The relationship between the control system of the nuclear power plant(NPP) and the condition monitoring system which provides support for the operator is very close, but in most nuclear power plant design, these two ...
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The relationship between the control system of the nuclear power plant(NPP) and the condition monitoring system which provides support for the operator is very close, but in most nuclear power plant design, these two systems are designed separately, which affects the system compatibility, the utilization efficiency of the system resources, the extendibility of the systems and the real–time nature of the support, and may have some negative impacts on the plant operation. Focusing on this problem, an integrated design concept for the NPP control system and condition monitoring system is proposed in this paper. The overview scheme of the integrated system is given based on the analysis of the functions required. Furthermore, the study for modeling of the integrated control and condition monitoring system using the IDEF(Integration Definition Language) and UCM(Use Case Maps) methods is introduced in this paper.
Recent studies on stress corrosion cracking properties of 321 bend pipe and pipe with weld, 316NG austenitic stainless steel pipe in ocean environment in virtue of slow strain rate tensile stress corrosion crack test ...
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Recent studies on stress corrosion cracking properties of 321 bend pipe and pipe with weld, 316NG austenitic stainless steel pipe in ocean environment in virtue of slow strain rate tensile stress corrosion crack test are performed in different concentration of NaCl solution. Elongation and max tensile stress are selected as parameters to evaluate the SCC susceptibility based on the phenomenon that elongation and max stress fall as samples being exposed to NaCl solution environment, the results show that 316NG has the best stress corrosion crack resistance and 321 bend pipe materials behavior oppositely. In addition, the influence of differing strain rate and concentration of NaCl solution on properties of materials are researched, elongation increases along with tensile strain rate enhancement, mechanical properties are immune to variety of Cl- concentration from 3.5% to 26.5%.
We performed a benchmark test for strong motion simulation methods using numerical methods (finite difference method and finite element method). We considered a four-layered model, a symmetric basin model and a slant ...
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We performed a benchmark test for strong motion simulation methods using numerical methods (finite difference method and finite element method). We considered a four-layered model, a symmetric basin model and a slant basement basin model. All the results calculated by six teams from different institutions generally show good agreement to each other. We found minor differences of phase arrival time between institutions and minute differences between FDM and FEM for some models.
plate fuel assembly is widely used as the research reactor core geometry due to the narrow rectangular channel benefit, but the research on the post-CHF thermal-hydraulic characteristics in the narrow rectangular chan...
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plate fuel assembly is widely used as the research reactor core geometry due to the narrow rectangular channel benefit, but the research on the post-CHF thermal-hydraulic characteristics in the narrow rectangular channel is few. Once the loss of coolant accident (LOCA) happens the post-CHF thermal-hydraulic characteristics is important for the accident mitigation. This paper studies the characteristics of the inverted annular flow regime during the narrow channel through the comparison between narrow and general channel inside tube heat reflooding experiment, give the assumptions of the post-CHF reflooding flow regime. Then through the comparison of narrow annular channel experimental wall temperature with the RELAP5 simulation wall temperature for this experiment process. The far downstream of the quench front heat flux is obviously lower than the calculated value, so the wall temperature is higher than the calculated wall temperature. The quality is assumed lower during the far downstream of the quench front in the narrow channel experiment. Because the liquid is consumed during the close downstream of the quench front. Through the comparison of the wall temperature between the calculated by code and experimental value, the liquid core in the inverted annular flow regime which may appears during close downstream of the quench front shortly will breakup earlier due to the more severe surrounding steam disturbing, bringing on the quickly consumption of the liquid, then the quality during far downstream of the quench front is higher than general channel.
Direct numerical simulation is a powerful research tool, which provides a level of information and accuracy that cannot be equaled with other approaches. In this paper, the development of a CFD code for direct numeric...
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Direct numerical simulation is a powerful research tool, which provides a level of information and accuracy that cannot be equaled with other approaches. In this paper, the development of a CFD code for direct numerical simulation is described, which is named dnsPisoFoam. In order to validate the code, direct numerical simulation of channel flow with dnsPisoFoam was performed. The present results are compared with existing simulation results and shows good agreement.
During an overpower transient, the fuel rod cladding may be subjected to major stresses due to differential expansion of the fuel and the cladding. This may lead to clad failure through the Pellet Clad Interaction (PC...
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During an overpower transient, the fuel rod cladding may be subjected to major stresses due to differential expansion of the fuel and the cladding. This may lead to clad failure through the Pellet Clad Interaction (PCI) phenomenon. So the aim of this paper is to present the linear power reached during the most limiting condition II transients(Excessive Load Increase (ELI), Uncontrolled RCCA Withdrawal at Power (URWP) and undetected Rod Drop (RD)) with respect to Qinshan-II long cycle fuel management project PCI analysis.
Hydrogen combustion in the containment building may be a threat to containment *** in some subcompartments,hydrogen detonation is more easier to happen,which may destroy the containment structure or the safety equipme...
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Hydrogen combustion in the containment building may be a threat to containment *** in some subcompartments,hydrogen detonation is more easier to happen,which may destroy the containment structure or the safety equipments in the containment. A study has been carried out using the GASFLOW three-dimensional CFD code to evaluate the hydrogen distribution in the subcompartment during a severe *** Chinese 600MW NPP containment is modeling by GASFLOW. The GASFLOW calculation gave detailed results for the spatial distribution of gas concentrations in the reactor coolant pump（RCP） compartment and the steam generator（SG） compartment within containment.
The advanced pressurized water reactor with a tight hexagonal lattice has its potential to improve uranium utilization. With a smaller pitch-to-diameter ratio(p/d) ranging from 1.06 to 1.20, a major problem is the eme...
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The advanced pressurized water reactor with a tight hexagonal lattice has its potential to improve uranium utilization. With a smaller pitch-to-diameter ratio(p/d) ranging from 1.06 to 1.20, a major problem is the emergency core cooling in a loss-of-coolant accident. The NEPTUN-III and FLORESTAN flooding experiments at PSI and KfK have been performed during the verification period 1985-1990, and the results shows that the reflooding behavior of LWHCR is quite different from that of LWR with higher peak clad temperatures and smaller quench rates. The existing system codes like RELAP5, CATHARE, TRAC may not be able to be used in the calculations of the reflooding phase of LWHCR. Though some efforts have been put into the validation of the improvement of codes, the results are not so good. In this study, the characteristics of the reflooding behavior of tight lattice are pointed out, and the deficiencies of the reflooding models of RELAP5/MOD3 are also fount out after a simulation of the NEPTUN-III reflooding test. The precursory cooling in tight lattice is not effective especially at low reflooding rates (<4cm/s), the droplet enhancement is not significant compared to LWR, and the vapor Reynolds number is much smaller. Finally, a few modifications to RELAP5/MOD3 are made. Compared with the original code, the modified one can better predict the reflooding phase of tight lattice especially the peak clad temperatures at low reflooding rates. More work should be done to deal with the heat transfer characteristics in the transition region of reflooding in tight lattice..
作者：
LI Feng-yu李凤宇LU Gu-bing陆古兵CHEN Zhi陈智College of Naval Architecture&Power
Naval University of Engineering Wuhan 430033 China 海军工程大学 船舶与动力学院湖北 武汉 430033 Science and Technology on Reactor System Design Technology LaboratoryNuclear Power Institute of China Chendu 610041 China 中国核动力研究设计院核反应堆系统设计技术重点实验室四川成都 610041
In this paper, nonlinear dynamic response under loss of coolant accident (LOCA) transient in the nuclear reactor coolant system (RCS) is investigated with ANSYS program. Many nonlinear factors, such as different struc...
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In this paper, nonlinear dynamic response under loss of coolant accident (LOCA) transient in the nuclear reactor coolant system (RCS) is investigated with ANSYS program. Many nonlinear factors, such as different structural stiffness in tension and compression, gap and plastic strain caused by main pipes' break etc. are considered. The Secondary development of ANSYS is performed to form the customized module for implementing effective parameterized and modular modeling and LOCA nonlinear analysis. Comparison of the results calculated by ANSYS and program-specific shows that the results are generally consistent, but there are some differences locally. According to the experience of transient dynamic analysis, and there are so many non-linear factors in the reactor coolant system, the difference is acceptable. The efficiency of this engineering analysis is improved remarkably with the convenience of input and modeling, viewable layout and automatic creating of reports, when using the customized module based on ANSYS.
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