be used to compute estimates of energy-deposition cross sections for neutrons that can be combined with calculations of neutron fluxes in nuclear systems to compute the neutronic contributions to nuclear heating. The heating due to the photon flux in a nuclear system is usually even more important; it is computed in the GAMINR module.

The same energetic charged particles and recoil nuclei that lead to heating can also cause damage to the crystalline structure of the materials that they pass through. An important case of this is the embrittlement of power reactor containment vessels that is one of the main limiting factors in the useful life of a commercial reactor. HEATR computes the damage-production energy, which can be correlated to macroscopic damage, such as tensile strength, ductility, or resistivity, through phenomenological factors like DPA (displacements per atom).


23 January 2013 T-2 Nuclear Information Service ryxm@lanl.gov