The motivation for the proposed experimental program is the recent interest throughout the world on revisiting and revising the existing thermal neutron scattering data in the cross section libraries such as ENDF/B (US), JEFF (OCDE/NEA), JENDL (Japan), CINDL (China) and BROND (Russia). Many questions emerge from the Working Party on International Nuclear Data Evaluation Co-operation (WPEC) of the NEA data bank related to the impact of the thermal scattering data on criticality benchmarks. Investigation and production of covariance matrices are also key issues for light and heavy water reactors.This proposal is part of a multi-year program plan on actinides. First, we wish to extract S(alpha,beta) tables from the double-differential neutron cross sections of UO2 as a function of the temperature. The temperatures of interest range from room temperature to Hot Full Power conditions (T=1000 K). Final S(alpha,beta) tables will be introduced in evaluated nuclear data libraries and tested on critical benchmarks carried out in the zero-power reactor EOLE located at the CEA of Cadarache and on Power reactor benchmarks.