应用分段烟羽模式估算秦山核电厂(二期)设计基准事故概率后果

采用天气取样技术和分段烟羽模式估算了秦山核电厂二期工程一旦发生设计基准事故，在半径８０ｋｍ评价区内可能造成的事故概率后果。天气取样采用分层取样技术，根据秦山二期厂址百米气象铁塔一年逐时气象观测数据取。持续时间长达３０天的事故释放采用分段烟羽模式由５个不同持续时间，不同释放量的烟段模拟；应用有效扩散参数概念以描述大气稳定度变化对扩散参数的影响，扩散参数采用厂址实测值。     

海岸热边界层熏烟模式的应用研究

在海风和陆地热边界层条件下，水陆边界处高架点源可能发生熏烟污染，通常可以应用熏烟扩散模式进行模拟。但是，常用熏烟模式中假设烟流进入边界层内后立即在垂直方向均匀分布，导致算出不合理的高浓度区。假设烟流进入边界层后．主要受到因为大气稳定度变化扩散条件因此变化的影响，改进了计算公式。把原有模式和改进模式分别应用于某滨海区的一个电厂高架点源，结果表明，改进后模式的计算结果更加合理。因此建议类似工作采用改进后的模式。     

辽东湾地区大气扩散因子的应用研究

本文采用高斯烟习模式计算了辽东湾地区的大气扩散因子，为厂址选择提供了一种实用方法。     

年均大气扩散因素在待建厂址选择的应用

采用年均大气扩散因子预测建设项目大气污染和气载污染物在各种环境条件下浓度在空间及时间上的分布,可以客观的评价项目厂址选择的合理性.本文具体分析了年均大气扩散因子的影响因素、计算方法及应用条件,将其结果有效地应用于建设项目待建厂址的选择之中.     

放射性物质污染及其防治

X591 X32 9803255应用分段烟羽模式估算秦山核电厂(二期)设计基准事故概率后果/胡二邦一(中国辐射防护研究院)//环境科学学报/中科院环委会一1998,18(2)一181一187环信X一9 采用天气取样技术和分段烟羽模式估算了秦山核电厂二期工程(2 x 600MW)一旦发生设计基准事故,在半径80km评价区内可能造成的事故概率后果。天气取样采用分层取样技术,根据秦山二期厂址百米气象铁塔一年逐时气象观测数据获取。持续时间长达30天的事故释放采用分段烟羽模式由5个不同持续时间、不同释放量的烟段模拟;应用有效扩散参数概念以描述大气稳定度变化对扩散参数…     

不同气象场对核电厂核素大气扩散的影响

核电厂事故时放射性核素大气扩散特征是核电厂环境影响评价中重点关注问题。目前核电厂环境影响评价中采用单一气象场驱动进行预测分析不足以真实反映放射性核素事故时大气扩散特征。以某核电厂厂址为研究对象,利用核事故短期大气弥散因子计算软件PAVAN(Potential Accident Consequence Assessments at Nuclear Power Plants)模拟不同气象场驱动情景下核电厂事故时放射性核素大气扩散特征,以确定气象场驱动差异对事故时放射性核素大气扩散的影响。结果表明:多年气象场驱动条件下非居住区边界和规划限制区边界的短期大气弥散因子年均值最大值分别为单一气象场驱动条件的1.05和1.04倍,均出现在S方位。不同情景下非居住区边界大气弥散因子年均值最大值在CASE2和CASE4情景下相同,但出现方位不同,分别出现在S和NE方位;CASE4情景下大气弥散因子年均值变异程度大于CASE2情景;非居住区边界30 d内CASE2、CASE3和CASE4情景下短期大气弥散因子的最大值分布范围依次为(6.01E-5~7.78E-5)、(5.72E-5~7.79E-5)和(6.29E-5~7.79E-5)s/m3。不同情景下规划限制区边界大气弥散因子最大值从大到小依次为CASE2CASE4CASE1CASE3,依次出现在S、NE、S、NE方位;规划限制区边界30 d内CASE2、CASE3和CASE4情景下短期大气弥散因子的最大值分布范围依次为(1.17E-5~1.95E-5)、(1.09E-5~1.98E-5)和(1.24E-5~1.98E-5)s/m3。     

天津市突发事故条件下大气污染的应急模拟

基于数值天气预报模式和自动气象站观测资料,采用随机游走粒子-烟团模式对天津市突发事故条件进行应急示踪模拟试验.结果表明,模式能在10min内给出计算结果,并能较好地模拟大气突发事故的大气扩散过程,粒子的散布和积分浓度的分布均能反映出大气突发事故污染物扩散路径和影响范围的变化,可以作为事故应急决策系统的大气扩散模块,为早期应急和后果评价提供更接近实际的信息.     

核电厂野外示踪试验的三维数值模拟研究

为深入分析国内某拟选滨海核电厂址的大气扩散特征,在现场野外示踪试验的基础上,采用计算流体动力学（CFD）软件Fluidyn-PANACHE,结合三维GIS、结构化贴体网格构建、区域加密等技术方法,创建了可模拟野外示踪试验的精细化大气扩散模拟系统.相比于高斯模式,CFD模式能够更好地模拟示踪剂在不同下风距离处的峰值浓度和烟羽宽度,对近场及复杂下垫面条件下的扩散模拟更贴合实际,且可在稳态模拟的基础上获得连续变化风场中接近实时模拟的仿真效果.模拟结果的偏差统计分析表明,CFD稳态模拟和高斯模拟的统计学评价指标均位于国际公认的可接受范围内,CFD模拟的随机偏差优于高斯模拟.因此,CFD模式可用于辅助和优化其他核电厂址的野外示踪试验工作,提高我国核安全审评的效率和针对性.     

固体微粒的扩散与行星边界层风速廓线

文章利用大气边界层风速廓线的理论和实验研究结果,重新推导了高斯扩散沉积模式中烟轴高度、地面反射系数及输送因子表达式,从而导出了能描述风速随高度变化的新的高斯扩散沉积模式。 文章还利用数值计算的结果讨论了风速廓线对地面相对浓度的影响。     

草甘膦农药泄漏事故风险评价研究

以草甘膦生产为例,在高斯扩散模型的基础上,考虑污染物在大气中的衰减,推导出评估大气突发性事故危害区的定量估算公式。该公式使用条件与高斯扩散模型相同,通过与高斯模式的验证分析,结果精确,可用于直接求取任意浓度等值线的精确位置。结合事故发生的概率、气象条件(包括风速、风向、稳定度)、周围的人口密度、有毒有害物质的半致死浓度计算了风险值。草甘膦生产中,储罐泄漏甲醇风险值9.9×10-4人/a。     

Model calculating annual mean atmospheric dispersion factor for coastal site of nuclear power plant

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福岛核事故对中国核电站厂址选择影响研究

日本福岛核事故源于两个直接因素--地震和海啸,以及两因素的叠加,并导致放射性泄漏对周围居民产生重大影响。针对这些问题,分析中国大陆核电站厂址的地震发生概率、海啸发生概率和人口分布因素,由此评价我国核电站厂址选择的安全性。结果证明:我国大陆核电站远离地震带;沿海不会发生特大海啸;核电站周围人口分布密度符合安全标准,我国核电站具有较高的固有安全性。同时,此次福岛事故也是对我国核电发展的警示,要求不可忽视小概率的超基准设计事故以及多个超基准设计事故叠加的情况;要重新审查中国抗震和海啸等极限事故的标准;要考虑人口密度;要避免两个核电站建设过密的情况。目前,我国已经采取安全检查等措施确保核电站的安全性。这次福岛事故对我国乃至世界核电的发展都是宝贵的经验教训。     

SRDAAR-QNPP:a computer code system for the real-timedose assessment of an accident releasefor Qinshan Nuclear Power Plant

ＳＲＤＡＡＲ－ＱＮＰＰ：ａｃｏｍｐｕｔｅｒｃｏｄｅｓｙｓｔｅｍｆｏｒｔｈｅｒｅａｌ－ｔｉｍｅｄｏｓｅａｓｓｅｓｓｍｅｎｔｏｆａｎａｃｃｉｄｅｎｔｒｅｌｅａｓｅｆｏｒＱｉｎｓｈａｎＮｕｃｌｅａｒＰｏｗｅｒＰｌａｎｔＨｕＥｒｂａｎｇ;ＷａｎｇＨａｎ（Ｃｈ...     

Thermal internal boundary layer and its effects on air pollutants during summer in a coastal city in North China

The thermal internal boundary layer(TIBL) is associated with coastal pollution dispersion,which can result in high concentrations of air pollutants near the surface of the Earth. In this study, boundary layer height data which were obtained using a ceilometer were used to assess the effect of the TIBL on atmospheric pollutants in Qinhuangdao, a coastal city in North China.A TIBL formed on 33% of summer days. When a TIBL formed, the sunshine duration was 2.4 hr longer, the wind speed was higher, the wind direction reflected a typical sea breeze, and the boundary layer height was lower from 9:00 LT to 20:00 LT compared to days without a TIBL. If no TIBL formed, the average concentrations of PM_(2.5) and PM_(10) decreased with increasing boundary layer height. However, when a TIBL was observed, the average concentrations of PM_(2.5) and PM_(10) increased with increasing boundary layer height. Because the air from the sea is clean, PM_(2.5) and PM_(10) concentrations reached minimums in the daytime at 16:00 LT. After16:00 LT, the PM_(2.5) and PM_(10) concentrations increased rapidly on days when a TIBL formed,which indicated that the TIBL leads to the rapid accumulation of atmospheric pollutants in the evening. Therefore, the maximum concentrations of particulate matters were larger when a TIBL formed compared to when no TIBL was present during the night. These results indicate that it is suitable for outdoor activities in the daytime on days with a TIBL in coastal cities.     

某简易垃圾填埋场渗滤液在场底天然土层迁移模拟与长期预测

为了解我国早期建设的简易填埋堆场底部天然土层中污染物迁移状况,作者以安徽某填埋场为例,在前期现场勘查、取样和室内测试工作基础上建立了三维有限元分析模型,对宏量有机污染物COD在土层中的迁移状况进行了模拟分析.通过拟合求参获得COD在该场底土层中扩散系数、机械弥散系数和阻滞因子等运移参数的合理取值,在此基础上开展了污染物...     

Diurnal wind-structure variations and dispersion of pollutants in the boundary layer

A coupled boundary-layer model and Lagrangian particle model are used to investigate the role of boundary-layer shear especially that produced by inertial oscillations in affecting the horizontal dispersion of pollutants on time-scales of 24–36 h. The coupled models show that the amplitude and the effective periods of the inertial oscillations are the main cause of nocturnal accelerating dispersion. The effective width of the plume in the morning is determined by whether the morning daytime mixing coincides with the phase of the inertial oscillation being at a maximum or minimum value. The phase of the oscillation is determined by latitude. Thus, latitude is shown to be an extremely important parameter in determining horizontal dispersion. An analytical model is introduced to investigate the role of external parameters such as latitude in influencing the horizontal dispersion. The analytical model is based on a simple Ekman-type model for the daytime and nighttime boundary layer. The Ekman model is used to provide initial conditions to an inertial oscillation regime between the nighttime boundary layer and the old daytime boundary layer. The analytical model was able to reproduce the magnitude and phase of the inertial oscillations reasonably well. However, the Ekman model overestimates the shear in the boundary layer causing the inertial oscillation to be too large. A semi-empirical method was used to provide more reasonable estimates of the daytime boundary-layer structure. This semi-empirical approach gave rates of the horizontal dispersion which were in general agreement with the numerical results.     

A Lagrangian particle model of fumigation by breakdown of the nocturnal inversion

Several fumigation modelling studies are reviewed and an approach involving a coupled mesoscale grid point model and a Lagrangian particle dispersion model is chosen for further study. A number of particle model formulations are evaluated for their ability to maintain a well-mixed profile under steady-state convective conditions. The importance of using a formulation of the Langevin equation which is compatible with the specified turbulence parameterization is emphasised. Other considerations such as the form of the parameterizations and the magnitude of the timestep must also be taken into account.For prediction of hourly-averaged surface concentrations under fumigation conditions, it is found that a simple homogeneous turbulence formulation is equally effective as more sophisticated parameterizations involving inhomogeneity and skewness. Such a particle model, in conjunction with a mesoscale model for predicting the growth of the mixed layer, is able to reproduce well the results of the Deardorff and Willis (1982, Atmospheric Environment16, 1159–1170) laboratory experiments on fumigation.     

广东省土地覆盖变化对植被净初级生产力的影响分析

理解土地利用/覆盖变化对植被净初级生产力（Net Primary Productivity,NPP）的影响对于全球碳循环和粮食安全具有重要意义。论文采用优化的CASA（Carnegie-Ames-Stanford Approach）模型估算广东省2000、2005和2010年NPP,分析NPP的空间格局和土地覆盖的时空动态,研究土地覆盖变化对NPP的影响。结果表明：1）广东省NPP空间分布不均,形成一系列高值区和低值区;总体上是粤中区最高,珠三角区最低。2）2000—2010年广东省土地覆盖变化程度增强,城市用地和耕地变化最大,主要集中在珠三角区和粤中区。3）在气候变化条件下,以城市扩张为主导的广东省土地覆盖类型变化整体上造成NPP的损失,损失量主要来自林地和耕地向低生产力土地覆盖类型的转换,尤其是被城市用地占用;不同生态区NPP损失差异显著,珠三角区和粤中区NPP损失较为严重;2005—2010年珠三角区NPP损失量有所降低,其他生态区均有所增加,体现了城市扩张对NPP影响的复杂性。     

水环境容量一维计算中不均匀系数研究

文章介绍传统地表水环境容量一维计算方法,针对其缺陷提出考虑不均匀系数的计算方法。介绍混合区概念及其允许范围,应用二维水质模型求解不均匀系数,并分析其计算结果。作为实例,对广西红水河某河段水环境容量进行计算,取得了很好的效果。