核动力工程

Research on Calculation Method for Successive Layer Coupling Core Power Distribution Expanding

Li Songling, Qin Dong, GuanHui, Wu Lei, Xia Bangyang

2015, 36(2): 1-5. doi: 10.13832/j.jnpe.2015.02.0001

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Abstract:
This paper introduces the theoretic model for the successive layer coupling method for the core power distribution expanding and the solution method for the successive over relaxation equation. The calculation code EXP for the core power distribution expanding, which is based on these methods, has been programmed in FORTRAN90 computer language. The theoretic and metrical data of the unit 1, cycle 11 of Daya Bay NPP are used for analyzing the sensitivity and validity of the expanding calculation results. The results show that, this expanding method uses the theoretic data to build the coupling connection of assemblies in the core and uses the metrical data to calculate the power of all assemblies, and then the expanding calculation is conducted. The method is correct and effective, and has a good adaptability for the invalidation of the measure points.

Research on Calculation Code PICM for Plate-Type Fuel Assembly Few Group Parameter

Yin Qiang, Wang Jiachong, Lu Wei

2015, 36(2): 6-8. doi: 10.13832/j.jnpe.2015.02.0006

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In order to solve the calculation problems for the plate-type fuel assembly few group parameter, the establishment of geometry configuration, the calculation of resonance of the fuel plate and the neutron transportation, and the whole calculation process are studied, and the calculation code PICM for the plate-type fuel assembly is established. IAEA benchmark problems are adopted to verify the PICM. The results indicated that PICM can accurately calculate the few group parameter for the plate-type fuel assembly.

Calculation of HTR-10 First Criticality with MVP

Xie Jiachun, Yao Lianying

2015, 36(2): 9-12. doi: 10.13832/j.jnpe.2015.02.0009

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The first criticality of 10 MW pebble-bed high temperature gas-cooled reactor-test module（HTR-10） was calculated with MVP. According to the characteristics of HTR-10, the Statistical Geometry Model of MVP was employed to describe the random arrangement of coated fuel particles in the fuel pebbles and the random distribution of the fuel and dummy pebbles in the core. Compared with previous results from VSOP and MCNP, the MVP results with JENDL-3.3 library were little more different, but the results with ENDF/B-Ⅵ.8 library were very close. The relative errors were less than 0.7%, compared with the first criticality experimental results. The study shows that MVP could be used in the physics calculations for pebble bed high temperature gas-cooled reactors.

Study on Dynamic Rod Worth Measurement Method and Its Test Verification

Wu Lei, Liu Tongxian, ZHao Wenbo, Li Songling, Yu Yingrui

2015, 36(2): 13-16. doi: 10.13832/j.jnpe.2015.02.0013

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Abstract:
An advanced rod worth mesurement technique, the dynamic rod worth measurement method（DRWM）has been developed. Static Spatial Factors（SSF） and Dynamic Spatial Factor（DSF） were introduced to improve the inverse kinetics method. The three dimensional steady and transient simulations for the mesurement process was carried out to calculate the modifacation factors. The rod worth measurement test was performed on a research reactor to verify DRWM. The results showed that the DRWM method provided the improved accuracy and could be a replacement of the traditional methods.

²³⁸Pu Irradiation and Fabrication

Sun Shouhua, Zhou Chunlin, Li Ziyan, Wang Hao

2015, 36(2): 17-20. doi: 10.13832/j.jnpe.2015.02.0017

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In the paper, the production procedures and physics basics for ²³⁸Pu are introduced. Irradiation production processes such as design of ²³⁷Np target rod, target rod load capacity of ²³⁷Np and ²³⁸Pu yield of calculation are presented. Furthermore, the post-irradiation technical procedures including chemical separating, purifying, recycling, ²³⁸Pu powder acquirement and heat source fabrication, are also summarized with cautious.

Effect of Rayleigh Damping on Result of Large Mass Direct Integration Method

Huang Bingchen, Shen Wei, Lu Zhi

2015, 36(2): 21-23. doi: 10.13832/j.jnpe.2015.02.0021

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Additional Rayleigh damping load will be applied on the large mass points and smaller calculation results would be resulted when the direct integration method is adopted to conduct the excitation on large mass points.. This paper explains the reason of the additional Rayleigh damping load, and gives the solution. Numerical results show that the method can be applied in the engineering calculation.

Estimation of Measurement Uncertainties for Subcooling Margin of Coolant at Core Outlet in CPR1000 NPPs

Wang Zhenying, Sun Chen, Wu Bei

2015, 36(2): 24-27. doi: 10.13832/j.jnpe.2015.02.0024

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Abstract:
The core cooling and monitoring system（CCMS） is installed in CPR1000 nuclear power plants to measure the subcooling margin of the coolant at the core outlet. Every error origin in the process of the measurement was investigated in this paper. The uncertainties of the subcooling margin measurement was estimated in saturation condition for the case of the distribution of the coolant temperature at the core outlet is heterogeneous or homogeneous, and the curves of uncertainty interval boundaries changing with primary pressure were obtained, based on which the method for determination of the error（ε） curve of the subcooling margin measurement which is used in CCMS to diagnose the cooling state of the core is developed. The acquired results have been practically implemented in CPR1000 nuclear power plants.

Research on Resistance Features of a 5×5 Rod Bundle with Spacer Grid

Li Quan, Chen Jie, Jiao Yongjun, Yu Junchong, Chen Ping, Lei Tao, Ru Jun

2015, 36(2): 28-32. doi: 10.13832/j.jnpe.2015.02.0028

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Abstract:
Numerical technology is used to study the resistance performance of a 5×5 fuel rod bundle with spacer grid. In the progress of spacer grid’s CFD evaluation, we decrease the heights of springs and dimples to leave a small gap between springs, dimples and fuel rods as many researchers do. We use this kind of simplified geometry model to perform numerical simulations, finding that the local loss coefficient calculated is conspicuously smaller than experiments. We improve the geometry model after analyzing the causes and use different turbulence models to simulate the flow, finding that the results got by SST model match the best with that from experiments. We also split the spacer grid into two parts, to model the mixing vanes and other parts separately. The results indicate that the local loss coefficient of mixing vanes takes a little proportion of the total spacer grid. However, the cross-flow initiated by mixing vanes will increase the resistance loss downstream the spacer grid.

AP1000 DNBR Calculation and Analysis of Complete Loss of Flow Accident

Huang Shuliang, Feng Jinjun, Chen Qiaoyan, Xiao Hong

2015, 36(2): 33-36. doi: 10.13832/j.jnpe.2015.02.0033

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Abstract:
The accident of complete loss of forced reactor coolant flow in AP1000 plant may cause the phenomenon of departure from nucleate boiling（DNB） in the reactor core. This paper uses the TRACE code of US NRC and FLICA Ⅲ-F sub-channel code of France to establish the model of the AP1000 reactor system and core, and uses the transient parameters given by the code of TRACE as the input parameters of FLICA Ⅲ-F, and calculates and analyzes the transient DNB of complete loss of flow accident. The calculate result shows that in the transient the DNBR value in the reactor core is always higher than the safety analysis limit, thus it satisfies the DNB design criterion. By comparing the result with the value from the safety analysis report, it demonstrates that the system and DNB analysis model by TRACE and FLICA Ⅲ-F code in this paper is reasonable which is available in the AP1000 project design.

Study on General Expression for Liquid Force Per Unit Mass under Non-Inertial Reference Frame

Zhou Lei, Ge Chao, Zan Yuanfeng, Yan Xiao, Chen Bingde

2015, 36(2): 37-41. doi: 10.13832/j.jnpe.2015.02.0037

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Thermal hydraulic problems under motion conditions are usually studied in non-inertial reference frames for convenience, which results in the necessity of gravity vector transformation and additional forces calculation. Based on the strict mathematical deductions, the transformation matrix of orthogonal coordinates for 3 dimensional rotating has been derived and the general expression for liquid force per unit mass under non-inertial reference frame was obtained in this paper. Forces under various typical ocean moving conditions were also calculated and discussed for application purpose. This paper provides a useful reference for thermal hydraulic researches under motion conditions.

Research on Wall-to-Vapor Convective Heat Transfer Model in Reflooding Phase of Typical PWR Based on RELAP5

LÜ Li, Yu Tao, Yu Hongxing, Wu Dan, Xie Jinsen, Peng Huanhuan

2015, 36(2): 42-45. doi: 10.13832/j.jnpe.2015.02.0042

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This paper evaluates the rationality of RELAP5 reflood models based on the reflooding experiments FLECHT SEASET. The calculated results show that the current version of RELAP5 underestimates the peak clad temperature when simulating the low flooding rate test. Combined the characteristics of the reflooding phase of typical PWR and considered the vapor flow state and rod bundle configuration effects, the wall-to-vapor convective heat transfer model is modified. A new wall-to-vapor convective heat transfer model is established for the simulation of the typical PWR reflooding phase. Through the validation of this new model by comparing the calculation results of peak clad temperature from original code and modified code, it can be concluded that the new model is reasonable.

Pre-Oxidation Treatment and Densification Mechanism for Low Temperature Sintering of UO_2+x Pellets

Li Rui, Sun Maozhou, Nie Lihong

2015, 36(2): 46-50. doi: 10.13832/j.jnpe.2015.02.0046

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In this paper, for the goal of sintering the uranium dioxide pellet in low temperature, UO₂ powder was surface pre-oxidation treated by thermal analyzer, then the transformation point, specific area, phase component and microstructure of powder were studied by specialized instruments. The results show that there is a little of U₃O₇ in uranium dioxide powders by pre-oxidation treatment at 240℃ for 8h in air, and UO₂ powders will transform into U₃O₈ at 382℃for 8h in air. The simulation sintering of UO_2+x pellet was launched by the thermal dilatometer. Shrinkage temperature of the uranium dioxide pellets after pre-oxidation treatment decreased from 1200 ℃ to 580 ℃, and the densification rate（ΔL/L） increased also from 1.52×10^-4/K to 3.08×10^-4/K. The mechanism of low temperature sintering to pre-oxidation UO_2+x pellets was explained by the simplified point defect model and densification equation. The UO_2+x diffusion coefficient is much higher than that of UO₂. The densification factor A is positive correlation to UO_2+x diffusion coefficient,and it could be expressed by aquadratic polynomial according to temperature T, which factor a=16.23658,b=0.04247,c=-2.18802×10^-5.

Study on HBI Method for Freezing Process of Overheat Melt

Zhang Zhuohua, Yu Junchong, Peng Shinian

2015, 36(2): 51-54. doi: 10.13832/j.jnpe.2015.02.0051

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Relative errors between results from different HBI methods under different conditions and analytical solution are compared and analyzed in this paper. Quadratic approximation is chosen for the calculations of freezing process of overheat melt on cold structure by comparison results of relative errors. HBI under quasi-steady state is applied in this paper and results suit well with numerical results.

Development of Detection System for Fuel Element Cladding Damage Based on ¹³⁷Cs and ⁸⁵Kr Nuclides

Xie Bo, Ceng Yong, Zhang Hongxiang

2015, 36(2): 55-57. doi: 10.13832/j.jnpe.2015.02.0055

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A detect system was developed for the fuel elements with shutdown of more than 4 months and that can not be taken out from water and tested for the damage of fuel element cladding. The high temperature water is used by the system to heat the fuel element to release the radionuclide, and pressure changes are applied to accelerate the radionuclide release, and then the content of ¹³⁷Cs and ⁸⁵Kr is collected and detected to determine whether the fuel element is damaged. The results show that the system can conduct the damage detection of fuel element cladding without taking the fuel out from water, and has the characteristics of convenient, fast and accurate.

Calculation and Experimental Verification of Shielding Composites against High-Speed Neutrons Attenuation

Yang Wenfeng, Wu Xiaoyong, Liu Ying

2015, 36(2): 58-61. doi: 10.13832/j.jnpe.2015.02.0058

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Based on the test method and theory of the removal cross section, the macro and micro removal cross sections of 4 different composites and relative elements have been calculated, and experimentally verified by the relaxation length and transitivity percent. The results indicate that, the tested transitivity values for 4 different composite plates（20 mm） are all 10% higher than those of calculated, which validate the availability and practicability of removal cross section used in the neutron shielding calculation. Finally, the differences and influential factors of calculated values and test values have been analyzed in detail.

Analysis of Blackout Accident and Mitigation Measure for Small Reactors

Chen Hang, Zhang Fan, Yan Feng, Wang Kun

2015, 36(2): 62-65. doi: 10.13832/j.jnpe.2015.02.0062

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Based on the typical small reactors, the blackout accident sequence in small reactors under full power operation is calculated by the MELCOR, and the effect of mitigation measures is analyzed and compared in the paper. The results show that when losing the whole electrical source, the reactor loses the thermal trap and the high-pressure CMAs happens, and the integrity of small reactor is destroyed. If the emergency electrical source can be supplied in time, safety injection can be function, the recycle period which used sea water can cool the reactor and mitigate the accident process effectively.

Functional Design for Online Automatic Test of Response Time in Protection and Measurement Channels

Li Hongxia, huo Yujia, Chen Jing, Yu Junhui, Zhu Jialiang

2015, 36(2): 66-67. doi: 10.13832/j.jnpe.2015.02.0066

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The function for the automatic test of the response time in the protection and measurement channels is designed by "double contact" and "fast collection" methods and applied to the periodic test of QINSHAN phase II extension project. Test and operation results show that the design satisfies the requirement of the nuclear power plant, with simple and convenient operation, high reliability and good performance.

Survivability Assessment of Instruments for Sever Accident

Yu Junhui, Wang Yuanbing, Li Liang, Li Hongxia, huo Yujia, Chen Jing

2015, 36(2): 68-71. doi: 10.13832/j.jnpe.2014.02.0068

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Firstly the related international and domestic standards, laws and regulations were studied, to identify the top requirements on the survivability assessment of the instruments. Secondly an assessment method of curve comparison and integrated assessment procedure were provided based on the definition of 5 key assessment factors. The proposed analysis methods can be used to assess reliably the availability of the instruments, to effectively improve its ability of handling the severe accidents. In the end, this paper analyzed the existing assessment issues in China and put forward the corresponding technical opinions.

Design of Digital Nuclear Instrumentation System of Fuqing Phase I NPP

Wang Yinli, Luo Wei, Zhu Pan, Li Yanrong, Zhu Hongliang, Yang Daibo

2015, 36(2): 72-76. doi: 10.13832/j.jnpe.2015.02.0072

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Nuclear instrumentation system（RPN） is an important part of instrument and control system in NPPs. This paper introduces the general architecture, functions, design demands and design characteristics of the digital nuclear instrumentation system in Fuqing phase I project, and also the functional distribution between RPN and safety digital instrument ＆ control system is compared with that of Ling’ao phase II NPP. The result shows the digital RPN design of Fuqing phase I project satisfies the system functional demands, and can be used as an reference for optimizing RPN design of the following projects.

Study on Reactor Coolant Temperature Channel Calibration Test in Digital Control Nuclear Power Plants

huo Yujia, Li Hongxia, Li Liang, Chen Jing, Li Xiaofen, Zhu Jialiang

2015, 36(2): 77-80. doi: 10.13832/j.jnpe.2015.02.0077

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The paper introduces the content of the TP RCP63 test simply, and analyzes the effect on the test due to the abroad application of digital control systems. Furthermore, the paper emphasizes the study of the difference and corresponding problems in the test comparing with the nuclear power plants with the analogue technology. As to the problems, the corresponding design solution are provided for the temperature difference, the coefficient of average temperature summer and the temperature signals calibration in TP RCP63 test of the digital nuclear power plants.

Development of Automatic Ultrasonic Inspection System for Heavy Water Reactor Feeder Pipe

He Ziang, Shang Junmin, YuanJianzhong, Wang Shicun, He Hai, Xu Kui

2015, 36(2): 81-83. doi: 10.13832/j.jnpe.2015.02.0081

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A set of automatic ultrasonic inspection system for CANDU PHWR Feeder pipe is developed. The phased array ultrasonic inspection function is achieved using the normal ultrasonic probe. This system can carry out the automatic data acquire on site, and remotely conduct the real time data analysis, with the inspection accuracy ±0.03 mm. A set of auxiliary shield equipment is also developed, which shield rate is up to 80%.

Discussion about Relation between “A” Type EOP for PWR and Emergency Classification Level

Yu Hong, CHeng Shisi

2015, 36(2): 84-88. doi: 10.13832/j.jnpe.2015.02.0084

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The EOP for the first reactor of Fangjiashan Nuclear Power Plant is taken as an example in this paper. The indications and the parameters in the EOP are compared with the EAL in NEI 99-01 to discuss which emergency classification level the plant should be into when the "A" type EOP is implemented. Developing the EAL, the indications and the parameters should be taken into account.

Improvement and Optimization for In-service Inspection of M310 Nuclear Power Station

Wang Chen, Sun Haitao, Gao Chen, Deng Dong

2015, 36(2): 89-92. doi: 10.13832/j.jnpe.2015.02.0089

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In-service inspection（ISI） is an important method to ensure the safety of the mechanical equipments in nuclear power stations. According to the in-service inspection experience feedback from the domestic nuclear power stations, the reasonableness of some provisions in the RSE-M code are discussed and the applications of risk-informed in-service inspection（RI-ISI）are introduced, and the advices for the optimization of the ISI of the domestic M310 nuclear power stations are proposed.

Method to Improve Measurement Accuracy for Bypass Temperature of Reactor Coolant System in Nuclear Power Plants

Chen Jing, Chen Ke, huo Yujia, Li Hongxia, Yu Junhui, Li Xiaofen

2015, 36(2): 93-95. doi: 10.13832/j.jnpe.2015.02.0093

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In order to improve the accuracy of the temperature measurement in bypass of the reactor coolant system in nuclear power plants, MATLAB optimization toolbox Lsqnonlin function by the nonlinear least square method is used to make a nonlinear curve fitting to build the relational function of resistance-temperature. Calculate and analysis the deviation between the temperature value through the relational function and the measurement value of the standard thermometer. Results show that the relational function of resistance-temperature established by the nonlinear least square method can improve the accuracy of the temperature measurement throughout the whole measurement range for one order of magnitude.

Design of Periodic Test for Reactor Protection System of Hongyanhe NPP

Zhu Pan, Wang Yinli, Feng Wei, Li Xiejin, Zhou Jixiang, Luo Wei, Yu Yun

2015, 36(2): 96-100. doi: 10.13832/j.jnpe.2015.02.0096

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Reactor protection system of Hongyanhe project is based on Mitsubishi MELTAC safety digital platform. This paper introduces the scope and principle for periodic tests of reactor protection system, and then it describes the design schemes of instrumentation channel test, protection logic test and actuator control channel tests in detail, finally it analyzes the characteristics of the tests. The result shows that the periodic test solutions of reactor protection system for Hongyanhe project adequately utilize the advantages of automatic tester, and the test scope is extended and the test availability, flexibility and facility are enhanced.

Preliminary Study on MSHIM Strategy in M310 Unit NPP

Wang Jinghui, Wang Jinyu, Wang Dan

2015, 36(2): 101-104. doi: 10.13832/j.jnpe.2015.02.0101

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Taking the Daya Bay nuclear power plant as a research target, this paper applies the MSHIM strategy on the M310 unit. M310 unit could operate with MSHIM strategy under various modes of operation, including base load and load follow. But the ability of banks of G1, G2, G3 and R is insufficient during load follow. After the redesign of the rod cluster control assembly pattern, the analysis indicates that it is possible to implement the MSHIM strategy on M310 unit with the current placement of control rods.

Evaluation of Thermal Ageing of RCP 90° Elbow for Nuclear Power Plants

Huang Junlin, Liu Xianghong, Huang Bingyan

2015, 36(2): 105-108. doi: 10.13832/j.jnpe.2015.02.0105

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Impact and fracture toughness properties of the reactor coolant piping（RCP） 90°elbow made by static cast austenitic-ferritic（duplex） stainless steels for Qinshan phase II extension project are evaluated, after long time ageing and 10 years’ service at 325℃, according to the methods and procedures from IAEA and other international literatures. The evaluation results indicate that: the impact and fracture toughness properties of the elbow decrease obviously after 10years’ service at 325℃, but the impact properties remain in the safe range; after long time ageing, the impact value can not satisfy the design requirement anymore.

Analysis and Processing of Main Bolt Gluing in RPV

Nie Zhiping, Wang Nianwei, Dong Wanfu

2015, 36(2): 109-112. doi: 10.13832/j.jnpe.2015.02.0109

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Based on the structure and its condition of the main bolt of RPV, this paper puts forward a kind of clipping peak and averaging load structure of the thread, which can equal the load distribution of thread connection.Meanwhile, the mathematical model of bigbolt thread Connection is set up. By using the finite element analysis function, Compare with ordinary screw thread the feasibility of averaging load structure of the thread is validated. This thread structure can eliminates the main bolt gluing and improves the safety, reliability and longer life of the thread connection for the RPV.

Study on Collaborative Optimization Control of Ventilation and Radon Reduction System Based on Multi-Agent Technology

Dai Jianyong, Meng Lingcong, Zou Shuliang

2015, 36(2): 113-115. doi: 10.13832/j.jnpe.2015.02.0113

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According to the radioactive safety features such as radon and its progeny, combined with the theory of ventilation system, structure of multi-agent system for ventilation and radon reduction system is constructed with the application of multi agent technology. The function attribute of the key agent and the connection between the nodes in the multi-agent system are analyzed to establish the distributed autonomous logic structure and negotiation mechanism of multi agent system of ventilation and radon reduction system, and thus to implement the coordination optimization control of the multi-agent system. The example analysis shows that the system structure of the multi-agent system of ventilation and reducing radon system and its collaborative mechanism can improve and optimize the radioactive pollutants control, which provides a theoretical basis and important application prospect.

Analysis of Operation Events for HFETR Emergency Diesel Generator Set

Li Zhiqiang, Ji Xifang, Deng Hong

2015, 36(2): 116-118. doi: 10.13832/j.jnpe.2015.02.0116

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By the statistic analysis of the historical failure data of the emergency diesel generator set, the specific mode, the attribute, and the direct and root origin for each failure are reviewed and summarized. Considering the current status of the emergency diesel generator set, the preventive measures and solutions in terms of operation, handling and maintenance are proposed, and the potential events for the emergency diesel generator set are analyzed.

Analysis of Suitability in Application of RCC-M

Gu Jian, Li Jianli, Jiang Yu

2015, 36(2): 119-121. doi: 10.13832/j.jnpe.2015.02.0119

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In the practices of the nuclear power plant construction, unpractical prescriptions in equipment technical specification will result in much more unnecessary non-conformance items which meet RCC-M., Based on the engineering experience, this paper proposed three moderate application principles from three aspects, which can more specifically regulate the behavior of the people in this field to some extent.

Dynamic Model and Analyses of Supercritical Steam Generator of High Temperature Gas-Cooled Reactor

Liu Dan, Sun Jun, Sun Yuliang

2015, 36(2): 122-126. doi: 10.13832/j.jnpe.2015.02.0122

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According to the characteristics of steam generator operating under supercritical pressure, the model of supercritical once-through steam generator consisted of helical coils used in HTGR was improved to study the dynamic characteristics of the supercritical steam generator, based on the optimized model and heat characteristics analyses in steady state conditions. Two scenarios, the helium flow rate jump and successive jumps of helium and water flow rates, were simulated to analyze the dynamic responses of various temperatures and heat transfer parameters. The simulation results indicated that the helium flow rate step change had influence on both primary and secondary side parameters. Yet, the secondary side parameters changed more slowly due to the delay effect caused by large heat capacity of metal and water. In the test of successive jumps of helium and water flow rates, some parameters had slight fluctuation, which was attributed to the heat transfer characteristics of supercritical water.

Design and Verification of Integrated Measurement Instrument for NPP Spent Fuel Pool

Sun Yihui, Xie Jingjing, Wu Xueqiong, Wen Ji, Sun Lin

2015, 36(2): 127-129. doi: 10.13832/j.jnpe.2015.02.0127

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The design of an innovative and integrated instrument device for level and temperature measurement in the spent fuel pool of nuclear power plants has been proposed based on the environment and functional requirement of spent fuel pool. The validation of the prototype device has been implemented and it is demonstrated that the accuracy and response meet the specifications for the spent fuel pool monitoring, with enhanced capability to monitor the level and temperature even under the station blackout accident.

Application of Metal Bobbin Coil in Control Rod Drive Mechanism

Yu Jie, Chen Fengzu

2015, 36(2): 130-133. doi: 10.13832/j.jnpe.2015.02.0130

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This Paper compared the performance of CRDM using metal bobbin coils with those using the traditional non-metal bobbin. From the test result, CRDMs with both kinds of coils can carry out their function correctly and all parameters are well within the specification. But metal bobbin has many advantages over non-metal bobbin, such as higher temperature endurance, radiation resistant, aseismatic performance, mechanical strength and machinability, and lower cost. Using the metal bobbin, coils with temperature index of 420℃ or above can be built and the goal to eliminate the cooling system on top of the reactor can be achieved.

Discussion for Related Issues of Nuclear Safety Lead Storage Batteries Equipment Qualification

Wu Qi, Ren Lihua, Lang Aiguo, Li Shixin

2015, 36(2): 134-137. doi: 10.13832/j.jnpe.2014.02.0134

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The qualification test sequence and conditions, components replacement during the accelerated aging test, and capacity test on the aging of nuclear safety lead storage batteries are discussed in this paper. Considering the class 1E cable qualification practices at home and abroad, this paper proposes some points and technical positions related to the three mentioned issues.

Research on Performance of Gas Methyl Iodide Removal in Bubble Column Reactor

Zhou Yanmin, Sun Zhongning, Gu Haifeng, Wang Junlong

2015, 36(2): 138-142. doi: 10.13832/j.jnpe.2015.02.0138

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Based on the removal of gas methyl iodide by containment filter venting system, the alkalescent sodium thiosulphate solution was used as the absorber to study the characteristics of the absorption process with experiments. The results show that the temperature of solution, system pressure, gas flow rate and the height of liquid are important factors to influence the gas methyl iodide removal efficiency. The influence of temperature present a regional effect, in the range of 0~80℃, the removal efficiency increases obviously along with the improved temperature, while the chemical reaction process is a major factor that limiting the removal efficiency. When the temperature is higher than 80℃, the efficiency is no longer sensitive to the variation of temperature and the mass transfer process becomes the main limiting factors. The increase of system pressure or height of solution can enhance the gas absorption process significantly, and the removal efficiency improves linearly with two parameters. However, the gas volume flow rate plays an opposite role on the absorption process. In addition, the variation of entrance concentration has a little impact on the removal efficiency.

Preliminary Evaluation of RELAP5 for Design of Secondary Side Passive Residual Heat Removal System

Xiong Wanyu, Gong Houjun, Xi Zhao, Zhuo Wenbin, Huang Yanping

2015, 36(2): 143-146. doi: 10.13832/j.jnpe.2015.02.0143

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In this paper, preliminary evaluation of RELAP5 code was made on its application to the design of second side passive residual heat removal system（PRHR） by comparing to the experimental data. Because the theoretical basis of RELAP5 code was one-dimensional flow hypothesis, RELAP5 code was inadequate in the simulation of natural convection heat transfer in accident cooling pool during the initial stage of PRHR. In later-period of PRHR, the heat transfer mode in accident cooling pool was nucleate boiling based, and pool boiling had absolute predominance in the heat transfer quality, and the calculation results fitted the experimental data quite well. RELAP5 code can be basically applied to the steady state performance analysis of second side passive residual heat removal system.

Investigation on Flow-Induced Vibration Mechanism of Fuel Rods Fixed by Wrapped Wire

Wu Licun, Lu Daogang, Liu Yu, ZHong Haoliang, Liu Guangyao

2015, 36(2): 147-150. doi: 10.13832/j.jnpe.2015.02.0147

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The flow-induced vibration mechanism of the fuel rod fixed by wrapped wire under the influence of leakage flow is investigated by the way of experiment and numerical simulation. According to the CFD and experimental results, it is found that the wrapped wire would play a role of increasing the cross flow mixing effect in the flow channel, which would have a significant influence on the stability of fuel rod. Based on experimental and numerical results, it is found that when flow rate is low, the vibration of rods is mainly caused by the turbulence, but as flow rate increases, the effects of leakage flow become obvious. Effect of vibration leakage flow of the fuel rods are divided into two kinds: changing the vibration energy distribution in the frequency domain, so that the high frequency energy of vibration is increased; increasing the RMS value of vibration displacement of fuel rod.

Effect of Rolling Motion on Liquid-Vapor Interface Area Parameter in A Narrow Channel

Li Shaodan, Tan Sichao, Gao Puzhen, Xu Chao

2015, 36(2): 151-154. doi: 10.13832/j.jnpe.2015.02.0151

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The subcooled flow boiling in a narrow rectangular channel under rolling motion was experimentally studied. The variation of interfacial parameters were obtained by adopting the digital image processing technology, such as the void fraction and the interfacial area concentration. The experimental results showed that these interfacial parameters in the narrow channel were periodically fluctuated due to the effect of rolling motion, and the period was identical with that of rolling motion. The fluctuation of the void fraction and interfacial area concentration under rolling motion was mainly affected by the variation of bubble equivalent diameter.

Study on Numerical Simulation for Sealing Behavior of C-Ring

Dong Yuanyuan, Luo Ying, Zhang Liping

2015, 36(2): 155-159. doi: 10.13832/j.jnpe.2014.02.0155

Abstract(9) PDF(0)

Abstract:
In this paper, a relatively authentic three-dimensional finite element model of C-ring is established. The sealing behavior of C-ring is simulated by ANSYS while the coupling of elastoplasticity and contact is taken into consideration. With the numerical simulation, the compression-springback characteristic curve of C-ring is obtained. As the characteristic curves are coincident with test results, the validity of the numerical simulation method is confirmed. In the compression state, the stress in the spring is higher at the 0°, 90°,180° and 270° regions. In the springback state, the linings will warp to make the gap of linings be wider. The interaction of each part of C-ring will influence the sealing behavior obviously.

Study on Analysis Method for Two Phase Discharge Force

Wu Dan, Fu Ran, Wang Yanping, Yu Hongxing

2015, 36(2): 160-164. doi: 10.13832/j.jnpe.2015.02.0160

Abstract(10) PDF(0)

Abstract:
In this paper, a set of analysis methods for discharge force calculation is established. Taking the discharge line of the typical PWR NPP as an example, the discharge force subjected by the downstream line of the pressurizer safety valve is calculated, with the presence of water seal. The calculation results are consistent with the reference data provided by FRAMATOM, which indicates that the proposed method is correct.

Void Fraction Measurement in Vertical Slug Flow

Wu Xiangxiang, Huang Shanfang, Bai Su, Li Zhongchun, Li Songyu, Zhou Linglan, Jiang Guangming

2015, 36(2): 165-167. doi: 10.13832/j.jnpe.2014.02.0165

Abstract(13) PDF(0)

Abstract:
A double-tip needle-contact capacitance probe is proposed to measure the void fraction as well as the bubble velocity of the slug flow in the vertical air-water two-phase flows. The working principle of this probe is derived by theoretical analyses, and then dynamic experiments are performed to acquire the signals of slug flow. The results show that the new probe works stably and reliably and that the probe is independent of the water salinity. Signals of slug flow detected by the needle-contact capacitance probe are consistent with the actual flow structure. The measured void fraction is α=37.5% and the bubble velocity is v=0.545 m/s.

2015 Vol. 36, No. 2