Achievements and deficiencies of nuclear models used for the design of spallation sources

High-energy transport codes are used in a large number of domains as spallation neutron sources or ADS design, space or medical applications. In these codes, nuclear models describing spallation reactions generate the necessary elementary cross-sections and characteristics of all the reaction products. During the last years, new high-quality experimental data have been collected leading to the development of more reliable spallation models, as the INCL4-ABLA combination of intranuclear cascade and de-excitation models, now available in MCNPX. However, remaining deficiencies have been identified, which can be of important consequences for applications, for instance in the prediction of damage. They generally originate from not well understood physics mechanisms. To solve these problems more constraining experiments are now being carried out, which allow a deeper understanding of the reaction mechanisms, in particular for the de-excitation stage. Recent improvements of INCL4 are presented. Impact for applications is discussed. (authors)