核动力工程

Application of Monte Carlo Method in Modified Spatial Effects Factor Calculation in Rod-Insertion Method

ZHAO Zhu-min, CHEN Wei, MOU Zheng-qiang, WANG Ying-lin

2005, 26(6): 531-534.

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The MC method to modify spatial effects in rod-insertion is studied in this paper. With MCNP/4B code, Neutron flux at detector position in Pulsed Reactor has been calculated when the rods were at the top and the bottom position. The spatial factors at the detector have been calculated. A Modified spatil effects method depended on MC calculation was designed. Using this method, all control rods integral worth have been measured in Pulsed Reactor, and the satisfied results are obtained.

Feasibility Study on Application of MOX Fuel in a CANDU Reactor

WANG Xiao-xia, XIE Zhong-sheng

2005, 26(6): 535-538,543.

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The time-average and instantaneous calculations of CANFLEX bundle with MOX fuel in a CANDU reactor are performed, and computational results demonstrate that the maximum bundle power and channel power are under the permissible limits. The transition from natural uranium core to MOX loading core is feasible without major modification of core structure and operation mode. An advanced PWR/CANDU synergism fuel cycle using MOX fuel are proposed and studied. It is estimated that the implementation of advanced PWR/CANDU synergism fuel cycle for Qinshan Phase Ⅲ NPP will increase the burnup to 13900MW·d/t（U）, save Natural Uranium resource 181t/a, and decrease the spent fuel to be disposed～128t/a in comparison with separate PWR and CANDU fuel cycle.

Application of Genetic Algorithm in CANDU Reactor In-core Fuel Management

HUO Xiao-dong, XIE Zhong-sheng

2005, 26(6): 539-543.

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A strategy, using genetic algorithm （GA） to optimize and select the CANDU reactor refueling channels, is proposed in this paper. A back-propagation artificial neural network （BPANN） is incorporated to predict the core parameters, and the evaluation of the predicted results is taken as the fitness of the GA. GAREFUEL, a refueling channel selection code based on the GA and BPANN, is developed. The refueling simulation is performed using the GAREFUEL and FMPHWR for 360 days. The numerical results show that the selected refueling channels can meet the core parameter limits and GAREFUEL has superior efficiency and speed in selecting the refueling channels.

Study of Estimating Method for Residual Radioactive on Decommissioning Nuclear Establishment

XING Hong-chuan, ZHOU Rong-sheng, XU Ji-yun

2005, 26(6): 544-547,571.

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The source term investigation is one of the important processes during decommissioning. This paper presents a general method of estimating the residual radioactivity doses of components or structures in nuclear reactors based on the radiation doses data. Taking the measured radiation dose of control rods as an example, the residual radioactivity dose is calculated. The limits regarding the method and some issues were discussed also.

Transient Characteristic Research on Passive Residual Heat Removal System of Chinese Advanced PWR

XIAO Ze-jun, ZHUO Wen-bin, CHEN Bing-de, JIA Dou-nan

2005, 26(6): 548-553.

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It is for the first time that the transient characteristic test on PRHRS has been performed for Chinese advanced PWR. A total of 78 sets of test data at transient state have been obtained, and the transition characteristics of cold startup, warm startup, startup without the emergency feedwater, water hammer, and pressure peak value were investigated. Subcooled water of EFWT and the air-cooler can slow down the pressure rise effectively while blackout accident occurs. There is no remarkable difference on transition characteristics between cold start-up and warm startup. The main influence factors, for example, feedwater velocity, feedwater temperature, feedwater position, and various position of air cooler on the water hammer were identified, but if feedwater temperature is higher than 52℃ or the resistance of feed water loop is large enough, no water hammer is observed. Transient characteristic research shows that the cold startup and warm startup of the PRHRS have better transition characteristics, and have the capability of removing the core decay residual heat safely.

Characteristics of Single-Phase Natural Circulation under Rolling

TAN Si-chao, ZHANG Hong-yan, PANG Feng-ge, GAO Pu-zhen

2005, 26(6): 554-558.

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In the view of the characteristics of the single-phase natural circulation flow under rolling motion, the research was conducted experimentally. The result showed that the fluid fluctuated under rolling motion, and the frequency of the fluctuation was the same as the rolling frequency. The theoretical analysis showed that the rolling influenced the natural circulation in two aspects, i.e., on one hand rolling motion changed the system position and then changed the natural circulation thermal driven head; on the other hand the additional acceleration by the rolling imposed an additional pressure drop on the fluid. A model of the ingle phase natural circulation flow under rolling condition was constructed. The effects of rolling perid, rolling amplitude and other parameters upon the natural circulation were analyzed and the influence rules were obtained.

Experimental Study on Density-Wave Instability of High Pressure Steam-Water Two-Phase Flow in U-Type Tube

BI Qin-cheng, LIU Wei-min, GAO Feng, WANG Wei-shu, CHEN Ting-kuan

2005, 26(6): 559-562.

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Experiments on the density wave instability of the high pressure steam water two-phase flow in a U-type tube have been performed within the range of pressure from 4 to 10MPa, mass flux from 450 to 1200 kg/m²·s, inlet subcooling from 10 to 70℃, and heat flux from 0 to 650 kW/m². The outer diameter of the U-type tube is 20mm, and the wall thickness is 2mm. The effects of pressure, mass flux, inlet subcooling, and heat flux on the density wave instability were studied and discussed. The experimental results showed that the boiling flow system was more stable as the pressure increased. Heat flux threshold increased with an increase in mass velocity, but steam quality threshold decreased. When inlet subcooling reduced, heat flux threshold decreased. Based on the experimental results and dimensionless analysis, an empirical correlation to predict heat flux threshold was presented. The errors between the predicted threshold and the experimental data lied in a range of 15%

Experimental Study on Pressure Drop of Flow Boiling in the Vertical Narrow Annuli

PENG Chang-hong, GUO Yun, JIA Dou-nan, QIU Sui-zheng, SU Guang-hui, NIE Chang-hua

2005, 26(6): 563-566.

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Experimental study associated with two-phase flow of boiling in the vertical narrow annuli with the gap width of 1.0 and 1.5mm has been conducted. The test section can be simultaneously heated from inner and outer tubes by electricity. The system pressure range examined is from 1.5 to 6.0 MPa. Based on the experimental data, a new correlation of two-phase multiplier, which is based on single liquid phase flow in the ducts, has been developed. The new correlation can predict the experimental data well and the mean deviation is 11.6%

Study on Void Fraction in Rectangle Narrow Chamber

WANG Hai-jun, BI Qin-cheng, WAN Lian-li, CHEN Ting-kuan, LI Hui-xiong, FENG Quan-ke

2005, 26(6): 567-571.

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An experimental study on the void fraction in the rectangle narrow chamber is conducted and Freon-113 is used as the work fluid. The variety rule and computation method of void fraction along the height under different pressures and heating powers have been obtained. The results show that when the volume evaporation quantity is constant, the average void fraction increases with the increasing of pressure, an when the heating power is constant, it will decrease with the increasing of pressure. So at the same thermal load, the average void fraction can be reduced by increasing the working pressure properly.

Experimental Study of Gas-Liquid Flow Pattern in Inclined Pipe

CAO Xia-xin, YAN Chang-qi

2005, 26(6): 572-575.

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A series of co-current gas-liquid flow pattern experiments with two inclination angles were conducted in a 15mm diameter, 6m long acrylic pipe installed on an inclinable trestle. Flow patterns determination and classification were based on the visual observations and the characteristics of pressure differen tial fluctuation, and according to the experimental data, flow pattern maps with different inclination angle were drawn. In addition, through the comparison with the flow pattern map in the same diameter horizontal pipe and the range of flow pattern with different inclination angle, it was found that the inclination angle had a prominent effect on the flow pattern region.

Study on Hydrogen Barrier of Cr-C Alloy Fabricated by Electroplating upon Zirconium Hydride

ZHAO Ping, KONG Xiang-gong, ZOU Cong-pei

2005, 26(6): 576-578,613.

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A chromium-carbon alloy film on a surface of zirconium hydride sample was fabricated by electroplating, and zirconium hydride sample with Cr-C alloy fihn was heated at 700℃ for 144 hours. The test results for microstructure of zirconium hydride with XRD indicated that zirconium hydride had the same microstructure of ZrH_1.801 as what it had before electroplating and heating. It means that the film could be a hydrogen permeation barrier on the zirconium hydride. The composition and microstructure of film were analyzed with XPS and SEM. The results showed that the film was formed with Cr and C, and some O-H chemical bonding exist in the film and some C-H chemical bonding are able to exist in the film. It is believed that the existence of the two chemical bonding is the origin for the formation of hydrogen permeation barrier.

Experiment of Physical Short Fatigue Crack Propagation of 1Cr18Ni9Ti Weld Metal

ZHAO Yong-xiang, YANG Bing, GAO Qing

2005, 26(6): 579-584.

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An experimental research is made on the involving physical short fatigue crack propagation of 1Cr18Ni9Ti pipe-weld metal with a replicating technique. Based on the "effective short fatigue crack criterion"（Fatigue Fract. Eng. Mater. Struct., 1999, 22（6）: 459-468）, the result revealed that the propagation of dominant effective short fatigue crack （DESFC） and the propagation of effective short fatigue cracks （ESFCs）, and their coalescence between ESFCs and DESFC contribute directly to the fatigue damage of material. The non-ESFCs in a form of the densities of ESFCs located ahead of the two tips of the DESFC contribute indirectly to the fatigue damage. In this physical short crack （PSC） regime, it exhibits a weakening micro-structural affecting with respect to a decrease of the densities of ESFCs, and thus the DESFC acts gradually as a long crack. Correspondingly, an agreement of involving statistical behaviour between the densities of ESFCs and the DESFC growth rates is observed. Thus, it is indicated that the difference of the involving micro-structural conditions for the DESFC initiation and growth between the sampling specimens is the intrinsic cause of the involving random fatigue properties. And the fatigue damage process is gradually from a initial chaotic state, to an independent random state at the transition of the micro-structural short crack regime and PSC, and then, to a historic dependent random state in PSC regime of fatigue damage.

Equation of Short Fatigue Crack Growth Law of 1Cr18Ni9Ti Weld Metal

ZHAO Yong-xiang, YANG Bing, GAO Qing

2005, 26(6): 585-592.

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The method is investigated for characterizing the short fatigue crack （SFC） behaviour of 1Cr18Ni9Ti weld metal by the "effective short fatigue crack criterion" （Fatigue Fract. Eng. Mater. Struct., 1999, 22: 459-468）. Three considerations are given. Firstly, the dominant effective short fatigue crack （DESFC） behaviour is a result of the interaction and evolution of the collective SFCs and, therefore, it is deemed suitable to describe their collective behaviour. Secondly, the significant character of microstructural short crack （MSC） regime and physical short crack （PSC） regime for the behaviour of SFCs indicates that it should be well exhibited in the characterization. Thirdly, the stronger irregular behaviour of SFCs indicates the single parameter of cyclic stress or strain amplitude for representing driving force of DESFC growth may be not appropriated. A new growth law for the collective SFCs is derived from a consideration of the local cyclic strain energy density driving the DESFC initiation in the initial zone and, then, driving the DESFC growth in the zones around its tips. The final form of this law is relative to the total cyclic strain energysity of remote fields, which circle the initial zone and, then, the zones around the DESFC tips. Availability has been indicated by an analysis of the test data of present material.

Experimental Study on Evolution of Kinematic Hardening for Stainless Steel 304 under Uni-axial Strain Ratcheting Deformation

YANG Xian-jie, LIN Song, GAO Qing, CAI Li-xun, LIU Yu-jie

2005, 26(6): 593-599.

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The tests of cyclic strain ratcheting and low cycle fatigue for stainless steel 304 underuni-axially cyclic strain at room temperature were conducted to systematically investigate the hardening behavior of the material. The evolutions of elastic field size and back stress were investigated under symmetrical cyclic strain with different strain amplitudes and under the strain ratcheting cycling with combined different engineering strain amplitudes with the specific cyclic ratcheting strain increments. The dependence of the evolutions of isotropic and kinematic hardening on the loading history was observed.

Online Monitoring System of Active Magnetic Bearings for HTR-10GT

PENG Hong, SHI Lei, CHA Mei-sheng, YU Su-yuan

2005, 26(6): 600-604.

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Based on virtual instruments （Ⅵ） technology, we have successfully carded out the real-time monitoring of the operation status of the AMB system, and then made some online and offline data analyses on the status signal to draw out the characteristics of the system operation status to judge whether the system behaves normally or not. The test shows that this preliminary monitoring system is a powerful signal monitoring and analyzing platform which has integrated function and good expansibility in the experiment of a small flexible rotor AMB test rig （AMB-P）’s passing the first BCS.

The Analysis of Density Lock Used in Nuclear Reactor Passive Safety

LU Xiang-bo, YAN Chang-qi, SUN Li-cheng

2005, 26(6): 605-608.

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The action, work principle and characteristics of density locks used in nuclear reactor passive safety are analyzed theoretically. Based on the motion equation and flow circulation in the system, the flow analysis to reactor coolant system with density locks is given; the action and characteristics of density locks are explained.

Application of Active Magnetic Bearing for Rotor System Identification in the HTR-10MW

GU Hui-dong, ZHAO Lei, ZHAO Hong-bin

2005, 26(6): 609-613.

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Because active magnetic bearing could support and inspire the rotor with contactless electromagnetic force, some data in the frequency domain are acquired when the inspired sinusoid sweeping frequency signals are input into the rig, which is an experiment model of the helium turbine rotor in the high temperature, air-cooled reactor （HTR）. With the method of modal analysis, the transfer function and modal shapes are drawn. These results not only could verify the theoretic: analysis result, but also could be provided for the controller design and system failure diagnosis.

Analysis and Evaluation of Seismic Response of Reactor Building for Daya Bay Nuclear Power Plant

LI Zhong-cheng, LI Zhong-xian

2005, 26(6): 614-617,644.

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Daya Bay NPP has been operating safely and stably over 10 years since 1994, and its’seismic analysis of nuclear island was in accordance with the approaches in RCC-G standard for the model M310, in which the Simplified Impedance Matrix Method （SIMM） was employed for the consideration of SSI. Thanks to the rapid progress being made in upgrading the evaluation technology and the capability of data processing systems, methods and software tools for the SSI analysis have experienced significant development all over the world. Focused on the model of reactor building of the Daya Bay NPP, in this paper the more sophisticated 3D half-space continuum impedance method based on the Green functions is used to analyze the functions of the soil, and then the seismic responses of the coupled SSI system are calculated and compared with the corresponding design values. It demonstrates that the design method provides a set of conservatively safe results. The conclusions from the study is hopefully to provide some important references to the assessment of seismic safety margin for the operating NPPs.

Pressure Load from Hydrogen Combustion

SONG Chun-jing, WENG Ming-hui, WANG Yong

2005, 26(6): 618-621.

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As stated in 10CFR § 50.34（f）, containment integrity will be maintained during an accident that releases hydrogen generated from 100％ fuel clad metal-water reaction accompanied by hydrogen burning. This paper presents the method to calculate the combustion pressure load post accidents assuming the combustion process is adiabatic, complete and at constant volume, based on the energy balance equation and ideal gas equation before and after hydrogen Combustion. Then, based on this method, this paper calculates the pressure loads of 300MWe and 1000MWe Nuclear Power Plants designed in China from hydrogen combustion generated 100％ fuel clad metal-water reaction, and demonstrates the containment design of these two types meet the requirements of 10CFR § 50.34（f）.

Safety Surveillance of Activities on Nuclear Pressure Components in China

LI Gan-jie, LI Tian-shu, YAN Tian-wen

2005, 26(6): 622-626.

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The nuclear pressure components, which perform the nuclear safety functions, are one of the key physical barriers for nuclear safety. For the national strategy on further development of nuclear power and localization of nuclear pressure components, there still exist some problems in preparedness on the localization. As for the technical basis, what can not be overlooked is the management. Aiming at the current problems, National Nuclear Safety Administration（NNSA） has taken measures to strengthen the propagation and popularization of nuclear safety culture, adjust the review and approval policies for nuclear pressure components qualification license, establish more stringent management requirements, and enhance the surveillance of activities on nuclear pressure equipment. Meanwhile, NNSA has improved the internal management and the regulation efficiency on nuclear pressure components. At the same time, with the development and implementation of "Rules on the Safety Regulation for Nuclear Safety Important Components" to be promulgated by the State Council of China, NNSA will complete and improve the regulation on nuclear pressure components and other nuclear equipments.

Comparison of Human Reliability Analysis Methods

HE Xu-hong, GAO Jia, HUANG Xiang-rui

2005, 26(6): 627-630.

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The paper presents the comparison criteria and results of 7 selected human reliability analysis methods including THERP, ASEP HRA, HCR, HEART, SLIM, CREAM, and ATHEANA. 12 comparison criteria are advanced and used in this comparison. The comparison criteria and results are based on the information derived from method foundations, model, analysis procedures, application history as well as literature reviews and expert judgment.

Application of ATHEANA in Human Failure Events Analysis

HE Xu-hong, WANG Yao, HUANG Xiang-rui

2005, 26(6): 631-634.

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This paper describes the application of a second-generation human reliability analysis method, a technique for human error analysis （ATHEANA）, in the analysis of the human failure events of TMI-2 accident. The results show the usefulness and effectiveness of ATHEANA in the analysis of the cognitive errors Its future applications and shortcomings are discussed in the end.

Simulation System for Xi’an Pulsed Reactor

YUAN Jian-xin, MOU Zheng-qiang, WANG Ying-lin, ZHAO Xiang-feng

2005, 26(6): 635-639.

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The development, configuration, principle, function and design of software and model of simulation system for Xi’an Pulsed Reactor are described. The simulation systme covers various conditions, such as four operation modes, two core configurations, and normal or abnormal status of nuclear reactor. It can show the phenomena of xenon poisoning of the core. Many other serious accidents and unsafe events are also presented. The simulation system is successfully used for the training of operator and students majoring in nuclear engineering.

Study on Standardization of Nuclear Power Plant 3D Design

XIE Min, WANG Bai-zhong

2005, 26(6): 640-644.

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This paper studied various factors to considered in the development of 3D design standards, established the development principle, and explored the structure of the standard system and the development procedure for the 3D design standard system. The main purpose of the nuclear power plant 3D design standardization is to improve the re-application of the design achievement, promote the design communication and facilitate the accumulation of design experiences.

Evaluation System for Operation on Simulator

DONG Xiu-chen, ZU Jin-hua

2005, 26(6): 645-647.

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The establishment of rational evalutation criteria and method is very important for the evaluation of the operator’s performance on the simulator. Based on the fuzzy mathematics and theory of system analysis, this paper established the evaluation standard, simulating and evaluation methodsfor the operation on the simulator.

Index

2005, 26(6): 648-658.

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2005 Vol. 26, No. 6