Investigations related to the generation of reaction products in the target of accelerator driven systems for nuclear waste incineration

For many years, many countries have been considering accelerator transmutation of waste (ATW) as a solution for processing the nuclear waste as well as a mean of generating power with a subcritical system. Several research groups are now working on this topic all over the world and this has already led to the proposal of accelerator driven systems (ADS) concepts. The main objective of these systems is the incineration of long-lived isotopes from the spent fuel of actual and future reactors. At the Institut fuer Reaktorsicherheit (IRS) of the Forschungszentrum Karlsruhe, some of the actual activities are focussed on the near future developments of ADS. In this scope, IRS is participating within the 5th European Community Framework Program to MEGAPIE, MUSE and XADS projects. Development and experimental qualification of theoretical tools for core design and safety evaluations of accelerator driven sub-critical systems are important current topics investigated at IRS. In particular, for the analysis of accelerator driven systems (ADS), the coupling of a proton source with a sub-critical reactor system may be investigated with the current version of MCNPX, a code developed at LANL and for which IRS is beta-tester. The present work was done in the scope of this beta-testing activity. We analysed the applied theoretical models for investigations of spallation physics as well as their application in the code MCNPX. We validated our application of MCNPX by making comparisons with available benchmark results and with experimental data for neutron yields per proton, for thin target cross-section measurements and for a thick target activation experiment. We also calculated several parameters related to important reaction products for the MEGAPIE project. (orig.)