Performance analysis of automatic depressurization system in advanced PWR during a typical SBLOCA transient using MIDAC

Sun, Hongping,Zhang, Yapei,Tian, Wenxi,Qiu, Suizheng,Su, Guanghui Korean Nuclear Society 2020 Nuclear Engineering and Technology Vol.52 No.5

The aim in the present work is to simulate accident scenarios of AP1000 during the small-break loss-of-coolant accident (SBLOCA) and investigate the performance and behavior of automatic depressurization system (ADS) during accidents by using MIDAC (The Module In-vessel Degradation severe accident Analysis Code). Four types of accidents with different hypothetical conditions were analyzed in this study. The impact on the thermal-hydraulic of the reactor coolant system (RCS), the passive core cooling system and core degradation was researched by comparing these types. The results show that the RCS depressurization becomes faster, the core makeup tanks (CMT) and accumulators (ACC) are activated earlier and the effect of gravity water injection is more obvious along with more ADS valves open. The open of the only ADS1-3 can't stop the core degradation on the basis of the first type of the accident. The open of ADS1-3 has a great impact on the injection time of ACC and CMT. The core can remain intact for a long time and the core degradation can be prevent by the open of ADS-4. The all results are significant and meaningful to understand the performance and behavior of the ADS during the typical SBLOCA.

Repair Decision Based on Sensitivity Analysis for Aero-Engine Assembly

Yanhui Sun,Junkang Guo,Jun Hong,Guanghui Liu,Wenwu Wu,Cong Yue 한국정밀공학회 2019 International Journal of Precision Engineering and Vol.20 No.3

Strict requirements for concentricity of the multistage high pressure rotor of an aero-engine are employed to guarantee performances such as vibration. Tedious and time-wasting trial assembly by adjusting the installation angles of stages is needed to meet the requirements due to the lack of effective analysis methods. Furthermore, there is no quick way to find out where the problem is and how to repair the parts when the installation-angle-adjusting method fails. This article focuses on a solution to optimize the installation angle of each stage and to make repair decisions in the assembly process. The run-out data are processed by least square method to get the spatial positions and attitudes of flanges and a deviation propagation analysis model is built by virtue of homogeneous coordinate transformation theory to predict the accumulative errors of each stage. The eccentricities of stages are evaluated with reference to the common axis and the installation angles of stages are optimized by minimizing the sum of eccentricities. Sensitivities of eccentricity, eccentric angle and parallelism of each stage are analyzed and repair decisions for parts are made to meet more strict requirements. An example of a three-stage subassembly is presented to demonstrate the solution.

Active control of amplitude and phase of high-power RF systems in EAST ICRF heating experiments

Zhu Guanghui,Liu Lunan,Mao Yuzhou,Zhang Xinjun,Guo Yaoyao,Ai Lin,Jiang Runhao,Qin Chengming,Zhang Wei,Yang Hua,Yuan Shuai,Wang Lei,Ju Songqing,Wang Yongsheng,Sun Xuan,Yang Zhida,Wang Jinxin,Cheng Yan 한국원자력학회 2023 Nuclear Engineering and Technology Vol.55 No.2

The EAST ICRF system operating space has been extended in power and phase control with a low-level RF system for the new double-strap antenna. Then the multi-step power and periodic phase scanning experiment were conducted in L-mode plasma, respectively. In the power scanning experiment, the stored energy, radiation power, plasma impedance and the antenna's temperature all have positive responses during the short ramp-ups of PL;ICRF. The core ion temperature increased from 1 keV to 1.5 keV and the core heating area expanded from jZj 5 cmto jZj 10 cm during the injection of ICRF waves. In the phasing scanning experiment, in addition to the same conclusions as the previous relatively phasing scanning experiment, the superposition effect of the fluctuation of stored energy, radiation power and neutron yield caused by phasing change with dual antenna, resulting in the amplitude and phase shift, was also observed. The active control of RF output facilitates the precise control of plasma profiles and greatly benefits future experimental exploration.

Finite Frequency Vibration Suppression for Space Flexible Structures in Tip Position Control

Shidong Xu,Guanghui Sun,Zhan Li 제어·로봇·시스템학회 2018 International Journal of Control, Automation, and Vol.16 No.3

This paper presents a novel control strategy for the tip position and vibration control of a class of space flexible structures. The proposed control algorithm consists of finite frequency H∞ vibration control technique and fractional-order PDv control technique. More specially, a new finite frequency H∞ controller working in the inner feedback loop is proposed to suppress vibration modes and external disturbances, and a new fractional-order PDv controller is developed in the outer feedback loop to guarantee the desired position tracking performance. Compared with conventional methods, the proposed one could achieve better control results. Finally, an illustrative example is presented to demonstrate the robustness and effectiveness of the proposed composite control strategy

Thermal-hydraulic analysis of a new conceptual heat pipe cooled small nuclear reactor system

Wang, Chenglong,Sun, Hao,Tang, Simiao,Tian, Wenxi,Qiu, Suizheng,Su, Guanghui Korean Nuclear Society 2020 Nuclear Engineering and Technology Vol.52 No.1

Small nuclear reactor features higher power capacity, longer operation life than conventional power sources. It could be an ideal alternative of existing power source applied for special equipment for terrestrial or underwater missions. In this paper, a 25kWe heat pipe cooled reactor power source applied for multiple use is preliminary designed. Based on the design, a thermal-hydraulic analysis code for heat pipe cooled reactor is developed to analyze steady and transient performance of the designed nuclear reactor. For reactor design, UN fuel with 65% enrichment and potassium heat pipes are adopted in the reactor core. Tungsten and LiH are adopted as radiation shield on both sides of the reactor core. The reactor is controlled by 6 control drums with B₄C neutron absorbers. Thermoelectric generator (TEG) converts fission heat into electricity. Cooling water removes waste heat out of the reactor. The thermal-hydraulic characteristics of heat pipes are simulated using thermal resistance network method. Thermal parameters of steady and transient conditions, such as the temperature distribution of every key components are obtained. Then the postulated reactor accidents for heat pipe cooled reactor, including power variation, single heat pipe failure and cooling channel blockage, are analyzed and evaluated. Results show that all the designed parameters satisfy the safety requirements. This work could provide reference to the design and application of the heat pipe cooled nuclear power source.

Active Speed Control of Belt Conveyor with Variable Speed Interval Based on Fuzzy Algorithm

Zhou Qixun,Gong Hao,Sun Wenhao,Yan Qi,Shi Keke,Du Guanghui 대한전기학회 2024 Journal of Electrical Engineering & Technology Vol.19 No.3

Aiming at the problems of too fast adjustment frequency, unstable material flling rate and fuctuation of material fow at the boundary of speed interval caused by unreasonable setting of speed interval in traditional active speed control strategy based on hierarchical speed regulation. An active speed control strategy based on fuzzy algorithm is proposed for belt conveyor. The material flling rate of the belt is taken as input, and the double-layer fuzzy boundary is set according to the expected value of the material flling rate to adjust the speed of the belt conveyor. The adjustment time of diferent speed intervals is given according to the estimation-calculation-optimization method. The simulation results of the double belt conveyor system show that compared with the active speed control strategy based on hierarchical speed regulation, the active speed control strategy can not only stabilize the material flling rate of the downstream belt conveyor near the expected value and improve the stability of transportation, but also reduce the energy by about 20.69% per hour on average. The subsequent experimental results also verify the efectiveness of the proposed active speed control strategy, which can achieve more sustainable operation of the belt conveyor.

Strain-Dependent Constitutive Analysis of Hot Deformation and Hot Workability of T4-Treated ZK60 Magnesium Alloy

Hui Yu,Huashun Yu,Guanghui Min,박성수,Bong Sun You,Young Min Kim 대한금속·재료학회 2013 METALS AND MATERIALS International Vol.19 No.4

The hot deformation behavior of T4-treated ZK60 magnesium alloy was investigated in a compression test conducted with a thermo-mechanical simulator at a temperature range of 523 K to 673 K and a strain rate of 0.001 s−1 to 1 s−1. The results show that the flow stress increases as the deformation temperature decreases and the strain rate increases. Strain-dependent constitutive relationships were developed using regression method and artificial neural network, and good agreements between the experimentally measured values and the predicted ones were achieved. The work hardening analysis and onset of dynamic recrystallization (DRX) were investigated. The processing map reveals a domain of DRX at the temperature range of 620-673 K and strain rate range of 0.001-0.01 s−1, with its peak efficiency of 32% at 623 K and 0.001 s−1,which are the optimum values of the parameters for hot working of the T4-treated ZK60 alloy. The strain level has a great effect on the processing maps and lower temperatures and higher strain rates should be avoided during hot working processes. DRX model indicates that DRX of ZK60 alloy is controlled by the rate of nucleation, which is slower than the rate of migration.

Design of the energy-balanced wireless sensor networks for 3D seismic exploration

Xiaohua Zhou,Jianbin Zheng,Xinkai Meng,Guanghui Sun,Ruyun Tian 한국통신학회 2023 ICT Express Vol.9 No.3

Wireless Sensor Networks for 3D Seismic Exploration are large-scale and long-term networks to ensure high resolution. Energy balance is essential to avoid interruption of the whole network. In this paper, the hybrid wireless network architecture is designed for low-power monitoring system. An energy-balanced clustering method is developed to prolong network lifetime. The partial energy factor is introduced to optimize scheduling of cluster head nodes. An improved ant colony algorithm for energy-efficient clustering and routing network (IACA-EECR) is proposed to find optimal path. The results show the proposed architecture outperforms the existing platform. Extensive tests validate energy efficiency and network performance.

Production of diacylglycerols by esterification of oleic acid with glycerol catalyzed by diatomite loaded SO4 2-/TiO2

Zhen Zhang,Hui Hua Huang,Xiang Ma,Guanghui Li,Yong Wang,Guo Sun,Yinglai Teng,Rian Yan,Ning Zhang,AiJun Li 한국공업화학회 2017 Journal of Industrial and Engineering Chemistry Vol.53 No.-

A new and efficient technique is described for the production of diacylglycerols (DAGs) by the esterification of oleic acid with glycerol catalyzed by diatomite-loaded SO4 2/TiO2. DAGs show some potential health benefits compared to triacylglycerols, and also can be used to produce the novel industrial plasticizer epoxy fatty acid methyl ester in material science. Diatomite-loaded SO4 2/TiO2 catalyst was prepared and characterized, and the selected conditions for the synthesis of DAGs were determined to be: reaction time = 6.0 h, temperature = 210 C, catalyst loading = 0.1% of the oleic acid weight, and mass ratio of oleic acid to glycerol = 2:1. Under these conditions, DAGs yield reached 59.6% with a purity of 69.6% after a one-stage molecular distillation. Diatomite-loaded SO4 2/TiO2 as a solid catalyst could be recycled and reused with high catalytic efficiency. Under the same conditions, diatomite-loaded SO4 2/TiO2 showed a better catalytic performance than the commercial solid acid SO4 2/ZrO2-Al2O3. Based on this, a two-step reaction method for the production of DAGs was performed and provided a yield similar to the one-step method (58.3% vs. 59.6%), but with a shorter reaction time (4 h vs. 6 h). It is concluded that a two-step reaction method could be a better alternative to the one-step production of DAGs in the presence of diatomite-loaded SO4 2/TiO2.

China Consensus Document on Allergy Diagnostics

Chen Hao,Li Jing,Cheng Lei,Gao Zhongshan,Lin Xiaoping,Zhu Rongfei,Yang Lin,Tao Ailin,Hong Haiyu,Tang Wei,Guo Yinshi,Huang Huaiqiu,Sun Jinlyu,Lai He,Lei Cheng,Liu Guanghui,Xiang Li,Chen Zhuanggui,Ma Ha 대한천식알레르기학회 2021 Allergy, Asthma & Immunology Research Vol.13 No.2

The prevalence of allergic diseases has increased dramatically in recent years in China, affecting the quality of life in 40% of the population. The identification of allergens is the key to the diagnosis of allergic diseases. Presently, several methods of allergy diagnostics are available in China, but they have not been standardized. Additionally, cross-sensitization and co-sensitization make allergy diagnostics even more complicated. Based on 4 aspects of allergic disease (mechanism, diagnosis procedures, allergen detection in vivo and in vitro as well as the distribution map of the most important airborne allergens in China) and by referring to the consensus of the European Society of Allergy and Clinical Immunology, the World Allergy Organization, and the important literature on allergy diagnostics in China in recent years, we drafted this consensus of allergy diagnostics with Chinese characteristics. It aims to standardize the diagnostic methods of allergens and provides a reference for health care givers. The current document was prepared by a panel of experts from the main stream of professional allergy associations in China.