桶装α废物分类检测装置的中子吸收校正技术研究

Study on neutron absorption correction technology of the waste drum assay system

桶装α废物分类检测装置(Waste Drum Assay System,WDAS)在测量废物桶中铀、钚含量时受到桶中介质吸收的影响,从而影响测量精度,为核材料衡算和军控核查带来挑战。本文提出了一种用于校正中子符合计数的方法,通过建立废物桶介质对外加中子源的吸收校正因子和对样品的吸收校正因子的刻度函数关系校正废物桶含钚废物的符合中子计数,从而准确地测量α废物活度和质量。经实验验证,校正后~(252)Cf活度与标准值之间的相对偏差显著减小,校正结果均优于7%。实验验证了方法的可行性,为该装置后续的推广应用提供了基础。

[Background]Measurement of uranium and plutonium content in the waste drum assay system(WDAS)is affected by the absorption of the matrix in the drum due to the neutron coincidence counting of waste.[Purpose]This study aims to propose a method for correcting neutron coincidence counting applicable to the classification detection of WDAS.[Methods]First of all,the calibration function between the absorption correction factor of the external neutron source and the sample in the waste drum was established.Then the coincidence neutron count of plutonium in the waste drum was corrected according the calibration function.Thereby the activity and quality ofαwaste were accurately measured.Finally,a 252Cf source was taken as external neutron source for experimental verification of neutron absorption correction of WDAS.[Results]Experimental results show the relative deviation between the corrected 252Cf activity and the standard value is significantly reduced,and the deviation of the experimental correction results is better than 7%.[Conclusions]The absorption correction method improves the accuracy of the results and provides the basis for the extension and application of the device.