scholarly journals A Review of Radioactive Wastes Production and Potential Environmental Releases at Experimental Nuclear Fusion Facilities

Environments ◽  
2020 ◽  
Vol 7 (1) ◽  
pp. 6
Author(s):  
Sandro Sandri ◽  
Gian Marco Contessa ◽  
Marco D’Arienzo ◽  
Manuela Guardati ◽  
Maurizio Guarracino ◽  
...  
Keyword(s):  
Nuclear Fusion ◽  
High Energy ◽  
Point Of View ◽  
Neutral Beam ◽  
Fusion Reactions ◽  
Neutral Beam Injector ◽  
Main Components ◽  
Under Construction ◽  
Toroidal Geometry ◽  
High Neutron

The development of experimental nuclear fusion facilities and the systems connected to them currently involves the operation (or advanced design) of some large plants in the national territory. Devices such as neutron generators and plasma focus systems are also included. The machines developed to test the main components of these systems such as neutral beam generators (Neutral Beam Injector) and the experimental plants for thermonuclear fusion, mainly in the Tokamak configuration (toroidal geometry), are in the list. These applications are characterized by high neutron fluxes of high energy (typically 2.5 and 14 MeV from deuterium-deuterium and deuterium-tritium fusion reactions, respectively). They involve the production of radionuclides in the components of the machines and in the fluids used for targets’ cooling and in the primary containments. In many cases, the atmosphere of the rooms containing these structures is activated and may be affected by the dispersion of powders that are more or less radioactive. The present work addresses the issues mentioned so far, taking into consideration the real cases relating to the devices and the facilities in operation, under construction, and in the advanced design phase. The conclusions highlight the critical aspects related to the management of these types of waste, as well as the low or very low environmental impact, from a radiological point of view, of the examined facilities.

scholarly journals AN ADVANCED, HIGH ENERGY NEUTRAL BEAM INJECTOR

1981 ◽  
pp. 919-925
Author(s):  
J. Alessi ◽  
A. Maschke ◽  
K. Prelec ◽  
Th. Sluyters ◽  
J. Fink
Keyword(s):  
High Energy ◽  
Neutral Beam ◽  
Neutral Beam Injector

scholarly journals Hot laser fusion or low temperature nuclear reactions? Analysis and current prospects of the first experiments on laser fusion

2021 ◽  
Vol 13 (1) ◽  
pp. 59-70
Author(s):  
Vladimir I. Vysotskii ◽  
◽  
Alla A. Kornilova ◽  
Mykhaylo V. Vysotskyy ◽  
◽  
...  
Keyword(s):  
Laser Plasma ◽  
Nuclear Reactions ◽  
Nuclear Fusion ◽  
High Energy ◽  
Laser Fusion ◽  
Neutron Generation ◽  
Fusion Reactions ◽  
Target Composition ◽  
High Energy Tail ◽  
Nuclear Fusion Reactions

The paper considers the features and quantitative characteristics of the first successful laser experiments on the formation of a thermonuclear plasma and registration of neutrons in nuclear fusion reactions under pulsed irradiation of a LiD crystal. Quantitative analysis shows that the production of neutrons recorded in these experiments is not associated with thermonuclear reactions in hot laser plasma. The most probable mechanism of neutron generation is associated with nuclear reactions at low energies and is due to the formation of coherent correlated states (CCS) of deuterons. In this experiment, such states can be formed in two different processes: due to the effect of a shock wave in the undisturbed part of the target lattice on the vibrational state of deuterium nuclei or when deuterium nuclei with energy of about 500 eV move in the lattice. This part of the deuterium nuclei corresponds to the high-energy "tail" of the Maxwellian distribution of the total flux of particles entering from the laser plasma into the interplanar channel. In this second case, the process of the formation of the CCS is associated with the longitudinal periodicity of the interplanar crystal channel, which is equivalent to a nonstationary oscillator in the own coordinate system of moving particle. The expediency of repeating these experiments is shown, in which, in addition to neutrons, one should expect a more efficient generation of other nuclear fusion products due to low-energy reactions involving lithium isotopes from the target composition.

scholarly journals Selected methods of electron-and ion-diagnostics in tokamak scrape-off-layer

Nukleonika ◽  
2015 ◽  
Vol 60 (2) ◽  
pp. 199-206
Author(s):  
Marek J. Sadowski
Keyword(s):  
Nuclear Fusion ◽  
Plasma Heating ◽  
Fusion Energy ◽  
High Energy ◽  
Diagnostic Methods ◽  
Fusion Reactions ◽  
Temperature Plasma ◽  
Fast Electrons ◽  
Advantages And Disadvantages ◽  
Direct Measurements

Abstract This invited paper considers reasons why exact measurements of fast electron and ion losses in tokamaks, and particularly i n a scrape-off-layer and near a divertor region, are necessary in order to master nuclear fusion energy production. Attention is also paid to direct measurements of escaping fusion products from D-D and D-T reactions, and in particular of fast alphas which might be used for plasma heating. The second part describes the generation of so-called runaway and ripple-born electrons which might induce high energy losses and cause severe damages of internal walls in fusion facilities. Advantages and disadvantages of different diagnostic methods applied for studies of such fast electrons are discussed. Particular attention is paid to development of a direct measuring technique based on the Cherenkov effect which might be induced by fast electrons in appropriate radiators. There are presented various versions of Cherenkov-type probes which have been developed by the NCBJ team and applied in different tokamak experiments. The third part is devoted to direct measurements of fast ions (including those produced by the nuclear fusion reactions) which can escape from a high-temperature plasma region. Investigation of fast fusion-produced protons from tokamak discharges is reported. New ion probes, which were developed by the NCBJ team, are also presented. For the first time there is given a detailed description of an ion pinhole camera, which enables irradiation of several nuclear track detectors during a single tokamak discharge, and a miniature Thomson-type mass-spectrometer, which can be used for ion measurements at plasma borders.

Optimization of the extracted current density from the high energy diagnostic neutral beam injector of TdeV

1997 ◽  
Vol 68 (1) ◽  
pp. 289-291 ◽  
Author(s):  
A. H. Sarkissian ◽  
E. Charette ◽  
I. Condrea ◽  
B. C. Gregory
Keyword(s):  
Current Density ◽  
High Energy ◽  
Neutral Beam ◽  
Neutral Beam Injector

scholarly journals Vacuum System Optimization for EAST Neutral Beam Injector

Energies ◽  
2021 ◽  
Vol 15 (1) ◽  
pp. 264
Author(s):  
Guodong Wang ◽  
Si Zhang ◽  
Changqi Chen ◽  
Ning Tang ◽  
Jiaqi Lang ◽  
...  
Keyword(s):  
Vacuum Chamber ◽  
Ion Beam ◽  
Plasma Temperature ◽  
System Optimization ◽  
High Energy ◽  
Beam Line ◽  
Neutral Beam ◽  
Vacuum System ◽  
Fusion Plasma ◽  
Neutral Beam Injector

The neutral beam injector (NBI) generates a high-energy ion beam and neutralizes it, and then relies on drift transmission to inject the formed neutral beam into the fusion plasma to increase the plasma temperature and drive the plasma current. In order to better cooperate with the Experimental Advanced Superconductive Tokamak (EAST), part of the Chinese major national scientific and technological infrastructure, in carrying out long-pulse high-parameter physics experiments of 400 s and above, this paper considers the optimization of the current design and operation of the NBI beam line with a pulse width of 100 s. Based on an upgraded and optimized NBI vacuum chamber and the structure of the beam-line components, the gas-source characteristics under the layout design of the NBI system are analyzed and an NBI vacuum system that meets relevant needs is designed. Using Molflow software to simulate the transport process of gas molecules in the vacuum chamber, the pressure gradient in the vacuum chamber and the heat-load distribution of the low-temperature condensation surface are obtained. The results show that when the NBI system is dynamically balanced, the pressure of each vacuum chamber section is lower than the set value, thus meeting the performance requirements for the NBI vacuum system and providing a basis for subsequent implementation of the NBI vacuum system upgrade using engineering.

In situ TEM studies of irradiation effects for materials improvement

1991 ◽  
Vol 49 ◽  
pp. 452-453
Author(s):  
Charles W. Allen
Keyword(s):  
Nuclear Reactor ◽  
Austenitic Stainless Steels ◽  
High Energy ◽  
Point Of View ◽  
In Situ Tem ◽  
Irradiation Effects ◽  
Tem Analysis ◽  
Radiation Induced ◽  
Analytical Tools

Irradiation effects studies employing TEMs as analytical tools have been conducted for almost as many years as materials people have done TEM, motivated largely by materials needs for nuclear reactor development. Such studies have focussed on the behavior both of nuclear fuels and of materials for other reactor components which are subjected to radiation-induced degradation. Especially in the 1950s and 60s, post-irradiation TEM analysis may have been coupled to in situ (in reactor or in pile) experiments (e.g., irradiation-induced creep experiments of austenitic stainless steels). Although necessary from a technological point of view, such experiments are difficult to instrument (measure strain dynamically, e.g.) and control (temperature, e.g.) and require months or even years to perform in a nuclear reactor or in a spallation neutron source. Consequently, methods were sought for simulation of neutroninduced radiation damage of materials, the simulations employing other forms of radiation; in the case of metals and alloys, high energy electrons and high energy ions.

Status of muon catalysis of nuclear fusion reactions

1990 ◽  
Vol 160 (8) ◽  
pp. 47-103 ◽  
Author(s):  
Leonid I. Men'shikov ◽  
L.N. Somov
Keyword(s):  
Nuclear Fusion ◽  
Fusion Reactions ◽  
Nuclear Fusion Reactions ◽  
Muon Catalysis

Proposed Solutions to Achieve Nuclear Fusion

Engevista ◽  
2017 ◽  
Vol 19 (5) ◽  
pp. 1496
Author(s):  
Relly Victoria Virgil Petrescu ◽  
Raffaella Aversa ◽  
Antonio Apicella ◽  
Florian Ion Petrescu
Keyword(s):  
Nuclear Reactor ◽  
Nuclear Reactions ◽  
Nuclear Fusion ◽  
Nuclear Fission ◽  
Light Nuclei ◽  
Fast Neutrons ◽  
Fusion Reactions ◽  
Nuclear Fusion Reactions ◽  
The Masses ◽  
Fusion Products

Despite research carried out around the world since the 1950s, no industrial application of fusion to energy production has yet succeeded, apart from nuclear weapons with the H-bomb, since this application does not aims at containing and controlling the reaction produced. There are, however, some other less mediated uses, such as neutron generators. The fusion of light nuclei releases enormous amounts of energy from the attraction between the nucleons due to the strong interaction (nuclear binding energy). Fusion it is with nuclear fission one of the two main types of nuclear reactions applied. The mass of the new atom obtained by the fusion is less than the sum of the masses of the two light atoms. In the process of fusion, part of the mass is transformed into energy in its simplest form: heat. This loss is explained by the Einstein known formula E=mc2. Unlike nuclear fission, the fusion products themselves (mainly helium 4) are not radioactive, but when the reaction is used to emit fast neutrons, they can transform the nuclei that capture them into isotopes that some of them can be radioactive. In order to be able to start and to be maintained with the success the nuclear fusion reactions, it is first necessary to know all this reactions very well. This means that it is necessary to know both the main reactions that may take place in a nuclear reactor and their sense and effects. The main aim is to choose and coupling the most convenient reactions, forcing by technical means for their production in the reactor. Taking into account that there are a multitude of possible variants, it is necessary to consider in advance the solutions that we consider them optimal. The paper takes into account both variants of nuclear fusion, and cold and hot. For each variant will be mentioned the minimum necessary specifications.

scholarly journals Foeniculum vulgare Essential Oils: Chemical Composition, Antioxidant and Antimicrobial Activities

2010 ◽  
Vol 5 (2) ◽  
pp. 1934578X1000500 ◽  
Author(s):  
Maria Graça Miguel ◽  
Cláudia Cruz ◽  
Leonor Faleiro ◽  
Mariana T. F. Simões ◽  
Ana Cristina Figueiredo ◽  
...  
Keyword(s):  
Essential Oils ◽  
Radical Scavenging ◽  
Antimicrobial Activities ◽  
Point Of View ◽  
Diffusion Method ◽  
Foeniculum Vulgare ◽  
Aerial Parts ◽  
Scavenging Capacity ◽  
Dpph Method ◽  
Main Components

The essential oils from Foeniculum vulgare commercial aerial parts and fruits were isolated by hydrodistillation, with different distillation times (30 min, 1 h, 2 h and 3 h), and analyzed by GC and GC-MS. The antioxidant ability was estimated using four distinct methods. Antibacterial activity was determined by the agar diffusion method. Remarkable differences, and worrying from the quality and safety point of view, were detected in the essential oils. trans-Anethole (31-36%), α-pinene (14-20%) and limonene (11-13%) were the main components of the essentials oil isolated from F. vulgare dried aerial parts, whereas methyl chavicol (= estragole) (79-88%) was dominant in the fruit oils. With the DPPH method the plant oils showed better antioxidant activity than the fruits oils. With the TBARS method and at higher concentrations, fennel essential oils showed a pro-oxidant activity. None of the oils showed a hydroxyl radical scavenging capacity >50%, but they showed an ability to inhibit 5-lipoxygenase. The essential oils showed a very low antimicrobial activity. In general, the essential oils isolated during 2 h were as effective, from the biological activity point of view, as those isolated during 3 h.

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