Pub Date : 2024-08-28DOI: 10.1016/j.net.2024.08.054
Amruta Pasarkar, S. Balaguru
In sodium-cooled fast reactors (SFR), 316L(N) SS grid plate is hardfaced with Ni-Cr-B-Si alloy to achieve higher wear resistance. Tensile and fatigue forces are acting at the interface between substrate and deposit due to different thermal expansion coefficients of those two materials, which can cause cracking of deposit and fracture during operation. Thus, it is very important to consider appropriate hardfacing method which can provide higher tensile and fatigue strength to avoid cracking/debonding at the interface. To find a solution to this problem, two hardfacing techniques, namely Gas Tungsten Arc (GTA) and Laser cladding (LC), are taken into consideration. Hardfaced specimens are prepared using each process on which tensile and high cycle fatigue tests are conducted. From the experimental testing, stress-strain and S-N curves are generated to predict the tensile and fatigue behaviour of specimens. Fractographic studies are conducted at fractured surfaces to understand the fatigue crack nucleation and propagation characteristics. The experimental results for both processes are compared. Tensile and fatigue strength of LC specimens are ∼11 % and ∼17 % less than those of GTA specimens due to its higher brittleness. Thus, GTA process is recommended as the efficient hardfacing process for grid plate of SFR.
{"title":"Comparative study on tensile and high cycle fatigue behaviour of 316L(N) SS hardfaced with Ni-Cr-B-Si alloy by GTA and laser cladding processes","authors":"Amruta Pasarkar, S. Balaguru","doi":"10.1016/j.net.2024.08.054","DOIUrl":"https://doi.org/10.1016/j.net.2024.08.054","url":null,"abstract":"In sodium-cooled fast reactors (SFR), 316L(N) SS grid plate is hardfaced with Ni-Cr-B-Si alloy to achieve higher wear resistance. Tensile and fatigue forces are acting at the interface between substrate and deposit due to different thermal expansion coefficients of those two materials, which can cause cracking of deposit and fracture during operation. Thus, it is very important to consider appropriate hardfacing method which can provide higher tensile and fatigue strength to avoid cracking/debonding at the interface. To find a solution to this problem, two hardfacing techniques, namely Gas Tungsten Arc (GTA) and Laser cladding (LC), are taken into consideration. Hardfaced specimens are prepared using each process on which tensile and high cycle fatigue tests are conducted. From the experimental testing, stress-strain and S-N curves are generated to predict the tensile and fatigue behaviour of specimens. Fractographic studies are conducted at fractured surfaces to understand the fatigue crack nucleation and propagation characteristics. The experimental results for both processes are compared. Tensile and fatigue strength of LC specimens are ∼11 % and ∼17 % less than those of GTA specimens due to its higher brittleness. Thus, GTA process is recommended as the efficient hardfacing process for grid plate of SFR.","PeriodicalId":19272,"journal":{"name":"Nuclear Engineering and Technology","volume":"24 1","pages":""},"PeriodicalIF":2.7,"publicationDate":"2024-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142207225","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-28DOI: 10.1016/j.net.2024.08.052
Almog Biton, Evgeny Rabinovich, Erez Gilad
This work presents an experimental study of five threshold velocities for air-water flow in three different vertical channels. The measured threshold velocities included onset flooding (OF), end flooding (EF), onset deflooding (OD), end deflooding (ED), and minimum pressure (MP) velocities. The experimental system includes a transparent vertical tube of 52.5 mm inner diameter and 1500 mm length. The test channel can be easily changed from a tube to an annular shape by inserting a cylindrical test element. A counter-current or concurrent upward flow was achieved by blowing air upward from the channel's bottom and flowing water from its top. The threshold velocities were determined by analyzing the pressure drop versus air superficial velocity. Findings revealed evident hysteresis between the end flooding and onset deflooding velocities. In contrast, the end deflooding and onset flooding velocities were found to be identical. The end flooding velocity was indifferent to the water's superficial velocity for all three channel geometries. A generalized gas-liquid flow state diagram for vertical channels is developed based on the present empirical analysis for different threshold velocities.
{"title":"Experimental investigation of threshold velocities for air-water two-phase flow in a vertical tube and annular channels","authors":"Almog Biton, Evgeny Rabinovich, Erez Gilad","doi":"10.1016/j.net.2024.08.052","DOIUrl":"https://doi.org/10.1016/j.net.2024.08.052","url":null,"abstract":"This work presents an experimental study of five threshold velocities for air-water flow in three different vertical channels. The measured threshold velocities included onset flooding (OF), end flooding (EF), onset deflooding (OD), end deflooding (ED), and minimum pressure (MP) velocities. The experimental system includes a transparent vertical tube of 52.5 mm inner diameter and 1500 mm length. The test channel can be easily changed from a tube to an annular shape by inserting a cylindrical test element. A counter-current or concurrent upward flow was achieved by blowing air upward from the channel's bottom and flowing water from its top. The threshold velocities were determined by analyzing the pressure drop versus air superficial velocity. Findings revealed evident hysteresis between the end flooding and onset deflooding velocities. In contrast, the end deflooding and onset flooding velocities were found to be identical. The end flooding velocity was indifferent to the water's superficial velocity for all three channel geometries. A generalized gas-liquid flow state diagram for vertical channels is developed based on the present empirical analysis for different threshold velocities.","PeriodicalId":19272,"journal":{"name":"Nuclear Engineering and Technology","volume":"54 1","pages":""},"PeriodicalIF":2.7,"publicationDate":"2024-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142207224","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-27DOI: 10.1016/j.net.2024.08.049
Shuiqiang Duan, Minggang Li, Jiaming Li, Tongxi Li, Changhua Nie, Zumao Yang, Jun Hu
The accurate measurement of the water level on the secondary side of the steam generator (SG) plays a crucial role in the safe and stable operation of the primary and secondary circuits of the nuclear power plant. In order to study the feasibility of applying the magnetostrictive liquid level gauge to the water level measurement of SG, the measurement results of the magnetostrictive liquid level gauge under the steady and transient conditions were obtained and compared with the traditional differential pressure liquid level gauge. The results indicated that the magnetostrictive liquid level gauge had good measurement accuracy under the cold-steady condition, thermal-steady condition and transient pressurization condition. The design parameters of float and operating parameters were necessary to correct the measurement results of magnetostrictive water level gauge. The measurement results under the transient depressurization condition were affected by the fluid movement in the container, resulting in a decrease in measurement accuracy. The results indicated that the magnetostrictive liquid level gauge had the potential to be used for water level measurement of SG in nuclear power plant.
{"title":"Research on magnetostrictive liquid level gauge for water level measurement of steam generator","authors":"Shuiqiang Duan, Minggang Li, Jiaming Li, Tongxi Li, Changhua Nie, Zumao Yang, Jun Hu","doi":"10.1016/j.net.2024.08.049","DOIUrl":"10.1016/j.net.2024.08.049","url":null,"abstract":"<div><div>The accurate measurement of the water level on the secondary side of the steam generator (SG) plays a crucial role in the safe and stable operation of the primary and secondary circuits of the nuclear power plant. In order to study the feasibility of applying the magnetostrictive liquid level gauge to the water level measurement of SG, the measurement results of the magnetostrictive liquid level gauge under the steady and transient conditions were obtained and compared with the traditional differential pressure liquid level gauge. The results indicated that the magnetostrictive liquid level gauge had good measurement accuracy under the cold-steady condition, thermal-steady condition and transient pressurization condition. The design parameters of float and operating parameters were necessary to correct the measurement results of magnetostrictive water level gauge. The measurement results under the transient depressurization condition were affected by the fluid movement in the container, resulting in a decrease in measurement accuracy. The results indicated that the magnetostrictive liquid level gauge had the potential to be used for water level measurement of SG in nuclear power plant.</div></div>","PeriodicalId":19272,"journal":{"name":"Nuclear Engineering and Technology","volume":"56 12","pages":"Pages 5422-5427"},"PeriodicalIF":2.6,"publicationDate":"2024-08-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142207227","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-26DOI: 10.1016/j.net.2024.08.046
Jong-Bae Hwang, Injin Sa, Eung-Seon Kim, Dong-Hyun Lee
High temperature mechanical properties of diffusion welded Alloy 800H was investigated to fabricate a printed circuit heat exchanger (PCHE) for high temperature reactor (HTR) systems. Surface treatment was performed on Alloy 800H to transform the solubility product () to exceed the reaction quotient (). The surface treatment facilitated the grain boundary migration across the interface. The yield strengths exceeded the values described in ASME Section III Division 5 Table HBB-I-14.5 up to 760 °C, while the tensile strengths were comparable to Table HBB-3225-1 up to 700 °C. At 760 °C, the tensile strength was ∼30 MPa lower than the code. The stress-to-rupture values exceeded the expected minimum stress-to-rupture values of Alloy 800H described in Table HBB-I-14.6C. The ductility of the diffusion weldment acquired from the tensile test was comparable to the as-received Alloy 800H. Meanwhile, the formation of the secondary precipitates on the interface during the stress-to-rupture test deteriorated the ductility of the diffusion weldment, which induced intergranular fracture.
{"title":"High temperature mechanical properties of diffusion welded alloy 800H","authors":"Jong-Bae Hwang, Injin Sa, Eung-Seon Kim, Dong-Hyun Lee","doi":"10.1016/j.net.2024.08.046","DOIUrl":"https://doi.org/10.1016/j.net.2024.08.046","url":null,"abstract":"High temperature mechanical properties of diffusion welded Alloy 800H was investigated to fabricate a printed circuit heat exchanger (PCHE) for high temperature reactor (HTR) systems. Surface treatment was performed on Alloy 800H to transform the solubility product () to exceed the reaction quotient (). The surface treatment facilitated the grain boundary migration across the interface. The yield strengths exceeded the values described in ASME Section III Division 5 Table HBB-I-14.5 up to 760 °C, while the tensile strengths were comparable to Table HBB-3225-1 up to 700 °C. At 760 °C, the tensile strength was ∼30 MPa lower than the code. The stress-to-rupture values exceeded the expected minimum stress-to-rupture values of Alloy 800H described in Table HBB-I-14.6C. The ductility of the diffusion weldment acquired from the tensile test was comparable to the as-received Alloy 800H. Meanwhile, the formation of the secondary precipitates on the interface during the stress-to-rupture test deteriorated the ductility of the diffusion weldment, which induced intergranular fracture.","PeriodicalId":19272,"journal":{"name":"Nuclear Engineering and Technology","volume":"13 1","pages":""},"PeriodicalIF":2.7,"publicationDate":"2024-08-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142207230","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-26DOI: 10.1016/j.net.2024.08.050
Jin-Mok Hur, Jungho Hur, Yung-Zun Cho, Chang Hwa Lee
The separation of high heat load fission products, such as alkaline earth metals, from nuclear spent fuel can significantly reduce the burden of spent fuel disposal. This study investigates the feasibility of separating strontium and barium from light water reactor spent fuel through non-aqueous processes. Process flows were developed for treating spent nuclear fuel by heating it at high temperatures to remove volatile nuclides, followed by chlorination with a chlorinating agent. The chlorinated products were then treated with a precipitating agent in LiCl-KCl molten salt for further separation. The remaining liquid was distilled to recover strontium and barium. Thermodynamic equilibrium calculations were conducted for the process flows. Under the conditions of the process flows, the chlorinating agents MgCl and NHCl both converted SrO and BaO entirely into SrCl and BaCl, respectively. The precipitating agent LiCO exhibited superior separation effectiveness compared to LiPO. Thermodynamic calculations indicate that strontium and barium recovered by MgCl chlorination, LiCO precipitation, and distillation will contain 0.18 %, 1.06 %, and 0.32 % impurities in terms of mass, radioactivity, and decay heat, respectively.
{"title":"Thermodynamic study on the separation of strontium and barium from LWR spent fuel","authors":"Jin-Mok Hur, Jungho Hur, Yung-Zun Cho, Chang Hwa Lee","doi":"10.1016/j.net.2024.08.050","DOIUrl":"https://doi.org/10.1016/j.net.2024.08.050","url":null,"abstract":"The separation of high heat load fission products, such as alkaline earth metals, from nuclear spent fuel can significantly reduce the burden of spent fuel disposal. This study investigates the feasibility of separating strontium and barium from light water reactor spent fuel through non-aqueous processes. Process flows were developed for treating spent nuclear fuel by heating it at high temperatures to remove volatile nuclides, followed by chlorination with a chlorinating agent. The chlorinated products were then treated with a precipitating agent in LiCl-KCl molten salt for further separation. The remaining liquid was distilled to recover strontium and barium. Thermodynamic equilibrium calculations were conducted for the process flows. Under the conditions of the process flows, the chlorinating agents MgCl and NHCl both converted SrO and BaO entirely into SrCl and BaCl, respectively. The precipitating agent LiCO exhibited superior separation effectiveness compared to LiPO. Thermodynamic calculations indicate that strontium and barium recovered by MgCl chlorination, LiCO precipitation, and distillation will contain 0.18 %, 1.06 %, and 0.32 % impurities in terms of mass, radioactivity, and decay heat, respectively.","PeriodicalId":19272,"journal":{"name":"Nuclear Engineering and Technology","volume":"4 1","pages":""},"PeriodicalIF":2.7,"publicationDate":"2024-08-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142207229","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This paper presents an innovative design of a steel-reinforced concrete (SRC) column-reinforced concrete (RC) slab joint based on a concept of the strong column and weak slab. In this study, two 1:2 reduced scale SRC column-RC slab joint specimens are designed and fabricated for horizontal cyclic loading tests based on side slab-column joints of an auxiliary plant of a nuclear power plant. In order to ensure the ease of construction and stability of the connection between the reinforcement and the section steel, one structure (SR-2) with steel sleeves welded to the section steel and connected to the reinforcement in the joint area and the other structure (SR-1) with a stiffened steel plate (SSP) in the connection area on the basis of SR-2 were fabricated and tested in order to investigate the structural strengthening the joint. Based on the test results, the damage modes, hysteresis performance, energy dissipation capacity and stiffness degradation of the specimens were studied. A finite element analysis (FEA) model was developed and verified with the experimental results. The verified FEA model was used for parametrical study on effects of thickness, outer dimensions of SSP, a longitudinal reinforcement ratio in the RC slab and an axial pressure ratio. The test results show that the damage mode of specimens is shear failure at the RC slab and the damage of the SRC column is minor, which is in line with the design concept of the strong column and weak slab. The parametric study shows that increasing the thickness and outer size of SSP can improve the load-bearing capacity and initial stiffness of joints.
{"title":"Experimental and numerical study on seismic behaviors of SRC column-RC slab joints in NPP","authors":"Dayang Wang, Qiang Liu, Yuanqi Song, Yong Zhu, Yongshan Zhang","doi":"10.1016/j.net.2024.08.045","DOIUrl":"https://doi.org/10.1016/j.net.2024.08.045","url":null,"abstract":"This paper presents an innovative design of a steel-reinforced concrete (SRC) column-reinforced concrete (RC) slab joint based on a concept of the strong column and weak slab. In this study, two 1:2 reduced scale SRC column-RC slab joint specimens are designed and fabricated for horizontal cyclic loading tests based on side slab-column joints of an auxiliary plant of a nuclear power plant. In order to ensure the ease of construction and stability of the connection between the reinforcement and the section steel, one structure (SR-2) with steel sleeves welded to the section steel and connected to the reinforcement in the joint area and the other structure (SR-1) with a stiffened steel plate (SSP) in the connection area on the basis of SR-2 were fabricated and tested in order to investigate the structural strengthening the joint. Based on the test results, the damage modes, hysteresis performance, energy dissipation capacity and stiffness degradation of the specimens were studied. A finite element analysis (FEA) model was developed and verified with the experimental results. The verified FEA model was used for parametrical study on effects of thickness, outer dimensions of SSP, a longitudinal reinforcement ratio in the RC slab and an axial pressure ratio. The test results show that the damage mode of specimens is shear failure at the RC slab and the damage of the SRC column is minor, which is in line with the design concept of the strong column and weak slab. The parametric study shows that increasing the thickness and outer size of SSP can improve the load-bearing capacity and initial stiffness of joints.","PeriodicalId":19272,"journal":{"name":"Nuclear Engineering and Technology","volume":"77 1","pages":""},"PeriodicalIF":2.7,"publicationDate":"2024-08-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142207231","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-26DOI: 10.1016/j.net.2024.08.039
Ke Wu, Jun Zhang, Yong Cheng, Qingxi Yang, Hongtao Pan, Tao Wang, Aiming Liu, Hao Han
This paper proposed a framework of a dual-arm-based robotic maintenance system, including visual recognition, trajectory planning, force feedback control and master–slave control. To meet the requirements of automated maintenance, we proposed an improved design for the structures of the first wall tiles and support boards, and established a complete communication structure for the maintenance system that can adapt to different hardware versions. Based on the proposed framework, an experimental platform with dual-arm manipulator was established to demonstrate the maintenance scenario of the FW of the blanket in Vacuum Vessel (VV). The experimental result verified the feasibility of automated robotic maintenance system applied to the future fusion reactor.
{"title":"The design and implementation of automated maintenance system for the first-wall based on dual-arm manipulator","authors":"Ke Wu, Jun Zhang, Yong Cheng, Qingxi Yang, Hongtao Pan, Tao Wang, Aiming Liu, Hao Han","doi":"10.1016/j.net.2024.08.039","DOIUrl":"https://doi.org/10.1016/j.net.2024.08.039","url":null,"abstract":"This paper proposed a framework of a dual-arm-based robotic maintenance system, including visual recognition, trajectory planning, force feedback control and master–slave control. To meet the requirements of automated maintenance, we proposed an improved design for the structures of the first wall tiles and support boards, and established a complete communication structure for the maintenance system that can adapt to different hardware versions. Based on the proposed framework, an experimental platform with dual-arm manipulator was established to demonstrate the maintenance scenario of the FW of the blanket in Vacuum Vessel (VV). The experimental result verified the feasibility of automated robotic maintenance system applied to the future fusion reactor.","PeriodicalId":19272,"journal":{"name":"Nuclear Engineering and Technology","volume":"99 1","pages":""},"PeriodicalIF":2.7,"publicationDate":"2024-08-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142207228","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-24DOI: 10.1016/j.net.2024.08.047
Qianxu Wang, Yuanlai Xie, Huihui Hong, Yang Zhu, Fang Wang, Kun Tian, Bin Li
As an important component of Negative ion based Neutral Beam Injector (NNBI), the cryopump mainly provides a suitable vacuum environment for beam generation and transmission. In the paper, Liquid nitrogen (LN2) pipe structure models of two cryopumps were established for simulation and experimental studies. Thermal analysis of the thermal radiation shielding baffle (LN2 cooling) was carried out by Ansys steady-state thermal analysis software, while Fluent was used to simulate the two-phase flow in the LN2 pipeline, then the pressure drops, temperature, velocity, gas-phase volume fraction, and other parameters of the two pipeline structures were analyzed and compared. The simulation results show that the optimized structure B can reduce the pressure drop by 3 bar, the outlet temperature of structure A is 78.8 K, the outlet temperature of structure B is 79.2 K, the temperature difference is 0.4 K. The outlet velocity increases from 2.067 m/s to 4.947 m/s for Structure A, and from 1.096 m/s to 6.614 m/s for Structure B. The experiment results show that the outlet temperature of structure A is 79.4 K, meanwhile the outlet temperature of structure B is 80.1 K, the optimized structure B can reduce the pressure drop about 3 bar.
作为负离子中性束注入器（NNBI）的重要组成部分，低温泵主要为束流的产生和传输提供合适的真空环境。本文建立了两个低温泵的液氮（LN2）管道结构模型，并进行了模拟和实验研究。利用 Ansys 稳态热分析软件对热辐射屏蔽挡板（LN2 冷却）进行了热分析，同时利用 Fluent 对 LN2 管道中的两相流动进行了模拟，然后对两种管道结构的压降、温度、速度、气相体积分数等参数进行了分析和比较。模拟结果表明，优化后的结构 B 可使压降降低 3 bar，结构 A 的出口温度为 78.8 K，结构 B 的出口温度为 79.2 K，温差为 0.4 K，出口速度从结构 A 的 2.067 m/s 增加到 4.实验结果表明，结构 A 的出口温度为 79.4 K，而结构 B 的出口温度为 80.1 K，优化后的结构 B 可减少压降约 3 bar。
{"title":"Analysis and optimization of LN2 two-phase flow in CRAFT NNBI cryopump","authors":"Qianxu Wang, Yuanlai Xie, Huihui Hong, Yang Zhu, Fang Wang, Kun Tian, Bin Li","doi":"10.1016/j.net.2024.08.047","DOIUrl":"https://doi.org/10.1016/j.net.2024.08.047","url":null,"abstract":"As an important component of Negative ion based Neutral Beam Injector (NNBI), the cryopump mainly provides a suitable vacuum environment for beam generation and transmission. In the paper, Liquid nitrogen (LN2) pipe structure models of two cryopumps were established for simulation and experimental studies. Thermal analysis of the thermal radiation shielding baffle (LN2 cooling) was carried out by Ansys steady-state thermal analysis software, while Fluent was used to simulate the two-phase flow in the LN2 pipeline, then the pressure drops, temperature, velocity, gas-phase volume fraction, and other parameters of the two pipeline structures were analyzed and compared. The simulation results show that the optimized structure B can reduce the pressure drop by 3 bar, the outlet temperature of structure A is 78.8 K, the outlet temperature of structure B is 79.2 K, the temperature difference is 0.4 K. The outlet velocity increases from 2.067 m/s to 4.947 m/s for Structure A, and from 1.096 m/s to 6.614 m/s for Structure B. The experiment results show that the outlet temperature of structure A is 79.4 K, meanwhile the outlet temperature of structure B is 80.1 K, the optimized structure B can reduce the pressure drop about 3 bar.","PeriodicalId":19272,"journal":{"name":"Nuclear Engineering and Technology","volume":"10 1","pages":""},"PeriodicalIF":2.7,"publicationDate":"2024-08-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142207241","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Neutral beam injection is one of the effective heating methods in the field of magnetic confinement fusion, and neutralization is the most crucial link in the case of negative ions. To further increase the neutral beam injection power, improve the long pulse operation capability, and optimize the efficiency of the NNBI system, further research and verification about the neutralization mode are needed. Theoretically, photoneutralization can achieve more than 90 % neutralization efficiency. However, maintaining stable operation of the megawatt laser cavity over extended periods poses corresponding challenges. Additionally, the cost associated with laser target surpasses the benefit gained from increased neutralization efficiency, leading to its lack of practical application thus far. This paper proposes a solution to these issues by designing a single-channel, multi-fold photoneutralization verification system utilizing the CRAFT NNBI one-quarter and one-half size negative source test equipment. An outline of the system's test and diagnostics approach is provided. Key parameters such as laser target thickness, negative ion energy, beam shape and efficiency of the photoneutralization system are numerically calculated. Combined with the experimental data of the negative source test platform, theoretical calculations show that the neutralization efficiency can achieve 63 % with the system efficiency exceeding 40 %. Even by increasing the incident laser power or the number of reflections, neutralization efficiency can be increased to 95 %, with a simultaneous increase in system efficiency to 60 %. Maintaining efficiency while increasing incident laser power could reduce the number of reflections to approximately ten, reaching an acceptable threshold. However, this adjustment will increase the irradiation density of a single mirror from 660W/mm increases to 3000W/mm. This paper methodically designs a practical laser neutralization verification platform, which is expected to substantially improve the neutralization efficiency, and facilitate practical application and validation.
{"title":"Conceptional design of photoneutralization test system for negative ion-based neutral beam injection","authors":"Hui-hui Hong, Li-zhen Liang, Yuan-lai Xie, Qian-xu Wang, Zhuo Pan, Yao Jiang","doi":"10.1016/j.net.2024.08.024","DOIUrl":"https://doi.org/10.1016/j.net.2024.08.024","url":null,"abstract":"Neutral beam injection is one of the effective heating methods in the field of magnetic confinement fusion, and neutralization is the most crucial link in the case of negative ions. To further increase the neutral beam injection power, improve the long pulse operation capability, and optimize the efficiency of the NNBI system, further research and verification about the neutralization mode are needed. Theoretically, photoneutralization can achieve more than 90 % neutralization efficiency. However, maintaining stable operation of the megawatt laser cavity over extended periods poses corresponding challenges. Additionally, the cost associated with laser target surpasses the benefit gained from increased neutralization efficiency, leading to its lack of practical application thus far. This paper proposes a solution to these issues by designing a single-channel, multi-fold photoneutralization verification system utilizing the CRAFT NNBI one-quarter and one-half size negative source test equipment. An outline of the system's test and diagnostics approach is provided. Key parameters such as laser target thickness, negative ion energy, beam shape and efficiency of the photoneutralization system are numerically calculated. Combined with the experimental data of the negative source test platform, theoretical calculations show that the neutralization efficiency can achieve 63 % with the system efficiency exceeding 40 %. Even by increasing the incident laser power or the number of reflections, neutralization efficiency can be increased to 95 %, with a simultaneous increase in system efficiency to 60 %. Maintaining efficiency while increasing incident laser power could reduce the number of reflections to approximately ten, reaching an acceptable threshold. However, this adjustment will increase the irradiation density of a single mirror from 660W/mm increases to 3000W/mm. This paper methodically designs a practical laser neutralization verification platform, which is expected to substantially improve the neutralization efficiency, and facilitate practical application and validation.","PeriodicalId":19272,"journal":{"name":"Nuclear Engineering and Technology","volume":"18 1","pages":""},"PeriodicalIF":2.7,"publicationDate":"2024-08-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142207242","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-21DOI: 10.1016/j.net.2024.08.027
Sherif A. Taalab , Mohamed Y. Hanfi , Mohamed S. Ahmed , Diaa A. Saadawi , Ahmed K. Sakr , Mayeen Uddin Khandaker , Mahmoud R. Khattab
The present study employed statistical methods to evaluate the possible radiological hazards linked to granitic rocks-bearing mineralization in the ELgarra region of Egypt. The geological structures influence the occurrence of uranium mineralization in this area and are primarily associated with altered granites. Gamma-ray spectrometry was utilized to examine the quantities of 238U, 232Th, and 40K in granitic rock samples. The recorded levels of radioisotope activity concentrations in the analyzed regions ranged from 374 to 1740 Bq.kg−1238U, with an average of 1018 Bq.kg−1. For 232Th, the range was between 71 and 163 Bq.kg−1, with an average of 119 Bq.kg−1. Lastly, for 40K, the range was 756–1789 Bq.kg−1, with an average of 1212 Bq.kg−1. The detected levels of 238U, 232Th, and 40K in the examined rock samples were observed to exceed the permissible limits of 35, 45, and 412 Bq.kg−1, respectively. The primary radiological risks linked to these granitic rocks were attributed to the gamma rays released by the radioactive elements. Estimations of the radiological hazards in the granitic rocks were made, and statistical approaches were utilized to demonstrate the associations among radionuclides and radiological factors. The assessment confirmed that uranium, potassium, and their respective minerals in the granitic rocks were the key factors contributing to the radiological risks. As a result, the study determined that the granite rocks found in the study area needed precautions to be taken due to their high levels of radioactivity.
{"title":"Geochemical evaluation and hazard indices due to radioactive minerals associated with granitic areas","authors":"Sherif A. Taalab , Mohamed Y. Hanfi , Mohamed S. Ahmed , Diaa A. Saadawi , Ahmed K. Sakr , Mayeen Uddin Khandaker , Mahmoud R. Khattab","doi":"10.1016/j.net.2024.08.027","DOIUrl":"10.1016/j.net.2024.08.027","url":null,"abstract":"<div><div>The present study employed statistical methods to evaluate the possible radiological hazards linked to granitic rocks-bearing mineralization in the ELgarra region of Egypt. The geological structures influence the occurrence of uranium mineralization in this area and are primarily associated with altered granites. Gamma-ray spectrometry was utilized to examine the quantities of <sup>238</sup>U, <sup>232</sup>Th, and <sup>40</sup>K in granitic rock samples. The recorded levels of radioisotope activity concentrations in the analyzed regions ranged from 374 to 1740 Bq.kg<sup>−1</sup> <sup>238</sup>U, with an average of 1018 Bq.kg<sup>−1</sup>. For <sup>232</sup>Th, the range was between 71 and 163 Bq.kg<sup>−1</sup>, with an average of 119 Bq.kg<sup>−1</sup>. Lastly, for <sup>40</sup>K, the range was 756–1789 Bq.kg<sup>−1</sup>, with an average of 1212 Bq.kg<sup>−1</sup>. The detected levels of <sup>238</sup>U, <sup>232</sup>Th, and <sup>40</sup>K in the examined rock samples were observed to exceed the permissible limits of 35, 45, and 412 Bq.kg<sup>−1</sup>, respectively. The primary radiological risks linked to these granitic rocks were attributed to the gamma rays released by the radioactive elements. Estimations of the radiological hazards in the granitic rocks were made, and statistical approaches were utilized to demonstrate the associations among radionuclides and radiological factors. The assessment confirmed that uranium, potassium, and their respective minerals in the granitic rocks were the key factors contributing to the radiological risks. As a result, the study determined that the granite rocks found in the study area needed precautions to be taken due to their high levels of radioactivity.</div></div>","PeriodicalId":19272,"journal":{"name":"Nuclear Engineering and Technology","volume":"56 11","pages":"Pages 4921-4928"},"PeriodicalIF":2.6,"publicationDate":"2024-08-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142434255","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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