bluuebunny/crossref_metadata_2025_split huggingface dataset:
Study on the Oxidation/Corrosion Behavior of Small Modular Lead-Bismuth-Cooled Fast Reactor Summer
Authors: Zhang Junjia , Zhang Kefan , Chen Hongli 
Published: November 2024

Abstract
The issue of corrosion is one of the constraints on the safe operation of the Small Modular Lead-cooled Fast Reactor (SUMMER). In order to understand the oxidation/corrosion behavior of SUMMER during operation and optimize the design to ensure its safe operation, a simulation analysis program, KMC-SUBtra-MC, was employed to simulate SUMMER. The appropriate oxygen control range was theoretically derived, and simulations were conducted at an oxygen concentration of 1 × 10−6 wt.% to calculate the oxidation film thickness, corrosion thickness, and outlet oxygen concentration for both the hottest and average components. It was observed that SUMMER can maintain a dual-phase oxide film structure during operation, and the axial distribution of the oxidation film thickness is temperature-dependent. Oxygen depletion occurred during the initial stages of operation. Pre-oxidation of SUMMER components was found to improve the oxygen depletion situation and reduce the pressure in the oxygen control system.
Study on the Remelting Process of the Debris Bed in the Lower Head of Reactor Pressure Vessel Based on Lattice Boltzmann Method
Authors: Shi Shang , Li Liangxing , Ma Weimin , Zeng Xiao , Yuan Yidan , Lei Zhenxin , Xiang Zutao , Xu Xiangyang 
Published: November 2024

Abstract
The retention of core melt (corium) in the lower head of the reactor pressure vessel (RPV) has been considered as a severe accident management strategy to maintain the RPV integrity of a light water reactor. To study the debris bed remelting process in the lower head of the reactor pressure vessel, as well to explore the influence of external cooling on the debris bed remelting process, the Lattice Boltzmann Method (LBM) is employed to simulate the remelting process of the debris bed. The Lattice Boltzmann Method, as a powerful numerical method for simulating fluid flow and complex physical processes, has been widely used in the solution of solid-liquid phase change problems in recent years. Thermal Lattice Boltzmann Method (TLBM) based on total enthalpy is adopted to handle the latent heat in the phase change process, and the Immersed Boundary Method (IBM) is used to account for the velocity and boundary conditions of the solid-liquid phase interface. In addition, the calculation results from the present LBM model are also compared with the experimental data based on the COREM experimental system which is design and constructed to investigate the melting process of a debris bed packed with multi-component particles. The simulation results and experimental results have good consistency in the natural convection phenomenon during the melting process, which is been simulated successfully.
Influence of Multi-Hole Sparger Geometry on the Chugging Regime
Authors: Berti Luca , Lo Frano Rosa , d’Errico Francesco , Aquaro Donato 
Published: November 2024

Abstract
Several experimental tests have been carried out at the University of Pisa using the Large-Scale Experimental Facility simulating the behaviour of the Vacuum Vessel Pressure Suppression System of ITER fusion reactor.
The experiments were carried out by injecting steam produced by an electric steam generator through a multi-hole sparger into a condensation tank, known as Experimental Test Tank, containing 55 m3 of water. Two spargers called sparger A (a reduced scale of ITER sparger) and sparger B (a full scale of ITER sparger) were used during the experimental campaign. The geometry of the two spargers differs for the arrangement of the holes at the external (injecting) surface.
This study compares the behavior of the two spargers by analyzing two experimental tests. The unstable chugging regime was also considered.
The image analysis of the videos permitted the comparison of the steam bubble dynamics.
The geometry of sparger B leads to the coalescence of the entire steam mass, while the sparger A developed two distinct steam bubbles which do not coalesce together.
The analysis of the strain gauges and accelerometer signal allowed to compare the structural-dynamic response of the steam bubble collapse. This preliminary analysis showed the strong influence of the sparger geometry on the steam bubble dynamics and on the developed load on the sparger.
SIMMER-III Code Simulation of High-Pressure Water-Lead Interaction in Westinghouse’s LEWIN Test Facility
Authors: Bellomo Alessandro , Massone Mattia , Gianfelici Simone , Martini Fabio , Lee Sung Jin , Tarantino Mariano , Galleni Francesco , Pucciarelli Andrea , Pesetti Alessio 
Published: November 2024

Abstract
The Lead-cooled Fast Reactor (LFR) is one of the six advanced reactor system types selected in the Generation-IV (Gen IV) program. Westinghouse (WEC) is developing a highly simplified, passively safe, medium-size, economic Gen-IV LFR as its next-generation utility-scale nuclear power plant. Designed as a pool-type reactor, the Westinghouse LFR has all primary components located inside the reactor vessel (RV). The heat transfer from the primary coolant to the secondary side is accomplished through three primary heat exchangers (PHEs).
The PHE failure is one of the safety events considered in designing the Westinghouse LFR. Therefore, the transient behavior of the molten lead pool following PHE failure should be investigated to evaluate its consequences and to adopt effective mitigation measures. Based on the secondary system considered in the WEC LFR conceptual design, a high-pressure water injection into molten lead is considered for the characterization of coolant-coolant interaction (CCI) during a postulated PHE failure accident scenario.
In the framework of the collaboration between Westinghouse and ENEA, a separate effect testing (SET) facility named LEWIN (LEad-to-Water INteraction) was designed and built, with the aim of identifying and quantifying the main phenomena that occur during the high-pressure water injection into molten lead.
To support the conceptual design and experimental pre-test phase, the SIMMER-III (S-III) computer code was used to model the interaction vessel, the injection line, and the dump line. The choice of this code is justified by its distinctive fluid-dynamics features: it uses two-dimensional meshes to simulate a multi-velocity field with multiphase and multicomponent materials. However, since the original version of the S-III code cannot simulate two different types of coolant at the same time, code modifications have been introduced to enable modeling of the lead-water interaction.
This paper aims to assess the capability of SIMMER in simulating the main phenomena expected to take place during the experimental transients in LEWIN, and hence to illustrate the pioneering role the code can play, especially in studying the phase change phenomenology in lead-water thermal-hydraulics systems. The simulation results show the flashing of the water injected into the molten lead, the growth of water vapor bubbles in the lead pool, the lead pool swelling, and the lead sloshing motion. The pressure peak, onset of a choked flow, and pressurization of the cover gas region can be observed as well.
This activity has also the objective of supporting a systematic validation and verification (V&V) program for the SIMMER code assessment based on test problems involving lead, lead-bismuth eutectic alloy, and water systems, to advance the code as a next-generation standard tool for LFR safety analysis.
Progress in Isolation Analysis and Experimental Research of HPR1000 Nuclear Island Plant
Authors: Shi Chencheng , Chen Jian , Sun Xiaoying , Yang Xiaoyi , Ren Hehuan 
Published: November 2024

Abstract
At present, the PGA of the standardized design site of HPR1000 is 0.3g, which can meet the seismic requirements of the plant site at home and abroad. However, domestic nuclear power plant sites are scarce resources. When plant sites with higher intensity earthquake appear in the future, the seismic isolation technology can effectively reduce the seismic action on the superstructure and equipment to the desired level without being limited by the design ground motion size of the plant site, which can not only improve the safety and economy of HPR1000, but also broaden the application scope of HPR1000 standardized design in plant site. China Nuclear Power Engineering Company (CNPE) has carried out research on seismic isolation technology for nuclear power plants, and has successfully applied it in nuclear safety related plant. The main research includes: design and analysis of isolation scheme, influence analysis of soil-structure interaction on isolated plant, influence analysis of commercial aircraft impact on isolated nuclear island plant, and shaking table test of isolated nuclear safety related plant.
Analysis of the Dynamic Behaviour of a Nuclear Containment Structure Under Missile Impact
Authors: Lo Frano Rosa , Cancemi Salvatore Angelo , Angelucci Michela , Pugliese Giovanni 
Published: November 2024

Abstract
The evaluation of the integrity of the NPP against a missile impact requires considerable attention because of the complexity of the accident scenario and consequences it may cause. To assess whether such type of thread may determine the failure of the safeguard system, the effects of both the impact force and the resistance force must be determined.
This study deals with the currently used general procedures and criteria. Particularly, it focuses on the evaluation of global and local effects caused by an impacting missile on the reinforced concrete structural elements, like the containment system.
To the aim, a numerical approach based on the use of the finite element (FE) code was adopted. As the analysis of reinforced concrete is made complex by the several arising dominant energy absorbing and failure modes mechanisms, a methodology which was validated with reference to experimental data available in the open literature from large-scale impact tests was employed. Therefore, a 3D FE model of the RCS was implemented with structural 3-D Solid element to represent the dynamic interaction occurring at the impact surface.
The strain-rate effects are considered through the dynamic increase factor (DIF) to account for strain-rate hardening effects on both deformation and failure; for the steel behavior the Cowper-Symonds’ model was assumed.
Results showed that at the instant of the impact, the intense shock wave that characterize the instant of the projectile-target impact is responsible of the cracking, and penetration of the RCS wall. For a striking velocity of about 150 m/s the wall penetration extends over about 80 mm.
Development and Verification of a Few-Group Parameters Calculation Code TMSR-LINK for Molten Salt Reactor
Authors: Wang Kailong , Cui Yong , Zou Chunyan , Chen Jingen , Cai Xiangzhou 
Published: November 2024

Abstract
Assembly few-group cross-sections are important parameters for nuclear design of reactor with the ‘two-step’ strategy based on deterministic theory. The unique physical mechanism and operation mode of liquid-fueled Molten Salt Reactor (MSR) make the calculation method of assembly few-group cross-sections different from that of the traditional solid-fueled reactor. In this work, a few-group parameters calculation code for MSR named TMSR-LINK is developed based on OpenMC, and two single assembly benchmarks of pressurized water reactor and MSR are first verified and analyzed; Simultaneously, macro cross-section libraries of the Molten Salt Reactor Experiment (MSRE) are prepared and provided to the MSR specific neutronics/thermal-hydraulics (TH) coupling code TMSR3D based on advanced nodal method, by which the reactivity loss caused by fuel flow and temperature distributions of graphite and fuel salt in the hottest channel are calculated and compared with the experimental data and the results from similar code; Finally, the steady-state characteristics of MSRE under different operation power are also probed. The results indicate that TMSR-LINK can provide a reasonable description for the benchmarks, which verified the accuracy of the developed code. The neutronics-TH coupling simulation results of the whole core for MSRE agree well with the experiments and exhibit a comparable precision against the similar code, this means that TMSR-LINK can provide accurate macro cross-section data for the MSR specific neutronics-TH coupling analysis code.
Evaporation of Alkali Metal Sodium Droplet in the Circular Tube
Authors: Tang Songsheng , Guo Kailun , Tian Shiyu , Ma Yugao , Zhao Jinkun , Su Guanghui , Qiu Suizheng , Tian Wenxi 
Published: November 2024

Abstract
High-temperature heat pipe is a passive and efficient heat transfer element, which is generally filled with a certain mass of alkali metal as the heat transfer medium, and utilizes vapor-liquid phase change to efficiently transfer heat from the evaporation section to the condensation section of the heat pipe. In the normal operation of high-temperature heat pipe, the alkali metal will experience evaporation in the evaporation section, vapor diffusion in the adiabatic section, condensation in the condensation section, and reflux under the action of capillary force of the wick structure and other complex heat and mass transfer behaviors. This study focuses on the evaporation behavior of sodium alkali metal inside a high-temperature heat pipe. First of all, an experimental rig is constructed to visualize the evaporation behavior of alkali metal sodium droplets, which mainly includes the alkali metal sodium purification system (to remove the kerosene and impurities inside the commercial sodium to ensure the high purity of sodium), the visual measurement system (to record the droplet morphology), and the constant-temperature and constant-pressure argon system (to provide a high-purity argon environment to avoid the chemical reaction between sodium and the water vapor and oxygen in the air during the experimental process and to provide different temperature and pressure environments for the evaporation of sodium). Then, the evaporation behavior of alkali metal sodium droplets in a circular tube with different wall temperatures and pressure is experimentally investigated by using the previously constructed experimental rig, and the morphological changes of the droplets during the evaporation process were recorded by a high-speed camera. After that, the image analysis software ImageJ is used to analyze the droplet morphology to obtain the change curves of droplet height, contact line length, and contact angle with time during the evaporation of sodium alkali droplets. And the curves are further analyzed to obtain the information of sodium droplet evaporation mode and evaporation rate. By comparing and analyzing the experimental data of sodium droplet evaporation from round tubes with different temperatures and ambient pressures, the influence of the temperature and ambient pressures on the evaporation behavior of sodium droplets is obtained. In this study, the first experimental data of sodium alkali droplet evaporation in a high-temperature heat pipe is obtained by visualization experimental means, which reveals the mechanism of sodium droplet evaporation and lays a foundation for further improvement of the existing heat pipe simulation model.
Optimising digital clinical consultations in maternity care: a realist review and implementation principles
Authors: Evans Catrin , Clancy Georgia , Evans Kerry , Booth Andrew , Nazmeen Benash , Sunney Candice , Clowes Mark , Jones Nia , Timmons Stephen , Spiby Helen 
Published: November 2024

ObjectivesThe COVID-19 pandemic has led to increased use of digital clinical consultations (phone or video calls) within UK maternity services. This project aimed to review the evidence on digital clinical consultations in maternity systems to illuminate how, for whom and in what contexts, they can be used to support safe, personalised and equitable care.DesignA realist synthesis, drawing on diverse sources of evidence (2010–present) from OECD countries, alongside insights from knowledge user groups (representing healthcare providers and service users).MethodsThe review used three analytical processes (induction, abduction and retroduction) within three iterative stages (development of initial programme theories; evidence retrieval and synthesis; validation and refinement of the programme theories).ResultsNinety-three evidence sources were included in the final synthesis. Fifteen programme theories were developed showing that digital clinical consultations involve different mechanisms operating across five key contexts: the organisation, healthcare providers, the clinical relationship, the reason for consultation and women. The review suggests that digital clinical consultations can be effective and acceptable to stakeholders if there is access to appropriate infrastructure/digital resources and if implementation is able to ensure personalisation, informed choice, professional autonomy and relationship-focused connections. The review found relatively less evidence in relation to safety and equity.ConclusionsDue to the complexity of maternity systems, there can be ‘no one-size fits all’ approach to digital clinical consultations. Nonetheless, the review distills four ‘CORE’ implementation principles: C—creating the right environment, infrastructure and support for staff; O—optimising consultations to be responsive, flexible and personalised to different needs and preferences; R—recognising the importance of access and inclusion; and E—enabling quality and safety through relationship-focused connections. Service innovation and research are needed to operationalise, explore and evaluate these principles, particularly in relation to safety and equity.PROSPERO registration numberCRD42021288702.
Assessing the impact of COVID-19 on HIV care cascade for people living with HIV in Ethiopia: a retrospective longitudinal study
Authors: Amhare Abebe Feyissa , Shen Mingwang , Zou Zhuoru , Xia Ruyi , Han Jing , Gao Liangmin , Zhang Lei 
Published: November 2024

ObjectiveThe study aimed to investigate the impact of COVID-19 on the cascade of HIV care for people living with HIV (PLHIV) in Ethiopia.DesignA retrospective longitudinal study.SettingThe study was conducted in North Showa Zone, Ethiopia, from pre-COVID-19 (January 2018–December 2019) and during COVID-19 (January 2020–December 2021).ParticipantsWe identified 61901 records from 3925 PLHIV, of which 23 848 were recorded during the pandemic.Main outcome measureWe investigated indicators from four stages of the HIV care cascade, including HIV screening and diagnosis, HIV care, HIV treatment and HIV disease progression, according to a WHO framework. The indicator changes were assessed with incidence rate ratios (IRRs).ResultsFor HIV screening and diagnosis, the monthly number of HIV tests experienced a 46% decline from 2520 to 1361 since the pandemic (IRR 0.553; 95% CI 0.546 to 0.561). For HIV care, the monthly number of consultations was reduced by 49.6% (from 1582 to 798) since the pandemic (IRR 0.591; 95% CI 0.581 to 0.601). Similarly, the monthly number of viral load tests was reduced by 42.8% (IRR 0.614; 95% CI 0.581 to 0.650). For HIV treatment, the number of antiretroviral therapy (ART) initiations was reduced by 27.8% and the number of ART adherence by 52.5% since the pandemic. For HIV disease progression, the monthly number of PLHIV achieving viral suppression was reduced by 61.6%, while HIV-related deaths doubled during the pandemic.ConclusionThe study highlights pandemic-induced disruptions in the cascade of care for PLHIV. Targeted interventions are necessary to protect PLHIV in public health emergencies.
Predictive factors associated with Bile culture positivity And phenotypiCal antIbiogram resistance patterns in patients taken to LaparOscopic cholecystectomy (BACILO): protocol for a prospective observational cohort study and development of a prognostic prediction model
Authors: Ramírez-Giraldo Camilo , Rodriguez Barbosa Carlos , Isaza-Restrepo Andrés , Avendaño-Morales Violeta , Rojas-López Susana , Van-Londoño Isabella 
Published: November 2024

IntroductionBile fluid is aseptic under normal conditions; however, in the presence of cholecystitis, its susceptibility to bacterial colonisation varies, with reported rates of 20%–70% of cases. This process is referred to as bactibilia and/or bacteriobilia and can be considered a secondary complication of biliary stasis and cholecystitis in general. In the management of acute cholecystitis, the antibiotic regimen should be prescribed based on the presumed pathogens involved, taking into consideration the risk factors for resistance patterns according to demographics and local exposure. The aim of this study is to determine the predictive factors for bile culture positivity and antibiotic resistance in patients who underwent laparoscopic cholecystectomy in the Méderi Hospital Network. We hope to develop a predictive model that allows us to better guide antibiotic therapy.Methods and analysisThis is a prospective observational cohort study with prognostic prediction model. Patients who will undergo laparoscopic cholecystectomy and have bile cultures taken in the Méderi Hospital Network during the study period will be included. The dependent variables will be positive bile culture and antibiotic resistance, and the predictive variables will be age, presence of diabetes, diagnosis of choledocholithiasis, diagnosis of cholecystitis and severity of cholecystitis according to the Tokyo criteria. The minimum sample size has been calculated at 703 patients. Follow-up will continue until a control appointment 15 days after the procedure. The primary outcomes are bile culture positivity and phenotypical antibiogram resistance. For each outcome, a multivariate logistic regression will be performed using frequentist and Bayesian prediction techniques.Ethics and disseminationThis study was approved by the Méderi network research department committee (CIMED) and by Universidad del Rosario’s Research Ethics Committee (CEI-UR; DVO005 2555-CV1837). Written informed consent is required for participation. The results will be disseminated through the submission of an academic article to a high-impact scientific journal, presentations at academic conferences, and sharing with our institution's faculty to inform antimicrobial therapy management based on local epidemiological data.Trial registration numberNCT06314399.