核动力工程

Discussion of LWR-RPV Lifetime and Irradiation Embrittlement Effect Prediction Formula in NRC-RG1.99-2

ZHANG Jing-cai

2009, 30(6): 1-7.

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This paper focuses on the LWR-RPV lifetime and discusses the application limitation and non-conservative for the irradiation embrittlement predictive formula in NRC-RG1.99-2.It is suggested that a new irradiation embrittlement predictive formula shall be used for the newly built LWR-RPV,or the formula in NRC-RG1.99-2 shall be revised.

Effect of Hydrogen/Electron Dual-Beam Irradiation on Stability of Dispersed Oxide Particles of 12Cr-ODS Steel

HU Ben-fu, GUO Li-na, JIA Cheng-chang, YANG Zhan-bing, H. Kinoshita, H. Takahashi, S. Watanabe

2009, 30(6): 8-10,14.

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The effects of hydrogen/electron dual-beam irradiation on the stability of oxide particles of a new 12Cr-ODS ferrite steel made by chemical socking method was studied in this paper.The observation of the microstructure of oxide particles under different irradiation doses show that,before irradiation and after an irradiation dose to 15dpa,the size of 10-20nm oxide particles have little change,the small number density voids have no effect on the stability of the oxide particles;as temperatures increased to 823 K,the phase inter-face of the bigger size dispersed oxide become irregular,while the size of the oxide particles remain stable.The results show that,the size of the dispersed oxide is stable,no solubility process was observed.

Granularity Control of U-10wt%Mo Powder Prepared by HMD Method

CHEN Jian-gang, YIN Chang-geng, SUN Zhang-long, PANG Xiao-xuan, LIU Yun-ming, SUN Xu-dong, YANG Hong-yan, LI Chuan-feng

2009, 30(6): 11-14.

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The granularity control of U-10wt%Mo alloy powder prepared by hydriding-milling-dehydriding（HMD） method is introduced in this paper.U-Mo alloy is annealed for 4 h,10 h and 24 h at 950 ℃.Then U-Mo alloy powder is prepared through the process of γ→α phase transition,hydrid-ing-milling-dehydriding and α→γ phase transition.Analysis results indicates that the U-Mo grain grows slowly at 950 ℃,and the grain size could be controlled in the range of 40~100 μm by adjusting time.The γ-phase transition is strongly depended on the grain size,and when grain is big,γ→α phase transition is difficult.The powder size is related tightly with the grain size in the initial γ-phase alloy,and when γ-phase grain is big,the mass percent of coarse powder is high.

Development of an In-Core Fuel Management Program for Solution Reactors

LI Yun-zhao, WU Hong-chun, CAO Liang-zhi, PENG Si-tao, LU Hao-liang, SONG Xiao-ming, YAO Dong

2009, 30(6): 15-18,23.

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Solution reactor,as a new type of medical isotopes production reactor,is with many special features,such as flowing aqueous fissile solution,unstructured geometry,strong anisotropic scattering,and isotopes distillation.They all raise serious challenges for the fuel management calculation of solution reactors.An in-core fuel management calculation program package for solution reactors,called FMSR,is developed based on the DNTR code,a three-dimensional discrete ordinate nodal transport calculation code in triangular meshes.All results calculated by FMSR,including the distribution of power and void and cycle length and coefficients of reactivity,show that the program package can be used for the in-core fuel management calcula-tion of solution reactors as a trial.

Measurement and Validation of Coefficient of Thermal Expansion of Graphite IG-110 under Compressive Stress

ZHOU Xiang-wen, WANG Hong-tao, YU Su-yuan

2009, 30(6): 19-23.

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Coefficient of thermal expansion（CTE） of nuclear graphite IG-110 under compressive stresses was measured with the strain gauge method,and the corresponding effects of stresses on the CTE of IG-110 were analyzed.Results indicate that the strain gauge method is feasible and reliable in the CTE measurement of IG-110.Compressive stresses have significant effects on the CTE of graphite IG-110.Compared with those of the unloaded specimens,CTE parallel to the loading direction of specimens increases from 3.71×10^-6 K^-1 to 4.20×10^-6 K^-1,4.41×10^-6 K^-1 and 4.78×10^-6 K^-1 for compressive stresses of 20,30,40 MPa which increases by about 13.2%,18.9% and 28.8%,respectively.Meanwhile,CTE perpendicular to the loading direction de-creases from 4.03×10^-6 K^-1 to 3.80×10^-6 K^-1,3.79×10^-6 K^-1 and 3.75×10^-6 K^-1 which decreases by around 5.7%,6.0% and 6.9%,respectively.CTE changes of nuclear graphite under stresses are probably due to the opening or closure of micro-cracks induced by stress in graphite.

Applicability of Void Fraction Models in Rod Bundle at High Quality Conditions

CENG Jian-li, LIU Xiao-jing, CHENG Xu

2009, 30(6): 24-27,37.

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Void fraction model is of great importance to the sub-channel analysis.However,the applica-bility of the void fraction models in the sub-channel codes COBRA under high void fraction conditions is not sufficiently validated.Based on a literature review,four void fraction models are selected and applied to the COBRA code to calculate the thermal hydraulic parameters in rod bundles.Comparing to the experimental data obtained in a 4×4 rod bundle using water as coolant,the selected void fraction models are assessed by using relative enthalpy rise and relative mass flux in various sub-channels.It was found that the calculated sub-channel parameters with the Dix model and the slip model（with a slip ratio of 1.5） give the best agree-ment with the experiment data.

Study on Scaling Law of PWR Natural Circulation with Motion Condition

LU Dong-hua, XIAO Ze-jun, CHEN Bing-de

2009, 30(6): 28-37.

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For some nuclear reactors installed on automobiles,boats or deep sea vehicles,it is an impor-tant way to investigate their system safety by performing natural circulation experiments under motion condi-tion.This paper studied the natural circulation on moving plants based on work of static natural circulation scaling method.With rigid motion theory,acceleration at each point was obtained on primary system and introduced to momentum equation.Thus a set of motion similar criteria were obtained.Furthermore,equal and unequal height simulation were analyzed.As to the unequal one,non isochronous simulation was needed for displacement and angular acceleration.

Development of RELAP5 Coupling Interface

LIU Yu, ZHANG Hong

2009, 30(6): 38-40,45.

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The program structure of RELAP5 code was studied in this paper,and a coupling interface model including parameters output,input and time step control was developed.This RELAP5 coupling inter-face was realized using Parallel Virtual Machine（PVM） software.Test results of two type problems show that the development of coupling interface is successful.It can be used as the basis for coupling with other codes.

Experimental and Numerical Studies on Mixed Convection in Vertical Rectangular Channels

QIU Zhi-fang, XIE Zheng-rui, GU Han-yang, CHENG Xu

2009, 30(6): 41-45.

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Mixed convection in rectangular channels is frequently encountered in engineering applications.In spite of extensive studies,investigations on mixed convection coupled with thermal radiation are relatively scarce.The present authors carried out the experimental and numerical studies on the mixed convection coupled with thermal radiation in a vertically oriented rectangular channel.The results show that for upward flow in a vertical channel,buoyancy shows a strong effect and leads to a significant decrease（impairment）in heat transfer in the range of small buoyancy number.With increasing buoyancy number,the heat transfer coefficient,compared to that at forced convection conditions,recovers again.This evidence agrees well with previous studies in the open literature.Furthermore,it is concluded that thermal radiation plays an important role in the process of heat transfer,especially in the parameter range,where heat transfer impairment occurs.Numerical simulation using CFD and low Reynolds turbulence models shows reasonable agreement with the experimental data at low Buoyancy number conditions.The deviation between the numerical results and experimental data becomes larger at high Buoyancy number conditions.

Application of Degree of Similarity in Choice of Correlations for Supercritical Water Reactor

HU Yu, ZHOU Tao

2009, 30(6): 46-48,52.

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Base on the correlations of supercritical water reactor,using the degree of similarity,which is included in Fuzzy Mathematics,a new calculation model for calculating the degree of similarity between actual status and the empirical correlations is designed.By this model,the actual status is compared with the empirical correlations,and the best correlation for actual status is obtained.It is indicated that the degree of similarity can be used in the choosing of the best correlations for the problem about heat transfer of supercritical water-cooled reactor,based on the known correlations,resulting in the results with higher accuracy.

Numerical Analysis of Control Valve Open Ratio Effect on Letdown Flow

WANG Zhi-gang, LI Li-juan, LI Jun, WANG Xiao-jiang

2009, 30(6): 49-52.

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The internal flow and heat transfer in the letdown pipes of Chemical and Volume Control System（RCV） are investigated with numerical simulation,and Flowmaster V7 is employed to achieve these objects.The effect of control valve RCV013VP open ratio on the letdown flowrate and other physical variables is numerically investigated.The results show that the letdown flowrate is sensible when RCV013VP open ratio is less than 60%,while the letdown flowrate seems to be independent with the valve open ratio when it is more than 60%.In the normal operation,even if the RCV013VP is fully open,flashing will not occur in the letdown pipes.As the control valve opens more,coolant pressure in the letdown pipes will be closer to the coolant saturation pressure at the corresponding letdown temperature.

Development of Ocean-Condition Code Based on RELAP5

TAN Zhang-lu, ZHANG Hong, ZHAO Hua

2009, 30(6): 53-56,62.

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Mathematical models of ocean conditions have been studied.By modifying the control equa-tions,an ocean condition available system analysis code named RELAP5/MC is developed from RELAP5,which is an advanced and independent node programming code.Calculation of the natural circulation charac-teristics of a simple two loop system under ocean conditions has been carried out with RELAP5/MC.The analysis shows that all the results can be reasonably explained and the code development is successful at this stage.

Fusion Identification Method for Gas-Liquid Two-Phase Flow Regime Based on Recurrence Quantification Characteristics

SUN Bin, LI Chao, ZHOU Yun-long

2009, 30(6): 57-62.

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To increase further the accuracy of flow regime and considering the non-stationary charac-teristics of differential pressure fluctuation signals of gas-liquid two-phase flow,the flow regime identifica-tion method based on recurrence quantification analysis（RQA） and multi-sensor data fusion techniques is put forward.First of all,the recurrence quantification analysis method is used to extract the nonlinear feature pa-rameters of the differential pressure fluctuation signals of gas-liquid two-phase flow,and data fusion of fea-ture layer is conducted by QRA feature parameters of differential pressure signals of three pressure measure intervals,and composes the fusion feature vectors.The fused characteristic vector are input into the support vector machine for identify flow regime.The identification results for four typical flow regimes of air-water two-phase flow in horizontal pipe has shown that the reliability of the identification result is improved evi-dently.

Upward Heat Transfer Characteristics of Supercritical Pressure Water in Square Annular Channel

SHI Xiao-bao, WANG Hai-jun, LUO Yu-shan, CHEN Ting-kuan, LI Hong-zhi

2009, 30(6): 63-66,75.

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Heat transfer in square annular upward flow channel was studied on the supercritical water heat transfer facility at Xi’an Jiaotong University.Experimental pressure is range of 23~25 MPa,mass ve-locities of 500~1 200 kg/（m²·s）,heat fluxes of 200~800 kW/ m²,and bulk inlet temperatures of 300~400 ℃.Experiment results showed that at high mass velocity and relatively low heat flux,the heat transfer in square annular geometry with helical wire-wrapped spacer would be enhanced,whereas at low mass velocity and relatively high mass flux,the heat transfer deterioration would occur.Comparison of experiment data showed that at lower supercritical pressure,heat transfer was enhanced more impressively but the deterioration was more likely to occur while relatively higher supercritical pressure means better security.

Analogue Simulation for Local Damage of Drain Pipe

DAI Zhen, HAO Xiao-jun, NIU Xiao-guang, JING Shang-qian

2009, 30(6): 67-69,90.

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For the leakage of variable diameter drain pipe caused by local thinned area,the synergism of cavitation and erosion is regarded as the main factor.In order to obtain the distribution of damage,CFD code was used.The calculated result shows that static pressure reaches its minimum at the small-end of conical pipe behind the valve and is lower than the vaporization pressure,which will cause the cavitation,and maximum of shear stress appears at the same position,which accelerates the erosion effect of fluid.Furthermore,corresponding proposals are put forward to prevent the conical drain pipe from local damage.

Analysis of Continuously Maintained Complex Redundancy System with CCF Based on GO-FLOW Methodology

SHANG Yan-long, CHEN Li-sheng, CAI Qi, ZHAO Xin-wen

2009, 30(6): 70-75.

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By improving the function of GO-FLOW operators,and referring to the quantificational cal-culation model to solve the Common Cause Failure（CCF） in the continuously maintained system,a quantita-tive analysis method was developed to analyze the continuously maintained complex redundancy system reli-ability with CCF by the GO-FLOW in probability risk assessment,and a practical calculation example was presented.It shows that the GO-FLOW algorithm can effectively analyze the reliability of the complex system which contains many sorts of cause leading to CCF and multiple Common Cause Failure Component Groups（CCCGs）,and which can intuitively reflects the changing trend of failure probability in the operation process of the system.Compared with GO methodology,the GO-FLOW can effectively analyze the multi-state and complex system in quantificational calculation of the CCF.

Application of Large Event Tree/Small Fault Tree Approach in Evaluation of MNPP Feedwater Lines Large Break Accident

XIN Shi-bao, XIANG Qing-an, ZHANG Zhi-jian

2009, 30(6): 76-79.

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The principle of large event tree/small fault tree approach,the gist and rule for small event classification,and the establishing rule and modularization of large event tree are introduced.The dominant contributors to the core damage and the weakness of the system were identified through studying the Probability Safety Assessment（PSA） by large event tree/small fault tree approach for the feedwater lines large break accident of MNPP in full power condition.The result of application indicates that the approach is with the advantage of directly representing the relativity between the support system and front system and estimating the importance of the support system.

Quantitative Analysis of Error Mode,Error Effect and Criticality

LI Peng-cheng, ZHANG Li, XIAO Dong-sheng, CHEN Guo-hua

2009, 30(6): 80-85.

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The quantitative method of human error mode,effect and criticality is developed in order to reach the ultimate goal of Probabilistic Safety Assessment.The criticality identification matrix of human error mode and task is built to identify the critical human error mode and task and the critical organizational root causes on the basis of the identification of human error probability,error effect probability and the criticality index of error effect..Therefore,this will be beneficial to take targeted measures to reduce and prevent the occurrence of critical human error mode and task.Finally,the application of the technique is explained through the application example.

Turbine Faults Diagnosis Based on Gaussian Mixture Models

LUO Mian-hui, LIANG Ping

2009, 30(6): 86-90.

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The Gaussian Mixture Models and the wavelet packet analysis are used to the turbine vibration faults diagnosis.De-compound firstly the vibration faults signal and delete the disturbed component.Then,take the frequency segments which contain the fault characteristics as the fault characteristics vector.To set up the Gaussian Mixture Models with the vectors,and identify the different faults with the built model.The experiment data measured in Benlty experiment platform is adopted to set up the model and identify the faults.In the calculation results,when the modulus equal to twelve,the precision for the faults diagnosis by the Gaussian Mixture Models is approximately 80%～90%.It indicates that the turbine vibration fault can be diagnosed effectively by the Gaussian Mixture Models and the wavelet packet analysis.

Development of Internal Vibration Monitoring System for NPP Based on Neutron Noise Technique

LIU Cai-xue, ZHENG Wu-yuan, WANG Cheng-yuan, HU Jian-rong, JIAN Jie, LI Xiang

2009, 30(6): 91-94,103.

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The vibration monitoring system for internal structures developed for Qinshan Nuclear Power Phase II Extension Project is able to monitor the vibration of reactor pressure vessel and internal structures,which comprises four acceleration and eight neutron noise channels.Several modern techniques are applied in the system,for instance,FPGA are adopted in signal preprocessing;PXI bus technology are applied for the synchronization processing between channels and modules;Original data is stored in a standard form and an open entry is supplied;The signal analysis tools include time field,auto-power spectrum density,cross-power spectrum,coherence and phase are provided for the vibration analysis.The system can monitor the vibration of pressure vessel,core barrel and fuel assemblies,and etc.

Stability Analysis of OTSG Based on Augmented Vector Bilinear Model

TAI Yun, HOU Su-xia, ZHAO Fu-yu

2009, 30(6): 95-98,103.

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In order to achieve the more precise system characteristics,this paper builds the model of the heat exchange process of OTSG based on the augmented vector bilinear system according to the lumped Lyapunov theory in the light of the steadily parameters in some rating condition.The result shows that that system is vulnerable with the pressure loss coefficient dropping down when the power is fixed,and with the increasing of the power,the system is more steady because of the length of the preheated region getting longer

Digital Design and Reliability Analysis for Qinshan Phase-I Reactor Power Control System

LIU Chong, ZHOU Jian-liang, YAO Qiu-guo, TAN Ping, ZHAO Da-wei

2009, 30(6): 99-103.

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A novel control strategy based on the redundancies of CPU,power supply and ControlNet field-bus is proposed to solve the problems of equipment aging,maintenance and reliability of Qinshan Phase-I 300 MW reactor power analog instrumentation and control（I＆C） system.Digital design based on PLC control technology is used to replace its rod control and position indication so that the limitations of being unable to adjust the system parameters online and poor anti-interference capability can be avoided and the system communication,central monitoring,maintainability,reliability and security can be improved.The modular program design can strengthen the readability and practicability,shorten the scanning time and speed the response.The feasibility and rationality of the design have been proved in a practical reactor operation.Finally,the author briefly introduces some feasible ways to enhance the reliability of the reactor digital control system.

Engineering Design for Radwaste Repository in Urban

RONG Feng, LI Jin-yan, WANG Jin-ming

2009, 30(6): 104-107.

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Urban radwaste repositories are territorial repositories for the storing of radwaste only,which is very important for the safe management of the low-level radwaste produced in the nuclear technology applications.Baced on the practice of the engineering design of urban radwaste repositories in china,the technique scheme for the reposition of radwaste from urban area,and the gists for the engineering design have also been discussed in this paper.

Study on Opportunity Maintenance Strategy of Equipment outside Nuclear Island Based on Operational Availability

CHEN Yan-qiao, JIN Jia-shan, HUANG Zheng

2009, 30(6): 108-111.

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Considering the characteristics of that the failure downtime of nuclear power plant will lead great economic loss and that the partial equipment outside the nuclear island can be maintained parallelly,the opportunity maintenance strategy for equipment outside the nuclear island is studied.An opportunity maintenance control strategy is put forward based on the optimal maintenance interval of equipment itself.The simulation algorithm for solving optimal maintenance interval and opportunity maintenance coefficient is offered using Monte Carlo simulation method with maximal operational availability during given time interval.The validity of the opportunity maintenance strategy for advancing system operational availability is proved by an example.

Calculation and Analysis System for Ultrasonic Testing in Nuclear Power Plant

ZHANG Jun, DING Hui, WANG Zhong-ya, ZHANG Yi-cheng

2009, 30(6): 112-116.

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The theoretical model of acoustic field calculation and interaction between field and defect is proposed based on Rayleigh Integration,Kirchhoff approximation,Geometrical theory of diffraction and Born approximation theory,and then the calculation and analysis system of ultrasonic testing（UT-CAS） is devel-oped for the inspection of the key components in nuclear power plants.The application of UT-CAS is intro-duced by the modeling of the safe end bi-metallic weld inspection.UT-CAS can quickly and accurately model various inspection cases,and is helpful for the data analysis,performance demonstration and NDT training.

Index

2009, 30(6): 117-128.

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2009 Vol. 30, No. 6