ON THE MODELLING OF TWO-PHASE FLOW IN HORIZONTAL LEGS OF A PWR

Bestion, D.,Serre, G. Korean Nuclear Society 2012 Nuclear Engineering and Technology Vol.44 No.8

This paper aims at presenting the state of the art, the recent progress, and the perspective for the future, in the modelling of two-phase flow in the horizontal legs of a PWR. All phenomena relevant for safety analysis are listed first. The selection of the modelling approach for system codes is then discussed, including the number of fluids or fields, the space and time resolution, and the use of flow regime maps. The classical two-fluid six-equation one-pressure model as it is implemented in the CATHARE code is then presented and its properties are described. It is shown that the axial effects of gravity forces may be correctly taken into account even in the case of change of the cross section area or of the pipe orientation. It is also shown that it can predict both fluvial and torrential flow with a possible hydraulic jump. Since phase stratification plays a dominant role, the Kelvin-Helmholtz instability and the stability of bubbly flow regime are discussed. A transition criterion based on a stability analysis of shallow water waves may be used to predict the Kelvin-Helmholtz instability. Recent experimental data obtained in the METERO test facility are analysed to model the transition from a bubbly to stratified flow regime. Finally, perspectives for further improvement of the modelling are drawn including dynamic modelling of turbulence and interfacial area and multi-field models.

Porous metal–organic-framework nanoscale carriers as a potential platform for drug delivery and imaging

Horcajada, Patricia,Chalati, Tamim,Serre, Christian,Gillet, Brigitte,Sebrie, Catherine,Baati, Tarek,Eubank, Jarrod F.,Heurtaux, Daniela,Clayette, Pascal,Kreuz, Christine,Chang, Jong-San,Hwang, Young K Nature Publishing Group 2010 NATURE MATERIALS Vol.9 No.2

In the domain of health, one important challenge is the efficient delivery of drugs in the body using non-toxic nanocarriers. Most of the existing carrier materials show poor drug loading (usually less than 5 wt% of the transported drug versus the carrier material) and/or rapid release of the proportion of the drug that is simply adsorbed (or anchored) at the external surface of the nanocarrier. In this context, porous hybrid solids, with the ability to tune their structures and porosities for better drug interactions and high loadings, are well suited to serve as nanocarriers for delivery and imaging applications. Here we show that specific non-toxic porous iron(III)-based metal–organic frameworks with engineered cores and surfaces, as well as imaging properties, function as superior nanocarriers for efficient controlled delivery of challenging antitumoural and retroviral drugs (that is, busulfan, azidothymidine triphosphate, doxorubicin or cidofovir) against cancer and AIDS. In addition to their high loadings, they also potentially associate therapeutics and diagnostics, thus opening the way for theranostics, or personalized patient treatments.

Why hybrid porous solids capture greenhouse gases?

Fé,rey, Gé,rard,Serre, Christian,Devic, Thomas,Maurin, Guillaume,Jobic, Hervé,Llewellyn, Philip L.,De Weireld, Guy,Vimont, Alexandre,Daturi, Marco,Chang, Jong-San Royal Society of Chemistry 2011 Chemical Society reviews Vol.40 No.2

<P>Hybrid porous solids, with their tunable structures, their multifunctional properties and their numerous applications, are currently topical, particularly in the domain of adsorption and storage of greenhouse gases. Most of the data reported so far concern the performances of these solids in this domain, particularly in terms of adsorbed amounts of gas but do not explain at the atomic level why and how adsorption and storage occur. From a combination of structural, spectroscopic, thermodynamic experiments and of molecular simulations, this <I>tutorial review</I> proposes answers to these open questions with a special emphasis on CO<SUB>2</SUB> and CH<SUB>4</SUB> storage by some rigid and flexible hybrid porous materials.</P> <P>Graphic Abstract</P><P>Why and how hybrid porous solids capture gases: exploration combining appropriate <I>in situ</I> measurements and molecular simulations. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c0cs00040j'> </P>

MOF-derived carbonaceous materials enriched with nitrogen: Preparation and applications in adsorption and catalysis

Bhadra, Biswa Nath,Vinu, Ajayan,Serre, Christian,Jhung, Sung Hwa Elsevier 2019 Materials today Vol.25 No.-

<P><B>Abstract</B></P> <P>Porous carbons have been considered very important for a long time because of various possible applications. In this review, we summarize the current progress in the field of porous carbons, especially N-enriched carbons, obtained from the carbonization of MOFs with or without additional N-containing compounds. Moreover, metal- or metal oxide-loaded N-doped carbons are also dealt with. Not only the preparation but also the applications in adsorption and catalysis are summarized. More importantly, research ideas or trends will be suggested for further development of these fields. Finally, this study summarizes a number of methods for the preparation of N-enriched carbons (with or without metal or metal oxide) and their efficiencies in various potential applications, including adsorption (liquid-/gas-phase) and organo-/photo-/electro-catalyses, based on their physicochemical properties.</P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

An Adsorbent Performance Indicator as a First Step Evaluation of Novel Sorbents for Gas Separations: Application to Metal–Organic Frameworks

Wiersum, Andrew D.,Chang, Jong-San,Serre, Christian,Llewellyn, Philip L. American Chemical Society 2013 Langmuir Vol.29 No.10

<P>An adsorbent performance indicator (API) is proposed in an effort to initially highlight porous materials of potential interest for PSA separation processes. This expression takes into account working capacities, selectivities, and adsorption energies and additionally uses weighting factors to reflect the specific requirements of a given process. To demonstrate the applicability of the API, we have performed the adsorption of carbon dioxide and methane at room temperature on a number of metal–organic frameworks, a zeolite and a molecular sieve carbon. The API is calculated for two different CO<SUB>2</SUB>/CH<SUB>4</SUB> separation case scenarios: “bulk separation” and “natural gas purification”. This comparison highlights how the API can be more versatile than previously proposed comparison factors for an initial indication of potential adsorbent performance.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/langd5/2013/langd5.2013.29.issue-10/la3044329/production/images/medium/la-2012-044329_0004.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/la3044329'>ACS Electronic Supporting Info</A></P>

Hydrogen Storage in the Giant-Pore Metal–Organic Frameworks MIL-100 and MIL-101

Latroche, Michel,Surblé,, Suzy,Serre, Christian,Mellot-Draznieks, Caroline,Llewellyn, Philip L.,Lee, Jin-Ho,Chang, Jong-San,Jhung, Sung Hwa,Fé,rey, Gé,rard WILEY-VCH Verlag 2006 Angewandte Chemie Vol.45 No.48

<B>Graphic Abstract</B> <P>Large hydrogen-storage capacity at liquid-nitrogen temperature is exhibited by the metal–organic framework MIL-101. In the zeotype architecture of this porous solid (see picture) each intersection of the cages is occupied by a supertetrahedron formed by trimers of chromium octahedra assembled with benzene-1,4-dicarboxylate ligands. <img src='wiley_img/14337851-2006-45-48-ANIE200600105-content.gif' alt='wiley_img/14337851-2006-45-48-ANIE200600105-content'> </P>

Porous Chromium Terephthalate MIL-101 with Coordinatively Unsaturated Sites: Surface Functionalization, Encapsulation, Sorption and Catalysis

Hong, Do-Young,Hwang, Young Kyu,Serre, Christian,Fé,rey, Gé,rard,Chang, Jong-San WILEY-VCH Verlag 2009 Advanced Functional Materials Vol.19 No.10

<B>Graphic Abstract</B> <P>Recent ideas concerning site-selective functionalization of chromium terephtha-late MIL-101 are discussed, focusing on the utilization of unsaturated Cr(III) sites (see image). Recent advances in synthesis, selective surface functionalization, outstanding sorption properties, encapsulation of nanoobjects, and catalytic applications in MIL-101 are also discussed. <img src='wiley_img/1616301X-2009-19-10-ADFM200801130-content.gif' alt='wiley_img/1616301X-2009-19-10-ADFM200801130-content'> </P>

Stable polyoxometalate insertion within the mesoporous metal organic framework MIL-100(Fe)

Canioni, Romain,Roch-Marchal, Catherine,Sé,cheresse, Francis,Horcajada, Patricia,Serre, Christian,Hardi-Dan, Menaschi,Fé,rey, Gé,rard,Grenè,che, Jean-Marc,Lefebvre, Fré,d Royal Society of Chemistry 2011 Journal of materials chemistry Vol.21 No.4

<P>Successful encapsulation of polyoxometalate (POM) within the framework of a mesoporous iron trimesate MIL-100(Fe) sample has been achieved by direct hydrothermal synthesis in the absence of fluorine. XRPD, <SUP>31</SUP>P MAS NMR, IR, EELS, TEM and <SUP>57</SUP>Fe Mössbauer spectrometry corroborate the insertion of POM within the cavities of the MOF. The experimental Mo/Fe ratio is 0.95, in agreement with the maximum theoretical amount of POM loaded within the pores of MIL-100(Fe), based on steric hindrance considerations. The POM-MIL-100(Fe) sample exhibits a pore volume of 0.373 cm<SUP>3</SUP> g<SUP>−1</SUP> and a BET surface area close to 1000 m<SUP>2</SUP> g<SUP>−1</SUP>, indicating that small gas molecules can easily diffuse inside the cavities despite the presence of heavy phosphomolybdates. These latter contribute to the decrease in the overall surface area, due to the increase in molar weight, by 65%. Moreover, the resulting Keggin containing MIL-100(Fe) solid is stable in aqueous solution with no POM leaching even after more than 2 months. In addition, no exchange of the Keggin anions by tetrabutylammonium perchlorate in organic media has been observed.</P> <P>Graphic Abstract</P><P>Keggin 12-phosphomolybdates were encapsulated into mesoporous iron trimesate MIL-100(Fe) by direct synthesis, maintaining gas accessibility and avoiding POM leaching. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c0jm02381g'> </P>

Status of the Astrid Core at the end of the Pre-Conceptual Design Phase 1

MS. CHENAUD,N. Devictor,G. Mignot,F. Varaine,C. Venard,L. Martin,M. Phelip,D. Lorenzo,F. Serre,F. Bertrand,N. Alpy,M. Le Flem,P. Gavoille,R. Lavastre,P. Richard,D. Verrier,D.Schmitt 한국원자력학회 2013 Nuclear Engineering and Technology Vol.45 No.6

Within the framework of the ASTRID project, core design studies are being conducted by the CEA with support from AREVA and EDF. The pre-conceptual design studies are being conducted in accordance with the GEN IV reactor objectives, particularly in terms of improving safety. This involves limiting the consequences of 1) a hypothetical control rod withdrawal accident (by minimizing the core reactivity loss during the irradiation cycle), and 2) an hypothetical loss-of-flow accident (by reducing the sodium void worth). Two types of cores are being studied for the ASTRID project. The first is based on a ‘large pin/small spacing wire’ concept derived from the SFR V2b, while the other is based on an innovative CFV design. A distinctive feature of the CFV core is its negative sodium void worth. In 2011, the evaluation of a preliminary version (v1) of this CFV core for ASTRID underlined its potential capacity to improve the prevention of severe accidents. An improved version of the ASTRID CFV core (v2) was proposed in 2012 to comply with all the control rod withdrawal criteria, while increasing safety margins for all unprotected-loss-of-flow (ULOF) transients and improving the general design. This paper describes the CFV v2 design options and reports on the progress of the studies at the end of pre-conceptual design phase 1 concerning: - Core performance, - Intrinsic behavior during unprotected transients, - Simulation of severe accident scenarios, - Qualification requirements. The paper also specifies the open options for the materials, sub-assemblies, absorbers, and core monitoring that will continue to be studied during the conceptual design phase. Within the framework of the ASTRID project, core design studies are being conducted by the CEA with support fromAREVA and EDF. The pre-conceptual design studies are being conducted in accordance with the GEN IV reactor objectives,particularly in terms of improving safety. This involves limiting the consequences of 1) a hypothetical control rod withdrawalaccident (by minimizing the core reactivity loss during the irradiation cycle), and 2) an hypothetical loss-of-flow accident (byreducing the sodium void worth). Two types of cores are being studied for the ASTRID project. The first is based on a ‘large pin/small spacing wire’concept derived from the SFR V2b, while the other is based on an innovative CFV design. A distinctive feature of the CFVcore is its negative sodium void worth. In 2011, the evaluation of a preliminary version (v1) of this CFV core for ASTRID underlined its potential capacity toimprove the prevention of severe accidents. An improved version of the ASTRID CFV core (v2) was proposed in 2012 to comply with all the control rod withdrawalcriteria, while increasing safety margins for all unprotected-loss-of-flow (ULOF) transients and improving the general design. This paper describes the CFV v2 design options and reports on the progress of the studies at the end of pre-conceptualdesign phase 1 concerning:- Core performance,- Intrinsic behavior during unprotected transients,- Simulation of severe accident scenarios,- Qualification requirements. The paper also specifies the open options for the materials, sub-assemblies, absorbers, and core monitoring that willcontinue to be studied during the conceptual design phase.

STATUS OF THE ASTRID CORE AT THE END OF THE PRE-CONCEPTUAL DESIGN PHASE 1

Chenaud, Ms.,Devictor, N.,Mignot, G.,Varaine, F.,Venard, C.,Martin, L.,Phelip, M.,Lorenzo, D.,Serre, F.,Bertrand, F.,Alpy, N.,Le Flem, M.,Gavoille, P.,Lavastre, R.,Richard, P.,Verrier, D.,Schmitt, D. Korean Nuclear Society 2013 Nuclear Engineering and Technology Vol.45 No.6

Within the framework of the ASTRID project, core design studies are being conducted by the CEA with support from AREVA and EDF. The pre-conceptual design studies are being conducted in accordance with the GEN IV reactor objectives, particularly in terms of improving safety. This involves limiting the consequences of 1) a hypothetical control rod withdrawal accident (by minimizing the core reactivity loss during the irradiation cycle), and 2) an hypothetical loss-of-flow accident (by reducing the sodium void worth). Two types of cores are being studied for the ASTRID project. The first is based on a 'large pin/small spacing wire' concept derived from the SFR V2b, while the other is based on an innovative CFV design. A distinctive feature of the CFV core is its negative sodium void worth. In 2011, the evaluation of a preliminary version (v1) of this CFV core for ASTRID underlined its potential capacity to improve the prevention of severe accidents. An improved version of the ASTRID CFV core (v2) was proposed in 2012 to comply with all the control rod withdrawal criteria, while increasing safety margins for all unprotected-loss-of-flow (ULOF) transients and improving the general design. This paper describes the CFV v2 design options and reports on the progress of the studies at the end of pre-conceptual design phase 1 concerning: - Core performance, - Intrinsic behavior during unprotected transients, - Simulation of severe accident scenarios, - Qualification requirements. The paper also specifies the open options for the materials, sub-assemblies, absorbers, and core monitoring that will continue to be studied during the conceptual design phase.