scholarly journals Coupling of Modular High-Temperature Gas-Cooled Reactor with Supercritical Rankine Cycle

2008 ◽  
Vol 2008 ◽  
pp. 1-9
Author(s):  
Shutang Zhu ◽  
Ying Tang ◽  
Kun Xiao ◽  
Zuoyi Zhang
Keyword(s):  
High Temperature ◽  
Steam Turbine ◽  
Power Plants ◽  
Rankine Cycle ◽  
Steam Pressure ◽  
Energy Conversion Efficiency ◽  
Module Design ◽  
Reheat Steam ◽  
Main Steam ◽  
High Temperature Gas

This paper presents investigations on the possible combination of modular high-temperature gas-cooled reactor (MHTGR) technology with the supercritical (SC) steam turbine technology and the prospective deployments of the MHTGR SC power plant. Energy conversion efficiency of steam turbine cycle can be improved by increasing the main steam pressure and temperature. Investigations on SC water reactor (SCWR) reveal that the development of SCWR power plants still needs further research and development. The MHTGR SC plant coupling the existing technologies of current MHTGR module design with operation experiences of SC FPP will achieve high cycle efficiency in addition to its inherent safety. The standard once-reheat SC steam turbine cycle and the once-reheat steam cycle with life-steam have been studied and corresponding parameters were computed. Efficiencies of thermodynamic processes of MHTGR SC plants were analyzed, while comparisons were made between an MHTGR SC plant and a designed advanced passive PWR - AP1000. It was shown that the net plant efficiency of an MHTGR SC plant can reach 45% or above, 30% higher than that of AP1000 (35% net efficiency). Furthermore, an MHTGR SC plant has higher environmental competitiveness without emission of greenhouse gases and other pollutants.

Design, Operation and Maintenance of Thermal Hydraulic Instrumentation System of HTR-10

2010 ◽  
Author(s):  
Liqiang Wei ◽  
Shuoping Zhong
Keyword(s):  
High Temperature ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Steam Pressure ◽  
Coolant Temperature ◽  
Primary Loop ◽  
Operation And Maintenance ◽  
Main Steam ◽  
High Temperature Gas

The 10 MW high temperature gas-cooled reactor–test module (HTR-10) reached the first critical at the end of year 2000, and has been running for over 9 years safely and stably till now. Comparing with the Pressure Water Reactor (PWR), HTR-10 has many different characteristics, such as core construction, special fuel elements, helium coolant and so on. Thus the thermal hydraulic parameter measurement has special requirement and it is indispensable to select or develop some new class 1E instrumentation and devices. This paper describes measurement requirements, measurement method and measurement instrumentations for measuring coolant temperature, primary loop pressure, primary loop mass flow rate, primary loop humidity, main steam pressure, feedwater mass flow rate, in-core components temperature, pressure vessel surface temperature. The class 1E sheathed thermocouples and thermocouple penetration assembly, the class 1E orifice plate throttle device, and the data acquisition and supervision system that were developed by the Institute of Nuclear and New Energy Technology (INET) according to the criteria IEEE 323 and IEEE 344 are introduced in detail. HTR-10 has been operated successfully for over 9 years up to the present. The operation and maintenance experience of above-mentioned instrumentations shows they are safe and reliable at normal and abnormal conditions. The experience described in this paper is valuable for the latter 2 × 250 MW modular high temperature gas-cooled reactor.

Analytic Optimization of Cost Effective Thermoelectric Generation on Top of Rankine Cycle

2013 ◽  
Author(s):  
Kazuaki Yazawa ◽  
Yee Rui Koh ◽  
Ali Shakouri
Keyword(s):  
Steam Turbine ◽  
Fuel Efficiency ◽  
Cost Effective ◽  
Rankine Cycle ◽  
Energy Conversion Efficiency ◽  
Design Parameters ◽  
Steam Temperature ◽  
Combined System ◽  
Fuel Consumption Rate ◽  
The Impact

Thermoelectric (TE) generators have a potential advantage of the wide applicable temperature range by a proper selection of materials. In contrast, a steam turbine (ST) as a Rankine cycle thermodynamic generator is limited up to more or less 630 °C for the heat source. Unlike typical waste energy recovery systems, we propose a combined system placing a TE generator on top of a ST Rankine cycle generator. This system produces an additional power from the same energy source comparing to a stand-alone steam turbine system. Fuel efficiency is essential both for the economic efficiency and the ecological friendliness, especially for the global warming concern on the carbon dioxide (CO2) emission. We report our study of the overall performance of the combined system with primarily focusing on the design parameters of thermoelectric generators. The steam temperature connecting two individual generators gives a trade-off in the system design. Too much lower the temperature reduces the ST performance and too much higher the temperature reduces the temperature difference across the TE generator hence reduces the TE performance. Based on the analytic modeling, the optimum steam temperature to be designed is found near at the maximum power design of TE generator. This optimum point changes depending on the hours-of-operation. It is because the energy conversion efficiency directly connects to the fuel consumption rate. As the result, physical upper-limit temperature of steam for ST appeared to provide the best fuel economy. We also investigated the impact of improving the figure-of-merit (ZT) of TE materials. As like generic TE engines, reduction of thermal conductivity is the most influential parameter for improvement. We also discuss the cost-performance. The combined system provides the payback per power output at the initial and also provides the significantly better energy economy [$/KWh].

Repowering and Retrofitting

2002 ◽  
Author(s):  
Andreas Pickard
Keyword(s):  
Steam Turbine ◽  
Power Plants ◽  
Free Market ◽  
Leading Edge ◽  
Project Planning ◽  
Combined Cycle ◽  
Steam Turbines ◽  
Planning Stage ◽  
Reheat Steam ◽  
Plant Optimization

At the start of this new century, environmental regulations and free-market economics are becoming the key drivers for the electricity generating industry. Advances in Gas Turbine (GT) technology, allied with integration and refinement of Heat Recovery Steam Generators (HRSG) and Steam Turbine (ST) plant, have made Combined Cycle installations the most efficient of the new power station types. This potential can also be realized, to equal effect, by adding GT’s and HRSG’s to existing conventional steam power plants in a so-called ‘repowering’ process. This paper presents the economical and environmental considerations of retrofitting the steam turbine within repowering schemes. Changing the thermal cycle parameters of the plant, for example by deletion of the feed heating steambleeds or by modified live and reheat steam conditions to suit the combined cycle process, can result in off-design operation of the existing steam turbine. Retrofitting the steam turbine to match the combined cycle unit can significantly increase the overall cycle efficiency compared to repowering without the ST upgrade. The paper illustrates that repowering, including ST retrofitting, when considered as a whole at the project planning stage, has the potential for greater gain by allowing proper plant optimization. Much of the repowering in the past has been carried out without due regard to the benefits of re-matching the steam turbine. Retrospective ST upgrade of such cases can still give benefit to the plant owner, especially when it is realized that most repowering to date has retained an unmodified steam turbine (that first went into operation some decades before). The old equipment will have suffered deterioration due to aging and the steam path will be to an archaic design of poor efficiency. Retrofitting older generation plant with modern leading-edge steam-path technology has the potential for realizing those substantial advances made over the last 20 to 30 years. Some examples, given in the paper, of successfully retrofitted steam turbines applied in repowered plants will show, by specific solution, the optimization of the economics and benefit to the environment of the converted plant as a whole.

scholarly journals Study on Probabilistic Safety Goals for Multimodule High-Temperature Gas-Cooled Reactor Based on Chinese Societal Risks

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Jinghan Zhang ◽  
Jun Zhao ◽  
Jiejuan Tong
Keyword(s):  
High Temperature ◽  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Regulatory Commission ◽  
Nuclear Safety ◽  
Energy Agency ◽  
Water Reactor ◽  
Regulatory Commission ◽  
High Temperature Gas ◽  
Probabilistic Safety

Nuclear safety goal is the basic standard for limiting the operational risks of nuclear power plants. The statistics of societal risks are the basis for nuclear safety goals. Core damage frequency (CDF) and large early release frequency (LERF) are typical probabilistic safety goals that are used in the regulation of water-cooled reactors currently. In fact, Chinese current probabilistic safety goals refer to the Nuclear Regulatory Commission (NRC) and the International Atomic Energy Agency (IAEA), and they are not based on Chinese societal risks. And the CDF and LERF proposed for water reactor are not suitable for high-temperature gas-cooled reactors (HTGR), because the design of HTGR is very different from that of water reactor. And current nuclear safety goals are established for single reactor rather than unit or site. Therefore, in this paper, the development of the safety goal of NRC was investigated firstly; then, the societal risks in China were investigated in order to establish the correlation between the probabilistic safety goal of multimodule HTGR and Chinese societal risks. In the end, some other matters about multireactor site were discussed in detail.

Thermodynamic Analysis of Power Generation Cycles With High-Temperature Gas-Cooled Nuclear Reactor and Additional Coolant Heating Up to 1600 °C

2018 ◽  
Vol 140 (2) ◽  
Author(s):  
Michał Dudek ◽  
Zygmunt Kolenda ◽  
Marek Jaszczur ◽  
Wojciech Stanek
Keyword(s):  
Energy Efficiency ◽  
High Temperature ◽  
Thermodynamic Analysis ◽  
Power Plants ◽  
Nuclear Reactor ◽  
Electric Energy ◽  
High Energy ◽  
Medium Size ◽  
Outlet Temperature ◽  
High Temperature Gas

Nuclear energy is one of the possibilities ensuring energy security, environmental protection, and high energy efficiency. Among many newest solutions, special attention is paid to the medium size high-temperature gas-cooled reactors (HTGR) with wide possible applications in electric energy production and district heating systems. Actual progress can be observed in the literature and especially in new projects. The maximum outlet temperature of helium as the reactor cooling gas is about 1000 °C which results in the relatively low energy efficiency of the cycle not greater than 40–45% in comparison to 55–60% of modern conventional power plants fueled by natural gas or coal. A significant increase of energy efficiency of HTGR cycles can be achieved with the increase of helium temperature from the nuclear reactor using additional coolant heating even up to 1600 °C in heat exchanger/gas burner located before gas turbine. In this paper, new solution with additional coolant heating is presented. Thermodynamic analysis of the proposed solution with a comparison to the classical HTGR cycle will be presented showing a significant increase of energy efficiency up to about 66%.

An Ericsson Cycle GT Design by LNG Cryogenic Heat Utilization

2000 ◽  
Author(s):  
Kirk Hanawa
Keyword(s):  
High Temperature ◽  
Heat Exchangers ◽  
Power Plants ◽  
Sea Water ◽  
Rankine Cycle ◽  
Exhaust Gas ◽  
Energy Potential ◽  
Thermodynamic Cycles ◽  
Cycle Temperature ◽  
Better Than

In many LNG receiving terminals worldwide, the cryogenic heat of imported LNG which was liquefied by using 10% energy of natural gas supply1), 2), has been wasted into the sea water mainly through heat exchangers like ORVs (Open Rack Vaporizer)3). This cryogenic heat of 110 K (-256 F) class is considered, however, as an excellent energy source to apply thermodynamic cycles. Several literature, accordingly, are found to improve such high-grade energy potential of LNG regasification process as a low temperature sink, combining with fired heater at 1,100 K (1520 F) class or GT main exhaust gas at 700 K (800 F) class as a high temperature source, through Brayton and Rankine cycles5),6),7),8),9). This paper presents a typical example of closed “Ericsson” cycle which has the minimum cycle temperature of 157 K (-176 F) from LNG cryogenic heat and the maximum of 550 K (531 F) from the partial HRSG exit heat mixed with the partial GT exit gas. This closed gas turbine, from viewpoints of minor modification to existing power plants and no energy impacts for high temperature source, which would be better than the above-described idea, is able to offer 35% thermal efficiency. And it is recognized that this system would be superior to existing cryogenic generation systems of 20% class operated by Rankine Cycle.

scholarly journals Using Wireless Sensor Networks to Achieve Intelligent Monitoring for High-Temperature Gas-Cooled Reactor

2017 ◽  
Vol 2017 ◽  
pp. 1-8
Author(s):  
Jianghai Li ◽  
Jia Meng ◽  
Xiaojing Kang ◽  
Zhenhai Long ◽  
Xiaojin Huang
Keyword(s):  
High Temperature ◽  
Nuclear Power ◽  
Power Plants ◽  
Heterogeneous Data ◽  
Wireless Sensor ◽  
Support Vector ◽  
Intelligent Monitoring ◽  
Novel Algorithms ◽  
Non Gaussian ◽  
High Temperature Gas

High-temperature gas-cooled reactors (HTGR) can incorporate wireless sensor network (WSN) technology to improve safety and economic competitiveness. WSN has great potential in monitoring the equipment and processes within nuclear power plants (NPPs). This technology not only reduces the cost of regular monitoring but also enables intelligent monitoring. In intelligent monitoring, large sets of heterogeneous data collected by the WSN can be used to optimize the operation and maintenance of the HTGR. In this paper, WSN-based intelligent monitoring schemes that are specific for applications of HTGR are proposed. Three major concerns regarding wireless technology in HTGR are addressed: wireless devices interference, cybersecurity of wireless networks, and wireless standards selected for wireless platform. To process nonlinear and non-Gaussian data obtained by WSN for fault diagnosis, novel algorithms combining Kernel Entropy Component Analysis (KECA) and support vector machine (SVM) are developed.

Economic Analysis for Nozzle Governing With Overload Valve Regulation Technology

2017 ◽  
Author(s):  
Jing Fangbo ◽  
Lai Qiang ◽  
Wei Dongliang ◽  
Chen Xianhui ◽  
Yuan Yongqiang
Keyword(s):  
Steam Turbine ◽  
Peak Load ◽  
Electricity Consumption ◽  
Control Valve ◽  
Clean Energy ◽  
Steam Pressure ◽  
Bypass Valve ◽  
Partial Load ◽  
Main Steam ◽  
Load Conditions

With the implementation of low-carbon economy policy, clean energy (such as wind and solar energy) has been developing rapidly, and the percentage is increasing year by year; On the other hand, with a steadily growing percentage of residential electricity consumption and commercial electricity consumption, resulting in large electricity load difference between peak and valley, the load related requirements of modern steam power plants are noticeably changing. Whereas the past units being designed in base load now have to take part in peak load, and usually in a low load operation, unable to play its advantages of high efficiency in design load. In the article the current three main governing methods (i.e. nozzle governing, throttling governing and bypass governing) for steam turbine will be discussed and evaluated under economical criteria focused on the above described challenges for future power generating technologies. A new governing method is Nozzle governing with Overload Valve Regulation, which keeps the advantage that main steam pressure of the Nozzle governing steam turbine is higher under partial load conditions, and weakens the influence of the low efficiency of governing stage on high pressure turbine, effectively improves the efficiency of steam turbine unit under partial load conditions. In the turbine adopted the new governing method of Nozzle governing with Overload Valve Regulation, the first stage is governing stage, divided into several groups. Main steam from boiler goes through the main stop valve and main steam control valve in sequence, and then turns to the governing stage. When the load is below 85%THA, main steam control valve I, II and III are fully opened, main steam control valve IV is fully closed, and the unit is in sliding pressure operation. When the load is 85%THA, the main steam pressure can reach the rated pressure. With the load increasing, main steam control valve IV starts to open, but the main steam pressure maintains the rated pressure, adjusted to THA when main steam control valve IV is fully opened and the flowrate of governing stage reaches the maximum. In the load more than THA condition, the bypass valve starts to open, the main steam goes through the bypass steam room into the certain stage (as fourth), to meet the requirements of the super load, adjusted to VWO (about 108%THA) when the bypass valve is fully opened. Through the detailed description about the scheme set and calculation analysis about economy benefit of the new regulation technology of Nozzle governing with Overload Valve Regulation, it shows that with the annual load range of 40%THA–85%THA, the economy of turbine adopted the new regulation technology is better than bypass governing by about 21.6 kJ/kW.h. (CSPE)

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