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Results for “THERMONUCLEAR POWER PLANTS”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 19 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2018

A Realistic, Gradual and Economical Approach to Fusion Power

This article describes, in broad outline, a nuclear power plant that generates power by means of repetitive, low-yield explosions in an underground chamber. Such a plant can be built in the near future by using modest extensions of existing technology, and it could be economically competitive if certain parts of the cost are controlled. This is in contrast to magnetic and inertial confinement fusion, of which the technical and economic feasibility will remain highly uncertain for the foreseeable future. Technical improvements of the envisioned plant can be introduced gradually with corresponding reductions in cost of power production. With advancing technology, an increasingly larger fraction of the power can be extracted from fusion reactions, thus providing a smooth transition to a fusion-based economy. Eventually, pure (inertial) fusion schemes could be incorporated into the power plant in a natural way, thereby shortening the time required to achieve large-scale use of fusion power--possibly by decades. This article considers both the technical aspects of this route to fusion power and the relevant issues of public policy.

45 MILITARY TECHNOLOGY, WEAPONRY, AND NATIONAL DEF↗
DOE OSTI2016

Cryogenic hydrogen fuel for controlled inertial confinement fusion (formation of reactor-scale cryogenic targets)

In inertial fusion energy research, considerable attention has recently been focused on low-cost fabrication of a large number of targets by developing a specialized layering module of repeatable operation. The targets must be free-standing, or unmounted. Therefore, the development of a target factory for inertial confinement fusion (ICF) is based on methods that can ensure a cost-effective target production with high repeatability. Minimization of the amount of tritium (i.e., minimization of time and space at all production stages) is a necessary condition as well. Additionally, the cryogenic hydrogen fuel inside the targets must have a structure (ultrafine layers—the grain size should be scaled back to the nanometer range) that supports the fuel layer survivability under target injection and transport through the reactor chamber. To meet the above requirements, significant progress has been made at the Lebedev Physical Institute (LPI) in the technology developed on the basis of rapid fuel layering inside moving free-standing targets (FST), also referred to as the FST layering method. Owing to the research carried out at LPI, unique experience has been gained in the development of the FST-layering module for target fabrication with an ultrafine fuel layer, including a reactor- scale target design. This experience can be used for the development of the next-generation FST-layering module for construction of a prototype of a target factory for power laser facilities and inertial fusion power plants.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2016

Ion collector design for an energy recovery test proposal with the negative ion source NIO1

Commercial viability of thermonuclear fusion power plants depends also on minimizing the recirculation power used to operate the reactor. The neutral beam injector (NBI) remains one of the most important method for plasma heating and control. For the future fusion power plant project DEMO, a NBI wall plug efficiency at least of 0.45 is required, while efficiency of present NBI project is about 0.25. The D{sup −} beam from a negative ion source is partially neutralized by a gas cell, which leaves more than 40% of energy in residual beams (D{sup −} and D{sup +}), so that an ion beam energy recovery system can significantly contribute to optimize efficiency. Recently, the test negative ion source NIO1 (60 keV, 9 beamlets with 15 mA H{sup −} each) has been designed and built at RFX (Padua) for negative ion production efficiency and the beam quality optimization. In this paper, a study proposal to use the NIO1 source also for a beam energy recovery test experiment is presented and a preliminary design of a negative ion beam collector with simulations of beam energy recovery is discussed.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2018

The role of tungsten phases formation during tungsten metal powder consolidation by FAST: Implications for high-temperature applications

Highlights: • Lowering the sintering temperature of W to 2173 K by using FAST. • Application of electron microscopy for microstructure characterisation. • W{sub 2}C shell formation due to C difussion from graphite tooling. • Identification of co-formed secondary phase, WO{sub 2}. • Influence of WO{sub 2} on high-thermal applications. - Abstract: Tungsten is a candidate material for the demonstration fusion power plant DEMO. To ensure high density and structural stability, Field-Assisted Sintering Technique (FAST) is proposed as a consolidation method. This study discusses the formation of phases during sintering of tungsten by the FAST. Scanning electron microscopy, X-ray diffraction and transmission electron microscopy were used to evaluate the microstructure in tungsten-based materials. The results of microscopic examinations revealed the in-situ formation of tungsten oxide and a formation of tungsten carbide shell around tungsten core. Tungsten carbide-rich shell is formed due to the carbon diffusion from the graphite die used in the FAST into tungsten at high temperatures. In contrast to easy removal of tungsten carbide shell by mechanical grinding, the formation of tungsten oxide in the W-matrix can influence the performance of such material when used as plasma-facing material in the fusion reactor. High-temperature experiments at 1873 K showed that tungsten-oxide phase starts to decompose, which results in material degradation and formation of voids and surface blisters.

36 MATERIALS SCIENCE↗
DOE OSTI2017

Thermonuclear Power Engineering: 60 Years of Research. What Comes Next?

This paper summarizes results of more than half a century of research of high-temperature plasmas heated to a temperature of more than 100 million degrees (10{sup 4} eV) and magnetically insulated from the walls. The energy of light-element fusion сan be used for electric power generation or as a source of fissionable fuel production (development of a fusion neutron source—FNS). The main results of studies of tokamak plasmas which were obtained in the Soviet Union with the greatest degree of thermal plasma isolation among all other types of devices are presented. As a result, research programs of other countries were redirected to tokamaks. Later, on the basis of the analysis of numerous experiments, the international fusion community gradually came to an opinion that it is possible to build a tokamak (ITER) with Q > 1 (where Q is the ratio of the fusion power to the external power injected into the plasma). The ITER program objective is to achieve Q = 1–10 for a discharge time of up to 1000 s. The implementation of this goal does not solve the problem of a steadystate operation. The solution to this problem is a reliable first wall and current generation. This is a task of the next fusion power plant construction stage, called DEMO. Comparison of DEMO and FNS parameters shows that, at this development stage, the operating parameters and conditions of these devices are identical.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2018

Towards Zero Manual Intervention - 18358

As humanity reaches further we become more aware of our biological limitations. For some activities we are physically too big or too small, too strong or too weak or might be damaged in some way if we intervene directly. Whilst this is not a new phenomena, we are now starting to see the emergence of aspirations that demand a different approach because people cannot physically intervene. The example used within this paper is a fusion power plant which generates highly energetic 14.1 MeV neutrons that elevate radiation levels to prohibitive levels which preclude human access. For statutory and/or commercial reasons, inspection and maintenance is necessary and/or unavoidable in high risk or 'challenging environments'. These challenging environments occur in nuclear, space, petrochemicals and other complex industrial spaces. They also occur in adjacent markets where solutions must also achieve levels of usability, reliability and safety at an acceptable cost before widespread adoption is achieved. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2015

Enhanced sensitivity of Raman spectroscopy for tritium gas analysis using a metal-lined hollow glass fiber

The precise compositional analysis of tritium-containing gases is of high interest for tritium accountancy in future fusion power plants. Raman spectroscopy provides a fast and contact-free gas analysis procedure with high precision, thus being an advantageous tool for the named purpose. In this paper, it is shown that the sensitivity achieved with conventional Raman systems (in 90 degrees or forward/backward configurations) can be enhanced by at least one order of magnitude by using a metal-lined hollow glass fiber as the Raman cell. This leads to the ability of detecting low partial pressures of tritium within short measurement intervals (< 0.5 mbar in < 0.5 s) opening the way for real-time applications.

07 ISOTOPE AND RADIATION SOURCES↗
DOE OSTI2017

Towards a Remote Handling Toolkit for Fusion: Lessons Learnt and Future Challenges - 17360

It is increasingly recognised within the fusion research community that the next generation of remote maintenance solutions will be a 'device defining driver' for a future fusion power plant. The unique Remote Handling Systems that operates at JET, EUROfusion's research reactor that is operated by the UKAEA at Culham, Oxfordshire, remains the archetype for future designs. At ITER, the international fusion research experiment being constructed in the South of France, many $100's millions will be invested in supplying and then operating remote handling solutions. This paper will provide a brief history of the JET Remote Handling System in recent campaigns and will present initial results of the ITER remote operated cutting and welding trials. Finally, the paper will comment on reasons for establishing RACE, the UKAEA's centre for Remote Applications in Challenging Environments and the task of integrating new robotics including autonomous vehicles, snake-like manipulators and autonomous remote maintenance systems into the design of a future fusion reactor. (authors)

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2015

Tritium Laboratory Karlsruhe: administrative and technical framework for isotope laboratory operation

Originally licensed in 1993 the Tritium Laboratory Karlsruhe (TLK) is a unique pilot scale isotope laboratory focused on tritium handling and processing to conduct a variety of scientific experiments and development tasks in view of future fusion power plants. TLK currently operates 15 glove boxes of 125 m{sup 3} total volume in an experimental hall measuring nearly 1500 m{sup 2}. The tritium infrastructure, comprising of the tritium storage system, the tritium transfer system and the isotope separation system, is integrated into TLK as a closed loop system to supply tritium to the experiments. Having a license for handling of up to 40 g of tritium and a closed tritium processing loop, TLK is a unique institute in non-military tritium research. In order to fulfil all requirements regarding the license, a framework of regulations is applied as a basis for the operation of TLK, as well as the setup of new experiments and the design of components. This paper will give an overview on the framework of operation in view of licensing issues, as well as administrative and technical regulations mandatory to legally and reliably operate an isotope laboratory of this scale.

07 ISOTOPE AND RADIATION SOURCES↗
DOE OSTI2021

A polar direct drive liquid deuterium–tritium wetted foam target concept for inertial confinement fusion

We propose a new approach to inertial confinement fusion (ICF) that could potentially lead to ignition and propagating thermonuclear burn at the National Ignition Facility (NIF). The proposal is based upon a combination of two concepts, referred to as polar direct drive and liquid deuterium–tritium wetted foam capsules. With this new concept, 2D radiation hydrodynamic simulations indicate that ICF ignition and propagating thermonuclear burn are possible with the laser power and energy capabilities available today on the NIF.

3D printing↗
DOE OSTI2015

First calibration measurements of an FTIR absorption spectroscopy system for liquid hydrogen isotopologues for the isotope separation system of fusion power plants

Fusion facilities like ITER and DEMO will circulate huge amounts of deuterium and tritium in their fuel cycle with an estimated throughput of kg per hour. One important capability of these fuel cycles is to separate the hydrogen isotopologues (H{sub 2}, D{sub 2}, T{sub 2}, HD, HT, DT). For this purpose the Isotope Separation System (ISS), using cryogenic distillation, as part of the Tritium Enrichment Test Assembly (TRENTA) is under development at Tritium Laboratory Karlsruhe. Fourier transform infrared absorption spectroscopy (FTIR) has been selected to prove its capability for online monitoring of the tritium concentration in the liquid phase at the bottom of the distillation column of the ISS. The actual research-development work is focusing on the calibration of such a system. Two major issues are the identification of appropriate absorption lines and their dependence on the isotopic concentrations and composition. For this purpose the Tritium Absorption IR spectroscopy experiment has been set up as an extension of TRENTA. For calibration a Raman spectroscopy system is used. First measurements, with equilibrated mixtures of H{sub 2}, D{sub 2} and HD demonstrate that FTIR can be used for quantitative analysis of liquid hydro-gen isotopologues and reveal a nonlinear dependence of the integrated absorbance from the D{sub 2} concentration in the second vibrational branch of D{sub 2} FTIR spectra. (authors)

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2015

Evaluation of tritium release properties of advanced tritium breeders

Demonstration power plant (DEMO) fusion reactors require advanced tritium breeders with high thermal stability. Lithium titanate (Li{sub 2}TiO{sub 3}) advanced tritium breeders with excess Li (Li{sub 2+x}TiO{sub 3+y}) are stable in a reducing atmosphere at high temperatures. Although the tritium release properties of tritium breeders are documented in databases for DEMO blanket design, no in situ examination under fusion neutron (DT neutron) irradiation has been performed. In this study, a preliminary examination of the tritium release properties of advanced tritium breeders was performed, and DT neutron irradiation experiments were performed at the fusion neutronics source (FNS) facility in JAEA. Considering the tritium release characteristics, the optimum grain size after sintering is <5 μm. From the results of the optimization of granulation conditions, prototype Li{sub 2+x}TiO{sub 3+y} pebbles with optimum grain size (<5 μm) were successfully fabricated. The Li{sub 2+x}TiO{sub 3+y} pebbles exhibited good tritium release properties similar to the Li{sub 2}TiO{sub 3} pebbles. In particular, the released amount of HT gas for easier tritium handling was higher than that of HTO water. (authors)

07 ISOTOPE AND RADIATION SOURCES↗
DOE OSTI2016

Mechanical and Thermal Properties of Irradiated SiC/SiC Composites: Bridge Continuum Models With Atomic-level Simulations

Due to their excellent high-temperature fracture, creep, corrosion, and thermal shock resistance in addition to their high thermo-chemical stability, reduced activation, and low radiation- induced after heat, silicon carbide-fiber/silicon carbide-matrix (SiC/SiC) composites are being developed as structural materials for first wall and breeder blanket applications in advanced fusion power plants. In such applications these materials will be subjected to a high heat flux that imposes extremely stringent requirements on the minimum thermal conductivity needed. Also, SiC offers a number of potential applications for both electron devices and structural components as an inert matrix for the transmutation of plutonium and as cladding material for gas-cooled fission reactor. There has been a rapid growth of activity in the experimental study and the modeling of energetic-beam interactions, such as those encountered in ion-beam processing or in irradiation environments, on the structure and properties of SiC. During the last decade, understanding the basics of ion-solid interaction and irradiation damage has led to significant developments in state-of-the-art atomic-level, meso-scale simulations and continuum models of mechanical and thermal property prediction, and these different scales studies have dramatically advanced the understanding of defect and defect processes in a number of materials, ranging from metals to semiconductors to insulators. Recent progress in multi-scale simulations of fundamental ion-solid interactions, defect generation and defect evolution in SiC, as well as its property degradation under irradiation, is reviewed, which will provide significant insights into the radiation resistance behavior of SiC and SiC/SiC composites. (authors)

36 MATERIALS SCIENCE↗
DOE OSTI2016

Systematic cavity design approach for a multi-frequency gyrotron for DEMO and study of its RF behavior

High frequency (>230 GHz) megawatt-class gyrotrons are planned as RF sources for electron cyclotron resonance heating and current drive in DEMOnstration fusion power plants (DEMOs). In this paper, for the first time, a feasibility study of a 236 GHz DEMO gyrotron is presented by considering all relevant design goals and the possible technical limitations. A mode-selection procedure is proposed in order to satisfy the multi-frequency and frequency-step tunability requirements. An effective systematic design approach for the optimal design of a gradually tapered cavity is presented. The RF-behavior of the proposed cavity is verified rigorously, supporting 920 kW of stable output power with an interaction efficiency of 36% including the considerations of realistic beam parameters.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2024

Frontier system-on-chip (SoC) technology for microwave diagnostics (invited)

The next generation of fusion reactors, exemplified by projects such as the Demonstration Power Plant following the International Thermonuclear Experimental Reactor, faces the monumental challenge of proving the viability of generating electricity through thermonuclear fusion. This pursuit introduces heightened complexities in diagnostic methodologies, particularly in microwave-based diagnostics. The increased neutron fluence necessitates significant reductions in vessel penetrations and the elimination of internal diagnostics, posing substantial challenges. SoC technology offers a promising solution by enabling the miniaturization, modularization, integration, and enhancing the reliability of microwave systems. After seven years of research, our team successfully pioneered the V- and W-band system-on-chip approach, leading to the development of active transmitters and passive receiver modules applied in practical settings, notably within the DIII-D tokamak project. Arrays of these modules have supported microwave imaging diagnostics. New physics measurement results from the Electron Cyclotron Emission Imaging system on DIII-D provide compelling evidence of improved diagnostics following the adoption of SoC technology. Furthermore, we achieved a breakthrough in developing an F-band SoC, advancing higher frequency capabilities for fusion devices. These achievements represent a significant leap forward in fusion diagnostic technology, marking substantial progress toward establishing reliable and efficient plasma diagnostics for future fusion reactors.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2015

The use of water in a fusion power core

Water has both advantages and disadvantages as a coolant in conceptual designs of future fusion power plants. In the United States, water has not been chosen as a fusion power core coolant for decades. Researchers in other countries continue to adopt water in their designs, in some cases as the leading or sole candidate. In this article, we summarize the technical challenges resulting from the choice of water coolant and the differences in approach and assumptions that lead to different design decisions amongst researchers in this field.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2016

Magnet Design Considerations for Fusion Nuclear Science Facility

The Fusion Nuclear Science Facility (FNSF) is a nuclear confinement facility that provides a fusion environment with components of the reactor integrated together to bridge the technical gaps of burning plasma and nuclear science between the International Thermonuclear Experimental Reactor (ITER) and the demonstration power plant (DEMO). Compared with ITER, the FNSF is smaller in size but generates much higher magnetic field, i.e., 30 times higher neutron fluence with three orders of magnitude longer plasma operation at higher operating temperatures for structures surrounding the plasma. Input parameters to the magnet design from system code analysis include magnetic field of 7.5 T at the plasma center with a plasma major radius of 4.8 m and a minor radius of 1.2 m and a peak field of 15.5 T on the toroidal field (TF) coils for the FNSF. Both low-temperature superconductors (LTS) and high-temperature superconductors (HTS) are considered for the FNSF magnet design based on the state-of-the-art fusion magnet technology. The higher magnetic field can be achieved by using the high-performance ternary restacked-rod process Nb3Sn strands for TF magnets. The circular cable-in-conduit conductor (CICC) design similar to ITER magnets and a high-aspect-ratio rectangular CICC design are evaluated for FNSF magnets, but low-activation-jacket materials may need to be selected. The conductor design concept and TF coil winding pack composition and dimension based on the horizontal maintenance schemes are discussed. Neutron radiation limits for the LTS and HTS superconductors and electrical insulation materials are also reviewed based on the available materials previously tested. The material radiation limits for FNSF magnets are defined as part of the conceptual design studies for FNSF magnets.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗