核动力工程

Limit Loads of Thick-Walled Cylinders with a Fully-Circumferential Crack under Combined Internal Pressure and Axial Tension Based on Slip-Line Field Method

CAI Gang-si, GAO Zeng-liang, LIANG Li-hua, LEI Yue-bao

2007, 28(3): 1-5,37.

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Based on slip-line field method,limit load solutions for thick-walled cylinders without defects and with a fully-circumferential inner crack under combined internal pressure and axial tension are derived,considering the elastic-perfectly-plastic material model.Numerical examples show that the solutions in this paper for the cylinder with inner crack agree well with the results of the elastic perfectly-plastic finite element analysis,and are conservative.For cylinder with inner crack,its limit load solution based on simplified slip-line field is only applicable for the very deep cracks.For other cases,the limit loads based on Mises crite-rion is proposed instead.

Mathematic Model of Molten Material in Neighbor Assembly in Fast Reactor

ZHAO Shu-feng, LUO Rui, SHI Xiao-bo, WANG Zhou, YANG Xian-ong

2007, 28(3): 6-9,42.

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Running under the accident condition,the fuel pins of the LMFBR will melt,which then lead to the molten pool and boiling pool scenarios.When the molten material propagates into the neighbor subas-semblies,the key point is that whether the neighbor subassembly will be total blocked radially.To make the conduction is the prior mechanism;and the conduction freezing model is better than bulk freezing model in the prediction of the structure temperature and the crust growth.penetration mechanism in neighbor subassembly clear,a conduction freezing model and a bulk freezing model are established which are validated on the UK SMPR experiment.The result shows that both conduc-tion freezing and bulk freezing mechanism will be the reason of blocking;and when the pressure is low,the

Freezing Model of Double Constitute Molten Mixture in Fast Reactor Severe Accident

ZHAO Shu-feng, LUO Rui, WANG Zhou, SHI Xiao-bo, YANG Xian-yong

2007, 28(3): 10-13,55.

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Under serious accidental conditions in fast reactors,the fuel pins will be molten which finally lead to formation of molten pool and boiling pool.Later on,the molten material will break the wrapper of the subassembly.In order to understand the penetration mechanism of the molten material,two mechanism mod-els are established to simulate the penetration process: the conduction-freezing model and the bulk-freezing model.And they are validated on the UK SES out-of-pile experiments.In comparison with the single-material freezing model which is validated on GEYSER experiments,the influence of steel on freezing process is ana-lyzed,and finally some conclusions relative to the penetration are derived.

Study on MAs Transmutation of Accelerator-Driven System Sodium-Cooled Fast Reactor Loaded with Metallic Fuel

HAN Song, YANG Yong-wei

2007, 28(3): 14-18,55.

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Through the analysis of the effect of heavy metal actinides on the effective multiplication constant（keff） of the core in accelerator-driven system（ADS） sodium-cooled fast reactor loaded with metallic fuel,we gave the method for determining fuel components.The characteristics of minor actinides（MAs） transmutation was analyzed in detail.3D burn-up code COUPLE,which couples MCNP4c3 and ORIGEN2,was applied to the neutron simulation and burn up calculation.The results of optimized scheme shows that adjusting the proportion of 239Pu and maintaining the value during the burn-up cycle is an efficient method of designing keff and keeping stable during the burn-up cycle.Spallation neutrons lead to the neutron spectrum harder at inner core than that at outer core.It is in favor of improving MA’s fission cross sections and the cap-ture-to-fission ratio.The total MAs transmutation support ratio 8.3 achieves excellent transmutation effect.For higher flux at inner core leads to obvious differences on transmutation efficiency,only disposing MAs at inner core is in favor of decreasing the loading mass and improving MAs transmutation effect.

Influences of Flow Oscillations on Critical Heat Flux

WU Jun-mei, SU Guang-hui

2007, 28(3): 19-21,60.

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An Artificial Neural Network,denoted by ANNosci,has been trained successfully to predict the critical heat flux（CHF） under flow oscillations in this paper.The effects of flow oscillations on nondi-mensionalized factor F is analyzed by using the ANNosci.The analyzed results show that the influence of the system pressure on the nondimensionalized factor F is multivalued due to the effects of other parameters.The nondimensionalized factor F will increase with an increase of mean mass flow rate,in general.The influ-ences of flow oscillation on the critical heat flux are also analyzed.The results show that these effects are very complex.Shortly,CHF decreases with increasing the ratio of oscillation amplitude of mass flow rate to mean mass flow rate.When the ratio of oscillation amplitude of mass flow rate to mean mass flow rate is constant,CHF decreases with increasing the oscillation period.

Study on Flow Characteristics of Isothermal Jet into Cross-Flow for Safety Injection Inclined Tube in the Reactor Cooling System

HE Hui-ning, LUO Yu-shan, WANG Hai-jun, MAO Qing, ZHANG Yi-xiong

2007, 28(3): 22-26.

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In order to investigate the flow characteristics of isothermal jet into cross-flow for a safety characteristics,the effect region and the factors that contribute to the flow characteristics were studied.Based on the results,it can be concluded that the velocity ratio was the most important factor in this flow type.The calculations were agreed well with the visualization tests.injection（SI） inclined tube in the reactor cooling system,the numerical simulations were carried out at vari-ous velocity ratios between jet and main flow by using the commercial computational fluid dynamics software CFX.Via the computations,the 3-D flow traces of the typical operation condition were obtained,also the flow

Numerical Study of Heat Transfer and Fluid Flow in Rectangular Narrow Channel with Periodically Mounted Longitudinal Vortex Generators

WANG Ling, HUANG Jun, WANG Qiu-wang, HUANG Yan-ping

2007, 28(3): 27-31.

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Heat transfer enhancement for convective channel flows is often obtained by some ribs periodically mounted on the heat transfer surface which induces vortices to augment transverse fluid mixing.In this paper,the performance of turbulent flow and heat transfer in a narrow rectangular channel with periodically roughened by rectangular bars as LVGs are studied by numerical simulation for water with Reynolds number ranging from 1.5×10⁴ to 3.5×10⁴,the effect of the height of LVGs,angle of incidence,space between LVGs were also analyzed.It was found that the LVGs are able to greatly improve the comprehensive heat transfer performance.The best effect of heat transfer could been obtained when the incidence angler equals to 50°.

Conjugated Heat Transfer of Natural Convection in Pool with Internal Heat Sources and Convection in the Tube

LI Long-jian, LIU Hong-tao, CUI Wen-zhi

2007, 28(3): 32-37.

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The conjugated heat transfer of natural convection in pool with internal heat source and the forced convection in the tube was analyzed,and the corresponding three-dimensional physical and mathe-matical model was proposed.A control volume based finite element method was employed to solve numeri-cally the problem.The computations were performed for different internal heat source intensity of the pool and the different flow velocity in the tube.The computed heat transfer coefficients on the inner and outer wall showed well consistency of those calculated with the empirical correlations.Compared with the measured total heat transfer coefficients between the fluids in and out of the tube,the computed ones showed also the well consistency,which implied that the numerical model proposed in this paper was reliable.The research results revealed that the total heat transfer coefficients between the fluids were strongly affected by the inter-nal heat source intensity of the pool liquid and the flow velocity in the tube.

Experimental Study on the Heat Transfer of Water Boiling Flow in Narrow Horizontal Rectangular Channels

YANG Xiao-qiang, QIU Sui-zheng, JIA Xiao-hong, YIN Hai-feng, JIA Dou-nan, LU Dong-hua

2007, 28(3): 38-42.

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The characteristics of boiling heat transfer were experimentally investigated in narrow rec-perimental data well.tangular channels with large width-height ratio at pressure ranging from 1.0 to 6.0MPa.The effect of pressure,heat flux,mass flux,gap size and quality on the heat transfer was analyzed.At last,a new developed correla-tion calculated heat transfer coefficients was obtained in narrow rectangular channels,which can predict ex-

Investigation on Heat Transfer Characteristics of Ultra-Supercritical Water in Vertical Upward Internally Ribbed Tube

WANG Wei-shu, LUO Yu-shan, CHEN Ting-kuan, GU Hong-fang, ZHU Xiao-jin, WANG Hai-tao, JI Qing

2007, 28(3): 43-46,60.

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In ultra-supercritical pressure region,the heat transfer characteristics of water in a vertical upward internally ribbed tube with the diameter of Φ28.6×5.8mm have been experimentally investigated.The tests have been performed under various conditions with the pressure ranging from 25 to 35Mpa,the mass velocity from 450 to 1800 kg/（m2.s）,and the internal wall heat flux from 200 to 600 kW/m2.The results show that the heat transfer of ultra-supercritical water is better below the pseudo-critical point than that above the pseudo-critical point.Increasing the mass velocity can improve the heat transfer of ultra-supercritical water with a much stronger effect below the pseudo-critical point than that above the pseudo-critical point.The pressure has only a moderate effect on the heat transfer of ultra-supercritical water when the temperature of water is below the pseudo-critical point.Sharp rising of inner wall temperature near the pseudo-critical region takes place earlier at a higher pressure.For given pressure and mass velocity,the internal wall heat flux also shows a significant effect on the distributing of inner wall temperature.The inner wall temperatures are higher at a higher heat flux.Increasing of internal wall heat flux leads to an early occurrence of sharp rising of the wall temperature.Based on the experiments,correlations of heat transfer coefficients are also presented for the vertical upward internally ribbed tubes.

Analysis of Slug Flow Unit Model in Rolling Vertical Tube

CAO Xia-xin, YAN Chang-qi, SUN Zhong-ning

2007, 28(3): 47-50.

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The slug flow unit model in rolling vertical tube was analyzed in this paper,by setting up some equations,such as mass conversation equations and the necessary conditions for the existence of slug unit model could be used as the basis for further analyzing the flow property of slug flow under rolling con-dition.flow.Based on this slug flow unit model,the correlation for calculating average void fraction of slug flow in rolling tube was presented,and the calculations were agreed well with experimental data.So,this slug flow

Pressure Drop Characteristics of Single-Phase Flow in Vertical Rolling Pipes

CAO Xia-xin, YAN Chang-qi, SUN Li-cheng, SUN Zhong-ning

2007, 28(3): 51-55.

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Experimental studies of single-phase pressure drop in rolling pipes were carried out.The in-side diameters of three pipes which were fixed on the rolling platform were 15mm,25mm,and 34.5mm re-spectively,the rolling periods of the rolling platform could be set as 5s,10s,15s,and rolling angles of the rolling platform were 10° and 20°.The experimental results showed that the frictional factor periodically fluctuated with the time variable,and its amplitude was obviously affected by the change of Reynolds number and pipe diameters.The amplitude and average value of frictional factor both decreased with the increase of Re number,but the bigger the tube diameter was,the larger the amplitude of frictional factor was.At any moment,the transient frictional factor increased with the increase of rolling period.However,the effect of changing rolling angles on the frictional factor was not obvious.

Burn-Up Automatic Measure System of 10MW High Temperature Gas Cooling Reactor

MA Tao, HU Shou-yin, LIANG Xi-hua, HUANG Peng

2007, 28(3): 56-60.

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In order to ensure the high availability of pebble bed type high temperature gas cooling reactor,it is the critical process to measure the burn-up level for each ball in accurate and efficient way.The automatic operation of burn-up measurement of 10MW high temperature reactor（HTR-10） is unimplemented yet.Ac-cording to the design theory of FCA system and operation characters of fuel circulation procedure,the original manual flow of burn-up level measurement methods is improved and burnup can be automatically measured.The field operation results have proved the reliability in performance and the accuracy in logic.It can effec-tively avoid the accidents caused by error operation.

Analyzing and Realizing of Database Function of Fast Reactor Refueling Supervision System

WANG Jin-cheng, LI Ju

2007, 28(3): 61-64.

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Using computers to inspect the nuclear reactor fuel-changed system is helpful for the im-provement of the security and reliability of the refueling operation.Nuclear reactor refueling supervision sys-tem is developed with the configuration software.Because the system is very complex and a great deal of data should be recorded,it requires a powerful database to suport.This paper analyzes the data to be recorded and introduces the solution for real-time recording.

Application of Automatic Liquid Metal Control in Reactors

SHAN Jian-qiang, RAN Xu, YANG Shuai, ZHANG Bin, ZHU Ji-zhou

2007, 28(3): 65-67,102.

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According to the characteristics of space fast reactors,liquid metal lithium is selected as con-trol material.This paper analyzed the reactor startup,burnup compensation,loss of flow and overpower,and verified the feasibility of application of fully automatic liquid metal control in reactors.

Development and Verification of In-Core Fuel Management Code Package for Uranium Zirconium Hydride Power Reactor

WANG Lian-jie, YAO Dong, CHEN Bing-de

2007, 28(3): 68-71,112.

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This paper introduces the in-core fuel management code package for uranium zirconium hy-dride power reactor developed on the basis of the assembly parameter and in-core fuel management calcula-tion methods for LWR.The code package is verified by the experimental data of Xi’an pulsed reactor and the design parameters of international interrelated study.The verification shows that the calculated values of thecode package are in good agreement with the experimental data and the physical design values.This code package can be used for the in-core fuel management for the uranium zirconium hydride power reactor.

Multi-Axial Creep Design Models Based on the Cavity Growth Theory and Its Applications in Engineering

YAO Hua-Tang, XUAN Fu-zhen, WANG Zheng-dong, TU Shan-dong

2007, 28(3): 72-77.

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Multi-axial creep is one of the major reasons for the failures of high temperature components,and it is an important factor to be considered in the engineering design.In this paper,the multi-axial creep design approach based on cavity growth mechanisms is generalized.The basic theory for cavity growth is in-multi-axial creep design of elevated temperature components are pointed out and advices for its further re-search are presented.troduced.Five typical multi-axial creep design models based on cavity growth theory are discussed.Applica-tions of these models in R5,RCC-MR,ASME III and VGB-R 509L are analyzed.Difficulties faced in the

Uncertainty Reasoning of Mode Diagnosis for 0Cr18Ni10Ti Pipe Corrosion Failure

MIAO Zhong-hui, JIAO Zeng-geng, CAI Qi

2007, 28(3): 78-81.

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Based on the summarization of failure cases and experience of 0Cr18Ni10Ti pipe,the features of corrosion failure information to be considered are generated.Uncertainty knowledge presentation methods which combines production and frame are devised,and the method for acquiring weights of features in corrosion failure rules is presented.The uncertainty reasoning method of weighted of failure rules is presented,and an example of calculation in diagnosis reasoning is illuminated.The research is the foundation of intelligent diagnosis of corrosion failure mode.

Effect of Long-Term Aging on Tensile Properties of 17-4PH Stainless Steel

PENG Yan-hua, WANG Jun, ZOU Hong, LI Cong, Li Gui-jiang, SHEN Bao-luo

2007, 28(3): 82-86,89.

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In this paper the effect of long-term aging on static tensile properties of 17-4 precipita-tion-hardening stainless steel was studied,and the fracture morphology and the microstructure evolution was observed mainly by scanning electron microscope（SEM） and transmission electron microscope（TEM）,re-spectively.The results showed that with the age time prolonging,yield strength and tensile strength increased,but contraction of area and elongation was decreased.Smaller ductile dimples on the fracture of the quenched and tempered steel became into lager ductile dimples on the fracture of the long-term aged steel,and there was secondary cracks on the fracture of the long-term aged steel.TEM observation showed that microstruc-ture of the steel subjected to long-term aging took place spinodal decomposition,transforming to Cr-rich α’ phase and Fe-rich α phase,which was principally responsible for strength increasing and ductility decreasing.

Analysis and Evaluation for Little Branch of Daya Bay Nuclear Power Station Based on Vibration Test Result

LIU Wen-jin, MAO Qing, ZENG Zhong-xiu, QIN Yu-xin, ZHANG Yi-xiong, WANG Wei, WU Wan-jun, YANG Kai

2007, 28(3): 87-89.

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During the operation of Daya Bay Nulcear Power Station,some little branches of secondary system were with great vibration and even some of them cracked due to the great vibration that may cause some effect on the safety of the power station.This paper performed analysis and evaluation to the eight sys-tems of Daya Bay Nuclear Power Station based on the vibration test results from the examination of the safety during ten years,and the list of the sensitive piping and suggestion for modification were presented based on the analysis results.

DRNN Based Control for Water Level of Saturated Steam Generator

WANG Ying-min, QU Xiao-long, CUI Zhen-hua

2007, 28(3): 90-93,124.

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The neural network has strong self-learning and self-adapting abilities.Presented in this paper is a diagonal recurrent neural network-based control system that is applied to quick and stable identification and self-adaptive level control of the saturated steam generator.The simulation results demonstrate that the developed control system is with good control performances.

Experimental Research of Separation Efficiency on Steam-Water Separator with Corrugated Plates

LI Jia, HUANG Su-yi, WANG Xiao-mo

2007, 28(3): 94-97,124.

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To increase the separating efficiency of corrugated plate separator and optimize the design,the separation efficiency experiment of cold state in steam-water separator with corrugated plates is carried out in this paper.Experimental data of the separating efficiency and pressure reduction of different types of corru-gated plates are compared,which indicates that the separating efficiency of double hook plate is the biggest.The average droplet diameter is estimated by stokes law and accorded with other researchers’ experimental concludes.The influence on dimensionless coefficients of inlet velocity is analyzed.The experiential relation of separation efficiency benefiting the experiments is obtained.

Study on SBO Accident and Mitigating Capability of Auxiliary Feedwater System for PWR

ZHANG Long-fei, ZHANG Da-fa, WANG Shao-ming

2007, 28(3): 98-102.

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Using the best estimate computer code SCDAP/RELAP5/MOD3.4 and Surry NPP as reference object,a representative three loops PWR severe accident calculation model is established and station blackout（SBO） induced core melt progression and phenomenon is analyzed.Effects are discussed when auxiliary fe-edwater（AFW） operates to mitigate the SBO accident progression 1800s and 3600s after SBO starting.Cal-culation results show that core melt progression and failure time of reactor pressure vessel is greatly delayed,thus the operator has more time available for AC recovery and other mitigation measures to prevent reactor pressure vessel failure.

Calculations and Analysis of Molten Core-Concrete Interaction and Its Mitigation Measures under Severe Accidents

GAO Quan-yuan

2007, 28(3): 103-106.

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This paper describes the major mechanism and model of MEDICS code,introduces the calcu-lation methods of the molten core-concrete interaction under severe accidents with MEDICS code,and gives the calculation results of MCCI under severe accidents and its mitigation measures.The calculation results indicate that the top cooling is an effective mitigation measures to MCCI.It can obviously delay the melt-through time of containment base,and largely reduce the total H2 and non-condensible gases release.

Probabilistic Safety Assessment Model in Consideration of Human Factors Based on Object-Oriented Bayesian Networks

ZHOU Zhong-bao, ZHOU Jing-lun, SUN Quan

2007, 28(3): 107-112.

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Effect of Human factors on system safety is increasingly serious,which is often ignored in traditional probabilistic safety assessment methods however.A new probabilistic safety assessment model based on object-oriented Bayesian networks is proposed in this paper.Human factors are integrated into the existed event sequence diagrams.Then the classes of the object-oriented Bayesian networks are constructed which are converted to latent Bayesian networks for inference.Finally,the inference results are integrated into event sequence diagrams for probabilistic safety assessment.The new method is applied to the accident of loss of coolant in a nuclear power plant.The results show that the model is not only applicable to real-time situation assessment,but also applicable to situation assessment based certain amount of information.The modeling complexity is kept down and the new method is appropriate to large complex systems due to the thoughts of object-oriented.

Development of Computerized Procedures System for Nuclear Power Plants

LIU Fei, ZHANG Zhi-jian, PENG Min-jun

2007, 28(3): 113-116.

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In order to improve the application of operating procedures,an computerized procedures presentation system（CPS） for normal operation is developed on embedded real-time operation system VxWorks using C language.This paper introduces the composing of CPS,and the design of human-machine interface are stressed.The validation of CPS is described with the example of cold startup.The system helps operators to enhance the veracity of operation and the work load of operators will be reduced.

Optimization of Equipment Maintenance for Nuclear Power Plant

ZHANG Bao-feng, XIA Hong

2007, 28(3): 117-120.

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Based on the analysis of the features of equipment maintenance for nuclear power plant,pre-ventive maintenance repair models were established in this paper.At the same time,considering the equip-ment of nuclear power plants,a detailed quantitative study on costs resulted from maintenance and failures was carried out.Finally,the decisions and the corresponding changes of preventive maintenance cycle were discussed with the changes of the failure probability and maintenance costs,and the maintenance cycle change curve was given.

Research and Simulation Implementation Based on Novel Scheduling Algorithm of Grid Resources

LUO Guang-chun, LI Jiong

2007, 28(3): 121-124.

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One of the most important functions of the grid is to share resources between multi-virtual organizations,so the scheduling of the grid resources is the key point.This paper produces a novel scheduling algorithm of the grid resources: the minimal hop algorithm.Firstly,we find the resources in the breadth first search way,at the mean time,hop field is generated,and then,we schedule the resources according to the hop field.It is testified by simulation implement that the minimal hop algorithm does improve the efficiency of the grid resources scheduling greatly.

Disposal of Smooth γ Spectrum on Matlab Process

DUAN Zai-yu, CHEN Jian-hua, ZHANG Gui-xin, GONG Jun-jun

2007, 28(3): 125-127.

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Errors may be caused by the statistical fluctuation in the γ spectrum data acquired from NaI（Tl） glitters detector.In order to mitigate this error,the γ spectrum smooth method is proposed in this paper.The process of spectrum data is realized on Matlab according to the smooth principle and the results are as-sessed in mathematics.The results indicate that the errors of the smoothed spectrum are less than those of the non-smoothed spectrum.

2007 Vol. 28, No. 3