Radiation-damage research started with the installation of the first nuclear reactors in the United States. In 1946 Wigner pointed out that energetic neutrons would displace atoms from their regular lattice sites and thus change the properties of irradiated materials—a prediction that was soon confirmed experimentally. Most of these changes are unfavorable for the performance of materials, justifying the influence of radiation being referred to as “radiation damage.”

Since radiation-induced materials degradation can have a drastic impact on the safe and economic operation of present fission reactors and, probably even more, on future fusion reactors, radiation-damage research comprised a large part of the research-and-development programs for nuclear materials. As a result of this effort, a broad database is now available, and materials have been developed that fulfill practically all requirements being encountered in present nuclear technology.

Besides this applied work, extensive fundamental research on radiation effects has been carried out because physicists soon recognized that bombardment with energetic particles offered a unique method to create controlled populations of defects in solids. Whereas the cross-linking between basic and applied research was rather weak in the early stages, a convergence of the two branches has been clearly noticeable during the last decade. This welcome development occurred for a variety of reasons. Examples are the need to employ simulation irradiations in cases where no prototypic devices exist (fusion reactors, high-power spallation neutron sources) and the increasing application of ion-beam techniques in microelectronics, thin-film technology, and metallurgy where the damage produced by the implanted ions needs clarification.