In support of the breeder blanket development program, the EU is conducting a dedicated neutronic... more In support of the breeder blanket development program, the EU is conducting a dedicated neutronics R&D effort to provide the basis for the design of nuclear tests to be performed in ITER on the Test Blanket Modules (TBMs). It includes the development of computational tools comprising both Monte-Carlo and deterministic transport, sensitivity and uncertainty codes, the generation of high quality neutron crosssection and covariance data libraries. These are validated experimentally in view of their application in the ITER TBM and the DEMO design. To this purpose, two neutronics experiments have been carried out on mock-ups of both the Helium Cooled Pebble Bed (HCPB) and the Helium Cooled Lithium Lead (HCLL) variants of ITER TBMs, at 14-MeV neutron sources. Redundant experimental techniques have been used to measure the resulting tritium production rate and the neutron and gamma ray spectra which are needed to predict the blanket shielding performance, nuclear power production and all nuclear loads. The comparison of experiment and corresponding calculation is obtained with the associated uncertainty margin based on experimental as well as calculational uncertainties. At the same time, suitable nuclear measuring techniques for TBMs in ITER, in particular for the tritium production, are being developed, optimised, and tested in the mock-up experiments.
The GERDA experiment at the Laboratori Nazionali del Gran Sasso (LNGS) searches for the neutrinol... more The GERDA experiment at the Laboratori Nazionali del Gran Sasso (LNGS) searches for the neutrinoless double beta decay of 76 Ge. In view of the GERDA Phase II data collection, four new 228 Th radioactive sources for the calibration of the germanium detectors enriched in 76 Ge have been produced with a new technique, leading to a reduced neutron flux from (α, n) reactions. The gamma activities of the sources were determined with a total uncertainty of ∼ 4% using an ultra-low background HPGe detector operated underground at LNGS. The emitted neutron flux was determined using a low background LiI(Eu) detector and a 3 He counter at LNGS. In both cases, the measured neutron activity is ∼ 10 −6 n/(s·Bq), with a reduction of about one order of magnitude with respect to commercially available 228 Th sources. Additionally, a specific leak test with a sensitivity to leaks down to ∼ 10 mBq was developed to investigate the tightness of the stainless steel capsules housing the sources after their use in cryogenic environment.
In 2014, the first three comparisons of activity measurements of (18)F were carried out at the VN... more In 2014, the first three comparisons of activity measurements of (18)F were carried out at the VNIIM, NPL and the ENEA-INMRI using the BIPM's Transfer Instrument of the International Reference System. The transfer instrument and the NMIs primary measurement methods are briefly described. The degrees of equivalence with the key comparison reference value defined in the frame of the corresponding SIR comparison have been evaluated. World-wide consistency of activity measurements of (18)F is demonstrated.
The effect of radon diffusion and distribution between a (226)Ra matrix and the top air gap insid... more The effect of radon diffusion and distribution between a (226)Ra matrix and the top air gap inside sample containers for gamma-ray spectrometry was studied. Containers filled at almost 100% or just 70% of total capacity yielded correction factors of about 7% and 20% respectively. Applying these correction factors allowed activity values calculated from (226)Ra or radon decay products to agree within 2%.
Medium sized spherical particles of Li2TiO3 (with diameters below 100 µm) can be fabricated by a ... more Medium sized spherical particles of Li2TiO3 (with diameters below 100 µm) can be fabricated by a classical, inorganic sol-gel process, from commercially available TiCl4. Elaborated process consists of the following main steps: (1) dissolving of TiCl4 in concentrated aqueous HCl; (2) formation of sol emulsion in 2-ethylhexanol-1 containing the surfactant SPAN-80 (EH); (3) gelation of emulsion drops by extraction of
Microspheres of Li2TiO3 were fabricated by a classical, inorganic sol-gel process from commercial... more Microspheres of Li2TiO3 were fabricated by a classical, inorganic sol-gel process from commercially available TiCl4. Elaborated process consists of the following main steps: (1) dissolving of TiCl4 in concentrated aqueous HCl and addition of LiOH; (2) formation of sol emulsion in 2-ethylhexanol-1 containing the surfactant SPAN-80 (EH); (3) gelation of emulsion drops by extraction of water with partially dehydrated EH;
ABSTRACT Industrial solid state oxygen sensors, using fully stabilized zirconia as electrolyte, w... more ABSTRACT Industrial solid state oxygen sensors, using fully stabilized zirconia as electrolyte, were modified and used to split water vapor, mixed with inert gas. Such conditions were chosen for simulating the tritium removal from the ceramic breeder materials in solid blanket fusion reactors. The single cell performances were investigated at 973 K and 200 cm³/min flow rate using argon/water vapor mixtures ranging from 100 to 700 vpm. The splitting efficiency was evaluated at 80%; steady state conditions were reached in a few minutes. 14 refs., 4 figs., 1 tab.
Journal of Radioanalytical and Nuclear Chemistry Articles, 1991
In the context of the European programs for the future fusion reactors, the Process Chemistry Dep... more In the context of the European programs for the future fusion reactors, the Process Chemistry Department of ENEA, Casaccia Center (Rome), has been involved in preparing ceramic blanket materials as tritium breeders; a special consideration has been addressed to the nuclear characterization of LiAlO2 and Li2ZrO3. In this paper are reported: (a) neutron irradiation of ceramic specimens in TRIGA reactor
Journal of Radioanalytical and Nuclear Chemistry, 1997
Neutron Activation Analysis (NAA) was applied to the characterization of lithious ceramic materia... more Neutron Activation Analysis (NAA) was applied to the characterization of lithious ceramic materials to be used as tritiogenic breeders in future fusion reactors. After neutron irradiation, measurements by T-spectrometry were performed on the activated impurities, particularly on the ones with large neutron cross section. Irradiated samples were then annealed at rising temperatures, to obtain a fractional release of the tritium [formed by (n,~t) reaction on lithium] as element (HT/'I'2) or tritiated water (HTO/T20). Barium and antimony were determined by NAA, on request of Italian Courts, as evidence of gunshot residues (GSR), on hands and clothes of suspected people. The sample is left unchanged, even if slightly radioactive, allowing further examinations, in case of controversial results. In some actual Cases, NAA was performed on samples already examined by sCanning electron microscopy (SEM/EDX), allowing the determination of several more elements and a more definite identification of the ammunitions involved in the crime.
Journal of Radioanalytical and Nuclear Chemistry Articles, 1989
Instrumental neutron activation analysis (INAA) has been applied to the determination of 21 eleme... more Instrumental neutron activation analysis (INAA) has been applied to the determination of 21 elements in 8 different vegetal samples, to be used as ref~ence materials in 35 European laboratories (CII). Many o,f these elements hitherto have not been evaluated; they can be useful markers in many environmental problems. The INAA values are compared with CII non-nuclear analytical techniques results. Some rare earths elements (REE) have been also determined and their ehondritie ratio versus atomic radius is reported.
An original dissolution method for irradiated Li2TiO3 in aqueous H2O2 was developed. One could ea... more An original dissolution method for irradiated Li2TiO3 in aqueous H2O2 was developed. One could easily obtain fine Li2TiO3 powders from the solution through drying and calcination. Li2TiO3 pebbles (size ∼0.6 mm, above 90% TD) were obtained from the `reprocessed' powders. These solutions were also suitable for the formation of a sol emulsion in 2-ethyl-hexanol-1, from which gelled microspheres of lithium
Within the frame of the COMPLIMENT experiment, y-LiAlO, specimens with different microstructures ... more Within the frame of the COMPLIMENT experiment, y-LiAlO, specimens with different microstructures (grain size distributions) were tested in the same environmental conditions to compare the effects caused by 6Li(n, cu)T reaction and by fast neutron scattering, the damaging dose being held at about the same level (1.6-1.8 dpa). The tritium retention times were obtained by the tritium removal of isothermal annealing under He+O.l% H, sweeping gas. In spite of the different Li burnups (2.5% and 0.25%) and the residual tritium concentrations which were found in the irradiated specimens (4.3 Ci/g and 0.09 Ci/g, respectively, for specimens held at 450°C during the irradiations), the kinetics of tritium removal was not found to be discriminated by the two different irradiations. Moreover, the results were found to agree with those previously obtained by the "in-situ" TEQUILA experiment, performed on the same type of Li ceramics. Hence, the apparent first order desorption mechanism has been confirmed to control the kinetics of tritium removal from the porous fine grain y-LiAlO, ceramics.
This paper discusses measurements of impurities and tritium releasing characteristics of Lithium ... more This paper discusses measurements of impurities and tritium releasing characteristics of Lithium Aluminate and zirconate, prepared by ENEA in the frame of the European Program on Fusion Technology, performed, respectively, by neutron activation analysis (NAA) and out of pile annealing. The resulting tritium removing rate from the ceramics was interpreted in terms of surface desorption kinetics. With reference purge gas (He + 0.1% Hâ), the predominant form of tritium, released by lithium aluminate is HT/Tâ, HTO/TâO by lithium zirconate. The latter was found to have a better performance in tritium release than aluminate. The presence of moisture was found to catalyze the tritium release at lower temperatures.
A neutronics experiment has been performed in the frame of European Fusion Technology Program on ... more A neutronics experiment has been performed in the frame of European Fusion Technology Program on a mock-up of the EU Test Blanket Module (TBM), HCPB concept, with the objective to validate the capability of nuclear data to predict nuclear responses, such as the tritium production rate (TPR), with qualified uncertainties. In the experiment, the TPR has been measured using Li 2 CO 3 pellets located at various depths at two symmetrical positions at each depth, one in the upper and one in the lower breeder cassette. Three independent measurements were performed by ENEA, TUD/VKTA and JAEA. The neutron flux in the beryllium layer was measured as well using activation foils.
In support of the breeder blanket development program, the EU is conducting a dedicated neutronic... more In support of the breeder blanket development program, the EU is conducting a dedicated neutronics R&D effort to provide the basis for the design of nuclear tests to be performed in ITER on the Test Blanket Modules (TBMs). It includes the development of computational tools comprising both Monte-Carlo and deterministic transport, sensitivity and uncertainty codes, the generation of high quality neutron crosssection and covariance data libraries. These are validated experimentally in view of their application in the ITER TBM and the DEMO design. To this purpose, two neutronics experiments have been carried out on mock-ups of both the Helium Cooled Pebble Bed (HCPB) and the Helium Cooled Lithium Lead (HCLL) variants of ITER TBMs, at 14-MeV neutron sources. Redundant experimental techniques have been used to measure the resulting tritium production rate and the neutron and gamma ray spectra which are needed to predict the blanket shielding performance, nuclear power production and all nuclear loads. The comparison of experiment and corresponding calculation is obtained with the associated uncertainty margin based on experimental as well as calculational uncertainties. At the same time, suitable nuclear measuring techniques for TBMs in ITER, in particular for the tritium production, are being developed, optimised, and tested in the mock-up experiments.
The GERDA experiment at the Laboratori Nazionali del Gran Sasso (LNGS) searches for the neutrinol... more The GERDA experiment at the Laboratori Nazionali del Gran Sasso (LNGS) searches for the neutrinoless double beta decay of 76 Ge. In view of the GERDA Phase II data collection, four new 228 Th radioactive sources for the calibration of the germanium detectors enriched in 76 Ge have been produced with a new technique, leading to a reduced neutron flux from (α, n) reactions. The gamma activities of the sources were determined with a total uncertainty of ∼ 4% using an ultra-low background HPGe detector operated underground at LNGS. The emitted neutron flux was determined using a low background LiI(Eu) detector and a 3 He counter at LNGS. In both cases, the measured neutron activity is ∼ 10 −6 n/(s·Bq), with a reduction of about one order of magnitude with respect to commercially available 228 Th sources. Additionally, a specific leak test with a sensitivity to leaks down to ∼ 10 mBq was developed to investigate the tightness of the stainless steel capsules housing the sources after their use in cryogenic environment.
In 2014, the first three comparisons of activity measurements of (18)F were carried out at the VN... more In 2014, the first three comparisons of activity measurements of (18)F were carried out at the VNIIM, NPL and the ENEA-INMRI using the BIPM's Transfer Instrument of the International Reference System. The transfer instrument and the NMIs primary measurement methods are briefly described. The degrees of equivalence with the key comparison reference value defined in the frame of the corresponding SIR comparison have been evaluated. World-wide consistency of activity measurements of (18)F is demonstrated.
The effect of radon diffusion and distribution between a (226)Ra matrix and the top air gap insid... more The effect of radon diffusion and distribution between a (226)Ra matrix and the top air gap inside sample containers for gamma-ray spectrometry was studied. Containers filled at almost 100% or just 70% of total capacity yielded correction factors of about 7% and 20% respectively. Applying these correction factors allowed activity values calculated from (226)Ra or radon decay products to agree within 2%.
Medium sized spherical particles of Li2TiO3 (with diameters below 100 µm) can be fabricated by a ... more Medium sized spherical particles of Li2TiO3 (with diameters below 100 µm) can be fabricated by a classical, inorganic sol-gel process, from commercially available TiCl4. Elaborated process consists of the following main steps: (1) dissolving of TiCl4 in concentrated aqueous HCl; (2) formation of sol emulsion in 2-ethylhexanol-1 containing the surfactant SPAN-80 (EH); (3) gelation of emulsion drops by extraction of
Microspheres of Li2TiO3 were fabricated by a classical, inorganic sol-gel process from commercial... more Microspheres of Li2TiO3 were fabricated by a classical, inorganic sol-gel process from commercially available TiCl4. Elaborated process consists of the following main steps: (1) dissolving of TiCl4 in concentrated aqueous HCl and addition of LiOH; (2) formation of sol emulsion in 2-ethylhexanol-1 containing the surfactant SPAN-80 (EH); (3) gelation of emulsion drops by extraction of water with partially dehydrated EH;
ABSTRACT Industrial solid state oxygen sensors, using fully stabilized zirconia as electrolyte, w... more ABSTRACT Industrial solid state oxygen sensors, using fully stabilized zirconia as electrolyte, were modified and used to split water vapor, mixed with inert gas. Such conditions were chosen for simulating the tritium removal from the ceramic breeder materials in solid blanket fusion reactors. The single cell performances were investigated at 973 K and 200 cm³/min flow rate using argon/water vapor mixtures ranging from 100 to 700 vpm. The splitting efficiency was evaluated at 80%; steady state conditions were reached in a few minutes. 14 refs., 4 figs., 1 tab.
Journal of Radioanalytical and Nuclear Chemistry Articles, 1991
In the context of the European programs for the future fusion reactors, the Process Chemistry Dep... more In the context of the European programs for the future fusion reactors, the Process Chemistry Department of ENEA, Casaccia Center (Rome), has been involved in preparing ceramic blanket materials as tritium breeders; a special consideration has been addressed to the nuclear characterization of LiAlO2 and Li2ZrO3. In this paper are reported: (a) neutron irradiation of ceramic specimens in TRIGA reactor
Journal of Radioanalytical and Nuclear Chemistry, 1997
Neutron Activation Analysis (NAA) was applied to the characterization of lithious ceramic materia... more Neutron Activation Analysis (NAA) was applied to the characterization of lithious ceramic materials to be used as tritiogenic breeders in future fusion reactors. After neutron irradiation, measurements by T-spectrometry were performed on the activated impurities, particularly on the ones with large neutron cross section. Irradiated samples were then annealed at rising temperatures, to obtain a fractional release of the tritium [formed by (n,~t) reaction on lithium] as element (HT/'I'2) or tritiated water (HTO/T20). Barium and antimony were determined by NAA, on request of Italian Courts, as evidence of gunshot residues (GSR), on hands and clothes of suspected people. The sample is left unchanged, even if slightly radioactive, allowing further examinations, in case of controversial results. In some actual Cases, NAA was performed on samples already examined by sCanning electron microscopy (SEM/EDX), allowing the determination of several more elements and a more definite identification of the ammunitions involved in the crime.
Journal of Radioanalytical and Nuclear Chemistry Articles, 1989
Instrumental neutron activation analysis (INAA) has been applied to the determination of 21 eleme... more Instrumental neutron activation analysis (INAA) has been applied to the determination of 21 elements in 8 different vegetal samples, to be used as ref~ence materials in 35 European laboratories (CII). Many o,f these elements hitherto have not been evaluated; they can be useful markers in many environmental problems. The INAA values are compared with CII non-nuclear analytical techniques results. Some rare earths elements (REE) have been also determined and their ehondritie ratio versus atomic radius is reported.
An original dissolution method for irradiated Li2TiO3 in aqueous H2O2 was developed. One could ea... more An original dissolution method for irradiated Li2TiO3 in aqueous H2O2 was developed. One could easily obtain fine Li2TiO3 powders from the solution through drying and calcination. Li2TiO3 pebbles (size ∼0.6 mm, above 90% TD) were obtained from the `reprocessed' powders. These solutions were also suitable for the formation of a sol emulsion in 2-ethyl-hexanol-1, from which gelled microspheres of lithium
Within the frame of the COMPLIMENT experiment, y-LiAlO, specimens with different microstructures ... more Within the frame of the COMPLIMENT experiment, y-LiAlO, specimens with different microstructures (grain size distributions) were tested in the same environmental conditions to compare the effects caused by 6Li(n, cu)T reaction and by fast neutron scattering, the damaging dose being held at about the same level (1.6-1.8 dpa). The tritium retention times were obtained by the tritium removal of isothermal annealing under He+O.l% H, sweeping gas. In spite of the different Li burnups (2.5% and 0.25%) and the residual tritium concentrations which were found in the irradiated specimens (4.3 Ci/g and 0.09 Ci/g, respectively, for specimens held at 450°C during the irradiations), the kinetics of tritium removal was not found to be discriminated by the two different irradiations. Moreover, the results were found to agree with those previously obtained by the "in-situ" TEQUILA experiment, performed on the same type of Li ceramics. Hence, the apparent first order desorption mechanism has been confirmed to control the kinetics of tritium removal from the porous fine grain y-LiAlO, ceramics.
This paper discusses measurements of impurities and tritium releasing characteristics of Lithium ... more This paper discusses measurements of impurities and tritium releasing characteristics of Lithium Aluminate and zirconate, prepared by ENEA in the frame of the European Program on Fusion Technology, performed, respectively, by neutron activation analysis (NAA) and out of pile annealing. The resulting tritium removing rate from the ceramics was interpreted in terms of surface desorption kinetics. With reference purge gas (He + 0.1% Hâ), the predominant form of tritium, released by lithium aluminate is HT/Tâ, HTO/TâO by lithium zirconate. The latter was found to have a better performance in tritium release than aluminate. The presence of moisture was found to catalyze the tritium release at lower temperatures.
A neutronics experiment has been performed in the frame of European Fusion Technology Program on ... more A neutronics experiment has been performed in the frame of European Fusion Technology Program on a mock-up of the EU Test Blanket Module (TBM), HCPB concept, with the objective to validate the capability of nuclear data to predict nuclear responses, such as the tritium production rate (TPR), with qualified uncertainties. In the experiment, the TPR has been measured using Li 2 CO 3 pellets located at various depths at two symmetrical positions at each depth, one in the upper and one in the lower breeder cassette. Three independent measurements were performed by ENEA, TUD/VKTA and JAEA. The neutron flux in the beryllium layer was measured as well using activation foils.
Uploads
Papers by P. Carconi