Prediction of radiation damage in structural materials outside the reactor core

Computer studies were done to improve the prediction of radiation damage outside the reactor core for a PWR and a fast reactor. The aim was to show, how measurements of the neutron fluence and calculations of the energy spectra could be combined best. Outside the core there is a strong local variation of the neutron fluence accompanied by appreciable changes in neutron energy spectrum. With one- and two dimensional Ssub(N) calculations the correlation was determined between surveillance samples at accelerated positions near the core and the expected damage in the pressure vessel. Displacement cross sections were calculated for the important nuclides in steel from ENDF/BIV data. The neutron flux spectra were weighted appropriately to get the displacement rates as a function of neutron energy. With this spectral quantity correlations are shown and possible uncertainties are discussed for both reactor types. Our results show, that calculations of displacement cross section and neutron flux spectra need high computational effort, if errors of 30% in the displacement rate sh