bluuebunny/crossref_metadata_2025 huggingface dataset:
Analytical Study of Melt Spreading in Shallow Pool Observed in PULiMS-E10 Test Using MSPREAD Implemented With Molten Jet Quench Model
Authors: Kikuchi Wataru , Hotta Akitoshi , Ito Koetsu , Yugo Hiroaki , Shimizu Mamoru
Published: November 2024

The subject of this study is a numerical simulation of the melt spreading in a shallow pool using MSPREAD, a two-dimensional high-resolution melt spreading analysis code. The identified influential factors in under-water melt spreading are the heat transfer between the melt and the overlying water, melt-coolant interaction (MCI) caused by water confinement at the time of molten jet impingement, molten jet breakup into melt slugs, disperse of melt slugs and cooling by water recirculating inside the partially solidified debris bed. In particular, the above-mentioned MCI and the subsequent chain of phenomena were named “the molten jet quench” by the authors, and a numerical model was proposed and implemented in MSPREAD. In this model, the diameter of spherical melt slugs and the radius of the floor region where melt continues to be slugs can be given as the user inputs. The three sensitivity analysis cases were performed with varying these two inputs together with no quench cases based on the PULiMS-E10 test conducted by the Royal Institute of Technology. Comparison of the time histories of the spreading area, pool water temperature, 2D spreading shapes and post-test debris cross section indicated that the molten jet quench can explain short spreading distances, thicker solidified debris, and even higher pool water temperatures observed in PULiMS-E10.
Research on Typical Fault Prediction Model of the Reactor Coolant Pump Based on Multi-Information Fusion of GRU
Authors: Huaiming Cui , Chengxiao Kuang
Published: November 2024

According to the sensor type, measuring point distribution and acquisition frequency of the Reactor Coolant Pump (RCP) in the nuclear power plant, the typical failure mode of the key vulnerable parts of RCP is investigated and sorted out. Then, the simulation test bench of bearing and shaft seal components is set up respectively to simulate the operation of bearing and shaft seal components in several typical faults, and the multi-channel fault sample data is collected. In order to solve the problem of poor prediction accuracy and weak generalization ability of traditional neural network. Based on the above experimental data, a multi-information fusion prediction model of key signal of main pump based on gated circulation unit GRU is proposed in this paper. After testing the test set data, compared with the traditional deep learning algorithm, it is shown that the prediction model designed in this paper has the best prediction effect.
Researchers Understanding of the Possible Contribution of International Atomic Energy’s to the Launch of a National Nuclear Power Programme
Authors: Ala Ayodeji , Oluwafolakemi Ala
Published: November 2024

The continuous rise in global energy demand is a result of factors such as increasing globalization, increased access to technology, increasing world population, and rising standard of living. This study investigates the level of understanding of the role of the International Atomic Energy Agency among researchers involved in nuclear power programmes. The level of knowledge on the launching of a nuclear power programme is significantly related to the existence of a nuclear power plant in a country while the understanding of the IAEA milestone approach correlates with the knowledge of other nuclear technology applications in the country. These results show that research reactors and the wide application of nuclear technology in a country can contribute to understanding the critical issues associated with nuclear power programme development.
SAMPO-P Test Facility and Numerical Pretest
Authors: Guo Pengya , Yu Peng , Quan Fengyang , Li Wei , Pei Jie , Yuan Yidan , Yu Jiyang , Ma Weimin
Published: November 2024

The in-vessel retention (IVR) strategy was developed to retain the corium within the reactor pressure vessel (RPV) to prevent the release of radioactive products during severe accidents. However, the RASPLAV study reveals the potential formation of a two-layer melt pool pattern, wherein the heat flux in the top metal layer significantly exceeds the average heat flux density, posing a considerable threat to the integrity of the pressure vessel and the success of the IVR strategy. Previous studies on stratified melt pools have primarily concentrated on the natural convection behavior within the melt pool using scaled facilities. To better understand the thermal behavior of the two-layer melt pool heat transfer, this study constructed a 1:1 ratio-sized 2D stratified melt pool experiment facility ‘SAMPO-P’ based on the HPR1000 RPV lower head. The numerical pre-test simulations are conducted using in-house code to help determine the experimental conditions and test matrix. The simulants of the oxide layer and metal layer were Chlorine salt and Al-Mg alloy. The results indicate that as the heating power increases from 180 kW to 255 kW, the temperature and heat flux increase while the thickness of the bottom crust decreases with no significant heat flux peak in the metal layer observed. The first experiment is scheduled for this year. The experimental results are expected to provide essential insights into understanding the flow and heat transfer characteristics and further improve the numerical model in future research.
A Liquid Metal Subchannel Code Used in Ocean Conditions and Study the Heat Transfer Characteristics in Rod Bundle of Reactor Core
Authors: Yin Yuanyuan , Han Bin , Zhu Xiaoliang , Qi Siwei , Liu Shenghui , Xing Tianyang , Yang Bao-Wen , Liu Aiguo
Published: November 2024

In this study, a thermal hydraulic ocean version subchannel analysis code is developed for liquid metal reactor core analysis based on the theoretical model of ocean conditions. In the developing process, the ocean conditions are divided into heaving, rolling and pitching conditions. During the development of the program, it is found that the research on the characteristics of flow resistance and heat transfer mechanism under ocean conditions is not mature, the theoretical models are not perfect, and there is no widely recognized empirical relationship under ocean conditions. The original empirical model is still used in the first version of the program. Furthermore, the verification and validation of the subchannel program is carried out by comparing the results of experimental data. The effects of geometric parameters such as rod Pitch to Diameter ratio P/D, Rod to Wall gap (RTW) are studied. In addition, the boundary conditions of inlet mass flow on the flow and heat transfer under ocean conditions are investigated. The effect of rolling motion on different coolants including liquid meal and water are discussed under ocean conditions. The newly developed subchannel analysis code can well complete the thermal and hydraulic calculation of liquid metal cooled fuel assemblies under ocean conditions, and can provide support for the design and thermal and hydraulic analysis of reactor in ocean environment.
Study on the PSA Application in Emergency Operating Procedure Development
Authors: Ma Chao , Feng Churan , Du Jinyan , Yang Jian
Published: November 2024

With the development of PSA technology, more and more PSA technology is being applied in various design fields during the design process of nuclear power plants. The emergency operating procedures for nuclear power plants are an important part of accident response and processing. From previous PSA analysis results, it can also be seen that emergency operating procedures play an important role in ensuring the safety of nuclear power plants. The emergency operating procedures are in line with the design of nuclear power plants. The power plant operating conditions considered in the design of nuclear power plants need to be reflected in the emergency operating procedures, and the measures for responding to nuclear power plant accidents need to be considered in the accident. The emergency operating procedures should cover the main event sequences of the power plant. In addition to relying on past engineering practices, PSA can provide a more systematic analysis of event sequences, and provide support for the development of emergency operating procedures based on the likelihood of accidents and event sequences occurring, as well as the overall risk of the power plant. This article combines the technical characteristics of PSA and applies PSA technology to the process of preparing emergency operating procedures for nuclear power plants. It provides a general method and beneficial insights for PSA to support the preparation of emergency operating procedures, making them more systematic, complete, and effective. PSA provides a systematic analysis from potential accidents to the final handling of accidents, and supports emergency operating procedures in the following two aspects: the conditions considered by emergency operating procedures (including design basic conditions and design extension conditions); Is the emergency operating procedure sufficient and effective in guiding the actions of important operators, especially in operator actions under extension operating conditions.
Neutronics/Thermal-Hydraulics Coupling Simulation Using JAMPAN in a Single BWR Fuel Assembly
Authors: Kamiya Tomohiro , Nagatake Taku , Ono Ayako , Tada Kenichi , Kondo Ryoichi , Nagaya Yasunobu , Yoshida Hiroyuki
Published: November 2024

We have aimed to realize high-fidelity neutronics/thermal-hydraulics coupling simulation to provide simulation results that can be used as validation data for reactor analysis codes. We have developed a multi-physics platform, JAMPAN, to conduct neutronics/thermal-hydraulics coupling simulation by connecting independent codes. It is required to reduce empirical correlations as far as possible to perform high-fidelity neutronics/thermal-hydraulics coupling simulation. Hence, a continuous energy Monte Carlo code MVP is adopted as a neutronic analysis code, and a detailed and phenomenological numerical simulation code JUPITER is adopted as a thermal-hydraulics analysis code. Our simulation target is a single BWR fuel assembly. Hence, the simulation results need to reproduce the varying heat generation owing to the varying void fraction. Therefore, we carried out MVP/JUPITER coupling simulation in a 8 × 8 single fuel assembly of BWR and confirmed that the void fraction and heat generation distribution are reasonable qualitatively. Furthermore, it is required to clarify the effect of the parameters of the coupling simulation on the results, and the time interval is one of the coupling parameters to improve the reliability of the simulations. We carried out MVP/JUPITER coupling simulation in a 2 × 2 fuel pin system using the multi-physics platform JAMPAN to investigate the effect of the time interval on the results. A 2 × 2 fuel pin system, which is the smaller unit of the actual single fuel assembly for a BWR, is adopted as a simulation target to effectively investigate the effect. It is found that the effect of the time interval on the simulation results is small.
Status of the Light-Water, Small, Modular Reactors Research at Oregon State University
Authors: Gutowska Izabela , Howard Trevor Kent , Wu Qiao , Woods Brian G.
Published: November 2024

This paper provides a comprehensive overview of the ongoing research endeavors conducted at Oregon State University School of Nuclear Science and Engineering (OSU NSE) in the field of Light-Water, Small, Modular Reactors (LW-SMR). Included in this paper is a thorough exposition of the integral testing activities carried out at the Multi-Application, Small, Light-Water, Reactor (MASLWR) facility, including both the methodologies employed and the outcomes obtained. The test facility can operate at pressure of 11.4 MPa and a temperature of 590 K. It serves as an integral test facility, with all components designed at a 1/3 scale height and a 1/254.7 volume scale in reference to the NuScale module. The facility operates in compliance with the NQA-1 program and has been instrumental in supporting NuScale’s licensing process and the validation of TH (thermal-hydraulic) codes. This paper further expounds on the present operational status of the facility and delineates upcoming plans. Beyond the experimental capabilities, additional attention is directed towards an explication of the research capabilities intrinsic to the Nuscale Simulator control room, housed within the OSU Energy Exploration (E2) Center. Finally, the paper delves into an exploration of ongoing research concerning the Dynamical System Scaling (DSS) of Small Modular Reactors (SMRs).

This paper serves as a consolidated resource offering insight into the multifaceted aspects of LW-SMR research conducted at Oregon State University, encompassing integral testing, facility status, control room research capabilities, and the DSS endeavors related to SMRs.
Effects of Mixed Inert Gases on Design of Centrifugal Compressors for Space Nuclear Reactor
Authors: Xu Risheng , Ma Wenkui , Ye Ping , Zhao Gang , Yang Xiaoyong
Published: November 2024

The aerospace industry considers nuclear reactor as the prime candidate to extend mission durations and enhance the energy supply for spacecraft. Among the power conversion systems for space reactors, the direct closed Brayton cycle stands out for its compactness, lightness, safety, and high power density, making it exceptionally well-suited to these applications. Centrifugal compressor is a key component of the Brayton cycle, whose performance is pivotal in the system efficiency. Researches on compressors utilizing inert gases has predominantly concentrated on helium-xenon mixtures, leaving other inert gas combinations less explored. Moreover, the influence of inert gas mixture proportions on compressor design has not been adequately addressed in the literature. To fill this research gap, this paper established models of the inert gas mixtures properties and design of centrifugal compressors, and investigated the effects of inert gas mixtures, including helium-argon and helium-neon mixtures, on performance and geometric parameters of the centrifugal compressor. The results indicated that helium-argon or helium-neon mixtures working fluid could significantly reduce the number of compressor stages, thus potentially minimizing the compressor’s volume and mass compared to pure helium working fluid. The increase in the molar mass of the gas mixture decreased the rotational speed and maximum circumferential velocity of the compressor and increase the mass flow rate and the Mach number at the exit of the final-stage impeller. This study provides a reference for the selection of working fluids in space reactor Brayton cycles and the design of centrifugal compressors.
A Coordinated Control Strategy for NHR200-II Under Load Rejection Condition
Authors: Huang Canxing , Xiong Huasheng , Dong Zhe , Li Boyuan , Zhou Shuqiao
Published: November 2024

In recent years, the safety and stability of power plant operations have attracted more and more attention. As a clean and safe energy, nuclear power is up-and-coming in China. However, external interruption is hard to avoid and usually causes negative consequences. The load rejection condition may occur in nuclear power plants due to environmental influences, external power grid shock, or failure. This paper mainly discussed the load rejection process of NHR200-II, one of the steam generator outlet valves closed unexpectedly and the reactor load changed from 100% to 50%. The load rejection condition was simulated in MATLAB SIMULINK and analyzed in detail. A control strategy for this abnormal condition was proposed and a cascade control over the steam pressure control loop was introduced. This control strategy was validated by conducting simulation experiments. By comparing the responding curves of critical parameters before and after the control is applied, the result showed that the severe consequence could be avoided after applying the control strategy and the stable operation was realized.
Effect of Structure-Soil-Structure Interaction on the Seismic Response of the Nuclear Building of Small Modular Reactor
Authors: Wang Dongyang , Sun Xiaoying , Zhang Chaoqi
Published: November 2024

The seismic Category I structures within the nuclear island of the Small Modular Reactor (SMR) are densely clustered and connected through the underlying foundation soil. This study discusses the phenomenon of structure-soil-structure interaction (SSSI), where the soil medium transmits seismic responses from one structure to its adjacent structures, employing the sub-structuring method. Seismic response analyses are conducted for the nuclear island structures of SMR, with and without considering the SSSI effect. The impact of SSSI on the seismic responses of the nuclear buildings is investigated by comparing their in-structure response spectra (ISRS). The results indicate that SSSI has a minimal influence on the dynamic response for structures with large volumes, as no significant changes are observed in the acceleration response spectra shape, dominant frequency position, peak acceleration, and zero period acceleration value of the ISRS. However, an evident impact is observed on the dynamic response for the standby diesel generator building due to the SSSI effect. Although the response spectra shape remains virtually unchanged, a slight decrease in main frequency is detected after considering the SSSI effect, along with variations in the spectral peak acceleration value and zero period acceleration value to a certain extent.
Vigorously Develop Nuclear Power to Meet the Challenge of the Rapid Growth of Electricity Consumption and Carbon Emission in the Information Industry
Authors: Li Yingnan , Wu Fang , Tang Te , Liu Weili
Published: November 2024

The information industry is developing rapidly, but the rapid growth of the electricity demand in information industry has not been paid enough attention. According to our research of this paper, the electricity demand in information industry will exceed 10,000 TWh (10 trillion kilowatt-hour) in 2030. As a result, on the one hand, the speed increase of global installed capacity should be 60% higher than the current forecast, in order to meet the electricity demand of information industry. Additionally, due to the acceleration of carbon emission across the information industry, it will be more difficult to achieve the goal of 1.5°C temperature rise limit by 2030. On the other hand, in the historical process of green adjustment and low-carbon transition of the global energy structure, the electricity cost in the information industry will also increase significantly. Namely, with the rapid development of the information industry, the information industry itself, global power supply, carbon emission and electricity price balance are facing more severe challenges. According to the study in this paper, it is believed that vigorously developing nuclear power is the most economical and realistic way to effectively deal with these challenges.
Experimental Study of Bubble Migration Characteristics in MCCI Molten Pool
Authors: Yang Guorui , Zhang Jing , Wu Yingwei , He Yanan , Qiu Suizheng , Su Guanghui , Tian Wenxi
Published: November 2024

When the molten core-concrete interaction (MCCI) occurs in a reactor, the high-temperature melt may melt through the concrete bottom plate and form a molten pool. At the same time, due to the heat generated by decay heat and chemical reactions, the concrete will decompose and produce a large amount of water vapor and carbon dioxide and other gases. After entering the molten pool, these gases will migrate within it and have a stirring effect on the molten pool. This study focuses on the phenomenon of gas migration in MCCI molten pool, and establishes an experimental platform for studying the migration characteristics of gas in MCCI. A 25% glycerol aqueous solution was used as a substitute fluid for the melt, and helium gas was used as a substitute gas to study the migration characteristics of gas in the molten pool. The experimental platform has 49 ventilation holes, which can simulate the migration of bubble groups in the molten pool, and each ventilation hole can adjust the apparent gas velocity separately. The experiment mainly measured the migration velocity, equivalent diameter, and aspect ratio of bubbles. By adjusting the gas flow rate, the changes in these three parameters were studied to obtain the migration characteristics of bubbles. Through this study, it was found that with the increase of apparent gas velocity, the equivalent diameter of bubbles increases, the aspect ratio of bubbles decreases, and the final stable velocity of bubble migration increases. Through this study, the variation patterns of bubble size, shape, and velocity under different gas flow rates were obtained, which can provide support for systematic calculation programs to calculate chemical reactions, fission product release, and molten pool stratification in MCCI processes.
Research and First Application of 4D Radiation Dose Calculation in China
Authors: Liu Zhaoxing , Zhao Ri , Liang Runcheng , Zhang Jing , Liu Xin , Liu Liye
Published: November 2024

Current techniques for calculating radiation doses can only provide 3D static dose distributions for upright individuals, falling short of meeting the demands for precise protection in the future. In pursuit of achieving 4D dose calculations, this study implemented polygonal-surface computational human phantoms deformations using three algorithms based on rigid body rotation matrix, volume Laplacian operators, and As-Rigid-As-Possible (ARAP) method. Subsequently, the research on motion-capture-guided phantom deformation was done. Utilizing the tetrahedral transformation technique based on the Delaunay algorithm, high-speed Monte Carlo calculation was achieved. The established methodology underwent first application in nuclear power plants, and the application results, specific to radiation work processes, validated the reliability and practicality of the proposed method. This breakthrough in key technological aspects of the 4D dose calculation method demonstrates its potential application in personnel precision protection during the operation and maintenance of nuclear facilities. The developed technology holds promise for advancing radiation protection in various scenarios within the nuclear industry.
PERFORM: High Temperature and Pressure CHF Experiment Bench Under Six Degrees of Freedom Motion Condition
Authors: Xia Binzhuo , Xia Fanting , Yang Yiming , Zhang Kui , Chen Ronghua , Tian Wenxi , Qiu Suizheng
Published: November 2024

The critical heat flux is the heat flux when the heat transfer on the surface of the nuclear fuel element deteriorates. Once CHF occurs, the fuel element temperature will rise sharply, resulting in a serious nuclear accident. Motion conditions impact the nuclear reactor in a number of ways, including the micro-level CHF mechanism as well as the flow and heat transfer characteristics and bubble distribution in the core. As a result, conducting the CHF test under motion conditions is required. In this study, a high temperature and pressure CHF experiment bench under six degrees of freedom motion condition named PERFORM was designed and built. The test bench was then used for benchmark tests, parameter control during the test was tested and analyzed, and the CHF test results were compared and analyzed with LOOK-UP-TABLE. The findings demonstrate that there is typically less than a 10% difference between the test data of the benchmark test and the LOOK-UP-TABLE approach, indicating the reliability of the PERFORM bench and the accuracy of the CHF test results that are derived from it.
A Study of Vortex Shedding Acts on Steel Vent Stack Based on EU Standards
Authors: Yuanda Liu , Xiting Wu , Minghao Tang
Published: November 2024

This paper calculates and analysis the crosswind resonance and load acts on the steel vent stack of a UK nuclear power plant which caused by the vortex shedding. It is based on BS EN standards. Both downwind loads and cross wind load which perpendicular to the wind velocity are generated when the wind acts on the structure with a circular section. That may cause a huge displacement or damage of the structure. So some measure to reduce the impact is necessary. This paper discuss impaction on self supports stack which cause by structure free length and the supports form and the fatigue. And compares the difference between the Chinese codes and EU codes.

The cross wind load is caused by the vortex shedding effect. When the wind load acts on the structure, it will produce alternating vortices behind both sides of the chimney, and alternately fall off from one side to the other side, forming the vortex shedding effect. When a vortex is created on one side of the structure, the wind speed on the other side increases, causing the air pressure to drop. As a result, the structure is subjected to lateral forces on one side of the vortex. When the vortex alternates on both sides of the structure, a harmonic lateral load with the same frequency as the vortex is formed. Therefore, the fatigue effect caused by fluctuating wind load should be considered in the design of the structure.

As a tall structure, the steel stack must control and reduce wind vibration, especially cross wind vibration, to achieve safety and economic indicators.

If a horizontal support is anchored on middle of the stack, it can not only share the horizontal load at the bottom of the structure, but also reduce the calculation length of the result and increase the natural vibration period of the structure. It can be seen from the calculation in this paper that the structure without horizontal support needs to increase its damping to avoid dam4age by adding frequency modulated mass dampers or wind rings. The cross-wind load caused by vortex shedding is mainly related to the natural vibration frequency of the structure and the logarithmic damping of the structure in BS EN standards. Therefore, the cross-wind effect can be reduced by increasing the logarithmic damping of the structure, optimizing the structure design, and changing the natural vibration frequency of the structure.
Differential Method for Predicting Heat Transfer Deterioration Regimes in Supercritical Channels and Rod Assemblies
Authors: Filonov Vladislav , Filonova Yuliia , Kovalenko Oleksandr , Fedorov Dmitriy
Published: November 2024

The paper considers a method for determining the heat transfer and hydraulic resistance coefficients at supercritical parameters based on the “narrow channel” approximation. This approach takes into account the presence of transverse exchange of momentum and energy, the intensity of which depends on the radial profile of shear stresses and, to a first approximation, considers density pulsations in the gravity field. In contrast to the classical CFD approach of the same spatial dimension, the described method is simpler, although it remains unclosed with respect to the longitudinal pressure gradient. To overcome this issue, a one-dimensional approach based on the transfer matrix method is used. The technique incorporates an integral form to determine the local HTC (Lyon integral) and friction. The paper provides validation of the approach based on probe experimental studies for CO2, where not only axial temperature profiles during upward and downward flow were experimentally obtained, but also radial profiles were studied in the section with maximum temperature under heat transfer deterioration (HTD). Good agreement in the temperature profiles in the axial and radial directions was obtained in calculations. The considered method predicts the presence of “laminarization” under HTD. An attempt was made to adapt the method for calculations of assemblies in the channel approximation. The results were compared with the studies on the assemblies of fuel rod imitators with supercritical water. The proposed modification of the “narrow channel” method can be used as an alternative to correlations in system codes to perform improved estimations.
Experiment Study on the Liquid Film Behaviors of Annular Flow in the Rectangular Channel
Authors: Ren Quan-yao , Pu Zeng-ping , He Qingche , Liu Haidong , He Hui , Xiao Zhong , Pan Liang-ming
Published: November 2024

Critical heat flux (CHF) is the most important parameter related to the safety performance of heat exchanging equipment, whose triggering mechanisms are very complex and complicated. The prediction of dry-out critical heat flux in a narrow rectangular flow channel was usually based on the accurate prediction on the instantaneous liquid film spatial distribution and its characteristics in annular flow, such as liquid film thickness and disturbance wave destruction rate, and other key parameters. Therefore, it is essential to conduct detailed research on the liquid film behaviors for the annular flow in the narrow rectangular channel. In order to obtain the liquid film thickness, the plate-type liquid film sensor was developed by utilizing the huge differences of electrical conductivity between gas and liquid. The corresponding relationship between the measured voltage and the real void fraction was established with calibration of empirical model, and then the void fraction was converted into liquid film thickness theoretically. Based on the plate-type liquid film sensor, the liquid film was measured in the narrow rectangular channel with a cross-section of 4 mm × 66 mm at different flow conditions. The effects of liquid flow velocity and gas flow velocity on the averaged liquid film thickness and dynamic fluctuation characteristics were analyzed. This study provided data support and theoretical guidance for the accurate prediction of the dry-out type critical heat flux, and was helpful for the design of the fuel assemblies consisting of narrow rectangular channel and the safety assessment of nuclear reactor systems.
Numerical Investigation of Natural Convection Heat Transfer Characteristics in a Swinging Cavity
Authors: Xing Lize , Liu Xiongbin
Published: November 2024

Floating nuclear reactors offer significant advantages in fields of remote island power supply. However, previous studies have mainly focused on the one-dimensional pipeline systems, and there is limited research on the natural convection characteristics within 2- or 3-dimensional enclosed spaces. This study employs a numerical method to investigate the effect of ocean motion on the natural convection characteristics of a square cavity. The cavity has an isothermal heated wall surface at 333K and an isothermal cooling surface at 313K, and the range of the swing period was chosen as [16s, 96s]. The numerical results indicated that while centripetal and Coriolis forces had little effect on heat transfer performance, they did improve the system’s ability to resist interference, with the most significant contributions to natural convection coming from thermal buoyancy and tangential force. Furthermore, as the swing period increased, the relative intensity of thermal buoyancy and tangential force changed, resulting in two distinct heat transfer performances. When the intensity of tangential force greatly exceeds or falls short of thermal buoyancy, the heat transfer curve remains constant for the majority of the period. Conversely, when the intensities were comparable, the heat transfer curve became sharp and unsteady. The findings of this investigation could provide a useful basis for subsequent research on marine nuclear energy systems and equipment.
Scaling of Horizontal Steam Generator Based on Three-Dimensional Thermal-Hydraulic Simulations
Authors: Lazarevic Milos , Stevanovic Vladimir , Petrovic Milan M. , Milivojevic Sanja , Ilic Milica
Published: November 2024

Thermal-hydraulics of horizontal steam generator (HSG) is numerically simulated and analyzed for the full-scale real HSG at the nominal 100% power built in the 1000 MWe nuclear power plant with the pressurized water reactor and for the scaled-down HSG design with all characteristic dimensions reduced to 50% of the full dimensions and operating at 12.5%, 15.7% and 18.7% of the 100% power of the real HSG. The scaled-down HSG designed is considered with the aim to investigate a design that suits the needs of a nuclear power plant with small modular reactor (SMR), which components should be manufactured in a factory and transported to and assembled at the power plant location. The several power levels of the scaled HSG are applied in the performed simulations in order to obtain steam void and water and steam velocities fields that should provide operating parameter values close to the proven safe and reliable values of the 100% full-scale HSG with mature operating experience. The simulations are performed with an in-house code based on the three-dimensional two-fluid model of two-phase flow and appropriate closure laws for the prediction of interface transport processes, such as vapour-liquid interface friction, vapour and liquid wall friction and liquid evaporation rate under thermal non-equilibrium conditions. The obtained results show a difference between geometry and power scaling. The 50% geometry reduction leads to about 80% of HSG power reduction.
Optimal Design of a Coupling System of Heat Pipe Cooled Reactor With Battery Energy Storage System
Authors: Liu Limin , Liu Ziyin , Guo Ziang , Gu Hanyang
Published: November 2024

Micro nuclear reactors have been seen as one of the potential nuclear energy solutions to carbon emission reduction due to their compact design, flexibility, and economic merits. Heat-pipe-cooled nuclear reactors (HPR) can achieve attention due to their avoidance of single-point failure, passive core heat removal capability, and modularity. If applied in remote grid communities or mining operations, the HPRs will face the challenges of high variability in energy demand and relatively long response time in reactors. This paper presents a conceptual design for a hybrid energy system that combines HPRs with a battery-based energy storage system. The system models are set for the reactor-based hybrid system, which includes the core, heat pipe, Brayton energy conversion system, and battery system. Evaluation is performed on the HPR-based hybrid system to examine its responsiveness to time-varying energy demands. The result shows that the HPR-battery hybrid energy system can significantly increase the load following performance and avoid the abrupt power change appearing in the HPR.
Research on Peaking System of Nuclear Power Plant Based on Energy Storage Scheme of Hydrogen Production and Ammonia Synthesis
Authors: Shi Lingyue , Ye Cheng , He Qinglun , Huang Hong
Published: November 2024

With the continuous advancement of the “dual carbon” strategic goal, the power industry, as the main force of energy consumption, actively carries out technological innovation and improves the utilization ratio of clean energy, so the demand for nuclear power peak shaving gradually increases. Based on the current situation of electric power energy utilization and hot research on the green development path of hydrogen production and ammonia synthesis, this paper puts forward a peaking solution of a new energy storage system for nuclear power plants based on green electricity conversion. Taking the daily load tracking mode of AP1000 nuclear power unit as an example, considering the operation efficiency under different loads, the power regulation process of the system is quantitatively calculated by using APROS simulation software. We add a waste heat recovery and utilization structure to improve the energy utilization efficiency, and the economy of this system is evaluated to be more persuasive. It provides an idea of transforming surplus electricity into zero-carbon energy storage for peak shaving problem of nuclear power plants, and has certain reference significance for the development of nuclear comprehensive utilization.
Kriging Surrogate Modelling of Multiplication Factor With Random Effect
Authors: Wang Yizhen , Hao Chen
Published: November 2024

Large computational expenses hinder the use of Monte Carlo simulations in reactor design optimization. Surrogate modelling could therefore be used to reduce such computational expense by constructing computationally inexhaustive models for certain reactor responses of interests. However, the random effect inherited in Monte Carlo neutronics simulation results are generally not considered during constructing such surrogates, which is expected to result in large surrogate prediction biases. In this work, a stochastic Kriging surrogate modelling technique is used to reproduce Monte Carlo estimated multiplication factor while explicitly taking their random effects into account. It is shown that involving random effect in Kriging surrogate modelling process could significantly improve the accuracy of surrogate predicted multiplication factors. Specifically, it could mitigate the fluctuation appeared in Kriging surrogate predicting biases, and narrow the surrogate predictions centered around the mean values of referenced Monte Carlo simulated multiplication factor. It is analyzed that stochastic random effect resulted non-smoothing variation of multiplication factor with varying design inputs is responsible for such observation. As Kriging method follows Gaussian process assumption, where the commonly adopted Radial Basis Kernel (RBK) is not able to model the non-smoothing distance related correlation appeared in responses with random effect. Including an additional extrinsic covariance in the Kriging modelling process could therefore mitigate such non-smoothing behavior and stabilize surrogate model’s prediction performance.
Dynamic Simulation of a Small Modular Sodium-Cooled Fast Reactor Coupled With Molten Salt Energy Storage System
Authors: Jin Jinrong , Wan Jiashuang , Wu Shifa , Nuerlan Areai
Published: November 2024

The small modular sodium-cooled fast reactor plays a vital role in Generation-IV reactors, requiring the capability of load-follow operation to address the challenges posed by rapidly fluctuating electric loads on the power grid. Nevertheless, the thermal and mechanical stresses associated with load-follow operation can be undesirable for fuel and other reactor components. To address this, an alternative approach is proposed, focusing on operating the reactor at or near steady state and storing excess energy in a thermal heat storage system. The stored thermal energy can be efficiently utilized during periods of peak electric demand, effectively mitigating grid variability resulting from daily load demand changes and intermittent renewable energy sources. The sodium-cooled fast reactor is the most promising candidate for coupling with the molten salt thermal heat storage systems because the reactor coolant inlet and outlet temperatures of sodium-cooled fast reactors are in the margin of the molten salt working temperature. This study focuses on the integration of a molten salt energy storage system between the intermediate sodium loop and secondary loop of the modular sodium-cooled fast reactor. By employing this configuration, the coupled system enables the reactor to operate at nominal full power effectively, even during periods of variable electric demand. The research emphasizes the dynamic responses and control strategy of the coupled system. Initially, mathematical models for the small modular sodium-cooled fast reactor and molten salt energy storage system are proposed and implemented using MATLAB/SIMULINK. Subsequently, according to the operation strategies and control logics, the conventional PID control systems are designed for both the small modular sodium-cooled fast reactor and molten salt energy storage system. The dynamic simulations of load-follow scenarios are conducted to assess the performance of the small modular sodium-cooled fast reactor coupled with molten salt energy storage system. The simulation results demonstrate the feasibility of utilizing a molten salt energy storage system coupled with a small modular sodium-cooled fast reactor to efficiently minimize power swings during periods of variable electric load. Consequently, the coupled system significantly enhances the operational flexibility, safety, and cost-effectiveness of the sodium-cooled fast reactor, making it a promising and sustainable solution for ensuring grid stability and meeting the increasing energy demands of the future. Overall, this research contributes to advancing the state-of-the-art in small modular reactor technology, providing valuable insights into the integration of energy storage systems with sodium-cooled fast reactors, and showcasing the potential benefits in terms of enhanced operational performance, grid stability, and sustainability.
Evaluating the Impact of Neutron Absorber Materials on Spent Fuel Pool Rack Criticality Using OpenMC Monte Carlo Code
Authors: Buyrukcu Busra , Buyrukcu Eray , Litskevich Dzianis , Whittle Karl
Published: November 2024

The impact of different neutron absorber materials on the criticality of the spent fuel pool rack geometry has been investigated in this study. OpenMC Monte Carlo code has been used for modelling the geometry of the spent fuel pool rack and the k-eigenvalue/criticality calculations. The criticality calculations consist of three stages. In the first stage, the k-eigenvalue criticality calculations were made using two different neutron absorber plates, which are an aluminium-boron carbide composite and a Gd-containing aluminium-boron carbide composite. In the following stage, k-eigenvalue calculations were performed by removing neutron absorber plates from the rack geometry and adding Gd (1 wt.%) directly to the rack wall composition. In the final stage, criticality calculations were made by using different neutron absorber elements like Gd, B, and Sm and their different concentrations within the rack wall composite. It can be understood from the analyses that Gd is a significant neutron absorber material, particularly when it is incorporated directly within the spent fuel pool rack wall composition. With this approach, the need for neutron absorber plates has been eliminated by adding neutron absorber elements directly within the rack wall composition. In this way, systems will become simpler, and potentially, the cost will be reduced.
Dynamic global model of Cl2/Ar plasmas: Applicability to atomic layer etching processes
Authors: Rasoanarivo T. , Mannequin C. , Roqueta F. , Boufnichel M. , Rhallabi A.
Published: November 2024

A global zero-dimensional (0D) model has been developed to describe the Cl2/Ar plasma discharge in dynamic mode. Our model computes the time evolution of the plasma composition under conditions similar to fast-paced plasma processes, such as atomic layer etching (ALE), characterized by alternations in the feed gas. The study focuses on calculating the densities of charged and neutral species for various gas switch durations, (ts). Simulations demonstrate the impact of gas switching time (ts) on the temporal evolution of Cl2, Cl, and ion densities, as well as the electron temperature (Te) during the gas switch. A parametric study reveals that the temporal evolution of Te can be represented by a semiempirical exponential law during the transition from a pure Cl2 plasma to Ar as a function of (ts). During the gas switch, the extinction of chlorinated species, which plays a crucial role in the adsorption step in ALE, persist during the argon plasma phase. The duration of this extinction decreases with longer ts. Finally, our model shows a good reproducibility of ALE cycles modeled for the chosen input parameters, including the densities of neutral and charged species and Te, relative to the ALE period. This work aims to provide insights into the kinetics of transient plasmas occurring in the ALE cycle, the importance of purging, and lifetime residual species, such as residual chlorine in a plasma with pure argon.
Preliminary Insight on Cognitive Training for Improved Outcomes in Elite Female Esports Athletes
Authors: Zakalski Natália , Hart Jesse
Published: November 2024

Objective: To identify cognitive performance markers for esports athletes and evaluate the impact of targeted noncomputerized cognitive training on professional female players. Methods: Study 1 compared cognitive performance of male (n = 26), female subject team (n = 5), and other female (n = 12) professional first-person shooter players to identify cognitive areas of interest. Study 2 involved a 5-month light board cognitive training intervention with the subject team. Cognitive performance was assessed pre- and postintervention using nonparametric hypothesis tests. Results: Study 1 revealed performance differences primarily in action reprogramming tasks. In Study 2, significant improvements were observed in overall action reprogramming task performance, particularly in “no switch” (p = .010) and “cue switch” (p = .004) trials. Conclusion: Action reprogramming tasks may be of interest as a cognitive marker for first-person shooter player development. Targeted noncomputerized cognitive training may enhance these specific cognitive abilities in female athletes, potentially helping to close performance gaps. Implications: While promising, these results necessitate further investigation with larger sample sizes to verify effects and explore their sustainability. This study provides a foundation for developing tailored training strategies to promote gender equity in esports.
Gated off-site radical injection: Bidirectional conductance modulation in single-molecule junctions
Authors: Zhang Hanjun , Chen Lichuan , Liu Xiaodong , Sun Fanxi , Zhang Maolin , Quintero Sergio Moles , Zhan Qian , Jiang Shenqing , Li Jiayu , Wang Dongsheng , Casado Juan , Hong Wenjing , Zheng Yonghao
Published: November 2024

Uncovering the effects of radical injection into responsive organic molecules is a long-sought goal, and the single-molecule junctions provide a unique way to investigate molecular conductance evolution during the radical injection. We can modulate the main channel conductance by using electronic injection from off-site neutral radicals acting as gating terminals. Two families of cyclopentadienone derivatives were synthesized, featuring the inter-pyridyl main conductance channel and the inter-radical paths that are linear (FCF) or cross conjugated (PCP). Using a scanning tunneling microscope break junction technique, we find that the injection of mono- and diradicals in the PCP system unexpectedly decreases the conductance regarding the closed-shell analog, while that of FCF systems increases. Through-bond and through-space conductance mechanisms are found in the FCF and PCP series, respectively, and jointly modulate the overall charge transmission. This off-site injection concept offers a promising approach for developing molecular devices by manipulating electrical conductance in single-molecule junctions.