906 research outputs found

    EURISOL-DS Multi-MW Target Neutronic Calculations for the Baseline Configuration of the Multi-MW Target

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    This document summarises the study performed within the Task #2 of the European Isotope Separation On-Line Radioactive Ion Beam Facility Design Study (EURISOL DS) [1] to design the Multi-MW proton-to-neutron converter. A preliminary study [2] was carried out in order to understand the nature of the interactions taking place in the proton-to-neutron converter and their impact on the design of the facility. Namely, the target dimensions and material composition, type of incident particle, its energy and the beam profile were analysed in the aforementioned technical note, and their optimum values were suggested in the conclusions. The present work is based on the results of the previous study and uses the same methodology, namely Monte Carlo simulations with FLUKA [3]. This note describes the performance of a Hg target design and addresses more detailed issues, such as the composition of the fission target and use of a neutron reflector. It also attempts to integrate those components together and estimate the whole performance in terms of number of fissions, isotopic yields and power densities. The results of these calculations show the feasibility of this Multi-MW target design and the possibility of achieving the aimed fission rates with a reduced fission target. The assembly has been characterised in terms of neutronics and power densities, both key factors in the technical design, due to the high isotopic yields aimed and the large power densities foreseen

    Baseline Design of a Solid Neutron Converter Driven by 160 MeV Protons

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    The European Isotope Separation On-Line Radioactive Ion Beam Facility Design Study (EURISOL DS) aims at the design of several spallation and fission targets for the production of radioactive isotopes. Namely, direct targets, where high-energy protons interact directly with the fission targets, as well as the design of a Multi-MW proton-to-neutron converter coupled with a fission target. For the later, several options have been proposed, including the use of a relatively low energy (in the hundreds of MeV) high intensity proton beam. In this scope, the neutronic characteristics of a tantalum n-converter/fission-target system have been established (although not yet optimised) for a reference proton energy of 160 MeV. A set of simulations has been carried out for different design requirements and different characteristics of the proton beam. An extensive comparison of the main physical parameters has also been carried out, in order to allow the optimal engineering design of the whole target station

    EURISOL-DS Multi-MW Target Comparative Neutronic Performance of the Baseline Configuration vs. the Hg-Jet Option

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    This technical report summarises the comparative study between several design options for the Multi-MW target station performed within Task #2 of the European Isotope Separation On-Line Radioactive Ion Beam Facility Design Study (EURISOL DS) [1]. Previous analyses were carried out, using the Monte Carlo code FLUKA [2], to determine optimal values for relevant parameters in the target design [3] and to analyse a preliminary Multi-MW target assembly configuration [4]. The second report showed that the aimed fission rates, i.e. ~1015 fissions/s, could be achieved with such a configuration. Nevertheless, a preliminary study of the target assembly integration [5] suggested reducing some of the dimensions. Moreover, the yields of specific isotopes have yet to be assessed and compared to other target configurations. This note presents a detailed comparison of the baseline configuration and the Hg-jet option, in terms of primary and neutron distribution, power densities and fission product yields. A scaled-down version of the baseline configuration (i.e. reduced radius and length), is proposed and compared with the other designs. The results confirm the feasibility of the reduced target configuration, while obtaining fission product yields comparable to those of the Hg-jet layout, without the technical problems of the latter. Significant fission rates may be obtained with 4 MW of beam power and few one-litre UnatC3 targets. Moreover, the energy deposited in the liquid metal may be evacuated with reasonable flow rates

    Modifications to the SPS LSS6 Septa for LHC and the SPS Septa Diluters

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    The Large Hadron Collider required the modification of the existing extraction channel in the long straight section (LSS) 6 of the CERN Super Proton Synchrotron (SPS), including the suppression of the electrostatic wire septa. The newly set up fast extraction will be used to transfer protons at 450 GeV/c as well as ions via the 2.9 km long transfer line TI 2 to Ring 1 of the LHC. The girder of the existing SPS DC septa was modified to accommodate a new septum protection element. Changes were also applied to the septum diluter in the fast extraction channel in LSS4, leading to the other LHC ring and the CNGS facility. The requirements and the layout of the new LSS6 extraction channel will be described including a discussion of the design and performance of the installed septum diluters

    Energy Deposition in Adjacent LHC Superconducting Magnets from Beam Loss at LHC Transfer Line Collimators

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    Injection intensities for the LHC are over an order of magnitude above the damage threshold. The collimation system in the two transfer lines is designed to dilute the beam sufficiently to avoid damage in case of accidental beam loss or mis-steered beam. To maximise the protection for the LHC most of the collimators are located in the last 300 m upstream of the injection point where the transfer lines approach the LHC machine. To study the issue of possible quenches following beam loss at the collimators part of the collimation section in one of the lines, TI 8, together with the adjacent part of the LHC has been modeled in FLUKA. The simulated energy deposition in the LHC for worst-case accidental losses and as well as for losses expected during a normal filling is presented

    Morbi-Mortalité des Contusions Abdominales : La Face Visible de L’iceberg

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    Objectif : rapporter la morbimortalité des contusions abdominales (CA) à l’hôpital national de Niamey. Patients et méthode : il s’agissait d’une étude rétrospective, descriptive et analytique sur 4 ans incluant les patients pris en charge pour CA à l’hôpital national de Niamey. Les variables étudiées étaient le sexe, l’âge, le mode de traitement, les lésions abdominales, les lésions associées, la morbidité et la mortalité. Résultats : l’étude incluait 137 patients, soit 1,6% des urgences abdominales. Il s’agissait de 116 hommes et de 27 femmes avec un sex ratio de 5,52. L’âge moyen des patients était de 22,09 ±12,3 ans. Le délai moyen d’admission était de 18,4 ±26,3 heures. Les accidents de la voie publique représentaient 49,64% des circonstances de survenue du traumatisme. La CA était isolée chez 75,2% des patients et associée à une lésion extra-abdominale chez 24,8% des patients. Cette association lésionnelle réalisait un polytraumatisme chez 18,9% des patients. Les lésions abdominales étaient dominées par les lésions spléniques survenues chez 38,6% des patients, suivies par les lésions de l’intestin grêle chez 12,4% des patients. Une complication était survenue chez 10,9% des patients et 6,5% des patients étaient décédés à l’hôpital. La survenue de complications était influencée par le délai d’admission et la survenue d’une péritonite (p=0,002). L’hémorragie était la principale cause de décès. Conclusion : les CA constituent un traumatisme de l’adulte jeune de sexe masculin. La morbimortalité des CA n’est peut être que ‘’la face visible de l’iceberg’’. Objective : to report the morbidity and the mortality of the blunt abdominal trauma (BAT) at the national hospital of Niamey. Patients and method: it was a retrospective, descriptive and analytical study over 4 years including patients managed for BAT at the national hospital of Niamey. The variables analyzed were the age, sex, treatment, abdominal organs injury, associated injury, morbidity and mortality. Results: the study included 137 patients, whether 1.6% of abdominal emergencies. They were 116 men and 27 women, with a sex ratio of 5.52. The average age was 22.09[±12.3] years old. The average intake time was 18.43[±26.3] hours. Car crashes accounted for 49.64% of the circumstances of the trauma. The BAT was isolated in 75.2% of patients and associated to a (34) extra-abdominal trauma in 24.8% of patients. This lesional association achieved polytrauma in 18.9% of patients. The most abdominal organ injured was spleen in 38.6% of patients followed by small intestine in 12.4% of patients. The morbidity rate was 10.9% and the intrahospital mortality rate was 6.5%. The occurrence of morbidity was influenced by the intake time and the occurrence of peritonitis (p=0.002). Hemorrhage was the leading cause of death. Conclusion: BAT are most frequent in young male adults at national hospital of Niamey. The morbimortality of BAT is perhaps ‘’the visible face of the iceberg’’

    Fast neutron incineration in the energy amplifier as alternative to geologic storage: the case of Spain

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    In previous reports [1][2] we have presented the conceptual design of a fast neutron driven sub-critical device (Energy Amplifier) designed both for energy amplification (production) and for the incineration of unwanted ³waste² from Nuclear Light Water Reactors (LWR). The latter scheme is here applied to the specific case of Spain, where 9 large LWR¹s are presently in operation. It is shown that a cluster of 5 EA¹s is a very effective and realistic solution to the elimination (in 37 years) of the present and foreseen (till 2029) LWR-Waste stockpiles of Spain, but with major improvements over Geologic Storage, since: (1) only a Low Level Waste (LLW) surface repository of reasonable size is ultimately required; (2) the large amount of energy stored in the trans-Uranics is recovered, amounting for each of the 37 years of incineration to a saving of about 8% of the present primary energy demand of Spain (100 MTep/y); (3) the slightly enriched (1.1%) Uranium, unburned by LWR¹s, can be recovered for further use; (4)Trans-Uranic waste is transformed into fissile 233U,whichcanbeusedtomake+20{^233}U, which can be used to make +20% of LWR fuel without isotopic separation and (5) the capital cost of the complete facility, including reprocessing is convincingly lower than the one of the Geologic Storage. The volume of the ultimately Class A LLW can be further reduced by about an order of magnitude transmuting parasitically in the EA¹s into stable nuclear species also the two most offending long-lived isotopes, {^99}Tcand and {^128}I.ThetotalLLWvolumeultimatelyrequired(601000m3)willthenberoughlyabout1. The total LLW volume ultimately required (60¹000 m3) will then be roughly about 1% of the present LLW storage in the USA and comparable to the present capacity of the now operational ³El Cabril² in Spain (50¹000 m{^3}$). We conclude that EA-driven incineration when compared to direct Geological Disposal is environmentally more acceptable and economically more advantageous. Finally, no major technical barriers hinder its realisation

    Transient Thermo-Mechanical Analysis of the TPSG4 Beam Diluter

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    A new extraction channel is being built in the Super Proton Synchrotron (SPS) Long Straight Section 4 (LSS4) to transfer proton beams to the Large Hadron Collider (LHC) and also to the CERN Neutrino to Gran Sasso (CNGS) target. The beam is extracted in a fast mode during a single turn. For this purpose a protection of the MSE copper septum coil, in the form of a beam diluting element placed upstream, will be required to cope with the new failure modes associated with the fast extraction operation. The present analysis focuses on the thermo-mechanical behavior of the proposed TPSG4 diluter element irradiated by a fast extracted beam (up to 4.9 x 10^13 protons per 7.2 mus pulse) from the SPS. The deposited energy densities, estimated from primary and secondary particle simulations using the high-energy particle transport code FLUKA, were converted to internal heat generation rates taken as a thermal load input for the finite-element engineering analyses code ANSYS. According to the time dependence of the extracted beam, the transient solutions were obtained for coupled heat transfer, structural deformation, and shock wave problems. The results are given for the space distribution and the time evolution of temperatures and stresses in the most critical parts of the TPSG4 beam diluting element followed by the MSE copper septum coil. In the worst case of impact of the full LHC ultimate beam, the maximum temperatures remain safely below the melting point. However, the maximum equivalent stresses may slightly exceed the elastic limit in the aluminium section of the diluter. Also, the predicted maximum temperature rise in the MSE septum coil exceeds the design value
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