核动力工程

Study on In-Core Physical Design Limit Zone for Lead Bismuth Eutectic Cooled Long-life Cycle Reactor

LIU Xiao-li, XIAN Chun-yu

2008, 29(4): 1-4,23.

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Reactivity variation versus core burnup is a key parameter in neutron design for long-life cycle reactor. The factors affecting reactor core loading pattern are studied from neutronic design point of view, based on the core composed of U-Pu-Zr fuel and lead bismuth eutectic coolant. The methodology for defining in-core physical design limiting zone is given, and by analyzing the effects of key parameters such as initial plutonium content and fuel rod pitch-diameter ratio, the in-core physical design limit zone is defined.Analysis results show that the methodology is appropriate and the limiting area defined in this study satisfies the core depletion and core reactivity control requirement.

Angular Multigrid Acceleration Method and Lyusternik-Wagner Extrapolation Acceleration Technique for Two-Dimensional Neutron Transport Equation

WU Hong-chun, SUN Xing-guang, CAO Liang-zhi, SHEN Zhi-jun

2008, 29(4): 5-9,30.

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To improve the efficiency of neutron transport computation, the angular multigrid （ANMG） acceleration method and the Lyusternik-Wagner extrapolation acceleration technique are utilized to accelerate the source iteration process. They are successfully applied to the LESFES code, which is developed to solve the neutron transport equation by the least-squares finite-element method. The numerical results demonstrate that the ANMG acceleration method can save much computation time not only for isotropic scattering problems but also for the highly anisotropic scattering problems. Furthermore, when the Lyusternik-Wagner extrapolation acceleration technique is applied to the ANMG acceleration method, the acceleration effect can be significantly improved.

Processing Methods for Temperature-Dependent MCNP Libaries

LI Song-yang, WANG Kan, YU Gang-lin

2008, 29(4): 10-13,30.

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In this paper,the processing method of NJOY which transfers ENDF files to ACE（A Com-pact ENDF） files（point-wise cross-Section file used for MCNP program） is discussed.Temperatures that cover the range for reactor design and operation are considered.Three benchmarks are used for testing the method: Jezebel Benchmark,28cm-thick Slab Core Benchmark and LWR Benchmark with Burnable Absorbers.The calculation results showed the precision of the neutron cross-section library and verified the correct processing methods in usage of NJOY.

Application of Monte Carlo Methods to Neutron Space-Time Kinetics

SHEN Hua-yun, WANG Kan, GONG Zhao-hu

2008, 29(4): 14-18.

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The paper proposes a method of direct simulation, which is based on Monte Carlo methods, for solving the neutron space-time kinetics problems. By directly simulating the behavior of neutrons and precursors of delayed neutrons, results are obtained. Eliminating various approximate approaches that are always necessary for other methods, this method is universal. To check its validation, relevant program has been developed with appropriate approximations, and has been used to calculate the test problems. The calculation results show it is practical to deal with the kinetics problem by the direct simulation approach.

Spherical Harmonics Method for Neutron Transport Equation in Two-Dimensional Cylindrical （R-Z） Geometry

YE Qing, WU Hong-chun

2008, 29(4): 19-23.

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The spherical harmonics （P_N） method is applied to a second order Self-Adjoint Angular Flux （SAAF） neutron transport equation in the two-dimensional cylindrical coordinates. The spherical harmonics functions are used to expand the angular flux. A set of differential equations about the spatial variables is derived. The spatial variables are discretized by means of the finite element method. A computational code for multi-group neutron transport equation named TEPFEM-C is developed based on the present model. The numerical results of some benchmark problems demonstrate that this method can give high precision results and avoid the ray effect very well.

Transmission Probability Method based on Triangular-z Mesh

LIU Guo-ming, WU Hong-chun

2008, 29(4): 24-30.

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This paper presents a transmission probability method（TPM） to solve the neutron transport equation in three-dimensional triangularz geometry.The source within the mesh is assumed to be spatially uniform and isotropic.At the mesh surface,the constant and the simplified P1 approximation are invoked for the anisotropic angular flux distribution.Based on this model,a code TPMTDT is encoded.It was verified by three 3D Takeda benchmark problems.The results of the present method agree well with those of Monte-Carlo calculation method and Spherical Harmonics method.

Analytical Method of Double-Faced Heat Transfer with Helix Inner Tube

ZHAO Fu-yu, WANG Yao-shuai, PENG Jing-feng

2008, 29(4): 31-34,92.

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An analytical method is proposed to solute the steady characteristics of some special heat exchanging component.This paper discussed the double-faced heat transfer characteristic with helix inner tube,and puts up the energy equation of such heat exchanging component.After solving the equations with analytical method,an analytical expression is given,which can describe the liquid temperature distribution in the component.The method is used for solving two example.In the steam generator calculation,an iterative technique is used for calculating the length of apiece section.

Rolling Effects on Two-Phase Flow Pattern and Void Fraction

YAN Chang-qi, YU Kai-qiu, LUAN Feng, CAO Xia-xin

2008, 29(4): 35-38,49.

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The experimental and theoretical study was carried out for the upward gas-liquid two-phase explained reasonably through the analysis of slip ratio of two-phase flow and theoretical analysis using momentum equation of two-phase flow separating model.

Method for Confirming Flow Pattern of Gas-Water Flow in Horizontal Tubes under Rolling State

LUAN Feng, YAN Chang-qi

2008, 29(4): 39-43.

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An experimental study on the flow patterns of gas-water flow was carried out in horizontal tubes under rolling state. It was found that the pressure drop of two phase flow was with an obvious periodical characteristic. The flow pattern of the gas-water flow was distinguished according to the characteristics of the pressure drop in this paper. It was proved that the characteristics of the pressure drop can distinguish the flow pattern of gas-water flow correctly through comparing with the result of careful observation and high speed digital camera.

Experimental Study on Single-Phase Liquid Friction Factor in Rolling Horizontal Pipe

ZHANG Jin-hong, YAN Chang-qi, CAO Xia-xin, SUN Zhong-ning

2008, 29(4): 44-49.

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Friction pressure drop of single-phase liquid in rolling tube with inner diameter 34.5mm was investigated to develop a general correction of friction factor.The test section was horizontally settled on the rolling platform,which was driven by link gearing and rotated around a set axis.Friction factor is obtained by applying for the energy equation and the Darcy formula.Comparing the experimental results between the rolling and stable state,it is found that the frictional pressure drop depended on not only the flow velocity,tube diameter,but also the rolling period,rolling angle and etc.It is also found that the rolling friction factor displayed the periodic change.By defining rolling Reynolds number and applying dimensional analysis,a new correction of single-phase friction factor is provided incorporating the effects of rolling parameters.The proposed correction can well predict the experimental data.

Numerical Analysis of Thermal-Hydraulic Behavior of Supercritical Water in Square Sub-Channels

GU Han-yang, YANG Yan-hua, CHENG Xu

2008, 29(4): 50-56.

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Research activities are ongoing worldwide to develop nuclear power plants with a supercritical water cooled reactor （SCWR）. However, there is still a big deficiency in understanding and prediction of heat transfer in supercritical fluids. In this paper, thermal-hydraulic behavior of supercritical water in sub-channel of triangular-array rod bundle has been investigated using computational fluid dynamics（CFD） code CFX. Two cases, i.e. constant wall heat flux at cladding surface and constant volume heat density in fuel pellet, are analyzed. Results show that circumferential conduct heat transfer in cladding significantly reduces the non-uniformity of circumferential temperature and heat transfer distributions, but the conduct heat transfer is with weak effect on second flow and velocity fluctuation across the gap. Turbulence mixing at rod gap strongly depends on pitch-to-diameter ratio（P/D）. If P/D＜1.3, the mixing coefficient is in the range of 0.02～0.025. It also shows unusual behavior of mixing coefficient in the vicinity of the pseudo-critical point and needs further investigations.

Heat Transfer Characteristic of Supercritical Pressure Water in Nonuniform Heating Vertical Tube

WANG Hai-jun, TANG Ren-hu, LUO Yu-shan, HU Zhi-hong, CHEN Ting-kuan

2008, 29(4): 57-62.

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In this paper,experiment is carried out to get the heat transfer characteristic of supercritical pressure water in nonuniform heating vertical tube.The test parameters are as: p=23～30 MPa,G=600～ 1 200 kg/（m².s） and q=200～600 kW/m².The results show that for the nonuniform heating situation,the coefficient of the nonuniform heating tube can be calculated using the uniform heating tube formula with the same average heat flux;when heat transfer deterioration occurs,the wall temperature rises of nonuniform circumferential distribution of heat flux and heat transfer coefficient tend to uniformity with the increasing of Re number;at the same tube cross section the heat transfer enhancement and deterioration may occur at the same time and the heat transfer deterioration is determined by the local heat flux;the average heat transfer heating tube is lower than the uniform heating tube.

Numerical Research on Density Wave Oscillation of Two-Phase Flow in Parallel Inclined Internally Ribbed Pipes for Supercritical Pressure Boiler

HUANG Ke-xin, GAO Feng, BI Qin-cheng, LUO Yu-shan, CHEN Ting-kuan

2008, 29(4): 63-68,73.

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An instability theoretical model for multi-channel system had been developed by building one-dimensional homogeneous model and adopting nonlinear analysis for two-phase flow in vertical single pipe,supplied by Clausse and Lahey.With the same parameters as the experiment,two-phase flow density wave oscillation in parallel inclined inner ribbed pipes was analyzed and solved in this paper.The variation of the working fluid inlet velocity perturbation with time was found using the time domain method.The criteria of density wave oscillation were defined according to the convergence or divergence of the velocity.The pulse cycle of calculated results was mostly between 5 and 16 seconds,which was quite similar to the data between 7 and 19 seconds in the experiment.It is shown that the calculated results have a good agreement with the experimental data.Therefore,the method can be used to determine whether the incidence of density wave instabilities.It can also provide a reference for the safety parameters of the water wall in the supercritical pressure boiler.

Limit Load Analysis for Plates with Elliptical Corner Cracks at Hole under Combined Tension and Bending Loads

ZHU Guo-min, LIANG Li-hua, LI Rong-sheng, GAO Zeng-liang, LEI Yue-bao

2008, 29(4): 69-73.

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A global limit load solution is derived for plates with elliptical corner cracks at a hole under combined tension and bending loads,based on the net-section collapse principle.The limit load solution is compared with the results of elastic-plastic finite element analysis for the plates with elliptical corner cracks at a hole for different crack sizes,a/t = 0.2,0.4,0.6,0.8,a/c = 1.0,0.4,0.2 and different loads,λ = 0,0.25,1,∞.The results show that the analytical solutions of the global limit load are conservative and close to the elastic-plastic FE results.The maximum difference between the analytical solutions and the FEA results is less than 20%.

Investigations on Creep Strength Design Criteria for High Temperature Components on the Base of Creep Cavity Theory

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

2008, 29(4): 74-78.

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Creep failure mechanisms of high temperature components under multiaxial stress states are analyzed,and the design criteria for creep strain and stress are presented on the basis of cavity growth theory.Methods of how to calculate creep equivalent stress and strain and how to determine permissible creep stress and strain are proposed.Compared with the traditional creep design approach based on classic plastic theory,the proposed method in this paper takes into account the physical mechanism of creep failure and therefore can predict multiaxial creep behavior of high temperature components more reasonably.In the end,difficulties faced in the field of multiaxial creep strength design are analyzed and recommendations for further research are presented.

Study on Pressure Pulsation and Piping Vibration of Complex Piping of Reciprocating Compressor

XU Bin, FENG Quan-ke, YU Xiao-ling

2008, 29(4): 79-83.

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This paper presents a preliminary research on the piping vibration and pressure pulsation of reciprocating compressor piping system.On the basis of plane wave theory,the calculation of gas column natural frequency and pressure pulsation in complex pipelines is done by using the transfer matrix method and stiffness matrix method,respectively.With the discretization method of FEM,a mathematical model for calculating the piping vibration and stress of reciprocating compressor piping system is established,and proper boundary conditions are proposed.Then the structural modal and stress of the piping system are calculated with CAESAR Ⅱ.The comparison of measured and calculated values found that the one dimensional wave equation can accurately calculate the natural frequency and pressure pulsation in gas column of piping system for reciprocating compressor.

Linearized Model for Optimal Controller Design of PWR Core and Its Application

LI Hai-peng, HUANG Xiao-jin, ZHANG Liang-ju

2008, 29(4): 84-87,122.

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Based upon the perturbation theory,a Linear Time-Invariant（LTI） model of the Pressurized Water Reactor is formulated through the linearization of the nonlinear model.A Linear Quadratic Gaussian（LQG） optimal controller is synthesized using the LTI model and simulation experiments are performed.The simulation results show that the methodology of employing the linearized model for control system design is feasible and the control performance is satisfactory.

Effect ²³⁹Pu in Burnup Measurement Process in HTR-PM

ZHANG Li-guo, LI Tao-sheng, FANG Dong

2008, 29(4): 88-92.

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The portion of ²³⁹Pu in the nuclear fuel cycle of gas cooled high temperature reactor-pebble bed module（HTR-PM） is very important at the high level of burnup,which certainly influences the online burnup measurement.This problem was discussed in the paper.When the expected average burnup was 80 000（MW.d）/t（U）,the calculation result showed that the energy release from ²³⁹Pu fission contributed to the burnup of fuel pebble by 26.7% and the acitivity of ¹³⁷Cs and ¹³⁴Cs from ²³⁹Pu fission is about 27.2% and 23.2%,respectively.Further analysis also showed that it is better to determinate the burnup by the activity of ¹³⁷Cs in the pebble than by the activity ratio of ¹³⁴Cs/¹³⁷Cs.

Study on PID Control System Based on Fuzzy Self-Adaptive Parameter-Adjustive Technique of Once-Through Steam Generator

ZHANG Yu-sheng, GUO Li-feng, CAI Meng

2008, 29(4): 93-96.

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A three-parameter fuzzy self-adaptive-adjustive Proportional-Integral-Differential（PID） control system is designed in this paper based on the full study of the characteristics of once-through steam generator. The fuzzy self-adaptive technique as well as three-parameter control system is introduced to normal PID control system. Simulation result indicates that this control system can give effective control over once-through steam generator by the analysis of control simulation result.

Research on Synchronism Technique Based on Field Programmable Gate Array

LU Yi, LI Meng, RONG Ru

2008, 29(4): 97-99.

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The research on sychronism technique is introduced in this paper.The synchronous machine based on Field Programmable Gate Array（FPGA） is combined with the integrate circuit and transistor,to realize multiplex pulse and step-signals synchronized with input signal.The technical target has been achieved.It is proved by experiment that the reliability and stability of this synchronous machine can meet the requirements of physical experiment.

Study on Active Magnetic Bearing Controller for HTR-10 Helium Turbine Rotor

LI Hong-wei, ZHAO Lei, SHI Lei, YU Su-yuan

2008, 29(4): 100-103,116.

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The active magnetic bearing （AMB） will be applied to suspend the turbine rotor and the generator rotor of the helium gas turbine in HTR-10. Since the rotaion speed of the turbine rotor under normal conditions is higher than that of two order flexible critical rotation speed, the control method of the AMB system should be explored to ensure that the turbine rotor can be well controlled. A small turbine rotor- AMB experimental system was built to study the control method, and the controller was designed by simulation and experiment. Using PID and phase compensation methods, two controllers were designed: one with low stiffness and the other with high stiffness. Controlled by these two controllers separately, the experimental turbine rotor can be suspended stably and its speed successfully increased higher than that of the two orderflexible critical rotation, which reached 450 r/s in maximum. Experiment showed that compared with lower stiffness controller, the vibration amplitude of the rotor reduced significantly under the action of high stiffness controller at 50~300 r/s. The experimental results indicate that the high stiffness controller has better performance than the low stiffness controller.

Development of Emergency Operation Procedure System for Nuclear Power Plants

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

2008, 29(4): 104-107,116.

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An Emergency Operation Procedure System（EOPS） is developed in the embedded real-time operation system VxWorks in this paper.The EOPS takes the advantages of computerized procedures technology and can provide the detailed and comprehensible emergency procedures.The structure of EOPS is introduced and the application of EOPS is exampled with LOCA.The feasibility of the system is validated on the full scale simulator,and the validation showes that the load and pressure for the workers can be reduced and the safety of NPP can be inhanced..

Study on Mitigating Capability of High-Pressure Safety Injection for Large Break LOCA in PWR

ZHANG Long-fei, ZHANG Da-fa, XU Jin-liang

2008, 29(4): 108-111.

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Talking a typical Westinghouse three-loop pressurized water reactor （PWR） as reference plant and using the PWR severe accident analysis platform based on RELAP/SCDAPSIM code, best estimate calculation of hot leg large break LOCA of 25 cm without mitigating measures is performed. The mitigating capability of high-pressure safety injection to the accident is studied when peak core temperature reaches 1 100 K, 1 300 K and 1 500 K respectively. The results show that the time of starting high-pressure safety injection plays an important role in the accident progression. Injection during early stage will prevent core from melting effectively. However, injection during later stage may deteriorate the progression of severe accident and result in accelerated melting.

Study on Core Melting Accident Induced by One Stuck-Open Pressurizer Safety Valve

WU Peng, YANG Yan-hua, LIN Meng

2008, 29(4): 112-116.

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The core melting accident in DaYa Bay NPP, induced by the total loss of feedwater accident with one stuck-open pressurizer safety valve, is analyzed by using SCDAP/RELAP5 computer code. The analytical results of this base case indicate that it leads to core melting, and has the potential probability of high pressure core melting risk. At the same time, study on the mitigation measures indicates that the feed-bleed measure can cool the core effectively.

Research on Heat Removal Capability for Passive Moderator Residual Heat Removal System of TACR-1000 when Station Black-Out Accident

YAN Lin, JIA Bao-shan, LIAN Hai-bo

2008, 29(4): 117-122.

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To evaluate the effectiveness of the Passive Moderator Residual Heat Removal System（PMRHRS）,CATHENA（Canadian Algorithm for Thermal hydraulic Network Analysis） code is used to simulate its cooling capability under normal condition and the lost of flow accident condition.And the result of steady state is obtained by the simulation and calculation for the Moderator Cooling System（MCS）,which is used as the initial value for the transient state analysis.The heat removal capability of the PMRHRS is then calculated and the result is initially analyzed to prove that the PMRHRS can keep the reactor safe.

Experimental Research on Heat Transfer in Process of Starting Up of Density Lock

WANG Sheng-fei, YAN Chang-qi, GU Hai-feng, CAO Xia-xin

2008, 29(4): 123-126,139.

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Experimental studies of heat transfer in the start up of density lock are carried out, respecitvelywithout disturbance and with different disturbances. The research indicates that, stratification can be dividedinto three types, i.e., strong stratification, weak stratification and no stratification. Both the former two casescan restrain heat transfer, moreover, the heat transfer in strong stratification is less than that in week stratification and the heat would directly go through the density lock continuously in the third case so that the density lock is invalid.

Application of MCNP Code in Shielding Calculation of Minitype Fast Reactor

HE Ke-yu, HAN Wei-shi

2008, 29(4): 127-130,144.

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An accurate shielding calculation model has been set up for the minitype sodium-cooled fast reactor （MFR） based on MCNP code and particular calculation of its primary shielding parameters has been carried out. The results indicate that the photon and neutron flux density of MFR has rapidly fallen to a low-level. The material for the shielding layer outside of main container is primarily of carbon steel, which can be design as a shielding structure satisfing the safety code. The sodium activation in primary circuit is extremely limited and it is simple to shield from. Both the output of helium in reflecter and burn up of boron-10 in control rod are very small. These materials can be used for several cycle lives.

Qualification Test on Class 1E Electrical Components in Nuclear Power Plant

WANG Guang-jin, LIU Yan, LIU Jiang-yan, ZHENG Lan-jiang, ZHOU Tian

2008, 29(4): 131-134.

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Based on the standard and technical data, this paper introduced the methods and principle for the qualification test on class 1E electrical component in nuclear power plants.The procedures and methods for the qualification of components in nuclear power plants and the test conditions in China were analyzed in detail. The study showed that the model test is the main test method for the class 1E electrical component in China at present. The procedure for the qualification test, required documents, experiment item and related acceptance criteria were also proposed in the papter.

Diagnosis Method for Fuel Failures in Pressurized Water Reactor Nuclear Power Plant

LI Lan, YANG Hong-run

2008, 29(4): 135-139.

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Fuel performance during the operation of a nuclear power plant is a major constraint on operation management.If the performance and status of fuel rods is known before the shutdown,an appropriate fuel detection management policy can shorten the reactor outages.A diagnosis method for analyzing reactor coolant activity in order to determine the number,size and location of fuel clad failures is developed,and based on DAYA Bay nuclear power plant unit 1 cycle 2 operation data,a failure diagnosis for U1C2 fuel assembly has been carried out.It is showed that the diagnosis results are very similar to the results measured.

Study and Development of Equipment Supervision Technique System and Its Management Software for Nuclear Electricity Production

ZHANG Li-ying, ZOU Ping-guo, ZHU Cheng-hu, LU Hao-liang, WU Jie

2008, 29(4): 140-144.

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The equipment supervision technique system, which standardized the behavior of supervision organizations in planning and implementing of equipment supervision, is built up based on equipment supervision technique documents, such as Quality Supervision Classifications, Special Supervision Plans and Supervision Guides. Furthermore, based on the research, the equipment supervision management information system is developed by Object Oriented Programming, which consists of supervision information, supervision technique, supervision implementation, quality statistics and analysis module.

2008 Vol. 29, No. 4