The Helium-Cooled Pebble Bed breeding blanket foresees the use of the lithium orthosilicate (Li4SiO4) pebble beds as promising tritium-breeding materials for fusion reactor, because of the advantages in terms of tritium production and release, low activation characteristics, cooling capability, low thermal expansion coefficient and, high thermal conductivity. Ceramic breeder pebbles have been long investigated in the recent years and are currently a focus for several research groups, particularly for what concerns the physical-chemical and the thermo-mechanical properties under irradiation conditions, and the overall behaviour in blanket modules. A variety of industrial processes, even if far from industrial standard, has been proposed for making 0.1-1 mm orthosilicate pebbles diameter; nevertheless some manufacturing problems have been observed like e.g. the chemical stability (agglomeration phenomena). The aim of this study is to provide a new methodology for pebble bed production (according to the diagram below), based on the drip casting method, jointly developed by the Department of Civil and Industrial Engineering (DICI) of the University of Pisa and Industrie Bitossi. This new (and alternative) manufacturing technology allows to produce stable and well-sized Li4SiO4 pebbles, so to prevent hydration/carbonation phenomena and in turn avoid degradation of thermo-mechanical properties during the storage. A description of the new adopted methodology and results are presented and discussed. In addition, the chemical and physical properties of the material so obtained are compared to those of pebbles studied in other research centers. Indeed, the results may contribute also to optimize the design of the envisaged fusion breeding blankets.
Manufacturing Technology And Properties Of Ceramic Pebbles For Breeding Blanket
LO FRANO, ROSA;PUCCINI, MONICA;AQUARO, DONATO;VITOLO, SANDRA;FORGIONE, NICOLA;
2016-01-01
Abstract
The Helium-Cooled Pebble Bed breeding blanket foresees the use of the lithium orthosilicate (Li4SiO4) pebble beds as promising tritium-breeding materials for fusion reactor, because of the advantages in terms of tritium production and release, low activation characteristics, cooling capability, low thermal expansion coefficient and, high thermal conductivity. Ceramic breeder pebbles have been long investigated in the recent years and are currently a focus for several research groups, particularly for what concerns the physical-chemical and the thermo-mechanical properties under irradiation conditions, and the overall behaviour in blanket modules. A variety of industrial processes, even if far from industrial standard, has been proposed for making 0.1-1 mm orthosilicate pebbles diameter; nevertheless some manufacturing problems have been observed like e.g. the chemical stability (agglomeration phenomena). The aim of this study is to provide a new methodology for pebble bed production (according to the diagram below), based on the drip casting method, jointly developed by the Department of Civil and Industrial Engineering (DICI) of the University of Pisa and Industrie Bitossi. This new (and alternative) manufacturing technology allows to produce stable and well-sized Li4SiO4 pebbles, so to prevent hydration/carbonation phenomena and in turn avoid degradation of thermo-mechanical properties during the storage. A description of the new adopted methodology and results are presented and discussed. In addition, the chemical and physical properties of the material so obtained are compared to those of pebbles studied in other research centers. Indeed, the results may contribute also to optimize the design of the envisaged fusion breeding blankets.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
