Method for calculating relative content of Pu-242 nuclide

Abstract

The invention belongs to the technical field of nuclear radiation and detection, and relates to a method for calculating the relative content of Pu-242 nuclide. The method comprises the following steps: measuring characteristic gamma rays of 238Pu, 239Pu, 240Pu and 241Pu by utilizing a gamma spectrometer, and obtaining a relative detection efficiency curve of gamma rays with different energies byutilizing the characteristic gamma rays of 239Pu; and calculating the content of 238Pu, 239Pu, 240Pu and 241Pu relative to 239Pu according to the counting of the characteristic gamma rays of 238Pu, 239Pu, 240Pu and 241Pu in combination with the change of gamma ray detection efficiency along with energy, and then calculating the content of 242Pu relative to 239Pu. According to the method, the problem that 242Pu cannot be directly identified and the content of 242Pu cannot be detected is solved by utilizing the existing detection instrument, and the conditions of various irradiation histories, various burnup depths and various spent fuel cooling time of various components and various reactor types are considered in the algorithm, so that the method is effective and accurate. The relative error of the calculated 242Pu content is basically about 1%, and the method has very high precision.

Description

technical field [0001] The invention belongs to the technical field of nuclear radiation and detection, and relates to a spent fuel reprocessing process that has nothing to do with the irradiation history of fuel assemblies. 242 Calculation method of relative content of Pu nuclides. Background technique [0002] Plutonium isotopes in spent fuel assemblies mainly include 238 Pu, 239 Pu, 240 Pu, 241 Pu and 242 Pu. Usually, the identification of plutonium nuclides is mainly realized by measuring the characteristic gamma rays in the middle and low energy regions. The characteristic gamma ray method requires nuclides to have gamma rays of specific energy that can be clearly distinguished from other nuclides. nuclide 238 Pu, 239 Pu, 240 Pu, 241 Pu has characteristic gamma rays that can be used for nuclide identification. In order to alleviate the demand for quantitative calibration of detectors and reduce the excessive requirements for energy resolution and electronic s...

AI Technical Summary

Problems solved by technology

[0005] At present, it is calculated by Pu element and other nuclides 242 The calculation method of Pu nuclide content, such as the formula used by the MGA program developed by the University of California Lawrence Radiation Laboratory (UCRL): [242]=a+b[239]+c[240]+d[241]+e [239] 2 +f[240] 2 +g[241] 2 , where a~g represent coefficients, and those in square brackets represent the content of each nuclide of Pu element; and the formula used in China: However, existing calculation methods do not take into account 238 The influence of the Pu nuclide content, and the error between the calculation result and the actual value is relatively large, the relative error is generally about 50%, and it can only guarantee the obtained 242 The Pu nuclide content and the actual value are within an order of magnitude, and the practicability is low

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