Physicochimie des produits de fission

Responsable : Florent LOUIS
Co-responsable : Laurent GASNOT

L’équipe de recherche résulte des activités de recherche collaborative initiées depuis 2006 entre le PC2A et le Pôle de Sûreté Nucléaire (PSN) de l’Institut de Radioprotection et de Sureté Nucléaire (IRSN) sur des problématiques relatives à la thermodynamique et à la réactivité chimique de produits de fission. La complémentarité et les compétences de l'IRSN et du PC2A ont permis de rendre pérenne cette collaboration pendant les 10 ans du Laboratoire de Recherche Commun IRSN/CNRS/Lille C3R "Cinétique Chimique, Combustion et Réactivité" (2009 - 2019). Les travaux de recherche portent sur des problématiques couvrant un spectre large de la réactivité chimique homogène et hétérogène, concernant à la fois les aspects expérimentaux, la modélisation théorique et la simulation numérique de ces phénomènes complexes.

Quatre thématiques de recherche sont actuellement en cours d'étude :

Thématique 1 : Etude de la chimie de l’iode de la centrale à l’atmosphère
Thématique 2 : Interaction iode gazeux / aérosols de sodium
Thématique 3 : Revolatilisation de dépôts de produits de fission
Thématique 4 : Métrologie des composés iodés gazeux

L’objectif global des recherches conduites est de valider les estimations de rejets de produits radio-contaminants en cas d’accident en intégrant dans les logiciels de simulation, actuels et en cours de développement, l’état de l’art des connaissances qui sont générées dans le cadre de programmes de recherche nationaux ou internationaux.

Dernières publications de l'équipe :

1) Unraveling the Tropospheric Microhydration Processes of Iodous Acid HOIO

2) Box modelling of gas-phase atmospheric iodine chemical reactivity in case of a nuclear accident

3) Microhydration of caesium metaborate: structural and thermochemical properties of CsBO2 + n H2O (n = 1–4) aggregates

4) A theoretical study of the microhydration processes of iodine nitrogen oxides

5) Reactivity of Hydrogen Peroxide with Br and I Atoms

Les personnels :

Enseignant.e.s-chercheur.e.s  : Fèvre-Nollet V. (MCF HDR), Gasnot L. (PR), Lebègue P. (MCF), Louis F. (MCF, HDR), Pauwels J.F. (PREm), Ribaucour M. (MCF, HDR)

Chercheure invitée : Mosbahi H. (Tunisie)

Personnel BIATSS : Taamalli S. (IR, CDD)
Doctorant : Infuso M. (PhLAM/PC2A, bourse I-Site Oversee, 2022* ), Zainab SROUR (2023*)

(* soutenance prévue)

PR : Professeur des Universités ; PREm : Professeur des Universités Emérite ; MCF : Maître.sse de Conférences ; HDR : Habilité.e à Diriger des Recherches ; IR : Ingénieur.e de Recherche ; IE : Ingénieur.e d'Etude ; AI : Assistant.e-Ingénieur ; T : Technicien.ne

Contrats et collaboration en cours

  • PIA MiRE "Mitigation des Rejets à l’Environnement en cas d’accident nucléaire" (ANR-00-RSNR0013-01), 2014-2019
  • PIA Labex CaPPA "Chemical and Physical Properties of the Atmosphere" (ANR-11-LABX-0005-01), 2013-2022
  • Pr. Ivan Cernusak, Comenius University in Bratislava (Slovaquie)
  • Pr. Alfonso Saiz-Lopez, CSIC (Espagne)
  • Pr. Gabriel da Silva, University of Melbourne (Australie)
  • Pr. Minh Tho Nguyen, KU Leuven (Belgique)
  • Dr. Duy Quang Dao, Da Nang University (Vietnam)

Thèse en cours

Modelling studies of the chlorine atmospheric chemistry

 

The importance of gas-phase halogenated compounds (chlorine, bromine, and iodine) in the atmosphere has been established since the 1970s with the discovery of ozone hole over the Antarctic. These gases generate radicals with a broad range of applications for tropospheric and stratospheric chemistry: ozone budget, atmospheric concentrations (OH, NOx, volatile organic compounds), aerosol formation in the marine boundary layer, halogen interactions, climate change.

 

Numerous studies have been already performed with halogen chemistry using global models. Most of them have focused on bromine and iodine, which are more active than chlorine because of the higher chemical stability of HCl by comparison to other HX acids (X = Br, I). In the chemistry-transport models, there are limited numbers of reactions especially dealing with the organic halogenated compounds. To date, the atmospheric gas phase reactivity and gas–aerosol interactions data sets remain incomplete and poorly understood. Quantum chemistry tools will be employed to gain a more profound insight into the observed reactivity trends and predict thermokinetic parameters for the experimental data that are difficult or impossible to obtain. A recent work performed by our group has demonstrated that the addition of the iodinated organic scheme to the atmospheric model strongly influences its chemical speciation (Fortin et al, Atm. Env., 2019, 214, 116838).

 

The objectives of the thesis are the following: (i) update the chlorine reaction mechanism using an exhaustive literature review, (ii) integrate the new reaction mechanism in the atmospheric models, (iii) perform kinetic analysis with a 0D model to establish the major reaction pathways and to identify the lack of data, (iv) complete the status of knowledge by molecular modelling (v) evaluate with the chemistry-transport model MOCAGE the impact of the updated mechanism on stratospheric and tropospheric air composition at the global scale, in particular on the ozone layer..

 

The new obtained data will help and orient the risk management community and government health and policy makers to better protect and serve the public interest.

Doctorante : Zainab SROUR (zainab.srour@univ-lille.fr)

 

Research program linked to the subject : Labex CaPPA

 

Keywords : Chlorine, atmosphere, molecular simulations, 0D/3D modelling

 

Advisors :          (PC2A)  Florent Louis                 florent.louis@univ-lille.fr             Tel : 03 20 33 63 32

                                     Valérie Fèvre-Nollet       valerie.fevre-nollet@univ-lille.fr   Tel : 03 20 43 67 22

                        CNRM (Météo-France/CNRS)      Virginie Marécal            virginie.marecal@meteo.fr         Tel : 05 61 07 93 61

 

Funding : Labex CaPPA with MétéoFrance

Unravelling the atmospheric iodine chemistry using molecular simulations

The goal is to improve the understanding of the heterogeneous reactivity between gaseous iodinated species and aerosols present in the troposphere. To date, these heterogeneous interactions have not been considered in the atmospheric iodine dispersion models in case of a severe nuclear power plant accident. This is worrisome since such heterogeneous reactivity may play a major role in the iodine transport far from their emission sources. The importance of iodine in atmospheric chemistry has been highlighted by recent reviews. However, the atmospheric iodine heterogeneous reactivity studies have focused almost exclusively on determining the uptake coefficient of inorganic iodinated compounds (for example I2, HI, and HOI) by water or ice. Those conditions are not fully relevant for our applications and have to be extended. Furthermore, photo-oxidation of gaseous CH3I and I2 in presence of O3 is known to produce IxOy aerosols, which are measured in the field campaigns. To the best of our knowledge, the influence of aerosols on the iodine photolysis processes in gas phase is not documented. Finally, the field measurements in Arctic and Antarctica pointed out the role of the low temperature in iodine chemistry in gas phase and in the formation of iodine-rich aerosols.

As a result, this thesis will provide a set of reliable kinetic and mechanistic data on iodine (photo)reactivity with atmospheric aerosols in order to improve the relevance and accuracy of iodine chemistry in dispersion models. The work will be based on molecular simulations; systems associating both the main iodinated gaseous species and representative atmospheric aerosols will be carefully selected.

Both molecular iodine (I2) and iodomethane (CH3I) are key iodine compounds of marine and biogenic origin that appears to be of central importance in understanding iodine chemistry in the troposphere. Further, in addition to their atmospheric interest, the reactivity of those compounds has gained much interest in the field of nuclear safety as they are the most probable gaseous iodine species to be released to the troposphere during a severe nuclear power plant accident of the type in Fukushima, Japan. As a result, this work will start on gaseous molecular iodine and iodomethane surface reactivity as a function of key inorganic and organic aerosols classes from the nanometric up to micrometric size. Model primary and secondary aerosols from marine origin will be considered, such as sodium chloride, sulphate, nitrate, and low to high oxidized organic aerosols.

 

Mots clés : Iodine, aerosols, atmosphere, molecular simulations

Programme de recherche en lien avec le sujet : PIA Labex CaPPA

Financement : projet I-Site Oversee

Doctorant : Maxime INFUSO

Direction : Denis DUFLOT / Florent LOUIS

Master 2 en cours

 

Alumni

 

Chercheurs invités : Prof. Ivan CERNUSAK (Comenius University, Bratislava, Slovakia), Prof. Ted S. DIBBLE (State University of New York College of Environmental Sciences and Forestry, Syracuse, USA), Dr. Duy Quand DAO (Da Nang University, Vietnam)

Post-doctorats : Dr. Sonia TAAMALLI, Dr. Dorra KHIRI, Dr. Sarah KHANNICHE, Dr. Katarina SULKOVA, Dr. Michael BADAWI, Dr. Eddy THIRIOT, Dr. Arnaud VILLARD, Dr. Bertrand XERRI

Thèses : Dr. Camille FORTIN, Dr. Ankita JADON, Dr. Dorel OBADA, Dr. Jan SKOVIERA (co-tutelle avec la Slovaquie), Dr.  Faoulat MIRADJI, Dr. Adrien CARTONNET, Dr. Julien TRINCAL, Dr. Emmanuel MATHE, Dr. Romain VANDEPUTTE, Dr. Yathis DELICAT

Stagiaires: Aurélie LOBBESTAEL (L3, Lille, 2020), Mélissa ACHAB (L3, Lille, 2020), Athmane HARCHAOUI (L3, Lille, 2020), Eliott DUBOIS (L3, ENSCM, 2019), Sandra BALLET (M1, Lille, 2019), Alexis DESCAMPS (L3, Lille, 2019), Laureine FERSING (L3, Lille, 2019), Morgane RIVOAL (L3, Lille, 2019), Guillaume LAMARQUE (L3, Lille, 2019), Anastasia ROTARI (L3, Lille, 2018), Geoffrey LEMOINE (L3, Lille, 2018), Cécile LAFONT (M1, ENSCM, 2018), Olivier ROUILLARD (Erasmus, Canada, 2018)