International Topical Meeting on Nuclear Research Applications and Utilization of Accelerators
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AP/DM-02
Modeling of Cascades and Sub-Cascade Formation in Materials Irradiated by Fast A.I. Ryazanov and E.A. Semenov Russian Research Center “Kurchatov Institute”, Moscow, Russian Federation Corresponding Author: ryazanoff@comail.ru A new theoretical model is developed and used for the investigation of cascades and sub-cascade formation in fission and fusion structural materials under fast neutron energy spectra corresponding to the fission and fusion reactors and fast charged particle irradiations. The developed model is based on the analytical consideration of elastic collisions between displaced moving atoms into atomic cascades produced by a primary knock atom (PKA) with the some kinetic energy getting from fast charged particles and fast neutron irradiations. The criterion of sub-cascade formation is based on the comparison of two calculated values: mean distance between two consequent PKA collisions and the size of sub-cascade produced by PKA. The Thomas-Fermi interaction potential is used for the describing of elastic collisions between moving atoms. The suggested model takes into account electronic losses of moving atoms between elastic collisions of them during the scattering process. The analytical relations for the most important characteristics of sub-cascade are determined including the average number of sub-cascades per one PKA in the dependence on PKA energy, the distance between sub-cascades and the average sub-cascade size as a function of PKA energy. The developed model allows determining the size distribution function in the dependence on PKA energy. Based on the developed model the numerical calculations for main characteristics of sub-cascades in different materials are performed using the neutron flux and PKA energy spectra for fusion reactors: ITER, DEMO, IFMIF-Source and fission High Flux Irradiation Reactor (HFIR). So the total numbers of sub-cascades, distribution functions of sub-cascades in dependence on their sizes and generation rate of sub-cascades for different fission and fusion structural materials: Fe, V, W, Be, Cu and C are calculated for these fission and fusion irradiation conditions. The obtained numerical results for main characteristics of cascades and sub-cascade formation under fission and fusion irradiation conditions in these materials are compared with the same results obtained in these materials using different types of fast charged particle irradiations on cyclotron of RRC “Kurchatov Institute”.
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