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To optimize the performance of catalytic materials, it is paramount to elucidate the dependence of the chemical reactivity on the atomic arrangement of the catalyst surface. Therefore, identifying the nature of the active sites that provide optimal binding of reaction intermediates is the first step toward a rational catalyst design. In this work, we focus on the oxygen reduction reaction (ORR), an essential constituent of several energy provision and storage devices. Among the state-of-the-art ORR catalysts are platinum (Pt) and its alloys. The latter benefit from the so-called ligand and strain effects, which influence the electronic properties of the surface. Here, we “visualize” the active sites on Pt3Ni(111) in an acidic medium with a lateral resolution in the nanometer regime via an in-situ technique based on electrochemical scanning tunnelling microscopy. In contrast to pure Pt, where the active sites are located at concave sites close to steps, Pt3Ni(111) terraces contain the most active centres, while steps show activity to a comparable or lesser extent. We confirm the experimental findings by a model based on alloy- and strain-sensitive generalized coordination numbers. With this model, we are also able to assess both the composition and the geometric configuration of optimal catalytic active sites on various Pt alloy catalysts. In general, the interplay of ligand effects and lattice compression resulting from the alloying of Pt with 3d transition metals (Ti, Co, Ni, Cu) gradually increases the generalized coordination number of surface Pt atoms, thereby making (111) terraces highly active. This combination of theoretical and experimental tools provides clear strategies to design more efficient Pt alloy electrocatalysts for oxygen reduction. The authors cordially thank Mr Karl Eberle for his valuable assistance in the sample preparation and Mr Kun-Ting Song and Dr Batyr Garlyyev for helping with some of the electrochemical experiments. R. M. K., R. W. H., B. G. and A. S. B. acknowledge financial support from the Deutsche Forschungsgemeinschaft (DFG), in the framework of the project BA 5795/6-1. A. R. acknowledges funding by the DFG, project number 453903355. R. M. K., R. W. H., B. G., A. S. B., K. S., Y. B., J. V. B., and F. A. appreciate funding from the DFG through the Excellence Cluster “e-conversion”, EXC 2089/1-390776260. The grants RTI2018-095460-B-I00, María de Maeztu (MDM-2017-0767) and Ramón y Cajal (RYC-2015-18996) were funded by MCIN/AEI/10.13039/501100011033 and the European Union. This work was also partly funded by Generalitat de Catalunya 2017SGR13. The use of supercomputing facilities at SURFsara was sponsored by NWO Physical Sciences, with financial support from NWO. RMK, TOS and ASB acknowledge funding from the European Union's Horizon 2020 research and innovation programme under grant agreement HERMES No. 952184.

The paper introduces a novel approach for mitigating CO2 emissions in blast furnaces by integrating top gas recycling, an oxy-fuel regime, power to gas, and biomass pyrolysis. Various case studies were conducted, involving the adjustment of pyrolysis temperatures (300 °C, 500 °C, 700 °C, and 900 °C) and varying the quantity of blast furnace gas directed to methanation for carbon recycling. Pinus radiata, abundant and cost-effective in Chile and Spain, was chosen as the biomass source. The integration was modeled using the extended operating line methodology and evaluated through 12 key performance indicators, such as flame temperature, coke consumption, CO2 emissions, and specific primary energy consumption per unit of CO2 avoided. Optimal performance was observed with pyrolysis at 700 °C and no blast furnace gas recycled through methanation. This configuration achieved a 58 % reduction in CO2 emissions, with an energy consumption of 9.8 MJ/kgCO2, and obviated the need for geological storage. Comparing this innovative proposal with other oxygen blast furnace approaches from the literature revealed a 13 percentage point improvement in CO2 reduction over the second-best alternative. Additionally, the required electrolysis capacity, influencing capital expenditure, was 57 % lower, and energy consumption was reduced by 44 %.

This paper presents a novel concept of Power to Gas in an oxygen blast furnace, through blast furnace gas methanation and direct H2 injection. The PEM electrolyser produces H2, which reacts with the CO and CO2 from the blast furnace gas forming synthetic natural gas. The latter gas is injected into the blast furnace, closing a carbon loop and avoiding CO2 emissions. A parametric analysis is performed to vary the H2:CO2 ratio in the methanation reaction. Different ratios are simulated and compared, among of which the most representative are: (i) 2.5, where unreacted CO2 is directly recycled with the synthetic natural gas; (ii) 4, where stoichiometric conditions are found and the synthetic gas is composed mostly by CH4; and (iii) 8, where an excess of H2 is found in the synthetic gas; and (iv) an infinite ratio, where only H2 is injected in the blast furnace. In the latter, the methanation plant is not required, and no synthetic natural gas is produced. The results show that low H2:CO2 ratios perform poorly, involving high PEM sizes and high costs but only a 5% of CO2 avoidance (compared to conventional blast furnaces). A H2:CO2 ratio of 4 and full H2 injection results in higher reduction of CO2 emissions (33.8 % and 28.6%) with carbon abatement costs of 260 and 245 €/tCO2, respectively.

Abstract Sodium-cooled Fast Reactors and Lead-cooled Fast Reactors have been selected by the Sustainable Nuclear Energy Technology Platform as technologies that can meet future European energy needs. To achieve the requested level of safety for these reactor technologies and to minimize the increase in the costs due to additional safety measures, accurate and reliable nuclear data are necessary. The objective of this work has been to analyse and improve the nuclear data required for the development, safety assessment and licensing of SFRs and LFRs, reducing the uncertainties in the reactor integral responses due to the uncertainties in nuclear data, in order to reach the target accuracies defined by researchers, industry and regulators. To that end, target accuracy and data assimilation analyses have been performed to identify nuclear data weaknesses and to reduce the uncertainties of integral safety-related parameters due to neutron induced nuclear data. As a result of this work, nuclear data needs for advanced SFRs and LFRs have been identified, improvements of existing nuclear data libraries have been suggested, nuclear data have been adjusted and uncertainties in reactor integral parameters have been reduced, meeting target accuracies after adjustment.

[EN] The mechanical vibrations of fuel assemblies have shown to give high levels of neutron noise, triggering in some circumstances the necessity to operate nuclear reactors at a reduced power level. This behaviour can be modelled using the neutron noise diffusion approximation in the frequency-domain. This work presents an extension of the finite element method code FEMFFUSION, to simulate mechanical vibrations in hexagonal reactors in the frequency domain. This novel strategy in neutron noise simulation is based on introducing perturbations on the edges of the cells associated with the vibrating fuel assemblies, allowing to model the movement of these fuel assemblies accurately and efficiently, without the necessity of using locally refined meshes. Numerical results verify the edge-wise methodology in the frequency-domain against the usual cell-wise frequency-domain model and the time-domain model. The edge-wise frequency-domain methodology has also been compared to other neutronic codes, as CORESIM and PARCS. This project has received funding from the Euratom research and training program 2014-2018 under grant agreement No 754316.

The assessment of radiation fields in the lithium loop pipes and dump tank during the operation were performed for International Fusion Materials Irradiation Facility – DEMO-Oriented NEutron Source (IFMIF-DONES) in order to obtain the radiation dose-rate maps in the component surroundings. Variance reduction techniques such as weight window mesh (produced with the ADVANTG code) were applied to bring the statistical uncertainty down to a reasonable level. The biological dose was given in the study, and potential shielding optimization is suggested and more thoroughly evaluated. The MCNP Monte Carlo was used to simulate a gamma particle transport for radiation shielding purposes for the current Li Systems’ design. In addition, the shielding efficiency was identified for the Impurity Control System components and the dump tank. The analysis reported in this paper takes into account the radiation decay source from and activated corrosion products (ACPs), which is created by d-Li interaction. As a consequence, the radiation (resulting from ACPs and Be-7) shielding calculations have been carried out for safety considerations.

The Am241(n,¿) cross section has been measured at the n-TOF facility at CERN using deuterated benzene liquid scintillators, commonly known as C6D6 detectors, and time-of-flight spectrometry. The results in the resolved resonance range bring new constraints to evaluations below 150 eV, and the energy upper limit was extended from 150 to 320 eV with a total of 172 new resonances not present in current evaluations. The thermal capture cross section was found to be sth=678±68 b, which is in good agreement with evaluations and most previous measurements. The capture cross section in the unresolved resonance region was extracted in the remaining energy range up to 150 keV, and found to be larger than current evaluations and previous measurements. © 2014 American Physical Society.