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The nuclear data processing code NECP-Atlas, developed at Xi’an Jiaotong University, has various functions to process the evaluated nuclear data to generate the applied nuclear data library for the nuclear reactor designs. In this paper, the photonrelated data generation capacities were developed in NECPAtlas, including the photon production cross sections and photon irradiation cross sections. In the conventional nuclear data processing code such as NJOY, only the production cross section for the prompt photon released with the neutroninduced reactions, and the photonatom reaction cross section can be produced, while the delayed photon released by the fission products is ignored regardless of its large contribution for the heating of the regions without fissionable materials such as control and reflector assemblies in fast neuron reactors. In this paper, the capacity for the generation of the production cross section for the delayed photon was developed in NECPAtlas. Besides, in the conventional nuclear data processing code, only the neutron irradiation damage cross section can be generated, while in the practical reactors, electron and positron also cause significant irradiation damage. The photonatom reactions, including Compton scattering, pair production and photoelectric effect, emit electron and positron. Therefore, the photon can also cause irradiation damage. To satisfy the demands from various application aspects, the capacity for the calculation of the photon irradiation damage cross sections was also developed in NECPAtlas. Meanwhile, the electron and positron irradiation damage cross section can also be produced, because it is the basis for the calculation of photon irradiation damage cross section. The delayed photon production cross sections were tested on the EBRⅡ fast reactor, and the results were compared with the library of the ERANOS which includes the production cross section of delayed photon. The difference of photon heating calculated based on the two libraries respectively from NECPAtlas and ERANOS is less than 0.93%, which means the correctness of the delayed photon data produced by NECPAtlas. Besides, the numerical results show that if the delayed photon is ignored, the difference of photon heating for the control assembly and reflector assembly can reach 3258% and 2041%, compared with the results of considering the delayed photon. The electron and positron displacement damage cross sections of Fe and Au calculated by NECPAtlas were verified with the results published by Oka Ridge National Laboratory, and the photon displacement cross sections calculated by NECPAtlas were verified with results reported by other researches. The numerical results show good agreement with the reference results. |
