From conventional nuclear power reactors to accelerator-driven systems

Due to many factors, there is again increase in trend to use the nuclear power for energy production. But spent fuel from nuclear power plants has become one of the crucial problems of nuclear energy exploitation. Some problems attributed to the conventional nuclear power reactors along with their solutions and a historical transition from nuclear power reactors to accelerator-driven systems are briefly reviewed in the present work. It is argued that accelerator-driven systems (ADS), for transmutation of nuclear waste and energy production, are good alternatives to the conventional nuclear power plants. Important differences between the conventional nuclear reactors and the ADS along with the ADS physics are discussed. The ADS is considered to be relatively safe as compared to the other nuclear power reactors commonly in use.     

核电扩建工程中的安全管理

近年来,我国的核电站建设处于快速发展时期,核电站建设过程中项目繁多,容易发生事故,所以建设过程的安全生产问题尤为重要。文章根据某项目部安全管理工作的实际内容,结合安全相关的理论基础,对核电站建设过程中的安全生产管理进行了探讨。描述了某扩建工程项目部的部分安全管理工作,利用系统安全方法进行施工过程中的危险源管理。     

Modular design and construction techniques for nuclear power plants

Modularization has been proposed as a nuclear power plant design-fabrication approach for increasing the quality and reducing the costs of future plants. The work reported describes a methodology for making the modular design and construction process more systematic and efficient. This methodology is applied to both the design and fabrication processes for power plant modules. The design process is enhanced by the utilization of a matrix reordering technique that reveals natural groupings in complex data sets. This technique allows a layout which groups plant systems functionally so that modules increase self-sufficiency and minimize inter-module interaction costs.In an illustration of modular design the ship fabrication methods of product work breakdown structure are applied to a modular nuclear power plant to be built at an on-site factory facility. A comparison of a new modular power plant and a conventional power plant design is performed. Cost penalty indices are defined in order to guide maximization of the economic benefits of a modular design. Economic analyses, for both modular and conventional construction methods, are performed over a range of construction schedules and monetary interest rates to illustrate the potential savings of modular construction. The results of the analyses reported here indicate a typical potential savings of 15% in the capital cost of the modular nuclear power plant versus a conventional one. The most interesting result of this work is that the potential savings derive equally from the design and construction processes.     

The role of nuclear power in the sustainable energy future of Korea

The purpose of this study is to analyze the role of nuclear power in the sustainable energy supply future of Korea. For this purpose, an energy-economy interaction model of the computational general equilibrium (CGE) approach, the Korean Energy and Environmental Policy model(KEEP) was adapted. The model is a non-linear optimization model that maximizes the discounted value of Korean economic utility. The model operates over the time horizon of 1995–2040 in annual steps.

Some scenarios are established in accordance with three possible nuclear growth rate and the strength of the carbon tax imposed. At first, business as usual(BAU) nuclear growth scenario was set up and maintaining the current installed capacity and phasing out the nuclear power options are considered. After that, the investigation has been done on each scenario in the case that a tax for CO₂ emission regulation was imposed.

Results show that limiting CO₂ emissions with a nuclear phase out scenario will have the most serious impact on the economic welfare compared with the other scenarios. If the CO₂ emission target will be imposed in Korea in the foreseeable future, nuclear power will play an important role in mitigating the economic impacts.

This analysis gives us a chance to consider the trade-offs between the most important energy issues of today-concerns with the risk of nuclear power, those involving future climate change, and energy security.     

Simultaneous and multi-criteria optimization of TS requirements and maintenance at NPPs

One of the main concerns of the nuclear industry is to improve the availability of safety-related systems at nuclear power plants (NPPs) to achieve high safety levels. The development of efficient testing and maintenance has been traditionally one of the different ways to guarantee high levels of systems availability, which are implemented at NPP through technical specification and maintenance requirements (TS&M). On the other hand, there is a widely recognized interest in using the probabilistic risk analysis (PRA) for risk-informed applications aimed to emphasize both effective risk control and effective resource expenditures at NPPs. TS&M-related parameters in a plant are associated with controlling risk or with satisfying requirements, and are candidate to be evaluated for their resource effectiveness in risk-informed applications. The resource versus risk-control effectiveness principles formally enter in optimization problems where the cost or the burden for the plant staff is to be minimized while the risk or the availability of the safety equipment is constrained to be at a given level, and vice versa. Optimization of TS&M has been found interesting from the very beginning. However, the resolution of such a kind of optimization problem has been limited to focus on only individual TS&M-related parameters (STI, AOT, PM frequency, etc.) and/or adopting an individual optimization criterion (availability, costs, plant risks, etc.). Nevertheless, a number of reasons exist (e.g. interaction, similar scope, etc.) that justify the growing interest in the last years to focus on the simultaneous and multi-criteria optimization of TS&M. In the simultaneous optimization of TS&M-related parameters based on risk (or unavailability) and cost, like in many other engineering optimization problems, one normally faces multi-modal and non-linear objective functions and a variety of both linear and non-linear constraints. Genetic algorithms (GAs) have proved their capability to solve these kinds of problems, although GAs are essentially unconstrained optimization techniques that require adaptation for the intended constrained optimization, where TS&M-related parameters act as the decision variables. This paper encompasses, in Section 2, the problem formulation where the objective function is derived and constraints that apply in the simultaneous and multi-criteria optimization of TS&M activities based on risk and cost functions at system level. Fundamentals of a steady-state GA (SSGA) as an optimization method is given in Section 3, which satisfies the above requirements, paying special attention to its use in constrained optimization problems. A simple case of application is provided in Section 4, focussing on TS&M-related parameters optimization for a stand-by safety-related system, which demonstrates how the SSGA-based optimization approach works at the system level, providing practical and complete alternatives beyond only mathematical solutions to a particular parameter. Finally, Section 5 presents our conclusions.     

基于FDS的核电厂主储油罐间防火阀响应控制效用模拟研究

通过应用火灾动力学软件FDS,建立了一套核电厂主储油罐间防火阀响应与失效两种状态下的对比模型,讨论了烟气形态、火焰形态、火源热释放速率及火灾温度场随时间的变化规律。研究表明,防火阀对于核电厂主储油罐间火灾事故的控制效果非常明显,通过火灾封锁法能够有效控制火源热释放速率,降低环境温度,体现了FDS应用在核电厂火灾预防方面的优势。     

Use of a fuzzy decision-making method in evaluating severe accident management strategies

In developing severe accident management strategies, an engineering decision would be made based on the available data and information that are vague, imprecise and uncertain by nature. These sorts of vagueness and uncertainty are due to lack of knowledge for the severe accident sequences of interest. The fuzzy set theory offers a possibility of handling these sorts of data and information. In this paper, the possibility to apply the decision-making method based on fuzzy set theory to the evaluation of the accident management strategies at a nuclear power plant is scrutinized. The fuzzy decision-making method uses linguistic variables and fuzzy numbers to represent the decision-maker's subjective assessments for the decision alternatives according to the decision criteria. The fuzzy mean operator is used to aggregate the decision-maker's subjective assessments, while the total integral value method is used to rank the decision alternatives. As a case study, the proposed method is applied to evaluating the accident management strategies at a nuclear power plant.     

Seismic risk analysis and decisions for nuclear power plants

Seismic risk analysis and associated sensitivity studies constitute a part of the Seismic Safety Margins Research Program being conducted by the Lawrence Livermore National Laboratory for the US Nuclear Regulatory Commission. Although seismic risks are an important contributor to the total nuclear risk, the occurrence of earthquake-related seismic phenomena is low. Safety decisions involving seismic hazards must be made, however. This paper briefly described several categories of decisions that can be made using seismic risk analysis. While risk analysis does not provide all the information required for these decisions, it is a useful tool in that it provides additional information for the decision-making process. We anticipate a growing interest in the use of seismic risk analysis in nuclear safety evaluations.     

重水堆机组大修的核安全风险控制

重水堆机组大修期间核燃料仍保持在堆芯,同样存在反应堆意外临界、堆芯余热不能正常导出引起燃料元件损坏等核安全风险,而且这种风险还由于停堆大修期间核电站系统配置薄弱、交叉作业多等因素而增加.文章分析了秦山三厂典型的大修关键路径安排中存在较大核安全风险的几个阶段,并介绍了在历次大修中结合重水堆机组特点所采取的一系列核安全风险管控措施,以确保机组大修期间的核安全.     

Ecology and stable development of the region containing the novovoronezh nuclear power plant

Risk analysis applied to public health is used to evaluate the ecological safety of the territory of Voronezh Oblast, where the Novovoronezh nuclear power plant is located and a new plant is under construction. It is found that for the population of the territory of Voronezh the individual risk of developing cancer because of the contamination of air by chemical carcinogens and the risk of death due to pollutants are 1000–10000 times higher than the risk of developing cancer from the additional irradiation of the population of Novovoronezh associated with the operation of the nuclear power plant. The results obtained showed that modern nuclear technologies have no effect on the public health as compared with sources of chemical risk.     

Analysis of human-induced initiating events in a multi-unit loss of offsite power scenario

ABSTRACT

Human-induced initiators (category-B actions) are the initiators that are caused by human errors and are rarely explicitly identified and modeled in probabilistic safety assessments (PSAs). The current concern over the safety of multi-unit nuclear power sites is also a motivation for this research. This study proposes a novel process for identifying and quantifying category-B actions and ultimately, how to derive a human-induced initiating event frequency in a multi-unit scenario. Hence, this study fundamentally applies a scenario–system–action search scheme using maintenance and testing procedures, quantifies the human error probability by using the cause-based decision tree and technique for human error rate prediction method, models category-B human actions in the developed fault trees, and derives the human-induced initiating event frequency. The procedure, which is used in this approach, essentially involves system analysis, fault tree development, human error identification, screening, and quantification. The multi-unit loss of offsite power is used as an example accident situation which illustrates the application of the suggested method. Hence, the human-induced initiating event frequency for the loss of off-site power scenario for two units is derived. The application of this method would advance the efforts concerning multi-unit nuclear power plant (NPP) site risk analysis.     

核电厂事故核素扩散有效剂量影响因子模拟研究

介绍了核电厂事故后果评价影响因素模拟分析方法,以某内陆核电厂址为研究对象,应用核电厂事故后果计算程序模拟了不同扩散参数和源项变化情景下核电厂事故短期大气弥散因子和有效剂量对其响应特征。结果表明,水平扩散参数情景下短期大气弥散因子的最大值发生频率相对于垂直扩散参数情景较低,有效剂量最大值发生频率源项情景远高于扩散参数情景,有效剂量对扩散参数的响应程度要比对源项变化的响应程度要高。多种因子对核电厂核素大气扩散特征的综合效应还需进一步研究。     

Structural damping values as a function of dynamic response stress and deformation levels

The development of extreme load design criteria both as to rate and depth within any national jurisdiction as applied to nuclear power plant design is a function of several factors. The prime factor is the number of nuclear power plant facilities which are operating, under construction or planned in a given country. The second most important factor seems to be the degree of development of a domestic independent nuclear steam system supplier, NSSS vendor. Finally, countries whose domestic NSSS firms are active in the export market appear to have more active criteria development programs or at least they appear more visible to the foreign observer.For the purposes of this paper, extreme loads are defined as those loads having probability of occurrence less than 10⁻¹/yr and whose occurrence could result in radiological consequences in excess of those permitted by national health standards. The specific loads considered include earthquake, extreme wind (tornado), airplane crash, detonation, and high energy system rupture. The paper identifies five national centers for extreme load criteria development; Canada, Great Britian, USA, USSR, and West Germany with both France and Japan also about to appear as independent centers of criteria development. Criteria under development by each national center are discussed in detail.     

应急撤离模拟在核电厂道路方案优化中的应用北大核心CSCD

将概率风险评价方法应用于核电厂的应急撤离模拟,利用自主编写的简化撤离模拟程序,结合厂址事故源项、人口、道路、气象条件等特征,对多个核电厂应急撤离条件下公众与工作人员可能的受照剂量和风险进行了对比分析。在此基础上,结合霞浦厂址应急道路方案遇到的实际问题,在保证事故应急状态下公众和工作人员能够有效撤离的同时,对应急道路方案进行了比选,为工程的实施提供借鉴和参考。相关程序和方法也可为后续发展海岛核电、小型供热堆等提供技术支持,有助于更直观地开展核电公众沟通。     

Radiation doses to the public from the nuclear industry

Section 1: It is shown that the dangers arising from power production in the past were greater than those arising from any form of power production today. Section 2: The specific ways in which radiation injures both the present and future generations are described. Section 3: The routine risks arising from nuclear power production are compared with those arising from other modern sources; first the risks to those employed in power production and then the risks to the general public, including the risks arising from efforts to conserve energy. Section 4: The risks to the public arising from major accidents are explained. Section 5: The radiation risks incurred by the public in the course of medical diagnosis and treatment are described and discussed. Section 6: Conclusion. It is pointed out that the dangers of nuclear energy are considerably less than those of all other sources other than directly piped natural gas; and that the reduction of the specific risks due to ionizing radiation arising from medical uses and from domestic heat conservation could save about a hundred times as many lives as would the complete elimination of the radiation arising from the production of nuclear power.     

核电厂火灾PSA中火灾场景频率分析方法

核电厂的火灾场景频率分析是火灾概率安全分析的核心内容。本文根据美国NRC和EPRI的《核动力设施火灾概率风险评价方法》,介绍了核电厂内部火灾概率安全评价中,火灾场景频率的分析方法及参数不确定性的处理方法。以福清一期核电厂某房间的电气柜火灾为例,进行了定量分析计算,计算结果表明,在计算中考虑热释放速率参数不确定性的传递可以有效降低计算结果的保守性。     

Author index to volume 60

This paper summarizes the main findings of a comprehensive study of the underground siting of nuclear power plants carried out at the Swiss Federal Institute for Reactor Research. Main aim of the investigations made was to identify suitable siting variants and to evaluate the feasibility, the safety potential and the cost of the concept. Two of the layouts developed for the main siting alternatives — the rock cavity alternative and the pit siting — are briefly described. In these designs an accident mitigation system based on the pressure relief concept, meant to reduce the consequences for the public and the environment in the case of extreme hypothetical events, has been proposed and an evaluation of its performances has been made to quantify the achievable risk reduction. The safety potential — especially under accident conditions — of this type of siting and the possibility that an underground plant may be exposed to new accident initiating events have been evaluated.From the technical point of view, an underground nuclear power plant is considered feasible while the economic penalty associated with the underground siting lies between 11 and 15%, according to the considered alternative.     

核电站蒸汽发生器泄漏监测——氮-16辐射监测仪概述

蒸汽发生器是压水堆核电站核蒸汽供应系统的主要设备之一,对蒸汽发生器传热管进行泄漏监测关系到核电站的安全和经济运行。介绍了用于蒸汽发生器泄漏监测的氮-16辐射监测仪的概况、工作原理、系统组成等。     

AP1000核电厂厂外剂量风险定量化分析

为了分析AP1000核电厂各种潜在的严重事故对周围公众的影响,采用MACCS程序模拟释入大气中气载放射性物质的弥散过程,对6种代表性释放类别进行剂量风险定量化分析。计算结果表明,事故后24 h内厂址边界附近公众的急性红骨髓剂量风险为1.96×10^-7 Sv/（堆•年）,该风险大部分来自安全壳旁通释放(BP);早期健康效应风险在10^-10~10^-9 Sv/(堆•年),且随着与反应堆距离的增大降幅明显;集体全身有效剂量风险为6.94×10^-4 人•Sv/（堆•年）,引发的癌症致死风险非常低。研究结果还表明,核事故后及时撤离将显著降低公众剂量风险。     

秦山三期重水堆核电站技术创新实践

文章介绍了秦山第三核电有限公司消化吸收引进技术,坚持改进创新,提升重水堆核电机组综合性能;坚持自主科技攻关,实施汽轮机功率提升改造及深入开拓重水堆技术优势,大力推进重水堆钻-60生产、回收铀和钍资源利用技术开发。通过不断地科技创新和实施技术改造,核电站的安全性和可靠性也不断提高,核电站整体运营水平处于国际先进水平,取得了良好的经济效益、环境效益和社会效益。