bluuebunny/crossref_metadata_2025 huggingface dataset:
T. Muris Infection Dynamics of a Fresh, Wild Isolate: Is the Established E Isolate Still Relevant?
Authors: Mair Iris , Bennett Alexander R. , Forman Ruth , Othman Abdulrazzag A. , Logunova Larisa , Smith Hannah , Lowe Ann E. , Bradley Janette E. , Thornton David J. , Else Kathryn J.
Published: October 2024

For decades, parasitic worms such as Trichuris muris have been maintained in laboratory animals, providing insights into host–parasite interactions and host immune responses. The most used T. muris isolate is the E isolate, established in the laboratory in 1954. However, one concern with these model systems is the potential for laboratory‐induced selection and therefore changes in host–parasite interactions. To address these concerns, we compare the E isolate with a recently isolated T. muris isolate (M isolate), established from wild house mice (Mus musculus domesticus, Isle of May, UK), in their capacity to infect laboratory mice. High dose infection of C57BL/6 mice revealed that significantly more parasites of the M isolate survived to the adult stage compared to the E isolate. Worm persistence was associated with heightened TNF‐α and IL‐10 secretion upon parasite‐specific re‐stimulation, and higher serum IgG1 and IgG2c levels, concomitant with an increase in T‐bet+ and ICOS+ CD4+ T effector‐memory cells. Differences in host response to the isolates were not as pronounced during low dose infection. Our study highlights the need for regular evaluation of lab‐maintained parasite isolates against freshly isolated parasites to understand whether the established lab strains remain relevant model systems for our understanding of parasitic infections.
The concealed information test with a continuously moving stimulus
Authors: Wolsink Lianne N. , Meijer Ewout H. , Smulders Fren T. Y. , Orthey Robin
Published: November 2024

The Concealed Information Test (CIT) aims to extract concealed crime‐related knowledge using physiological measures. In the present study, we propose a new variant of the CIT that contains a continuously moving stimulus. A total of 81 participants were either informed or not about the specific location of an upcoming terrorist attack. The CIT consisted of a map with a superimposed moving dot, combined with measurements of respiration and electrodermal activity. The results revealed both respiratory suppression and an increase in skin conductance when the moving dot passed the target location only in informed participants. These findings showed that this new variant of the CIT can differentiate between groups of informed and uninformed individuals and an exploratory analysis revealed it can help narrow down a search area.
Supplementing the Beltsville Extender With Mitoquinol Improves the Quality and Fertility Potential of the Rooster's Cooled Sperm
Authors: Nateghi Reihaneh , Masoudi Reza , Asadzadeh Nader
Published: November 2024

Supplementing freeze diluents with certain antioxidants can maintain the quality of chilled sperm. The present study was an attempt to investigate the effect of Beltsville extender supplementation with the mitochondrial‐targeted antioxidant ‘Mitoquinol’ on the quality parameters and fertility potential of rooster sperm during the cooling process. Semen samples were diluted in Beltsville extender, divided into five groups, and supplemented with 0, 1, 10, 100 and 1000 nM Mitoquinol. Samples were stored at 5°C for up to 50 h and then assayed for sperm motility, viability, mitochondrial function, membrane integrity and malondialdehyde concentration after 0, 25 and 50 h of cooling. To assess reproductive performance, artificial insemination was performed using sperm cooled for 25 h. The results showed no differences between groups at the beginning time. Extender supplementation with 10 and 100 nM Mitoquinol resulted in an improvement in total motility, progressive motility, membrane integrity, mitochondrial function and viability (p ≤ 0.05), as well as a lower malondialdehyde concentration (p ≤ 0.05) in comparison to the other groups during 25 and 50 h storage. Fertility rates were higher when roosters were inseminated with semen samples supplemented with 10 and 100 nM Mitoquinol, compared to the control group. Therefore, supplementing Beltsville extender with Mitoquinol (10 and 100 nM) effective in improving the quality and fertility potential of cooled rooster sperm.
Fast and simple fluorometric measurement of phloem loading exposes auxin‐dependent regulation of Arabidopsis sucrose transporter AtSUC2
Authors: Ren Yunjuan , Zhang Ziyu , Zhanakhmetova Diana , Li Wenhui , Chen Shaolin , Werner Tomáš , Liesche Johannes
Published: November 2024

The rate of sucrose export from leaves is a major factor in balancing whole‐plant carbon and energy partitioning. A comprehensive study of its dynamics and relationship to photosynthesis, sink demand, and other relevant processes is hampered by the shortcomings of current methods for measuring sucrose phloem loading. We utilize the ability of sucrose transporter proteins, known as SUCs or SUTs, to specifically transport the fluorescent molecule esculin in a novel assay to measure phloem loading rates. Esculin was administered to source leaves and its fluorescence in the leaf extract was measured after 1 or 2 h. Dicot plants with an active phloem loading strategy showed an export‐dependent reduction of esculin fluorescence. Relative leaf esculin export rates correlated with leaf export rates of isotopic carbon and phloem exudate sucrose levels. We used esculin experiments to examine the effects of phytohormones on phloem loading in Arabidopsis, showing, for example, that auxin induces phloem loading while cytokinin reduces it. Transcriptional regulation of AtSUC2 by AUXIN RESPONSE FACTOR1 (ARF1) corroborated the link between auxin signaling and phloem loading. Unlike established methods, the esculin assay is rapid and does not require specialized equipment. Potential applications and limitations of the esculin assay are discussed.
Estimated Plasmodium18S ribosomal RNA prevalence in asymptomatic blood donors from three African countries
Authors: Tonnetti Laura , Groves Jamel A. , Self Deanna , Yadav Manisha C. , Tayou Tagny Claude , Rakoto Alson Olivat A. , Livezey Kristin , Linnen Jeffery M. , Stramer Susan L.
Published: October 2024

Background and Objectives

The World Health Organization (WHO) African Region accounts for 94% of malaria cases globally, with variability recognized within endemic regions. To determine the detection rate of Plasmodium RNA in blood donors resident in malaria‐endemic areas, samples from three African countries were tested using a Plasmodium nucleic acid test.

Materials and Methods

Whole blood (WB) samples collected from routine donors in Cameroon, Madagascar and Mali were shipped frozen to the United States. Samples were tested individually from WB lysates with the Procleix Plasmodium assay (transcription‐mediated amplification [TMA]). Reactive samples were considered either repeat reactive or initial reactive only, depending on TMA‐retest results. When available, matching plasma samples were tested for Plasmodium antibodies by enzyme immunoassay (EIA).

Results

Plasmodium repeat reactivity ranged from 41% (91/223 tested) in Cameroon to 12% (26/216) in Mali and 1% (3/249) in Madagascar. Initially reactive samples, where reactivity did not repeat, were identified from Cameroon (5/223; 2%) and Mali (2/216; 1%). The matched‐plasma subgroup had EIA reactivity ranging from 86% (113/131 tested) in Cameroon to 59% (10/17) in Mali and 27% (68/248) in Madagascar.

Conclusion

Plasmodium ribosomal RNA (rRNA) detection and antibody rates varied greatly in the three countries studied. Detection of Plasmodium rRNA can provide an additional tool to address malaria risk in blood donors.
Bi-Level Interturn Short-Circuit Fault Monitoring for Wind Turbine Generators With Benchmark Dataset Development
Authors: Yan Jingyi , Senemmar Soroush , Zhang Jie
Published: November 2024

Flourished wind energy market pushes the latest wind turbines (WTs) to further and harsher inland and offshore environment. Increased operation and maintenance cost calls for more reliable and cost effective condition monitoring systems. In this article, a bi-level condition monitoring framework for interturn short-circuit faults (ITSCFs) in WT generators is proposed. A benchmark dataset, consisting of 75 ITSCF scenarios and generator current signals of a specific WT, has been created and made publicly available on Zenodo. The data are simulated at a rate of 4 kHz. Based on the time and frequency features extracted from data processing, machine learning-based severity estimation and faulty phase identification modules can provide valuable diagnostic information for wind farm operators. Specifically, the performance of long short-term memory (LSTM) networks, gated recurrent unit (GRU) networks, and convolutional neural networks (CNNs) are analyzed and compared for severity estimation and faulty phase identification. For test-bed experimental reference, various numbers of scenarios for training the models are analyzed. Numerical experiments demonstrate the computational efficiency and robust denoising capability of the CNN algorithm. The GRU network, however, achieves the highest accuracy. The overall system performance improves significantly, from 87.76% with 16 training scenarios to 99.95% with 52 training scenarios, when tested on a set containing all 76 scenarios from an unforeseen period.
Analytical Modeling of Bistable Beam With Double-Ring-Shaped Deformation Element
Authors: Patel Sandip T. , Dave Harshit K.
Published: November 2024

The field of negative stiffness structures has recently seen an increase in attention as a result of advancements in additive manufacturing (AM) technology. These advancements have made it possible to produce materials in a more expedient manner. The purpose of this research is to demonstrate a highly tunable and reusable bistable beam design that is based on a double-ring-shaped deformation element that undergoes pure bending, unlike traditional bistable mechanisms with buckling-based deformation elements. Further, an analytical model is developed and then validated by means of experimental and numerical results to precisely predict the snap-through behavior of a beam. It has been shown that the analytical model that was proposed has accuracy in terms of foreseeing the snap-through transition. A detailed study is conducted to explore the influence of geometric parameters on the snap-through characteristics. By carefully modifying these geometric properties, the required mechanical behavior of negative stiffness metamaterial (NSM) may be achieved for specific applications.
Study of Gravity Effect on the Operating Characteristics of High-Temperature Bent Heat Pipes
Authors: Zhang Zhipeng , Wang Chenglong , Guo Kailun , Tian Wenxi , Su Guanghui , Qiu Suizheng
Published: November 2024

As a high-efficiency heat transfer element, heat pipe can be well adapted to the application scenarios of high heat flow density and high safety requirements in the field of nuclear engineering. This paper carries out experiments on a high-temperature sodium heat pipe, and obtains its operating characteristics in the straight pipe state and the bending state respectively. And the operating conditions of the condenser section under different gravity effect was compared. The results show that in the startup process, the temperature difference between the entrance and exit of the bent section increases significantly due to the increase of flow resistance in the bent region. At the same time, even in the bending section of the exit has been started under the conditions of the bending of the temperature difference between the entrance and exit after bending still exists, when the heat pipe into the full start-up state, the temperature difference is gradually reduced to about 10 °C. After bending, the evaporation section to the condenser section of the temperature difference increases, the adiabatic section of the entrance and exit of the obvious temperature difference; and the heat pipe performance of the degree of loss is also related to the bending of the condenser section of the gravity of the orientation.
An Empirical Study of Radionuclides Behavioral Characteristics in Oceanic Biota From Waste Water Ejection
Authors: Oforiwaa Priscilla Obeng , Zhang Xiaole , Su Guofeng
Published: November 2024

The concept of ecosystem changes of radionuclides is important to ensure product management for food safety. The Fukushima nuclear accident which happened in recent years released a massive concentration of radiocesium into the ocean and subsequent water bodies across Japan. In this research, our main mandate is to study the behavior of some radionuclides (Cesium (CS) 137, Strontium (Sr) 90, Carbon (C) 14, and Tritium (H3). These radionuclides transfer occurs through aquatic pathways to aquatic animals as confirmed in a simulation and air monitoring surveys. The decay characteristics and the transfer medium in Pisceverous Fish species, Benthic Fish species, and Forage Fish in the Pacific Ocean; understanding the decay mode, and transfer model is the driving force of the development of systematic policy models for a nuclear emergency. The oceanic study concentration in some sea mammals and herbivores was developed using the exponential double dynamic model. The results indicate that Pisceverous fish species such as octopus and squid are predicted to have a higher concentration at the onset of an emergency.

On the Allometric scale a predicted concentration of 0.766mSv of radioisotope concentration in an oyster fish. The southern belt oysters are observed to contain a higher sediment property, thus the susceptibility of concentration in this fish species is higher than its normal level.
Time-Domain Nonlinear Investigation of Two-Phase Flow Instability in HTGR OTSG Using SIMULINK
Authors: Su Yang , Li Xiaowei , Wu Xinxin
Published: November 2024

Two-phase flow instability may occur in the once-through steam generator (OTSG) of High-Temperature Gas-cooled Reactors (HTGR). A time-domain theoretical model of HTGR OTSG was established to investigate this phenomenon. The heat transfer tube of OTSG was divided into three regions, namely the subcooled water region, the saturated two-phase region and the superheated steam region. The influence of inlet resistance coefficient could not be accurately predicted by a single-node model of the saturated two-phase region. Consequently, the saturated two-phase region was subdivided into several regions, each experiencing the same enthalpy increase. The dimensionless one-dimensional partial differential governing equations were transformed into nonlinear ordinary differential equations (NODE) using integration and the Leibniz formula under constant pressure drop boundary conditions. The physical parameters characterizing flow instability were dimensionless inlet flow velocity and the dimensionless length between the entrance and different nodes. These NODE were solved using SIMULINK (a toolbox of MATLAB). The typical characteristic of DWO was captured by NODE and SIMULINK, where the phase of dimensionless inlet and outlet mass flow rates are opposite. The multi-nodes (in the saturated two-phase region) time-domain theoretical model can accurately predict the stability boundary of High-Temperature Gas-cooled Reactor-Pebble bed Module (HTR-PM) OTSG. This multi-nodes model was used to predict stability boundary at start-up conditions further, and there is enough safety margin for HTR-PM OTSG.
Effects on a Bending Pipe Behaviour via Simple Pre-Loading for Considering Functional Limitations of Piping in Industrial Facilities
Authors: Sugiura Ayumu , Takito Kiyotaka , Furuya Osamu , Nakamura Izumi , Okuda Yukihiko
Published: November 2024

This paper investigates the effect of initial plastic deformation on the load-displacement relationship of elbow piping of different wall thicknesses made of elastoplastic material The same conditions are applied in the finite element analysis (FEA). Load tests results and FEA of elbow piping made of carbon steel were conducted when three cycles of sinusoidal input with frequency of 0.02 Hz were applied to one end of the piping. Analyses were performed for three types of piping with different wall thicknesses before and after plastic deformation. The effect of initial displacement on the load-displacement relationship was confirmed by loading test, and analytical investigations were also summarized. Then, Comparison of the test and analytical results confirmed that the basic load-displacement relationship could be expressed qualitatively, such as a decrease in yield load due to a decrease in primary stiffness caused by the amount of initial plastic deformation, but from a quantitative standpoint, errors were observed in the loads. The error rate of the maximum load when the specimen was pulled in the in-plane bending direction tended to decrease as the wall thickness increased, but the error rate of the compression of the specimen in the in-plane bending direction showed a completely different trend from that of the pulling.
Criticality and Burnup Analysis of NuScale Reactors With Various Burnable Absorber Designs and Fuel Isotopes
Authors: Luo Yu-Chen , Wu Shin-Rong , Hong Jhao-Yang , Chao Der-Sheng , Liang Jenq-Horng
Published: November 2024

Burnable absorber (BA) crucial components of specific fuel rods, playing a vital role in managing excess reactivity throughout the entire cycle. This substance not only reduces the initial demand for soluble boron at the beginning of the cycle, thus preventing the occurrence of positive moderator temperature coefficient (MTC) during the initial power operation phase, but also mitigates power differences within the assembly. This study models the reactor design of the NuScale small modular reactor according to the original manual and simulates the neutron physics characteristics of the NuScale small modular reactor with different burnable absorbers (BA) and nuclear fuel isotopes. Two designs of burnable absorbers were employed: one involves coating a layer of burnable absorber directly onto the fuel pellets, while the other involves uniformly mixing the burnable absorber into the fuel pellets. Fuel rods containing burnable absorbers were arranged differently. This study using Monte Carlo N-Particle Transport Code (MCNP6.2) [3] computer code with ENDF/B-VII continuous energy library to calculate. Effective multiplication factor (Keff), burnup, and the residual mass of Gd-157 from first cycle to 730 days.
Liquid Lead-Bismuth Oxygen Sensors Performance Study
Authors: Li Hui , Wu Weihao , Zhu Yuqi , Zhu Huiping , Niu Fenglei
Published: November 2024

Liquid Lead-Bismuth Eutectic (LBE) has become the preferred coolant material for Lead Fast Reactors (LFR) due to its outstanding physical and chemical properties. However, the severe corrosion of structural materials by LBE restricts the development of Lead Fast Reactors. Research indicates that maintaining the dissolved oxygen concentration in LBE within the range of 10−6 – 5 × 10−8 wt.% effectively mitigates corrosion on structural materials. In this process, the measurement and control of oxygen concentration are crucial technologies that urgently need implementation. Oxygen sensors, as key devices for measuring internal oxygen concentration in LBE, are essential for dynamically adjusting the circuit’s oxygen concentration. Based on the Nernst principle, oxygen sensors utilize the high oxygen ion conductivity and low electron conductivity of solid electrolytes, assembled into the form of an electrochemical cell for oxygen concentration measurement. Currently developed oxygen sensors are primarily designed for high-temperature environments, and the Pt/air and Bi/Bi2O3 oxygen sensors used exhibit shortcomings in low-temperature testing performance, making it challenging to meet the oxygen concentration measurement requirements below 300°C in LFR’s cold section. Therefore, there is an urgent need to develop wide-temperature-range LBE oxygen sensors suitable for low-temperature operation. To meet low-temperature measurement requirements, we conducted tests on a water-cooled lead-bismuth platform to evaluate the performance of three reference electrode oxygen sensors: Cu/Cu2O, LSM/air, and LSCF/air. The applicable temperature lower limit of the oxygen sensor depends on the performance of the reference electrode. Experimental data indicate that, within the low-temperature range of 250°C to 300°C, Cu/Cu2O, LSCF/air, and LSM/air reference electrodes perform well, meeting the low-temperature measurement requirements of LFR. The Cu/Cu2O reference electrode exhibits good accuracy within the experimental temperature range after adding correction values. LSM/air and LSCF/air reference electrodes maintain good accuracy across the entire testing temperature range. Compared to metal/metal oxide reference electrodes, air-type reference electrode systems generally exhibit better accuracy. However, all three types of reference electrodes demonstrate excellent stability within the experimental temperature range.
Evaluation of Coolant Mixing Characteristics in the Lower Plenum of a Scaled PWR With OpenFOAM
Authors: Djebara Lilia , Wei Hongyang , Yang Cheng , Tan Sichao , Tian Ruifeng
Published: November 2024

In the realm of nuclear reactor design, ensuring uniform flow rates at the core inlet of Pressurized Water Reactors (PWR) is vital for safety, impacting cooling functions and “fuel hot spot” criteria. This intricate balance is influenced by fluid dynamics in the reactor pressure vessel’s lower plenum, essential for both hydraulic and structural plant design.

The geometric configuration of the lower plenum significantly influences the hydraulic characteristics of the Pressurized Water Reactor (PWR). The flow behavior at lower plenum and downcomer (closer to reactor core) has influences on the distribution of the flow entering the reactor core.

To reach a comprehensive understanding of the thermal hydraulic phenomena in the downcomer and plenum of a scaled PWR reactor pressure vessel, numerical investigations was pursued, employing 3D computational fluid dynamics (CFD) simulations, with a thorough comparative analysis against experimental data obtained through Particle Image Velocimetry (PIV), this PIV analysis allow the visualization and understanding of flow mixing characteristics providing valuable insights into the suspended particles’ behavior.

The geometric model with a 3-loop configuration was meticulously developed, and subsequent meshing and simulations were executed employing OpenFOAM. The selected test case emulated a scaled Pressurized Water Reactor (PWR) reactor pressure vessel, solving a 3D Navier Stokes equations. The simulation incorporated a transient flow algorithm coupled with a standard k-epsilon turbulence model. Explicit meshing was applied throughout. Due to the computational complexity, the utilization of high-performance computing resources was imperative to ensure expedited and accurate results.

The results offer a clear representation of flow patterns within the lower plenum of a PWR, significantly augmenting considerations related to nuclear safety. The computational capability of CFD facilitates the evaluation of various flow distribution device concepts, providing engineers with advanced tools for nuanced insights into their advantages and disadvantages in reactor design.
An Effect of Damage Rate on Mechanical Property Change and Microstructural Evolution in Proton-Irradiated Fe-Cu Alloys
Authors: Noshi Yusuke , Fukumoto Ken-Ichi , Ishigami Ryoya , Uda Kinji
Published: November 2024

Damage rate effects have been recognized as being important for understanding the correlation between mechanical property changes and microstructural evolution in neutron-irradiated commercial reactor pressure vessel steels. In this study, the correlation between the irradiation hardening behavior and defect cluster formation in proton-irradiated Fe-Cu model alloy is investigated using nanoindentation tests and transmission electron microscopy with a variety of damage rates for the proton irradiations. A wide range of damage rates across three orders of magnitude is adopted for the proton flux in a single irradiation experimental system. The hardness in the low damage rate case is higher than in the high damage rate case in the initial stage of damage level when hardening behavior was not saturated. From transmission electron microscopy observations, it is found that a low density of large dislocation loops is formed under lower damage rate conditions. According to the irradiation hardening estimation based on the classical dispersed barrier hardening model, it is indicated that the damage rate effects on the hardening contribution are weak for dislocation loops but dominant for Cu-rich precipitates.
Analysis of Water Hammer in the Reactor Coolant System Based on Wave Tracking Method
Authors: Zhang Qianping , Dong Shubiao , Zhang Xiaoyu
Published: November 2024

To investigate the pressure wave propagation process caused by water hammer in the reactor coolant system, a simulation model of the three-loop main coolant system, consisting of the reactor core, steam generator, main pump, and pressurizer, has been established. The reactor core and steam generator are simplified with equivalent pipes, the pressurizer model is established using a two-phase canister, and the friction torque model of the main pump’s anti-reversal device has been developed. Unlike existing studies, this paper employs the wave tracking method (WTM) for water hammer simulation. Finally, the accuracy of the model is verified by idling experiments after the power failure of the three main pumps (case 1). And the restart of a single main pump after power failure (case 2) and the shaft stuck of the main pump (case 3) are simulated. The results indicate that the simulation results in case 1 are in good agreement with the experimental results, and the pressure wave fluctuates slightly in case 2. In case 3, water hammer occurred in the main pump, the maximum pressure reached 16.66MPa (amplitude 1.47Mpa), and the minimum pressure dropped to 14.97MPa (amplitude −0.94Mpa). The simulation results provide support for the safe operation of the reactor coolant system.
Effect of Nanostructures of Different Sizes on Boiling and Nucleation: A Molecular Dynamics Study
Authors: Gao Deyang , Ma Yue , Bo Hanliang
Published: November 2024

With the development of technology, the energy needs of today’s society are gradually increasing, and methods that can improve heat transfer efficiency within limited volumes are becoming increasingly important. Among various heat transfer methods, boiling is considered an effective way to improve spatial heat transfer efficiency due to its ability to fully utilize phase change latent heat. The design of nanostructures enables further enhancement of boiling heat transfer efficiency, and numerous studies indicate that nanostructures facilitate bubble nucleation and growth during boiling, thereby increasing critical heat flux (CHF). However, existing studies mostly analyze the influence of surface nanostructures on bubbles independently of the heat transfer and potential energy aspects. Possible synergistic or mutually inhibiting effects between the two are hardly taken into account. In addition, boiling heat transfer in a reactor not only improves the efficiency of heat transfer, but can also affect the reactivity and safety of the reactor due to the uneven distribution of bubbles in time and space. Therefore, it is also necessary to consider the influence of nanostructures on the bubble nucleation positions. The entire bubble growth process was directly observed by using molecular dynamics simulations. Furthermore, a detailed discussion was conducted on the influence of nanostructures on nucleation positions, nucleation times, and CHF. The results suggested that not all nanostructures contribute to bubble nucleation; Instead, when the nanostructure size is smaller, bubble nucleation was delayed and CHF is reduced. The mechanism of this phenomenon is revealed by the inhibitory effect between heat transfer and potential energy.
Comparative Analysis of Loss of Coolant Accidents for GEN-III PWRs Based on ACME and ATLAS Facilities
Authors: Huang Yuhang , Zhang Xueyan , Yang Jun
Published: November 2024

ISP-51 and ISP-50 are two recent international cooperation projects organized by OECD/NEA, with the aim of comparing and evaluating the capability of best estimate system codes. ISP-51, led by HUST, is based on ACME (Advanced Core Cooling System Mechanism Experiment) facility scaled from the CAP1400 in China. ISP-50, led by the KAERI, is based on ATLAS (Advanced Thermal-Hydraulic Test Loop for Accident Simulation) facility scaled from the APR1400 in Korea. Both ISPs simulated Loss of Coolant Accident (LOCA) scenarios in the passive thermal-hydraulic facilities and followed the international ISPs practice of conducting blind test and open test. ISP-51 aimed to simulate CAP22 (a small 2-inch break at the cold leg and a failure of one of the four ADS4 valves on the non-PZR side) for the open phase, and CAP16 (a double ended break of direct vessel injection) for the blind phase. ISP-50 aimed to simulate a 50% direct vessel injection line break accident. Both ISPs are based on the LOCA transients on integral test facilities mocked from the representing GEN-III PWRs with similar power level and passive safety features. Since CAP1400 and APR1400 are both of GEN-III PWRs with passive safety features and similar power level, it would be of interest to study these two ISPs, comparatively, by cross-checking and analyzing the prototypic reactors and test facility. This study further enhances the understanding of typical GEN-III PWR technologies, provides us insightful view about the overall design characteristics and passive safety features.
Reducing Variance in Nuclear Monte Carlo Simulations Through Deep Learning Post-Processing Techniques in the Gaming Domain
Authors: Guo Haoxuan , Li Wei , Sang Yaodong , Chen Haizheng , Zhang Qingmin
Published: November 2024

In nuclear science and engineering, Monte Carlo simulation, a critical tool for solving complex physical problems, faces significant computational costs and challenges in achieving high precision due to the extensive time and hardware resources required. Drawing inspiration from the gaming industry, which has developed advanced deep learning techniques for denoising and super-sampling in raster graphics rendering, this study investigates the adaptation and integration of these techniques into Monte Carlo simulations to enhance precision and reduce computational demands. By incorporating deep learning super-sampling and denoising techniques, such as Intel OIDN, NVIDIA OptiX, SRCNN, and waifu2x, as post-processing steps in simulations of nuclear events, the study demonstrates a notable reduction in variance and improvement in accuracy. This novel approach not only presents a promising avenue for improving the efficiency of Monte Carlo simulations in nuclear science and engineering but also opens up possibilities for applying these advanced techniques to a broader range of complex issues in the field.
Ways to Solve the Safe Operation of VVER-1000 Reactors in Case of Loss of Original Rod Cluster Control Assemblies Supply
Authors: Mazurok Oleksandr , Zuyok Valeriy , Ivanov Vadym , Tretyakov Mykhaylo
Published: November 2024

The article briefly presents the results and experience of lifetime extension of operating RCCAs manufactured in RF. It is shown that by reducing conservatism, until the criteria for maintaining the integrity of the fuel cladding are achieved, it is possible to extend the lifetime of almost all RCCAs currently operating at Ukrainian NPPs from 25500 to 38000 hours in the control group and from 75600 to 113500 hours in the shutdown groups. However, the substantiation should be carried out for each RCCA separately, since each one has its own individual history of operation in the reactor core.

The main part of the article is devoted to the ways of increasing the efficiency and extension of RCCA lifetime, and to the development of control rods with improved characteristics. Among the proposed absorbers, the most acceptable neutron absorption efficiency is provided by metallic hafnium with an absorbing part diameter of 8.2 mm (without a cladding) and Dy2O3·HfO2 in the pellet version of filling the lower part of the control rod (up to 300 mm). In the upper part of the rod (from 300mm to 3500mm), Eu2O3·HfO2 composition can be used instead of B4C. Europium hafnate with a density of 8.0 g/cm3 and a tablet filling (6.85 mm) will exhibit an initial neutron absorption efficiency of 95.6% of B4C. The high neutron absorption efficiency will make it possible to use less efficient (n,y) absorbers with extended lifetime (Dy2O3·HfO2, Hf) with a length of more than 300 mm in the lower part without violating the neutron-physical criteria for the performance of the control rod.
Analysis of the Acceleration Effect of Anderson’s Fixed-Point Acceleration Method in Core Neutronics Calculations
Authors: An Ping , Lu Wei , Liu Rui , Li Zhigang , Tang Qifen , Shen Jie
Published: November 2024

Fixed-point iteration is the most widely used iterative format in numerical calculations. The Seidel iterative method is a traditional acceleration method, which is generally used in the source iteration process of core neutronics calculations. During the fixed-point iteration process, the Anderson acceleration method is using the least squares method to find the direction that converges the fastest, based on previous iteration values. The Anderson acceleration method can replace the Seidel iteration directly. So, it can be easily implemented in existing numerical software iteration.

In this paper, the Anderson method with depth n is derived, where depth n represents the value of the previous n iterations. The Anderson acceleration formats with depths of 1 and 2 are used to calculate neutron flux of the reactor core. We calculate Boron critical searching calculation of the first-cycle loading. The calculation results show that the Anderson method reduces the number of iterations by 20% and the calculation time by about 15% on average compared with the source Seidel iteration while ensuring the same convergence accuracy. This improves the efficiency of neutronics calculations and provides a theoretical basis for subsequent transport calculations or other fixed-point iteration acceleration methods.
Study on Influence of Nonlinear Characteristics of Laminated Rubber Bearings on Reactor Buildings Including SMR
Authors: Kitagawa Keito , Furuya Osamu , Okamura Shigeki
Published: November 2024

The development of small modular reactors (= SMR), which are safer and more rational than current nuclear power generation facilities, is underway. As a countermeasure against earthquakes, it is assumed that a laminated rubber bearing for seismic isolation system will be installed.

It is well known that laminated rubber bearing has nonlinear mechanical properties in a large deformation region.[1] Therefore, searching for conditions where the effects of the nonlinear mechanical properties of laminated rubber bearing are likely to appear through modal analysis. Then, a nonlinear time history response analysis and a floor response spectrum are calculated for the selected conditions. The results will evaluate the effects of the nonlinear mechanical properties of laminated rubber bearing on reactor buildings and internal equipment.

As a result of the evaluation, when the mass ratio of the base plate and the building is equal in the horizontal direction, the seismic isolation period is 2.00 s and the building vibration frequency is 4.00 Hz, and in the vertical direction, when the mass ratio is equal, the isolation frequency 20.0 Hz and the reactor building natural frequency 20.0 Hz, that was confirmed that the influence of nonlinear dynamic characteristics is noticeable.
United States NRC Modernization Efforts to Enable the Safe Use of Digital Instrumentation and Controls in Nuclear Power Plant Safety Systems
Authors: Darbali Samir , Taneja Dinesh , Martinez Rodriguez Erick , Blas Rodriguez Gilberto
Published: November 2024

In the United States (U.S.), licensees for operating nuclear power reactors and applicants for new and advanced reactor designs are pursuing the effective and efficient use of digital technologies for their instrumentation and control (I&C) systems. As such, it is necessary that the U.S. regulatory infrastructure for the safe implementation of digital I&C (DI&C) technology in nuclear power reactors is clear and efficient. Over the past few years, the U.S. Nuclear Regulatory Commission (NRC) staff, in collaboration with nuclear industry stakeholders, has extensively modernized its DI&C regulatory infrastructure to enable the safe and secure use of DI&C technology in nuclear power plant safety systems and components. This paper will describe the NRC’s vision for a modernized DI&C regulatory infrastructure and the significant accomplishments from recent years to improve the clarity and reliability of the DI&C regulatory infrastructure. This paper will also describe ongoing regulatory improvement activities as well as ongoing and planned NRC staff research efforts related to the use of new technologies in nuclear power plant safety systems.
Code-to-Code Verification of Thermal Hydraulic Subchannel Code LINDEN
Authors: Wang Zixuan , Zhu Yuanbing , Wang Yan
Published: November 2024

The subchannel code LINDEN is developed as a dedicated numerical tool for thermal-hydraulic analyses of a pressurized water reactor (PWR) under varying operating conditions. To fully achieve the development goals of LINDEN, rigorous verification and validation (V&V) work should be included in preparation for its intended applications in engineering practice. This research focuses on a code-to-code verification of the code, where a top-down verification strategy has been adopted. The main features and basic models of LINDEN were first introduced. In order to verify the concerned models, a verification matrix for separate-effect test and integral-effect test with different typical thermal-hydraulic scenarios was designed. The test cases involved a typical single channel in a PWR primary circuit and a 5 × 5 rod bundle under both steady-state and transient conditions. The simulation results of several key thermal-hydraulic parameters were then compared with those from the state-of-the-art subchannel code CTF. The calculation results of LINDEN were in good agreement with those of CTF under different test cases, and only the void prediction of LINDEN is on the lower side compared to CTF’s, which could be attributed to different interface mass exchange models taken in the two codes. In summary, the code-to-code based assessment work in this study has confirmed that the basic models are correctly implemented and performed as expected.
Customising a System Code for the Analysis of the Thermal-Hydraulic Behaviour of a Supercritical Pressure Light Water Small Modular Reactor
Authors: Chaaraoui Omar , Pucciarelli Andrea , Ambrosini Walter , Otic Ivan , Schulenberg Thomas , Allison Chris , Fu Zheng
Published: November 2024

The paper reports about the work performed in customizing the RELAP/SCDAPSIM code features for an easier assessment of a conceptual design of a Small Modular Reactor (SMR) operating at supercritical pressure proposed by Schulenberg and Otic [13] in the frame of the EU ECC-SMART Project. First unsuccessful attempts to make use of an NRC version of the RELAP5 code in the analysis of the thermal-hydraulic behaviour of the SCW SMR revealed numerical difficulties at the transition from supercritical to subcritical pressures. This suggested to activate a cooperation for customising an already existing version of the RELAP/SCDAPSIM code, aiming to overcome similar numerical problems and to implement heat transfer correlations in principle more appropriate for supercritical pressure conditions. The improved version of the code, featuring a user defined generalised correlation for heat transfer encompassing several of the presently available literature proposals, was applied in predicting rod-bundle experiments performed by Razumovskiy et al. [16–17] and in analysing the behaviour of the seven core flow passage reactor proposed in [13]. In the paper, the present capabilities of the code are discussed in front of the obtained results and perspectives for future developments are suggested.
Experimental Study on Metal Jet Spreading on Substrate With Roughness
Authors: Xu Yihua , Yokoyama Ryo , Suzuki Shunichi
Published: November 2024

The behavior of molten corium, particularly when it impinges upon the containment substrate and the further spreading, is important in determining the integrity of the containment structures. In nuclear power plants (NPPs), substrates typically display a variety of surface textures; however, the impact of substrate roughness on corium behavior remains inadequately explored. In this study, the influence of substrate roughness on the corium spreading behavior is investigated. A series of scaled experiments were conducted using Wood’s metal as corium simulant impacting substrates of different roughness levels. The heated corium simulant is discharged on the substrate (sandpaper or concrete) and this process is recorded by cameras. Based on the experimental results obtained, a model is proposed to predict spreading area considering both corium flow rate and substrate roughness. It is concluded that increased substrate roughness generally reduces the spreading area of corium. The results of these experiments provide valuable insights into how surface roughness influences the spreading behavior of corium, offering essential data for enhancing reactor safety measures and containment strategies.
Multi-Objective Optimization Design for Nuclear-Coupled Distributed Multi-Energy System in Alpine Region
Authors: Ren Xiaoxiao , Jiang Chao , Wang Jinshi , Yang Sifan , Zhao Quanbin , Yan Junjie
Published: November 2024

The alpine regions are characterized by its remote location, cold climate and limited conventional energy, which presents considerable challenges in ensuring reliable electricity and heating supply. To this end, a nuclear-coupled distributed multi-energy system (N-DMES) is proposed. To attain the optimal configuration and operation of N-DMES, a multi-objective optimization model is developed with net present cost, shortage of electricity and renewable energy power generation as objective functions. Meanwhile, the improved multi-objective grasshopper optimization algorithm is utilized for the model solving. Besides, this system is compared with a diesel-coupled distributed multi-energy system (D-DMES). This paper takes a market town in an alpine region as a case study to assess the effectiveness and feasibility of the proposed N-DMES. Simulation results indicate that the designed N-DMES can satisfy the users’ electricity demands. N-DMES exhibits slightly lower economic performance and renewable energy consumption compared to D-DMES. However, N-DMES surpasses D-DMES in terms of environmental friendliness and reliability. The minimum load factor of MMR and renewable energy capacity have a certain impact on the system performance.
Numerical Simulation on the Thermal Hydraulic Characteristics in Pool-Type Fast Reactor Based on the New-Designed Passive Dynamic Residual Heat Removal Valve
Authors: Qu Yuanshu , Zhang Yuhao , Zhao Haiqi , Lu Daogang
Published: November 2024

The passive features of the Emergency Heat Removal System (EHRS) is a crucial component of the reactor’s safety design, and its passive safety features has a significant impact on its performance during accidents. The coolant in the new sodium-cooled fast reactor enters the core directly through the control valve and heat transfer pipe during accident conditions. Because the decay heat exchanger (DHX) is equipped with a check valve at the outlet position. This valve can be opened automatically in the event of an accident, improving the reactor’s passive safety features. For the new design model of sodium-cooled fast reactor, a calculation model of new residual heat removal system calculation model is established with a new ball check valve by CFD software. The UDF program was used to simulate the opening and closing of the check valve by jointly simulating FLUENT dynamic mesh technology and transient dynamics. This allowed the spool of the new ball valve to move freely with the fluid. Simulation calculations were conducted to determine the thermal and hydraulic characteristics of the ball check valve under normal operation and accidental shutdown conditions. Additionally, the dynamic process of temperature change was analyzed after opening the passive safety system under accidental conditions to evaluate the effect of the control valve. The results indicate that the new control valve is passively opened due to the temperature difference and buoyancy force. Additionally, the fluid in the DHX undergoes natural circulation throughout the entire core, gradually recovering from standby power to full power operation. When the flow rate of the pump gradually decreases, it would take over the task of cooling the core. This not only enhances the passive safety features of the EHRS but also efficiently conducts the heat of the reactor, and effectively discharges the residual heat of the core.
Bamboo-Frame: An Automatic Modeling Tool for the Two-Step Reactor Core Physics Analysis
Authors: Zhou Yuancheng , Li Yunzhao , Li Yisong , Liang Yilin , Zhang Hengrui , Zhou Shilong , Wang Weiguo , Ou Yuxiang
Published: November 2024

Conventional method of reactor core analysis pivots on the two-step methodology requires the users to have expert understanding on the methodology, to provide significant manual input, and to maintain substantial data consistency. Thereby, the calculation process turns out to be complex and error-prone. In light of this, we developed Bamboo-Frame to automate the modeling procedure in Pressurized Water Reactor (PWR) core analysis. This innovative tool requires users to provide only structural and operational parameters, while effectively managing complex tasks such as lattice recognition, thermal expansion, state matrix setting, core nodes division, and input file generation. This culminates in a user-friendly visualization system, thus significantly increasing accessibility and reducing manual workload.

The application of Bamboo-Frame to CNP650, a PWR with a full power output of 1930 MW, showcased its capability to handle the modeling of 52 fuel lattices and numerous reflector lattices. The software’s robustness and precision were evident when compared to the case without Bamboo-Frame, with the input file size dramatically reduced from 38.6MB to 168KB, underscoring its efficiency and the potential to reduce human error. Validation through startup physical test simulations and power history following simulations proved its remarkable accuracy within industrial standards, alongside statistical analysis demonstrating compliance with engineering standards.