Isotope dilution mass spectrometry method for determining content of uranium in uranium niobium alloy

Abstract

The invention discloses an isotope dilution mass spectrometry method for determining the content of uranium in a uranium niobium alloy. A formula for calculating the content of uranium in the uranium niobium alloy is derived according to an isotope dilution mass spectrometry principle. A decomposition process of the uranium niobium alloy is researched, the sampling quantity and the amount of a diluent are optimized, and the influences of mass spectrum line interference and alloy element interference on a measurement result are discussed. The method comprises the following steps: adding nitric acid and hydrofluoric acid to quantitatively dissolve the uranium niobium alloy, adding a quantitative amount of a uranium isotope diluent to directly prepare a mixed sample solution, determining the mixed solution and the uranium isotope proportion in the uranium niobium alloy sample through mass spectrometry, and calculating the content of uranium in the uranium niobium alloy. Quantitative separation of uranium is not needed by the determined method. An XRF technique, an ICP-AES technique and an element analysis technique are used to measure the content of niobium and the total content of impurity elements in the uranium niobium alloy, and back stepping is carried out to obtain the corresponding uranium content order in order to verify the accuracy of the analytical result, and the obtained result is consistent with a result obtained through the experiment method. When the method disclosed in the invention is used to analyze the uranium niobium alloy sample, the relative standard uncertainty of determination results is 0.2% (6 determinations), and the expanded uncertainty is 0.5% (95% confidence level).

Description

[0001] technical field [0002] The invention belongs to the technical field of casting, and in particular relates to an isotope dilution mass spectrometry method for measuring uranium content in uranium-niobium alloys. [0003] Background technique [0004] The chemical composition of U-Nb alloy has a great influence on the properties of the alloy, so the accurate determination of its chemical composition is an essential quality monitoring step in the U-Nb alloy process. The chemical composition of U-Nb alloy includes U, Nb and impurity element content. Among them, Nb content is generally determined by emission spectrometry or X-ray fluorescence spectrometry, metal impurity elements are determined by emission spectrometry, and non-metal impurity elements are determined by element analyzer. In recent years, with the increasingly strict quality control and the requirement of material balance of nuclear materials, the determination of U content in the matrix of U-Nb allo...

AI Technical Summary

Problems solved by technology

Common spectroscopic measurement techniques, because the spectral lines of uranium are easily interfered, are not suitable for the measurement of uranium content in uranium-niobium alloys. Other chemical analysis techniques, because they involve the quantitative separation of uranium and niobium and other impurities, the chemical treatment process is equivalent. cumbersome