Preliminary experimental evaluation of thermal conductivity of ceramic pebble beds

D Aquaro,R Lo Frano

doi:10.1088/1742-6596/501/1/012031

Abstract

This paper illustrates the preliminary experimental tests for determining the effective thermal conductivity of ceramic pebble beds versus temperature and compression strains.Ceramic pebble beds are promising candidates to be used in breeding blankets for nuclear fusion reactor as breeder and neutron multiplier.The tests were performed with an experimental rig, built at the DICI-University of Pisa, which permits to determine the thermal conductivity of pebble beds in steady state conditions, at several temperatures and compression forces. The values of thermal conductivity of pebble beds are obtained as function of a known conductivity of an alumina disc.The assessment of the method has been performed determining the effective thermal conductivity of alumina pebbles beds of different diameters. Void fraction and compression strains are the parameters that mainly influence the variability of the thermal conductivity of the beds.

Highlights

The breeding blanket of nuclear fusion reactor produces, by means of neutron capture, the tritium necessary for the fusion reaction, slows down the neutrons and permits to extract the thermal power
These breeders, packed in the form of pebble beds into a box-like structure, are characterized by strong mechanical loading arising from the differential thermal expansion between breeder pebbles and the containing structure
The knowledge of the effective thermal conductivity of pebble beds is important for a proper thermo-mechanical blanket design [1] and assessment of the heat transfer processes

Summary

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Preliminary experimental evaluation of thermal conductivity of ceramic pebble beds This content has been downloaded from IOPscience. Please scroll down to see the full text. Ser. 501 012031 (http://iopscience.iop.org/1742-6596/501/1/012031) View the table of contents for this issue, or go to the journal homepage for more. Download details: IP Address: 12.150.171.253 This content was downloaded on 16/04/2014 at 12:36 Please note that terms and conditions apply

Introduction

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Conclusion