Neutronic design studies for the Spallation Neutron Source

Neutronics analyses are now in progress to support initial selection of tar get system design features, materials, geometry, and component sizes for th e proposed Spallation Neutron Source. Calculations have been performed to d etermine the neutron, proton, heavy-ion, and gamma-ray flux spectra as a fu nction of time, energy, and space for the major components of the target st ation (target, moderators, reflectors, etc.). These analyses have also been performed to establish an initial set of performance characteristics for t he neutron source. The methodology, reference performance characteristics, and results of initial optimization studies involving moderator poison plat e location, target material performance, reflector performance, moderator p osition, and premoderator performance for the target system are presented.