Development of multi-group neutron activation cross-section library for decommissioning of nuclear facilities

Okumura, Keisuke ; Kojima, Kensuke; Tanaka, Kenichi*

In the safety assessment concerning disposal of radioactive wastes generated in the decommissioning of nuclear facilities, it is necessary to evaluate the radionuclide inventory produced by the activation of structured materials. For this purpose, we have to pay much attention to the activation of many impurities irradiated in various neutron spectra depending on their positions and materials. Therefore, accurate activation cross-section data are necessary for many nuclides and reactions. A new multi-group neutron activation cross-section library (MAXS) was developed based on the recent nuclear data JENDL-4.0 and JEFF-3.0/A to apply it to the activation calculations for the decommissioning of nuclear facilities. The library contains cross-sections and isomeric ratios for many reactions such as (n,), (n,f), (n,2n), (n,3n), (n,p), (n,), (n,d), (n,t), (n,n), (n,np), and so on, for 779 nuclides, in the 199-energy group structure of VITAMIN-B6.