1,721,422 research outputs found
A possible approach to 14 MeV neutron moderation: A preliminary study case
No full textDeuterium-Tritium (D-T) interactions produce almost monochromatic neutrons with about 14 MeV energy. These neutrons are used in benchmark experiments as well as for neutron cross sections assessment in fusion reactors technology. The possibility to moderate 14 MeV neutrons for purposes beyond fusion is worth to be studied in relation to projects of intense D-T sources. In this preliminary study, carried out using the MCNP Monte Carlo code, the moderation of 14 MeV neutrons is approached foreseeing the use of combination of metallic materials as pre-moderator and reflectors coupled to standard water moderators. © 2017 Elsevier Lt
Nuclear analysis of the ITER Cryopump Ports
No full textThe ITER machine will be equipped with 6 torus Cryopumps (TCP) that are positioned in their housings (TCPH) and integrated into the cryostat walls at B1 level in the port cells. A comprehensive nuclear analysis of the Cryopump Ports #4 and #12 has been carried out by means of the MCNP-5 Monte Carlo code in a full 3-D geometry, providing guidelines for the design of the embedded components. Radiation transport calculations have been performed in order to determine the radiation field inside the Lower Ports, up the Port Cell: 3-D neutrons and gamma maps have been provided in order to evaluate the shielding effectiveness of the TCPHs. Nuclear heating induced by neutron and photons have been estimated on the TCP and TCPH to assess the nuclear loads during plasma operations. The shutdown dose rate in the maintenance area of the Lower Ports has been assessed with the Advanced D1S method to verify the design limits. © 2015 Elsevier B.V. All rights reserved
From neutron Compton profiles to momentum distribution: Assessment of direct numerical determination
Full text linkInelastic neutron scattering at high momentum transfers, in the neutron
Compton scattering regime, provides an access to the neutron Compton
profiles, the analogous of Compton profiles in X-ray scattering. The
line shape analysis of the neutron Compton profiles is usually carried
out making use of multiparametric nonlinear fitting, garnering detailed
information about the momentum distribution of the target atoms. This
paper presents the proposal to directly determine numerically the
momentum distribution from the profiles, thus eliminating the possible
instabilities present in multiparametric fitting. A comparison with
Monte Carlo simulations and with previous measurements on
polycrystalline ice provides quantitative assessments of the proposed
method. (C) 2012 Elsevier B.V. All rights reserved
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Progress in development of advanced D1S dynamic code for three-dimensional shutdown dose rate calculations
No full textThe Advanced Direct 1-Step (AdD1S) is one of the most validated tools for the evaluation of Shutdown Dose Rate in complex fusion tokamak machines. The present work is built on the experience in analyzing tokamaks using prior versions of the code, where the activation analysis was limited to the first-step reactions. In the light of the neutron irradiation scenarios foreseen for fusion power reactors and the increasing importance of safety requirements, the possibility to treat the multi-step reactions introduced in the present version represents a novel and relevant development in the field. Moreover, a new Python library, PyD1S, has been developed to optimize the MCNP-FISPACT interface and data analysis. In this paper, the recent developments and the first applications are presented
, Pressioni di vapore del sistema etanolo acqua cloruro di calcio da 40 a 95 C. Quaderni dell'Ingegnere Chimico Italiano, 25, N. 9 10 (1989) 2 4. (Supplemento di "La Chimica e L'Industria" dicembre 1989)
No full textNeutronics experiments, radiation detectors and nuclear techniques development in the EU in support of the TBM design for ITER
No full textThe development of high quality nuclear data, radiation detectors and instrumentation techniques for fusion technology applications in Europe is supported by Fusion for Energy (F4E) and conducted in a joint and collaborative effort by several European research associations (ENEA, KIT, JSI, NPI, AGH, and CCFE) joined to form the "Consortium on Nuclear Data Studies/Experiments in Support of TBM Activities". This paper presents the neutronics activities carried out by the Consortium. A selection of available results are presented. Among then a benchmark experiment on a pure copper block to study the Cu cross sections at neutron energies relevant to fusion, the fabrication of prototype neutron detectors able to withstand harsh environment and temperature >200 °C (artificial diamond and self-powered detectors) developed for operating in ITER-TBM as well as measurement of relevant activation and integral gas production cross-sections. The latter measured at neutron energies relevant to IFMIF (>14 MeV) and the development of innovative experimental techniques for tritium measurement in TBM. © 2015 Elsevier B.V. All rights reserved
Pre-analysis of the copper neutronics benchmark experiment for nuclear data validation
No full textA new benchmark experiment on pure copper assembly is presently underway at the Frascati Neutron Generator (FNG) aimed at testing and validating the recent nuclear data libraries for fusion applications under 14 MeV neutrons irradiation. The Copper block has been designed on the basis of the pre-analysis presented in this work, performed with the MCNP5 Monte Carlo code, using JEFF 3.1.1 nuclear data library for transport and IRDF2002 for activation foils reaction rates. The pre-analysis has been performed in order to define suitable dimensions of the copper block and to optimize the experimental set-up for the measurements. This includes the definition of the detectors positions and the irradiation conditions required to get measurable activities for the activation foils. Furthermore, the design has been optimized to reduce the effect of the background due to the neutrons back-scattered from the FNG bunker walls. A 60 cm × 70 cm × 60 cm copper block, without any shield, results suitable for conducting a "clean" benchmark experiment. © 2015 Elsevier B.V. All rights reserved
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