bluuebunny/crossref_metadata_2025_split huggingface dataset:
Analytical Study of Matching of Dual Compressor Modules With Turbine for Small Modular Reactors
Authors: Lu Frank K. , Jayamani Ananthkumar , Kim Daejong , Bolin John , Curiac Radu , Choi Hangbok 
Published: November 2024

Abstract
An analytical study of a power conversion unit consisting of a dual compressor and a turbine operating on a closed Brayton cycle with helium is presented. The turbomachinery was a constant hub design with two compressor modules and a turbine module. The design code included the capability to perform sweeps of input parameters such as the polytropic efficiency or loss coefficient, degree of reaction, etc. It is required that the pressure rise of each of the two compressor modules be approximately equal. An optimization procedure for the low- and high-pressure compressors resulted in both of them having seven stages. The performance for each of the compressor stages is almost identical. Another optimization procedure for the turbine yielded six stages. Likewise, the performance for each of the turbine stages is almost identical. Performance maps were developed individually for each of the compressor modules and the turbine. Mathematical constraints based on problem physics were used in conjunction with the component maps to trace turbomachinery operating points. Results show that the low-pressure compressor operates close to the surge line. It is recommended to implement a recirculation path to avoid possible surge in compressor.
Using Radius of Gyration in Order to Determine Surrogate Mechanical Properties of a Porous Structure
Authors: Shiman Oksana V. , Gaudet Michel 
Published: November 2024

Abstract
Advances in additive manufacturing have now made printing very fine design features possible, giving rise to the possibility of incorporating a porous structure within a component to act as a thermal barrier. The model of such a component may be simplified during finite element analysis by replacing the topographically complex porous structure with that of a homogeneous material having surrogate material properties equivalent to those of the porous structure. Determining changes in length within a porous structure for the purpose of calculating strain presents a challenge. Due to the nature of the porous structure, non-uniform displacements are possible, introducing difficulty in assessing aggregate displacements. The possibility of using the radius of gyration as a measure of displacements within a structure is explored in the present study. The positions of finite element meshing nodes were used to calculate mass distribution within unit cells of a gyroid structure, and from this, a radius of gyration was derived. Unit strain, and consequently Young’s modulus and Poisson’s ratio were obtained for the porous structure from the changes in radii of gyration, which can be used to describe an equivalent bulk material. Excellent agreement was obtained when directly comparing the elastic response of a gyroid cluster and equivalent homogeneous material under identical loading conditions.
Study on Power Regulation Methods of Microreactor Coupled With Closed Helium Gas Turbine Direct Cycle
Authors: Geng Xuyao , Wang Jie 
Published: November 2024

Abstract
Microreactor is a class of rapidly developing small advanced reactor. It has many advantages: mobility and transport ability, resilience, and independence from the grid, as well as its capacity for long refueling intervals. The microreactor utilizing high-temperature gas-cooled reactor technology has inherent safety. By coupling microreactor with the helium turbine direct cycle power generation system, it can operate at high temperature. Therefore, the microreactor coupled with closed helium gas turbine direct cycle (MR-GT) has broad prospects for development. In this paper, the mathematical model of the MR-GT system is established to study the dynamic characteristics. Based on the conservation equations of mass, momentum and energy, the thermo-hydraulic model of power conversion system including heat transfer components and turbomachinery is established. The transient reactor power is calculated by the point reactor neutron kinetics equations. Finally, the lumped parameter nonlinear system model of the MR-GT is established by coupling the above models. The Modelica simulation language is used to solve these nonlinear ordinary differential and algebraic equations. The dynamic characteristics of the MR-GT system under the conditions of reactivity insertion and helium inventory regulation are studied. The results show that the system power can be independently adjusted within a certain range by changing the reactivity or helium inventory. By synergistically regulating the reactor reactivity and helium inventory, the temperature and efficiency of the MR-GT system can be kept basically unchanged, which is an ideal power regulation method.
Numerical Investigation on the Thermal-Hydraulic and FIV Characteristics in LBE-Cooled Helical Cruciform Fuel and Wire-Wrapped Fuel
Authors: Zhang Qi , Wang Haoyu , Cao Junxian , Li Yuanming , Li Chenxi , Liu Zhenhai 
Published: November 2024

Abstract
The lead bismuth eutectic (LBE) cooled fast reactor in one of the General 4 advanced reactors, which plays significant role in the nuclear fuel cycle. In the recent years, the wire-wrapped fuel with four wires surrounds the cylindrical fuel is developed and promoted, which may be accept by the LBE-cooled fast reactor. The helical cruciform fuel of the Lightbridge corporation has similar geometrical features with the wire-wrapped fuel. The cross-section of helical cruciform fuel consists of the convex blades and the concave elbows, and the cross-section is rotated around the axis. The blade and elbow of helical cruciform fuel function as the wires while they are part of the nuclear fuel. In the present work, the comparison on the thermal-hydraulic and flow-induced vibration (FIV) characteristics of the helical cruciform fuel and wire-wrapped fuel is carried out by numerical simulation. The fluid-structure interaction is solved by the coupling between the fluid and solid domains, and the transient turbulence fluctuation is solved by large eddy simulation (LES). The results show that the convective heat transfer is enhanced by the spiral structures even though the hot spot phenomenon is caused simultaneously. The hot spot temperature of the helical cruciform fuel is larger than the wire-wrapped fuel duo to the non-uniform distributed heat flux. As the coolant in the flow channel is blocked by the blades and wires, the directional transverse flow is generated and thus the transverse mixing is enhanced. The one-way mixing with opposite direction occurs in the two sides of the single rod. There are similarities in the FIV characteristics for the spiral shaped fuels. The maximum vibration displacement and dominant vibration frequency of the helical cruciform fuel and wire-wrapped fuel are almost the same.
Development of Thermal-Hydraulic and Safety Analysis Code for a Heat Pipe Cooled Reactor
Authors: Jiao Guanghui , Xia Genglei , Zhou Tao , Wang Jianjun 
Published: November 2024

Abstract
Heat pipe cooled reactors have attracted attention as a promising option for nuclear power generation in space and deep-sea applications due to their simple design, scalability, safety and reliability. Although various models of heat pipe-cooled reactors have been proposed, there remains a gap in rapid and efficient thermal-hydraulic programs for evaluating the operational characteristics and safety of these reactors. In this study, a transient neutron-thermal coupling code was developed to assess the transient characteristics of the core of a heat pipe cooled reactor. This code includes a neutron physics model, a heat pipe model, and a core heat transfer model, and it was verified using reference data and experimental results. Additionally, the code was employed to analyze the operational characteristics of typical accidents, such as reactivity insertion accidents, heat pipe failure, and loss of heat sink incidents. In the reactivity insertion accident, the reactor power stabilized to a new steady state after a period. In the accident of heat pipe failure, the heat from the failed fuel assembly was effectively transferred through adjacent heat pipes. During a loss of heat sink accident, the reactor core safely shut down due to negative feedback, with an initial spike in core temperature followed by a decrease. Throughout all transient processes in these accidents, the fuel pin temperatures maintained a significant safety margin, demonstrating the reactor’s strong safety performance in various accident scenarios. This code thus provides an effective tool for the design and safety analysis of heat pipe cooled reactors.
Design and Experimental Verification of Passive Residual Heat Removal System for a Alkali-Metal Heat Pipe Cooled Reactor
Authors: Wu Hexin , Gou Junli , Wang Ruifeng , Yuan Leqi , Shan Jianqiang 
Published: November 2024

Abstract
The high-temperature heat pipe (HTHP) cooled reactor has the advantages of compact, safety and reliability, rendering it a promising technology for application in Unmanned Underwater Vehicles (UUVs). In this paper, a Passive Residual Heat Removal (PRHR) system is designed for a marine nuclear power plant proposed by the Chinese Academy of Engineering Physics (CAEP). The PRHR efficiently utilizes the space of the adiabatic section of the heat pipe bundle as Emergency Cooling Chamber (ECC) to establish natural circulation. The CFD model of the ECC was established and the geometric parameters of the system were optimized. The results indicate that a hexagonal baffle around the adiabatic section of heat pipe bundle is superior to no baffles. The inlet and outlet widths of the hexagonal baffle has a negligible impact on the heat removal power during the natural circulation process. Furthermore, the analysis shows that the residual heat removal power requirement can be conservatively met when the axial length of the ECC is 100.0 mm. Subsequent experimental investigations were conducted to analyze the characteristics of heat removal power and the wall temperature distribution of the heat pipe under various cooling conditions. The results reveal a logarithmic rise in heat removal capacity with the mass flow rate, a linear decline in cooling water temperature with increasing inlet temperature, and a negligible impact of pressure fluctuations on heat removal capacity. Furthermore, the mass flow rate, temperature, and pressure of the cooling water demonstrate minimal effects on the temperature of the heat pipe wall.
Comparative Study of Deep Learning Models for Accidents Classification in NPP: Emphasizing Transparency and Performance
Authors: Najar Merouane , Wang He 
Published: November 2024

Abstract
The nuclear power plant (NPP) plays a crucial role in providing clean energy, significantly contributing to mitigating global warming. However, this advantage is accompanied by public concerns regarding potential accidents. The imperative for a robust safety system has led to the exploration of artificial intelligence (AI) integration in NPP to minimize human error and enhance safety efficiency during reactor accidents. This research conducts a comparative study between two deep learning (DL) models to classify five accidents based on algorithm performance and transparency. These accidents include Loss of Coolant Accident (LOCA), Loss of On-site Power (LOOP), Loss of Flow Accident (LOFA), Steam Generator Tube Rupture (SGTR), and Feed Water Line Break (FWLB). The necessary data was collected using open data from Personal Computer Transient Analyzer (PCTRAN) software, subsequently separated into two categories: digital and numerical. Image data is utilized for training Convolutional Neural Network (CNN), while quantitative data is employed for training Artificial Neural Network (ANN). Additionally, four metric parameters (Accuracy, Recall, F1-score, Precision) are used to evaluate the model’s performance. Finally, eXplainable Artificial Intelligence (XAI) techniques are employed through the use of the Shapley Additive Explanation (SHAP) package to provide the model’s output explainability.
The results show that within the two DL algorithms, CNN presents the best performance, demonstrating an excellent accuracy reaching 99.74 and requiring less time and a smaller dataset than ANN. Furthermore, the use of XAI explains the reasons behind the models’ decision-making process, leading to the establishment of trust in the algorithms’ results.
Advancement in Shielding Materials: Geant4 Simulation of Gamma Radiation With Polystyrene-Bismuth Oxide
Authors: Aminu Bashir Garba , Liu Yongkuo , Akhdar Hanan , Lawal Shamsuddeen 
Published: November 2024

Abstract
The selection of suitable materials for radiation shielding is of paramount importance in safeguarding individuals and the environment against the detrimental effects of ionizing radiation. As radiation-emitting technologies continue to expand across various domains, the meticulous assessment of appropriate shielding materials has become increasingly critical. This work has presented a comprehensive study on Polystyrene-bismuth oxide composites (PS-Bi2O3) within an energy range spanning from 100 to 2000 keV, containing different percentage compositions of bismuth oxide (Bi2O3). The primary objective is to explore the gamma mass attenuation μ/ρ and linear attenuation μ coefficients of these composites which lead to comprehensive evaluation of half-value layers of all the studied samples as it is very crucial parameter in finding the shielding ability of a material, while it encompassed various weight factors of bismuth oxide within the samples. This exploration has been carried out through the utilization of EpiXS and a Monte Carlo simulation-based toolkit, namely Geant4. The rationale for covering such a wide energy spectrum for gamma rays is to ensure applicability across a diverse range of scenarios, so that the findings can be useful in many different situations. These attenuation coefficients have been used to determine the half-value layers of each of the various samples. Additionally, the study involved a comparative analysis of the effective atomic numbers and effective electron densities obtained from the EpiXS results.
In summary, this research offered valuable insights by not only developing new and reliable shielding materials but also by thoroughly exploring the shielding characteristics of Polystyrene-bismuth oxide composites across a diverse range of energy levels and examining potential of its uses across that wide range of energy levels. The findings have the potential to inform the selection of effective shielding materials in various practical applications, ensuring enhanced radiation protection in different settings.
Multi-Objective Optimization Study of Nozzle Outlet Size Based on Atomization Performance
Authors: Qingshan Chen , Wang Mingjun , Tian Wenxi , Qiu Suizheng , Su Guanghui 
Published: November 2024

Abstract
The nozzle plays a significant role in the nuclear power plant’s safety and the reactor’s integrity. The structure of the nozzle directly affects the atomization performance, consequently impacting the pressure and temperature variations within the regulator. This study focuses on the single inlet pressure-swirl nozzle structure, employing the response surface optimization method to obtain the influence of nozzle outlet diameter, outlet length, and outlet chamfer on atomization performance. The optimization responses encompass droplet size, droplet uniformity, and atomizing cone angle, and Design-Expert software is utilized to optimize the design of the nozzle outlet size. Compared to the pre-optimization state, the optimized nozzle exhibited a 43.44% reduction in average droplet diameter, a 30.74% increase in atomization cone angle, and a 76.73% improvement in droplet uniformity.
Overview of Tritium-Resistant Performance of Heat Transfer Tube Materials in Reactors
Authors: Wu Mengjie , Zhou Ziling , Wang Yu , Qu Zhengzhe , Chen Jing , Xie Feng , Cao Jianzhu , Tong Jiejuan 
Published: November 2024

Abstract
Tritium, a radioactive hydrogen isotope widely distributed in fission and fusion reactors, has received considerable attention for its behavior within nuclear systems. As the sole barrier against tritium permeation from the primary to the secondary loop, the performance of heat transfer tubes in resisting tritium is extremely crucial. In future fusion reactors, where tritium serves as a fuel at higher concentrations and larger scales, its permeation issues will become even more challenging. Therefore, evaluating and developing heat transfer tube materials with high tritium resistance is paramount for advancing reactor high-temperature applications and ensuring their radiation safety.
This paper reviews the model of tritium permeation through heat transfer tubes from the primary to the secondary loop, using DT as an example. It then discusses the use and composition of common heat transfer tube materials in reactors, summarizes the tritium permeation rates, diffusion coefficients, and solubility at corresponding temperatures for different alloys, and analyzes the impact of Cr and Ni content on the tritium-resisting performance of alloys. After comparison, Hastelloy XR, F82H and Incoloy 800H are selected as three alloys with high tritium-resisting performance for use as reactor heat transfer tube materials. Finally, the paper provides feasible suggestions for preventing tritium permeation, hoping to offer valuable references for tritium control and management in both fission and fusion reactors.
Experimental Study of the Effect of Inclination Angle on the Heat Transfer Characteristics of Steam Condensation in the Vertical Tube
Authors: Liu Jiabao , Cao Xiaxin , Yang Peixun 
Published: November 2024

Abstract
The purpose of the experiment was to investigate the effect of inclination angle on steam condensation heat transfer characteristics for downward flow in a vertical tube at different mass fluxes. The inlet pressure of saturated steam was 0.2 MPa and the mass fluxes ranged from 20 to 60 kg·m−2·s−1. The experiment was conducted at a range of inclination angles between 0° to 25°. The results showed that with the variation of inclination angle, the flow patterns in the tube at the outlet of the condensate tube mainly showed three kinds of type, namely, annular wavy flow, semi-annular wavy flow and stratified wavy flow. Moreover, the heat transfer coefficient increased with the increase of the inclination angle, and the influence of the inclination angle on the heat transfer coefficient decreased with the increase of the mass fluxes. The effect of the inclination angle on the heat transfer coefficient increased as the vapor quality decreased. Comparing the heat transfer coefficients measured experimentally with the calculated values of the correlation equation of Shah (2016), the results showed that the precision of the predicted values of the relational equation of Shah for the heat transfer coefficients of condensation in the inclined tube was good enough.
Monte Carlo Simulation of Response of Beta-Delayed Neutron Inspection System for Fuel Cladding Damage
Authors: Zhang Weihua , Zhang Liguo , Cao Jianzhu 
Published: November 2024

Abstract
This work was aimed to design one novel device to monitor β-delayed neutron in the circuit coolant water. The response of β-delayed neutron inspection system was primarily simulated by PHITS Monte Carlo code including the pulse height spectrum, detection efficiency and time spectrum of neutron counters. The detection efficiencies (from 1 keV to 1 MeV) of two neutron monitors were respectively displayed as about 50% (12 He-3 counters) and about 30% (108 10B-coated counters). The beta monitor was designed as array of thin-slice plastic scintillators immersed in water to attain as large detection efficiency as possible. The simulated detection efficiency for beta particles (energy higher than 1 MeV) was more than 34%.
Temperature Field Rapid Estimation of Space Nuclear Thermionic Reactor Based on Reduced-Order Model
Authors: Liu Shuo , Wang Chenglong , Qiu Suizheng , Tian Wenxi , Su Guanghui 
Published: November 2024

Abstract
In order to overcome the shortcomings of Computational Fluid Dynamics (CFD), which needs to consume a lot of computational resources and time to obtain the flow field information. In this paper, a non-intrusive reduced-order model was developed based on the POD an BP neural network. Then the established ROM was applied in the temperature filed rapid estimation of the space thermionic reactor, TOPAZ-II. ANSYS Fluent are used to obtain the data snapshot samples of the temperature field of TOPAZ-II. Under the new operating conditions, the temperature field was rapidly reconstructed by training-completed ROM. The ROM was validated by comparing the ROM results with Fluent results. The maximum absolute error of temperature is 0.2 K with speed-up on the order 4.8 × 103. Therefore, the methodology in this paper provides a reference for real-time monitoring of the thermionic reactor operation in orbit.
Gas Leakage Test for Radioactive Materials Transport Package With Vibration
Authors: Sun Qian , Wang Pengyi , Chen Lei , Bai Juying , Jiao Limin , Wang Zhipeng , Zhuang Dajie , Sun Hongchao 
Published: November 2024

Abstract
Radioactive materials transport packages (RMTP) are the key equipments to ensure the safe transportation of radioactive materials, which can play a variety of important functions. Among them, the containment sealing function is an important safety requirement for RMTP containing radioactive contents such as gases and powders. The realization of the sealing for RMTP is not only to safeguard the quality of the contents and to prevent any reduction in the quantities of the contents. The leakage rate requirement should be determined at the design stage, which is as the criterion for judging the conformity of the sealing performance. And a suitable detection test method should be selected to carry out gas leakage test. Currently, gas leakage test for RMTP is mainly used to verify the sealing performance at the normal condition and the condition after tests required by IAEA SSR-6. However, the effects of different vibration conditions during transportation on the RMTP sealing performance are not taken into account. Therefore, the effects of vibration on the RMTP has been studied by experiment. Helium mass spectrometer leak detector and cladding inflation-gas detector method were used in the study. A scaled-down RMTP model and a small vibration test equipment were used carry out constant-frequency vibration tests. It was found that the cumulative effect of vibration causes the gas leakage rate increase for RMTP and it increases with the number of vibration tests.