小型动力堆海上核事故后放射性核素在大气和海洋中扩散研究

为准确评估小型动力堆海上严重核事故后释放的气载核素造成的海洋放射性污染水平,以小型动力堆断电诱发的严重核事故为例,建立核素在大气和海洋中扩散的计算模型,计算事故后大气和海洋中¹³⁷Cs的放射性污染水平,并分析了气载核素释放高度、大气稳定度对沉降核素海洋扩散的影响。结果表明,在一定的释放高度下,源下风轴线上表层海水中核素的时间积分浓度随下风向距离的增大呈先升高后下降的变化规律;在离源一定距离内,释放位置越高,表层海水中核素的时间积分浓度越小;在离源一定距离外,大气越不稳定,表层海水中核素的时间积分浓度越小。

Research on Dispersion of Radionuclides in Atmosphere and Ocean after Nuclear Accident of Small Power Reactors at Sea

In order to accurately evaluate the level of marine radioactive pollution caused by airborne nuclides released after a serious nuclear accident at sea in a small power reactor, a severe nuclear accident of the small power reactor induced by the power failure is taken as an example. A calculation model of nuclide diffusion in the atmosphere and the ocean was established to calculate the level of 137 Cs radioactive pollution in the atmosphere and the ocean after the accident. The effects of airborne nuclide release height, atmospheric stability and source release ways on the marine dispersion of the nuclides were preliminarily discussed. The results indicated that at a certain release height, the time integrated concentration of nuclides in the surface seawater on the downwind axis increases with the distance, and then decreases after its maximum. Within a certain distance to the source, the higher the release location is, the smaller the time integrated concentration of the nuclides in the surface seawater is. When the distance from the source is greater than a certain distance, the more unstable the atmosphere is, the smaller the time integrated concentration of nuclides in the surface seawater is.