核动力工程

Design of Digital Reactor Protection System of Ling'ao Phase II NPP

LIU Hong-chun, WANG Tao-tao, WANG Hua-jin, ZHOU Ji-xiang, LIU Guang-ming, XU Dong-fang

2008, 29(1): 1-4,9.

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The Reactor Protection System of Ling'ao Phase II NPP is the first digital reactor protection system which is designed by China.In this paper,the general architecture,the design characteristics,the periodic test and the self-monitoring of the Reactor Protection System are introduced.

Design of Inadequate Core Cooling Monitoring System in Qinshan Phase II Extension Project

HE Zheng-xi, LI Bai, WU Jun, ZHANG Fan

2008, 29(1): 5-9.

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Since the equipment of Inadequate Core Cooling Monitoring System (ICCMS) applied in Qinshan phase II project has not been produced any longer,TXS will be applied in ICCMS as an alternative choice in Qinshan phase II extension project.This paper gives a generally description of the structure and theory of ICCMS in the extension project.

Analysis of Effect of Electromagnetic-Disturbance on Sensitive Instrument Control Equipments in Daya Bay Base

QU Yue-qi, LU Wenyue, MAO Xiaoming, YANG Guang, ZHANG Shuo, YU Liang

2008, 29(1): 10-13.

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This paper briefly introduced the generation,preventive methods and the experience feedback learned from foreign nuclear power stations about electromagnetic-disturbance.At the same time,considering the results of electromagnetic-disturbance test on the site of Lingao Nuclear Power Station (I),this paper analyzed the effect of electromagnetic equipments in Daya bay base on the sensitive instrument equipments,and proposed some advices.

Design Method of Control System for HTGR Fuel Handling Process with Control Petri Net

HAN Zan-dong, LIU Ji-guo, LUO Sheng

2008, 29(1): 14-18,24.

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As a complex mechanical system,the fuel handling system (FHS) of pebblebed high temperature gas cooled reactor (HTGR) is with the features of complicated structure,numerous control devices and strict working scheduling.It is very important to precisely describe the function of FHS and effectively design its control system.A design method of control system based on control Petri net (CPN) is introduced in this paper.By associating outputs and operations with places,associating inputs and conditions with transitions,and introducing macro-places and macro-actions,the CPN realizes hierarchy design of complex control system.Based on the analysis of basic functions and working flow of FHS,its control system is described and designed by CPN.According to the firing regulation of transition,the designed CPN can be easily converted into LAD program of PLC,which can be implemented on the FHS simulating control testbed.Application illuminates that proposed method has the advantages of clear design structure,exact description power and effective design ability of control program,which can meet the requirements of FHS control system design.

Improvement of CATIA2 Code Used in Optimization Design for Digital Instrument and Control System of NPP

ZHANG Ying, CHEN Zhi, ZHOU Zu-jian, ZHANG Fan, ZHANG Xiao-hua, ZHANG Wen-qi

2008, 29(1): 19-24.

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In order to meet the requirements of the optimization design work for the digital instrument and control system of the nuclear power plant (NPP),the transient simulation program for PWR,CATIA 2 code,has been improved.The main improvements are that the digital sampling module,the digital processing time steps of the ΔT protection channels and the sample time of the input parameters for the ΔT protection channels are introduced in the CATIA 2 code.A new over temperature setpoint equation module according to the digital technology is provided.By analyzing and comparing the numerical simulation results,the improvements are proved to be reasonable and feasible.

Quality Control for Automatic Submerged-Arc Welding on Containment Steel Liner of Chashma Nuclear Power Plant Project

MA Xin-chao

2008, 29(1): 25-29.

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The paper introduces the basic constitution of containment steel liner to Pakistan Chashma nuclear power plant (C-2) project,and analyses the origin for the endless crack in the welding joints of SAW.To prevent occurring of endless cracks in SAW,well match of the main welding parameters is the base way to eliminate the weld of big reinforcement and small width.Correct chose and reuse of granular of welding flux is important for reducing of the blowhole and pit on weld surface.Secondary cutting can mitigate the deformation of the whole plate after welding.

Preliminary Design of Hydrogen Decreasing System in Large Dry Containment

LIN Ji-ming, LIU Bao-ting

2008, 29(1): 30-34.

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In severe accident of PWR,large amount of hydrogen may accumulate in the containment,combustion or detonation may occur and challenge the integrity of containment.Passive autocatalystic recombiners (PARs) should be installed to mitigate the hydrogen risk.Aiming at Lingao phase 2 nuclear power plant,using MELCOR and TONUS,a preliminary design of hydrogen mitigation system has been given.Different hydrogen mitigation systems are also compared in this paper.

Numerical Simulation of Optimal Nozzle-to-Throat Clearance of Jet Pump

LONG Xin-ping, CHENG Qian, HAN Ning, ZHANG Gai-lan

2008, 29(1): 35-38.

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The interior flow-field of jet pump was simulated by FLUENT and the effect of the nozzle-to-throat clearance,which is one of the most important structure parameters,on the performance of jet pumpwas analyzed.The characteristics of jet pump with two different area ratios were calculated under theconditions of different nozzle-to-throat clearances.Comparison between the efficiency curves of jet pumpswith various nozzle-to-throat clearances revealed that the maximum efficiency of the jet pump occurred whenthe nozzle-to-throat clearance is equal to the nozzle diameter.Under a guideline of declining 4% from themaximum efficiency point,the optimal scale of nozzle-to-throat clearance was found to locate between 0.5 to1.5 times of the nozzle diameter.

Grey Fuzzy Evaluation on Technical Condition of Canned Motor Pump

CHEN Ling, CAI Qi, CAI Zhang-sheng

2008, 29(1): 39-41,45.

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It is difficult to assess the technical condition of the canned motor pump because of its various factors and insufficient monitor information.Considering the main failure modes and phenomena determined by FMEA,the condition monitoring is carried out correspondingly.Based on the condition monitoring results,the technical condition is comprehensively assessed by the grey fuzzy evaluation.The method gives a new approach to assess the technical condition of complicated equipments.A numerical example is given to demonstrate the rationality and applicability of the proposed method.

Development of Control Mechanism for Releasing Molten Droplet in Experiment of Molten Fuel Coolant Interactions

LI Liang-xing, LI Hui-xiong, CHEN Ting-kuan, SHAO Jing

2008, 29(1): 42-45.

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In the experiment of interaction of high temperature molten droplet and coolant,the releasing control of the molten droplet is vital for the whole experiment.Base on the mechanical control device in the previous experiments,an automatic device of the molten droplet is developed in this paper.The molten droplet is released when an instantaneous pulse from the automatic control circuit is delivered to the electromagnet.The improvement of releasing the molten droplet simplifies the experiment procedure,and advances the repeatability and the accuracy of the experiment.

Analysis of Seismic Response of a Polar Crane in Nuclear Power Plant

LI Zeng-guang, WANG Jiong, WU Tian-xing

2008, 29(1): 46-49.

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The seismic response is analyzed for a polar crane used in nuclear power plant.A 3-D finite element model for the polar crane structure is developed using the ANSYS codes.Based on the modal analysis,the seismic response of the crane structure is calculated to an input of the seismic spectrum at the plant floor,where the polar crane is installed and operates.The results show that the crane is generally safe from the seismic input in terms of the structure strength,whereas the structural responses in the horizontal direction are large due to the horizontal seismic input,as the first order natural frequency of lateral bending of the structure is close to the frequencies where the peaks of the seismic spectrum occurs in the horizontal direction.

Comparison of Beam Element and Shell Element in Analyzing Inherent Vibration of Structures

TIAN Jin-mei

2008, 29(1): 50-52,80.

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Finite element models of tube structures are set up using ANSYS with beam 188 element and shell63 element respectively.The computing programs are written by means of APDL language,the free vi-bration characteristics of tube structures with length-to-diameter ratios of 4~20 are computed.Also,the cor-responding inherent frequencies and modes are analyzed.The results show that as to tube structures with length-to-diameter larger than 10,the beam element of ANSYS based on Timoshenko beam can meet our re-quirements;but as to tube structures with length-to-diameter smaller than 6,in order to improve the accuracy,elements which are more close to real structures such as shell element or solid element should be used ac-cording to practical engineering.

Performance Evaluation of Different Types of Nuclear Fuels Loaded in Fast Reactor Core for A Long Time Operation

HU Yun, XU Mi

2008, 29(1): 53-56.

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By using a typical fast reactor core model formed by hexagonal lattice cell,this paper studied the performance of different types of nuclear fuels,which are loaded respectively as fuel in this fast reactor core model for a long time operation,and analyzed the spent fuel compositions of different fuel types at EOL.The results indicated that,in the case of same lattice cell and similar initial reactivity,the burnup reactivity loss of metallic fuel is the smallest,followed by nitride fuel,carbide fuel and finally oxide fuel,while within same chemical form,fuels driven by Pu provide smaller reactivity loss compared to fuels driven by ²³⁵U.Analysis of spent fuel composition shows that metallic fuel also exhibits smallest TRUs mass (averaged by initial fuel mass) of spent fuel,and then followed by oxide fuel,nitride fuel and carbide fuel,while at the same time,compared to fuels driven by ²³⁵U,Pu based fuels were found to discharge more TRUs mass because of the increase of initial Pu loading mass,and thus lower percent of fissile materials in spent fuel.In terms of neutronics UZr fuel is an ideal fuel for long life fast reactor core.

Experimental Study on Local Heat Transfer Characteristics of Porous Media with Internal Heat Source

ZAN Yuan-feng, WANG Tao-tao, XIAO Ze-jun, WANG Fei, HUANG Yan-ping

2008, 29(1): 57-60.

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Model of porous media with internal heat source is established.The model uses water as flowing media,and the stainless steel test section is packed with steel spheres in manner of regular triangle,respectively.The armoured resistance wire is inserted inside the steel sphere.On the basis of the experimental model,many parameters of the local heat transfer characteristics including current velocity and wall temperature of steel sphere are measured.The experimental results show that the coefficient of heat transfer scarcely changes with pressure.The coefficient of heat transfer increases with the surface heat flux of steel sphere..When raising the inlet temperature of the cooling water,the coefficient of heat transfer presents the descending trend.In addition,the influence of entrance effect on heat transfer is discovered in the experiment,which is much less than the liquid flow in the light tube.After experiment data are analyzed and processed,the relation model of heat transfer on local heat transfer characteristic of porous media with internal heat source was described with a power-law-equation.The deviations between calculation and experimental values are within ±10%.

Effect of Several Fillers on Brazing Metal Strength and Interface of Titanium Alloy and Stainless Steel Brazing Joint

YANG Jing, LAI Xu-ping, ZHU Chang-gui, ZHU Jin-xia, LIU Xiao-rong, YANG Jun

2008, 29(1): 61-65.

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Four kinds of silver base brazing materials were adopted for fabricating brazing joints of titanium alloy and stainless steel.The mechanical properties of brazing metal at contact face was measured and the fracture morphology and structure of interface were studied by mechanical test,metallographic examination,SEM analysis and electron probing analysis.The result shows that the strength of brazing metal at stainless steel/Ag95CuLi/Titanium alloy was 220 MPa,242 MPa at stainless steel/Ag88Al10MnSi/Titanium alloy,123 MPa at stainless steel/Ag85Al8Sn/Titanium alloy,and 280 MPa at stainless steel/Ag85Al8SnNi/Titanium alloy.The fragile phase was easy formed in the diffusion part of stainless steel/Ag95CuLi,and cracking in the stainless steel/Ag88Al10MnSi.And there is a wonderful coalescence on metallurgy between the brazing materials and titanium alloy or stainless steel.

Study on Initial Oxidation of Uranium Surface with Implantation of C Ions

WANG Qian, MENG Da-qiao, LIU Ke-zhao, XIAO Hong, ZHANG Hou-liang

2008, 29(1): 66-69,95.

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The initial oxidation of uranium and uranium samples which were overlapped energy ionimplanted with C ions was studied respectively by Auger electron spectroscopy (AES).The results showed that the clean uranium surface can be oxidated at high vacuum atmosphere.and when exposed dose of oxygen was 40L,the surface was covered with UO2.The study indicated that the antioxidation properties of uranium surface had been improved apparently after ion implantation.

Study of Iodine Recovery with Platinum-Active Carbon from Nitric Acid Solution

DENG Qi-min, LI Mao-liang, CHENG Zuo-yong

2008, 29(1): 70-72.

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Platinum-Active Carbon (Pt-C) was synthesized and its adsorption and desorption properties in low acidity nitric solution were discussed.It showed that Pt-C can absorb I^- and IO₃^- with high ex-change capacity in nitric acid solution,and the recovery rate of I^- and IO₃^- is more than 90%,thus Pt-C can be used for iodine recovery in low acidity nitric solution.

Hydriding of Zirconium-Niobium Alloy

XU Hai-sheng, LAN Guang-you

2008, 29(1): 73-75.

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The zirconium-niobium alloy is hydrided at 880℃.And when zirconium hydride reaches its hydrogen saturation point at that temperature,hydrogen has been continuously supplied to the hydriding fur-nace during the process of slowly cooling.This method can progressively increase the hydrogen content of zircloy hydride and effectively prevent hydride from cracking.The results show that the H/Zr atom ratio of zirconium hydrides is above 1.80 and the samples have no cracking.During the hydriding process,the niobium which is rejected from the zirconium hydride is present as a fine,uniform dispersion.The H/Zr atom ratio is depended on the hydriding temperature and the pressure of hydrogen.It is very important to prevent zirconium hydride from cracking by controlling the rate of cooling and the flow of hydrogen.The X-ray diffraction and metallography analysis results show that the hydride phase is a single ε-phase and the morphol-ogy of ZrHx (x>1.80) appears as a banded,twin structure.

Investigation on Calculation Method of Mean Temperature Difference in Heat Exchanger Thermodynamic Calculation

LU Guang-yao, WANG Jing, SUN Zhong-ning

2008, 29(1): 76-80.

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The calculation method for the logarithm mean temperature difference (LMTD) and the arithmetic temperature difference was analyzed.Heat exchange is calculated by two methods of logarithm mean temperature difference and measuring of wall temperature,and calculation results were analyzed.Ex-periment showed that in the calculation of the convective heat transfer coefficient,the results gained by these two methods had large differences,especially in low Reynolds number region.The difference of the calculation results came from the distinctness between LMTD and AMTD.In the turbulent flow area,the difference became small and LMTD can be adopted to analyze the convective heat transfer characteristics in the turbulent flow area in the engineering calculation.

Effects of Thermo-Hydraulic Parameters on Flow Oscillation in Double Narrow Rectangular Channels

LI Hong-bo, HUANG Yan-ping, LU Dong-hua, WANG Yan-lin

2008, 29(1): 81-86.

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Flow instability in parallel rectangular channels is one of the important factors to affect the operation safety of the flat-plate-type fuel assembly cores.The experiment of flow oscillations in double narrow rectangular channels has been carried out in the thermo-hydraulic loop in NPIC.The results of experimental research of thermo-hydraulic parameters on characteristics of flow oscillation in double narrow rectangular channels show that:(1) With the increasing of inlet subcooling,the limit heat flux,amplitude and period of oscillation are increased;and effects of inlet subcooling on critical quality of oscillation are of ambiguity.(2) With the increasing of inlet flow velocity,the limit heat flux and amplitude of oscillation are increased;and the critical quality and period of oscillation are reduced.(3) With the increasing of system pressure,the limit heat flux and critical quality of oscillation are increased,the amplitude of oscillation is reduced;and effects of system pressure on period of oscillation are.of ambiguity.(4) Based on the stability boundary map obtained by using N_sub and N_pch,an experimental correlation of stability boundary in double narrow rectangular channels has been obtained as follows:N_pch=3.1419 N_sub+10.014.

Theoretical Investigation on Dryout Point of upward Annular Flow in Narrow Gap with Bilateral Heating

DUAN Feng, SU Guang-hui, QIU Sui-zheng, XIAO Zejun, HUANG Yan-ping

2008, 29(1): 87-90,105.

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Based on the separated flow model,a theoretical three-fluid model predicting for dryout point of annular upward flow in a vertical narrow annuli with bilateral heating has been developed in the this paper.The predicted results agree well with the experimental data.The numerical results show that:a) when the dryout point occurs on the inner tube,critical quality will increase with decreasing the curvature of tube and gap size for a fixed heat flux of outer tube.When the dryout point occurs on the outer tube,the case is reverse for a fixed heat flux of inner tube;b) the influences of pressure and mass flow rate on critical quality is very slight when the gap size is smaller than 0.5mm or the outer diameter of inner tube is larger than 20mm with a fixed gap size.

Numerical Study on Single-Phase Flow Field in Rod Bundles with Spacer Grids

TIAN Rui-feng, MAO Xiao-hui, WANG Xiaojun, ZHU Weibing

2008, 29(1): 91-95.

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3-D single-phase flow field in rod bundles with spacer grids was studied using numerical methodology.Using hybrid grids technique,employing standard k-ε model and SIMPLEC algorithm,the axial velocities obvious near the spacer grids than lateral velocities,it also influence the resistance characteristic obvious.Mixing vane affects lateral velocities much,and blends the axial velocity.

Experimental Investigation on Characteristics of Mechanical Pumped Two-Phase Cooling System under Periodic Temperature Boundary Conditions

LIU Jie, PEI Nian-qiang, GUO Kai-hua, HE Zhen-hui, LI Tingxun, GU Jian-ming

2008, 29(1): 96-100,128.

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This paper analyzes the work principle,mathematical model and main parameters for the two-phase flow cooling system driven by mechanical pump.Temperature distribution,resistance and flow mass of main components in the active two-phase cooling system driven by mechanical pump are experimen-tally studied.Heat transfer of the system is calculated and analyzed.The study results indicate that:when the temperature wave of the condensation boundary approaches 30℃,the difference between inlet and outlet temperatures can be kept less than 0.3℃ and the temperature change with time is less than 0.4℃,along the 10 m evaporation section.Analysis indicates that the two-phase flow cooling system driven by mechanical pump is of well isothermal characteristics and stable heat transfer.Calculation and analysis also indicate that this system can realize larger heat transfer with smaller energy consumption,which improves the work capability of the active heat control system.

Assessment of Models for Onset of Flow Instability Experimental Data in Narrow Rectangular Channel

WANG Yan-lin, HUANG Yan-ping, LU Dong-hua

2008, 29(1): 101-105.

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Assessment of models for Onset of Significant Void and Onset of Flow Instability was carried out against narrow rectangular channel (1 000 mm×25 mm×2 mm) experimental data in the condition of:P=1~15 MPa,G=500~2 000 kg/(m².s),△T_sub,in=20~100℃,q=40~1 000 kW/m².The results showed the correlations of Saha-Zuber,Levy and Bowring for OSV and the correlations of W&F,Lee&Bankoff and Kennedy for OFI predicted the experimental results within ±20%,but predicted OFI obviously lower at low heat flux and higher results at high heat flux.A new purely empirical correlation was developed by comparing the heat flux leading to OFI with that leading to saturation:qOFI=1.95q_sat^0.87.The deviation is within ±15%.It is also suitable for other types of channels and parameters.

Preliminary Study on Heat Transfer Characteristics of Stratified Fluid in Density Lock

GU Hai-feng, YAN Chang-qi

2008, 29(1): 106-109,120.

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By the method of visible observation,experimental study on heat transfer characteristics of stratified fluid is made in three different pipes,at the same time,computational model on heat transfer is built,and mechanism of heat transfer in density lock is analyzed.The results show that the work fluid can be divided into three zones from top to bottom:mixing layer,interface layer,and conduct layer.In mixing layer heat is mainly transported by convection,and transported by conduct in interface layer and conduct layer.In addition,the result of study on different pipes indicates that the honey comb channel in density lock can efficiently curb the disturbance,lessen the thickness of mixing layer and decrease the heat transfer through density lock.

Experimental Study on External Condensation Heat Transfer Characteristics of Bellows

FENG Dian-yi, HU Jian-sheng

2008, 29(1): 110-114.

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Flow model and heat transfer of condensation flow outside of bellows have been theoretically and experimentally studied.The formula for calculation of condensation heat transfer coefficient was deduced,and corrected through experiment.The calculation results are accordant with the experimental ones,and the errors is less than 10%.The effect of bellows structure parameters and pipe diameter on the enhancement heat transfer has been investigated.It is found that in the steady flow region,the average condensation heat transfer coefficient in a bellows is 3~5 times than that in a straight tube under the same conditions,and when considering the increasing in heat transfer area,the effectiveness of enhancement heat transfer is 5~7 times than that in a straight tube.To facilitate the engineering design and application of bellows,the formula for the calculation of the average heat transfer coefficient of a fluid in a bellows was also given.

Identification Method of Gas-Liquid Two-Phase Flow Regime Based on Image Wavelet Packet Information Entropy and Genetic Neural Network

ZHOU Yun-long, CHEN Fei, SUN Bin

2008, 29(1): 115-120.

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Based on the characteristic that wavelet packet transform image can be decomposed by different scales,a flow regime identification method based on image wavelet packet information entropy feature and genetic neural network was proposed.Gas-liquid two-phase flow images were captured by digital high speed video systems in horizontal pipe.The information entropy feature from transformation coefficients were extracted using image processing techniques and multi-resolution analysis.The genetic neural network was trained using those eigenvectors,which was reduced by the principal component analysis,as flow regime samples,and the flow regime intelligent identification was realized.The test result showed that image wavelet packet information entropy feature could excellently reflect the difference between seven typical flow regimes,and the genetic neural network with genetic algorithm and BP algorithm merits were with the characteristics of fast convergence for simulation and avoidance of local minimum.The recognition possibility of the network could reach up to about 100%,and a new and effective method was presented for on-line flow regime.

Modeling and Simulating System for OTSG Feedwater Control

SUN Jian-hua, WANG Wei, ZHAO Fuyu, ZHANG Xiao-hui

2008, 29(1): 121-124,128.

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The marine nuclear power plant with Once-Through Steam Generator (OTSG) is a kind of controlled object with multi-variant and strongly coupling features.A modeling and simulating system for OTSG feedwater control is introduced in this paper.The physics equipment of control system acquires parameter signal from the real-time simulation system,and the control signal is sent to servo-actuators.The results of experiment with close-loop control on the modeling and simulating system indicate that the feedwater control system has good load tracking performance.The study would provide methodological guidance for practical design and implementation of OTSG control system.

Acceleration Method for Neutron Transport Equation with Highly Anisotropic Scattering

SUN Xing-guang, WU Hong-chun, SHEN Zhi-jun

2008, 29(1): 125-128.

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SN method is wildly used to solve neutron transport equation,but SN method is very slow with highly anisotropic scattering.In this paper,the modified P_N synthetic acceleration (MPSA) method is used to accelerate SN method,and applied to the code of ANISN which is internationally used.MPSA method not only can accelerate the computation with low-order of angular flux moments,but also with high-order of angular flux moments.So MPSA method is more efficient than DSA method.Numerical results for the test problems demonstrate that MPSA method is quiet efficient and robust,especially for the problems with highly anisotropic scattering.

2008 Vol. 29, No. 1