The Experts below are selected from a list of 213 Experts worldwide ranked by ideXlab platform
U Fantz - One of the best experts on this subject based on the ideXlab platform.
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rami evaluation of the beam source for the demo neutral beam injectors
Fusion Engineering and Design, 2020Co-Authors: P Agostinetti, U Fantz, T Franke, C Hopf, N Mantel, M Q TraAbstract:Abstract DEMO is a first-of-a-kind DEMOnstration fusion power plant [1] , [2] and is intended to follow the ITER experimental reactor. The main goal of DEMO will be to demonstrate the possibility to produce electric energy for the grid from the fusion reaction early in the second half of the century. The injection of high energy neutral (1 MeV) particle beams is one of the main tools to heat the plasma up to fusion conditions, control the plasma burn phase and ramp the plasma down. Within the EUROfusion Framework a conceptual design of the Neutral Beam Injector (NBI) for the DEMO fusion reactor is currently being developed. Thereby, Reliability, Availability, Maintainability and Inspectability (RAMI) have to be taken into consideration for the conceptual design of the DEMO NBI, together with the exploitation of the currently available return of experience from the ITER NBIs. Comparing the failure risk of two different source concepts due to the considered failure modes has allowed for further design developments aiming at exploiting the advantages of the modular approach while minimizing its drawbacks.
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investigations on cs free alternatives for negative ion formation in a low pressure hydrogen discharge at ion source relevant parameters
Plasma Physics and Controlled Fusion, 2017Co-Authors: U Kurutz, R Friedl, U FantzAbstract:Caesium (Cs) is applied in high power negative hydrogen ion sources to reduce a converter surface's work function and thus enabling an efficient negative ion surface formation. Inherent drawbacks with the usage of this reactive alkali metal motivate the search for Cs-free alternative materials for neutral beam injection systems in fusion research. In view of a future DEMOnstration power plant, a suitable material should provide a high negative ion formation efficiency and comply with the RAMI issues of the system: reliability, availability, maintainability, Inspectability. Promising candidates, like low work function materials (molybdenum doped with lanthanum (MoLa) and LaB6), as well as different non-doped and boron-doped diamond samples were investigated in this context at identical and ion source relevant parameters at the laboratory experiment HOMER. Negative ion densities were measured above the samples by means of laser photodetachment and compared with two reference cases: pure negative ion volume formation with negative ion densities of about and the effect of H− surface production using an in situ caesiated stainless steel sample which yields 2.5 times higher densities. Compared to pure volume production, none of the diamond samples did exhibit a measurable increase in H− densities, while showing clear indications of plasma-induced erosion. In contrast, both MoLa and LaB6 produced systematically higher densities (MoLa: ×1.60; LaB6: ×1.43). The difference to caesiation can be attributed to the higher work functions of MoLa and LaB6 which are expected to be about 3 eV for both compared to 2.1 eV of a caesiated surface.
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conceptual design of the demo neutral beam injectors main developments and r d achievements
Nuclear Fusion, 2017Co-Authors: P Sonato, P Agostinetti, T Bolzonella, F Cismondi, U Fantz, A Fassina, T Franke, I Furno, C Hopf, I JenkinsAbstract:The objectives of the nuclear fusion power plant DEMO, to be built after the ITER experimental reactor, are usually understood to lie somewhere between those of ITER and a 'first of a kind' commercial plant. Hence, in DEMO the issues related to efficiency and RAMI (reliability, availability, maintainability and Inspectability) are among the most important drivers for the design, as the cost of the electricity produced by this power plant will strongly depend on these aspects. In the framework of the EUROfusion Work Package Heating and Current Drive within the Power Plant Physics and Development activities, a conceptual design of the neutral beam injector (NBI) for the DEMO fusion reactor has been developed by Consorzio RFX in collaboration with other European research institutes. In order to improve efficiency and RAMI aspects, several innovative solutions have been introduced in comparison to the ITER NBI, mainly regarding the beam source, neutralizer and vacuum pumping systems.
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conceptual design of the beam source for the demo neutral beam injectors
New Journal of Physics, 2016Co-Authors: P Sonato, P Agostinetti, U Fantz, T Franke, I Furno, A Simonin, M Q TranAbstract:DEMO (DEMOnstration Fusion Power Plant) is a proposed nuclear fusion power plant that is intended to follow the ITER experimental reactor. The main goal of DEMO will be to demonstrate the possibility to produce electric energy from the fusion reaction. The injection of high energy neutral beams is one of the main tools to heat the plasma up to fusion conditions. A conceptual design of the Neutral Beam Injector (NBI) for the DEMO fusion reactor, is currently being developed by Consorzio RFX in collaboration with other European research institutes. High efficiency and low recirculating power, which are fundamental requirements for the success of DEMO, have been taken into special consideration for the DEMO NBI. Moreover, particular attention has been paid to the issues related to reliability, availability, maintainability and Inspectability. A conceptual design of the beam source for the DEMO NBI is here presented featuring 20 sub-sources (two adjacent columns of 10 sub-sources each), following a modular design concept, with each sub-source featuring its radio frequency driver, capable of increasing the reliability and availability of the DEMO NBI. Copper grids with increasing size of the apertures have been adopted in the accelerator, with three main layouts of the apertures (circular apertures, slotted apertures and frame-like apertures for each sub-source). This design, permitting to significantly decrease the stripping losses in the accelerator without spoiling the beam optics, has been investigated with a self-consistent model able to study at the same time the magnetic field, the electrostatic field and the trajectory of the negative ions. Moreover, the status on the R&D carried out in Europe on the ion sources is presented.
Luigi Lazzeri - One of the best experts on this subject based on the ideXlab platform.
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Fatigue Crack Growth in Pin Loaded Cold-Worked Holes
ICAF 2019 – Structural Integrity in the Age of Additive Manufacturing, 2020Co-Authors: Luisa Boni, Daniele Fanteria, Domenico Furfari, Luigi LazzeriAbstract:An experimental program has been carried out for the evaluation of the influence of the split sleeve expansion process on the fatigue crack growth in 2024-T351 aluminium alloy specimens. In previous ICAF Symposia, some information has been already given about the first part of the experimental activity (Helsinki 2015) and about the development of a numerical analysis method (Nagoya 2017). Both such preliminary papers referred to open hole specimens, tested under Constant Amplitude loading, while recently a pin loaded hole configuration has been evaluated. The non-Inspectability of the configuration required some particular experimental effort, in order to collect test results in terms of crack growth as a function of number of cycles. To this end, a marker load technique was adopted: a block of high R ratio cycles (R = 0.9) was inserted in the R = 0.1 sequence, with the aim of obtaining information about the crack front evolution at different number of cycles. Due to the three-dimensionality of the residual stress field, which is of lower intensity at the face of mandrel entrance, a 1 mm radius quarter-circular notch was inserted by means of EDM on the mandrel entry side face. Moreover, it was necessary to include also mechanically milled notches, of similar dimensions. The results show a rather regular front evolution, and have provided important material for the development of accurate numerical methods, based on the evaluation of the residual stress field and on the subsequent modification of the stress intensity factor distribution along the corner crack front. The numerical analysis methodology is a specialization of the technique, already presented in the Nagoya Symposium, to the problem of single or double corner crack in a pin loaded hole. In particular, the strong three-dimensionality of the stress field poses a challenge to the block-by-block propagation analysis.
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fatigue crack growth in pin loaded cold worked holes
International Committee on Aeronautical Fatigue, 2019Co-Authors: Luisa Boni, Daniele Fanteria, Domenico Furfari, Luigi LazzeriAbstract:An experimental program has been carried out for the evaluation of the influence of the split sleeve expansion process on the fatigue crack growth in 2024-T351 aluminium alloy specimens. In previous ICAF Symposia, some information has been already given about the first part of the experimental activity (Helsinki 2015) and about the development of a numerical analysis method (Nagoya 2017). Both such preliminary papers referred to open hole specimens, tested under Constant Amplitude loading, while recently a pin loaded hole configuration has been evaluated. The non-Inspectability of the configuration required some particular experimental effort, in order to collect test results in terms of crack growth as a function of number of cycles. To this end, a marker load technique was adopted: a block of high R ratio cycles (R = 0.9) was inserted in the R = 0.1 sequence, with the aim of obtaining information about the crack front evolution at different number of cycles.
P Sonato - One of the best experts on this subject based on the ideXlab platform.
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conceptual design of the demo neutral beam injectors main developments and r d achievements
Nuclear Fusion, 2017Co-Authors: P Sonato, P Agostinetti, T Bolzonella, F Cismondi, U Fantz, A Fassina, T Franke, I Furno, C Hopf, I JenkinsAbstract:The objectives of the nuclear fusion power plant DEMO, to be built after the ITER experimental reactor, are usually understood to lie somewhere between those of ITER and a 'first of a kind' commercial plant. Hence, in DEMO the issues related to efficiency and RAMI (reliability, availability, maintainability and Inspectability) are among the most important drivers for the design, as the cost of the electricity produced by this power plant will strongly depend on these aspects. In the framework of the EUROfusion Work Package Heating and Current Drive within the Power Plant Physics and Development activities, a conceptual design of the neutral beam injector (NBI) for the DEMO fusion reactor has been developed by Consorzio RFX in collaboration with other European research institutes. In order to improve efficiency and RAMI aspects, several innovative solutions have been introduced in comparison to the ITER NBI, mainly regarding the beam source, neutralizer and vacuum pumping systems.
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conceptual design of the beam source for the demo neutral beam injectors
New Journal of Physics, 2016Co-Authors: P Sonato, P Agostinetti, U Fantz, T Franke, I Furno, A Simonin, M Q TranAbstract:DEMO (DEMOnstration Fusion Power Plant) is a proposed nuclear fusion power plant that is intended to follow the ITER experimental reactor. The main goal of DEMO will be to demonstrate the possibility to produce electric energy from the fusion reaction. The injection of high energy neutral beams is one of the main tools to heat the plasma up to fusion conditions. A conceptual design of the Neutral Beam Injector (NBI) for the DEMO fusion reactor, is currently being developed by Consorzio RFX in collaboration with other European research institutes. High efficiency and low recirculating power, which are fundamental requirements for the success of DEMO, have been taken into special consideration for the DEMO NBI. Moreover, particular attention has been paid to the issues related to reliability, availability, maintainability and Inspectability. A conceptual design of the beam source for the DEMO NBI is here presented featuring 20 sub-sources (two adjacent columns of 10 sub-sources each), following a modular design concept, with each sub-source featuring its radio frequency driver, capable of increasing the reliability and availability of the DEMO NBI. Copper grids with increasing size of the apertures have been adopted in the accelerator, with three main layouts of the apertures (circular apertures, slotted apertures and frame-like apertures for each sub-source). This design, permitting to significantly decrease the stripping losses in the accelerator without spoiling the beam optics, has been investigated with a self-consistent model able to study at the same time the magnetic field, the electrostatic field and the trajectory of the negative ions. Moreover, the status on the R&D carried out in Europe on the ion sources is presented.
P Agostinetti - One of the best experts on this subject based on the ideXlab platform.
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rami evaluation of the beam source for the demo neutral beam injectors
Fusion Engineering and Design, 2020Co-Authors: P Agostinetti, U Fantz, T Franke, C Hopf, N Mantel, M Q TraAbstract:Abstract DEMO is a first-of-a-kind DEMOnstration fusion power plant [1] , [2] and is intended to follow the ITER experimental reactor. The main goal of DEMO will be to demonstrate the possibility to produce electric energy for the grid from the fusion reaction early in the second half of the century. The injection of high energy neutral (1 MeV) particle beams is one of the main tools to heat the plasma up to fusion conditions, control the plasma burn phase and ramp the plasma down. Within the EUROfusion Framework a conceptual design of the Neutral Beam Injector (NBI) for the DEMO fusion reactor is currently being developed. Thereby, Reliability, Availability, Maintainability and Inspectability (RAMI) have to be taken into consideration for the conceptual design of the DEMO NBI, together with the exploitation of the currently available return of experience from the ITER NBIs. Comparing the failure risk of two different source concepts due to the considered failure modes has allowed for further design developments aiming at exploiting the advantages of the modular approach while minimizing its drawbacks.
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conceptual design of the demo neutral beam injectors main developments and r d achievements
Nuclear Fusion, 2017Co-Authors: P Sonato, P Agostinetti, T Bolzonella, F Cismondi, U Fantz, A Fassina, T Franke, I Furno, C Hopf, I JenkinsAbstract:The objectives of the nuclear fusion power plant DEMO, to be built after the ITER experimental reactor, are usually understood to lie somewhere between those of ITER and a 'first of a kind' commercial plant. Hence, in DEMO the issues related to efficiency and RAMI (reliability, availability, maintainability and Inspectability) are among the most important drivers for the design, as the cost of the electricity produced by this power plant will strongly depend on these aspects. In the framework of the EUROfusion Work Package Heating and Current Drive within the Power Plant Physics and Development activities, a conceptual design of the neutral beam injector (NBI) for the DEMO fusion reactor has been developed by Consorzio RFX in collaboration with other European research institutes. In order to improve efficiency and RAMI aspects, several innovative solutions have been introduced in comparison to the ITER NBI, mainly regarding the beam source, neutralizer and vacuum pumping systems.
-
conceptual design of the beam source for the demo neutral beam injectors
New Journal of Physics, 2016Co-Authors: P Sonato, P Agostinetti, U Fantz, T Franke, I Furno, A Simonin, M Q TranAbstract:DEMO (DEMOnstration Fusion Power Plant) is a proposed nuclear fusion power plant that is intended to follow the ITER experimental reactor. The main goal of DEMO will be to demonstrate the possibility to produce electric energy from the fusion reaction. The injection of high energy neutral beams is one of the main tools to heat the plasma up to fusion conditions. A conceptual design of the Neutral Beam Injector (NBI) for the DEMO fusion reactor, is currently being developed by Consorzio RFX in collaboration with other European research institutes. High efficiency and low recirculating power, which are fundamental requirements for the success of DEMO, have been taken into special consideration for the DEMO NBI. Moreover, particular attention has been paid to the issues related to reliability, availability, maintainability and Inspectability. A conceptual design of the beam source for the DEMO NBI is here presented featuring 20 sub-sources (two adjacent columns of 10 sub-sources each), following a modular design concept, with each sub-source featuring its radio frequency driver, capable of increasing the reliability and availability of the DEMO NBI. Copper grids with increasing size of the apertures have been adopted in the accelerator, with three main layouts of the apertures (circular apertures, slotted apertures and frame-like apertures for each sub-source). This design, permitting to significantly decrease the stripping losses in the accelerator without spoiling the beam optics, has been investigated with a self-consistent model able to study at the same time the magnetic field, the electrostatic field and the trajectory of the negative ions. Moreover, the status on the R&D carried out in Europe on the ion sources is presented.
Luisa Boni - One of the best experts on this subject based on the ideXlab platform.
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Fatigue Crack Growth in Pin Loaded Cold-Worked Holes
ICAF 2019 – Structural Integrity in the Age of Additive Manufacturing, 2020Co-Authors: Luisa Boni, Daniele Fanteria, Domenico Furfari, Luigi LazzeriAbstract:An experimental program has been carried out for the evaluation of the influence of the split sleeve expansion process on the fatigue crack growth in 2024-T351 aluminium alloy specimens. In previous ICAF Symposia, some information has been already given about the first part of the experimental activity (Helsinki 2015) and about the development of a numerical analysis method (Nagoya 2017). Both such preliminary papers referred to open hole specimens, tested under Constant Amplitude loading, while recently a pin loaded hole configuration has been evaluated. The non-Inspectability of the configuration required some particular experimental effort, in order to collect test results in terms of crack growth as a function of number of cycles. To this end, a marker load technique was adopted: a block of high R ratio cycles (R = 0.9) was inserted in the R = 0.1 sequence, with the aim of obtaining information about the crack front evolution at different number of cycles. Due to the three-dimensionality of the residual stress field, which is of lower intensity at the face of mandrel entrance, a 1 mm radius quarter-circular notch was inserted by means of EDM on the mandrel entry side face. Moreover, it was necessary to include also mechanically milled notches, of similar dimensions. The results show a rather regular front evolution, and have provided important material for the development of accurate numerical methods, based on the evaluation of the residual stress field and on the subsequent modification of the stress intensity factor distribution along the corner crack front. The numerical analysis methodology is a specialization of the technique, already presented in the Nagoya Symposium, to the problem of single or double corner crack in a pin loaded hole. In particular, the strong three-dimensionality of the stress field poses a challenge to the block-by-block propagation analysis.
-
fatigue crack growth in pin loaded cold worked holes
International Committee on Aeronautical Fatigue, 2019Co-Authors: Luisa Boni, Daniele Fanteria, Domenico Furfari, Luigi LazzeriAbstract:An experimental program has been carried out for the evaluation of the influence of the split sleeve expansion process on the fatigue crack growth in 2024-T351 aluminium alloy specimens. In previous ICAF Symposia, some information has been already given about the first part of the experimental activity (Helsinki 2015) and about the development of a numerical analysis method (Nagoya 2017). Both such preliminary papers referred to open hole specimens, tested under Constant Amplitude loading, while recently a pin loaded hole configuration has been evaluated. The non-Inspectability of the configuration required some particular experimental effort, in order to collect test results in terms of crack growth as a function of number of cycles. To this end, a marker load technique was adopted: a block of high R ratio cycles (R = 0.9) was inserted in the R = 0.1 sequence, with the aim of obtaining information about the crack front evolution at different number of cycles.