基于Python的放射性核素大氣擴散程序初步開發與驗證

劉朋杰，張旖旎，劉天元

摘 要：核污染擴散問題是世界各國關注的問題，尤其是在日本福島核事故發生之后，研究核素擴散問題有利于輻射防護。本文建立了無風與有風條件下的核素擴散模型并將其應用于軟件的開發。據 定律和質量守恒定律得出核素在無風情況下隨時空的擴散方程；借助概率論知識得出有風情況下的高斯擴散方程。考慮到地面反射的影響，排風設備的沖力和熱排放的浮力等產生的煙羽抬升以及放射性物質的衰變，對模型進行了適當的改進。基于得出的結果用Python 編程繪圖，得出的結論與實際分析一致，驗證了模型的可靠性。

關鍵詞：核素擴散模型 高斯煙羽模型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