BR102013033620B1 - CYLINDRICAL CELL FUSER ISOTOPIC TRANSMUTER - Google Patents

Abstract

cylindrical fusing cell for isotope transmutation the present invention refers to a cylindrical fusing cell for isotopic transmutation (ccfti), characterized in that it constitutes a cylindrical device where deuterium (d) or tritium (t) ions, which can be generated by radiofrequency (105) in a plasma chamber (4), they are extracted by the plasma electrode (3) and accelerated radially towards a target electrode (1), where d-d, d-t or t-t fusion occurs, generating neutrons; containing cylindrical annular plasma (3) and target (1) electrodes with deposited metal hydrides; cooling system and target insulator with refrigerant fluid (106) contained in an annular volume in contact with the target electrode (1); an annular volume of the neutron moderator (8) of adjustable radius to the desired transmutation spectrum; one or more receptacles (5) of samples distributed in the moderator (8); and cylindrical annular volumes of the neutron reflector (102) and shield (101). ccfti is useful in transmuting nuclides to generate radioisotopes with a short or long half-life, producing radioactive materials and substances of interest in diagnosis and medical therapy; transmute radionuclides with a long half-life into radionuclides with a short half-life or stable, when burning radioactive waste or reducing the activity of unwanted sources; and transmute fissionable nuclides into fissile ones.

Description

[001] The present invention relates to a Cylindrical Isotope Transmuting Fusor Cell (CCFTI), characterized by constituting a compact cylindrical nuclide activator device, where deuterium (d) or tritium (f) ions are radially accelerated towards a target of deposited, electrically charged metal hydrides, where dd, dt or tt fusion reactions generate neutrons; consisting of a cylindrical plasma chamber (4) fed by a plasma generation system, which may be by radio frequency (RF) and, in this case, an internal RF antenna (105); annular cylindrical plasma electrodes (3) and target electrodes (1); a cooling system and target isolator, which circulates a coolant fluid (106) in a cylindrical annular region in external contact with the target electrode (1), a neutron moderator (8) of a cylindrical annular shape with an adjustable radius to the energy level of the target transmutation neutron beam; one or more sample positioning receptacles (5) to be transmuted positioned internal to the moderator (8); and cylindrical annular volumes of the neutron reflector (102), and the shield (101). CHFTI is intended to activate nuclides through neutron transmutations, so that they can, for example, produce neutron-rich, short- or long-lived radioisotopes, producing materials and radioactive substances of interest in diagnosis and medical therapy; transmute long-lived radionuclides into short-lived or stable radionuclides of interest in burning radioactive waste or reducing the activity of unwanted radioactive sources; or convert fissile nuclides from the transmutation of fissionable nuclides.

[002] Currently, radioisotope production technologies by isotopic transmutation occur, essentially, based on four processes: irradiation of fission neutrons in Fission Reactors (RT), producing radioisotopes rich in neutrons; irradiation of accelerated charged particles in Accelerators (AC), such as protons and alpha, generating proton-rich nuclides; photon irradiation, called Photo-Transmutation (FT), emitted from sealed sources or from electron interactions with heavy targets, such as bremsstrahlung- reactions, and, by Radioisotope Generators (GR), through the decay of a “parent” nuclide precursor ” into a “child” where the parent was previously produced by the RT or AC processes. The RT, AC and GR processes require specific apparatus to produce the transmutation.

[003] The documents that present devices that propose to produce radioisotopes by FT, include:

[004] The patent application “Compact neutron generator for medical and commercial isotope production, fission product purification and controlled gamma reaction for direct electric power generation”- US20110268237A1 consists of a neutron generator, apparatus for producing radioisotopes and methods of use and commercial production of neutrons for medicine. It uses the (y,n) reactions to produce neutrons by bombarding beryllium or deuterium with gamma photons. The interactions of these photons in matter produce neutrons, which are multiplied by a fission converter. It is observed that, due to the low production of neutrons of the reaction (y,n), the fissile material must be incorporated into the device to amplify the neutron flux. Thus, the neutron production method established in patent US20110268237 differs significantly from the present patent, which proposes the production of neutrons through d-d, d-t or t-t fusion reactions and does not present a neutron amplifier.

[005] The document “Isotope generator” - US20070160176A1, proposes to produce radioisotopes through the reaction (n,2n) or (y,n). The proponent suggests employing a neutron source that radiates an adjacent container, where samples are exposed to a neutron flux in order to generate isotopes. The reaction (n,2n) takes place in this container and produces the radioisotopes of interest. A limitation of this patent is associated with the decrease in neutron flux due to the coupling of auxiliary systems made up of heavy elements. The reaction in question requires high-energy neutrons and is limited by the low probability of occurrence for most stable nuclides. After production, neutrons lose their energies by elastic collisions (n,n') with light elements; or inelastic, preferably with elements of intermediate atomic number, competing with any other type of nuclear reaction. Reactions (n,2n) are sporadic compared to reactions (n,rT). In this way, the neutron balance becomes precarious by the self-absorption competition reactions in the device itself in reactions (n,n') and (n, y). In this case, it is known that the reactions (n,2n) produce neutron-poor and proton-rich radioisotopes, and, consequently, positron emitters (β+). Furthermore, the reactions (n,2n) have a high energy threshold and low interaction cross sections (or interaction probability) for most nuclides. To achieve significant cross-section values, there is a remote possibility that reactions with tritium can generate neutrons with energies of 14.1 MeV. Furthermore, it is expected that there will be high neutron leakage from the compact device due to the high energy of the neutrons emitted. Another relevant factor is the inherent moderation of the incorporated materials, which reduces the energy of the neutrons and thus, hinders the occurrence of reactions (n,2n). The use of tritium characterizes the device as radioactive in nature.

[006] Patent 20070160176 differs from the present technology because it is based on reactions (n,2n), which requires specific targets for this purpose, in addition to the other drawbacks mentioned.

[007] In continuity, some patent documents associated with the production processes of radioisotopes, AC, RT, GR, are presented below. - Production from irradiation with accelerated particles, AC: in “Device and method for producing radioisotopes” - US7940881, the authors propose to transmute isotopes from the irradiation of a fluid with a beam of charged particles. Such a patent is limited to the description of the target, its form and physical state. Note that beams of charged particles are generated by particle accelerators, such as cyclotrons, synchrocyclotron or synchrotons. The radionuclides produced are rich in protons and, in general, β+ emitters or decay by electron capture. - Production from neutron irradiation (fission), RT: in “Techniques for on-demand production of medical isotopes such as Mo-99/Tc-99m and radioactive iodine isotopes including 1-131” - US20110280356, the inventor proposes to irradiate samples with neutrons derived from fission from uranium. In this case, the fast fission neutrons are reflected and moderated by scattering, increasing the probability of further fissions of 238U. Sandwich layers of uranium are used to maintain the rate of neutron fission and production. In this case, the production of neutrons by fission becomes the key to supply the production of radioisotopes. - Production from a pre-existing “parent” radionuclide that decays, transmuting into another “daughter” radionuclide, GR process: in “Medicai isotope generator systems” - US7554098, the inventors propose to use a 90Sr column to produce 90Y and separate it by means of an eluent solution. This is a typical patent that features a radioisotope generator through columns containing a pre-existing radionuclide with a long half-life, which decays into a daughter radionuclide with a short half-life and can be column eluate. The “parent” radionuclide is produced by the methods described above, i.e., in nuclear reactors or particle accelerators. These are chemically separated and confined in devices or capsules, where they will decay and produce the “daughter” nuclide In this case, the “parent” nuclide, 90Sr, must be previously available, activated by other processes.

[008] The technical literature also presents patent documents with designs of neutron-generating devices: - In patent application US20130129027A1, “High flux neutron source”, of May 23, 2013, an apparatus for the production of thermal neutrons is presented and epithermic, positioned around a cylinder or spherical moderator to maximize the neutron flux in a sample centered on the moderator. In this context, the system is divided into a set of neutron generators with axial axes placed in the radial direction of a cylindrical structure Each unit produces center-directed neutrons. The neutron fluxes generated from the multiple units are used for neutron activation analysis and neutron activation analysis of ready-made gamma, in order to determine the elemental chemical concentration in a material. Neutron absorptions thermal and inelastic scattering of epithermic and fast neutrons in samples generate characteristic gamma rays that can can be used to identify the target element and its chemical concentration. A radiation detector is positioned above the apparatus in the axial direction to the sample cylinder, surrounded by neutron generating units. The patent document US2013/0129027 A1 differs from the present technology because, given its purpose of analyzing neutron activation, the structures and dimensions used are characteristic for this application, making it distinct. The multiple irradiation modules, placed radially to the axial sample cylinder, make the neutron generation system distant and, thus, susceptible to leakage with reduced neutron flux. The spectra and fluxes generated in the device US2013/0129027 are insufficient for the proposed production of radioisotopes. Consequently, the geometric parameters differ from the context proposed in this patent.- The patent US7639770B2, entitled “Cylindrical neutron generator” presents a cylindrical neutron generator with coaxial formation, having a coaxial RF antenna plasma being produced, where in this plasma are generated the deuterium ions. Neutron generation is coaxial with the ion generator. Cylinder length is as long as needed. Neutrons are generated from the collision of ions with a tritium or deuterium target. This device is designed for the production of neutrons for the purpose of application in the petroleum field, analysis of molecules, investigation and scanning of explosives in airports. Due to the lack of moderator, such a device could not produce radioisotopes, as the neutrons produced are generated by the dd or dT reaction, which are 2.45 and 14.1 MeV, respectively, and at these energies the absorption cross sections of neutrons for most nuclides is very low, with no transmutation reactions taking place. - The document US2008/0089460A1, entitled “Proton Generator Apparatus for Isotope Production”, 2008, is related to improvements in electrostatic nuclear fusion reactors for the production of neutrons, protons and generation and by-products. It has a cylindrical configuration with a polygonal internal structure in the form of a reactor that uses fusion reactions between hydrogen and its isotopes with light nuclei. The system has an elongation where there is a collision zone in which targeted impacts can be generated for isotope production by the reaction of protons with appropriate nuclides. It is observed that the document addresses the production of radioisotopes through collisions with protons. US2008/0089460 differs from the present technology by including an electrostatic inertial confinement fusion reactor core. This technology is well known in the fusion field and requires plasma to be produced and maintained in inertial confinement. In US2008/0089460, fusion reactions are generated by electrical pulses or particles that help heat the plasma. The resulting particles are neutrons and protons in a dispersed and isotropic form. However, only protons can be accelerated inside the device. In this case, the radioisotope production reactions can only occur in the collision of proton-poor nuclides, inducing the production of β+ emitters. In this case, the nuclear interactions are different from the proposed technology. In summary: document US20080089460 presents a fusion reactor with inertial confinement, where the deflection and orientations/interactions in the target involve protons colliding with proton-poor nuclides; whereas in the present application the reactions and interactions are with neutrons in neutron-poor nuclides. Thus, the geometry, functionality, process and technologies involved are divergent.

[009] In Radioisotope Generators - GR, the decay of a “parent” nuclide, into a “child”, constitutes a natural transmutation, called radioactive decay; although, the parent nuclide must be produced by artificial means by the RT or AC methods. This type of generator is viable only when the “father” has a much longer half-life than the “son”. A typical example of this technology is the commercial "Mo / "mTc generator.

[0010] In the transmutation into neutron-rich nuclides, there is a need for a neutron generating source. The production of neutrons can take place by fission reactors, RT. In fact, long half-life neutron-rich radionuclides have been produced by RT in Brazil: such as 137Cs (30 years), 60Co (5 years), 1311 (8 days). Others, rich in protons, generated by AC, such as 18F (2 h), 201Ta (62.5 h), 67Ga (78.3 h) are found in Brazil, produced in commercial cyclotrons The production of neutrons can also be established by sources sealed radioactive neutron-emitting, eg 252Cf source emitting neutrons by spontaneous fission; and, by d-d or d-t fusion reactions, for example, d-d or d-t type neutron generators, initially designed for research in the area of oil exploration. One of the main advantages of these generators is based on the cross sections of the d-d, d-t and t-t reactions, which reach significant values at relatively low acceleration voltages (few hundred kV). The essence of neutron generator technology is presented by Campos and Araújo (2010) (Araujo LW; Campos TPR “Issues on beam-plasma instability - early simulations focusing on the development of a compact neutron generator”, Vol.32, Pg 3302 , July/September, 2010) and in more detail in the master's dissertation by Araujo LW, entitled “Investigations in Compact Neutron Generators'' (UFMG/2010).

[0011] Transmutation is not only used to produce radionuclides. This technique can be used to convert long-lived radionuclides into short-lived or stable radionuclides. Thus, it is used to reduce the activity of radioactive waste or even of undesired sealed or liquid radioactive sources. In this case, the “burning” of radioactive waste produced in nuclear reactors can occur by inserting them into other reactors whose burning is produced during the process of fuel fission and production of electricity. Another possibility is chemical treatment and separation, applied in conjunction with the burning technique or not, where radionuclides are separated into classes according to their half-life and activity. These are stored in pre-selected locations to be kept for millions of years to decay into a steady state.

[0012] The transmutation of nuclear fuels has also been researched involving high energy proton accelerators (1 GeV), which through scattering reactions (p,n) in lead and bismuth nuclei, among others, produce multiple neutrons, which then they are used in the conversion of radioactive waste.

[0013] The transmutation of fissionable nuclides into fissiles, such as 232Th into 233U, can occur in nuclear reactors that employ heavy water (D2O). Classic examples are the heavy water reactors of the CANDU type, which in this case transmute 232U into 239Pu, in addition to 232Th into 233U, in addition to producing electricity.

[0014] The process of Radioisotope Generators - GR is easy to use and low cost. There are several medical centers in Brazil that use 99Mo/99mTc generators, distributed by the National Nuclear Energy Commission - CNEN. However, the country still depends on the import of "Mo irradiated in a molybdenum substrate bound to alumina. The activation of the substrate is obtained in high neutron flux reactors in Canada, Holland, Argentina, Russia, Israel or the United States, specifically in the order of 1013 to 1014 n cm'2 s'1 A recent global crisis in the supply of this input, which occurred between 2009 and 2011, due to the shutdown of high flow reactors for maintenance, impaired or even temporarily paralyzed the diagnoses made with radiopharmaceuticals labeled with "mTc in nuclear medicine. In the Brazilian case, the government solution consisted of investing in a high-flow reactor for the generation of "Mo; however, it will take at least a decade to build and operate.

[0015] In the process of Photo-Transmutation - FT, unstable isotopes emitting gamma photons or produced by braking radiation from accelerated electrons are sources of high flux of gamma radiation. The transmutation occurs through bombardment of target nuclei with gamma photons. Linear electron accelerators or even a large number of sealed sources of high activity are needed to supply gamma radiation for Phototransmutation. In FT, sealed sources are made up of unstable isotopes that continuously emit radiation; thus, logistical problems are associated due to the radiation protection associated with thousands of Ci (Curie) activity. This fact prevents the diffusion of this technology and, consequently, it is not used in the commercial production of radioisotopes.

[0016] In the process by nuclear reactors - RT, large industrial and energy facilities are required, high complexity and cost, in the order of billions of dollars, in addition, they generate concerns in terms of radiological protection and management of radioactive waste, and may still possible the occurrence of severe nuclear accidents, which bring damage to populations and the environment.

[0017] In the production process by Accelerators - AC, most of the accelerators used in the production of radioisotopes have a cost in the order of tens of millions of dollars. The radioisotopes produced by this process are rich in protons, decay by emitting β+ or by the electron capture method, and have a short half-life. There is also a need for transport management from the production facility to the consumer center. For example, cyclotrons are facilities that produce β+ emitting radioisotopes, such as 18F, 11C and 15N. Such facilities are limited to proton-rich nuclides, making it impossible to produce neutron-rich β'-emitting radionuclides. The β'-emitting class of radionuclides is produced solely with RT or FT.

[0018] The production of radioisotopes by sealed sources or neutron generators has not been used as a method of producing emitting radioisotopes (β'). The reason is that the intensity of neutrons produced by the d-d or d-t generator isotropically is in the order of 106 to 1011 n s'1 and is inversely proportional to the square of the distance from the target. Consequently, the fluence would reduce by a value around the fraction of 4πd2, for example, in relation to the distance of 100 cm from the target, the fluence would reduce by a factor of the order 7.95 x 10'6 cm. In turn, the energy of the neutrons emitted from the dd or dt reactions in neutron generators is not suitable for the production of radioisotopes, because the cross sections are very low, in the order of a few millibarns (mb = 10'27 cm2) for large most nuclides of interest. Thus, due to the inadequate energetic spectrum of the emitted neutrons, low emergence and intensity reduction with the squared distance, the use of such technology for neutron transmutation of nuclides, for medical purposes, has become fruitless. Thus, arrangements using commercial devices for radioisotope production are non-existent and impractical.

[0019] Sealed sources of 252Cf can reach surges in the order of 1012 n s'1; however, they emit gamma radiation simultaneously with neutrons, the energetic spectrum of neutrons is of fission with maximum energies of 14.1 MeV, they decay with time with a half-life of 2.7 years, the neutron emission cannot be interrupted, in addition to need to be replaced periodically.

[0020] In the case of insertion of radioactive waste in reactors, the possibility of nuclear accidents, associated with chemical explosions, make such technological processes unacceptable to our society. In Brazil, the treatment of tailings from Angra I, II and in the future III is still an insoluble problem. Transmutation by spallation reactions involves high-energy (approximately GeV) proton accelerators coupled to nuclear reactors. Such installations are expensive (billions of dollars) and are still experimental.

[0021] In the case of transmutation of thorium into uranium, light water reactors, pressurized type - PWR (Pressurized Water Reactor) cannot transmute fissionable elements into fissiles on a large scale, due to low neutron economy. For every neutron absorbed in 235U (fuel), 2.3 neutrons are emitted. The continuity of the chain reaction needs 1 neutron and the rest either escapes from the reactor or is absorbed. This is because light water (H2O) is a neutron absorber. In this way, there is a deficit of neutrons to transmute elements of interest within the reactor. Although Brazil has one of the largest reserves of 232Th in the world, its use has not yet occurred, and it is still useless to date. The transmutation of this element into a fissile element, in the case 233U, is of interest to the nation, due to the possibility of increasing the electrical production capacity by nuclear reactors.

[0022] Basically, the complexity, high cost, dimensions and radiological protection involved in the generation of radioisotopes by FT, RT and AC techniques, limit the applications of radioisotopes. Neutron-rich radionuclides, especially those with short half-lives, less than 48 h, for example, are not produced in a non-limiting manner. Obviously, the distance from the production centers by any of the FT, RT and AC techniques prevents the use of short half-life radionuclides.

[0023] In addition, the disposal of radioactive waste in locus has not yet been resolved in Brazil. Such limitations can be overcome by applying the in locus transmutation method, through activation by neutrons, generated by compact generators, supported by fusion reactions. The main advantage is characterized by the cross sections of the d-d, d-t and t-t reactions, which reach significant values at relatively low acceleration voltages (few hundred kV) used in the acceleration of these particles.

[0024] In order to solve such existing limitations both in the production of radioisotopes, as well as related patents, the present invention is proposed in order to increase: i) the supply of short half-life neutron-rich radioisotopes; ii) the independence of high flux reactor technology in the activation of "Mo, available only in a few industrialized countries; iii) the production of short half-life radioisotopes in hospitals or clinics; iv) the possibility of transmutation of half-life radioisotopes in short half-life or stable radioisotopes, in locus, solving the problem of waste produced in nuclear reactors, or from undesirable sealed sources; v) the possibility of transmuting fissionable elements into fissiles, allowing the use of the 232Th mineral reserves of the countries; vi) reducing the cost of transmuting radioisotopes; vii) replacing complex technologies, such as nuclear fission reactors and particle accelerators, with simpler and more compact technologies; viii) maintaining the philosophy of compact radioisotope generators, but without dependence on the pre-existence of a radioactive parent nuclide produced in fission reactors or particle accelerators; ix) the radiological safety of the facilities; x) and allow the total shutdown of the installation and consequently interruption of the radiation produced in the device, similar to X-ray equipment.

[0025] The present invention was then developed through the proposal of Cylindrical Isotope Transmuting Fusor Cell (CCFTI), of cylindrical shape.

[0026] The CCFTI proposal consists of employing d-d, d-t or t-t fusion neutron generation technologies and internal neutron moderation, reflection and shielding systems, together, composing a nuclear transmutation system. In this context, the CCFTI is distinguished by being a unitary system, capable of jointly administering the main electromagnetic and nuclear processes involved in the transmutation of nuclides. The system has compact dimensions, low cost compared to competing technologies, simplicity of development and operation, presenting radiological safety with the possibility of complete interruption of radiation and availability, being able to operate continuously in the production of radioisotopes, at the site of application of radioisotopes, consequently enabling the production and use of short-lived neutron-rich radionuclides.

BRIEF DESCRIPTION OF THE FIGURES

[0027] Figure 1 illustrates a longitudinal section of the cylindrical fuser cell isotope transmutator (CCFTI) with its main components and auxiliary systems.

[0028] Figure 2 illustrates two types of cross-sections, where there is an indication of differences in sample distribution (5) in an annular way in the CCFTI.

[0029] Figure 3 illustrates a radioisotope column and elution method.

[0030] Figure 4 illustrates a three-dimensional sectional view of the central region of the CCFTI.

[0031] Figure 5a shows a view of the cell receptacles showing the target electrode (1) and electrical insulator (2). Figure 5b illustrates a view of the internal structure of the CCFTI, showing the plasma electrode (3) and electrical insulators (2). Figure 5c illustrates the cylindrical plasma chamber (4), contained within the plasma electrode (3). Figure 5d shows the cross-sectional structure of the CCFTI, showing the concentric rings.

[0032] Figure 6 illustrates the shield (101) and annular cylindrical reflector (102) structures (101), the upper reflector (104) and the upper shield (103) of the CCFTI.

[0033] Figure 7 illustrates a semi-transparent three-dimensional wireframe view of the cylindrical CCFTI geometry.

[0034] Figure 8 illustrates the distribution of equipotential lines of the electrical potential generated by the plasma electrodes (3) and the target electrode (1).

[0035] Figure 9 illustrates the ion transport lines between the plasma electrode (3) and the target electrode (1), through the multiple openings in the plasma electrode (3), identifying the kinetic energy gain in the process of acceleration.

[0036] Figure 10 shows the spectrum of the neutron flux in the moderator receptacle.

[0037] Figure 11 shows the cross section of the d-d (a) and d-t (b) reactions.

DETAILED DESCRIPTION OF THE TECHNOLOGY

[0038] The present technology is proposed by a Cylindrical Isotope Transmuting Fusor Cell (CCFTI) (Figure 1), which basically consists of the following components, arranged together: a plasma chamber of cylindrical geometry (4) central to the device (Figure 5) which is generated by a radiofrequency system (110) by excitation of a central internal antenna (105) (Figures 1, 2 and 4) producing and making available deuterium or tritium ions; a set of electrodes, (1) and (3), specifically, plasma electrode (3) and target electrode (1), which is covered internally because it is a deposited metallic film, composed of metallic hydride, which may be titanium- deuterium (TiDx), where x ranges from 0.1 to 6; (1) and (3) being electrically charged by a high power system (109); an ion acceleration environment (7) (Figure 2) characterized between the plasma (3) and target (1) electrodes where metal hydride is deposited on the inner surface (1); an annular cylindrical region (106) separating the target electrode (1) from the moderator (8) (Figure 2), containing a refrigerant and insulating fluid; an annular cylindrical shell containing a neutron moderator (8); one or more sample receptacles (5) (Figure 2), placed radially to the moderator or in the form of multiple cylindrical tubes distributed in the moderator; and an external containment composed of an annular cylinder for the neutron reflector (102) and the same for the radioactive shield (101).

[0039] The present technology (Figure 1) contains concentric cylindrical rings arranged externally to the plasma chamber, containing several parts, with equivalent longitudinal dimensions of 10 to 500 cm, characterized by having a plasma chamber (4), sample container ( 5), taking the form of a concentric annular ring, plasma electrode (3), provided with 1 to 100 openings per square centimeter, cylindrical, conical, or sector of a sphere; a target electrode (1), cylindrical in shape, coated on the inner wall with deposited metal hydride; separator insulators (2) at the top and bottom and radius equivalent to the target electrode, useful in electrical insulation; moderator annular cylindrical ring (8); ion acceleration environment (7), 1 to 5 cm in radial thickness; and, moderator container (6).

[0040] The moderator container (6) contains the moderator (8) and the sample receptacle (5) can be summarized in a single part, where in this case the samples (5) are immersed in the moderator material (8).

[0041] More specifically, the CCFTI (Figure 1) comprises a cylindrical device, with internal concentric cylindrical structures, with axial lengths ranging from 1 to 400 cm, comprising a cylindrical plasma chamber (4), fed with deuterium gas (108), provided with a system for producing plasma (110), which can be generated by an internal RF antenna (105); a set of cylindrical electrodes fed by conductors (119) by the high voltage system (109) with a potential difference from 0 to 400 kV, being a plasma electrode (3), with an internal radius of 2 to 50 cm with a radial thickness of 0.1 to 1.5 cm, equipped with 1 to 100 radial openings per square centimeter of surface, each opening having an average width of 0.05 to 0.5 cm, the openings being cylindrical and longitudinal rectangular in shape, or even conical shape, toroidal trunk or spherical cap; plasma chamber (4), cylindrical, with an internal radius of 3 to 30 cm; an acceleration environment (7) in the form of a cylindrical halo, with an inner radius of 3 to 50 cm and an outer radius of 5 to 50 cm; target electrode (1), with an internal radius of 4 to 50 cm with a radial thickness of 0.1 to 3 cm, internally coated with metal hydrides; refrigerant fluid and insulator (106), and recirculation system (107) maintaining external contact with the target (1), contained in a concentric annular cylinder (106); moderator container (6), in the form of a cylindrical halo, with an internal radius of 4 to 50 cm and an external radius of 10 to 100 cm; containing the moderator (8), sample receptacle (5), or in the form of a single cylindrical annular concentric sample position volume (5), external to the moderator (8), with an internal radius of 5 to 100 cm and an external radius of 10 to 110 cm, or in the form of multiple cylindrical sample receptacles (5) with a radius of 1 to 10 cm, distributed in the moderator (8), with axial entry from the lid (151), tube (153) or columns (155) elution and access tubes (154), protected by reflector (150) and (152); and, constricted by a cylindrical reflector ring (101) and shield (102), in the same way, covering the cell, and cover (151), with reflector and shield, of material thicknesses from 5 to 50 cm; the target (1) and plasma (3) electrodes are made of copper, aluminum, titanium, or metallic alloy; target (1) represented by the deposit of a metallic film composed of metallic hydride, which may be titanium-deuterium (TiDx), where x varies from 1 to 6; moderator (8) consisting of light water (H2O), heavy water (D2O), graphite, high density polymers, fluorinated polymers, polyethylene, teflon, beryllium compounds, sulfur, or mixtures thereof; electrical insulators (2), on the unexposed face of the target electrode and on the joints and edges of the electrodes, made of dielectric material such as glass, special ceramics or rubber; and electrical connections (119), of copper or aluminum cables; refrigerant (106) consisting of a thermal refrigerant fluid and electrical insulator, such as mineral or organic insulating oil; reflector (101) consisting of material composed of chromium, copper, bismuth, lead, tungsten carbide or alloys or mixtures thereof; shielding (102) composed of polyethylene, water, or graphite, mixed with neutron-absorbing substances, such as boron, lithium, cadmium, or gadolinium compounds, and coated with bismuth, lead, or tungsten carbide; and plasma chamber gas (1) of neutral deuterium, or enriched with gaseous tritium.

[0042] The moderator container (6) and the sample receptacle (5) can constitute a single element, so that the target nuclides can be inserted and combined to the moderator.

[0043] The CCFTI can connect to a radio frequency (RF) system (110), a high voltage system (109) with feed connections (119) for the electrodes, and the deuterium gas feed system (D2) ) (108), as well as an external cooling system (107).

[0044] The present device proposes a geometrically adequate structure, using appropriate materials, that is, the configurations of materials and geometries allow maximizing the emergence of neutrons, reducing leakage by neutron reflection, capable of generating a flow of neutrons in a set of receptacles and transmuting nuclides producing radioisotopes, among other applications. This neutron flux originates from the d-d or d-t nuclear reactions, and the deuterium ions, generated in plasma fed by radiofrequency, are extracted from the cylindrical inner chamber by an electrified plasma electrode and target; accelerated by the difference in potential present between these electrodes, colliding with the target consisting of titanium, silver, steel, gold, copper or tungsten, coated with metallic hydrides or also with Ti, Ag, Au, Cu or W, these deuterized or tritiated, promoting nuclear fusion reactions at the target.

[0045] The cylindrical shape helps contain the plasma. The RF antenna produces the excitation and ionization of the deuterium gas, and the electrodes promote the extraction of ions from the plasma through the plasma electrode (3), in a radial direction, colliding them against the inner surface of the target electrode (1) .

[0046] Through the isolation and cooling of the electrode (1) of high potential, the moderator (8) can be brought closer to it, allowing neutrons to lose their energies by elastic collisions and allow reaching plausible kinetic energies for absorption and capture reactions to occur radioactive, preferably in the thermal range, in sample receptacles (5). Thus, radioisotope generation processes such as GR, FT, AC and RT become outdated and unnecessary.

[0047] The present technology is compact, simpler (compared to nuclear reactors and particle accelerators), and capable of producing radioisotopes, or transmuting various isotopes or radioisotopes of interest, at the place of use, for example, in hospitals, clinics, research centers, radioactive waste production sites, at a low cost.

[0048] Another relevant aspect when it comes to the production of radioisotopes is the ability that the present technology has to turn on and off, via radiofrequency power and high electrical potentials, in the order of 200 kV, interrupting the d-d or d-t reactions. Thus, when turning off, the device stops producing radiation. Contrary to nuclear reactors (RT), which do not cease to produce radiation, and adverse to technologies that use neutron production by 252Cf sources, or photodisintegration reactions (FT) such as (y,n); CCFTI becomes attractive because it does not produce radiation when turned off.

[0049] Another relevant aspect of the present technology is in the comparison of the production of radioisotopes by generators, defined here by GRs. In GRs there is a need for a precursor, called “parent”, radioactive, to be produced in advance in nuclear reactors. The distribution of generators such as "Mo/"mTc are made weekly, and show an eluted activity, decaying in the time of the parent's half-life, for example, 67 h of "Mo. The balance of activities between "Mo and "mTc is said to be transient. In the presented technology, the CCFTI can continuously generate the "father", whose internal activity in the device becomes constant, and consequently the balance between the "father" and "son" becomes secular. It is possible to make the “daughter” radioisotope unlimitedly available, without the need for periodic exchanges of the GRs.

[0050] Regarding the main components of the CHFTI (present invention), as well as its functionalities, the CHFTI consists of: Plasma generation system (110), (105), (3) and (4): represented by a camera ( 4), fed by D2 gas (108), which feeds plasma (4), which is generated by radiofrequency (110), and extracts deuterium ions through the plasma electrode (3). In the case of plasma generated by RF radiofrequency, the system consists of a radiofrequency generator, impedance matching network, power amplifier, and the antenna is positioned internal (105) to the plasma chamber (4), fed by a system of radiofrequency power (110) in the order of 0.5 to 5 KW at a frequency of 13.5 MHz, which allows the ionization of the D2 gas (108). RF power systems, applied frequency and power for plasma generation, their variations, are part of plasma technology, and are common knowledge, and will not be described in this patent. D2 gas storage and distribution system (108) (Fig.1): consisting of a cylinder with pressurized deuterium gas (108), pressure control valves, which must establish within the plasma chamber (4) a pressure in the order of approximately 0.27 Pa, and tubes or hoses and connectors leading to the plasma chamber (4). Set of Electrodes, (1) and (3): responsible for defining a beam of hydrogen isotope nuclei, deuterium (d) or tritium (t) ions. A fixed individual voltage is applied to the electrodes, ranging from 30 kV to -150 kV, and the potential differential between electrodes can reach 180 to 200 kV. The electrodes are responsible for extracting, focusing and accelerating deuterium ions. The following can be presented in this set: the plasma electrode (3), the suppressor electrode, the ground electrode, the focusing electrode and the electrode associated with the target (1). Suppressing, grounding, and focusing electrodes are optional and assist in the orientation, electron suppression, and collimation of the deuteron beam against the target. High voltage power system (109): high voltage generator up to 400 kV that feeds the electrodes, through cables (119) and electrical insulators. Refrigerated target (1): consisting of metal hydrides deposited on the metal electrode plate of the target (1), where dd (deuteron-deuteron), dt (deuteron-triton) or tt (triton-triton) fusion reactions take place. generating neutrons. Cooling system (107): heat exchanger and coolant fluid (106), which enters through conduits (117) to the CCFTI, consisting of insulating oil, which flows over the external surface of the target electrode (1), maintaining contact with the target, enveloping it in order to absorb the thermal energy deposited on the target by the accelerated ions. If the thermal power is high, you can choose to introduce an external heat exchanger to the CCFTI device, cooling the fluid contained in it, in order to transfer heat to a secondary fluid such as water or air. Moderator container (6): a receptacle, where there is a neutron moderation material called moderator (8), of adjustable dimensions, in order to optimize the energetic spectrum of the neutron beam to the transmutation of interest, maximizing the transmutation reaction rate. Sample receptacle set (5): place for introducing samples to be transmuted, arranged internally to the moderator (8); and/or on the central axis of the CCFTI. Neutron Reflector (102): A neutron reflecting shell, which minimizes neutron leakage or absorption in order to confine neutrons within the moderator. Shield (101): external housing that limits radioactive exposure to the vicinity of the device during the period of operation.

[0051] Among some materials that can be used in the constitution of the main components of the present invention, it is mentioned: Target electrodes (1) and plasma (3), and other optional ones: metallic parts, composing surfaces, with multiple perforations in the cylindrical shape, frustoconical section, or sphere section, consisting of copper, aluminum, titanium, silver, gold, or metallic alloy, in a non-limiting manner. Target (1): metallic film deposited on the target electrode (1), composed of metallic hydride, which may be titanium-deuterium, TiDx (x=0.1 to 6), in a non-limiting way; Moderator (8): neutron moderator material such as light water (H2O), heavy water (D2O), graphite, high density polymers, fluorinated polymers, polyethylene, teflon, beryllium compounds, sulfur, or mixtures thereof, so not limiting. Reflector (102): material composed of chromium, copper, bismuth, lead, tungsten carbide or alloys or mixtures thereof, in a non-limiting manner. Electrical insulator (2): electrical insulating material, which can cover the unexposed face of the target electrode, the joints and edges of the electrodes, and electrical connections, between these conductive materials and other parts of the device, consisting of dielectric material such as glasses, special ceramics, rubber, in a non-limiting way. Refrigerant (106): refrigerant fluid that circulates external to the target electrode (1), also functioning as an electrical insulator, commonly used in electrical transformers, as mineral or organic insulating oil, in a non-limiting way. Shielding (101): composed of polyethylene, water, or graphite, mixed with neutron-absorbing substances, such as boron, lithium, cadmium or gadolinium compounds, and coated with bismuth, lead, cadmium or tungsten carbide, in a non-limiting way. Filling gas (4): the feed gas contained in the plasma chamber (4) is neutral deuterium gas, or gas enriched with tritium gas.

[0052] Figure 1 illustrates a longitudinal section of the cylindrical CCFTI. In this one, the inlets of the deuterium gas (108) that feeds the plasma chamber (4) and the acceleration environment (7) can be observed. It is also observed the electrical conductors of the RF system (110) for feeding the radio frequency antenna (105). The high voltage system (109) and the high voltage electrical conductors HV1 and HV2 can be identified for the plasma electrode (3) and target electrode (1) (Fig.1 and 4). There are electrical insulators (2) on both the top and bottom, isolating the electrodes and antenna. The inlet of the insulating fluid (106) and refrigerant of the refrigeration system (107) is observed, which circulates in a cylindrical annular ring (106) that maintains the function of refrigeration and insulation of the target (1). The shield (101), the moderator container (6) and the moderator material (8) can also be observed. The inlet of the sample receptacle (151) and the sample placement space (5) are also observed.

[0053] Figures 2a and 2b show the cross-sections of the CCFTI showing the shield (101), the reflector (102), a single cylindrical annular concentric sample position volume (5) (Fig.2b) or in the form of a cylinder assembly (5) as in Fig. 2a. The longitudinal cylindrical antenna (105) can also be seen, which may also be helical, internal to the plasma chamber (4); as well as the acceleration space (7) between plasma and target electrodes. Also shown is the annular concentric cylindrical volume (106) referring to the coolant and liquid insulator that circulates and cools the target electrode; the moderator ring volume (8).

[0054] Figure 3 shows more details of the sample tube (153). The transmutation column (155) holds the nuclides to be transmuted. This column may contain: i) nuclides whose precursor is stable and generates a radioactive product useful for commercial purposes; ii) a radionuclide that can be transmuted into a stable one, or into a series of radionuclides that lead to a stable one, in this case “burning or eliminating” the radioactive nuclide; iii) a long half-life radionuclide into a short half-life radionuclide, in this case “burning or removing” half-life radionuclide from one to thousands of years; iv) a short half-life radionuclide into a long half-life radionuclide, for commercial purposes; v) a stable nuclide that transmutes into a radionuclide, which undergoes subsequent decay with a half-life longer than the half-life of its radioactive by-product, which has a lower half-life, and in this case composes a transient or secular equilibrium parent-child radioisotope generator , in which case an elution process is provided where thin tubes (154) enter and leave the column fed by eluent (156) and vacuum (157) vials.

[0055] Figure 4 illustrates a three-dimensional view of the inner part of the cylindrical CCFTI, where the radio frequency antenna (105) inside the plasma chamber (4) is identified, confined by the plasma electrode (3), followed by the acceleration environment (7) and by the target cylinder (1). After the target (1), in contact with it, there is the cylindrical annular ring where the insulating and refrigerant fluid (106) is stored and circulated. The moderator container (6) can also be identified, where there is the moderator material (8), and the sample receptacles (5) are immersed in it, which is presented here in a cylindrical shape. Also follows the shield (101) and the reflector housing (102) with reflective material (102).

[0056] Figure 5a shows a view of the target electrode (1), concentric annular cylindrical. On its top and bottom faces there is a ring of insulating material (2). Fig.5b illustrates the electrical insulators (2) and the plasma electrode internal (3) to the target electrode (1). Fig. 5c illustrates the plasma chamber (4) and the plasma electrode (3) with their multiple openings. In figure 5d, the sample receptacle is represented by a single concentric annular cylinder (5). Also shown are the moderator (8) the moderator container (6), the target electrode (1), the acceleration space (7), the plasma chamber (4).

[0057] The entire CCFTI cell is coated with a reflective material (102) and a shield (101). There is a cover that has the same constitution: a reflector (104) and shield (103). (Figure 6a and 6b)

[0058] Figure 7 illustrates the structure of the reflector (102) and the shield (101), in a three-dimensional wired view of the CCFTI.

[0059] Figure 8 illustrates the equipotential lines between the plasma electrodes (3) and the target electrode (1), which received a potential difference of 180kV.

[0060] Figure 9 represents the transport of deuterium ions between the plasma and target electrodes, also showing its gain in kinetic energy between these electrodes.

[0061] A peculiar feature of the cylindrical device is the containment of the plasma, which is presented in the center of the device, where the moderator (8) and the sample housing (5) are located in the surroundings, forming concentric cylindrical layers, outlining a geometry cylinder for the CCFTI.

[0062] Figures 2, 3 and 4 show the cylindrical structures of neutron reflection and shielding (external) of the CCFTI with cylindrical geometry, where the following are identified: a) structure of the radiation shield (101), with a radial thickness of 3 at 80 cm, outside the concentrically coupled neutron reflection structure (102); b) solid cylinders, with a thickness of 3 to 50 cm, to close the top (103) and bottom (101) of the reflector (102) and the shield (101).

[0063] The cylindrical CCFTI is then confined by an inferior, superior and lateral reflection system. The side reflector (102), which has a radial thickness of 1 to 50 cm, is illustrated in Figure 2, where the top cover (104) for neutron reflection is shown. After this structure, there is the confinement by the lateral (101) and lower and upper shields, uniquely numbered (103),

Onde d equivale ao dêuteron, n o nêutron, 2H ao átomo de deutério, 3H ao átomo de trítio e 1H equivale ao hidrogênio, 3He e 4He isótopos do átomo de hélio. Q representa a energia cinética dos produtos da reação, onde n é emitido com 2,45 MeV em reações d-d e 14,06 MeV para d-t. As reações 5 e 6 podem ocorrer no alvo, isto é d-d, que geram (d,n) e (d,p). Entretanto somente a reação 6 apresenta como subproduto a emissão de nêutrons. As seções de choques (probabilidade de interação) para as reações (d,n’), (d,p), (d,d), (t,n), obtidas do banco de dados ENDF/B-VI.8, são apresentadas na Figura 10.[0064] At the target electrode (1) the nuclear reactions occur, dd or dt as indicated in the expressions below:

Where d is equivalent to the deuteron, in the neutron, 2H to the deuterium atom, 3H to the tritium atom and 1H is equivalent to hydrogen, 3He and 4He isotopes of the helium atom. Q represents the kinetic energy of the reaction products, where n is emitted with 2.45 MeV in dd reactions and 14.06 MeV for dt. Reactions 5 and 6 can occur on the target, ie dd, which generate (d,n) and (d,p). However, only reaction 6 presents as a by-product the emission of neutrons. The cross sections (interaction probability) for the reactions (d,n'), (d,p), (d,d), (t,n), obtained from the ENDF/B-VI.8 database, are shown in Figure 10.

Onde Qd é o número de dêuterons por cm3 no alvo, / é a corrente do feixe, add(E) é a seção de choque para produção de nêutrons da reação de fusão d-d em função da energia E do feixe de dêuterons. As espécies iônicas foram ponderadas pela sua fração fk e pelo número de núcleos k por íons. A expressão dE/dx representa o poder de frenagem do alvo carregado com deutério. A equaçãol foi resolvida numericamente, discretizando a energia em intervalos de 30 keV e estimando a densidade de dêuterons no alvo pd igual a 3,76 g.cm'3, com base no relatório técnico de 1954, da Universidade da California, intitulado: ‘"Information on the Neutrons Produced in the H3(d,n) He4”, de Jack Benveniste and Jerry Zenger.A Lei de Bragg foi empregada para determinar o poder de frenagem no alvo, ela é apresentada por meio da equação 2 e é descrita por Heaton, R.; Lee, H.; Skensved, P. e Robertson, B. na publicação da Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 276(3):529 - 538, 1989).

onde o índice M representa o metal e d representa o deutério no alvo. Os valores do poder de frenagem podem ser obtidos por meio do código Srim.[0065] The determination of the neutron yield, y, of the CCFTI can be evaluated through equation 1, as follows:

Where Qd is the number of deuterons per cm3 in the target, / is the beam current, add(E) is the neutron production cross section of the dd fusion reaction as a function of the energy E of the deuteron beam. The ionic species were weighted by their fraction fk and the number of nuclei k per ions. The expression dE/dx represents the braking power of the target charged with deuterium. The equation was solved numerically, discretizing the energy in 30 keV intervals and estimating the deuteron density in the pd target equal to 3.76 g.cm'3, based on the 1954 technical report from the University of California entitled: '"Information on the Neutrons Produced in the H3(d,n) He4”, by Jack Benveniste and Jerry Zenger. by Heaton, R.; Lee, H.; Skensved, P. and Robertson, B. in the publication of Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 276(3):529 - 538 , 1989).

where the index M represents the metal and d represents the deuterium in the target. Braking power values can be obtained from the Srim code.

onde À representa a constante de meia vida do radionuclídeo, produto da transmutação. A taxa de transmutação volumétrica Rv pode então ser obtida por meio da equação 4.

(4) onde p representa a densidade do material representativo da amostra (Z), NA O número de Avogadro, A é a massa atômica do composto contendo isótopo Z a ser transmutado, co é a fração química multiplicada pela fração isotópica do isótopo Z no composto, e Oz(E) a seção de choque de absorção neutrônica do isótopo em questão e Φ(E,r) o fluxo de nêutrons no moderador (8) na posição r (da amostra), ambos dependente da energia, e yo rendimento de nêutrons gerados pelas reações d-d, que significa a surgência de nêutrons no alvo. O termo <cyz(E).Φ(E,r)>/Y é avaliado pelo código MCNP em uma determinada posição r do moderador, e integrado no domínio do espectro energético, entre a energia térmica a 2,5 MeV. Os resultados destes cálculos para algumas amostras são apresentadas nos exemplos.[0066] After obtaining the neutron yield, equation 1, referring to the source of neutron emission distributed in the target, the spatial distribution of neutrons and its spectrum in the volume of the moderator (8) is calculated, in an attempt to evaluate the degradation of the fast spectrum (2.45 MeV emitted by dd, for example) in the thermal spectrum. In the regions where the samples are located, the macroscopic cross section of the material to be irradiated is obtained, multiplying the microscopic transmutation cross section (generally, of radioactive capture, (ny)), dependent on energy, by the neutron spectrum, normalized by the yield of neutrons by the source, and, finally, by the volumetric density of atoms to be transmuted, in atoms-cm3. Then, the temporal and volumetric rate of radioisotope transmutation is calculated, defined as Rv, in units of nuclides produced “nr” per unit volume, cm3 , per unit of fluence emitted by the source, ie n.s'1. This is multiplied by the yield y of the CCFTI and inserted in equation 3, in order to define the activity of the sample as a function of the irradiation time.

where A represents the half-life constant of the radionuclide, the product of transmutation. The volumetric transmutation rate Rv can then be obtained from equation 4.

(4) where p represents the density of the representative material in the sample (Z), NA Avogadro's number, A is the atomic mass of the Z-isotope-containing compound to be transmuted, co is the chemical fraction multiplied by the isotope fraction of the Z-isotope in the compound, and Oz(E) the neutron absorption cross section of the isotope in question and Φ(E,r) the neutron flux in the moderator (8) at position r (of the sample), both energy dependent, and yo yield of neutrons generated by the dd reactions, which means the emergence of neutrons in the target. The term <cyz(E).Φ(E,r)>/Y is evaluated by the MCNP code at a certain position r of the moderator, and integrated into the energy spectrum domain, between the thermal energy at 2.5 MeV. The results of these calculations for some samples are presented in the examples.

[0067] Regarding plasma (4), this is non-thermalized, and can be produced in the plasma chamber (3) at low temperature. Plasma can also be generated by electrical discharges, in continuous operation (CW) or pulsed, capacitively and inductively coupled to radiofrequency discharges, antenna discharges, and microwave discharges in closed cavities, or even in open structures. Coupled capacitive discharge can occur between two parallel plates or transverse electrodes where an alternating potential difference is applied. The coupled inductive discharge is generated by the induction of a coil. Plasma (4) can also be generated by a strong electromagnetic field applied with a laser or microwave generator, or by applying a strong electric field to a gas where the Townsend avalanche process takes place. The Townsend discharge process is an ionization process where free electrons are accelerated by an electric field strong enough to generate an electrical conduction in the gas in the form of an avalanche multiplication caused by the impacts of ions and ionized molecules. The generation of plasma by radiofrequency RF, as presented, is of interest due to the need for long-term operation. Electrical discharges applied by the plasma generator can be classified by the frequency of the excited field, ranging from kHz to MHz, classified as: by direct current discharges (DC); pulsed DC discharges (kHz); radiofrequency discharges (MHz), supported by ohmic and stochastic electron heating mechanisms; by microwave discharges (GHz); by laser generated plasma; or by discharges of oriented electron beams. In summary, there are several forms of plasma generation, whose science and technology are in the public domain. The change in the form of plasma generation in the plasma chamber, described in this patent, maintaining similar geometry, material or components, and preserving the use, do not characterize a new invention, but only represent changes in the form of ionization of deuterium gas, supported scientific and technical information of common knowledge.

[0068] The fuser cell is characterized by being a device for the isotopic transmutation of nuclides from the generation of neutrons by nuclear fusion between deuterium (d) and/or tritium (t) ions. In this way, it can be a device for the isotopic transmutation of fissionable elements into fissiles, preferably 232Th and 238U.

[0069] CCFTI can produce isotopes and radionuclides, preferably from the group comprising: Na-24, P-32, S-35, CI-38,Ar-41, K-42, Ca-47, Ca-49, Ti- 51, V-52, Cr-55, Mn-56, Fe-59, Co-60, Ni-65, Cu-64, Cu-66, Zn-69, Zn-71, Zn-72, Ga-70, Ga-72, Ge-72, Ge-75, As-76, Se-81, Se-83, Br-80, Br-82, Kr-87, Kr-85, Kr-81, Kr-79, Rb- 86, Rb-88, Sr-85, Sr-87, Sr-89, Sr-90, Y-90, Mo-99, Ru-105, Ru-106, Rh-104, Pd-103, Pd-107, Ag-108, Ag-110, Ag-111, Ag-113, Cd-111, Cd-115, Cd-117, ln-114, ln-116, ln-114, ln-116, Sn-125, Sn- 121, Sn-123, Sb-122, Sb-123, Sb-125, Te-121, Te123, Te125, Te-127, Te-129, Te-131, I128, 1-131, Xe-125, Xe- 127, Xe-129, Xe-131, Xe-133, Xe135, Xe-137, Cs-134, Ba-133, Ba-135, Ba-139, Ba-130, La-140, Ce-137, Ce- 139, Ce-141, Ce-143, Pr-142, Pr-143, Nd-147 Nd-149, Nd-151, Sm-151, Sm-153, Sm-155, Eu-152, Eu-154, Eu -155, Eu-156, Gd-153, Gd-159, Gd-161, Tb-160, Dy-157, Dy-159, Dy-165, Dy-166, Ho-166, Er-169, Er-171 , Tm-170, Yb-169, Yb-175, Yb-177, Lu-177, Hf-175, Hf-181, Hf-182 , Hf-177, Hf-178, Hf-179, Ta-182, W-181, W-185, W-187, W-188, Re-188, Os-193, lr-192,lr-193,lr -194, Pt-191, Pt-193, Pt-195, Pt-197, Pt-199, Au-1998, Au-199, Hg-197, Hg-199, Hg-203, Hg-205, Ti-204 , Ti-206, Pb-205, Pb-209, Bi-201, Bi-211, Th-233, U-239.

[0070] CCFTI can be used in the transmutation of one or more long-lived radionuclides, precursors of short-lived radionuclides, this pair being defined in the group: Mo-99/Tc-99m, Sr-90/Y- 90, Rb-81/Kr-81m, Hg-195/Au-195m; W-188/Re-188, S1-32/P-32.

[0071] This device can be used in the activation of radioactive seeds for brachytherapy, including ceramic seeds based on bioglass, or nanoparticles, phytates or macro-aggregates based on oxides, phosphates, silicates, carbonates, as well as radioactive inputs based on nitrates and chlorides, or polymers incorporating radioisotopes emitting X-rays, gamma or beta-rays, in a non-limiting manner.

[0072] CCFTI may be useful in transmuting long-lived radionuclides into short-lived or stable radionuclides, of interest in burning radioactive waste or reducing the activity of unwanted radioactive sources, represented by materials incorporating one, or a set of nuclides, belonging to the group of chemical elements: californium, berkelium, curium, americium, plutonium, neptunium, uranium, protactinium, thorium, actinide, radium, strontium, iodine, cesium, cobalt, iron, sodium, in a non-limiting way.

[0073] The present technology can be better understood through the following non-limiting examples.

Example 1: Electromagnetic evaluation of the CCFTI

[0074] As an example of electromagnetic evaluation, the electrical potential distribution of a CCFTI based on annular concentric cylinders simulated in the CST code (Computer Simulation Technology) is presented. In this, an electrical potential of 30 kV was used at the plasma electrode (1) and -150 kV at the target electrode (3). The profile of the equipotential lines is shown in Figure 8.

[0075] As a result of the simulation, Figure 9 shows the energy profile of the deuteron beams, representing their trajectories towards the target. The presented configuration allowed to reach a current of 1.588 A of deuterons in each target.

Example 2: Neutral yield on target

[0076] The calculation of the neutronic efficiency y was evaluated through equation 1. The values of the braking power were obtained through the Srim code. With the hemispherical configuration with 310 openings in the plasma electrodes, a surge of 1013 n s"1 was reached.

Example 3: Neutronic evaluation of CCFTI of cylindrical geometry

[0077] As an example of nuclear evaluation, a model of the CCFTI of cylindrical geometry was elaborated, simulated in the MCNP5 code (Monte Carlo N-Particle). The materials used in this evaluation were: dry air (outdoor environment), shielding (bored polyethylene, density of 1.12 g.cm'3), reflector (chromei, density 10.27 g.cm'3), receptacles (of stainless steel, density 8.0 g.cm'3), insulator (of kaolinite, 2.50 g.cm'3), plasma chamber filled with deuterium gas (density 0.01 g.cm'3), plasma and target electrodes (copper, density 8.50 g.cm'3), deuterium gas acceleration environment (0.001 g.cm3), target (copper, titanium deuterium, 8.50 g.cm'3 ), reflector (from bismuth and lead alloy, density 10.27 g.cm'3), and moderator (from graphite, 1.70 g.cm'3, and light water, 1.0 g.cm'3) .

[0078] The neutron flux was evaluated in simulations in the MCNP5 code, which performed the transport of neutrons in the CCFTI, since its emission in the target (1) appearing with fast energy (2.45 MeV) and its thermalization in the moderator volume ( 8) up to sample placement volumes (5).

[0079] Figure 10 shows the spectrum of the neutron flux in the phase external to the target (1), near the edge of the moderator receptacle (6), and in the position of the sample receptacle (5). It is observed that the amount of fast neutrons, of 2.5 MeV, reduces and the amount of thermalized neutrons increases. This change in the neutron spectrum helps to increase the rate of transmutation of the isotopes of interest.

Example 4: Activity evaluation of transmuted samples

[0080] The activity obtained by transmutation was evaluated through computer simulations via MCNP code and numerical calculations.

[0081] The normalized neutron fluence per particle emitted by the source in internal volumes in the moderator was calculated using the MCNP5 code. The fluence was multiplied by the atomic density of the samples of interest and by the radioactive capture cross section, (n,y), resulting from the isotopic transmutation of the atoms of interest; determining, then, the temporal and volumetric rate of radioisotope transmutation, defined as Rv. This was multiplied by the CCFTI neutron yield y and inserted into equation 3.

[0082] Considering the Lu-176 oxide as a sample, with a natural abundance of 2.59%, the transmutation leads to the formation of Lu-177, with a half-life of 6.7 days. The result of the temporal and volumetric transmutation rate Rv for the Lu-176 samples, transmuting to Lu-177 in radioactive capture reactions (n,g), per neutron emitted at the target, inside the moderator receptacle, is 2.46365 in units of (at.b'1.cm'1).(cm'2)*(b) or (at.cm'3), per unit of source emergence, in ns-1. In this case, this is the term (<oz(E).<j)(E,r)>/y) evaluated in the MCNP code, based on a geometric model of CLFTI using the ENDF- B.8, where b is barn, in units of neutron emitted at the target, at the highest reaction rate position, at the periphery of the moderator, and inside the moderator.

[0083] Considering a surge of 1012 n.s'1, we will have 4.8 Ci.cm"3. This activity is reached after 30 days of operation. In this way, the radioactive tracer Lu-177 can be produced in sufficient quantities to meet diagnostic imaging by scintigraphy in clinics and hospitals on a daily basis.

Claims (3)

1) FUSER CELL, characterized by being a cylindrical device, with internal concentric cylindrical structures, with axial lengths ranging from 1 to 400 cm, comprising a cylindrical plasma chamber (4), fed with deuterium gas (108), equipped with a system for producing plasma (110), which can be generated by an internal RF antenna (105); a set of cylindrical electrodes fed by conductors (119) by the high voltage system (109) with a potential difference from 0 to 400 kV, being a plasma electrode (3), with an internal radius of 2 to 50 cm with a radial thickness of 0.1 to 1.5 cm, equipped with 1 to 100 radial openings per square centimeter of surface, each opening having an average width of 0.05 to 0.5 cm, the openings being cylindrical and longitudinal rectangular in shape, or even conical shape, toroidal trunk or spherical cap; plasma chamber (4), cylindrical, with an internal radius of 3 to 30 cm; an acceleration environment (7) in the form of a cylindrical halo, with an inner radius of 3 to 50 cm and an outer radius of 5 to 50 cm; target electrode (1), with an internal radius of 4 to 50 cm with a radial thickness of 0.1 to 3 cm, internally coated with metal hydrides; refrigerant fluid and insulator (106), and recirculation system (107) maintaining external contact with the target (1), contained in a concentric annular cylinder (106); moderator container (6), in the form of a cylindrical halo, with an internal radius of 4 to 50 cm and an external radius of 10 to 100 cm; containing the moderator (8), sample receptacle (5), or in the form of a single cylindrical annular concentric sample position volume (5), external to the moderator (8), with an internal radius of 5 to 100 cm and an external radius of 10 to 110 cm, or in the form of multiple cylindrical sample receptacles (5) with a radius of 1 to 10 cm, distributed in the moderator (8), with axial entry from the lid (151), tube (153) or columns (155) elution and access tubes (154), protected by reflector (150) and (152); and, constricted by a cylindrical reflector ring (101) and shield (102), in the same way, covering the cell, and cover (151), with reflector and shield, of material thicknesses from 5 to 50 cm; the target (1) and plasma (3) electrodes are made of copper, aluminum, titanium, or metallic alloy; target (1) represented by the deposit of a metallic film composed of metallic hydride, which may be titanium-deuterium (TiDx), where x varies from 1 to 6; moderator (8) consisting of light water (H2O), heavy water (D2O), graphite, high density polymers, fluorinated polymers, polyethylene, teflon, beryllium compounds, sulfur, or mixtures thereof; electrical insulators (2), on the unexposed face of the target electrode and on the joints and edges of the electrodes, made of dielectric material such as glass, special ceramics or rubber; and electrical connections (119), of copper or aluminum cables; refrigerant (106) consisting of a thermal refrigerant fluid and electrical insulator, such as mineral or organic insulating oil; reflector (101) consisting of material composed of chromium, copper, bismuth, lead, tungsten carbide or alloys or mixtures thereof; shielding (102) composed of polyethylene, water, or graphite, mixed with neutron-absorbing substances, such as boron, lithium, cadmium, or gadolinium compounds, and coated with bismuth, lead, or tungsten carbide; and plasma chamber gas (1) of neutral deuterium, or enriched with gaseous tritium. 2) FUSER CELL, according to claim 1, characterized in that the moderator container (6) and the sample receptacle (5) can constitute a single element, so that the target nuclides can be inserted and combined with the moderator. 3) FUSER CELL, according to claims 1 and 2, characterized by connecting to a radio frequency (RF) system (110), a high voltage system (109) with power connections (119) for the electrodes, and the deuterium gas supply system (D2) (108), as well as an external cooling system (107).

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