核动力工程

Design of Reactor Nuclear Measurement Systems in Ling’ao Nuclear Power Station Phase Ⅱ

LI Wenping, YANG Daibo

2012, 33(2): 1-4.

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This paper analyzes the characteristics of Reactor Nuclear Measurement Systems,including Nuclear Instrumentation System（RPN）,In-core Neutron Fluence Rate Measurement system（RIC）,LOCA Surveillance System（LSS）,and introduces the function distribution and interface design between the Nuclear Measurement Systems and the Digital Instrument Control System（DCS）.Based on the advantages of DCS,3 different function distribution and interface design schemes are taken in Ling’ao Nuclear Power Station Phase Ⅱ for different function requirements and characteristics of RPN,RIC and LSS.Consequently,these design schemes lead to a good result in fault diagnosis and logic processing.

Analysis and Test of Respond Time of Nuclear Power Plant Digital Control System to Reactor Trip

WANG Jining, ZHOU Aiping, QIE Yongxue, ZHI Yuan

2012, 33(2): 5-10.

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The paper gives a brief introduction on the structure of nuclear power plant reactor protect system and the data processing link to actuate the reactor trip.Theoretical analysis of the response time of reactor trip processing is conducted.Test philosophy is established and relative test device is designed,and the test work is conducted.The statistical analysis of the experimental data from test work shows that,the experimental maximum data of reactor trip response time is 144.8 ms while the theoretic maximum data is 149.1 ms.The experimental data accords with the normal distribution,of which the average value is 120.6 ms,and the variance is 90.1 ms.

Safety Analysis of Tritium Processing System Based on PHA

FU Wanfa, LUO Deli, TANG Tao

2012, 33(2): 11-14.

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Safety analysis on primary confinement of tritium processing system for TBM was carried out with Preliminary Hazard Analysis.Firstly,the basic PHA process was given.Then the function and safe measures with multiple confinements about tritium system were described and analyzed briefly,dividing the two kinds of boundaries of tritium transferring through,that are multiple confinement systems division and fluid loops division.Analysis on tritium releasing is the key of PHA.Besides,PHA table about tritium releasing was put forward,the causes and harmful results being analyzed,and the safety measures were put forward also.On the basis of PHA,several kinds of typical accidents were supposed to be further analyzed.And 8 factors influencing the tritium safety were analyzed,laying the foundation of evaluating quantitatively the safety grade of various nuclear facilities.

Design and Development of Virtual Machine Software for Safety Control System TXS in Nuclear Power Plants

LENG Shan, LIU Chun, LI Shu, CHENG Junjie, ZHANG Caike

2012, 33(2): 15-20.

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Based on the analysis of digital I＆C system TXP/TXS of the large PWR nuclear power plants,this paper takes the safety control system TXS as the simulation object,and designs and develops the DCS virtual machine software VTXS（Virtual TXS） on the platform of Windows,for the application together with the process control system TXP.Adopting the method of object-oriented modeling and modularization program design,using technologies such as multithreading and multiprocess-communication,by the basic way of automatic code analysis and data code translation and with Visual C++ platform as the developing environment,VTXS recreates the functions about safety control of real TXS with high fidelity in the form of software.

Effect of Logic Degradation on Reliability of Digital Reactor Protection System

LI Mingli, SHI Guilian, TANG Huan

2012, 33(2): 21-24.

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The paper primarily discussed the advantages of the digital reactor protection systems（RPR） compared to the analog system and the effect of the voting logic degradation on the system reliability.Based on the current common four-channel reactor protection system and the traditional reliability block diagrams（RBD） technology,two system reliability models were established and different logic degradation cases were discussed.The results showed that,the digital system is better than analog systems,which logic degradation can reduce the system risk when the reliability of system is weakened and the diagnostic coverage（DC） is large.DC contributes greatly to the system reliability.This paper also provided a method to obtain the basic data for PSA of whole system or plant.

Reliability Analysis of Repairable System Based on GO-FLOW Methodology

WU Guangjiang, WANG Yong, SHANG Yanlong, YAN Canbin

2012, 33(2): 25-29.

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A quantitative analysis method named GO-FLOW is introduced to analyze the reliability of system with priority in maintenance and the amount of repairman limited.Approximate formulas model that can be applied to the GO-FLOW calculation is derived for the reliability parameters of repairable assembly.Then the model’s feasibility is validated,and its error is analyzed.An example of redundancy pump component is presented,and the result achieved by GO-FLOW is compared with that by GO methodology.The results show that GO-FLOW Methodology can be used for quantitative analysis of this sort of repairable system;The model of GO-FLOW is effective and the algorithm is more convenient compared with GO methodology.

Estimation of Functional Failure Probability of Passive Systems Based on Adaptive Importance Sampling Method

WANG Baosheng, WANG Dongqing, JIANG Jing, ZHANG Jianmin

2012, 33(2): 30-36.

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In order to estimate the functional failure probability of passive systems,an innovative adap-tive importance sampling methodology is presented.In the proposed methodology,information of variables is extracted with some pre-sampling of points in the failure region.An important sampling density is then con-structed from the sample distribution in the failure region.Taking the AP1000 passive residual heat removal system as an example,the uncertainties related to the model of a passive system and the numerical values of its input parameters are considered in this paper.And then the probability of functional failure is estimated with the combination of the response surface method and adaptive importance sampling method.The numeri-cal results demonstrate the high computed efficiency and excellent computed accuracy of the methodology compared with traditional probability analysis methods.

Study on Anti-Seismic Test of Control Rod Driving System Suspended by Magnetic Force

ZHANG Zhihua, QIAN Dazhi, ZHANG Zhengming, WU Xinxin, XU Xianqi, HUANG Hongwen, HU Xiao

2012, 33(2): 37-41.

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To verify the stability,reliability and security function in extreme conditions,the anti-seismic test of control rod drive line was conducted.Drop-time of control rod drive line in different earthquake intensities was got.The response and strain values of control rod drive line acceleration on SL-1,SL-2 level were measured.Safety functions of control rod drive line were validated in different work conditions.Anti-seismic test data shows that the driving system can keep the structure’s integrality and realize operation function under OBE and SSE.

Seismic Tests and Analysis of HTR Graphite Single Column Model

TIAN Qing, SUN Libin, WANG Haitao, SHI Li, WANG Hongtao, HU Yuqin, ZHANG Zhensheng

2012, 33(2): 42-46.

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Consisting of graphite bricks mainly,the HTR core structure exhibits a complex dynamic behavior in the seismic load.Graphite single column model is set up based on the design of the HTR-PM to conduct the shake table tests in different boundary conditions.White noise wave and swept sine wave are used for the dynamic characteristic exploration tests and artificial seismic wave for functional verification tests.The acceleration data of the model is obtained.Further,the first natural frequency,damping coefficient,acceleration amplification factors and displacements are obtained on the basis of acceleration analysis.The result shows that the graphite single column model is with an obvious non-line performance.In a free state,its first natural frequency is between 1 and 5 Hz.The relative displacements between most adjacent bricks are below 5 mm,which meets the requirements.

Mechanical Analysis of Nuclear Safety Class Ⅱ Pneumatic Ball Valve

WANG Wei

2012, 33(2): 47-50.

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This paper analyzed the mechanics of a nuclear safety class Ⅱ pneumatic ball valve designed by a valve manufacturer,with ANSYS finite element program.The loads considered in the analysis included gravity,internal pressure,nozzle limit load and earthquake.After the analysis,the paper evaluated the valve according to the standard of ASM and technical specifications of AP1000 nuclear class valve.The calculations showed the design of the pneumatic ball valve can meet the requirement of ASME regulations and related technical specifications.

Efficient Approach for Simulating Response of Multi-Body Structure in Reactor Core Subjected to Seismic Loading

ZHANG Hongkun, CEN Song, WANG Haitao, CHENG Huanyu

2012, 33(2): 51-55.

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An efficient 3D approach is proposed for simulating the complicated responses of the multi-body structure in reactor core under seismic loading.By utilizing the rigid-body and connector functions of the software Abaqus,the multi-body structure of the reactor core is simplified as a mass-point system interlinked by spring-dashpot connectors.And reasonable schemes are used for determining various connector coefficients.Furthermore,a scripting program is also complied for the 3D parametric modeling.Numerical examples show that,the proposed method can not only produce the results which satisfy the engineering requirements,but also improve the computational efficiency more than 100 times.

Study on Time-Averaged Turbulent Conservation Equations under Supercritical Condition

ZENG Xiaokang, YAN Xiao, LI Yongliang, HUANG Yanping, XIAO Zejun

2012, 33(2): 56-61.

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The turbulent time-averaged conservation equations of supercritical fluid is obtained by the methods of Reynolds-averaging or mass-averaging based on the Navier-Stokes equations,to study how the transportation of mass and energy of supercritical fluid is effected by the turbulence of thermal property.The result shows that,the turbulent control equations under supercritical condition are similar to that under sub-critical condition,except that there are turbulence terms of thermal property in the equations of turbulence kinetic energy and turbulence eddy dissipation conservation equations.These turbulence terms of thermal property are not ignorable under the condition of supercritical pressure,which having the effect on the turbulence strength of fluid to change the transportation of mass and energy.

Numerical Analysis of Supercritical Flow Instability in Parallel Dual Channel

XIONG Ting, YAN Xiao, YU Jiyang, ZENG Xiaokang, XIAO Zejun

2012, 33(2): 62-65.

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Numerical analysis has been carried out for the supercritical flow instability in parallel dual channel by the time-domain approach.The mass.momentum and energy conservation equations are discre-tized using an implicit finite difference scheme.A computer code called SCIA is developed to calculate the flow characteristics in the parallel dual channel.Curves of pressure drop versus flow rate are obtained.Para-metric studies are carried out for the supercritical water in the parallel dual channel.Results show that for supercritical conditions,the static instability can hardly occur,and the parametric effects on flow instability are similar to those in two-phase flows.

Model Evaluation and Numerical Analysis of Supercritical Water Heat Transfer Deterioration in Circular Tubes

HUANG Zhigang, ZENG Xiaokang, LI Yongliang, YAN Xiao, XIAO Zejun

2012, 33(2): 66-70.

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This paper presents a numerical simulation of the heat transfer deterioration of supercritical water in circular tubes,and evaluates the validity and reliability of the existing CFD model under super-critical condition.The calculation indicates that when the heat transfer deterioration occurs at low mass flux condition,the velocity profile behaves M shaped in the radial direction,and at the place of maximum velocity,the turbulent kinetic energy decreases evidently.At high mass flux condition,the result shows that the varia-tion of thermal conductivity have great effect on the heat transfer.The mode evaluation indicates that SST mode can be used to calculate the heat transfer deterioration at high mass flux conditions.

Experimental Study on Heat Transfer Characteristics of Pebble-Bed Channels with Internal Heat Generation

MENG Xianke, SUN Zhongning, DENG Zhenguo, WANG Ge

2012, 33(2): 71-74.

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Aiming at the pebble bed channels with internal heat source for heating transfer,this paper adopts the electromagnetic induction heating method to separately heat the pebble-bed composed of 3 mm and 8 mm diameter oxidized stainless steel balls and to study the internal heat transfer characteristics.By comparing and analyzing the experimental data,the changing of power distribution and heat transfer coefficient with the heat flux density,particle diameter and Re number of working fluid in the pebble bed channels is obtained,and is fitted to get the dimensionless correlation criteria of the average heat transfer coefficient.The fitting results accord well with the experimental results,and the error is within 15%.

Experimental Study on Density Wave Oscillation in Parallel Channels

LIU Yanjun, SUN Yufa, YAN Xiao, XIAO Zejun

2012, 33(2): 75-77.

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Density wave oscillation phenomenon in parallel channels have been studied though the apparatus consisted of two uniformly heated boiling channel.Various situation of system pressure,mass velocity,inlet subcooing contribution to flow instability was distinguished.Moreover,dimensionless subcooling number ans phase change number boundary data was present.

Simulation of Fluid-Solid Conjugate Heat Transfer in Rectangular Channels

BI Shumao, LIU Changwen

2012, 33(2): 78-82,103.

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The fluid-to-solid conjugate heat transfer（CHT） in the rectangular channels with heated plates was simulated with CFX code in this paper,and the analysis of the sensitivity of the mesh to heat transfer was conducted,and a better mesh scale was obtained.Finally,the advantage of fluid-to-solid conjugate heat transfer simulation was analyzed by the comparison with the simulation of direct surface heat flux adding.The results show that by the fluid-to-solid conjugate heat transfer simulation,the weakness of channels can be studied more accurately,and thus to improve the performance of thermal engineering.

Numerical Simulation of Single-Phase Flow Resistance Characteristics in Two-Dimensional Porous Structure

WANG Xiong, ZHANG Zhen, YAN Xiao, XIAO Zejun

2012, 33(2): 83-87.

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A numerical simulation was carried out to study the resistance characteristics of single-phase isothermal flow in rectangular channels with two-dimensional regular packing of spherical particles using CFX 10.0.Simulated pressure drop of different turbulence models（Standard k-ε model,RNG k-ε model and SST model） were compared with the predicted values of Ergun’s equation.Particle packing style and particle diameter were considered as the important factors with effect on flow resistance in this paper.Besides,the pressure drop and drag coefficient variation trends were obtained when Reynolds number was in the range of 1.5~1497.

Development and Verification of Critical Leakage-Rate Analysis Program for Through-Wall Cracks

GAO Yongjun

2012, 33(2): 88-91.

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The calculation models and PC-Leakflow2 program,which give careful considerations to the effect of the crack-morphology parameters,are developed for evaluating the critical leakage-rate squirted from a circumferential through-wall crack（TWC）.The calculation flow diagrams and the solving method of PC-Leakflow2 program are described.The sensitivity analyses are conducted for each input parameter having an effect on the critical leakage-rate.PC-Leakflow2 program is validated by comparing the calculation results with the relevant critical leakage-rate experimental data given in the references.The calculation results pro-duced by PC-Leakflow2 program and the classic critical-flow models for the same benchmark problem indi-cate that the magnitude of the critical leakage-rate is strongly influenced by the crack-morphology parameters.The classic critical-flow models significantly over estimate the critical leakage-rate of a compact TWC.

CFD Simulations on Two-Phase Distribution in Rod Bundleswith Grid Spacers

LI Songyu, ZHANG Hong, JIANG Shengyao, YU Jiyang

2012, 33(2): 92-96.

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Considering the bubble coalescence and break-up,the CFD simulations for air/water two-phase flow in 3×3 rod bundles with grid spacers have been performed with MUSIG model.The simulation is sensitive with the bubble diameter size but not with the inlet void fraction.The small diameter bubbles are the main effect of void fraction distribution nearby the downstream of the space grid,while the large diameter bubbles are main effect of void fraction distribution at the farther downstream of the space grid.Considering the effect of inlet air-water flow quality,geometry and pressure on bubble max diameter,this paper gives a relation for simulating the bubble with maximum diameter based on which is dealt with numerical simulation for rod bundles with grid spacers is set,and the advice of simulation method and model setting is given.The calculation results show that the shape and peak of void fraction distribution accord well with the experiment,and this simulation method can predict rationally the distribution of two phase flow in complicated channels.

Effect of Pumping Chamber Outlet Contraction Angle on Hydraulic Performance of Main Nuclear Reactor Pump

ZHU Rongsheng, LI Xiaolong, YUAN Shouqi, FU Qiang, WANG Xiuli

2012, 33(2): 97-103.

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An RCP（reactor coolant pump） impeller and diffuser are designed to meet the hydraulic performance needs of the nuclear reactor coolant pump in a domestic 1000MW nuclear power plant.In order to study the effect of the pumping chamber outlet contraction angle,13 kinds of are designed and Pro/E is utilized for three-dimensional design,and CFD code Fluent is utilized for numerical simulation.Finally,the internal velocity vector and streamline of the RCP are obtained.It is revealed that the contraction angle has a significant effect on the connection area between pumping chamber and outlet.As is between 12° and 16°,and the efficiency of the RCP is above 70%.When is 15°,the efficiency reaches to the maximum 74.2%.When is 15° and other parameters unchanged,the reverse flow region of the impeller inlet and diffuser outlet becomes larger with the decrease of the flow rates.When the flow increases,the reverse region approaches closer to the impeller inlet.Reverse flow is the main cause of the pressure fluctuation of the connection area between pumping chamber and outlet,and the farther away the design point,the more serious the pressure fluctuation.

Research on Model of Additional Forces of Ocean Conditions in One-Dimensional Coolant Channel

QIAN Libo, TIAN Wenxi, QIU Suizheng, SU Guanghui, LI Yong, HUANG Yanping, YAN Xiao

2012, 33(2): 104-109.

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The effect of different ocean conditions on coolant flow can come down to the differences of additional forces in the momentum equations,thus ocean conditions can be considered by adding the additional forces caused by them to the momentum equations.The model of additional forces of 6 types of typical and relevant coupled ocean conditions is obtained based on the basic momentum equation in the non-inertial reference frame and the one-dimensional coolant channel.

Effects of Channel Direction and Movements on Boiling Flow and Heat Transfer

REN Zhihao, KUANG Bo, NI Chao, QIN Shengjie, ZHANG Zhen, HUANG Yanping, YAN Xiao

2012, 33(2): 110-115.

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Based on the coupling of two-fluid model and wall dynamics model,and the comprehensive comparison and selection of specific correlation combination,along with related verifications,a transient simulation code on boiling flow and heat transfer analysis for the rectangular narrow gap channel is developed.Through numerical experiment method,effects of such factors as location,direction and movements of the channel on the boiling flow and heat transfer within the channels between heated wall are studied in this paper.The prediction results about effects of the above mentioned factors on boiling heat transfer coefficient,pressure drop,element temperature and some transient flow and heat transfer behaviors are expected to provide beneficial guidance on the test,design and application of related core channels.

Calculation of Reactor Kinetic Parameters with Monte Carlo Method

WANG Guanbo, LIU Hangang, WANG Kan, LIU Yongkang, ZENG Herong, YANG Xin

2012, 33(2): 116-122.

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Basic conceptions of kinetic parameters,including effective delayed neutron fraction（β_eff）,effective neutron generation time（Λ_eff） and α eigenvalue,and Monte Carlo calculation methods for these values are systematically introduced in this paper.β_eff is obtained with a "Prompt Method".Perturbation method is chosen to obtain Λ_eff.And then α eigenvalue is obtained by two ways,（i） prompt neutron density attenuation,in other words "direct simulation of time evolvement",（ii） indirect method using the result of k_p and neutron generation time.Linear fitting is used to get the critical αc eigenvalues which match well with experimental ones.And uncertainties of kinetic parameters with different methods using Monte Carlo method are also analyzed.

Dose Assessment Method for Control Room Habitability in Accident Condition in Nuclear Power Plants

YANG Dong, TANG Shaohua, WANG Jianhua

2012, 33(2): 123-126.

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Based on the NRC technical requirements on NPP control room habitability assessment,and considering the characteristics of the improved second generation NPPs in China,this paper developed a complete dose assessment model for control room habitability.Contrasting to the existing model in China,this model is applicable for DBA and severity accident,and the short term atmospheric diffusion factor can be calculated using the combined wake mode.By considering the zoning of habitable area and the design characteristics of the ventilation system,the effects of un-filtrated air leakage from the building and the ventilation system on the assessment calculation can be considered.

Study on Method of Dividing Plume Emergency Planning Zone in Nuclear Power Plants

HUANG Ting, QU Jingyuan, TONG Jiejuan, CAO Jianzhu

2012, 33(2): 127-131.

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Considering the safety features of different types of reactors,different methods of dividing plume emergency planning zone（PEPZ） were compared and analyzed,and then systematically classified ac-cording to the reactor types.The applicable methods of dividing PEPZ for different reactor types were pro-posed.Finally,the methods were preliminary applied taking the High-Temperature gas-cooled Reactor-Pebble bed Module（HTR-PM） as an example.The preliminary study results show that,the site boundary of HTR-PM meet the criteria of dividing PEPZ,and compared with the large light water reactors,its PEPZ can be signifi-cantly decreased.

Analysis on Damage Cause of Belt Eyes for Bypass Feedwater Isolation Valves of Daya Bay and Ling’ao NPPs

CHE Yinhui, GUAN Jianjun, LV Qunxian, YANG Xiaochuan

2012, 33(2): 132-134.

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When all of bypass feedwater isolation valves of Daya Bay and Ling’ao NPPs were inspected under disassembled condition,it was found that the belt eyes were damaged in various degrees.The analysis on macro appearance,chemical composition,metallographic,Scanning Electron Microscope and fluid mechanics simulation were carried out on the damaged belt eyes.The results show that the flow rate of belt eye is well above the manufacturer’s recommendation so that flow accelerated corrosion and cavitation erosion occur on the belt eyes.According to the damage causes of the belt eyes,corresponding corrective actions are proposed.

Measurement and Analysis of Nuclide Lixiviate Rate of Radwaste Cement Solidification Sample

KONG Jingsong, GUO Weiqun

2012, 33(2): 135-138.

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Based on the experiment of cement solidification thermal formula for radioactive spent colophony,residua and evaporation raffinate,the nuclide lixiviate rate of radwaste cement solidification samples are measured by HPGe-γ instrument,low background α and β measurement apparatus,and the nuclide lixiviate rate of radwaste cement solidification samples of different source terms are analyzed.It validates the accuracy and the reliability of the formula for the related cement solidification samples.The result shows that the nuclide lixiviate rate of ⁶⁰Co,¹³⁷Cs and total β in various cement solidification samples of colophony,residua and evaporation raffinate decrease acutely in front phase.The nuclide lixiviate rate changes steadily along with the time goes on.The value of nuclide lixiviate rate satisfies the requirement of GB 14569.1-93.

Quantitative Analysis of Fit-up Accuracy for Field Narrow Gap Orbital TIG Welding of Primary Piping in PWR Nuclear Power Plants

GUO Lifeng, WANG Quan, DONG An

2012, 33(2): 139-144.

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Field Narrow Gap Orbital TIG（NGOT） welding of the primary piping requires much more strict fit-up accuracy.To satisfy this requirement,a 3-D geometric computer model was developed to conduct the quantitative analysis of the relationship between fit-up accuracy and variables in the manufacture and in-stallation process.The essential variables were identified and recommendations were given for the construc-tion program based on the analysis results.

2012 Vol. 33, No. 2