1,720,972 research outputs found
Application of Eurofer97 steels for demo divertor cassette irradiated at temperature below 350 °C
Full text linkL'acciaio inossidabile austenitico AISI 316 L(N) IG è utilizzato come materiale strutturale per i principali componenti in-vessel di ITER. Quando le fluenze neutroniche aumentano come nei componenti in-vessel di DEMO, non è possibile utilizzare l’AISI 316 in quanto è soggetto a forte attivazione a causa dell'elevata presenza di Nichel. Devono essere previsti acciai ferritici/martensitici ad attivazione ridotta come l’Eurofer97 che mantengono buone proprietà thermo-meccaniche e stabilità dimensionale sotto irraggiamento (i.e. resitenza al rigonfiamento). L'obiettivo principale del presente lavoro è quello di evidenziare lo stato dell’arte circa le proprietà meccaniche dell’Eurofer97 irraggiato a temperature al di sotto di 350 °C. In base ai dati raccolti, è discussa la fattibilità per applicazioni strutturali dell’Eurofer97 e degli acciai ferritici/martensitici nel caso di impiego dell’acqua come fluido refrigerante per la cassetta del divertore. Questo rapporto a questo stadio non tiene conto degli impatti della corrosione sugli acciai RAFMs che sono probabilmente meno critici degli effetti dell’infragilimento da irraggiamento.The austenitic stainless steel AISI 316 L(N) IG is used as structural material for the main ITER in-vessel components. When neutron fluences increase, as in DEMO in-vessel components, it is not possible to use AISI 316, which is subject to strong activation due to its high nickel content. Ferritic/martensitic steels with reduced activation properties as Eurofer97 which keep good thermo-mechanical properties and good dimensional stability under irradiation (i.e. resistance to swelling), must be envisaged. The principal objective of the present paper is to address the current status about the mechanical properties of Eurofer97 irradiated at temperature below 350 °C. Based on the collected data, the feasibility of Eurofer97 and Reduced Activation Ferritic/Martensitic (RAFM) steels for structural applications is discussed in case of using water as coolant for divertor cassette. This report at this stage does not account for corrosion-related impacts on RAFMs behavior, which are likely less critical than irradiation embrittlement effects
Microporous inorganic membranes for gas separation and purification
No full textThe importance of inorganic membranes for gas separation and purification is analyzed. Although the cost of inorganic membranes is higher than that for polymeric membranes, they have higher permeance, selectivity and better resistance to higher pressure and temperature. The main materials used for porous inorganic membranes are alumina (Al2O3), silica (SiO2), zirconia (ZrO2), zeolite and carbon. Ceramics are compounds of metallic and non-metallic elements. They generally have a macroporous support, an intermediate layer and a small porous top layer. Because the Knudsen gas separation regime has a very low selectivity, various membrane surface modification techniques have started to be experimented with at a number of laboratories. The research focuses on materials that exhibit molecular sieving properties, such as silica, zeolites, MOFs (metal-organic frameworks), graphene and carbon. Finally, gas transport mechanisms through porous membranes are summarized
Low pressure fusion exhaust gases separation
No full textPlasma enhancement gases (PEGs) (such as: nitrogen, neon, argon and other inert gases) are injected into the plasma of several tokamaks in order to reduce the power load over the plasma facing components. The exhaust gas in the tokamak demonstration reactor (DEMO) consists of more than 90% of unburned fuel gas (D and T) and the remaining part will be He, PEGs and impurities. In DEMO reactor it is foreseen to recover the fuel gas and PEGs. The research focuses to remove the He from fuel gas and PEGs from fusion reactor. For this purpose, six commercial ceramic membranes have been tested at a permeation apparatus built at ENEA Casaccia laboratories. Single gas permeances for H2, He, Ar and air were measured with a pressure drop across the membranes between 10 Pa up to 100 kPa at room temperature. The selectivities found are low except for the 0.5 nm pore size membranes. The membranes have been supplied by Ceramiques Tecniques et Industrielles (CTI SA, France)
Plasma enhancement gases (PEGs) separation using a carbon molecular sieve (CMS) membrane
No full textPlasma enhancement gases (PEGs) (such as: N-2, Ne, Ar and other inert gases) are injected into the plasma of several tokamaks in order to reduce the power load over the plasma facing components. The exhaust gas in the tokamak demonstration reactor (DEMO) consists of more than 90% of unburned fuel gas (D and T) and the remaining part will be He, PEGs and impurities. In DEMO reactor it is foreseen to recover the fuel gas and PEGs. For this purpose in this study a carbon molecular sieve (CMS) membrane and its precursor substrate have been tested at a permeation apparatus built at ENEA Casaccia laboratories. Single gas permeances for H-2, He, N-2 and Ar were measured with a pressure drop across the membranes between 10 Pa up to 140 kPa at room temperature, 144 degrees C and 250 degrees C. We found that H-2 to N-2 selectivity at 250 degrees C is equal to 47.68 while for H-2 to Ar is equal to 35.05
Plasma enhancement gases (PEGs) separation using a carbon molecular sieve (CMS) membrane
No full textPlasma enhancement gases (PEGs) (such as: N2, Ne, Ar and other inert gases) are injected into the plasma of several tokamaks in order to reduce the power load over the plasma facing components. The exhaust gas in the tokamak demonstration reactor (DEMO) consists of more than 90% of unburned fuel gas (D and T) and the remaining part will be He, PEGs and impurities. In DEMO reactor it is foreseen to recover the fuel gas and PEGs. For this purpose in this study a carbon molecular sieve (CMS) membrane and its precursor substrate have been tested at a permeation apparatus built at ENEA Casaccia laboratories. Single gas permeances for H2, He, N2 and Ar were measured with a pressure drop across the membranes between 10 Pa up to 140 kPa at room temperature, 144 °C and 250 °C. We found that H2 to N2 selectivity at 250°C is equal to 47.68 while for H2 to Ar is equal to 35.05
OECD-CSNI Benchmark problem 2 on combustible gas distribution in a large dry containment case DA: calculation results using FUMO and MARCH 2 computer codes
No full textPresentation of the UNIPI calculation results, obatined using FUMO and MARCH 2 computer codes, for the OECD-CSNI Benchmark problem 2 on combustible gas distribution in a large dry containment of a reference nuclear power plant
Ceramic Membranes for the Separation of Plasma Enhancement Gases
No full textLow and medium Z impurity seeding gases, or plasma enhancement gases (PEGs) will be injected into the plasma of a Tokamak to convert the plasma thermal energy to ultraviolet and soft X-ray radiation. Possible PEGs are nitrogen, neon, argon, xenon and other inert gases. for the exhaust processing system of the demonstration fusion reactor (DEMO), the use of inorganic membranes was recently taken into consideration. Two commercial ceramic membranes (produced by Atech Innovations GmbH, Germany) were tested at a permeation apparatus built at ENEA Casaccia laboratories. Single gas permeances for H2, He, Ar and N2 were measured with a pressure drop across the membranes between 10 Pa up to 130 kPa at room temperature. For both membranes the permeance order follows the Knudsen regime. The Knudsen permeance measured for the two membranes are on the order of 10−7–10−8. The selectivities found are low (similar to ideal Knudsen). © 2018, Springer Fachmedien Wiesbaden GmbH, part of Springer Nature
Fusion Exhaust Gas Separation with a Carbon Molecular Sieve (CMS) Membrane
No full textThe exhaust gas in the future Tokamak demonstration reactor (DEMO) consists of more than 80 % of unburned fuel gas (D and T) with the balance being He, plasma enhancement gases (PEGs), and impurities. In DEMO we plan to recover the fuel gas (D and T) and PEGs. The paper focuses on the removal of He from the fuel gas and PEGs from the fusion reactors. Hence, the aim of the research is to test potential technologies to achieve this goal. In this paper, a carbon molecular sieve (CMS) membrane supplied by Tecnalia (Spain) is tested to remove the He along with D and T whilst retaining the PEGs
Ceramic Membranes for the Separation of Plasma Enhancement Gases
No full textLow and medium Z impurity seeding gases, or plasma enhancement gases (PEGs) will be injected into the plasma of a Tokamak to convert the plasma thermal energy to ultraviolet and soft X-ray radiation. Possible PEGs are nitrogen, neon, argon, xenon and other inert gases. for the exhaust processing system of the demonstration fusion reactor (DEMO), the use of inorganic membranes was recently taken into consideration. Two commercial ceramic membranes (produced by Atech Innovations GmbH, Germany) were tested at a permeation apparatus built at ENEA Casaccia laboratories. Single gas permeances for H2, He, Ar and N2 were measured with a pressure drop across the membranes between 10 Pa up to 130 kPa at room temperature. For both membranes the permeance order follows the Knudsen regime. The Knudsen permeance measured for the two membranes are on the order of 10−7–10−8. The selectivities found are low (similar to ideal Knudsen)
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