核动力工程

Evaluation of Heat Transfer Correlations for Supercritical Carbon Dioxide in Circular Tubes under Heating Conditions

Huang Yanping, Liu Guangxu, Wang Junfeng, LÜ； Fa

2014, 35(3): 1-5. doi: 10.13832/j.jnpe.2014.03.0001

Abstract(12) PDF(0)

Abstract:
This paper presents a review of heat transfer correlations for supercritical carbon dioxide in circular tube under heating conditions. All of these reviewed correlations were preliminarily evaluated based on experimental data in open literature. The results showed that most of these heat transfer correlations have the general form of classical single phase heat transfer correlations with some modifications. Among these correlations, Jackson correlation and Krasnoshcheko correlation agreed well with experimental data, however, poor agreement was found for all of the reviewed correlations in near-critical region.

Numerical Analysis on Transient Flow and Temperature Field During Inlet Flow Blockage Accidents of Plate-type Fuel Assembly

Song Lei, Guo Yun, Zeng Heyi

2014, 35(3): 6-10. doi: 10.13832/j.jnpe.2014.03.0006

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Abstract:
Due to its superior performances such as compact structure, higher heat transfer efficiency, and deeper fuel burn-up, plate-type fuel assembly has been more and more widely utilized in new type integrated reactors and experimental research reactors, of which coolant is forced passing through the typical narrow rectangular channels formed by plate-type fuel in the core. Under some postulated accident conditions, such as irradiation damage, materials debris or foreign objects dragged into the core with the coolant circulation, and coolant flow assembly blockage accidents could occur. The accident may cause the reduction of coolant flow, make the fuel plate temperature increased, result in the phenomenon of dry-out, threaten the integrity of fuel cladding, and even cause the release of radioactive material into the reactor coolant system. The transient thermal-hydraulic characteristics of plate-type fuel assembly under inlet 95% partial and total flow blockage transient accidents are numerical simulated using the commercial CFD software ANSYS FLUENT 12.1 code. The liquid-solid conjugate heat transfer between coolant and fuel-plates has been considered in this calculation, and we analyzed the three-dimensional flow field, temperature field and the influencing factors.

Study on Reverse Flow in U-Tube Steam Generator under Natural Circulations

XiN Sufang, Peng Shinian, Zhang Yu

2014, 35(3): 11-14. doi: 10.13832/j.jnpe.2014.03.0011

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Abstract:
Some U-tubes are with flow in the reverse direction under natural circulations, which increases the equivalent local resistance of steam generator and decreases the flow of loop compared to the prediction without considering reverse flow. The stability of flow in a U-tube is discussed based on one-dimension momentum equation in this paper. On this basis, the range of the fraction of U-tubes with reverse flow can be derived from the conservation equations. The effect of loop resistance coefficient and numbers of U-tubes on the fraction of U-tubes with reverse flow is also discussed in this paper. The results show that the decreasing of the loop resistance coefficient and number of U-tubes contributes to decrease the fraction of U-tubes with reverse flow.

Modification and Analysis of Engineering Hot Spot Factor of HFETR

Hu Yuechun, Deng Caiyu, Li Haitao, Xu Taozhong, Mo Zhengyu

2014, 35(3): 15-17. doi: 10.13832/j.jnpe.2014.03.0015

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Abstract:
This paper presents the modification and analysis of engineering hot spot factors of HFETR. The new factors are applied in the fuel temperature analysis and the estimated value of the safety allowable operating power of HFETR. The result shows the maximum cladding temperature of the fuel is lower when the new factor are in utilization, and the safety allowable operating power of HFETR if higher, thus providing the economical efficiency of HFETR.

Comparison between Air-cooled and Water-cooled Schemes for the Passive Residual Heat Removal System of Molten Salt Reactor

SuN Lu, SuN Licheng, Yan Changqi, FA Dan, Wang Naxiu

2014, 35(3): 18-21. doi: 10.13832/j.jnpe.2014.03.0018

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Abstract:
The water-cooled and air-cooled passive residual heat removal systems（PRHRSs） were designed for 10MW molten salt reactor experiment（MSRE）, according to which the mathematical models were established and numerically solved in the code of C++. Main characteristics of the two systems were given and compared. The results show that both water-cooled and air-cooled PRHRSs can establish stable natural circulations and meet the design requirements for heat removal. However, the air-cooled PRHRS has better comprehensive performance for long term cooling.

Numerical Study on Forced Convection in Sub-Channel with Grid Spacer in Supercritical Reactor Core

Zhu Xiaojing, Liu Liujing, SHen Shengqiang

2014, 35(3): 22-25. doi: 10.13832/j.jnpe.2014.03.0022

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Abstract:
Numerical analysis is carried out for the effects of grid spacer on the forced convection of supercritical water in the sub-channels in supercritical reactor core with commercial CFD code using unstructured polygonal mesh. The results show that the grid spacer has great effects on the heat transfer characteristics of supercritical water within sub-channel. The grid spacer with flow-blockage disc can neutralize the aggravated flow chocking effect by blocking and guiding the flow around the sub-channel center and enhance the local heat transfer near the narrow gap region. Obvious swirling flow is created downstream of the grid spacer with split-vans and the heat and mass transfer between adjacent sub-channels is thus enhanced. The swirling flow can also induce velocity deficits and adversely affect the local heat transfer inside a sub-channel. The Re number has obvious effects on the local heat transfer downstream of the grid spacer with split-vans, and the improved heat transfer performance downstream of the grid spacer with split vanes is more pronounced for the higher Reynolds number case.

Experimental Study on Type I Density Wave Oscillation in Parallel Twin Rectangular Channels under Forced Circulation

Tang Yu, Chen Bingde, Xiong Wanyu, Wang Yanlin

2014, 35(3): 26-30. doi: 10.13832/j.jnpe.2014.03.0026

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Abstract:
An experiment has been made on Type I density wave oscillation（D.W.O） in a 50mm×2 mm parallel rectangular channels at the pressure of 2~8 MPa. The region of operation condition in which the Type I appeared was obtained. The effects of system pressure, mass velocity and inlet subcooling on the boundary parameters were also been investigated. Finally, the distribution of instability points was given on Npch-Nsub figure and the empirical correlation of dimensionless boundaries has been made based on the experimental results.

Study on Liquid-Slug Characteristics of Slug Flow in Narrow Rectangular Channel

Wang Yang, Yan Changqi, SuN Licheng, Yan Chaoxing, Tian Daogui

2014, 35(3): 31-36. doi: 10.13832/j.jnpe.2014.03.0031

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Abstract:
Gas-liquid slug flow is widely encountered in many practical industrial applications. A detailed understanding of the hydrodynamics of the liquid slug has important significance for modeling slug flow. A high speed video camera system is applied to visually study the liquid-slug characteristics of slug flow in a vertical narrow rectangular channel（3.25×40mm2）. It is found that the stable liquid slug in the narrow rectangular channel consists of three regions: wake region of leading slug, recovering region of the velocity profile to main flow, stable main flow region. The wake region of leading slug is resulted from the jet of the wall liquid film in the wake of leading gas slug. The position of trailing gas slug in the liquid slug has significant influence on its characteristics. The leading slug also has enormous effect on the trailing slug in laminar or transition flow. The minimum stable liquid slug length Lmin is referred to the length of axial velocity profile near wall region in the liquid slug approaching to fully developed turbulence region（ReTP＞9000）, Lmin increases with increasing slug length and varies inversely with two-phase Reynolds number, and it is in the range of 9-17Dh.

Research on Pressure Oscillation Amplitude Induced by Steam Jet Condensation in Water

Wu Xinzhuang, Guo Dandan, Tian Lin, Pan Rudong, Qiu Binbin, Zhong Daotong, Yan Junjie

2014, 35(3): 37-41. doi: 10.13832/j.jnpe.2014.03.0037

Abstract(14) PDF(0)

Abstract:
In order to obtain the pressure oscillation characteristics induced by steam jet in water, the experimental method was used to investigate the pressure oscillation in a wide range of steam mass fluxes and water temperatures. The pressure oscillation amplitudes at various positions were measured using high frequency pressure sensor, and the effects of steam mass flux and water temperature on the amplitude were analyzed combined with the flow patterns. The results indicated that the pressure oscillation was intense at condensation oscillation region, and was relaxative at stable steam jet region. The amplitudes decreased firstly then increased with the steam mass flux due to the transition of flow patterns. Moreover, the amplitudes increased with water temperature, and especially as the water temperature was higher than 40℃, the flow pattern became divergent which leaded to a significant increase in amplitude.

Analysis of Core Barrel Flange in LOCA under Two Point Contact with Hold Down Spring

Fang Jian, Duan Yuangang, Ran Xiaobing, Dai Zhangnian

2014, 35(3): 42-45. doi: 10.13832/j.jnpe.2014.03.0042

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Abstract:
To obtain the real contact condition between core barrel flange and hold down spring, and to obtain accurate results of analysis of Core Barrel Flange in the Case of LOCA, this paper introduced the main loads applied on CERP core barrel flange, especially, the load applied by hold down spring in the case of two-phase LOCA under the mode of "two point contact". This paper presented an analysis of core barrel flange in LOCA condition based on SYSTUS, obtained the stresses of core barrel flange in LOCA condition by comparing displacements and estimated the behavior of core barrel flange according the rules of RCC-M.

Study on Fatigue of Reactor Coolant Piping and Minimum Piping Wall Thickness

ZhOu Zhou, Meng Shaopeng, Bao Jie

2014, 35(3): 46-50. doi: 10.13832/j.jnpe.2014.03.0046

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As a core issue in fatigue qualification for nuclear power plant reactor coolant piping, FEM thermal transient analysis are used to pursue the wall thickness thermal field, instead of finite difference equation, which could be brought to the Code equation for fatigue analysis by solving the transient alternating stress amplitude. Calculation methodology, Optimization algorithm for minimum wall thickness, and flow chart of iterative solution are addressed in this paper, those items can be achieved programmatically.

Application of Statistical Process Control Technology in Pre-Stressing Analysis of Reactor Pressure Vessel Bolts

Zhang Tao, Xiao Lingmei, Li Tenglong

2014, 35(3): 51-54. doi: 10.13832/j.jnpe.2014.03.0051

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Abstract:
Based on the analysis of the pre-stressing installation process for pressure vessel bolts in nuclear power plant, a method of using statistical process control（SPC） technique for the analysis of the bolt pre-stressing was proposed, and an automatic data acquisition implementation scheme was designed. Data analysis results demonstrated the accuracy of the method, and it can be used to analyze the pre-stressing and evaluate the quality of the pressure vessel installation in nuclear power plant.

Design of Protection Logic Channel Test Device for Reactor Protection System

Kang Ya, Zhu Pan

2014, 35(3): 55-58. doi: 10.13832/j.jnpe.2014.03.0055

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A protection logic channel test device is used in the periodic test of protection logic for reactor protection system in Qinshan Phase II extension project. This paper introduces test principle, equipment composition, working style, technique characteristics and etc. of the device.

Optimization Design of Reactor Lower Plenum

Zhang Hongliang, Liu Haipeng, Fang Caishun, Lu Chuan

2014, 35(3): 59-63. doi: 10.13832/j.jnpe.2014.03.0059

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Characteristics of the reactor lower plenum are analyzed by CFD, which are focused on the stability and reliability of structures and the equality of the flowing. After refinements and improvements, better reactor lower plenums are got, which are simple, stable and equability flowing.

Design Optimization on Structure of Blowdown in CPR1000 Steam Generator

Wang Guoxian, Ren Hongbing, Zuo Chaoping, Zhu Yong, MO Shaojia

2014, 35(3): 64-68. doi: 10.13832/j.jnpe.2014.03.0064

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Abstract:
The structure of blowdown in CPR1000 steam generator has been optimized by eliminating the blowdown pipe and tube lane blocking, drilling holes in the peripheral tube lane, which can improve the accessibility of the central tube lane and facilitate inspecting and lancing. This paper detailed compares and analyzes the thermal hydraulic characteristic before and after optimization using GENEPI code which a special software for SG thermal hydraulic analysis. The results showed that the thermal hydraulic characteristic of steam generator meets the design requirements compared with the original design. Structure optimization can improve lancing effects, although the change of flow field distribution above the tubesheet leads to increase the number of tube subjected to sludge deposit. The analysis results proved the feasibility of the optimization.

Numerical Simulation on Ventilation Heat Transfer of Control Rod Drive Mechanism

ZhenG Maoxi, Li Yuezhong, Ran Xiaobing

2014, 35(3): 69-72. doi: 10.13832/j.jnpe.2014.03.0069

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Abstract:
The ventilation heat transfer of CPR1000 Control Rod Drive Mechanism（CRDM） is simulated when CRDM continuous insertion action by using the ANSYS CFX software. The CRDM coils temperature, the relationship between cooling air flow and the CRDM coils temperature, CRDM air flow pressure drop in cooling channel, CRDM heat dissipating capacity and heat transfer coefficient are analyzed. The comparison between the simulated results and the test results shows that the numerical simulation method is acceptable.

Technical Improvement of Shims and Its Procedure for Gap Measurement and Adjustment for CPR1000 Steam Generator Upper Horizontal Support

Xie Honghu, ZhOu Peng, Liang Xiaolong, Liu Xiaohua

2014, 35(3): 73-75. doi: 10.13832/j.jnpe.2014.03.0073

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Abstract:
Taking China Modified Pressure Reactor 1000 MW nuclear electrical station（CPR1000）steam generator（SG） as an example, the origin for the difference between gap measured and real gap for the thermal expansion of SG upper horizontal support is analyzed, and the optimized schemes ware proposed to improve the shim structure and the procedure about gap measurement and adjustment. The results show that the scheme is an effective way to solve the difficulties met during gap measurement and adjustment.

Disposition of Drilling Deviation for Steam Generator Tubesheet in Sanmen NPP Unit 2

Du Nanlin, Chen Zhongzhuo, Chen Fubin

2014, 35(3): 76-79. doi: 10.13832/j.jnpe.2014.03.0076

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Abstract:
Abatract: Deep hole drilling of steam generator tube sheet assembly is an important process for SG fabrication. This process is always difficult during manufacturing. The SG Tube sheet of Sanmen AP1000 Units is thicker than that of Nuclear Power Generate II+. The difficulty of Tubesheet Drilling also grows with the larger thickness. This paper describes the disposition of SG Tube sheet drilling deviation for Sanmen Nuclear Power Plant Unit 2. It is expected to provide some useful experience for the future SG manufacturing, avoiding such problem occurs again.

Application of Remote Mounting Intelligent Positioner on Turbine Bypass Valve

Wu Weixin

2014, 35(3): 80-82. doi: 10.13832/j.jnpe.2014.03.0080

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The fault of steam turbine bypass drain valve in the use process is analyzed. The remote mounting intelligent positioner is used to replace the original mechanical positioner and electric pneumatic converter. The impact on the steam turbine bypass drain valve due to in-situ vibration and high temperature is reduced. ValveLink software self tuning and fault analysis is adopted to test the valve after the completion of installation. The valve positioner parameters is optimized to solve the oscillation problem occurred in the valve adjustment. Through the use of isolation module, the independent power supply to handling the control circuit load problems are solved. The control stability and the safety of the turbine bypass valve is improved.

Power Up-rates Analysis of 310 MW Unit in Qinshan NPP

Huang Zhijun

2014, 35(3): 83-87. doi: 10.13832/j.jnpe.2014.03.0083

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The power up-rates analysis of 310MW unit in Qinshan NPP is based on the main equipment potential. The preliminary power for up-rates is defined and the problems which affect the up-rates are identified through theory analysis. The tests are performed according to the theory analysis. The parameters of primary loop and second loop are adjusted. The final power rating is confirmed on the basis of tests.

Vaccum Degas Technology for Primary Loops of Pressurized Water Reactor

Tan Haibo, Zhao Xin, Yang Sengai, Hui Longwei, Bai Xuan

2014, 35(3): 88-91. doi: 10.13832/j.jnpe.2014.03.0088

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At the start-up stage of pressurized water reactor（PWR）nuclear power station,the primary loops shall be degasified. Compared with the traditional degas method, the primary loops vacuum degas technology can not only shorten the test time, also greatly reduce the risk of the primary pump at the first starting. Technology of the primary loop vacuum degas is widely used in starting-up of the CPR1000 unit, after many tests and continuous improvement, this technology has been well established. Technology of the primary loops vacuum degas technology is introduced in this paper.

Fault Diagnosis for Nuclear Power Plant Regulator Pressure Transient Fluctuations

Chen Yongwei, Qiu Hewen, Fu Jingqiang

2014, 35(3): 92-96. doi: 10.13832/j.jnpe.2014.03.0092

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Diagnosis of the phenomenon of the pressure control signal fluctuation in nuclear power station and troubleshooting of the problem are carried out. Firstly, the RCA root cause analysis method is used to list the possible causes, and with signal simulation tool to position the abnormal module. And then some tests on the abnormal module offline is conducted to reproduce the fault, and the correctness of the fault location is verified. The real condition signal is used as the simulation source and injected into the control system. The signal trends between the real and simulation system is compared to troubleshoot the signal infrequent anomalies.

Application of Improved Degree of Grey Incidence Analysis Model in Fault Diagnosis of Steam Generator

Zhao Xinwen, Ren Xin

2014, 35(3): 97-101. doi: 10.13832/j.jnpe.2014.03.0097

Abstract(16) PDF(0)

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In order to further reduce the misoperation after the faults occurring of nuclear-powered system in marine, the model based on weighted degree of grey incidence of optimized entropy and fault diagnosis system are proposed, and some simulation experiments about the typical faults of steam generator of nuclear-powered system in marine are conducted. And the results show that the diagnosis system based on improved degree of grey incidence model is more stable and its conclusion is right and can satisfy diagnosis in real time, and higher faults subjection degrees resolving power can be achieved.

Research on Method for Estimating Rapidly Water Temperature of Spent Fuels Storage Pool

Hu Yuechun, Li Haitao, DenG Caiyu, Xu Taozhong, MO Zhengyu

2014, 35(3): 102-104. doi: 10.13832/j.jnpe.2014.03.0102

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In order to avoid the analysis of the actual heat transfer and process, from the point of view of energy balance, a method that can quickly estimate water temperature of spent fuels storage pool is presented. The water temperature with the method when the spent fuels were transferred into spent fuels storage pool during the major overhaul of High Flux Engineering Test Reactor（HFETR） is calculated, and the calculation results were verified by recording the actual water temperature. The results show that the method can successfully and rapidly estimate the water temperature, and the calculation results are reliable.

Visual Monitoring Path Forecasting Method for Digital Human-Computer Interface in Nuclear Power Plant and Its Application

Hu Hong, Zhang Li, Jiang Jianjun, Yi Cannan, Dai Licao, Chen Qingqing

2014, 35(3): 105-110. doi: 10.13832/j.jnpe.2014.03.0105

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Sometimes, the operators can not judge next possible monitoring object which would lead to monitoring delay or transfer error in the monitoring digital human-computer interface parameter information process in nuclear power plant. Aiming at the situation, the forecasting path plan method including forecasting path model, forecasting path plan algorithm and the calculation method of transfer path success probability and which is based on Markov process was proposed. Then the monitoring transfer behavior of the operators when SGTR（Stream Generator Tube Rupture） occurred abruption accidents is analyzed based on the method proposed in this paper, taking the digital human-computer as the source node of monitoring task of t time, the transfer path of next monitoring object was obtained successfully to improve the efficiency of monitoring and to minimize the risk of monitoring error, which will also contribute to analyze the driving mechanism of operators’ monitoring activities, to train simulated for monitoring behavior, and to optimize the digital man-machine interface.

Mechanism Study on Bubble Dynamics in Rectangular Pipes Based on CFD Method

Gong Daxin, Huang Shanfang, Wang Kan, Wang Fuyue, ZhOu Linglan

2014, 35(3): 111-116. doi: 10.13832/j.jnpe.2014.03.0111

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Numerical simulation on the movement of a single bubble as well as double bubbles was conducted with the VOF model based on computed fluid dynamics（CFD）. The simulation results agree well with the experimental observations. For a single bubble, the rising process includes accelerating vertically and swinging up. At the later stage, the trajectory is sinusoidal. The bubble’s stable velocity is determined by Eo number. For the two bubbles, coalescence may occur with an up-and-down structure. On the other hand, with a horizontal distribution, the two bubbles will separate and draw near regularly. The latter two decide the radial distribution of bubbles. From the results, the CFD method can well simulate the movement of bubbles, which is the basis of further study on bubble distribution with different buoyancies in natural circulation.

Research on Perturbation Based Monte Carlo Criticality Search Method

Li Zeguang, Wang Kan, DenG Jingkang, Li Yangliu

2014, 35(3): 117-120. doi: 10.13832/j.jnpe.2014.03.0117

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A new Monte Carlo criticality search method based on perturbation calculation is Carry out in this paper to overcome the disadvantages of traditional method. By using only one criticality run to get initial keff and differential coefficients of concerned parameter, the polynomial estimator of keff changing function is solved to get the critical value of concerned parameter. The feasibility of this method is tested, and results show that the accuracy and efficiency of perturbation based criticality search method is quite inspiring and overcomes the disadvantages of the traditional method.

Research on Electromagnetic Characteristics of Pressure Vessel in CRDM using Finite Element Method

Xie Ximing, Zhang Zhifeng, Li Wei, SuN Qihang, DenG Qiang

2014, 35(3): 121-124. doi: 10.13832/j.jnpe.2014.03.0121

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In this paper, the electric-magnet characteristics of the pressure vessel in CRDM drive motor is studied by the Finite Element Method. The influence law on the he electric-magnet characteristic is studied through analyzing the output torque of drive motor in different pressure vessel material or in different structure size. The result shows that the electric-magnet characteristic of the pressure vessel in CRDM drive motor can be acquired accurately by the Finite Element Method, which has advantages on reducing design time and physical prototype experiment cost.

Study on Criteria for Hydrogen Flame Acceleration at Elevated Temperatures and Pressures

PenG Huanhuan, Yu Hongxing, ZOu Zhiqiang, Tang Chen, Zhu Li

2014, 35(3): 125-128. doi: 10.13832/j.jnpe.2014.03.0125

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Based on the physical phenomena of hydrogen flame acceleration, the present paper introduced the σ criteria for hydrogen security analysis of flame acceleration. From the quench/re-ignition of flammable gas mixture theory, the flame acceleration criteria at elevated temperatures and pressures was been put forward by considering the effect of laminar flame velocity from pressures and been validated by hydrogen defragration and detonation experiments at elevated temperatures and pressures.

Matrix Method of Characteristics Based on Modular Ray Tracing（1）——Theory

Wu Wenbin, Li Qing, Wang Kan

2014, 35(3): 129-133. doi: 10.13832/j.jnpe.2014.03.0129

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Matrix MOC based on modular ray tracing consuming less memory for geometrical information was studied. Method making use of the symmetry of problems based on modular ray tracing was proposed which reduces memory demands and improves efficiency furthermore. The numeric properties of the coefficient matrix were dug out by analysis of the construction process, due to which constructing computation and memory demand can be reduced significantly. In case of upscatter, multi-group GMRES based on Matrix MOC and its numeric properties was studied for accelerating the multi-group iterations.

Matrix Method of Characteristics Based on Modular Ray Tracing（2）——Numerical Verification

Wu Wenbin, Li Qing, Wang Kan

2014, 35(3): 134-137. doi: 10.13832/j.jnpe.2014.03.0134

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In the companion paper, Matrix MOC based on modular ray tracing was studied, the numeric properties of the coefficient matrix were analyzed and multi-group GMRES method was proposed. Based on these theories, a modular ray tracing MOC code was developed in CPP programming language. To verify the efficiency and accuracy, three benchmarks were computed, which are BWR lattice benchmark, UO2 assembly and 2D C5G7 benchmark. Numerical results of the benchmarks demonstrate that Matrix MOC based on modular ray tracing can obtain good efficiency and accuracy.

A Merged-System-Status Monitoring Mechanism in NPP Digital Control System

Yang Xiaohua, Liu Chaohui, Chen Zhi, Liu Jie, Wu Zhiqiang

2014, 35(3): 138-141. doi: 10.13832/j.jnpe.2014.03.0138

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The digital control system has been wildly applied in nuclear power plant. Being the key safety component in system, Software may lead to software failure and dysfunctional interactions among software and hardware components. The current hardware status monitoring mechanism can’t deal with this new failure mode in a perfect way. This paper applied the STAMP to analysis the failure mode in NPP digital system firstly, take the software, hardware and the interactions as research objects, and propose a new system merged-status monitoring mechanism at last which considers that all status information include software, hardware and the interactions. This mechanism can provide the ability for precaution and a diversity way for system monitoring. It was meaningful for digital control system in nuclear power plant.

Improved Design of Shield Transfer Container for Cement Solidified Radioactive Waste

Kong Jingsong, Guo Weiqun

2014, 35(3): 142-144. doi: 10.13832/j.jnpe.2014.03.0142

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The shield transfer container is one of the necessities in the hoisting and transportation of the radioactive solid waste. During the operation, because of the dislocation of electromagnetic sling or cable winded, failures often occur. To improve the safety and reliability, this paper designs the devices to centre the electromagnetic sling, and prevent the twisting, and video monitoring.

Technical Study on Separating Compounds of Low Level Radioactive Wastewater by Composite Membranes

Kong Jingsong, Guo Weiqun

2014, 35(3): 145-147. doi: 10.13832/j.jnpe.2014.03.0145

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In the view of low level radioactive wastewater from operation and decommissioning project for the nuclear facilities and technology of reverse osmosis, this paper analyzes the related research of reverse osmosis technology at home and aboard, and designs a technical system in practice by using reverse osmosis combined with a pretreatment process of disc filtration-ultrafiltration or filtration-microfiltration to treat radioactive wastewater.

Building and Application of Radiation Monitoring Model for Radioactive Waste Treatment Installation

Kong Jingsong, Guo Weiqun

2014, 35(3): 148-151. doi: 10.13832/j.jnpe.2014.03.0148

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In this paper, the general block frame of a radiation monitoring model for radioactive waste treatment installation is presented, and the devices, methods, management objectives, and measurement frequency are detailed. Various measurement data of radioactive waste treatment from this model is analyzed, and the results validate the feasibility and scientific value of the model.

Convergence Study on Neutronic/Thermohydraulic Coupling Based on Fixed Point Theory

Liu Shichang, Cai Jiejin

2014, 35(3): 152-157. doi: 10.13832/j.jnpe.2014.03.0152

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The traditional iterative method is not applicable for some new reactors（such as supercritical water-cooled reactor） which have intense neutronic/thermohydraulic coupling（N-T coupling） behavior. The mathematical model of N-T coupling based on fixed point theory is established in this paper, with the calculation examples of SCWR, so as to present the convergence analysis of iterative methods in N-T coupling. The convergent criterion of N-T coupling is proposed, which can show the real-time convergence situation of iteration. Moreover, the self-adaptive relaxation factor and corresponding algorithm were introduced.

Analysis of Impact of Mixing Flow on the Pebble Bed High Temperature Reactor

Hao Chen, Li Fu, Guo Jiong

2014, 35(3): 158-161. doi: 10.13832/j.jnpe.2014.03.0158

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The impact of the mixing flow in the pebble flow on pebble bed high temperature gas cooled reactor（HTR） was analyzed in the paper. New code package MFVSOP which can simulate the mixing flow was developed. The equilibrium core of HTR-PM was selected as reference case, the impact of the mixing flow on the core parameters such as core power peak factor, power distribution was analyzed with different degree of mixing flow, and uncertainty analysis was carried out. Numerical results showed that the mixing flow had little impact on key parameters of pebble bed HTR, and the multiple-pass-operation-mode in pebble bed HTR can reduce the uncertainty arouse from the mixing flow.

Corrosion Behavior of MA956 in Supercritical Water

SHen Chao, Pan Xiangfeng, Zhu Fawen, Zhang Lefu

2014, 35(3): 162-166. doi: 10.13832/j.jnpe.2014.03.0162

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The corrosion behavior of MA956 in SCW at 550/600/650 was studied. The℃ morphology, structure and elements distribution of oxide film was studied through SEM, EDS and XPS. The weight gain results of 1000 h immersion in SCW shows that MA956 exhibits excellent resistance to corrosion and the surface film is single layer, rich in Al but poor in Fe. A large amount of Al2O3 has been observed on the surface film at temperature of or above 600℃, and the size reaches to 8 μm at 650℃. Meanwhile, the pre-oxidized MA956 has even higher corrosion resistance. The surfaces of the speciments are smooth and intact and no pitting is observed after exposure for 1000 h in SCW.

Determination of Elements in Stainless Steel by X-Ray Fluorescence Spectrometry

LÜ Pingping, an Shenping

2014, 35(3): 167-169. doi: 10.13832/j.jnpe.2014.03.0167

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Various elements in stainless steel have been measured by X-ray fluorescence spectrometry. Spectral overlap and matrix effect of interference elements have been corrected by interfering. The precision and comparative tests show that the precision of the method（RSD） is less than 1% for the main portions of elements（Cr, Ni, Si, Mn, Ti, Mo, W）, and the precision of the method（RSD） is less than 12% for the trace elements（Al, Cu, Co, Sn）.

Study on Application of RCM in Haiyang NPP

Zou Weixiang, Zou Jiamao

2014, 35(3): 170-172. doi: 10.13832/j.jnpe.2014.03.0170

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The paper introduces the application status of the Reliability-Centered Maintenance（RCM） technology in Haiyang nuclear power plant, and analyzes the RCM application in the future, including the optimization of equipment reliability classification, development of performance monitoring program and preventive maintenance program, optimization of preventive maintenance program, risk significant components management and optimization of spare parts. The application of RCM can help utility to develop integral equipment maintenance strategy, improve the equipment reliability and availability, and reduce maintenance costs.

Development of a Dynamic Simulation Program of AP1000 Reactor Core

Liu Yang, Wang Zhao, Kuang Hongbo, Bu Jiangtao, Zhao Fuyu

2014, 35(3): 173-176. doi: 10.13832/j.jnpe.2014.03.0173

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Abstract:
The AP1000 adopts the advanced Mechanical Shim（MSHIM） core control strategy to control the reactor power and axial power distribution. This paper presents the development of a dynamic simulation program of AP1000 reactor core in Matlab/Simulink. Firstly, an optimum nodal core model is developed, which both has satisfactory accuracy and fast simulation speed. Then, the MSHIM control system is established. Based on the simulation program, the typical load follow simulation is performed. The correctness of the program is preliminary validated by comparing the simulation results with the references.

2014 Vol. 35, No. 3