LUCIANO ONDIR FREIRE

LUCIANO ONDIR FREIRE

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A preliminary proposal for a hybrid lattice confinement fusion-fission reactor for mobile nuclear power plants
2022 - FREIRE, LUCIANO O.; ANDRADE, DELVONEI A. de
Scientists detected 2.45-MeV neutrons and in smaller yields 4- and 5-MeV neutrons in deuterated metals under a 2.9-MeV electron beam. Such discovery could allow the use of deuterated metals at temperatures below their melting point to provide nuclear fusion reactions. Such reactions could provide fast neutrons and energy in the form of heat. This work analyzed the results of some experiments to infer the neutron multiplication rate in such environments. It also considered the possible roles that such phenomena could play in a commercial nuclear power reactor under economic and compactness constraints. It seems the best way to promote nuclear fusion is the irradiation of deuterated metals by fast neutrons. This work presents the concept of a hybrid fusion–fission reactor using fissile or fertile fuel to generate heat and fast neutrons along deuterated metals providing excess neutrons (reactivity boost). Additionally, deuterated metals also may have a role in neutron moderation requiring less volume than other moderators (water or graphite). Such a reactor, given its reactivity boost, may burn radioactive residuals (transmutation) at affordable costs while generating power. Alternatively, this hybrid fusion–fission concept could also breed fissile fuel from fertile isotopes using natural uranium as seed.
Clean and safe nuclear power
2021 - FREIRE, LUCIANO O.; ANDRADE, DELVONEI A. de
New research developments suggest that nuclear reactors using fusion may enter the market sooner than imagined even for mobile applications, like merchant ship propulsion and remote power generation. This article aims at pointing such developments and how they could affect nuclear fusion. The method is enumerating the main nuclear reactors concepts, identifying new technological or theoretical developments, and analysing how new recombination could affect feasibility of nuclear fusion. New technologies or experimental results do not always work the way people imagine, being better or worse for intended effects or even bringing completely unforeseen effects. Results point the following designs could be successful, in descending order of potential: aneutronic nuclear reactions using lattice confinement, hybrid fission-lattice confinement fusion, aneutronic nuclear reactions using inertial along magnetic confinement, and fission reactions.
Some facts about nuclear forces and evidence of their range being longer than people believe
2021 - FREIRE, LUCIANO O.; ANDRADE, DELVONEI A. de
Nuclear forces are believed to have ranges around 2 fermi and beyond that range, only electrostatic force is relevant. Before trying to make theories about the phenomena of nuclear reactions observed in solids, it is important to revise critically the existing experimental literature and nuclear theory to check if current models are coherent and if they could explain the observed phenomena. The first step is to check the current nuclear models, the second is to analyse the neutron cross-section data, the third is to discuss coherence between empirical data and models, the fourth is to identify the order of magnitude of nuclear forces range, the fifth is to revise the full height of Coulomb barrier. It was found one isotope (Gadolinium-157) that can attract a thermal neutron at least at 2781 fermi and repulses neutrons at 179 Fermi. It was also found that the plane projection of volumes where neutrons are directly captured is distinct of the projection of the volume where neutrons are scattered for most isotopes. But Kryptonium, Ruthenium, Xenonium, Iridium, and Mercury elements seem having their scattering volumes covered by the absorption volumes, or not having a scattering volume at all. Ca-44, Ca-48, Ni-64, Se-74, Te-123, Dy-162, Hf-177 and W-186 isotopes seem having a partial screening of their scattering volume by the absorption volume. Resonance capture volumes seem to be independent of direct capture volumes and have interface with scattering volume. Three facts suggest absorption volumes are consequence of nucleons arrangement, assuming an FCC nucleus model. The first is that a single additional neutron may change the order of magnitude of absorption radius (like He-3 to He-4). Second, excited states also change absorption cross-sections, like Na-23 whose first excited state increases absorption cross-section and Cl-37 whose first excited state decreases absorption cross-section. Third, neutron capture resonance depends on existence of an excited state of the compound nucleus (target nucleus plus the neutron) with energy larger than this neutron binding energy. In other words, to have a resonance, the target nucleus needs to have two places available for a neutron, and the energetic distance between them needs to be larger than a minimum (the very neutron binding energy). Compared to Coulomb forces, the nuclear forces attracting neutrons are weak, about 6 orders of magnitude smaller than electrostatic repulsion at mean thermal neutron capture radius.
A survey on the evolution of yearly works on Pd-D, Ti-D and Ni-H systems within cold fusion field
2021 - FREIRE, LUCIANO O.; ANDRADE, DELVONEI A. de
More than 30 years have been passed since Stanley and Pons press conference announcing the discovery of “Cold Fusion”. This work aims at presenting a general view of the evolution of experimental works in the various sub-fields, like Pd-D, Ti-D, Ni-H systems. For each subfield, this work presents the yearly number of successful and unsuccessful works published in conferences or journals. For Pd-D systems, since 1989, the number of positive results (finding some nuclear reactions) is superior to negative results but there is a trend of reduction of yearly works. Ti-D systems follow the same tendency. Ni-H systems, on the other hand, present a rising tendency besides having a higher ratio of successful/unsuccessful experiments. Perhaps the smaller cost of materials and easier replication is being decisive for new research groups starting in the field, besides enterprises starting advertisement of products based on the Ni-H system.
A hypothesis of kinetics and dynamic control of nuclear reactions in solids
2021 - FREIRE, LUCIANO O.; ANDRADE, DELVONEI A. de
Several authors suggested that background noise could influence nuclear reactions in solids, resulting in neutrons or excess heat. Literature shows that repeatability is improving, but the control over the intensity remains out of reach. This work aims at identifying possible causes for intensity variations and proposing solutions to improve controllability. The first step is to search in literature the characteristics of nuclear reactions in solids: input, output, controlling factors and enabling means. The second step is, from solid experimental facts, draw solid conclusions. The third step is developing some assumptions about the phenomenon. For each controlling factor, verify the feasibility of implementation in a heat exchanger with high surface over volume ratio. Finally, present some alternatives of architectures to improve reactions intensity control. A solid conclusion is hot spots come from aneutronic nuclear chain reactions, meaning each energetic charged particle causes the appearance of more than one new charged particle (effective multiplication factor keff>1). Another conclusion is background neutron radiation starts chain reactions and it causes excess heat intensity variations. An assumption is a local keff>1 causes micro explosions terminating the localized reactions because heat propagates faster than the particle population, resulting in low average keff. Therefore, nanoparticles or working temperatures near melting point reduce local keff allowing slow enhancement of particle population up to a level proportional to the background neutrons. A suggestion is to shield the reactors using moderators with neutron absorbers to avoid undesirable power excursions and add a voltage-controlled neutron source to control the excess heat because of the penetrating nature of neutron radiation. Magnetic or electric fields could also help the enhancement of excess heat.
RANS-based CFD calculation for pressure drop and mass flow rate distribution in an MTR fuel assembly
2021 - SCURO, N.L.; ANGELO, G.; ANGELO, E.; UMBEHAUN, P.E.; TORRES, W.M.; SANTOS, P.H.G.; FREIRE, L.O.; ANDRADE, D.A.
This work presents a Reynolds-averaged Navier Stokes–based computational fluid dynamics methodology for the calculation of pressure drop and mass flow rate distribution in a material test reactor flat-plate-type standard fuel assembly (SFA) of the IEA-R1 Brazilian research reactor to predict future improvements in newer SFA designs. The results improve the understanding of the origin of fuel plate oxidation due to high temperatures, and consequently, due to the internal flow dynamics. All numerical analyses were performed with the ANSYS-CFX® commercial code. The observed results show that the movement pin decreases the central channel mass flow due to the length of the vortex at the inlet region. However, the outlet nozzle showed greater general influence in the flow dynamics. It should have a more gradual cross-section transition being away from the fuel plates or a squarer-shaped design to get a more homogeneous mass flow distribution. Optimizing both regions could lead to a better cooling condition. The validation of the IEA-R1 numerical methodology was made by comparing the McMaster University’s dummy model experiment with a numerical model that uses the same numerical methodology. The experimental data were obtained with laser Doppler velocimetry, and the comparison showed good agreement for both pressure drop and mass flow rate distribution using the Standard k-ω turbulence model.
Preliminary survey on cold fusion
2021 - FREIRE, LUCIANO O.; ANDRADE, DELVONEI A. de
Since 1989 the announcement of “cold fusion” by Stanley Pons and Martin Fleishmann, “cold fusion” field has been surrounded by controversy. After three decades, this field is alive and has produced thousands of publications, most in dedicated periodic and conferences. This work aims at checking whether “cold fusion” fits in pathological science traits. For each type of experiment and year, this work counted the distinct research groups results (success or failure). Experimental results from many research groups suggest that nuclear reactions in solids are more complex than fusion (it is not only fusion) and that they need energy triggers like background radiation, meaning chemical configurations alone do not seem to generate nuclear reactions. Some types of experiments present rising trends (the field does not fit in pathological science model) and have potential to bring disruptive technologies. If confirmed, experimental results will require revisions of accepted nuclear models.
On the commercial feasibility of decommissioning a nuclear power plant ship
2021 - S. JUNIOR, ADALBERTO; FREIRE, LUCIANO O.; ANDRADE, DELVONEI A. de
Functional analysis, diversity and defense-in-depth principle applied for instrumentation and control architecture in accordance with U.S.NRC
2021 - SANTOS, CLAUDIO S.; FREIRE, LUCIANO O.; ANDRADE, DELVONEI A. de
Novel technological developments with impacts on perspectives for mobile nuclear power plants
2021 - FREIRE, LUCIANO O.; ANDRADE, DELVONEI A. de
New research developments suggest that nuclear reactors using fusion may enter the market sooner than imagined even for mobile applications, like merchant ship propulsion and remote power generation. This article aims at pointing such developments and how they could affect nuclear fusion. The method is enumerating the main nuclear reactors concepts, identifying new technological or theoretical developments useful to nuclear field, and analysing how new recombination could affect feasibility of nuclear fusion. New technologies or experimental results do not always work the way people imagine, being better or worse for intended effects or even bringing completely unforeseen effects. Results point the following designs could be successful, in descending order of potential: aneutronic nuclear reactions using lattice confinement, aneutronic nuclear reactions using inertial along magnetic confinement, hybrid fission-lattice confinement fusion, and fission reactions.

LUCIANO ONDIR FREIRE

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