| 1. |
- Abel, I, et al.
(författare)
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Overview of the JET results with the ITER-like wall
- 2013
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Ingår i: Nuclear Fusion. - : IOP Publishing. - 1741-4326 .- 0029-5515. ; 53:10, s. 104002-
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Tidskriftsartikel (refereegranskat)abstract
- Following the completion in May 2011 of the shutdown for the installation of the beryllium wall and the tungsten divertor, the first set of JET campaigns have addressed the investigation of the retention properties and the development of operational scenarios with the new plasma-facing materials. The large reduction in the carbon content (more than a factor ten) led to a much lower Z(eff) (1.2-1.4) during L- and H-mode plasmas, and radiation during the burn-through phase of the plasma initiation with the consequence that breakdown failures are almost absent. Gas balance experiments have shown that the fuel retention rate with the new wall is substantially reduced with respect to the C wall. The re-establishment of the baseline H-mode and hybrid scenarios compatible with the new wall has required an optimization of the control of metallic impurity sources and heat loads. Stable type-I ELMy H-mode regimes with H-98,H-y2 close to 1 and beta(N) similar to 1.6 have been achieved using gas injection. ELM frequency is a key factor for the control of the metallic impurity accumulation. Pedestal temperatures tend to be lower with the new wall, leading to reduced confinement, but nitrogen seeding restores high pedestal temperatures and confinement. Compared with the carbon wall, major disruptions with the new wall show a lower radiated power and a slower current quench. The higher heat loads on Be wall plasma-facing components due to lower radiation made the routine use of massive gas injection for disruption mitigation essential.
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| 2. |
- Romanelli, F, et al.
(författare)
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Overview of the JET results
- 2011
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Ingår i: Nuclear Fusion. - : IOP Publishing. - 1741-4326 .- 0029-5515. ; 51:9
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Tidskriftsartikel (refereegranskat)abstract
- Since the last IAEA Conference JET has been in operation for one year with a programmatic focus on the qualification of ITER operating scenarios, the consolidation of ITER design choices and preparation for plasma operation with the ITER-like wall presently being installed in JET. Good progress has been achieved, including stationary ELMy H-mode operation at 4.5 MA. The high confinement hybrid scenario has been extended to high triangularity, lower ρ*and to pulse lengths comparable to the resistive time. The steady-state scenario has also been extended to lower ρ*and ν*and optimized to simultaneously achieve, under stationary conditions, ITER-like values of all other relevant normalized parameters. A dedicated helium campaign has allowed key aspects of plasma control and H-mode operation for the ITER non-activated phase to be evaluated. Effective sawtooth control by fast ions has been demonstrated with3He minority ICRH, a scenario with negligible minority current drive. Edge localized mode (ELM) control studies using external n = 1 and n = 2 perturbation fields have found a resonance effect in ELM frequency for specific q95values. Complete ELM suppression has, however, not been observed, even with an edge Chirikov parameter larger than 1. Pellet ELM pacing has been demonstrated and the minimum pellet size needed to trigger an ELM has been estimated. For both natural and mitigated ELMs a broadening of the divertor ELM-wetted area with increasing ELM size has been found. In disruption studies with massive gas injection up to 50% of the thermal energy could be radiated before, and 20% during, the thermal quench. Halo currents could be reduced by 60% and, using argon/deuterium and neon/deuterium gas mixtures, runaway electron generation could be avoided. Most objectives of the ITER-like ICRH antenna have been demonstrated; matching with closely packed straps, ELM resilience, scattering matrix arc detection and operation at high power density (6.2 MW m-2) and antenna strap voltages (42 kV). Coupling measurements are in very good agreement with TOPICA modelling. © 2011 IAEA, Vienna.
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| 3. |
- Cea, B., et al.
(författare)
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Development and Evaluation of an Innovative Method Based on Dilution to Sample Solid and Condensable Fractions of Particles Emitted by Residential Wood Combustion
- 2021
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Ingår i: Energy & Fuels. - : American Chemical Society. - 0887-0624 .- 1520-5029. ; 35:23, s. 19705-
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Tidskriftsartikel (refereegranskat)abstract
- An innovative and simple method based on dilution, named as the dilution chamber (DC), allowing the measurement of solid and condensable fractions of particulate matter emitted by residential wood combustion appliances has been developed, and its performances have been evaluated. The DC method was then tested by five European institutes (Ineris, ISSI/ENEA, DTI, and RISE) on advanced residential wood log/pellet stoves, under nominal output and low output combustion conditions and using different fuel types. The aim of the study was to evaluate the capability of the DC method to collect the condensable fraction. The DC method was compared with another manual method used to collect the solid and condensable fractions at the same time, the dilution tunnel (DT), on four sampling platforms. A third method, a combining heated filter and impinger filled in with isopropanol collection (SPC-IPA), was also used by Ineris only for comparison with the DC method. PM measurements based on the DC method globally showed a linear correlation with PM measurements based on DT (R2 ranged between 0.81 and 0.99, p < 0.05) specifically for the residential wood stoves under low output conditions when the condensable fraction contributes the most. An analysis and quantification of PAHs related to the total mass of PM of samples taken by the DC method and performed by ENEA/ISSI showed that it produces a condensation effect of semivolatile species comparable or even greater than the DT method. PM emission factors calculated from PM measurements based on the DC method were (i) about 2- to 20-fold higher for the residential wood stoves (EF ranged between 201 to 2420 g GJ-1) compared to those obtained for the residential pellet stoves (EF ranged between 108 to 556 g GJ-1) and (ii) of the same magnitude of PM emission factors from the literature or the EMEP/EEA air pollutant emission inventory guidebook.
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| 4. |
- Fraboulet, I., et al.
(författare)
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European inter-comparison campaigns on pm and OGCS atmospheric emissions test methods from residential wood combustion using a stack simulator generating real biomass combustion gases
- 2020
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Ingår i: European Biomass Conference and Exhibition Proceedings. - : ETA-Florence Renewable Energies. ; , s. 812-816
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Konferensbidrag (refereegranskat)abstract
- The 20/20/20 target for Europe, will lead to an increased use of biomass combustion, e.g. using wood logs and wood pellets. On the other hand, the Air Quality Directive (2008/50/EC) lies down stringent requirements on maximum levels of particulate matter (PM) in the ambient air. Domestic wood combustion emits particulate matter (PM) which are of concern to authorities and the public. Several different methods of PM measurements have historically been used to perform type testing of solid fuelled residential appliances and boilers. This method shall give repeatable results that are of a guaranteed traceable accuracy, and by this means give the consumer reliable information on the suitability of a particular appliance or boiler. One of the main methods used in Europe consists of sampling the solid fraction of aerosols using a heated filter, this method does not include the collection of the condensable fraction, OGC measurements are performed using FID method.The aim of this work carried out within the EMPIR IMPRESS2 Project was to evaluate the performances of this method by performing intercomparisons using a stack simulator generating real biomass combustion gases.
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