Method for analyzing trace neptunium content in large amount of uranium in nuclear fuel post-treatment process

Abstract

The invention belongs to the technical field of analytical chemistry, and relates to a method for analyzing the content of trace neptunium in a large amount of uranium in a nuclear fuel aftertreatmentprocess. The analysis method sequentially comprises the following steps: (1) taking a sample with a certain volume, and adding concentrated nitric acid to adjust the concentration of nitric acid to 1-2 mol/L; (2) adding a ferrous aminosulfonate solution into the sample, uniform mixing, and standing for a period of time; (3) adding an extraction agent into the sample for extraction, performing centrifugal separation, removing a water phase, and retaining an organic phase; (4) washing the organic phase with a washing solution for 2-5 times, removing the water phase after each washing, and retaining the organic phase; (5) diluting the organic phase with isopropanol, and analyzing the diluted organic phase with ICP-MS provided with an organic sample injection system. By utilizing the method for analyzing the trace neptunium content in the large amount of uranium in the nuclear fuel post-treatment process, the analysis of the trace neptunium content in the large amount of uranium in the nuclear fuel post-treatment process can be simply, conveniently, quickly and accurately carried out with less required sample amount and little interference.

Description

technical field [0001] The invention belongs to the technical field of analytical chemistry, and relates to a method for analyzing trace neptunium content in a large amount of uranium in a nuclear fuel reprocessing process. Background technique [0002] Long-lived isotopes of the transuranic element neptunium 237 Np is an extremely toxic nuclide (T 1 / 2 =2.144×10 6 a), and the only isotope of neptunium in cooled spent fuel. Nuclear fuel reprocessing requires very strict control of neptunium in uranium products, and the analysis of trace neptunium content in large amounts of uranium has not been well resolved. [0003] In samples containing more uranium in the nuclear fuel reprocessing process, the ratio of uranium to neptunium can reach 1×10 7 , 238 U for trace 237 Np analysis has a lot of interference. To accurately measure the neptunium concentration of the sample solution, strict separation pretreatment is required to separate uranium and neptunium before analysis ca...

AI Technical Summary

Problems solved by technology

But the method also exists 238 U pair 237 The interference of Np; the sampling volume of the measured sample is large, such as the sampling volume of the uranium product sample needs to be 20ml; in the ion exchange process, the pretreatment and separation time of a sample is about 2-5 hours, and the operation process such as adsorption and washing takes a long time , making the tetravalent neptunium adsorbed on the ion exchange column unstable, and may be oxidized to pentavalent in advance and desorbed, resulting in the loss of part of the neptunium, which may increase the analysis error of some samples (see: Wang Xiaorong, Lin Cansheng, Liu Junling, etc. Uranium trace 237 Analysis of Np. Nuclear Chemistry and Radiation Chemistry, 2002,2(1):16-20.)

[0007] Therefore, the above methods have disadvantages such as uranium interference, large analysis error, long analysis time, complicated operation steps and large sampling volume when analyzing nuclear fuel reprocessing process samples.