Characterizing the effects of elevated temperature on the air void pore structure of advanced gas-cooled reactor pressure vessel concrete using x-ray computed tomography
1 Nuclear FiRST Doctoral Training Centre, Universities of Sheffield & Manchester, UK
2 Department of Civil and Structural Engineering, University of Sheffield, UK
3 Research Centre for Radwaste and Decommissioning, University of Manchester, UK
4 Manchester X-ray Imaging Facility, University of Manchester, UK
a e-mail: RCStein1@sheffield.ac.uk
X-ray computed tomography (X-ray CT) has been applied to nondestructively characterise changes in the microstructure of a concrete used in the pressure vessel structure of Advanced Gas-cooled Reactors (AGR) in the UK. Concrete specimens were conditioned at temperatures of 105 °C and 250 °C, to simulate the maximum thermal load expected to occur during a loss of coolant accident (LOCA). Following thermal treatment, these specimens along with an unconditioned control sample were characterised using micro-focus X-ray CT with a spatial resolution of 14.6 microns. The results indicate that the air void pore structure of the specimens experienced significant volume changes as a result of the increasing temperature. The increase in the porous volume was more prevalent at 250 °C. Alterations in air void size distributions were characterized with respect to the unconditioned control specimen. These findings appear to correlate with changes in the uni-axial compressive strength of the conditioned concrete.
© Owned by the authors, published by EDP Sciences, 2013
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