Method and database for obtaining solid and liquid fluorine salt thermal neutron scattering database

Abstract

The method and the database for obtaining the thermal neutron scattering database of solid and liquid fluorine salts, the method steps are: 1. For solid fluoride salt crystals and liquid fluoride salt solutions, use the lattice dynamics program based on the principle of first quantum mechanics to calculate Its phonon spectrum distribution; In addition, for liquid fluoride salt solution, use the statistical physics method based on molecular dynamics to calculate the diffusion coefficient of each fluoride salt ion; 2, the phonon spectrum distribution and diffusion coefficient obtained in step 1 are provided to The nuclear data processing program NJOY can obtain the thermal neutron scattering data of solid and liquid fluorine salts; 3. According to different application purposes, the corresponding nuclear database index file is provided, and the index file and the thermal neutron scattering data obtained in step 2 form a complete set The database of thermal neutron scattering; the present invention also discloses the database obtained by providing the method; it fills the gap in the field of thermal neutron scattering database production for multi-group transport and subgroup resonance calculation of solid fluoride salt crystals and liquid fluoride salt solutions in the world blank.

Description

technical field [0001] The invention relates to the fields of nuclear data processing and nuclear reactor physical calculation, in particular to a method for obtaining a solid and liquid fluorine salt thermal neutron scattering database and the obtained database. Background technique [0002] The scattering process of thermal neutrons and core materials will be affected by the bound state of the core material target nucleus. During the scattering process, thermal neutrons may transfer energy to the target nucleus to make it excited, and there is also a certain probability that the energy will be obtained due to the vibration of the target nucleus. It is to consider the thermal neutron scattering phenomenon of the bound state of the target nucleus. Thermal neutron scattering will obviously affect the thermal neutron energy spectrum and the fission reaction rate of fission nuclei, thus indirectly affecting the safety characteristics of nuclear reactors. Fluoride salt (chemica...

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Problems solved by technology

Thermal neutron scattering will obviously affect the thermal neutron energy spectrum and the fission reaction rate of fission nuclei, thus indirectly affecting the safety characteristics of nuclear reactors

Fluoride salt (chemical formula is LiF-BeF 2 , NaF-ZrF 4 、LiF-NaF-ZrF 4 、LiF-NaF-BeF 2 , NaF-NaBF 4 Such as fluorine-containing salt materials) have been or will become moderators or coolants of nuclear reactors such as molten salt reactors and fluorine-salt cooled pebble bed reactors. However, the latest international ENDF (Evaluated Nuclear DataFiles, ENDF, the same below) format The evaluation basic nuclear database such as the US ENDF / B-VII.1 database only includes hydrogen in light water, deuterium in heavy water, parahydrogen, orthohydrogen, paradeuterium, orthotritium, solid methane, liquid methane, graphite, metal beryllium , beryllium in beryllium oxide, oxygen in beryllium oxide, silicon dioxide, uranium in uranium dioxide, oxygen in uranium dioxide, hydrogen in zirconium hydride, zirconium in zirconium hydride, polyethylene, benzene, iron, aluminum, etc. Thermal neutron scattering database of 21 materials; European JEFF3.1.1 database only includes water, heavy water, graphite, hydrogen in zirconium hydride, hydrogen in calcium hydride, calcium in calcium hydride, metal beryllium, magnesium, polyethylene, etc. The thermal neutron scattering database of 9 materials; the Japanese JENDL4.0 database only includes hydrogen in light water, deuterium in heavy water, parahydrogen, orthohydrogen, paradeuterium, orthotritium, polyethylene, graphite, beryllium oxide, benzene, The thermal neutron scattering database of 15 materials such as beryllium, liquid methane, solid methane, hydrogen in zirconium hydride, and zirconium in zirconium hydride, just because the above three basic evaluation databases lack the thermal neutron scattering database of fluorine salts, Therefore, in the previous physical calculations of reactors, the bound thermal neutron scattering of fluorine salts was ignored, and only the scattering process of thermal neutrons and fluorine salts was treated with a simplified free gas model.

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