Search results for "Pebble"
showing 10 items of 42 documents
Tritium localisation and release from the ceramic pebbles of breeder
2004
Magnetic field (MF) effects on the radiolysis and tritium release from Li4SiO4 (FZK) and Li2TiO3 (CEA) ceramic pebbles were investigated. The tritium chemical forms in Li4SiO4 were estimated by means of lyomethods. In the case of the neutron fluence Fn 6 10 18 nm � 2 , the tritium is mostly in the T þ form, but in the case of Fn � 10 25 nm � 2 , the T þ form accounts for 86–95% of the tritium. A high subsurface concentration of tritium is characteristic of a separate pebble and correlates with the distribution of radiation-induced defects. The MF increases the radiolysis of Li4SiO4 by 20–25%. Irradiation with electrons to 1000 MGy at 1200 K increases the grain size by 5–10%, decreasing the …
TRITIUM RELEASE CHARACTERISTICS OF NEUTRON-IRRADIATED REFERENCE BERYLLIUM PEBBLES FOR THE HELIUM COOLED PEBBLE BED (HCPB) BLANKET
2011
In this paper, we present results on tritium release from the beryllium pebbles irradiated for 294 full power days from 17 April 2003 to November 2004 to the neutron fluence of 1.5-2 × 1025 m-2 (E>...
Thermo-mechanical testing of Li-ceramic for the helium cooled pebble bed (HCPB) breeding blanket
2004
The helium cooled pebble bed (HCPB) Test blanket module (TBM) for the DEMO Reactor foresees the utilization of lithiate ceramics as breeder in form of pebble beds. The pebbles are organized in several layers alternatively stacked among couples of cooling plates (CP). ENEA has launched an experimental programme for the out-of-pile thermo-mechanical testing of mock-ups simulating a portion of the HCPB-TBM. The programme foresees the fabrication and testing of different mock-ups, to be tested in the HE-FUS3 facility at ENEA Brasimone. The paper describes the HELICHETTA III campaign carried-out in 2003. In particular, the test section layout, the pebble filling procedure, the experimental set-u…
Formation and accumulation of radiation-induced defects and radiolysis products in modified lithium orthosilicate pebbles with additions of titanium …
2016
Abstract Lithium orthosilicate (Li4SiO4) pebbles with 2.5 wt.% excess of silicon dioxide (SiO2) are the European Union's designated reference tritium breeding ceramics for the Helium Cooled Pebble Bed (HCPB) Test Blanket Module (TBM). However, the latest irradiation experiments showed that the reference Li4SiO4 pebbles may crack and form fragments under operation conditions as expected in the HCPB TBM. Therefore, it has been suggested to change the chemical composition of the reference Li4SiO4 pebbles and to add titanium dioxide (TiO2), to obtain lithium metatitanate (Li2TiO3) as a second phase. The aim of this research was to investigate the formation and accumulation of radiation-induced …
Overview of the HCPB Research Activities in EUROfusion
2018
In the framework of the EUROfusion’s Power Plant Physics and Technology, the working package breeding blanket (BB) aims at investigating four different BB concepts for an EU demonstration fusion reactor (DEMO). One of these concepts is the helium-cooled pebble bed (HCPB) BB, which is based on the use of pebble beds of lithiated ternary compounds and Be or beryllides as tritium breeder and multiplier materials, respectively, EUROFER97 as structural steel and He as coolant. This paper aims at giving an overview of the EU HCPB BB Research and Development (R&D) being developed at KIT, in collaboration with Wigner-RCP, BUTE-INT, and CIEMAT. The paper gives an outline of the HCPB BB design evolut…
On the thermal conductivity of a single size beryllium pebble bed
2002
Experimental investigations on the thermal conductivity of packed pebble beds by the current pulse method
2003
New human remains of Archaic Homo sapiens and Lower Palaeolithic industries from Visogliano (Duino Aurisina, Trieste, Italy).
2000
New human remains have been found during recent excavations conducted in the lower section of Visogliano dolina (Trieste, Italy). They are represented by teeth and a fragment of particularly robust mandible that for their morphological and morphometrical characters can be generically attributed to archaic Homo sapiens. The lithic industry is formed by flakes, carinated points, scrapers, choppers and chopping tools and is characteristic of the Italian Pebble Culture. Sediments, pollen and faunal remains indicate that this part of the deposit was formed during interglacial climatic conditions in the early, but not initial phase of Middle Pleistocene (isotopic stadium 13 or 11).