核电厂事故应急局地实时剂量评价系统的模式与参数

本文介绍在核电厂事故应急局地实时剂量评价系统中应用的拉格朗日烟团模式及相应的参数。对烟团轨迹考虑了事故期间风向、风速的变化,采用有效扩散参数以考虑烟团迁移期间大气稳定度等气象条件的变化,干沉积采用源耗减模式,湿沉积采用冲洗系数方法,还考虑了放射性衰变及烟团部分穿透混合层的修正。鉴于我国在建核电厂皆位于沿海地区,文中还给出了内边界层条件下烟团公式的处理方法。对于实时剂量评价,主要考虑了烟云浸没外照射、吸入内照射和沉积放射性核素外照射三种照射途径。最后,以秦山核电厂为例估算了 PWR1事故的环境影响,给出了部分计算结果。     

秦山核电站计算机实时剂量评价系统的研究和应用

介绍了秦山核电站一期工程(300MW机组)专设应急设施之一——计算机实时剂量评价系统设置的目的和评价方法的选择。根据秦山核电站周围环境的特征,选用了模拟连续烟流的动态烟团模式及相应的三维风场模式。着重描述了秦山核电站计算机实时剂量评价系统(CRTDAS)的模式与参数、硬件和软件的构成与开发、评价步骤和主要功能,包括工厂安全参数、气象参数和环境辐射参数的获取与显示,工厂状况评价和源项估算,环境     

RODOS系统中两种大气弥散模型链的比较

通过对RODOS系统中两种大气弥散模型链在均匀和非均匀气象条件情况下风场与大气扩散的计算结果进行比较，表明：在进行核事故后果评价中采用风场模式确定烟羽输送轨迹是非常重要的，特别是对于复杂地形厂址；分段烟羽模式的ATSTEP模型在整个评价区采用单点风资料，仅在乎坦均匀地形和稳定条件下是一种有用的近似，对于复杂地形厂址其适用性将受到限制；从对风场的处理方法和对大气扩散的模拟角度看，采用Lagrange移轨迹烟团模式的RIMPUFF模型模拟的结果相对要好。     

秦山核电站计算机实时剂量评价系统的研究和应用

介绍了秦山核电站一期工程(300MW机组)专设应急设施之一——计算机实时剂量评价系统设置的目的和评价方法的选择。根据秦山核电站周围环境的特征,选用了模拟连续烟流的动态烟团模式及相应的三维风场模式。着重描述了秦山核电站计算机实时剂量评价系统(CRTDAS)的模式与参数、硬件和软件的构成与开发、评价步骤和主要功能,包括工厂安全参数、气象参数和环境辐射参数的获取与显示,工厂状况评价和源项估算,环境后果评价等。最后介绍了该评价系统的具体应用、模拟计算、近期实验和有待改进或发展的方面,并对这一领域今后的发展提出了一些合理性建议。     

田湾核电厂核事故场外后果评价系统简介

本文介绍江苏田湾核电厂核事故场外后果评价系统(TW-NAOCAS)的概况。该系统软件包括操作管理子系统,数据传输、气象数据预处理与风场诊断模块,风场预测模块,大气弥散模块和剂量估算与干预措施模块。TW-NAOCAS系统能在30 min内给出评价区(近区为20×20 km2、空间分辨率500 m,远区为80×80 km2、、空间分辨率4 km)的风场以及设计基准事故(DBA)和超设计基准事故(BDBA)释放的69种核素在各网格的浓度、预期剂量、隐蔽与撤离的可避免剂量及其区域等信息。文中简述了主要物理模块的计算模式,最后介绍了风场预测、大气扩散与剂量估算三个模块及例题的测试结果。     

Boussinesq近似对于爆炸烟云运动数值计算的影响

采用Boussinesq近似模型与不可压缩模型研究了不同密度比的烟团在标准分层大气条件下的烟云运动过程,分析了两种模型计算烟云之差异,得出烟团密度与周围大气密度比越小,两种模型计算结果相差越大的结论,当密度比达到0.9时,两种模型计算结果基本一致,为研究爆炸烟云的运动提供参考。     

田湾核电站场外事故后果评价系统--TW-NAOCAS

从田湾核电站早期应急的需要,开发了一套核事故场外后果实时评价计算机系统软件（TW-NAOCAS）。该系统设计为一个连接多种模型（数据预处理、风场预测、大气弥散、剂量估算和干预与防护对策评估）和数据库的综合系统。本文对该系统进行介绍,并通过模式比对,对系统物理模型有效性进行了初步分析。结果表明,该系统采用的物理模型和运行设计是有效而可靠的。     

拉格朗日烟团模型的大气扩散系数自适应修正

在核事故后果实时评价系统中,拉格朗日烟团模型作为大气扩散模型得到了广泛应用。大气扩散系数是影响烟团模型的重要参数之一,本文提出一种动态修正拉格朗日烟团模型的大气扩散系数的自适应方法,以提高放射性核素浓度分布计算的准确性。该方法利用观测的核素浓度数据、气象数据和源项释放数据,以最小二乘法实时地对大气扩散系数进行了估计。使用大气扩散模型验证工具MVK中的Kincaid实验数据,将动态大气扩散系数自适应修正方法与传统的以Pasquill-Gifford（P-G）曲线为基础的方法相比较,结果表明,大气扩散系数自适应修正方法能提高拉格朗日烟团模型计算结果的准确性。     

爆炸烟云运动的试验与数值模拟研究初探

通过高速CCD摄影机和高性能摄像机对一定量的TNT炸药爆炸产生的火球和烟云的运动过程进行了记录,按照实时记录结果,将爆炸分为火球发展阶段和烟云上升阶段来研究;利用高速CCD拍摄结果对爆炸火球进行分析,在分析爆炸烟云运动机理的基础上,将试验火球最大尺寸作为初始条件建立了数值求解模型,采用2维变密度投影法对试验烟团的发展过...     

广东省核电站核事故场外后果预测评价系统

广东省核电站核事故场外后果预测评价系统（GNARD2．0）是一个核电站事故场外辅助决策计算机软件系统,该系统具有在线和实时评价和预测事故后果的能力,能够计算风场,放射性物质浓度和剂量,进而给出超过干预水平的区域及区域内的人口,应急设施等信息,并能对应急防护行动实施进程进行模拟和计算,得出可防止剂量以评价行动的有效程度,本文简要介绍了该系统的软硬件组成和后果评价模式,总结了系统开发经验,并对系统的未来发展方向进行了讨论。     

Stopping powers of Be,Al, Ti,V, Fe,Co, Ni,Cu, Zn,Mo, Rh,Ag, Sn,Ta, Pt and Au For 6.5 MeV protons

The stopping powers of Be, Al, Ti, V, Fe, Co, Ni, Cu, Zn, Mo, Rh, Ag, Sn, Ta, Pt and Au for 6.5 MeV have been measured using a surface barrier silicon detector. The accuracy of the results is ± 0.3%. The detail of the experimental procedures is described. The results have been compared with the Risø data and the Aarhus data of Andersen et al. The present results for Al, Cu and Ag agree very well with the Aarhus results at 6.5 MeV. The mean excitation energy has been extracted from the present results using the Bonderup shell correction, the Barkas correction and the Bloch correction. The parameters x and b which appear in the Bonderup shell correction and the Barkas correction have been newly determined as x = 1.358 and b = 1.3. The present mean excitation energy agrees very well with the I values obtained by other authors. It has been confirmed that the Bonderup shell correction is quantitatively correct for 6.5 MeV protons.     

Wavelengths,transition probabilities,and oscillator strengths for M-shell transitions in Co-, Ni-, Cu-, Zn-, Ga-, Ge-, and Se-like Au ions

Wavelengths, transition probabilities, and oscillator strengths have been calculated for M-shell electric dipole transitions in Co-, Ni-, Cu-, Zn-, Ga-, Ge-, and Se-like Au ions. The fully relativistic multiconfiguration Dirac–Fock method, taking quantum electrodynamical effects and the Breit correction into account, was used in the calculations. Calculated energy levels of M-shell excited states for Cu-, Zn-, Ga-, Ge-, and Se-like Au ions from the method were compared with available theoretical and experimental results, and good agreement with them was achieved.     

Gamma-Ray Production Cross Sections for Interactions of 14.8 MeV Neutrons with O,Na, Al,Cl, Cr,Fe, Ni,Cu and Pb

Production cross sections for 85 discrete γ-rays at 125° were measured with a Ge(Li) detector for interactions of 14.8 MeV neutrons with natural samples of O, Na, Al, Cl, Cr, Fe, Ni, Cu and Pb. The obtained cross sections were compared with the results of previous works. For O, Na, Al, Cr and Ni, the present results agree with the previous data measured with monoenergetic neutron sources; for Cl, Fe, Cu and Pb, the present results are larger than the previous data. In comparison between the present results shown by histograms of γ-ray energy and unfolded data, a considerable discrepancy is found from some of the previous data for Fe.     

Measurements of the total effective cross sections for resonance neutrons in Pd,Os, Ir,Mo, In,I, Ta,Th, U238

The results of calculations of the level constants in the elements Pd, Os, Ir, Mo, I, In, Ta, Th, U²³⁸ are presented; the cross sections for these elements have been published earlier. New measurements for the cross sections in Ir, Th, U²³⁸ are cited. The measurements were made with a mechanical-chopper spectrometer with a resolution of 0.08 sec/m in the energy region from 4.5 to 10,000 ev. The integrated and differential curves for the distribution of neutron widths in these elements are plotted.Presented at the International Conference on Nuclear Reactions in Amsterdam (June 1956).The authors take this opportunity to express their gratitude to U. Chi-Kwa and Suan Chi-Ling for their assistance in the mathematical analysis of the experimental results, G. M. Kukavadze for the mass-spectro-graphic analyses of the samples, V. N. Bovinoi and M. P. Anikinoi for providing the chemical analyses and A. I. Ermakov, N. S. Rezvyakov, G. V. Rukolaine and K. A. Trostinoi for help in building the analyzer and in carrying out the measurements.