Preparation method of uranium and impurity element standard substances in triuranium octaoxide

Abstract

The invention relates to a preparation method of uranium and impurity element standard substances in triuranium octaoxide. The preparation method comprises the following steps: step one, sufficientlydissolving the raw material of triuranium octaoxide with MOS-level nitric acid; step two, preparing a constant-value element solution; step three, filtering a uranyl nitrate solution obtained in the step one; step four, converting the uranyl nitrate solution added with constant-value elements into a precipitation reaction tank; step five, filtering an ammonium diuranate sediment obtained in the step four; step six, carrying out drying, pyrolysis and calcinations on the ammonium diuranate sediment added with the constant-value elements in sequence to obtain the triuranium octaoxide product; andstep seven, carrying out grinding, electrostatic elimination, sieving and blending on the triuranium octaoxide product prepared and obtained in the step six by using a ball grinding mill. The preparation method solves the technical problems of quantitative addition and uniform distribution of trace constant-value elements in the triuranium octaoxide product, and is high in technological controllability.

Description

technical field [0001] The invention belongs to the field of standard substance preparation, and in particular relates to a method for preparing standard substances of uranium and impurity elements in triuranium octaoxide. Background technique [0002] Nuclear fuel elements are the "core" of nuclear power plant reactors, and uranium dioxide for the production of nuclear fuel elements is an important part of nuclear fuel elements. The content of impurity elements in uranium dioxide is directly related to the quality of nuclear fuel elements, and it is necessary to strictly control the impurity elements in uranium dioxide. content. UO3 is one of the most important uranium oxides, and it is also the most stable uranium oxide, because uranium dioxide, uranium hexafluoride and uranium tetrafluoride are not stable in the air, so U3O8 standard material is generally used. , used for the traceability of the production process of nuclear grade uranium dioxide (powder and pellets), ur...

AI Technical Summary

Problems solved by technology

[0003] At present, the types of fixed value elements of the existing U3O8 standard substance are relatively small, and some impurity elements only give reference values. The U3O8 standard substance GBW04242 and GBW04242 with the most types of fixed value elements have only 20 kinds (without U, Ti, V, W, Nb, Sb, Pb and other natural uranium dioxide technical indicators require limit value elements), some impurity elements (such as K, Na, Th, Ti, Mo, Al, Zn, Ca, Mg) fixed value level and At this stage, the actual impurity content of uranium dioxide products produced in my country varies greatly, and none of them has any +4 The fixed value with the total carbon TC cannot play a good role in value transfer and quality control in the production process of uranium dioxide

[0004] The preparation of U3O8 reference material mainly adopts synthetic matrix method and natural matrix method. The synthetic matrix method is to use purified high-concentration uranium-containing solution as raw material, add the required definite value element solution to the uranium-containing solution, and precipitate to form heavy Uranium salts are dried, decomposed, calcined, sieved, mixed and packaged to obtain U3O8 standard substances. The advantages of this method are that the raw materials are easy to obtain, the types and value ranges of fixed-value elements are controllable, and the addition effect is good. , good uniformity, but the disadvantage is that the process is complicated, the preparation time is long, and it is easy to cause pollution of fixed-value elements

The natural matrix method uses high-purity U3O8 products as raw materials, directly adds fixed-value element solids or fixed-value element solutions to the raw materials, and then calcines, sieves, mixes and subpackages to obtain U3O8 standard substances. The advantage of this method is that the process is simple, the preparation time is short, and it is not easy to introduce pollution. The disadvantage is that the type and value range of the fixed value elements are greatly affected by the collective composition of raw materials, and the uniformity is poor.

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