F. Clarens - Academia.edu (original) (raw)

Papers by F. Clarens

HAL (Le Centre pour la Communication Scientifique Directe), Sep 12, 2011

Vas Jornadas de …, 2003

... Autores: Paloma Díaz Arocas, José Luis Gascón Murillo, J. Bruno, J. Quiñones, JA Serrano, G. ... more ... Autores: Paloma Díaz Arocas, José Luis Gascón Murillo, J. Bruno, J. Quiñones, JA Serrano, G. Córdoba, José Antonio Suárez G. del Rey, J. de Pablo, Aurora Martínez Ezquerro, Gabriel Piña Lucas, J. Giménez, J. Cobos, I Casas, A. Uriarte, José Antonio Gago Badenas, A ...

Geochimica et Cosmochimica Acta, 1999

The oxidative dissolution of uranium (IV) dioxide has been experimentally investigated as a funct... more The oxidative dissolution of uranium (IV) dioxide has been experimentally investigated as a function of hydrogen carbonate concentration at 4 different temperatures (10, 25, 45, and 60°C) by using a continuous thin-layer flow-through reactor. The experimental results have been interpreted as evidence for a bicarbonate-promoted oxidative dissolution mechanism which can be differentiated in to 3 steps: 1) initial oxidation of the uranium dioxide solid surface; 2

... HAL : in2p3-00068118, version 1. ... LH Johnson, C. Poinssot, JM Cavedon, Z. Andriambololona,... more ... HAL : in2p3-00068118, version 1. ... LH Johnson, C. Poinssot, JM Cavedon, Z. Andriambololona, D. Wegen, B. Grambow 1 , K. Spahiu, M. Kelm, H. Christensen, J. De Pablo, A. Martínez Esparza, J. Bruno, J. Quiñones, K. Lemmens, G. Mayer, C. Jegou, C. Ferry, P. Lovera, A ...

Radiochimica Acta, 2005

SummaryIn this work we studied the effect of external β radiation (The formation of hydrogen pero... more SummaryIn this work we studied the effect of external β radiation (The formation of hydrogen peroxide in solution was observed in the experiments, as was predicted by the MAKSIMA code. When HThe UO

Environmental Science & Technology, 2004

Understanding the formation of alteration phases on the surface of spent nuclear fuel, such as th... more Understanding the formation of alteration phases on the surface of spent nuclear fuel, such as those observed during leaching experiments, is necessary in order to predict the concentration of radionuclides in the near-field of a final repository. Hydrogen peroxide has been identified as one of the oxidants formed by the radiolysis of water in the presence of spent nuclear fuel; especially due to alpha activity. The presence of this species in solution can contribute to the formation of uranium peroxide secondary phases. In this work, we have studied the oxidative dissolution of synthetic UO2 disks in hydrogen peroxide solutions of two different concentrations (5 x 10(-4) and 5 x 10(-6) mol dm(-3)), both at pH 5.8 +/- 0.1. The solid surface evolution of the disks has been followed by means of ex-situ scanning force microscope (SFM) measurements, and uranium concentration in solution has been determined by inductively coupled plasma mass spectrometry. During the first stage of the experiment, SFM images indicate that only UO2 dissolution is occurring. After 142 h, a secondary phase is observed on the surface of the solid at 5 x 10(-4) mol dm(-3) hydrogen peroxide concentration. This secondary phase has been identified by X-ray diffraction as studtite (UO4 x 4H2O). From the analysis of SFM topographic profiles at different elapsed times, a precipitation rate for the studtite has been estimated to be in the range of (8-32) x 10(-10) mol m(-2) s(-1).

En esta investigación se ha desarrollado un sistema compacto para la regeneración de aguas grises... more En esta investigación se ha desarrollado un sistema compacto para la regeneración de aguas grises con el objetivo de obtener agua regenerada con calidad de reutilización. Mediante un prototipo, que combina un tratamiento biológico con la tecnología de ...

MRS Proceedings, 2006

ABSTRACTThis paper focuses on how to extrapolate current knowledge of spent fuel matrix alteratio... more ABSTRACTThis paper focuses on how to extrapolate current knowledge of spent fuel matrix alteration processes from laboratory to repository conditions, i.e., the influence of changes in both the environmental conditions and the range of time scale considered. Therefore, a spent fuel matrix alteration model allowing the alteration rate evolution to be predicted as a function of both the host rock considered and evaluation time scale of interest is described.At present, the model assumes that alteration of the spent fuel will start when the groundwater reaches the solid surface and that only the radiolytic species of the groundwater (oxidants generated by α-radiation of spent fuel) will produce the surface oxidation process and subsequent matrix dissolution; O2, H2O2 and OH· are the species that react with UO2(s) for oxidation of the pellet surface. The dissolution process of the surface sites that are oxidized is modelled in two steps: first, a surface co-ordination of the oxidized la...

International Journal of Greenhouse Gas Control, 2016

Abstract Cradle-to-gate life cycle assessment was used to compare the environmental impact of cap... more Abstract Cradle-to-gate life cycle assessment was used to compare the environmental impact of capturing CO 2 from the flue gases in a subcritical coal power plant by using three technologies, namely, absorption with two types of amine processes (Econamine and Econamine FG+) and CaO looping. The results were benchmarked against the same power plant with no capture unit. The intended application of the study is to evaluate whether CaO looping can be an alternative to conventional chemical absorption by amine-based processes for capturing CO 2 . The inclusion of the CO 2 capture unit showed a net reduction only in those impact categories directly associated with the reduction of CO 2 as flue gas emissions, i.e. climate change, particulate matter and terrestrial acidification. Emissions for the Climate Change category were 0.33, 0.27 and 0.26 kg CO 2 -eq/kWh for the two amine based systems (Econamine and Econamine FG+, respectively) and the CaO looping capture unit, thereby reducing the emissions of the same plant without a capture unit (0.96 kg CO 2 -eq/kWh). Consequently, with the assumptions and system boundaries defined in this study, the CaO looping is a viable alternative to amine-based systems from the environmental point of view. However, taking into account that CaO looping is a process still under development, additional research and process scale-up is necessary to confirm this result.

Cutting-Edge Technology for Carbon Capture, Utilization, and Storage

Geochmica et Cosmochimica Acta