On a simplified system for steam production in nuclear power plants with pressurized water reactors

The paper develops the idea of a new system of steam production (Simplified System for Steam Production, SSSP) in nuclear power plants (NPPs) with PWR reactors, which is simplified as compared to the system used in the classical NPP of this type where steam is produced by steam generators (SGs). With the SSSP, expanders are used instead of SGs. The particularities of a NPP with a SSSP are analyzed in comparison to the classical NPP equipped with PWR and BWR reactors, which are used almost exclusively at present to produce electric energy at the industrial level.     

Using next generation nuclear power reactors for development of a techno‐economic model for hydrogen production

Nuclear and hydrogen are considered to be the most promising alternatives energy sources in terms of meeting future demand and providing a CO?‐free environment, and interest in the development of more cost‐effective hydrogen production plants is increasing—and nuclear‐powered hydrogen generation plants may be a viable alternative. This paper is a report on investigating the application of new generation nuclear power plants to hydrogen production and development of an associated techno‐economic model. In this paper, theoretical and computational assessments of generations II, III+, and IV nuclear power plants for hydrogen generation scenarios have been reported. Technical analyses were conducted on each reactor type—in terms of the design standard, fuel specification, overnight capital cost, and hydrogen generation. In addition, a theoretical model was developed for calculating various hydrogen generation parameters, and it was then extended to include an economic assessment of nuclear power plant‐based hydrogen generation. The Hydrogen Economic Evaluation Program originally developed by the International Atomic Energy Agency was used for calculating various parameters, including hydrogen production and storage costs, as well as equity, operation and maintenance (O&M), and capital costs. The results from each nuclear reactor type were compared against reactor parameters, and the ideal candidate reactor was identified. The simulation results also verified theoretically proven results. The main objective of the research was to conduct a prequalification assessment for a cogeneration plant, by developing a model that could be used for technical and economic analysis of nuclear hydrogen plant options. It was assessed that high‐temperature gas‐cooled reactors (HTGR‐PM and PBR200) represented the most economical and viable plant options for hydrogen production. This research has helped identify the way forward for the development of a commercially viable, nuclear power‐driven, hydrogen generation plant.     

地热流体开发利用中防垢除垢技术研究进展

地热流体结垢是阻碍地热资源稳定、经济和高效开发利用的因素之一。系统总结了中高温地热流体开发利用中防垢除垢技术研究进展。中高温地热田中代表性垢物是钙垢和硅垢,其中钙垢成分以CaCO₃为主,多形成于因压力下降导致CO₂脱气的开采井或者地面设备,硅垢成分以无定型SiO₂为主,多形成于因温度下降导致的溶解度减小的回灌井或者地面设备。实际生产中防垢除垢技术应结合地热流体利用方式进行选择和优化,直接利用方式可考虑采用基于CaCO₃和无定型SiO₂热力学性质的防垢技术;发电方式中钙垢可考虑阻垢剂注入的防垢技术,而硅垢则考虑利用石英和无定型SiO₂溶解度差异、调控温度、pH、无定型Si O₂浓度等防垢技术。     

紫外光液相光化学法分解硫化氢制氢

采用波长为253.7 nm的紫外光为光源,以Na2S溶液为反应液,进行了紫外光液相光化学法分解硫化氢(H2S)制氢反应。考察了S的存在形式、Na2S溶液的浓度、Na2SO3溶液浓度及H2S通入流量对制氢的影响。研究结果表明,溶液中S以HS-的形式存在有利于紫外光的分解;加入Na2SO3可以提高体系的产氢量;在体系中通入H2S可以使产氢速率保持稳定。     

高比例可再生能源渗透下多虚拟电厂多时间尺度协调优化调度

考虑可再生能源出力、电力负荷和电价等一系列不确定性因素,提出了高比例可再生能源渗透下的多虚拟电厂日内两阶段优化调度模型.该模型通过对多虚拟电厂中运行设备小时级时间尺度和分钟级时间尺度的协调优化,达到分级消除系统中随机和扰动因素的影响,实现高比例可再生能源的安全消纳.并且在多虚拟电厂优化调度模型中,借助Markowitz...     

基于时空图卷积神经网络的光伏发电功率超短期预测方法

为了解决传统光伏电站超短期功率预测方法不能同时准确提取发电功率的时间和空间特征的问题,提出一种基于时空图卷积神经网络的光伏发电功率超短期预测方法。针对同一区域内的多个光伏电站,首先对电站进行图建模,利用图卷积网络（GCN）与门控线性单元（GLU）提取发电功率的时空特征。利用提取到的时空特征信息以及区域内光伏电站的历史发电功率数据训练预测模型,最终实现对多个光伏电站发电功率超短期预测。实验结果表明,该方法能够将超短期功率预测均方根误差减小至1.122%,对工作人员根据实际情况进行电网的调度管理具有重要意义。     

考虑大规模风电接入的电力规划研究

由于风电出力的不确定性、反调峰性和风电场选址的限制等问题,大规模风电并网后要求电力系统留有更多的备用电源和调峰电源,且电网结构薄弱远距离输送能力有限,使得多数风电场出力无法被消纳,对系统的稳定运行、电源规划和电网规划等方面造成了很大的负面影响,阻碍了风电的规模化应用。分析了大规模风电接入对系统可靠性、系统备用以及运营成本等带来的挑战,从电力规划角度回顾和评述了国内外风电接入系统在电源规划、电网规划以及电源电网协调规划等领域的研究进展和研究现状,明确了该领域的研究重点和研究方向。     

A simple method to compute hydrogen chloride abatement in geothermal power plants

One of the most important problems affecting geothermal fields is the abatement of hydrogen chloride contained in the vapor phase. If the chloride concentration exceeds a few ppmw, steam scrubbing must be provided in order to prevent corrosion of the gathering system and turbine failure. In some fields at Larderello, one of the most important geothermal areas in Italy, steam scrubbing is performed by injecting a caustic solution directly into the steam pipeline. In particular, the abatement system depends on absorption with chemical reaction of hydrogen chloride by a sodium hydroxide solution. This paper describes some of the Larderello power plant abatement systems and presents analyses of the different solutions adopted for this purpose. Finally, some simplified models for computing abatement efficiency in sprays, pipelines, static mixers, cyclones and vane type demisters—the equipment generally used in these plants—are proposed. The proposed models are able to predict the data measured in these power plants with good accuracy, and so they can be regarded as useful tools for designing new abatement systems or optimizing the existing ones.     

Econometric modelling of certain nuclear power systems based on thermal and fast breeder reactors

Certain known economic analysis models for a LMFBR fast breeder and CANDU thermal solitary reactors are processed in this work, based on the concepts of discounting and levelization. These models are subsequently utilized as a basis for establishing an original model for the econometric analysis of certain thermal reactor systems or/and fast breeder reactors, considering techniques of scaling escalation and mediation of the components of the levelized present specific generation cost. The applied formalism is that of the constant monetary units as compared to the zero year of the interval under analysis which is based on the assumption that the inflation effects are excluded. Case studies are subsequently conducted with the systems: 1-CANDU, 2-LMFBR, 3-CANDU + LMFBR which enables us to draw certain interesting conclusions for a long range nuclear power policy.     

Analysis of earthquake management design for nuclear power plants (NPPs) incorporated with artificial intelligence (AI) method

It has been studied to analyze the operations in nuclear power plants (NPPs) where the human error could make a trigger to the nuclear disaster following the earthquake in South Korea. The earthquake warning system and its related control algorithm are modeled by the machine learning (ML) of artificial intelligence (AI) where the neural networking is done as a major role. The AI-based control system could give the very good performance in the earthquake incident which is shown by the system dynamics (SD) based simulations. Hence, the nuclear safety system needs the AI based alarming technology which could be a much more advanced control system incorporated with the conventional multiple-barrier concept in NPPs.     

Natural circulation with DOWTHERM RP and its MARS code implementation for molten salt‐cooled reactors

Recently, molten salt has received attention as a promising coolant for advanced nuclear reactors, especially for fluoride salt‐cooled high‐temperature reactor. The heat transfer characteristics of molten salt provide great advantages for application as a primary coolant, because of its superior performance in terms of sustainability, economics, safety, and reliability compared with gas coolant. However, understanding the thermal‐hydraulic characteristics of molten salts by experimental method is difficult because of its high‐temperature corrosion and toxicity issue. Therefore, oil fluids were introduced as simulants for studying the heat transfer phenomena of high Pr (Prandtl number) molten salts. In this study, a scaled‐down experiment using simulant oil was conducted, and scaling laws were applied to investigate a single‐phase natural circulation, which is important in nuclear reactors as a part of their passive safety. DOWTHERM RP (Diaryl Alkyl) was considered as a heat transfer simulant in this study because it matches the relevant dimensionless numbers (Prandtl number, Ra, Grashof number, Reynolds number, etc.) with those of molten salt. Prior to the experiment, the thermophysical properties of both the liquid and vapor phases of DOWTHERM oils were implemented into thermal‐hydraulic system analysis code or multi‐dimensional analysis of reactor safety code, to enable simulation and further study of the molten salts. Then, natural circulation experiments were conducted with the scaled rectangular loop, to establish similarity and experimental feasibility. For the validation, two different codes (multi‐dimensional analysis of reactor safety and computational fluid dynamics (CFD) were used to simulate the same natural circulation loop. From the experimental data, new heat transfer correlation for a single‐phase natural convection was developed, and the existing heat transfer correlations were compared. Copyright © 2016 John Wiley & Sons, Ltd.     

Gas explosion field test with release of hydrogen from a high pressure reservoir into a channel

Field experiments of a high pressure release of hydrogen gas inside a 6 m long, 0.9 m wide, and 0.8 m high channel have been performed, to validate the Froude scaling and to obtain pressure and flame speed data in an inhomogeneous hydrogen–air cloud. Froude scaling with a length scale corresponding to the height of a 100% hydrogen layer in the channel was used to describe the flow of the hydrogen–air cloud in the channel. The estimated time of ignition based on the Froude scaling for release pressures of 100 bars and 150 bars agreed well with the experiments. At lower release pressures the estimated time was lower, which was most likely caused by dilution of the front of the hydrogen cloud. High speed video was used to record the flame speed. For the present experimental conditions it appeared that the deflagration taking place closer to the jet source determines the maximum explosion pressure.     

高含硫管线冬季冻堵情况分析

冬季天然气输送过程中，忠县采输气作业区高含硫集气管线宝1井至池50井多次发生冻堵现象，降低了输送能力。其原因主要是由于该管线内径较小，集气支线较长，天然气H2S含量较高造成的。可采取加注防冻剂、放空泄压、清管通球的方法保证该管线的正常运行。其中防注剂加注量宜控制在6．9-7．8kg（乙二醇浓度为65％-70％），并适当调节加注流量、延长加注时间，实行连续加注。清管通球的次数可定为每月3～4次。     

Uniform Bi2S3 nanorods-assembled hollow spheres with excellent electrochemical hydrogen storage abilities

Hierarchical Bi₂S₃ hollow spheres have been synthesized by a facile solvothermal process in the presence of sodium tartrate. The hollow spheres are composed of numerous ultrathin nanorods with the average diameter of 15 nm. Based on the time dependent electron microscope observations, the formation mechanism of such hierarchical structures has been proposed as a sodium tartrate directed self-assembled process and oriented attachement mechanism. The morphology and size of the subunits can be controlled by adjusting the amount of sodium tartrate. The Nitrogen adsorption-desorption measurements suggest that mesopores exist in these hollow spheres. The as-derived Bi₂S₃ hollow spheres exhibit excellent electrochemical hydrogen storage properties.     

A novel method for producing hydrogen from water with Fe enhanced by HS under mild hydrothermal conditions

In this paper, a novel method for producing hydrogen from water with Fe as a reductant promoted by HS⁻ under mild hydrothermal conditions was proposed. Results showed that hydrogen production significantly increased in the presence of HS⁻ compared to that in the absence of HS⁻. The obvious hydrogen production was achieved in a low reaction temperature of 250 °C and a very short reaction time (less than 2 h). The maximum yield of hydrogen production, which was defined as the percentage of produced hydrogen amount to theoretical one according to completive oxidation of Fe to Fe₃O₄ to produce hydrogen from water, was 34% at 300 °C. HS⁻ may act as a catalyst and a possible HS⁻-catalyzed mechanism was proposed. This process may provide a promising solution for biomass-driven hydrogen production from water combined with the process of reducing iron oxide into their zero-valent state by bio-driven chemicals, such as glycerin.     

Hierarchical chlorophytum-like Bi2S3 architectures with high electrochemical performance

Hierarchical chlorophytum-like Bi₂S₃ nanostructures are produced successfully on the large scale by a solvothermal method in the mixture of water and tetrahydrofuran. The crystal structure and morphology of the product are determined by X-ray diffraction (XRD) pattern, field emission scanning electron microscope (FESEM), and transmission electron microscopy (TEM). Time-dependent SEM observations indicate that the structure evolution of Bi₂S₃ contains self-assembly process and anisotropic growth mechanism. Furthermore, the electrochemical measurements present that the hierarchical Bi₂S₃ architectures display high electrochemical hydrogen storage and electrochemical Li intercalation performance.     

Green hydrogen: A new flexibility source for security constrained scheduling of power systems with renewable energies

Green hydrogen, i.e. the hydrogen generated from renewable energy sources (RES) will significantly contribute to a successful energy transition. Besides, to facilitate the integration and storage of RES, this promising energy carrier is well capable to efficiently link various energy sectors. By introduction of green hydrogen as a new flexibility source to power systems, it is necessary to investigate its possible impacts on the generation scheduling and power system security. In this paper, a security-constrained multi-period optimal power flow (SC-MPOPF) model is developed aiming to determine the optimal hourly dispatch of generators as well as power to hydrogen (P2H) units in the presence of large-scale renewable energy sources (RES). The proposed model characterizes the P2H demand flexibility in the proposed SC-MPOPF model, taking into account the electrolyzer behavior, reactive power support of P2H demands and hydrogen storage capability. The developed SC-MPOPF model is applied to IEEE 39-bus system and the obtained numerical results demonstrate the role of P2H flexibility on cost as well as RES's power curtailment reduction.     

结构型载氧体固定床化学链重整制氢的实验研究

采用浸渍法制备球形与拉西环形两种不同结构型Ni基载氧体,用于甲烷化学链重整制氢反应。在固定床中考察反应温度、进气水碳物质的量的比和空速对载氧体活性及稳定性的影响,并对比研究两种不同结构型载氧体的性能。结果表明：两种载氧体均可以保持较好的活性,相对而言球形载氧体更易积碳。在800℃以上时两种载氧体均具有较高的甲烷转化率及产物选择性,拉西环形载氧体在高温下性能下降得较慢。过高的水碳物质的量的比会抑制重整反应的进行,但拉西环形载氧体在高水碳物质的量的比下仍能保持较高的产物选择性。随着空速的增大,拉西环形载氧体的甲烷转化率降低,而对球形载氧体来说,当空速在3 500 h^-1左右时甲烷转化率和氢气产率均最高。经过20次循环稳定性测试,两种载氧体颗粒均出现了不同程度的积碳烧结,其中拉西环形载氧体结构保持得较好,积碳在氧化阶段能被部分清除。     

Study of an indian biogas plant with a water pond

To overcome the problem of reduced biogas production, due to low ambient temperatures during the winter months of northern India, a novel concept of a shallow solar pond (SSP) water heater has been put forward and studied theoretically. The pond is proposed to be integrated with the dome of the conventional Indian (KVIC) biogas design. The results of the study show that system is capable of providing hot water upto a temperature of 40°C which, in turn, can be used for hot charging of the slurry besides reducing the heat losses from slurry to the ambient. Simultaneously, it helps in enhancing the slurry temperature from 20°C to 27°C.     

Comparison between Current Technologies for the Best Choice of Thermoelectric Plant with Coal or Uranium

Between the alternative sources available for the electricity production, still lacks reliability for the production in base units. For the electricity production from 500 MW to 1,000 MW or more, the coal-fired thermal and nuclear power plants with uranium have proved competitive and with a high level of reliability and maturation, besides presenting the fuel supply security. This paper presents an analysis of technical feasibility for the choice of the best technology for generating electricity on a large scale, based on coal-fired thermal or nuclear power plant using uranium. This paper takes in account the availability of fuel sources, investments costs, thermal power generation systems, pollutants emission and mitigation technologies, global efficiency, fuel consumption, costs of electricity, construction time and an average lifespan of the installation. Thus the analysis allows the most rational choice of technology for the production of electricity with lower electricity costs and lower COz emissions.