IDTEQRAL VADIDATIOD OI TED J2?2 HAJOB ACTIDIDEB FOR THERMAL WUl’ROll REACTOR8

Gif sur Yvette Cedex. France The neutron and nuclear data which are needed by reactor physicists to per-form core calculations are brought together in the evaluated neutron data files. Since several years the integral experiments are used to validate the nuclear data of these files. In these types of experiments, we measure synthetic parameters such as buckling or reaction rates which characterize the cell and the neutron spectrum. In the case of very simple geometries and asymptotic spectrum, such as uniform lattices or homogeneous media. the difference between the computed values of the synthetic parameters and the measured ones can be attributed to the inaccuracy of the neutron data. From these differences we can deduce informations about the nuclear data. It is the tendency research method. This method was used for the validation of %“,ma8~ ” ad 239p actinides of the second version of the Joint evaluated file: u. Sixty six buckling measurements were used for this qualification. The results are compared with recent recommended values