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LNF:Technology: Difference between revisions
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[[File:Foto0005b.jpg|500px|thumb|right|SIMS sample-holder]] | [[File:Foto0005b.jpg|500px|thumb|right|SIMS sample-holder]] | ||
The main mission of the Fusion Technology Division of the Spanish National Fusion Laboratory is to undertake research on the properties as well as the radiation hardness and subsequent degradation of structural and functional materials for future fusion reactors. In particular, studies on reduced activity ferritic/martensitic steels and materials used for electrical isolation, diagnostic windows etc. are central to this work. In parallel, given that at present, there is no neutron source available that simulates the fluxes and energies required for material irradiation under predicted fusion reactor conditions, the division is involved in the development of suitable neutron sources for material irradiation (ENS, IFMIF, and DONES). These sources, when on-line, will facilitate accelerated irradiation damage studies in materials of interest. Finally, activities by the division in the area of lithium breeding blanket (LBB) development can be highlighted. This work is based on liquid metals (Li-Pb) or lithium based ceramics for LBB and on corrosion or permeation phenomena in blanket structural materials. | The main mission of the Fusion Technology Division of the Spanish [[Laboratorio Nacional de Fusión|National Fusion Laboratory]] is to undertake research on the properties as well as the radiation hardness and subsequent degradation of structural and functional materials for future fusion reactors. In particular, studies on reduced activity ferritic/martensitic steels and materials used for electrical isolation, diagnostic windows etc. are central to this work. In parallel, given that at present, there is no neutron source available that simulates the fluxes and energies required for material irradiation under predicted fusion reactor conditions, the division is involved in the development of suitable neutron sources for material irradiation (ENS, IFMIF, and DONES). These sources, when on-line, will facilitate accelerated irradiation damage studies in materials of interest. Finally, activities by the division in the area of lithium [[breeding blanket]] (LBB) development can be highlighted. This work is based on liquid metals (Li-Pb) or lithium based ceramics for LBB and on corrosion or permeation phenomena in blanket structural materials. | ||
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In-situ measurement capability and expertise. | In-situ measurement capability and expertise. | ||
To date a range of studies have been carried out on fusion candidate insulators. For instance, electrical, optical as well as hydrogen and helium diffusion properties are measured during irradiation. These studies are carried out at a controlled temperature, from liquid nitrogen up to 1000 C. For these studies special irradiation chambers and sample holders have been designed by the accelerator staff and have been fabricated at the | To date a range of studies have been carried out on fusion candidate insulators. For instance, electrical, optical as well as hydrogen and helium diffusion properties are measured during irradiation. These studies are carried out at a controlled temperature, from liquid nitrogen up to 1000 C. For these studies special irradiation chambers and sample holders have been designed by the accelerator staff and have been fabricated at the [[CIEMAT]] workshops. | ||
===60 keV DANFYSIK ION IMPLANTER=== | ===60 keV DANFYSIK ION IMPLANTER=== | ||
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The facility has been used regularly to implant H, He, D ions in metals and insulators in order to evaluate microstructural surface degradation, ionoluminescence, surface electrical degradation and to implant He and H isotopes to perform diffusion and desorption experiments. | The facility has been used regularly to implant H, He, D ions in metals and insulators in order to evaluate microstructural surface degradation, ionoluminescence, surface electrical degradation and to implant He and H isotopes to perform diffusion and desorption experiments. | ||
These studies can be carried out at controlled temperatures, from liquid nitrogen up to 1000 C. Available special irradiation chambers and sample holders have been designed by the implanter staff and fabricated at the | These studies can be carried out at controlled temperatures, from liquid nitrogen up to 1000 C. Available special irradiation chambers and sample holders have been designed by the implanter staff and fabricated at the [[CIEMAT]] workshops. | ||
===NAYADE Co-60 irradiation facility=== | ===NAYADE Co-60 irradiation facility=== | ||
[[File:Nayade3.png|200px|thumb|right|NAYADE]] | [[File:Nayade3.png|200px|thumb|right|NAYADE]] | ||
For gamma-ray irradiation studies CIEMAT possesses a Co-60 facility with unrestricted access. This permits extended temporal irradiation studies. The Nayade facility is a pool-type facility (1.2 m wide by 4.5 m deep) that uses water as the biological shield. This provides shielding for about 100,000 Ci of Co-60. Safety control is achieved through water level monitoring, radiation detectors, and water purity control by pH and conductivity measurements. The use of water as a biological shield also allows direct vision for positioning the sources and extracting of samples in different chambers. | For gamma-ray irradiation studies [[CIEMAT]] possesses a Co-60 facility with unrestricted access. This permits extended temporal irradiation studies. The Nayade facility is a pool-type facility (1.2 m wide by 4.5 m deep) that uses water as the biological shield. This provides shielding for about 100,000 Ci of Co-60. Safety control is achieved through water level monitoring, radiation detectors, and water purity control by pH and conductivity measurements. The use of water as a biological shield also allows direct vision for positioning the sources and extracting of samples in different chambers. | ||
[[File:Nayade6.png|200px|thumb|right|Irradiation rig]] | [[File:Nayade6.png|200px|thumb|right|Irradiation rig]] | ||
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*Irradiation at controlled temperatures and atmospheres, together with in-situ testing of electrical properties, is also possible. | *Irradiation at controlled temperatures and atmospheres, together with in-situ testing of electrical properties, is also possible. | ||
*Irradiation can be carried out at controlled temperature up to 300ºC. Gas flow (such as dry air or nitrogen) can be used during irradiation to minimize humidity. The uncertainty in the dose rate is better than 20% for a volume of about 283 cm<sup>3</sup>. | *Irradiation can be carried out at controlled temperature up to 300ºC. Gas flow (such as dry air or nitrogen) can be used during irradiation to minimize humidity. The uncertainty in the dose rate is better than 20% for a volume of about 283 cm<sup>3</sup>. | ||
Irradiation rigs to perform in-situ measurements at different dose rates and under different conditions are routinely fabricated at | Irradiation rigs to perform in-situ measurements at different dose rates and under different conditions are routinely fabricated at [[CIEMAT]] workshops. Sensors, cabling, laboratory equipment, feedthroughs, and environmental monitors (temperature, pressure, humidity, radiation) are available. | ||
*Dosimetry system | *Dosimetry system | ||
Routine gamma dosimetry is performed using commercially available Red Perspex™ 4034 Harwell dosimeters. These are widely used polymethylmethacrylate (PMMA) dosimeters. When exposed to ionising doses that exceed 1 kGy, the Red 4034 polymer starts to darken due to the formation of a new absorption band extending from 600 nm to beyond 700 nm (it peaks at 615 nm). The absorbed dose is therefore determined by measuring radiation-induced absorbance in the 630nm-650 nm range where post-irradiation fading is minimal. For this the 640 nm wavelength is used as measurement wavelength. The absorbance per unit thickness, expressed in cm<sup>-1</sup>, is the dose-dependent quantity measured against air as reference. These dosimeters has been shown to be valid in the range of 5 to 50 kGy and their accuracy is better than 10 per cent. The Red 4034 dosimeters are pre-conditioned in a fixed humidity environment and hermetically sealed in polyester/aluminium foil/polyethylene laminate pouches, as absorbed water concentration was identified as a parameter which could influence the spectrophotometric response and hence the dose readout. Keeping the dosimeter in its packaging is mandatory to use the calibration curves (absorbance at 640nm (cm-1) related to dose) supplied by the manufacturer. The temperature sensitivity of the dosimeter is the most important environmental dependence. From a practical point of view, the Red 4034 dosimeters are temperature-independent up to 40ºC, provided that measurements are made as soon as possible after ending an irradiation | Routine gamma dosimetry is performed using commercially available Red Perspex™ 4034 Harwell dosimeters. These are widely used polymethylmethacrylate (PMMA) dosimeters. When exposed to ionising doses that exceed 1 kGy, the Red 4034 polymer starts to darken due to the formation of a new absorption band extending from 600 nm to beyond 700 nm (it peaks at 615 nm). The absorbed dose is therefore determined by measuring radiation-induced absorbance in the 630nm-650 nm range where post-irradiation fading is minimal. For this the 640 nm wavelength is used as measurement wavelength. The absorbance per unit thickness, expressed in cm<sup>-1</sup>, is the dose-dependent quantity measured against air as reference. These dosimeters has been shown to be valid in the range of 5 to 50 kGy and their accuracy is better than 10 per cent. The Red 4034 dosimeters are pre-conditioned in a fixed humidity environment and hermetically sealed in polyester/aluminium foil/polyethylene laminate pouches, as absorbed water concentration was identified as a parameter which could influence the spectrophotometric response and hence the dose readout. Keeping the dosimeter in its packaging is mandatory to use the calibration curves (absorbance at 640nm (cm-1) related to dose) supplied by the manufacturer. The temperature sensitivity of the dosimeter is the most important environmental dependence. From a practical point of view, the Red 4034 dosimeters are temperature-independent up to 40ºC, provided that measurements are made as soon as possible after ending an irradiation | ||