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Publikācija: Radiolysis of Slightly Overstoichiometric Lithium Orthosilicate Pebbles

Publication Type Publications in RTU scientific journal
Funding for basic activity Unknown
Defending: ,
Publication language English (en)
Title in original language Radiolysis of Slightly Overstoichiometric Lithium Orthosilicate Pebbles
Field of research 2. Engineering and technology
Sub-field of research 2.4 Chemical engineering
Authors Arturs Zarins
Arnis Supe
Gunta Kizane
Regina Knitter
Ingars Reinholds
Aigars Vitins
Vija Tilika
Andris Actins
L. Baumane
Keywords lithium orthosilicate, radiolysis, ceramic pebbles
Abstract : One of the technological problems of a fusion reactor is the change in composition and structure of ceramic breeder (Li4SiO4 or Li2TiO3 pebbles) during long-term operation. Changes in the composition and structure of the Li4SiO4 ceramic pebbles at fast electron irradiation (E = 5 MeV, dose rate up to 88 MGy•h-1, absorbed dose up to 10.6 GGy) at 543-573 K were investigated in this study. Overstoichiometric (2.5 weight % of additional SiO2) lithium orthosilicate pebbles were fabricated by a melt-spraying process (Schott AG, Mainz, Germany). Three types of pebbles with different annealing time, diameter and grain size were investigated: pebbles annealed at 1073 K 1h (diameter <50 µm, grain size 1 µm), annealed at 1173 K 128 h (diameter <50 µm, grain size 8 µm) and pebbles annealed at 1243 K 168 h diameter 500 µm, grain size 10µm). Products of radiolysis were investigated by means of FTIR and XRD, TSL and ESR spectroscopy were used for detection of radiation defects. Additional phases were observed in the small pebbles after the irradiation up to 10.6 GGy by means of FTIR and XRD methods. The traces of LiOH, Li2CO3, Li2SiO3 and Li6Si2O7 were identified. The lines of SiO43- (HC2) and SiO33-(E’) ion radicals were observed in ESR spectra for all three samples, but F+ centres was observed only in ESR spectra of pebbles annealed at 1073 K 1h. For all three types of pebbles four maxima were observed in TSL glow curves, but in the optical spectra wide band at 3.5 eV. Comparison of obtained date for investigated pebbles allow to say that the sample #3 (pebbles annealed at 1243 K 168 h with diameters of 500 µm and a grain size of 10µm) have higher radiation stability as the other two
Reference Zarins, A., Supe, A., Kizane, G., Knitter, R., Reinholds, I., Vitins, A., Tilika, V., Actins, A., Baumane, L. Radiolysis of Slightly Overstoichiometric Lithium Orthosilicate Pebbles. Materials Sciences and Applied Chemistry. Vol.22, 2010, pp.100-104. ISSN 1407-7353.
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ID 8431