Nuclear Power Plants In China Research Articles

Analysis of Discharge Faults Between Flanges Caused by Transient Enclosure Voltage

An increase in transient enclosure voltage can threaten the personal safety of workers and the normal operation of secondary equipment and may cause discharge between the flanges of gas insulated switchgear (GIS) enclosures. This study considered the spark–discharge fault between GIS enclosure flanges of a 500-kV nuclear power plant in China when the disconnect switch is operated in the background. The dynamic arc model during the operation of the disconnect switch was improved in this study, and the equivalent calculation model of transient enclosure voltage (TEV) caused by very fast transient overvoltage generated during the operation of the disconnect switch was established using the electromagnetic transient program ATP-EMTP. Suppression measures of the discharge phenomena were also discussed. The results demonstrated that the transient enclosure voltage caused by the operation of the disconnect switch can reach 75 kV in the most severe case, which causes discharge between the flanges. Reducing the residual charge on the island side of the disconnect switch, installing a metal oxide arrester, and reducing the inductance of the ground wire have different inhibitory effects on this discharge phenomenon, but they all have their limitations. The most simple and effective control measure is to use a short joint between two flanges. The study conclusions can be used as reference for preventing such discharge phenomena.

Industrial Application Research of Portable Video Recorder based on LabVIEW

In this paper, a portable test recorder is designed and manufactured. As an open test system, the recorder can be self-configuring according to the requirements of measurement tasks to realize the acquisition, analysis and processing of various equipment signals, to meet the needs of high-range, high-precision and multi-channel measurement. At the same time, the recorder has the advantages of compact, portable, wide application range, friendly man-machine. Interactive interface and flexible operation can meet the complex test environment in industrial field. The recorder has been applied to the test of 9020 series plates in a nuclear power plant in China. It provides accurate measurement basis for plate detection and solves the problem of high range and high precision of 9020 series plates in a nuclear power plant.

A CFD MODEL BASED ON WET DEPOSITION OF LARGE-SCALE NATURAL DRAFT COOLING TOWER

Traditional research on environmental impacts of natural draft cooling tower in nuclear power plant is mainly based on Gaussian diffusion model or wind tunnel experiments. With the development of modern mainframe computers and turbulence models, CFD method is possible to use for simulating plume drift. CFD software, as it owns powerful computing ability, can simulate and display the plume drift more accurately. In this paper, data from the 1977 Chalk Point Dye Tracer prove CFD simulation to be effective. Also, this paper provides case study on Taohuajiang and Pengze inland nuclear power plants in China. In conclusion, CFD result conforms with the data from the Chalk Point experiment. Compared with SACTI model. As down-wind distance increases, SACTI results decreases faster than CFD. This paper provides a solution that in the lack of field data, CFD will be a powerful tool for assessing environment impacts.

Thoughts on Decommissioning of Nuclear Power Plants in China

With the increasing of the numbers and operation years of the nuclear power plants in China, the decommissioning of nuclear power plants is becoming more and more important. The safe, economical and environment-friendly decommissioning is related to the sustainable development of the nuclear industry, as well as the safety of the ecological environment and the health of future generations. From the perspective of international nuclear decommissioning experience feedback and decommissioning market development and based on decommissioning related national planning in China, key tasks in the future decommissioning of nuclear power plants in China are proposed, including the completion of the decommissioning related codes and standard; Self-reliant, enterprization, marketization, and specialization road, cooperation and win-win strategy; the decommissioning related considerations of the whole life cycle of nuclear power plants, the acceleration of the R&D of decommissioning related key technology and equipment, and the provision of decommissioning funds.

Qualification Requirements Design for Neutron Absorber Plate for Spent Fuel Racks in Domestic Nuclear Power Plants

Boron carbide (B4C) particle-reinforced aluminum matrix composite is the key material for use as neutron absorber plate in fuel storage applications for Generation III advanced passive nuclear power plants in China. This material has once depended upon importing with various restrictions so that it has meaningful practical significance to realize the localized manufacturing for this material in China. More importantly, since it is the first time for this material to be used in domestic plant, particular care should be taken to assure the formal supplied products exhibit high stabilized and reliable service in domestic nuclear engineering. This paper initiates and proposes a principle design framework from technical view in qualification requirements for this material so as to guide the practical engineering application. Aiming at neutron absorber materials supplied under practical manufacturing condition in engineering delivery, the qualification requirements define B4C content, matrix chemistry, 10B isotope, bulk density, 10B areal density, mechanical property, and microstructure as key criteria for material performance. The uniformity assessment as to different locations of this material is also required from at least three lots of material. Only qualified material meeting all of the qualification requirements should proceed to be verified by lifetime testing such as irradiation, corrosion, and thermal aging testing. Systematic and comprehensive performance assessments and verification for process stabilization could be achieved through the above qualification. The long-term service for this neutron absorber material in reliable and safe way could be convincingly expected in spent fuel storage application in China.

An integrated framework for analysing operational events in China nuclear power plants

Operational events of nuclear power plants (NPPs) are safety-relevant incidents, which may impair the plant functionality and lead to undesired consequences. Thus, their analysis is important for the safety assessment of NPPs. Although several studies have been conducted on NPPs operational events, there is a lack of an integrated framework that effectively combines qualitative and quantitative analyses of operational events. In this study, a framework for the identification and quantification of root causes of operational events is proposed. The framework includes the root causes identification procedures and an online quantification tool based on Bayesian Network modeling. Thirty-seven unplanned reactor trip (URT) events occurred in Chinese NPPs have been used for the case study and the outcome indicates that this framework can be quite useful: on the one hand, it can support inspection and control of the measures of prevention of operational events and reduction of their occurrences from the perspective of regulatory authorities; on the other hand, it can be embedded within the national nuclear safety administration (NNSA) experience feedback (EF) system as an online support tool for living safety assessment.

Policies on water resources assessment of coastal nuclear power plants in China

Nowadays, all nuclear power plants including constructed ones and those under construction are coastal plants in China. Water resources assessment of coastal nuclear power plants in China is based on the Guidelines for Water Resources Assessment of Construction Projects (SL 322). However, the specific guideline for water resources assessment of coastal nuclear power plant projects, the Guidelines for Water Resources Assessment of Coastal Nuclear Power Plant Projects, has not yet issued at present. Based on the relevant laws, field trip, site survey, and operation experience of coastal nuclear power plants in China, technical points of water resources assessment for coastal nuclear power projects were analyzed, and contents of the guideline in China were put forward in the aspects of water usage rationality analysis, water source assessment, impact demonstration of water intake and drainage, etc.

Research on Water Intake, Usage and Drainage Impact Demonstration for Coastal Nuclear Power Plants

Nowadays, all nuclear power plants including constructed ones and those under construction are coastal plants in China. Water resources assessment of coastal nuclear power plants in China is based on the Guidelines for Water Resources Assessment of Construction Projects (SL 322). However, the specific guideline for water resources assessment of coastal nuclear power plant projects, the Guidelines for Water Resources Assessment of Coastal Nuclear Power Plant Projects, has not yet issued at present. According to the plans for intake, usage and discharge of water proposed by the owner of coastal nuclear power plants, it was proposed that the general requirements for water resources assessment by considering characteristics of intake, usage and discharge for water. In this study, Tianwan nuclear power plant was chose as the case study. Researches on yields of intake and usage of water, and the impact of water discharge for this nuclear power plant could provide the reference for water intake and usage rationalities, as well as the impact analysis caused by water discharge of coastal nuclear power plants.

我国核电站放射性化学废水的处理工艺

我国核电站放射性化学废水的处理工艺

Best-estimate calculation plus uncertainty analysis of SBLOCA transient for the scale-down passive test facility

CAP1400 has been developed as a new passive nuclear power plant in China based on AP1000 technique. In order to support the CAP1400 licensing, a scale-down integral test facility named ACME (Advanced Core-cooling Mechanism Experiment) has been designed and constructed. In this study, best-estimate calculation using RELAP5/MOD3.4 code plus uncertainty quantification and sensitivity analysis of the small break loss of coolant accident (SBLOCA) transient were carried out for the ACME test facility. The important thermal-hydraulic phenomena during the SBLOCA transient were investigated through the comparing calculations between the ACME and CAP1400. Thereafter, uncertainty quantification process was demonstrated including the selection of input uncertain parameters, the application of Wilks’ nonparametric statistics and the propagation of uncertainty through the SNAP interface coupling RELAP5 and DAKOTA codes. Furthermore, the results of uncertainty and sensitivity analysis were discussed. Through the comparison of the thermal-hydraulic modeling results between ACME and CAP1400, the results show that the ACME test facility is able to reproduce the important thermal-hydraulic phenomena of CAP1400 by reasonable scaling design. The 95/95 uncertainty bands of some key output parameters are obtained through uncertainty quantification. The lower band of the minimum core level is maintained still above the top of the active core section, thus the core uncover will not occur with 95% confidence level. Important input uncertain contributors for the minimum core level are identified through the measure of Spearman rank correlation coefficients in sensitivity analysis. The demonstration of best-estimate plus uncertainty analysis (BEPU) application will provide some guidance for the safety analysis of advanced passive nuclear power plants.

Study on public acceptance of nuclear power plants: Evidence from China

This empirical study evaluated the public acceptance of nuclear-power plants in China. A conceptual framework was proposed to explain the factors affecting nuclear-power acceptance based on antecedent variables, including social-media-use frequency, social-media information trust, nuclear-power knowledge, nuclear-accident knowledge, and risk-and-benefit perception. An empirical study was operated based on the Haiyang nuclear-power plant by conducting a face-to-face survey among residents who use social-media platforms near the plant. The frequency of social-media-use and the trust on social-media information promote individuals’ knowledge about nuclear power and nuclear accidents, leading to risk and benefit perception. Finally, benefit perception results in nuclear-power acceptance among the individuals. Implications and suggestions for future research are discussed.

Characteristics of wind-induced displacement of super-large cooling tower based-on continuous medium model wind tunnel test

A cooling tower is a wind-sensitive structure, and wind loading is used as the control load for its design. In this study, the displacement characteristics of a large concrete cooling tower with respect to a turbulent wind is investigated by using a continuous medium model wind tunnel test. Firstly, based on the similarity relations of the continuous medium model for the cooling tower, which were derived and verified in the present study, a continuous medium model with a geometrical scale of 1:400 is designed and processed for a 200 m high cooling tower at a nuclear power plant in China. Subsequently, wind tunnel tests are carried out to measure the wind-induced displacement using a high-precision laser displacement sensor. Based on the results, the displacement and characteristics of the power spectra of some typical measurement points are analyzed. The analysis result indicates that the continuous medium model can accurately simulate the similarity relations of mass, stiffness, and damping. It is also found that the maximum displacement occurs in the windward side of the throat, and the size is about 20% of the throat thickness. In addition, background response plays a major role in the total displacement response, and the dynamic amplification effect is not obvious. The mean dynamic amplification coefficient is 1.02, which is slightly less than the value of 1.05 specified in VGB-R 610Ue, 2010. At the same time, the test result shows that gust loading factor decreases with increase in height, which is consistent with VGB-R 610Ue, 2010, and the mean value is slightly less than the specified value.

Analysis of Loss of Offsite Power Events at China’s Nuclear Power Plants

The function of the electric power system of nuclear power plants (NPPs) is to provide safe and reliable electricity for the equipment both in normal operation and accident conditions, and to provide emergency power for nuclear safety-related systems to maintain the safety of NPPs. Station blackout (SBO) occurs when loss of offsite power (LOOP) happens concurrently with unavailability of the onsite emergency alternating current (ac) power. LOOP is a precursor of SBO which rarely occurs but contributes significantly to reactor core damage frequency (CDF). Collecting and analyzing all LOOP events in NPPs of China from 1993 to 2017, this paper summarizes the common features of the LOOP events, and identifies the weaknesses and lessons learned from these events. Conclusions and experience feedback suggestions are put forward for improving the reliability of the offsite power supply of NPPs in China.

Environmental impact on the Korean peninsula due to hypothetical accidental scenarios at the Haiyang nuclear power plant in China

Environmental impact on the Korean peninsula due to hypothetical accidental scenarios at the Haiyang nuclear power plant in China

A Review in ITER Project and the Safety Problem of Inland Nuclear Power Plants in China

Under the new situation of China's economic development, the construction of inland nuclear power is of great significance to improve the energy structure, ensure the energy supply and promote the virtuous cycle of economic development and environmental protection. This paper introduces the current situation of nuclear power development at home and abroad and the latest development trend in the field of nuclear power: International Thermonuclear Experimental Reactor (ITER) project. Analysis the structural safety, radiological impact and waste treatment three safety problems of the construction of inland nuclear power in China, and summarizes the current situation and development trend of the technology. Finally, some suggestions are put forward for the construction of future inland nuclear power plants in China.

An Experimental Study on Treatment of Typical Low and Intermediate Level Radioactive Wastes with Thermal Plasma Melting Technology

With the active development of the nuclear industry in China, it is extremely urgent to study and develop advanced technologies for the radioactive waste treatment and disposal. With features of high temperature, high energy density and broad applicability, the thermal plasma melting technology has been considered as one of the key subjects in the radioactive waste treatment research field. A pilot scale experimental study was carried out on the treatment of typical low and intermediate level radioactive wastes (LILWs) from the nuclear power plant in China with thermal plasma melting technology. Two representative wastes, thermal insulation waste and cotton, were selected and melted in the plasma melting furnance at 1250°C for ~ 100 minutes until they were completely vitrified. Meanwhile, tracers of Co2O3, CsCl and SrCO3 were added to the original wastes to simulate the containment effect of 58Co and 60Co, 134Cs and 137Cs as well as 90Sr in the vitrification during the treatment process. The XRD patterns of both vitrification samples displayed as the typical amorphous state. Performances of resultant glass waste-forms, including the physical property, the leachability and the mechanical capacity, were in accordance with the standard requirements of the hign level radioactive waste glass vitrificaton, and were better than those of the cement solidified waste. Further experimental work is in need to better understand the radioactive nuclide migration regularity and to improve the performance of the plasma melting system.

How does trust affect acceptance of a nuclear power plant (NPP): A survey among people living with Qinshan NPP in China.

It is difficult to know whether different dimensions of trust have different effects on local residents’ acceptance of nuclear power plants (NPPs). In previous research such trust has been considered as a single dimensional concept. This paper divides trust into goodwill trust and competence trust, and we explore the ways in which trust affects acceptance of NPPs through structural equation modeling. A survey of 491 people was conducted in Haiyan County, China, where the Qinshan nuclear power plant is located. We find that goodwill trust is significantly correlated with competence trust, and each can indirectly promote residents’ acceptance of NPPs but by different paths. Goodwill trust improves acceptance of NPPs by decreasing risk perception, while competence trust improves acceptance of NPPs by increasing benefit perception. However, the associations between goodwill trust and benefit perception, competence trust and risk perception, are not significant.

Tornado Hazard Assessment for a Nuclear Power Plant in China

Tornado is one of the most hazardous external natural events which should be taken into account in the siting, design and safety evaluation of nuclear power plants. The tornado hazard has been assessed for a nuclear power plant located in the Southeast China in this paper. Using the original Fujita scale and grading by a number of experts, intensities of the tornado segments have been determined. The design-basis tornado wind speed, parameters and missiles generated have been evaluated following the methodology listed in the hChinese Nuclear Safety Guide HAD101/10. The results show that the overall cumulative frequency and intensity of tornadoes in the site area is not in a logarithm-linear relationship. The expected annual tornado occurrence frequencies of various F scales have been estimated by fitting higher intensity samples. The resulting wind speed corresponding to an exceedance frequency of 10-7 per year seems to be sensitive to the fitting samples. Considering the uncertainties, the intensity and frequency of tornadoes in the survey area, the ultimate design-basis tornado wind speed is taken to be 70.4 m/s, which is the lower limit wind speed of F3 scale. Moreover current problems in tornado hazard assessment in China are discussed.

Leveraging intergovernmental and cross-sectoral networks to manage nuclear power plant accidents: A case study from China

Addressing nuclear power plant accidents (NPPAs) overwhelms the capability of single jurisdictional government and spans the boundaries of multiple sectors. NPPAs management requires public sectors affiliating to multiple governments, private and non-profit sectors to interact with each other for sharing responsibilities, capabilities and information. How to leverage network to improve collaboration and coordination among all the involved organizations presents challenges for Chinese public administrators in NPPAs management. From the emergency management practice of the earliest nuclear power plants in China, this research investigates and conceptualizes governance mechanisms and associated interorganizational relationships involving in each jurisdictional governmental level and among multiple levels of governments in this specific field. The inter-governmental and cross-sectoral NPPAs management network is built, visualized and analyzed at the levels of the node, link, subset of the nodes and whole network based on Social Network Analysis, and managerial implications of improving inter-organizational collaboration in this field are discussed. Our research shows that the current NPPAs network in China mainly relies on the resources and capabilities of public sectors, and the private and non-profit sectors should be integrated into the network for providing diversified emergency services. NPPAs management network is a hybrid network in the centralized political-administrative structure of China, and hierarchical, market and network governance mechanism play essential roles together and complement with each other in the multi-organizational environment. This network demonstrates the characteristics of selective integration, and the interorganizational relationships that should be paid more attention to be sustained are identified and emphasized from the network perspectives. Furthermore, the absence of collaborative relationships among the organizations that poses barriers to interorganizational collaboration is also discovered and the improvement approaches are discussed. This research provides guidance for improving collaboration in NPPAs management in China, and contributes to literature on emergency management network and interorganizational collaboration in the centralized political-administrative structure.

Research on Applying Dry Cooling Technology in Conventional Island of AP1000 Nuclear Power Plant in China

Research on Applying Dry Cooling Technology in Conventional Island of AP1000 Nuclear Power Plant in China