Influences of Evidence, Beliefs, and Emotion

Within the reasoning literature, most investigations of motivated reasoning, belief-biased reasoning and the effects of emotional material have all been conducted separately from each other. Motivated reasoning theories state that reasoning can be goal-directed, and all future processing is allocated towards achieving an end goal or justifying a position. Dual process theories of reasoning, on the other hand, allow for analytic thinking to discriminate between strong and weak arguments. Additionally, theories of emotion in reasoning state that emotional content can negatively impact future processing. Our goal was to investigate the interaction of argument strength, prior belief and emotional content in argument evaluation over the course of three experiments (N = 360). Participants completed questionnaires that involved reading conversation transcripts and ranking the strength of the evidence presented in the conversation. Conversations were varied on their argument strength, believability, and emotional content. Following the conversations, we asked participants to personally rank the believability and emotionality of the topics used within the experiment. We found that most participants were sensitive to the strength of the evidence presented in the conversations, but a small minority were more likely to appraise the evidence based previous beliefs. The impact of emotional versus neutral content was found to minimally impact the appraisal of presented evidence. These data suggest an explanation based on both motivated reasoning theories and dual process theories of reasoning. Most individuals were able to discriminate between strong and weak evidence, as predicted by dual process theories. However, some individuals were more sensitive to the believability of the presented statements and exhibited examples of belief bias phenomena. As motivated reasoning theories would predict, their appraisal of evidence may have been guided towards an end-goal that was congruent with their previous beliefs. Individual differences played a large role in our current findings, and future directions should investigate the driving forces behind these differences

ADRANOS: A numerical tool developed to analyse coolant operating conditions of the EU-DEMO divertor

In the context of the activities of the EUROfusion action, the University of Palermo has carried out a research campaign to evaluate the thermal-hydraulic performance of the EU-DEMO divertor Single-Circuit Cooling (SCC) option. Given the exceptional geometric complexity of this divertor design, the search for coolant operating conditions that comply with the applicable design constraints cannot be performed by relying on detailed 3D computational fluid-dynamic calculations. For this purpose, the Advanced Divertor paRametric Analysis for coolaNt Operating Scenarios (ADRANOS) code has been developed. It is a novel numerical tool capable of quickly assessing the thermofluid-dynamic behaviour of the divertor cooling circuit with reduced computational cost, predicting the divertor performance map at different coolant inlet conditions and mass flow rates, and allowing for the effortless study of different circuit topologies. This study introduces the ADRANOS modelling approach, describes its validation process, and demonstrates its application to various configurations of the SCC divertor option. The results obtained showed that it is possible to find suitable coolant operating conditions characterized by low temperature and high pressure, posing a challenge for the adoption of Eurofer as a structural material

Development of a thermal-hydraulic model of the EU-DEMO Water Cooled Lithium Lead Breeding Blanket Primary Heat Transport System

The EUROfusion consortium is developing the project of a DEMOnstration Fusion Reactor (EU-DEMO) which would follow ITER in the pathway towards the quest for the exploitation of fusion energy. EU-DEMO has been conceived to deliver net electric power to the grid. Therefore, proper critical evaluations of the tokamak cooling and power conversion systems are needed because they play a pivotal role in the design and licencing of the overall plant. The EU-DEMO reactor will be based on the tokamak concept and, as such, it is supposed to undergo a pulsed duty cycle under normal conditions, which might challenge the qualified lifetime of the main equipment inducing undue thermal and mechanical cycling. Moreover, the EU-DEMO plasma control strategy postulates the possible occurrence of planned and off-normal plasma overpower transients that might jeopardise the structural integrity of the plasma facing components. It is, therefore, of paramount importance to have appropriate tools to reproduce the thermal-hydraulic behaviour of tokamak cooling systems during major operational and accidental scenarios in a realistic and reliable way. In this context, University of Palermo in cooperation with EUROfusion has developed a finite volume model of the Primary Heat Transport System (PHTS) feeding the EU-DEMO Water Cooled Lithium Lead Breeding Blanket (WCLL BB). The activity has been led following a theoretical–computational approach based on the adoption of the TRACE thermal-hydraulic system code. Particular attention has been paid to capturing all the main geometrical, hydraulic and heat transfer features characterising both in-vessel and ex-vessel components. Preliminary analyses have also been carried out to check the code's predictive potential in fusion relevant applications. Models, assumptions, and outcomes of the analyses are herewith reported and critically discussed

Design and optimization of Artificial Neural Networks for the modelling of superconducting magnets operation in tokamak fusion reactors

In superconducting tokamaks, the cryoplant provides the helium needed to cool different clients, among which by far the most important one is the superconducting magnet system. The evaluation of the transient heat load from the magnets to the cryoplant is fundamental for the design of the latter and the assessment of suitable strategies to smooth the heat load pulses, induced by the intrinsically pulsed plasma scenarios characteristic of today's tokamaks, is crucial for both suitable sizing and stable operation of the cryoplant. For that evaluation, accurate but expensive system-level models, as implemented in e.g. the validated state-of-the-art 4C code, were developed in the past, including both the magnets and the respective external cryogenic cooling circuits. Here we show how these models can be successfully substituted with cheaper ones, where the magnets are described by suitably trained Artificial Neural Networks (ANNs) for the evaluation of the heat load to the cryoplant. First, two simplified thermal-hydraulic models for an ITER Toroidal Field (TF) magnet and for the ITER Central Solenoid (CS) are developed, based on ANNs, and a detailed analysis of the chosen networks' topology and parameters is presented and discussed. The ANNs are then inserted into the 4C model of the ITER TF and CS cooling circuits, which also includes active controls to achieve a smoothing of the variation of the heat load to the cryoplant. The training of the ANNs is achieved using the results of full 4C simulations (including detailed models of the magnets) for conventional sigmoid-like waveforms of the drivers and the predictive capabilities of the ANN-based models in the case of actual ITER operating scenarios are demonstrated by comparison with the results of full 4C runs, both with and without active smoothing, in terms of both accuracy and computational time. Exploiting the low computational effort requested by the ANN-based models, a demonstrative optimization study has been finally carried out, with the aim of choosing among different smoothing strategies for the standard ITER plasma operation

Thermofluid-dynamic assessment of the EU-DEMO divertor single-circuit cooling option

Until 2019, the thermo-hydraulic development of the EU-DEMO divertor was based on the “double-circuit” concept, in which two independent cooling circuits served by two different Primary Heat Transfer Systems were used to cool the Plasma-Facing Components (PFC) and the Cassette Body (CB). During the Divertor Final Design Review Meeting, held in May 2020, the possibility to adopt a single cooling circuit to serve both components was suggested. This new cooling circuit was originally conceived with the aim of simplifying remote maintenance, with potential benefits for some aspects of safety and balance of plant design and integration. During the years from 2020 to 2022, in the framework of the Work Package DIV 1 - “Divertor Cassette Design and Integration” of the EUROfusion action, University of Palermo and ENEA carried out a research campaign focussed on the preliminary thermofluid-dynamic assessment of this new concept, highlighting its strengths and weaknesses. The research campaign was carried out following a theoretical–computational approach based on the finite volume method and adopting the commercial computational fluid-dynamic code ANSYS-CFX. The steady-state thermal-hydraulic performances of the single-circuit DEMO divertor concept were assessed in terms of coolant pressure drop and flow velocity distribution, mainly in order to check coolant aptitude to provide a uniform and effective cooling to CB, shielding liner, reflector plates, PFCs and the newly introduced neutron shields to improve the shielding of the vacuum vessel. Moreover, the margin against critical heat flux distributions among the plasma-facing channels were assessed by adopting appropriate correlations, to check the compliance with the applicable constraints. Models, loads and boundary conditions assumed for the analyses are herewith reported and critically discussed, together with the main results obtained

Thermomechanical and Thermofluid-Dynamic Coupled Analysis of the Top Cap Region of the Water-Cooled Lithium Lead Breeding Blanket for the EU DEMO Fusion Reactor

In the EU, the Water-Cooled Lithium Lead (WCLL) Breeding Blanket (BB) concept is one of the candidates for the design of the DEMO reactor. From the past campaign of analysis emerged that the thermal-induced stress led to the failure in the verification of the RCC-MRx structural criteria. Hence, in this paper the classic conceptual design approach, based on a pure FEM thermal and structural analysis, is compared to a coupled thermofluid-dynamic/structural one. Even though the coupled approach requires tremendous modelling effort and computational burden, it surely allows determining the thermal field with a higher level of detail than the FEM analysis. Therefore, in this work, the focus is put on the impact of a more detailed thermal field on the DEMO WCLL BB global structural performances, focusing on the Top Cap region of its Central Outboard Blanket segment. The obtained results have allowed confirming the soundness of the design solution of the Top Cap region, except for concerns arising on the mass flow rate distribution. Moreover, results have shown that, globally, the pure FEM approach allows for obtaining more conservative results than the coupled one. This is a positive outcome in sight of the follow-up of the DEMO WCLL BB design, as it will be still possible adopting the pure FEM approach to quickly down-select design alternatives, using the most onerous coupled approach to finalise the most promising

Hydraulic characterization of the full scale mock-up of the demo divertor outer vertical target

In the frame of the pre-conceptual design activities of the DEMO work package DIV-1 “Divertor Cassette Design and Integration” of the EUROfusion program, a mock-up of the divertor outer vertical target (OVT) was built, mainly in order to: (i) demonstrate the technical feasibility of manufacturing procedures; (ii) verify the hydraulic design and its capability to ensure a uniform and proper cooling for the plasma facing units (PFUs) with an acceptable pressure drop; and (iii) experimentally validate the computational fluid-dynamic (CFD) model developed by the University of Palermo. In this context, a research campaign was jointly carried out by the University of Palermo and ENEA to experimentally and theoretically assess the hydraulic performances of the OVT mock-up, paying particular attention to the coolant distribution among the PFUs and the total pressure drop across the inlet and outlet sections of the mock-up. The paper presents the results of the steady-state hydraulic experimental test campaign performed at ENEA Brasimone Research Center as well as the relevant numerical analyses performed at the Department of Engineering at the University of Palermo. The test facility, the experimental apparatus, the test matrix and the experimental results, as well as the theoretical model, its assumptions, and the analyses outcomes are herewith reported and critically discussed

Root vacuolar sequestration and suberization are prominent responses of Pistacia spp. rootstocks during salinity stress

Understanding the mechanisms of stress tolerance in diverse species is needed to enhance crop performance under conditions such as high salinity. Plant roots, in particular in grafted agricultural crops, can function as a boundary against external stresses in order to maintain plant fitness. However, limited information exists for salinity stress responses of woody species and their rootstocks. Pistachio (Pistacia spp.) is a tree nut crop with relatively high salinity tolerance as well as high genetic heterogeneity. In this study, we used a microscopy-based approach to investigate the cellular and structural responses to salinity stress in the roots of two pistachio rootstocks, Pistacia integerrima (PGI) and a hybrid, P. atlantica x P. integerrima (UCB1). We analyzed root sections via fluorescence microscopy across a developmental gradient, defined by xylem development, for sodium localization and for cellular barrier differentiation via suberin deposition. Our cumulative data suggest that the salinity response in pistachio rootstock species is associated with both vacuolar sodium ion (Na+) sequestration in the root cortex and increased suberin deposition at apoplastic barriers. Furthermore, both vacuolar sequestration and suberin deposition correlate with the root developmental gradient. We observed a higher rate of Na+ vacuolar sequestration and reduced salt-induced leaf damage in UCB1 when compared to P. integerrima. In addition, UCB1 displayed higher basal levels of suberization, in both the exodermis and endodermis, compared to P. integerrima. This difference was enhanced after salinity stress. These cellular characteristics are phenotypes that can be taken into account during screening for sodium-mediated salinity tolerance in woody plant species