Solid state and liquid state villiaumite thermal neutron scattering database obtaining method and database

Abstract

The invention relates to a solid state and liquid state villiaumite thermal neutron scattering database obtaining method and a database; the method comprises the following steps: 1, using a crystal lattice dynamics program based on the primary quantum mechanics principle to calculate phonon spectrum distribution of solid state villiaumite crystal and liquid state villiaumite solution; in addition, using a statistics physical method based on the molecule dynamics to calculate the diffusion coefficient of each villiaumite ion of the liquid state villiaumite solution; 2, supplying the phonon spectrum distribution and diffusion coefficients obtained in the step1 to a data processing program NJOY, thus obtaining solid state and liquid state villiaumite thermal neutron scattering data; 3, matching corresponding nucleus database index files according to different application purposes, and the index files and the thermal neutron scattering data obtained in step2 can form a complete thermal neutron scattering database. The invention also discloses the database obtained by the method, thus filling the blanks in the thermal neutron scattering database making field in international solid state villiaumite crystal and liquid villiaumite solution multi-group transport and subgroup resonance calculation.

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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