核应急辐射环境监测的准备和响应

日本核泄漏事故引发的核危机为人类安全和平地利用核能又一次敲响了警钟.核事故应急工作作为减小核电站危害环境和公众安全的最后屏障,将起到重要的作用,必须做好相关的准备和响应工作.核应急辐射环境监测工作是核应急工作的重要组成部分,在对核应急辐射环境监测进行准备和响应时主要遵循实用性、适用性和适度性并兼顾常规和应急监测的“平战...     

辐射环境安全事故的应急准备和演练

核技术的广泛应用给人类带来巨大利益的同时,也不可避免地产生一定程度的危害。结合辐射环境安全事故的特点,从事故类型、应急组织、应急响应准备、应急响应处置、应急演练的开展等方面详细阐述了如何开展辐射环境安全事故应急准备和演练,以提高辐射应急处置能力和水平。     

核电厂应急监测策略

综述了目前国内外核电厂环境辐射监测策略研究的现状与发展趋势,分析了核电厂应急监测需要关注的主要问题,包括应急监测的概念和范围、基本原则和要求、监测内容、组织管理策略、核事故时序和各阶段的应急监测策略、基础设施和设备需求、采样策略、需要关注的核素及其分析方法、质量管理策略等,在此基础上形成了应急监测策略的分析方法.提出今...     

核电厂放射性流出物监测工作探讨

简述了放射性流出物监测的重要性,分析了我国核电厂放射性流出物监测中存在问题,探讨了借鉴国际原子能机构安全及相关标准开展我国核电厂放射性流出物监测的管理机制、监测方案、监测报告和质量保证等具体要求与方法,并提出提升技术基础能力、完善法规标准、加强监管力度的建议.     

法国核电规划对江苏发展核电的几点启示

通过调研法国的核电规划、核电厂址的布局和核安全监督管理等工作,比较了法国和江苏在电力需求、区域特点、核电厂址分布等特点,在总结法国核电的发展历程对于江苏核电的规划发展值得借鉴的经验基础上,提出了江苏在建设滨海核电站的基础上新建滨河等内陆核电站需要注意的问题和对策.     

美国核电厂辐射环境监测与信息公开及其借鉴

综述了美国核电厂辐射环境监测管理体系和环境信息公开制度及法制化管理模式,对比分析了我国辐射环境监测与信息发布实际开展情况及存在问题,提出需借鉴美国核管理委员会(NRC,以下简称NRC)的管理经验,进一步完善我国辐射环境监测标准体系,建立辐射环境监测数据公开制度,加强公众参与制度建设,明确核电厂辐射环境监测管理边界等建议。     

基于ＷＲＦ与田湾核电站外围监控系统的区域风场模 拟对比分析

WR F模式是新一代中尺度预报模式和同化系统,通过 WR F 模式构建田湾核电站区域气象预报系统,可为江苏省建设先进的核应急决策支持系统提供坚实的理论基础和技术支持。介绍了田湾核电站区域 WR F 模式风场预报系统的构建和对比试验情况,通过数值模拟风场与实测结果的对比检验,WR F模式精细化的三维风场预测具有非常高的准确性。     

Radioactive Contamination Control by Atmospheric Dispersion Assessment of Airborne Indicator Contaminants: Numerical Model Validation

In this work, a numerical model is proposed to estimate air concentration of released airborne radioactive contaminants ¹³¹I and ¹³⁷Cs. A Gaussian dispersion model is used to assess the atmospheric dispersion of radioactive contaminants released continuously from a nuclear power plant as a result of an accident. The model uses various input parameters such as source height, release rate, stability class, wind speed, and wind direction. The validation of the model was carried out by comparing its predicted values with published experimental data. The model was extensively tested by simulating several accidental situations. The main conclusion drawn from these tests is that for large downwind distances from the release point, the contaminant concentrations predicted by the model diverge drastically from measured data, while for short distances, the predicted values generally agree quite well with experimental data. The obtained activity concentrations range from 1.57?×?10² to 6.43?×?10³ Bq/m³ for ¹³¹I and from 3.18?×?10^?2 to 9.72?×?10² Bq/m³ for ¹³⁷Cs. The estimated standard deviation coefficients values range of 7.2 to 6847.7 m, and the maximum absolute error predicted by the model for these parameters was less than 5%.     

Study of atmospheric stagnation, recirculation and ventilation potential at Narora Atomic Power Station NPP site

The atmosphere is an important pathway to be considered in assessment of the environmental impact of radioactivity releases from nuclear facilities. The estimation of concentration of released effluents in air and possible ground contamination needs an understanding of relevant atmospheric dispersion. This paper describes the meteorological characteristics of Narora Atomic Power Station (NAPS) Nuclear Power Project site by using the integral parameters developed by Allwine and Whiteman (Atmospheric Environment 28(4):713–721, 1994). Meteorological data measured during the period 2006–2010 were analysed. The integral quantities related to the occurrence of stagnation, recirculation and ventilation characteristics were studied for the NAPS site to assess the dilution potential of the atmosphere. Wind run and recirculation factors were calculated for a 24-h transport time using 5 years of hourly surface measurements of wind speed and direction. The occurrence of stagnation, recirculation and ventilation characteristics during 2006–2010 at the NAPS site is observed to be 33.8, 19.5 and 34.7 % of the time, respectively. The presence of strong winds with predominant wind direction NW and WNW during winter and summer seasons leads to higher ventilation (48.1 and 44.3 %) and recirculation (32.6 % of the summer season). The presence of more dispersed light winds during pre-winter season with predominant wind directions W and WNW results in more stagnation (59.7 % of the pre-winter season). Thus, this study will serve as an essential meteorological tool to understand the transport mechanism of atmospheric radioactive effluent release from any nuclear industry during the pre-operational as well as operational phase.     

Three-dimensional Modelling of Radionuclides Dispersion in a Marine Environment with Application to the Fukushima Dai-ichi Case

In this work, we present the implementation, verification and validation of a three-dimensional model able to reproduce the propagation of \(^{137}C_{s}\) radionuclide in coastal waters and its interaction with suspended sediments, in the framework of the open-source TELEMAC-MASCARET modelling system. The validation of the model was realized by comparing numerical results with field measurements of radionuclides concentration in the Japan Sea nearby the Fukushima Dai-ichi nuclear power plant (NPP). The developed model uses as external forcing the data available immediately after or during the accident, as, e.g. weather conditions (wind, pressure, temperature) and/or the harmonic components of tides. In contrast with previous models implemented in the study area, the model presented here is limited to the coastal area near Fukushima and refined in the coastal area close to the NPP. Numerical results show that the model is able to reproduce the propagation and diffusion of the released \(^{137}C_{s}\) in the vicinity of the Fukushima Dai-ichi NPP. Consequently, we show that the numerical results obtained with a small-scale model with a simple forcing are consistent, at a coastal scale, with models which employed a general circulation model based on data assimilation techniques or variation method for hydrodynamics. Therefore, this model could be employed in an emergency situation, when the dissolved radioactivity is considered.

     

2016—2021年四川省城市放射性废物库库区辐射环境监测

为提高四川省城市放射性废物库的安全管理水平,确保库区辐射环境安全和库内放射源实体安全,对2016—2021年四川省城市放射性废物库的库区环境监测结果进行了分析。分析表明：库区的γ辐射剂量率满足《核技术利用放射性废物贮存库选址、设计与建造技术要求》(试行)的要求,库区表面污染水平满足《电离辐射防护与辐射源安全基本标准》(GB 18871—2002)的规定,库区气溶胶历年监测数据一致性较好。此外,库区完善的安防措施为库区的安全运行提供了有力保障。四川省城市放射性废物库的运行未对库区环境造成不良影响,库区辐射环境质量良好。废物库的运行状态良好,库区辐射安全可控,其安全运行对保障全省核技术利用产业的发展和辐射环境的安全起到了重要作用。     

Analysis on the influence of forest soil characteristics on radioactive Cs infiltration and evaluation of residual radioactive Cs on surfaces

We investigated the depth profiles of radioactive Cs, ignition loss, and cation exchange capacity (CEC) in five types of forest soils sampled using scraper plates. We then simulated the monitored depth profiles in a compartment model, taking ignition loss as a parameter based on experimental results showing a positive correlation between ignition loss and the CEC. The calculated values were comparable with the monitored values, though some discrepancy was observed in the middle of the soil layer. Based on decontamination data on the surface dose rate and surface contamination concentration, we newly defined a surface residual index (SRI) to evaluate the residual radioactive Cs on surfaces. The SRI value tended to gradually decrease in forests and unpaved roads and was much smaller in forests and on unpaved roads than on paved roads. The radioactive Cs was assumed to have already infiltrated underground 18 months after the nuclear power plant accident, and the sinking was assumed to be ongoing. The SRI values measured on paved roads suggested that radioactive Cs remained on the surfaces, though a gradual infiltration was observed towards the end of the monitoring term. The SRI value is thought to be effective in grasping the rough condition of residual radioactive Cs quickly at sites of decontamination activity in the field. The SRI value may be serviceable for actual contamination works after further research is done to elucidate points such as the relation between the SRI and the infiltration of radioactive Cs in various types of objects.     

Composite use of numerical groundwater flow modeling and geoinformatics techniques for monitoring Indus Basin aquifer, Pakistan

The integration of the Geographic Information System (GIS) with groundwater modeling and satellite remote sensing capabilities has provided an efficient way of analyzing and monitoring groundwater behavior and its associated land conditions. A 3-dimensional finite element model (Feflow) has been used for regional groundwater flow modeling of Upper Chaj Doab in Indus Basin, Pakistan. The approach of using GIS techniques that partially fulfill the data requirements and define the parameters of existing hydrologic models was adopted. The numerical groundwater flow model is developed to configure the groundwater equipotential surface, hydraulic head gradient, and estimation of the groundwater budget of the aquifer. GIS is used for spatial database development, integration with a remote sensing, and numerical groundwater flow modeling capabilities. The thematic layers of soils, land use, hydrology, infrastructure, and climate were developed using GIS. The Arcview GIS software is used as additive tool to develop supportive data for numerical groundwater flow modeling and integration and presentation of image processing and modeling results. The groundwater flow model was calibrated to simulate future changes in piezometric heads from the period 2006 to 2020. Different scenarios were developed to study the impact of extreme climatic conditions (drought/flood) and variable groundwater abstraction on the regional groundwater system. The model results indicated a significant response in watertable due to external influential factors. The developed model provides an effective tool for evaluating better management options for monitoring future groundwater development in the study area.     

A long term study of the desiccation resistance of Drosophila melanogaster and D. simulans from the Mexican nuclear power plant “Laguna Verde”

The generation of electricity through the use of radioactive material at the nuclear power plant is inevitably associated with the production of wastes, some of which have potential impact on the biosphere. The objective of the present investigation was to provide information for evaluating the presumed impact of the Mexican Nuclear Power Plant “Laguna Verde" on the natural populations. Two sibling species that live in the immediate vicinity, Drosophila melanogaster and D. simulans have been studied for several traits in a long term study. The present study describes results for the desiccation resistance (DR) trait obtained during the period from 1995 to 2002. Flies were collected at two sites, one near the reactors and another farther away. The data obtained confirmed that D. melanogaster had higher DR values than D. simulans at both sites. The analysis of the results obtained from both species of the site closer to the reactor indicated that the values of the DR in the operational stage did not change, compared with those in the preoperational stage previously analyzed. Therefore, the significant differences found between the monitored sites did not seem to be associated to the operation of the reactors. L. Levine Died June 14th 2006     

江苏省核辐射突发事件的预警监测体系

核辐射突发事件的监测预警体系是环境突发公共事件应急管理体系的重要组成部分,对保障核与辐射安全具有重要的意义.介绍了江苏省核辐射突发事件的监测预警体系和辐射监测网络的建设现状,通过对国际辐射预警和监测技术的广泛调研,结合江苏省实际情况,分析应对核辐射突发事件的监测预警体系存在的问题和对策,提出了相应的建设规划和建议.     

Estimating contaminant attenuation half-lives in alluvial groundwater systems

One aspect of describing contamination in an alluvial aquifer is estimating changes in concentrations over time. A variety of statistical methods are available for assessing trends in contaminant concentrations. We present a method that extends trend analysis to include estimating the coefficients for the exponential decay equation and calculating contaminant attenuation half-lives. The conceptual model for this approach assumes that the rate of decline is proportional to the contaminant concentration in an aquifer. Consequently, the amount of time to remove a unit quantity of the contaminant inventory from an aquifer lengthens as the concentration decreases. Support for this conceptual model is demonstrated empirically with log-transformed time series of contaminant data. Equations are provided for calculating system attenuation half-lives for non-radioactive contaminants. For radioactive contaminants, the system attenuation half-life is partitioned into the intrinsic radioactive decay and the concentration reduction caused by aquifer processes. Examples are presented that provide the details of this approach. In addition to gaining an understanding of aquifer characteristics and changes in constituent concentrations, this method can be used to assess compliance with regulatory standards and to estimate the time to compliance when natural attenuation is being considered as a remediation strategy. A special application of this method is also provided that estimates the half-life of the residence time for groundwater in the aquifer by estimating the half life for a conservative contaminant that is no longer being released into the aquifer. Finally, the ratio of the half-life for groundwater residence time to the attenuation half-life for a contaminant is discussed as a system-scale retardation factor which can be used in analytical and numerical modeling.     

基于数值模拟的青岛市O3快速来源解析

为了建立臭氧污染快速来源解析方法,提高解析结果的时空分辨率,以2017、2018年青岛市环境空气质量精细化管理实践为契机,利用CAMx-OSAT模型的污染源识别与追踪技术,预测解析未来时段特别是污染期间不同区域、行业的排放源对目标站点O3浓度的贡献量和贡献率。结果显示:模拟的春、夏季2个时段青岛市的O3来源主要为工业、电厂、交通、生活源,2个时段的模拟结果本地和外来源中工业源的贡献分别占62. 0%和65. 0%,交通源分别占24. 5%和16. 0%,生活源分别占8. 4%和8. 0%,电厂源分别占5. 0%和11. 0%,O3高浓度污染时,工业源的贡献上升明显,青岛市的O3浓度外来源的贡献约占40%~80%。该数值模型O3来源解析及预测方法已成功用于青岛市的空气质量精细化管理及应急管控。     

Mechanistic Virtual Modeling: Coupling a Plant Simulation Model with a Three-dimensional Plant Architecture Component

The aim of this research is to integrate plant architectural modeling or “visualization modeling” and “mechanistic” or physiologically based modeling to describe how a real plant functions using a virtual crop. Virtual crops are life-like computer representations of crops based on individual plants and including the representation of the substrate on which the plants grow. The integration of a three-dimensional expression and the mechanistic model of plant development and growth requires the knowledge of the position of the organs along the different plant axes (the topology), their sizes, their forms, and their spatial orientation. The plant simulation model simulates the topology and organ weight or length. The superposition of spatial position and the topology produces the architecture of the plant. The association between sizes and organs creates what we refer to as the plant morphological model. Both components, the architectural model and the morphology model, are detailed in this paper. Once the integration is complete, the system produces a movie-like animation that shows the plant growing. The integrated model may simulate one or several plants growing simultaneously (in parallel). Visual capabilities make the proposed system very unique as it allows users to judge the results of the simulation the same way a farmer judges the situation of the crops in real life, by visually observing the field.     

保障辐射环境安全的放射源在线监控管理系统

利用集固定源及移动源等自动监控仪器和移动GPRS监控数据的采集、传输、存储、展示、统计及应用的综合业务平台,通过环保系统内部的业务协同,有效地获取放射源动态业务信息,可以提高核与辐射环境监管工作的信息化水平和对辐射污染事件的快速反应能力,为核与辐射环境管理提供服务.     

Inverse Modeling for Aquatic Source and Transport Parameters Identification and its Application to Fukushima Nuclear Accident

Inverse modeling technique based on nonlinear least square regression method (LSRM) is developed for the identification of aquatic source and transport parameters. Instantaneous line source release model in two-dimensional domain and continuous point source release model in three-dimensional domain are used for the purpose. Case studies have been carried out for both types of releases to illustrate their application. Error analysis has been carried out to identify the maximum error that can be tolerated in the input concentration data used in the inverse model and to specify the minimum number of sampling points to generate such input data. The LSRM is compared with the well-established correlation coefficient optimization method for instantaneous line source release model, and good comparison is observed between them. The LSRM is used to quantitatively estimate the releases of different radionuclides into the Pacific Ocean which has resulted due to the discharge of highly radioactive liquid effluent from the affected Daiichi Nuclear Power Station at Fukushima in Japan. The measured concentrations of these radionuclides in seawater samples collected from two sampling points near Fukushima are used for the estimation. The average release works out to be 1.09?×?10¹⁶ for ¹³¹I, 3.4?×?10¹⁵ Bq for ¹³⁴Cs, and 3.57?×?10¹⁵ Bq for ¹³⁷Cs. Very good agreement is observed between the releases estimated in this study and those estimated by other different agencies.