Tien Doan, Thi Thu My Trinh, Hong Khiem Le, Marina V. Frontasyeva, An Son Nguyen, Manh Hung Trinh, Van Dung Do, Tan Thong Vo, Xuan Vinh Ha
The aim of this investigation was to apply the moss biomonitoring technique using Barbula Indica moss and factor analysis to evaluate the possible sources of atmospheric pollution in the Thua Thien Hue province. The Barbula Indica moss samples were collected at sixteen sites in the areas of Thua Thien Hue province, the central Vietnam. The concentrations of thirty elements in the collected Barbula Indica moss samples were determined by neutron activation analyses at the reactor IBR-2 at the Joint Institute for Nuclear Research (JINR) in Dubna, Russian Federation. Factor analysis has been applied to the obtained concentrations to reveal the possible pollution sources. Rotated factor loadings suggested three factors, that could explained more than 84% of variability. Additionally, factor scores were calculated, that confirmed the presence of pollution sources in the corresponding sites.
{"title":"Using Factor Analysis To Find Source Atmospheric Pollution By Moss Technique","authors":"Tien Doan, Thi Thu My Trinh, Hong Khiem Le, Marina V. Frontasyeva, An Son Nguyen, Manh Hung Trinh, Van Dung Do, Tan Thong Vo, Xuan Vinh Ha","doi":"10.53747/nst.v12i4.352","DOIUrl":"https://doi.org/10.53747/nst.v12i4.352","url":null,"abstract":"The aim of this investigation was to apply the moss biomonitoring technique using Barbula Indica moss and factor analysis to evaluate the possible sources of atmospheric pollution in the Thua Thien Hue province. The Barbula Indica moss samples were collected at sixteen sites in the areas of Thua Thien Hue province, the central Vietnam. The concentrations of thirty elements in the collected Barbula Indica moss samples were determined by neutron activation analyses at the reactor IBR-2 at the Joint Institute for Nuclear Research (JINR) in Dubna, Russian Federation. Factor analysis has been applied to the obtained concentrations to reveal the possible pollution sources. Rotated factor loadings suggested three factors, that could explained more than 84% of variability. Additionally, factor scores were calculated, that confirmed the presence of pollution sources in the corresponding sites.","PeriodicalId":19445,"journal":{"name":"Nuclear Science and Technology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140445655","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Hieu Tran Trong, Huong Huynh Thi Thu, Son Le Van, Quang Nguyen Huu
The Compartment Model allows modeling the system flow to zones visually, in which each zone is characterized by a combination of basic mixing compartments. The localization of the flow zones, as well as the calculation of the volume zones and exchange rate between zones, was done based on the velocity field determined from the numerical simulation model. This study presents the results of applying the CM method to analyze the 2D basic non-reactive tank with dimensions of 100 cm x 100 cm x 10 cm and an inlet flow of about 3 - 6 L/min. The results show that the obtained CM model has 3 main flow zones including the convection zone, circulation zone and slow flow zone. The results of comparing the tracer response curves from the CM model and experiment with the root-mean-square error below 0,11 allow confirming the established CM model.
分区模型可以直观地模拟系统的分区流动，其中每个分区都由基本混合分区组合而成。流动区域的定位以及体积区域和区域间交换率的计算都是根据数值模拟模型确定的速度场进行的。本研究介绍了应用 CM 方法分析二维基本非反应槽的结果，该槽的尺寸为 100 厘米 x 100 厘米 x 10 厘米，入口流量约为 3 - 6 升/分钟。结果表明，得到的 CM 模型有 3 个主要流动区，包括对流区、循环区和缓流区。 通过比较 CM 模型和实验的示踪响应曲线，均方根误差低于 0.11，从而证实了所建立的 CM 模型。
{"title":"Study of the compartmental modelling method on the basic non-reactive tank","authors":"Hieu Tran Trong, Huong Huynh Thi Thu, Son Le Van, Quang Nguyen Huu","doi":"10.53747/nst.v12i2.342","DOIUrl":"https://doi.org/10.53747/nst.v12i2.342","url":null,"abstract":"The Compartment Model allows modeling the system flow to zones visually, in which each zone is characterized by a combination of basic mixing compartments. The localization of the flow zones, as well as the calculation of the volume zones and exchange rate between zones, was done based on the velocity field determined from the numerical simulation model. This study presents the results of applying the CM method to analyze the 2D basic non-reactive tank with dimensions of 100 cm x 100 cm x 10 cm and an inlet flow of about 3 - 6 L/min. The results show that the obtained CM model has 3 main flow zones including the convection zone, circulation zone and slow flow zone. The results of comparing the tracer response curves from the CM model and experiment with the root-mean-square error below 0,11 allow confirming the established CM model.","PeriodicalId":19445,"journal":{"name":"Nuclear Science and Technology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-11-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139239576","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Thi Hoang Xuan, Men Nguyen Thi, Tuyen Hoang Thi, Tuyen Ngo Van, Nhuan Hoang
The alkaline (NaOH) hydrometallurgy for monazite concentrate is currently being used in the industrial production of total rare earth oxides (TREOs) and thorium oxide (ThO2). Besides the acknowledged advantages, the hydrometallurgical process also has certain disadvantages such as the requirement for ultra-fine grinding to -325 mesh, and the hydrometallurgy time extended from 8 to 10 hours to achieve ~93 % efficiency. The present paper report a new roasting process using potassium hydroxide (KOH) applied to Vietnamese monazite concentrates. The experimental data were collected using mass analysis, XRD, and ICP-OES analysis. The optimal efficiency of the process is ~95% after roasting time of 0,5 hours, the temperature at 250oC, and KOH:monazite mass ratio = 1:1. Thereby, the alkaline (KOH) roasting process has solved the limitations of the alkaline (NaOH) hydrometallurgy and shows the development potential in deep processing of the monazite concentrate in Vietnam.
{"title":"Investigation of Vietnamese monazite concentrate decomposition by alkaline (KOH) baking method","authors":"Thi Hoang Xuan, Men Nguyen Thi, Tuyen Hoang Thi, Tuyen Ngo Van, Nhuan Hoang","doi":"10.53747/nst.v12i2.351","DOIUrl":"https://doi.org/10.53747/nst.v12i2.351","url":null,"abstract":"The alkaline (NaOH) hydrometallurgy for monazite concentrate is currently being used in the industrial production of total rare earth oxides (TREOs) and thorium oxide (ThO2). Besides the acknowledged advantages, the hydrometallurgical process also has certain disadvantages such as the requirement for ultra-fine grinding to -325 mesh, and the hydrometallurgy time extended from 8 to 10 hours to achieve ~93 % efficiency. The present paper report a new roasting process using potassium hydroxide (KOH) applied to Vietnamese monazite concentrates. The experimental data were collected using mass analysis, XRD, and ICP-OES analysis. The optimal efficiency of the process is ~95% after roasting time of 0,5 hours, the temperature at 250oC, and KOH:monazite mass ratio = 1:1. Thereby, the alkaline (KOH) roasting process has solved the limitations of the alkaline (NaOH) hydrometallurgy and shows the development potential in deep processing of the monazite concentrate in Vietnam.","PeriodicalId":19445,"journal":{"name":"Nuclear Science and Technology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-11-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139239108","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this paper we attempt to find the intermolecular force of charged AdS black holes (BH). We first write the equation of state of BH in the form of the van der Waals (vdW) equation and show that this equation describes accurately the BH phase transition. Based on the Lennard- Jones (LJ) potential we establish the modified LJ force which is compatible with this vdW equation. Of particular interest, in the first time we find that this force can be always written as the sum of the topological force, created by the topological charge, and the electrostatic force, created by charged conducting micro-sphere with definite radius. Then the phase transition of BH is totally controlled by these forces. In the process of phase transition from small to large BHs the sum of these forces changes from repulsive to attractive forces and this behavior is supported by the scalar curvature of the thermodynamic geometry. Combining these properties, we arrive at the physical picture of the BH molecules: they behave like charged conducting micro-spheres which bear topological charge. It necessarily to remark that although our intermolecular force is better than the one obtained recently in [29], it remains an approximate force.
{"title":"Towards the intermolecular force in charged AdS black hole","authors":"Van Quyet Hoang, Huu Phat Tran, Tuan Anh Nguyen","doi":"10.53747/nst.v12i2.376","DOIUrl":"https://doi.org/10.53747/nst.v12i2.376","url":null,"abstract":"In this paper we attempt to find the intermolecular force of charged AdS black holes (BH). We first write the equation of state of BH in the form of the van der Waals (vdW) equation and show that this equation describes accurately the BH phase transition. Based on the Lennard- Jones (LJ) potential we establish the modified LJ force which is compatible with this vdW equation. Of particular interest, in the first time we find that this force can be always written as the sum of the topological force, created by the topological charge, and the electrostatic force, created by charged conducting micro-sphere with definite radius. Then the phase transition of BH is totally controlled by these forces. In the process of phase transition from small to large BHs the sum of these forces changes from repulsive to attractive forces and this behavior is supported by the scalar curvature of the thermodynamic geometry. Combining these properties, we arrive at the physical picture of the BH molecules: they behave like charged conducting micro-spheres which bear topological charge. It necessarily to remark that although our intermolecular force is better than the one obtained recently in [29], it remains an approximate force.","PeriodicalId":19445,"journal":{"name":"Nuclear Science and Technology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-11-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139241412","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This report presents the process of calculating, designing and manufacturing a box-type mixer-settler system used for rare earth solvent extraction process on laboratory scale. The basic design parameters of the mixer-settler were calculated from two-phase flow rates, the contacting phase ratio and mixing time in mixer, the phase separation time in settler, the densities, and the viscosities of two phases. A detailed design of a 20-stages mixer-settler system based on established calculation results. The dimension design of mixer-settler includes the dimension definition of effective volume, the structure, the size of the mixer and settler chambers, the structural dimension of various phase openings and their location, and the impeller design. A mixer-settler system was built based on design parameters. This system is used for rare earth solvent extraction process on the laboratory scale.
{"title":"Calculation, design and manufacture of system box-type mixer-settler used in rare earth solvent extraction process at laboratory scale","authors":"Tùng Nguyễn Văn, Dinh Viet Nguyen, Quang Huy Ngo, Thi Lien Nguyen, Cong Trinh Bui, Xuan Dinh Luu","doi":"10.53747/nst.v12i2.346","DOIUrl":"https://doi.org/10.53747/nst.v12i2.346","url":null,"abstract":"This report presents the process of calculating, designing and manufacturing a box-type mixer-settler system used for rare earth solvent extraction process on laboratory scale. The basic design parameters of the mixer-settler were calculated from two-phase flow rates, the contacting phase ratio and mixing time in mixer, the phase separation time in settler, the densities, and the viscosities of two phases. A detailed design of a 20-stages mixer-settler system based on established calculation results. The dimension design of mixer-settler includes the dimension definition of effective volume, the structure, the size of the mixer and settler chambers, the structural dimension of various phase openings and their location, and the impeller design. A mixer-settler system was built based on design parameters. This system is used for rare earth solvent extraction process on the laboratory scale.","PeriodicalId":19445,"journal":{"name":"Nuclear Science and Technology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-11-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139238897","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This paper investigates the performance of genetic algorithm (GA) with improved selection techniques, i.e. Tournament and Roulette Wheel, applied to in-core fuel management of the Dalat nuclear research reactor (DNRR). Numerical calculations have been performed based on the DNRR core with 100 HEU fuel bundles. The optimal fitness function was chosen to maximize the keff and minimize the power peaking factor. The statistical analysis using Mann-Whitney test shows that the performance of GA with Tournament selection is advantageous over the Roulette Wheel selection in the ICFM problem of the DNRR. The optimal core configurations obtained with the improved GA methods have the keff values greater by about 500 pcm, and the PPF lower by about 4.0% compared to the reference core.
{"title":"Improved Genetic algorithm for fuel loading optimization of the DNRR with HEU fuel","authors":"Giang T. T. Phan, Hoai Nam Tran, Q. Do","doi":"10.53747/nst.v12i2.337","DOIUrl":"https://doi.org/10.53747/nst.v12i2.337","url":null,"abstract":"This paper investigates the performance of genetic algorithm (GA) with improved selection techniques, i.e. Tournament and Roulette Wheel, applied to in-core fuel management of the Dalat nuclear research reactor (DNRR). Numerical calculations have been performed based on the DNRR core with 100 HEU fuel bundles. The optimal fitness function was chosen to maximize the keff and minimize the power peaking factor. The statistical analysis using Mann-Whitney test shows that the performance of GA with Tournament selection is advantageous over the Roulette Wheel selection in the ICFM problem of the DNRR. The optimal core configurations obtained with the improved GA methods have the keff values greater by about 500 pcm, and the PPF lower by about 4.0% compared to the reference core.","PeriodicalId":19445,"journal":{"name":"Nuclear Science and Technology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-11-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139239842","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We study possible patterns of phase transitions at finite temperature in the charged AdS black holes (BHs). It is shown that in corresponding to standard pairs of conjugate thermodynamic variables charged AdS black holes contains either critical phenomena or interesting phase behaviour: a) for volume vs. pressure (V, P) a first order phase transition occurs similar to the van der Waals like from liquid to gas; b) for electric potential vs. charge (Phi, Q) a first order phase transition associated with the electric charge instability. The distinction between them is characterized by the behaviors of the phase diagrams, the phase transition regions, the latent heats, the coexistence lines and the scalar curvatures associating with different Riemann spaces established in BH thermodynamic geometry approach. We conjecture that this scenario could become realistic for all other black holes.
{"title":"Phase Transition in Conjugate Planes of Charged AdS Black Hole","authors":"Van Quyet Hoang, Tuan Anh Nguyen, Huu Phat Tran","doi":"10.53747/nst.v12i2.382","DOIUrl":"https://doi.org/10.53747/nst.v12i2.382","url":null,"abstract":"We study possible patterns of phase transitions at finite temperature in the charged AdS black holes (BHs). It is shown that in corresponding to standard pairs of conjugate thermodynamic variables charged AdS black holes contains either critical phenomena or interesting phase behaviour: a) for volume vs. pressure (V, P) a first order phase transition occurs similar to the van der Waals like from liquid to gas; b) for electric potential vs. charge (Phi, Q) a first order phase transition associated with the electric charge instability. The distinction between them is characterized by the behaviors of the phase diagrams, the phase transition regions, the latent heats, the coexistence lines and the scalar curvatures associating with different Riemann spaces established in BH thermodynamic geometry approach. We conjecture that this scenario could become realistic for all other black holes.","PeriodicalId":19445,"journal":{"name":"Nuclear Science and Technology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-11-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139240069","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Hoang Minh Le, Quang Vuong Le, T. Tran, Van-Tao Chau
This investigation aims to compare the full energy peak efficiencies in the energy range of 46-1836 keV on a type-p coaxial HPGe and estimate the coincidence summing factor for the case of Marinelli Beaker samples used by two general Monte-Carlo simulation software MCNP and PENELOPE. The radioactive nuclides used in determining the coincidence summing factor include 22Na, 60Co, 88Y, 133Ba, 134Cs, 154Eu, and 208Tl, which are prepared in HCl 2M solution and contained in a Marinelli beaker with the source’s volume of 3000 ml. The results demonstrate there is a good agreement between the two simulation software with an average discrepancy of 1.3%. On the other hand, the simulation coincidence summing factor values are also compared with the results from the calculating software ETNA with an average discrepancy of approximately 3.1%.
{"title":"Evaluating coincidence summing factor using marinelli beaker on coaxial HPGe detector by Monte Carlo simulation and calculating","authors":"Hoang Minh Le, Quang Vuong Le, T. Tran, Van-Tao Chau","doi":"10.53747/nst.v12i1.336","DOIUrl":"https://doi.org/10.53747/nst.v12i1.336","url":null,"abstract":"This investigation aims to compare the full energy peak efficiencies in the energy range of 46-1836 keV on a type-p coaxial HPGe and estimate the coincidence summing factor for the case of Marinelli Beaker samples used by two general Monte-Carlo simulation software MCNP and PENELOPE. The radioactive nuclides used in determining the coincidence summing factor include 22Na, 60Co, 88Y, 133Ba, 134Cs, 154Eu, and 208Tl, which are prepared in HCl 2M solution and contained in a Marinelli beaker with the source’s volume of 3000 ml. The results demonstrate there is a good agreement between the two simulation software with an average discrepancy of 1.3%. On the other hand, the simulation coincidence summing factor values are also compared with the results from the calculating software ETNA with an average discrepancy of approximately 3.1%.","PeriodicalId":19445,"journal":{"name":"Nuclear Science and Technology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-01-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84925434","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Thi-Mong-Tham Vo, Trong-Ngo Nguyen, Q. Tran, X. T. Le, Minh-Đao Nguyen, Quang-Trung Phan, Thi Huong Lan Nguyen, Ngoc Thien Bui
The activity concentrations of naturally occurring radionuclides 226Ra, 232Th, and 238U were determined in marine sediments, seawaters and seafood along the Gulf of Vietnam to establish baseline data for future environmental monitoring at a surface water depth of 0–3 cm. The concentration of uranium, thorium and radium were determined using a low background gamma spectrum as well as activity ofy of 238U(214Bi), 232Th(228Ac) and 226Ra. The mean radioactivity concentrations of 226Ra, 232Th, and 238U were found to be 8.59 ± 0.54, 1.31 ± 0.15, and 6.91 ± 0.64 Bq m−3, respectively, in seawater samples and 32.96 ± 1.90, 37.64 ± 1.91, and 39.28 ± 1.96 Bq kg−1, respectively, in marine sediments, 0.21 ± 0.03, 0.69 ± 0.11, and 0.19 ± 0.03 Bq kg−1, respectively, in fish samples and 0.23 ± 0.041, 0.41 ± 0.06, and 0.31 ± 0.06 Bq kg−1, respectively, in clam samples. The radioactivity concentrations in seawater are higher than those in sediment and compared with those reported in other countries. The mean values of distribution coefficient (L/kg) is 0.53, 0.13, and 0.23, respectively, in fish samples and 0.19, 0.16 and 0.13, respectively, in clam samples at Hai Phong, Quang Ninh and Ha Tinh. Moreover, the ecological dose at Hai Phong, Quang Ninh and Ha Tinh are 0.03, 0.02 and 0.02 µGy h−1, respectively, in fish and 0.02, 0.03, and 0.03 µGy h−1, respectively, in clams and the mean human’s seafood consumers dose rate is 1.13×10-6 Sv/yrs. Results were discussed and compared with those reported in similar studies and with internationally recommended values within limits recommended by UNSCEAR.
在越南湾沿岸的海洋沉积物、海水和海产品中测定了天然存在的放射性核素226Ra、232Th和238U的活度浓度，为今后在0-3厘米的地表水深度进行环境监测建立基线数据。铀、钍和镭的浓度是用低本底伽马谱以及238U(214Bi)、232Th(228Ac)和226Ra的活度来测定的。海水样品中226Ra、232Th和238U的平均放射性浓度分别为8.59±0.54、1.31±0.15和6.91±0.64 Bq m−3，海洋沉积物中226Ra、232Th和238U的平均放射性浓度分别为32.96±1.90、37.64±1.91和39.28±1.96 Bq kg−1，鱼类样品中226Ra、232Th和238U的平均放射性浓度分别为0.21±0.03、0.69±0.11和0.19±0.03 Bq kg−1，蛤蜊样品中226Ra、232Th和238U的平均放射性浓度分别为0.23±0.041、0.41±0.06和0.31±0.06 Bq kg−1。海水中的放射性浓度高于沉积物中的放射性浓度，也高于其他国家报告的放射性浓度。在海防、广宁和河静，鱼类样本的分布系数(L/kg)均值分别为0.53、0.13和0.23，蛤类样本的分布系数(L/kg)均值分别为0.19、0.16和0.13。此外，海防、广宁和河静的生态剂量分别为鱼类0.03、0.02和0.02µGy h - 1，蛤的生态剂量分别为0.02、0.03和0.03µGy h - 1，人类海鲜消费平均剂量率为1.13×10-6 Sv/年。对结果进行了讨论，并与类似研究报告的结果以及与科委会建议的范围内的国际推荐值进行了比较。
{"title":"Assessing the radiological risks associated with primarily natural radioactivities of coastal seawater in northen Vietnam using the Erica software","authors":"Thi-Mong-Tham Vo, Trong-Ngo Nguyen, Q. Tran, X. T. Le, Minh-Đao Nguyen, Quang-Trung Phan, Thi Huong Lan Nguyen, Ngoc Thien Bui","doi":"10.53747/nst.v12i1.340","DOIUrl":"https://doi.org/10.53747/nst.v12i1.340","url":null,"abstract":"The activity concentrations of naturally occurring radionuclides 226Ra, 232Th, and 238U were determined in marine sediments, seawaters and seafood along the Gulf of Vietnam to establish baseline data for future environmental monitoring at a surface water depth of 0–3 cm. The concentration of uranium, thorium and radium were determined using a low background gamma spectrum as well as activity ofy of 238U(214Bi), 232Th(228Ac) and 226Ra. The mean radioactivity concentrations of 226Ra, 232Th, and 238U were found to be 8.59 ± 0.54, 1.31 ± 0.15, and 6.91 ± 0.64 Bq m−3, respectively, in seawater samples and 32.96 ± 1.90, 37.64 ± 1.91, and 39.28 ± 1.96 Bq kg−1, respectively, in marine sediments, 0.21 ± 0.03, 0.69 ± 0.11, and 0.19 ± 0.03 Bq kg−1, respectively, in fish samples and 0.23 ± 0.041, 0.41 ± 0.06, and 0.31 ± 0.06 Bq kg−1, respectively, in clam samples. The radioactivity concentrations in seawater are higher than those in sediment and compared with those reported in other countries. The mean values of distribution coefficient (L/kg) is 0.53, 0.13, and 0.23, respectively, in fish samples and 0.19, 0.16 and 0.13, respectively, in clam samples at Hai Phong, Quang Ninh and Ha Tinh. Moreover, the ecological dose at Hai Phong, Quang Ninh and Ha Tinh are 0.03, 0.02 and 0.02 µGy h−1, respectively, in fish and 0.02, 0.03, and 0.03 µGy h−1, respectively, in clams and the mean human’s seafood consumers dose rate is 1.13×10-6 Sv/yrs. Results were discussed and compared with those reported in similar studies and with internationally recommended values within limits recommended by UNSCEAR.","PeriodicalId":19445,"journal":{"name":"Nuclear Science and Technology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-01-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83024632","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The accurate prediction of void fraction parameter in subcooled boiling flow is very important for nuclear safety since it has significant influences on the mass flow rate, the onset of two-phase flow instability, and the heat transfer characteristics in a nuclear reactor core. Many different models and empirical correlations have been established over a variety of input conditions; however, this classical approach could lead to unsatisfactory prediction due to the uncertainties of model parameter and model forms. To cope with these limitations, Artificial Neural Network (ANN) is a powerful machine learning tool for modeling and solving non-linear and complicated physical problems. Therefore, this work is aim at developing an ANN-based model to predict the local void fraction of subcooled boiling flows. The comparison results of the performance between the ANN-based model and empirical correlations for the void fraction prediction of subcooled boiling in vertical upward channel showed the potential use of ANN-based model in the Computational Fluid Dynamics (CFD) codes to accurately simulate the subcooled boiling phenomena.
{"title":"Performance Comparison of ANN-Based Model and Empirical Correlations for Void Fraction Prediction of Subcooled Boiling Flow in Vertical Upward Channel","authors":"Ngoc Dat Nguyen, Van Thai Nguyen","doi":"10.53747/nst.v11i4.335","DOIUrl":"https://doi.org/10.53747/nst.v11i4.335","url":null,"abstract":"The accurate prediction of void fraction parameter in subcooled boiling flow is very important for nuclear safety since it has significant influences on the mass flow rate, the onset of two-phase flow instability, and the heat transfer characteristics in a nuclear reactor core. Many different models and empirical correlations have been established over a variety of input conditions; however, this classical approach could lead to unsatisfactory prediction due to the uncertainties of model parameter and model forms. To cope with these limitations, Artificial Neural Network (ANN) is a powerful machine learning tool for modeling and solving non-linear and complicated physical problems. Therefore, this work is aim at developing an ANN-based model to predict the local void fraction of subcooled boiling flows. The comparison results of the performance between the ANN-based model and empirical correlations for the void fraction prediction of subcooled boiling in vertical upward channel showed the potential use of ANN-based model in the Computational Fluid Dynamics (CFD) codes to accurately simulate the subcooled boiling phenomena.","PeriodicalId":19445,"journal":{"name":"Nuclear Science and Technology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-01-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91109000","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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