基于Python的放射性核素大气扩散程序初步开发与验证

刘朋杰，张旖旎，刘天元

摘 要：核污染擴散问题是世界各国关注的问题，尤其是在日本福岛核事故发生之后，研究核素扩散问题有利于辐射防护。本文建立了无风与有风条件下的核素扩散模型并将其应用于软件的开发。据 定律和质量守恒定律得出核素在无风情况下随时空的扩散方程；借助概率论知识得出有风情况下的高斯扩散方程。考虑到地面反射的影响，排风设备的冲力和热排放的浮力等产生的烟羽抬升以及放射性物质的衰变，对模型进行了适当的改进。基于得出的结果用Python 编程绘图，得出的结论与实际分析一致，验证了模型的可靠性。

关键词：核素扩散模型 高斯烟羽模型Fick 定律Python

Preliminary Development and Validation of a Radionuclide Atmospheric Diffusion Process Based on Python

LIU Pengjie1，ZHANG Yini1，LIU Tianyuan1

（1.School of Nuclear Science and Engineering， North China Electric Power University， Beijing 102206， China）

Abstract： The issue of proliferation of nuclear pollution is a matter of concern to all countries in the world， especially after the nuclear accident in Fukushima， Japan. Studying the proliferation of nuclide is conducive to nuclear safety. This paper establishes a nuclide diffusion model under windless and windy conditions， and applies it to the development of software. First， according to the law of Fick and conservation of mass， the diffusion equation of nuclide at any time and in the absence of wind is obtained. Secondly， the Gaussian diffusion equation in windy conditions is derived from the knowledge of probability theory. Considering the influence of ground reflections， plume rise resulted from exhaust equipment impulse and thermal discharge buoyancy and decay of radioactive material， this article makes some appropriate modifications to the model. Finally， based on the results obtained， Python is used to program and draw， the conclusion got from the figure is consistent with the actual analysis， verifying the robustness of the model.

Keywords： Nuclide diffusion model， Gaussian plume model， the law of Fick， Python