核动力工程

Two-Dimensional Matrix Characteristics Method Based on Krylov Subspace and Domain Decomposition Theories

ZHANG Hong-bo, WU Hong-chun, CAO Liang-zhi, ZHENG You-qi, XIA Bang-yang

2013, 34(4): 1-6,15.

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Abstract:
A matrix characteristics method is proposed based on Krylov subspace and domain decomposition theories to improve the efficiency of the conventional method of characteristics（MOC）.The new numerical method,with the form of linear algebraic equation systems,is derived from the MOC basic equations and solved efficiently by the generalized minimal residual（GMRES） method.The spatial non-overlapping domain decomposition method with multiprocessing parallel technology is then adopted to reduce the computational burden for large-scale problems.By inheriting the geometrical treatment manners of the conventional MOC solver AutoMOC,the theories mentioned above are implemented.Numerical results demonstrate that the matrix characteristics method with satisfactory accuracy is more efficient than the conventional MOC,and has good flexibility in complex geometry and strong scattering problems.

Study on Acceleration of Three Dimensional Characteristics Method

ZHANG Zhi-zhu, LI Qing, WANG Kan

2013, 34(4): 7-11.

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As the reactor physics computation develops,the neutron transport equation would be solved on three dimensional complex geometry accurately,where the MOC can meet all these needs.However,the slow convergence and long computation time limit its application.Both numerical acceleration method and parallel computing technique are used in this paper to accelerate the MOC.Two-level GCMFD and angular parallelization are implemented into the three dimensional characteristics method code TCM to carry out test calculations in some benchmark problems.The results show a good performance on reducing the number of iterations and speeding up the code while keeping the accuracy of the computation.

Validation of Accelerator Driven Subcritical Reactors Utilizing MCNP Code

HU Wen-chao, OUYANG Xiao-ping, LIU Bin, WANG Kai, HUANG Li-ming

2013, 34(4): 12-15.

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In this paper,some characteristics of the ADS subcritical reactor core is described using the Monte Carlo code（MCNP）.The k_eff value,neutron energy spectrum and neutron flux of a ADS system are obtained by the MCNP code under certain ADS core size as the ADS target and coolant are lead,lead-bismuth alloy,bismuth and mercury respectively.The data and the ADS system parameters obtained from the MCNP simulation calculation are compared and analyzed.The results show that the lead-bismuth alloy is the best material for ADS target and coolant among all the materials tested.

CATHARE Simulation on Coupled Neutronics/Thermal-Hydraulics of Molten Salt Reactor（MSR）

PENG Chuan-xin, YAN Xiao, PENG Jing-feng, CENG Xiao-kang, HUANG Yan-ping, XIAO Ze-jun

2013, 34(4): 16-19,89.

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According to the characteristics of fuel salt and moderator in Molten Salt Reactor,the PWR thermal-hydraulic code CATHARE is modified,which is applied to study the behaviour of a single-channel of the MSR core.The calculation results show that CATHARE can predict the coupling of thermal-hydraulic and neutronics in steady-state conditions and under several transients（i.e.,reactivity variations and fuel mass flow rate variations）.

ERVC Effectiveness Analysis for Three-Layer Configuration Molten Pool

CAO Ke-mei, XU Yi-quan, SHI Guo-bao, CAI Jian-ping

2013, 34(4): 20-22,94.

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In-vessel retention of molten core debris（IVR） through the External Reactor Vessel Cooling（ERVC） is an important severe accident management feature employed in the 300MW PWR plant.In the previous IVR analysis,it is usually assumed that there is a two-layer configuration（metal-over oxide） of molten core material in the RPV lower head,however,an alternate three-layer molten pool configuration with a dense bottom metal layer below the oxide layer can be formed due to molten material interactions in the lower plenum,and it may bring a greater threat to the RPV integrity.Based on the established model,IVR analysis is performed for the assumed three-layer molten pool configuration for 300MW PWR plant,and the results show that the dense bottom metal layer will not threaten the RPV integrity,but the thin top metal layer has a small margin-to-failure,which may threaten the RPV integrity.

Effect of Variable Viscosity on Flow Resistance Characteristics of Porous Channel with Internal Heat Source

ZHANG Xiao-ning, SUN Zhong-ning, MENG Xian-ke, XU Guang-zhan

2013, 34(4): 23-26.

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The effect of variable viscosity on flow resistance characteristics of porous media with internal heat source was investigated.The experiments were performed on volumetrically heated porous media thermo-hydraulic test loop.Flow resistance characteristics of porous media are affected as viscosity of fluid is changed due to the changed temperature.The effect of variable viscosity on pressure-drop is prominent at high Reynolds numbers and it becomes weaker as Reynolds number increases.The difference of nondimensional pressure-drop curves between heating and adiabatic conditions is obvious at low inlet temperature.The difference becomes less significant as inlet temperature increases and all the curves are merged.New correction factors ξμ and ξCof Hazen-Dupuit-Darcy（HDD）model are presented and the relative error of pressure-drop factors between calculated values and experimental data is in the range of ±11.8%.

Study on Second-Order Scheme for One-Dimensional Two-Fluid Model of Reactor

ZHANG Xiao-ying, DING Fei, CHEN Jia-yue

2013, 34(4): 27-32.

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At present,the numerical solution of one-dimensional two-fluid model is only first order.Safety design of advanced reactor depends on higher-ordered numerical scheme and code.This work aims at the investigation of the second-ordered scheme for the one-dimensional two-fluid model,to apply the second scheme for improving one first-order test code TFIT to second ordered.Flux-limiter scheme is used for the convection term,the surface tension term is adopted to make the numerical solution stable.The classical water wave problem-water faucet problem is used as the benchmark to test the second-ordered scheme.The numerical solutions of second-ordered and first-ordered scheme are compared with analytical solutions,and the comparison shows that the second-ordered solutions tend to analytical solutions better,catch the void wave of the water faucet problem well,and keep to the same stability of first-ordered code.

Development of a New Model to Predict Heat Release in Vicinity of Quench Front in Tight Lattice

WU Dan, YU Hong-xing, YU Jun-chong, YU Ji-yang

2013, 34(4): 33-37.

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The flow and heat transfer characteristics in the vicinity of the quench front where quenching takes place are very complex.It is of great importance to predict the heat release in this region because that the vapor generation will influence the water distribution in the core.For the reflooding in a tight lattice,experimental results revealed that the cladding temperature drops rapidly when quench takes place,while the cladding temperature history curve was not well predicted using the existing transition boiling correlations.In this study,a new model named "transient thin liquid meniscus evaporation" is proposed to predict the heat release in the vicinity of the quench front.Through comparison with the experimental results,it is found that this new model can better predict the cladding temperature variation in the vicinity of the quench front.

LES Calculations for Pressure and Velocity Transient Characteristics on Spacer Grids Outer Ribbons

LU Chuan, LU Qing, ZHANG Hong, LU Jian-chao, JIAO Yong-jun

2013, 34(4): 38-42.

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Pressure and velocity transient characteristics was analyzed by CFD based on RANS and LES.Both calculations showed the macroscopical results were similar with each other.The transient characteristics can not be obtained by RANS calculations,while LES calculations could show transient pressure and velocities effectively.Different results could be found in detail between RANS and LES.LES calculations also gave the pressure fluctuations.Frequency spectrum analyzing showed that in different area the pressure fluctuations characteristics were different,which could be used for mechanics design.

Numerical Study on Single Phase Flow Resistance Characteristics in Randomly Packed Channel with Spheres

ZHANG Nan, SUN Zhong-ning

2013, 34(4): 43-46.

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The randomly packed bed with spheres was generated by discrete element method（DEM）.Single phase flow through the packed bed was simulated and validated.For contact issue of the particle to particle and particle to wall in the meshing,a bridge method was presented,which is not only used to generate high-quality grid,and the overall number of grid are reduced significantly.Simulations of the radial porosity distribution,average porosity and flow resistance are agreed with the classic correlations,and the validated models can reflect the wall boundary effect on the flow resistance.

Pressure Fluctuation Characteristics of Flow Field of Mixed Flow Nuclear Primary Pump

WANG Chun-lin, YANG Xiao-yong, LI Zhang-jun, JIA Fei, ZHAO Bin-juan

2013, 34(4): 47-52.

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In order to research the pressure fluctuation characteristics of flow field of mixed flow nuclear primary pump,this study used the technique of ANSYS-Workbench and CFX fluid solid heat coupling to do numerical simulation analysis for model pump.According to the situation of pressure fluctuation of time domain and frequency domain,the main cause of pressure fluctuation was discussed.For different flow,the pressure fluctuations were compared.This study shows it is feasible that large eddy simulation method is used for the research of pressure fluctuation.The pressure fluctuation amplitudes of four sections are increasing from wheel hub to wheel rim.The pressure fluctuation of inlet and outlet of impeller depends on the rotational frequency of impeller.Along with the fluid flowing away from the impeller,the effect of the impeller on the fluid pressure fluctuation weakens gradually.Comparing the different results of three flow conditions,the pressure fluctuation in design condition flow is superior to the others.

Turbulent Heat Transfer Characteristics of Liquid Sodium Flow in An Annular Tube

WANG Mei, WU Ying-wei, TIAN Wen-xi, SU Guang-hui, QIU Sui-zheng

2013, 34(4): 53-57.

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The high Re number k-ε model and boundary condition of wall function method were applied to compute the turbulent heat transfer characteristics of liquid sodium flow in an annular tube.The numerical results are in good agreement with some experimental results in open literatures.Meanwhile,the turbulent heat transfer characteristics which is influenced by factors of the turbulence,heat condition and geometry size were studied.The analysis results indicate that: the influence of the turbulence was mainly reflected in the forepart of the tube.As the molecule diffusion effect played a more important role gradually in the middle and posterior part,the heat transfer difference between different turbulence flows decreased gradually along the flow direction.The factors of initial temperature and heat flux have little effect on Nu number.The turbulent heat transfer increases as the gap size of the annular tube increases,and with the same gap size,as the internal diameter and external diameter increase,the heat transfer coefficient changes very little.

Critical Heat Flux Prediction Model for Low Quality Flow Boiling

PAN Jie, YANG Dong, XIAO Rong-ge, DENG Zhian

2013, 34(4): 58-63.

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Based on the near wall bubble crowding mode,aimed at the two-phase flow boiling heat transfer at high pressure and low flow rate conditions,a critical heat flux prediction model for low vapor quality region was developed in this paper.The limiting transverse mass flux crossing the interface of the bubbly layer and core was determined from a momentum balance in the model.A formula for detached bubble diameter considering buoyancy and some existing correlations for bubble detachment point,turbulent velocity profile and void fraction were applied in the model,and the critical void fraction of wall bubbly layer were presented based on the experimental data.A good agreement is achieved between the results and experimental data,which implies that the CHF model is accurate at high pressure and low flow rate.

Heat Transfer Characteristics of Supercritical Pressure Water in Vertical Upward Annular Channels

WANG Han, BI Qin-cheng, YANG Zhen-dong, WU Gang

2013, 34(4): 64-67,99.

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Within the range of pressure from 23 to 28 MPa,mass flux from 350 to 1000 kg/（m².s）,and outside wall heat flux from 200 to 1000 kW/m²,experimental investigation was conducted on the heat transfer characteristics of supercritical pressure water in vertical upward annular channels.The effects of heat flux,pressure,mass flux and spiral spacer on heat transfer were analyzed,and two types of heat transfer deterioration occurred in the experiments were compared.The experimental results show that the heat transfer of water can be enhanced by increasing the mass flux or decreasing the wall heat flux.The effect of pressure on heat transfer is not uniform and depends on heat transfer form.It was found that the spiral spacer not only enhances the heat transfer of water,but also delays the heat transfer deterioration which occurs in high heat flux and low mass flux conditions.

Study on Transition Criterion from Bubble Flow to Slug Flow in Rectangular Channels

WANG Yang, YAN Chang-qi, SUN Li-cheng, YAN Chao-xing, XING Dian-chuan

2013, 34(4): 68-72.

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Using air and deionized water as working fluids,flow pattern characteristics of two-phase flow was investigated experimentally for two vertical rectangular channels with the cross sections of 1.41×40mm² and 10×40mm².Experiment was conducted under atmospheric condition,and the superficial velocities of air and water were in the ranges of 0.015~0.59m/s and 0.025~3.74m/s.Four classical transition criteria from bubbly flow to slug flow are evaluated against present experimental data and that from open literatures.The result shows that the four transition criteria are limited to some extent.Through the analysis of the dataset,it is found that aspect ratio is a key parameter to determine the critical transition void fraction,for which two correlations are given according to the threshold of 10mm of the hydraulic diameter.As a result,the modified criterion is obtained and is satisfactory agreement with the present data and the existing experimental data,and it is better than four classical transition criteria.

Visualized Experimental Study on Sliding and Lift-Off of Bubbles in Narrow Rectangular Channel

XU Jian-jun, ZHUO Wen-bin, XIE Tian-zhou, CHEN Bing-de, HUANG Yan-ping

2013, 34(4): 73-78.

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The phenomenon on sliding and lift-off of bubbles in a narrow rectangular channel were observed through the top view and side view of the narrow rectangular channel using a high speed digital camera.In inclined upward facing upflow boiling and in vertical downflow boiling,the bubble tends to lift off from the surface.The bubble velocity increases after lift-off from the heating surface,and the condensation phenomenon of lift-off bubble will occur when the bulk flow is subcooling,which results in the change of bubble shape.Base on the experimental results,the effects of different flow mode and heating surface inclined mode on the sliding and lift-off of bubble are analyzed.

Visualized Study on Interface Shape and Growth of Sliding Bubble in Narrow Rectangular Channel

XU Jian-jun, ZHUO Wen-bin, XIE Tian-zhou, CHEN Bing-de, WANG Xiao-jun

2013, 34(4): 79-83.

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Sliding bubble interface shape and bubble growth for the isolated bubble region in a narrow rectangular channel were observed from the wide side and narrow side of the narrow rectangular channel using a high speed digital camera.The results show that the growth rate of sliding bubble is small,and the growth rate of a small bubble is slightly larger than that of a large bubble.The sliding bubble appears to be spherical in shape according to the observation from the wide side of the narrow rectangular channel,but the sliding bubble is elongated in the direction normal to the heating surface from the side view.During the process of sliding bubble along the heating surface,the upstream and downstream contact angles are almost equal in this experimental condition.

Numerical Simulation on Fluid Flow and Heat Transfer Characteristics of Narrow Rectangular Channel in Rolling Motion

LI Long-jian, DONG Xiang-lu, MA Jian, HUANG Yan-ping

2013, 34(4): 84-89.

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The three dimensional unsteady physical model and mathematical model of turbulent flow and heat transfer in the narrow rectangular channel were established,and the corresponding flow field and temperature field was numerically simulated.The time-averaged Nusselt number and time-averaged friction coefficients of the channel were investigated under different Reynolds number.The computed results showed that the time-average Nusselt number and time-averaged friction coefficient is larger slightly than the one in the steady-state,and both the Nusselt number and frictional pressure drop of the channel were oscillated periodically along with rolling period and rolling amplitude.

Dimensionless Analysis of Single-Phase Natural Circulation Characteristics for PWR under Ocean Condition

HAO Y-alei, YAN Bing-huo, YANG Xing-tuan, YI Xiong-ying

2013, 34(4): 90-94.

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The dimensionless equation for a single-phase natural circulation loop has been established with the Boussinesq approximation.Through the deduction of single-phase momentum and energy equations,influencing parameter of natural circulation flow in different outside conditions has been obtained.The effect of heeling,heaving and rolling on flow variation of natural circulation has been discussed and the conservation criteria of single-phase natural circulation flow constraint have been given.This study showed that the single-phase natural circulation flow rate decreased as the heeling angle increasing.The heaving impact on the natural circulation flow rate is small as the heaving acceleration is much smaller than the gravity acceleration.In different rolling conditions,the maximum rolling angular acceleration are the same for identical flow rate oscillating amplitude.The constraint criteria of single-phase natural circulation flow can be obtained through the subcooling of heat source.

Experimental Investigation on Local Parameter Measurement Using Optical Probes in Two-phase Flow under Rolling Condition

TIAN Dao-gui, SUN Li-cheng, YAN Chang-qi, LIU Guo-qiang

2013, 34(4): 95-99.

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In order to get more local interfacial information as well as to further comprehend the intrinsic mechanism of two-phase flow under rolling condition,a method was proposed to measure the local parameters by using optical probes under rolling condition in this paper.An experimental investigation of two-phase flow under rolling condition was conducted using the probe fabricated by the authors.It is verified that the probe method is feasible to measure the local parameters in two-phase flow under rolling condition.The results show that the interfacial parameters distribution near wall region has a distinct periodicity due to the rolling motion.The averaged deviation of the void fraction measured by the probe from that obtained from measured pressure drop is about 8%.

Sensitivity Analysis for Transient of Partial Loss of Reactor Coolant Flow of Super LWR

LUO Feng, ZHOU Tao, CHENG Wan-xu, SU Zi-wei, CHEN Juan

2013, 34(4): 100-105.

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Taking the Super LWR concept proposed by Japanese as the background,relevant mathematical and physical calculation models are built,and the effect of coast-down time of primary pump,scram delay and ratio of density coefficient on the maximum cladding surface temperature（MCST） is evaluated.The results show that: after the transient of partial loss of reactor coolant flow,due to the pump seize and reactor scram,the maximum cladding temperature increases quickly at first and then declines rapidly;extending the coast-down time of primary pump can delay the reduction in the flow of coolant,thereby delaying the increasing of maximum cladding temperature;scram delay is the shorter,thereby better slow down the maximum cladding temperature;Ratio of density coefficient affects the maximum cladding temperature changes a little.Visibly,the coast-down time of primary pump or the scram delay can be a significant impact on the safety performance of the core.

Transient Safety Analysis of Subcritical Energy Reactor

MA Ji-min, LIU Yong-kang, LI Mao-sheng

2013, 34(4): 106-110.

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The system model of Subcritical Energy Reactor（SER） was primarily established,which was based on SER conceptual design and by taking PWR loop model as references.With RELAP5/MOD3.3 code,initial steady state and transient conditions including power increase accident,loss of coolant flow accident and loss of heat sink accident were analyzed.The results show the limit value during the accidents and make the safety characteristics of SER clear.Suggestions have been offered for SER safety.The work could give references for the following conceptual design and engineering design in hybrid energy reactors.

Analysis of Loss of Offsite Power and Loss-of-flow Accident of HFETR

SUN Shouhua, XU Taozhong, LI Ziyan, LI Jingsong, DENG Caiyu

2013, 34(4): 111-113,125.

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The High Flux Test Reactor（HFETR） was assumed encountering blackout and three of four pumps seizure during 70 MW operation,then the primary and secondary loop lost flow,and the reactor shut down automatically.Variation of temperature of hot pipe wall,void fraction and equilibrium quality with time were analyzed with and without intervening respectively in this paper.The results showed that the safe time without intervening was 9221 s after accident and if the feeding water pumps were turned on in 900 s after accident,the safety of the reactor could be ensured.

Application of RCM in Ensuring Reliability of ARMS in Tianwan Nuclear Power Station

BAI Xiao-bo

2013, 34(4): 114-116.

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The paper provides the analysis and summary of the ensuring of the ARMS reliability through reliability design of module,redundancy design of system and state monitoring,periodical maintenance,periodical experiment,corrective repair,technological improvement in the view of Reliability-Centered Maintenance（RCM）,integrating the working practice of commissioning,operation and maintenance,and puts forward some propositions in the information collection,equipment classification,preparation of personnel about the application of RCM for ARMS maintenance in the future.

Nuclear Safety Review for Qualification of Class 1E Motor inside Containment for Nuclear Power Stations

LI Shi-xin, WU Qi, ZHANG Yun-bo, WU Cai-xia

2013, 34(4): 117-120.

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In nuclear power plants with pressurized water reactors,the review for class 1E motor inside containment qualification process and documents is an important aspect of nuclear safety equipment review,and the reviewers should make evaluations for the qualification test results in terms of the compliance with standard and regulation,and the consistency with inside containment environment.Firstly,this paper introduces the qualification test of class 1E motor inside containment for nuclear power generating stations,such as aging test and design-basis-event test.Second,there is a discussion about typical problems of review.At last,comparison of IEEE334 with RCC-E is conducted and explored.

Online pH Monitoring and Control of Radioactive Waste Liquid in Evaporation Treatment System

YU Ren, KONG Jing-song, GUO Wei-qun

2013, 34(4): 121-125.

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A compound control method which has different control algorithms at different slice time or different condition is adopted to solve the problem of pH monitoring and automatic control of radioactive waste liquid in an evaporation treatment system.Both the feed forward and backward functions are utilized in the method.The architecture and work manner of the pH monitor and automatic adjustment system is introduced,as well as the control algorithms at different condition.The method can diminish the effects caused by the nonlinearity and lag characteristics of radioactive waste liquid pH control,and achieve properly the automatic adjustment of pH value of the loading waste liquid for the evaporation treatment system.

Design and Analysis of Throttle Orifice Applying to Small Space with Large Pressure Drop

LI Yan, LU Dao-gang, CENG Xiao-kang

2013, 34(4): 126-129.

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Throttle orifices are widely used in various pipe systems of nuclear power plants.Improper placement of orifices would aggravate the vibration of the pipe with strong noise,damaging the structure of the pipe and the completeness of the system.In this paper,effects of orifice diameter,thickness,eccentric distance and chamfering on the throttling are analyzed applying CFD software.Based on that,we propose the throttle orifices which apply to small space with large pressure drop are multiple eccentric orifices.The results show that the multiple eccentric orifices can effectively restrain the cavitation and flash distillation,while generating a large pressure drop.

Dynamic Load Protection Technology for Nuclear Upender and Its Application

ZHAO A-peng, ZHANG Qiang, ZHANG Mei-ling, WU Feng-qi, LU Xiu-sheng

2013, 34(4): 130-132.

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As key parts of nuclear fuel assembly’s transport,the nuclear upender’s reliability is significantly important for nuclear safety.By load analysis and simulation,we establish a new mechanical model between upender’s position and load.It also mentions a new kind of dynamic load protection means by comparing the load values with adjusting overload and under load values according to upender’s position.The experiment results show that the new technology can provide more effective protection to ensure no leakage occurred due to accidental forces applied on it.

Study on Solutions to Sensor Support Setting Resonance of Nuclear Power Half-Speed Turbo-Generator

GAO Pei

2013, 34(4): 133-135,139.

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The root cause of the high on-line vibration measurement of the nuclear power half-speed turbo-generator is studied,and the result shows that the first natural frequency of the sensor support setting isclose to the forth times harmonic wave of the generator speed frequency,that is the root reason of the high on-line vibration.This paper uses the three-dimension modeling software to make fixture mode of the sensor support setting,and utilize finite element analysis（FEA） software to analyze and calculate its frequncy characteristics.Two schemes are offered by adding a mass block or increasing the stiffness of the sensor support setting,that change the natural frequency.So the resonance is avoided,and the authenticity and effectiveness of the on-line vibration is ensured.

Analysis of High On-Line Vibration Measurement of Nuclear Power Half-Speed Turbo-Generator

GAO Pei, WANG Wei, CHEN Yong, WAN Ping-sheng

2013, 34(4): 136-139.

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Aiming at the problem of the high on-line vibration of the nuclear power half-speed turbo-generator,this paper made a step-by-step analysis according to the vibration spectrum,off-line vibration test,electromagnetic interference verification,and natural frequency knock test.Finally a conclusion was made that the natural frequency of the sensor support setting is close to the four times harmonic wave of the generator operating frequency,resulting in sensor support setting resonance,which is the key reason of the high on-line vibration measurement.

Study on Chain Relationship between Condenser and Vacuum Isolation Valve

SHANG Xian-you, SHI Jian-zhong, WANG Xue-hua, HU You-qing, SHI Ying

2013, 34(4): 140-142.

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In the condenser unilateral isolation conditions,the corresponding vacuum isolation valve should be shut down at the same time,and in any case,it is not recommended to open the valve,otherwise some consequences would occur,such as the increasing of non-condensable gas of the condenser,and degrading of vacuum pump performance and condenser performance.This paper makes a comparison of unilateral isolated condition and the normal operation condition,and analyzes the condenser leakage,non-condensing gas accumulation trends,vacuum pump performance,and the performance of the condenser.

Study on Ultrasonic Inspection Technology for Reactor Pressure Vessel Stud

ZHANG Guo-feng, ZHANG Bao-jun, YAN Zhi, JIN De-rong

2013, 34(4): 143-146.

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During the PSI or ISI in NPPs,the RPV stud must be inspected according to the ASME code section XI,and the best method for the volume inspection is ultrasonic test.This paper introduces the technology of scanning inside the central hole and scanning from the end surface of the stud,and details the block designing,apparatus choosing,signal cable selection,noise decreasing,probe designing,signal identification,defect evaluation and location technology.This technology can detect the flaw of 0.5 mm in depth on the thread area and screw area of the stud out surface.And the SNR can be 12dB higher.The location precision of axial is ±1mm;and the location precision of circumferential is ±2mm.Finally we developed the UT of RPV stud technology successfully,which are qualified and validated in fieldwork.

Cause Analysis and Countermeasures for Valve Failure of Radioactive Liquid Waste Treatment Facilities

KONG Jing-song, YU Ren, MENG Kai

2013, 34(4): 147-148,184.

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The valve type and valve failure characteristics of radioactive waste treatment facilities are introduced in this paper.The result shows that most of the valve failure is resulted from the creep of mechanical joint and the destructive impurity in the medium.The cycle time for valve failure is 1 to 2 years.The suggestion for maintenance method,maintenance cycle time and maintenance procedure are pointed out.

Conception Design of Shielding Collimator System for High Energy Neutron Radiography with Minitype Neutron Source

WU Yang, DOU Hai-feng, TANG Bin, HUO He-yong

2013, 34(4): 149-152.

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Shielding collimator system is necessary in the neutron radiography installation;this issue gives the conception design of shielding collimator system for FNR about high energy neutron source by MCNP.Preliminarily ascertain the material component and dimension,confirm the neutron flux at imaging position,imaging distance,imaging field range of the FNP installation in theory.

Ansys CFX Thermal Analysis of Modular Tube-Type Irradiation Rig

YANG Wen-hua, TONG Ming-yan, SUN Sheng

2013, 34(4): 153-156.

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The Modular Tube-type Irradiation Rig（MTIR） is designed to conduct various material performance tests in high flux region of the High Flux Engineering Test Reactor（HFETR）.Using Ansys CFX to establish a mathematical model,a simulation study on thermo-technical characteristics of MTIR is performed.The analysis shows that the results from the material irradiation test in HFETR are in good agreement with the analysis results by Ansys CFX,which shows that the results about the steady-state thermal analysis are correct,and it provides the basic research on the design of MITR.

Research and Development of A New Speediness Disassembly Tie-In for Advanced Fuel Assembly

HUANG Xin-dong, HUANG Hui, HONG Long, TAN Hong-wei

2013, 34(4): 157-160.

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This paper briefly introduces the pressurized water reactor fuel assembly structure,and analyzes the detachable joint problems and technical features.On this basis,a design scheme of connection structure of PWR fuel detachable is proposed,and based on the experiment results,the structure is optimized.Experiment on the optimized structure shows that after repeated disassembly,each test piece can satisfy the design requirement on flexible rotation,reliable locking,convenient disassembly and assembly,and exchangeability.

Development of Long Shank Repair Tool for Defect of Pressure Vessel Bolt Hole in Pressure Vessel of Nuclear Power Plant

HUANG Xin-dong, HUANG Hui, HONG Long, LI Xin

2013, 34(4): 161-163.

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In the reactor operation and operations with open lid,various defects may emerge on thread section of the main bolt hole pressure vessel.These defects must be dealt with before the closing of the lid.In view of the above conditions,this paper developed a pressure vessel screw rod cutter device,and expounds the long shank repair tool,a detailed description of the design scheme of the tool as well as the concrete structure.

Experimental Research of Cutting Stainless Steel by High Pressure Abrasive Water Jet under Water

LU Xian-jing, SI Dan-dan, TONG Ming-yan, SUN Sheng, WU Jing, YANG Wen-hua, ZHANG Ping

2013, 34(4): 164-167.

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The High Pressure Abrasive Water Jet is designed to cut stainless steel under water at the pressure of 320,350,380 MPa,with 2,5,and 8 mm target distance,and six cutting velocity.The effects of pressure,target distance and velocity on cutting thickness are analyzed,and then a half-experience math model is established based on the test data.The data analysis shows that pressure,target distance and velocity have exponential relation with cutting thickness.

Building of a CAD System for I＆C System of Nuclear Power Plant

MA Zhi-cai, ZHANG Dong-sheng

2013, 34(4): 168-170.

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An I＆C database was developed based on the design objects and properties presented in I＆C design documents of nuclear power plant.With the database,a rapid-implemented CAD system for I＆C engineering was designed and implemented with popular CAD software,AutoCAD and Visio,and desktop database management system,Access,to manage the design data and to automate the composing task for listings,forms and drawings.This system was applied in an engineering project for data management,document generation and drawing aid,and demonstrated its usability and efficiency.

Study on Fretting Characteristics of Si₃N₄/NS315 Alloy at High Temperature

LI Gen, LIU Han-wei, REN Ping-di, ZHANG Xiao-yu

2013, 34(4): 171-175.

Abstract(13) PDF(0)

Abstract:
The fretting wear behaviors of NS315 alloy were studied experimentally on a high precision hydraulic fretting wear machine at room temperature（25℃） and 300℃.This paper was designed to analyze the the friction characteristic curve,the fretting coefficients and the morphology of the worn surface,and the mechanism of fretting wear was discussed.Experimental results shows that the fretting wear of NS315 alloy is in a slip regime when the displacements are 80~200 μm.Friction Coefficient was not significantly related to the displacements but increased according to the normal load’s increment.Compared to the room temperature,NS315 Alloy got a higher friction coefficients,and the worn volume was larger at 300℃.The wear mechanism of the NS315 Alloy at 25℃ were mainly a combination of abrasive wear,delamination and oxidization wear,yet oxidization wear and delamination at 300℃.

Simulation Research on Path Planning of Nuclear Emergency Decision with Constraints

WEI Qiang, ZHU Bo, XIE Zhang-ji

2013, 34(4): 176-179.

Abstract(18) PDF(0)

Abstract:
Path planning in the radioactive environments is an important part of nuclear emergency decision system.An optimal work rout can help to reduce the radioactive dose to workers,preventing the workers from more harm.The ant algorithm is introduced in this paper,helping to plan the work rout in the radioactive environments.At the end of this paper,it takes an radioactive worksite as an example,carries on the simulation research of path planning with constraints of time and dose,and gets the optimal movement path.

Research and Practice of Informatization Construction in Waste Treatment and Management

KONG Jing-song, YU Ren, GUO Wei-qun, XIANG Xin-min

2013, 34(4): 180-184.

Abstract(18) PDF(0)

Abstract:
The goal,content and requirement of the informatization construction in waste treatment and management in nuclear power system are discussed in the paper,as well as some key problems in this process.Taking the engineering practice of informatization construction in a waste treatment center as an example,the composition and architecture of the information system,the consideration and the solution methods of some key problems in system design and development are introduced in the paper.

PRA Quality in Risk-Informed Application of Nuclear Power Plant

LI Chun, YI Yan

2013, 34(4): 185-188.

Abstract(17) PDF(0)

Abstract:
Based on the technology of PRA that was moved forward to use in the nuclear power plant by the United States Nuclear Regulatory commission（NRC）,this paper introduced the meanings of PRA quality,the phased approach to improve the PRA quality in the U.S.NRC,and the background of the regulatory guides.Combined with the status of PRA applications in China,an acceptable method to improve the PRA quality is proposed.

2013 Vol. 34, No. 4