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1. Characterization of fresh EMPIrE and SEMPER FIDELIS U(Mo)/Al fuel plates made with PVD-coated U(Mo) particles

Author

Iltis Xavière, Palancher Hervé, Allenou Jérôme, Vanni Florence, Stepnik Bertrand, Leenaers Ann, Van Den Berghe Sven, Keiser Dennis D., and Glagolenko Irina

Subjects
Nuclear engineering. Atomic power, TK9001-9401
Abstract

The HERACLES group and the US-DOE work jointly to develop dispersed U(Mo)/Al as LEU fuel for conversion of high performance nuclear research reactors. Within this frame, two irradiation programs are in progress. In the first, EMPIrE, mini-plates are tested in the ATR reactor (USA) and in the second, SEMPER FIDELIS, full-size plates are irradiated in BR2 (Belgium). In both experiments, U(Mo)/Al plates with optimized microstructure are tested under high duty conditions. This paper focuses on analyses made at CEA Cadarache on seven fresh plates made of atomized particles, with or without Mo homogenization, and with ZrN coating. Five EMPIrE mini-plates and two SEMPER FIDELIS full-size plates were examined by optical microscopy (OM), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). A particular attention is paid to the integrity of the ZrN coating (thickness, cracks…) and to the U(Mo) particles microstructure.

Published
2018
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3. Contributions to the mechanistic understanding of the microstructural evolution in irradiated U-Mo dispersion fuel

Author

Salvato, Daniele, Smith, Charlyne A., Pavlov, Tsvetoslav R., Hanson, William A., Bawane, Kaustubh K., Bachhav, Mukesh N., Miller, Brandon D., Trowbridge, Tammy L., Gan, Jian, Giglio, Jeffrey J., Winston, Alexander J., Henley, Jody L., Robinson, Adam B., Keiser, Dennis D., Glagolenko, Irina Y., Ye, B., Mei, Z.-G., Jamison, Laura M., Hofman, Gerard L., Yacout, Abdellatif M., Van den Berghe, Sven, and Leenaers, Ann

Published
2024
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4. Effect of main and side chain chlorination on the photovoltaic properties of benzodithiophene-: Alt -benzotriazole polymers

Author

Bin, H, Angunawela, I, Ma, R, Nallapaneni, A, Zhu, C, Leenaers, PJ, Saes, BWH, Wienk, MM, Yan, H, Ade, H, and Janssen, RAJ

Subjects
Macromolecular and Materials Chemistry, Physical Chemistry, Materials Engineering, Physical Chemistry (incl. Structural)
Abstract

In developing organic semiconductor polymers for photovoltaic applications, chlorine substitution has become an effective strategy in replacing fluorine substitution to overcome the drawbacks of low yield and high cost, commonly associated with fluorination. In general, several molecular positions are available for chlorination. To obtain a clear understanding of the impact of chlorine substitution on the intrinsic polymer properties, an investigation of structure-property relationships is necessary. Herein, four donor-acceptor type polymers with the same conjugated backbone and flexible alkyl chains, but with chlorine atoms in different positions, are employed to systematically investigate the effect of the site of chlorination on the optoelectronic properties and photovoltaic performance. Substitution of fluorine by chlorine in the backbone slightly increases open circuit voltage (Voc) and fill factor (FF) of the solar cells but causes a loss of short-circuit current density (Jsc). The introduction of chlorine in the conjugated side chains, however, significantly improves Voc, FF, and power conversion efficiency, benefiting from a lower HOMO energy level, efficient and well-balanced transport properties, and superior nanoscale morphology. This journal is

Published
2020

5. Impact of SEM acquisition parameters on the porosity analysis of irradiated U-Mo fuel

Author

D. Salvato, C.A. Smith, B. Ye, Z.-G. Mei, A.M. Yacout, J. Van Eyken, B.D. Miller, D.D. Keiser, I.Y. Glagolenko, J.J. Giglio, A.B. Robinson, A. Leenaers, J. Wight, and J.L. Henley

Subjects
U-Mo fuel, Fission gas bubbles, Porosity analysis, Scanning electron microscopy, Image analysis, Nuclear engineering. Atomic power, TK9001-9401
Abstract

In this study, the effect of various scanning electron microscope (SEM) imaging parameters, including voltage, beam current, and magnification, on the porosity analysis of U-Mo fuel was investigated by varying one parameter at a time during back-scattered electron (BSE) micrograph acquisition. Among the parameters assessed, porosity analysis is most sensitive to the SEM voltage. In the range from 5 kV to 30 kV, we reported relative differences as high as 30%, 10%, and 20% in the total porosity, average diameter, and pore density, respectively. Monte Carlo simulations were also performed to determine the influence of SEM voltage on the probing depths of back-scattered electrons. Increasing the voltage from 5 kV to 30 kV resulted in a change in probing depth from few tens of nanometers to several hundreds of nanometers. Portions of pores or entire pores residing below the polished plane that could not be seen at low voltages, and should not be counted for in the estimation of the open porosity, became visible at high voltages. Interestingly, in addition to allowing for a better estimation of the open porosity, the higher sensitivity to surface features at low voltages seems to reduce the number of pixels with intermediate gray levels in the final BSE image. This, in turn, could limit the ground for different interpretation by different analysts, and, as such, has the potential to facilitate a more consistent and uniform porosity analysis across different research laboratories.

Published
2023
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27. U-Si Based Fuel System

Author

Leenaers, Ann, primary, Wight, Jared, additional, Van den Berghe, Sven, additional, Ryu, Ho Jin, additional, and Valery, Jean-François, additional

Published
2020
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28. U-Al Based Fuel System

Author

Leenaers, Ann, primary, Wight, Jared, additional, Van den Berghe, Sven, additional, Ryu, Ho Jin, additional, and Valery, Jean-François, additional

Published
2020
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29. U-Mo Based Fuel System

Author

Leenaers, Ann, primary, Wight, Jared, additional, Van den Berghe, Sven, additional, Ryu, Ho Jin, additional, and Valery, Jean-François, additional

Published
2020
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34. Elements of RAFT Navigation

Author

Haven, Joris J, primary, Hendrikx, Matthew, additional, Junkers, Tanja, additional, Leenaers, Pieter J, additional, Tsompanoglou, Theodora, additional, Boyer, Cyrille, additional, Xu, Jiangtao, additional, Postma, Almar, additional, and Moad, Graeme, additional

Published
2018
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43. Effect of main and side chain chlorination on the photovoltaic properties of benzodithiophene

Author

Ruijie Ma, MM Martijn Wienk, Indunil Angunawela, Pieter J. Leenaers, He Yan, Asritha Nallapaneni, Haijun Bin, Bart W. H. Saes, Harald Ade, Chenhui Zhu, René A. J. Janssen, Molecular Materials and Nanosystems, ICMS Core, and EIRES Chem. for Sustainable Energy Systems

Subjects
chemistry.chemical_classification, Materials science, Benzotriazole, Open-circuit voltage, chemistry.chemical_element, General Chemistry, Polymer, Materials Engineering, Conjugated system, Physical Chemistry, Macromolecular and Materials Chemistry, Organic semiconductor, chemistry.chemical_compound, chemistry, Chemical engineering, Affordable and Clean Energy, Materials Chemistry, Side chain, Chlorine, polycyclic compounds, SDG 7 - Affordable and Clean Energy, Alkyl, SDG 7 – Betaalbare en schone energie, Physical Chemistry (incl. Structural)
Abstract

In developing organic semiconductor polymers for photovoltaic applications, chlorine substitution has become an effective strategy in replacing fluorine substitution to overcome the drawbacks of low yield and high cost, commonly associated with fluorination. In general, several molecular positions are available for chlorination. To obtain a clear understanding of the impact of chlorine substitution on the intrinsic polymer properties, an investigation of structure-property relationships is necessary. Herein, four donor-acceptor type polymers with the same conjugated backbone and flexible alkyl chains, but with chlorine atoms in different positions, are employed to systematically investigate the effect of the site of chlorination on the optoelectronic properties and photovoltaic performance. Substitution of fluorine by chlorine in the backbone slightly increases open circuit voltage (Voc) and fill factor (FF) of the solar cells but causes a loss of short-circuit current density (Jsc). The introduction of chlorine in the conjugated side chains, however, significantly improves Voc, FF, and power conversion efficiency, benefiting from a lower HOMO energy level, efficient and well-balanced transport properties, and superior nanoscale morphology. This journal is

Published
2020

44. The effect of alkyl side chain length on the formation of two semi-crystalline phases in low band gap conjugated polymers

Author

Mengmeng Li, René A. J. Janssen, MM Martijn Wienk, Pieter J. Leenaers, Molecular Materials and Nanosystems, Macromolecular and Organic Chemistry, ICMS Core, and EIRES Chem. for Sustainable Energy Systems

Subjects
chemistry.chemical_classification, Materials science, Photoluminescence, Band gap, General Chemistry, Polymer, Crystallography, chemistry, Phase (matter), Materials Chemistry, Side chain, SDG 7 - Affordable and Clean Energy, Absorption (chemistry), Solubility, Alkyl, SDG 7 – Betaalbare en schone energie
Abstract

The effect of the length of solubilizing alkyl side chains, ranging from hexyl to pentadecyl, on the formation and structure of two distinct semi-crystalline semiconductor phases, ß1and ß2, of a single conjugated polymer is investigated for a low band gap poly(diketopyrrolopyrrole-alt-quaterthiophene). Compared to ß1, the ß2phase exhibits a distinct redshifted absorption and an associated near infrared photoluminescence. The length of the alkyl side chains controls the formation of the ß1and ß2phases. Intermediate length alkyl side chains (nonyl and dodecyl) can selectively provide the ß1or ß2phase in solution and in semi-crystalline thin films, depending on the nature of the solvent used. For short side chains (hexyl) the ß2phase forms more readily while for long side chains (pentadecyl) the ß1phase is predominant. The kinetics of ß2phase formation is investigated and reveals a reduced growth rate when long alkyl side chains are present. X-ray diffraction reveals a closer p-p stacking distance for ß2than for ß1, consistent with its redshifted absorption and its higher mobility in field-effect transistors. The polymer with hexyl side chains adopts an edge-on orientation in thin films, while the longer alkyl chains induce a face-on orientation. Photovoltaic devices exhibit an additional near infrared spectral contribution to the photocurrent for the ß2phase. The study shows that the formation of the two polymorphs ß1and ß2is controlled by the alkyl side chains and the solubility that arises from them. Shorter side chains (lower solubility) favor ß2and longer side chains (higher solubility) ß1, and at intermediate lengths both phases can be formed.

Published
2020
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45. Holistic approach to investigate burn-up dependent thermal conductivity in dispersed fuel plates

Author

UCL - SST/ICTM/ELEN - Pôle en ingénierie électrique, UCL - SST/IMMC/IMAP - Materials and process engineering, Mai, T., Leenaers, A., Wight, J., Pardoen, Thomas, Van den Berghe, S., André, Nicolas, Coulombier, N., Raskin, Jean-Pierre, UCL - SST/ICTM/ELEN - Pôle en ingénierie électrique, UCL - SST/IMMC/IMAP - Materials and process engineering, Mai, T., Leenaers, A., Wight, J., Pardoen, Thomas, Van den Berghe, S., André, Nicolas, Coulombier, N., and Raskin, Jean-Pierre

Published
2022

46. staat van ons klimaat 2021 : Nederlands weer in tijden van klimaatverandering

Author

Leenaers, H., Siegmund, P., Leenaers, H., and Siegmund, P.

Abstract

In deze (eerste) Staat van ons klimaat in 2021 geeft het KNMI een overzicht van (extreem) weer en klimaat in het afgelopen jaar. Het accent ligt daarbij op Nederland, waarbij wordt laten zien hoe en wat hier gebeurt, samenhangt met klimaat(verandering) in Europa en wereldwijd. Voor Nederland wordt een samenvatting gegeven van het gemiddelde weer in 2021 en wordt dat vergeleken met de huidige klimaatnormaal 1991-2020 (het gemiddelde weer in de afgelopen 30 jaar). De belangrijkste extreem-weersituaties in Nederland in 2021 worden beschreven, waaronder uiteraard de hevige neerslag in juli, die leidde tot wateroverlast in Zuid-Limburg. Daarnaast wordt een overzicht van de belangrijkste gevolgen van de wereldwijde opwarming voor Nederland gegeven, zoals zeespiegelstijging, droogte en extreme neerslag.

Published
2022

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