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[en] This thesis work deals with the coupling mechanisms between an electron, water molecules or protic species (hydronium ion, hydroxyl radical). Two complementary studies have been carry out in pure aqueous phases. The first one is concerned with the structural aspect of the hydrated electron which is studied via a semi-quantum approach Splitting Operator Method. The results indicates the importance of the second hydration shell in the localisation of an electron at 77 and 300 Kelvin. The second part of this work relates to the dynamic of the primary processes in light or heavy water at room temperature: the ion-molecule reaction, radical pair formation, geminate recombination of the hydrated electron with the hydronium ion and the hydroxyl radical. The dynamic of these reactions is studied by time resolved absorption spectroscopy from the near infrared to the near ultraviolet with a few tens femto-seconds temporal precision. The analysis of the primary processes takes into account the protic properties of water molecules. (author)
[fr]Les travaux de cette these traitent des mecanismes de couplage entre un electron, des molecules d'eau ou des especes protiques (ion hydronium, radical hydroxyle). Deux etudes complementaires ont ete menees dans des phases aqueuses pures. La premiere etude, a caractere structural, correspond a une approche semi-quantique d'un etat totalement hydrate de l'electron. Les resultats obtenus montrent l'importance de la seconde sphere d'hydratation dans la localisation de cet l'electron a 77 et 300 Kelvin. La seconde partie de ce travail se refere a l'etude de la dynamique des mecanismes reactionnels primaires dans l'eau et l'eau lourde a temperature ambiante: la reaction ion-molecule, la formation de paires radicalaires, la recombinaison geminee de l'electron avec le proton hydrate et le radical hydroxyle. La dynamique de ces reactions est etudiee par spectroscopie d'absorption, du proche ultra-violet au proche infrarouge, resolue en temps a l'echelle de quelques dizaines de femtosecondes. L'analyse de ces processus primaires integre le caractere protique des molecules d'eau. (auteur)
[en] This report is to reflect the two complementary aspects of studies and research on the management of radioactive waste and materials. The first chapter addresses partitioning and transmutation (inventory and prospects, implementation methodologies for fast neutron reactors, partitioning technique, transmutation technique with its tools and its experimentations like Astrid, the transmutation of minor actinides, the benefit of Americium transmutation, the scenarios for the deployment of sodium-cooled fast-neutron reactors in the French nuclear power fleet, alternatives to sodium-cooled reactors like gas-cooled, molten salt reactors). The second part addresses the storage and disposal of long-lived high-level (LLHL) and long-lived intermediate-level (LLIL) waste in the Cigeo project: geological knowledge of the zones of interest, studies performed in underground and surface laboratories, research programme, digital simulation capabilities, conduct of the draft phase, project design, necessary flexibility of Cigeo, cost, socio-economic impact. The chapter 3 briefly addresses the management of long-lived low-level (LLLL) waste. Consistent with its mission, the National Assessment Board continues to observe the overall international situation. The main elements are reported in Chapter 4. These elements deal with: options in the management of various wastes, international legal context, research laboratories and underground disposal sites, sources of fast-spectrum irradiation, main international initiatives on Accelerator Driven Systems (ADS), new technologies for partitioning-transmutation
[en] France is aiming to reduce the share of nuclear power in the country's electricity mix, and increase the share of wind and solar power. However, given the intermittency of these renewable energy sources, massive storage systems are required when their share exceeds a certain threshold. That generates additional costs on top of the subsidies already granted to these energies. This article attempts to quantify that additional cost, which varies between 6.3 Euros and 31.6 billion Euros depending on various scenarios. In fact, the cost of renewables storage varies according to our calculations between 108.3 Euros and 251.4 Euros per MWh. That additional cost could be reduced if storage yields were improved. One of the lessons to be drawn from this analysis is that it would be preferable to finance R and D in storage technologies rather than using costly feed-in tariffs or feed-in premiums to finance an increase in renewables. The greatest challenge lies with respect to inter-seasonal storage rather than very short-term battery-based storage. The prospects for power-to-gas and gas-to-power are also promising, but have yet to be proven in practice. (authors)
[en] By force of circumstance, thoroughgoing changes are under way in the ways we consume and produce energy. R and D must respond to these changes by making technological innovations and proposing solutions that are safe, competitive, economic with regard to natural resources and respectful of the environment. The French Commissariat a l'energie Atomique actor (CEA) has a leading role to play
[en] The published work on H bond dynamics mainly refers to diluted solutions HDO/D2O rather than to normal water. The reasons for this choice are both theoretical and experimental. Mechanical isolation of the OH vibrator eliminating the resonant energy transfer makes it a better probe of the local H bond network, while the dilution in heavy water reduces the infrared absorption, which permits the use of thicker experimental cells. The isotopic substitution does not alter crucially the nature of the problem. The length r of an OH . . . O group is statistically distributed over a large interval comprised between 2.7 and 3.2 A with a mean value r0 = 2.86 A. Liquid water may thus be viewed as a mixture of hydrogen bonds of different length. Two important characteristics of hydrogen bonding must be mentioned. (i) The OH stretching vibrations are strongly affected by this interaction. The shorter the length r of the hydrogen bond, the strongest the H bond link and the lower is its frequency ω: the covalent OH bond energy is lent to the OH. . .O bond and reinforces the latter. A number of useful relationships between ω and r were published to express this correlation. The one adopted in our previous work is the relationship due to Mikenda. (ii) Not only the OH vibrations, but also the HDO rotations are influenced noticeably by hydrogen bonding. This is due to steric forces that hinder the HDO rotations. As they are stronger in short than in long hydrogen bonds, rotations are slower in the first case than in the second. This effect was only recently discovered, but its existence is hardly to be contested. In the present contribution, we want to revisit the relationship between the frequency of the OH vibrator and the distance OH. . .O.
[en] A non-empirical theory is presented to study the relation between the OH stretching frequency and the OO distance in ultrafast laser spectra of water. Diluted solutions HDO/D2O rather than pure H2O were considered to switch off resonant vibrational interactions between water molecules; the local structure of water as well as the OO distribution functions remain unchanged in this substitution. Only times superior to 100-200fs are considered to avoid perturbations generated by collisions between water molecules. It is then shown that the Novak-Mikenda type relations between the OH stretching frequency and the OO distance largely survive when going from equilibrium to laser perturbed non-equilibrium systems. It is also shown that temporally varying infrared pump-probe profiles of OH stretching bands in HDO/D2O closely parallel the oxygen-oxygen distribution functions of these solutions. Infrared pump-probe spectroscopy can thus replace time-resolved X-ray diffraction in this particular case.
[en] Photo-excited carminic acid and carminic acid-DNA complexes in a buffer solution at pH 7 have been examined using a variety of spectroscopy techniques, that are in particular, the femtosecond resolved fluorescence upconversion and transient absorption spectroscopy. The observation of dual fluorescence emission, one peaks at 470 nm and the other at 570 nm, indicates to an excited-state (S1) intramolecular proton transfer (ESIPT). A detailed analysis of the transient absorption measurements of an aqueous carminic-acid solution at pH 7 yielded four lifetimes for the excited-state (S1): 8, 15, 33 and 46 ps. On the other hand, only two lifetimes, 34 and 47 ps, were observed by fluorescence upconversion spectroscopy because of the detection limitation to the long wavelength edge of the carminic-acid spectrum. The four S1 lifetimes were ascribed to the coexistence of respectively two tautomer (normal and tautomer) forms of carminic acid, in the non-dissociated state (CAH) and in the deprotonated state (CA-). The fluorescence upconversion measurements of carminic acid-DNA complexes exhibited a prolongation of the fluorescence lifetimes. This effect was accepted as evidence for the formation of intercalation complexes between the carminic acid and the DNA. The intercalative binding of the carminic acid to DNA was confirmed by the fluorescence titration experiments resulting to a binding constant of 2 x 105 M-1 that is typical for anthracycline-DNA complexes
[en] According to the provisions of the 2006 law, the long-term management of long-lived high- and intermediate-level waste (LLHLW and LLILW) has three components: its industrial storage, its disposal in geological repositories and the separation-transmutation of long-lived radioactive elements. In addition, the nuclear industry and the dismantling of decommissioned facilities produce waste of lower activity which requires specific management, in particular because of the large quantities produced. This report evaluates the progress of studies and research on these themes. The purpose of the Cigeo project is to build and operate a geological repository for LLHLW and LLILW radioactive waste. This repository should be created at a depth of 500 m in the 130 m-thick Callovo-Oxfordian (COx) argillite formation in Meuse - Haute-Marne. It has benefited from more than twenty years of studies and research carried out by Andra and the scientific community, notably in the underground laboratory at Bure. The models developed to calculate the sizing of underground structures are convincing because of the care taken with the qualification of the thermo-hydro-mechanical (THM) behaviour of the argillite. Continuous improvement of the physico-chemical modelling of the repository has made it possible to refine quantification of water and gas flows both during the operation of Cigeo and after its closure. Andra must now apply these models to finalise plans for Cigeo. Andra must clarify all the criteria used to validate the configuration and sizing of the structures envisaged. Astrid is a technological demonstrator of a fast-neutron reactor (FNR). It will supply electricity while sustainability recycling plutonium from the reprocessing of spent fuel. In accordance with the 2006 law, for which transmutation aimed at reducing the radiotoxicity of long-lived nuclear waste is a fundamental component, Astrid will evaluate the industrial feasibility of the transmutation of minor actinides. Astrid should also establish the conditions for increased plutonium consumption in order to stop production of nuclear electricity without wasting a large stock of plutonium. All basic nuclear facilities must be cleaned-up and dismantled after they are shut down. This procedure sometimes implies recovery of waste that is stored there. R and D to develop the equipment has been conducted for more than a decade and the actual waste recovery operations will continue for at least two decades. These operations continue under normal conditions. The study carried out by the CEA and the producers provides important information concerning the storage of bitumens. Still to be verified, however, is the possibility of a waste package catching fire and the fire spreading to the entire sector. The Board recommends further experiments on this subject. Finally, it is necessary to re-evaluate alternatives to incineration of these bitumens based on updated data. Very low-level waste (VLLW) represents a considerable volume and Andra expects that its Cires repository, even when extended to 900 000 m3, will be full by 2030; a second repository must then be opened. Andra estimates that about half of VLLW has such low activity that it could be placed in simplified repositories. The Board has already recommended ensuring a consistent policy for the management of low-level waste, whether or not it originates from a nuclear industry. It considers that waste management policy should be based solely on toxicity studies. Isolation and containment times with regard to the biosphere must also be defined, taking account of society's expectations. The issues of a release threshold and low doses clearly underlie these questions. All countries using nuclear energy consider that geological disposal of LLHLW-LLILW is the reference solution. The most advanced European countries are Finland, which has begun construction of its granite repository at a depth of 430 m, and Sweden, where the procedures for authorisation to build a granite repository are expected to come to fruition in 2018. In the United States, the procedure for granting authorisation for Yucca Mountain is restarting. Canada is looking for repository sites in geologically well-adapted areas that also benefit from a societal agreement. Accelerator-Driven Systems (ADS) have been proposed as alternatives to fast reactors for the transmutation of actinides. Research continues internationally, principally in the framework of the European Myrrha project, piloted by the Belgian SCK.CEN and included in the ESFRI road map. Most countries with a nuclear industry have already undertaken dismantling operations (reactors, fuel plants, reprocessing plants (etc.). They show that the technologies are available to perform dismantling while observing all the conventional and nuclear safety standards. The methodologies for estimating the costs have been validated.
[en] According to the provisions of the 2006 law, only ultimate waste is intended to be disposed off. Spent fuel elements are excluded as they contain reusable materials. The law provides for the disposal of long-lived high and intermediate level waste (LL-HLW and LL-ILW) from the current fleet in geological repositories, in accordance with the principle of reversibility, and for the study of partitioning-transmutation of actinides found in the spent fuel of nuclear reactors. Nuclear facilities in operation, dismantling of decommissioned nuclear facilities and certain industries produce long-lived low level waste (LL-LLW), very low level waste (VLLW) or waste with augmented natural radioactivity (Tenorm). These types of waste require specific management schemes due to the very large quantities produced. The aim of the Cigeo project is to build and operate a geological repository for LL-HLW and LLILW included in the French industrial programme for waste management (Programme industriel de gestion des dechets - PIGD), which covers all of the waste from the current fleet. This repository must be created at a depth of 500 m in the 130 m-thick Callovo-Oxfordian (COx) argillite formation at the location of the site in the Meuse-Haute Marne. VLL waste is currently stored in a special centre in Morvilliers, the Cires. Authorised storage capacity there is 650,000 m3 and it should be full by 2030. VLL waste storage capacity requirements have been evaluated up to 2080. They are considerable. In addition to extension of storage capacity at the Cires, another high-capacity center should also be opened to cope with the VLL waste from fleet dismantling. The Board encourages research organisations, industrialists and the authorities to continue their studies on innovative methods for the management of dismantling-derived materials also classified as waste, although they contain little or no added radioactivity. It reiterates its recommendation to develop methods for measuring very low levels of radioactivity in large batches of materials, which should be finalised for supporting any innovative VLL waste management strategies. To meet the objectives laid down by the law of 2006, the CEA is developing the Astrid project, an industrial demonstrator of a generation IV fast-neutron reactor. This highly innovative project is an essential step to introducing these reactors to the electricity-generating fleet. Astrid will allow to assess the industrial feasibility of multiple recycling of its own fuel. France, Finland and Sweden are today the three countries in which significant progress has been made in the process to obtain permission to create a deep geological, high-level waste repository. The decision by the Finnish government to issue a building permit for a repository in granite, of an initial capacity of 6,500 tons of spent fuel came in November 2015. Construction, starting from the existing facility in Olkiluoto, is due to begin in 2016. In Sweden, early 2016, the environmental court announced its decision to consider SKB's application for 12,000 tons of spent fuel as admissible for the public hearing, planned early 2017. A significant European effort, in which Belgium plays a leading role, covers ADS (Accelerator Driven Systems) which are facilities proposed as fast-neutron reactors for actinide transmutation. The core of the reactor in an ADS facility is subcritical. External neutron supply is required to maintain the chain reaction, which is an advantage in terms of safety. The neutrons are provided by a high-intensity proton accelerator bombarding a spallation target. The first section of the accelerator (100 MeV, 4 mA) is planned for 2024. The Allegro fast-neutron reactor project with gas coolant was launched in 2002 in the frame of the Generation IV international forum. Until 2009, the CEA invested significant resources, which enabled it to define the initial characteristics of the experimental Allegro reactor.
[en] According to the provisions of the 2006 act, the long-term management of long-lived high-level waste (LLHLW) comprises two related components: separation-transmutation of actinides present in the spent fuel of future nuclear reactors and the geological disposal of long-lived high and intermediate-level (LLHLW and LLILW) waste in accordance with the principle of reversibility. The 2006 act provides for combining research on partitioning and transmutation with studies and research on the new-generation reactors (fast-neutron reactors, FNRs, and accelerator-driven sub-critical reactors, ADS1). In the context of the Astrid program, innovative options for creating an industrial demonstrator of a new-generation sodium-cooled fast-neutron reactor (FNR-Na), with a degree of safety at least equal to that of the EPR and integrating the lessons learned from the Fukushima events, were identified and have given rise to studies and research (S and R) to prepare the Detailed Preliminary Design (DPD). Main features are: a core with a low run-off coefficient that serves to prevent runaway fission reactions in the event of local drainage of the sodium coolant, of a sodium-sodium-nitrogen energy conversion system, thus preventing any contact between the sodium and the water, an in-service accessibility and inspection a design, and an internal core catcher ensuring vessel integrity in the event of a serious accident. The aim of the Cigeo project is to build an LLHLW and LLILW repository, at a depth of 500 m, in the 130 m thick Callovo-Oxfordian (COx) argillite formation, at the location of the Meuse/Haute- Marne site. Assisted by its contractor Gaiya, Andra proposed in 2012, concluding a so-called draft phase, several overall structure design solutions. In November 2013, the Cigeo project entered its basic preliminary design (BPD) phase. A public debate concerning the Cigeo project was held between 15 May and 15 December 2013, under the auspices of the French national public debates commission (CNDP - Commission nationale des debats publics). The conclusions of the public debate were published on 12 February 2014 and Andra presented its new schedule on 5 May 2014: the BPD shall be completed in May 2015, followed by the detailed preliminary design (DPD) to be completed by May 2017, with the building application (BA). The Board notes a 2-year slippage relative to the initial schedule. The preliminary design S and R pertain mainly to optimising the requirements concerning the LLHLW and LLILW cells. The 2006 act stipulates that deep disposal must be implemented in accordance with the principle of reversibility. Different countries interpret this concept in a different manner. Andra has initiated the debate at both the national and international levels. The OECD's Nuclear Energy Agency (NEA) has defined a reversibility scale for geological disposal: level 1 represents interim surface storage; at level 2, packages are placed in a cell; at level 3, the cell is provided with its final sealing system; at level 4, an entire zone of cells is sealed; finally at level 5, the repository is sealed and safety is ensured in a passive manner. To be effective, reversibility assumes retrievability, i.e. the technical and organisational ability to move the waste packages, or to return them to the surface. This implies a degree of flexibility when creating the facilities, taking into consideration scientific and technical breakthroughs and feedback. The international panorama information presented in report no. 7 remains applicable. The Board has conducted an international analysis of reversibility designs. Moreover, it presents the organisation of management and funding, along with the predicted cost of geological disposal facilities in Belgium, Finland and Sweden. Despite the broad range of approaches and regulatory provisions, these countries all apply the 'polluter pays' principle, give priority to safety and provide funding the construction and operation of the facility for approximately one century.