Abstract
This study investigates the alteration of felsic sandstone-type rock, which is used as a coarse aggregate in concrete, subject to the effects of gamma-ray and neutron irradiation. The effects of three gamma-ray doses (27, 55, and 108 MGy) and four neutron fluence levels (1.22, 2.19, 6.99, and 14.30 × 1019 n/cm2, E ≥ 0.01 MeV) were investigated. Quartz and albite were found to be the major rock-forming minerals, with microcline intermediates, chlorite, and muscovite as the minors. Gamma rays caused no significant changes to the physical properties of the sandstone aggregates, even at high doses (108 MGy). In contrast, neutron irradiation caused alterations that became more pronounced at higher neutron fluences. The solid was confirmed to expand through metamictization of the rock-forming minerals. Quartz and muscovite were the most affected phases, whereas albite and microcline intermediates were only slightly affected, and chlorite was almost unaffected. The decrease in density was measured by He and water pycnometry, and this value was almost reproduced by calculations using the rock-forming mineral composition of the pristine sample measured using X-ray powder diffraction/Rietveld analysis and the cell volume change of the major forming minerals. In addition, light optical microscopy and scanning electron microscopy images confirmed the presence of intergranular and intragranular cracks. Intergranular cracks appeared to have initiated from the quartz grains, which expanded significantly. The intragranular cracks were frequently observed in the albite and microcline intermediates. These cracks can be described as radial cracks starting from the expanding quartz, caused by enforced displacement for deformation consistency with quartz expansion. The crack area ratio quantified by SEM image analysis corresponds to the discrepancy of the volume expansion difference calculated by He or water pycnometry and dimensional change measurements. An evaluation of solid expansion and crack openings in aggregates is important to estimate concrete degradation.
| Original language | English |
|---|---|
| Article number | 154547 |
| Journal | Journal of Nuclear Materials |
| Volume | 583 |
| DOIs | |
| State | Published - Sep 2023 |
Funding
This work was partially supported by the Japanese Concrete Aging Management Program on Irradiation Effects (JCAMP), funded by the Ministry of Economy, Trade, and Industry, Japan. The specimens originated from the project “Advanced aging management technical evaluation of concrete structures in nuclear power plants,” funded by the Nuclear Regulation Authority (NRA, Japan). The work on post-neutron-irradiated samples was realized with the institutional support of the Ministry of Industry and Trade of the Czech Republic. He pycnometry and mass measurements associated to pycnometry were sponsored by the US Department of Energy's (DOEs) Office of Nuclear Energy's Light Water Reactor Sustainability Program under contract DE-AC05- 690 00OR22725 with UT Battelle LLC/Oak Ridge National Laboratory (ORNL) and by the US Department of Energy's (DOEs) Office of Nuclear Energy under the DOE Idaho Operations Office Contract DE-AC07-051D14517 as part of a Nuclear Science User Facilities experiment. Authors would like to express the deepest appreciation to Claudia Aparicio (CVR) for XRD analysis and calculations, Jan Procházka (CVR) for digital image processing and statistical evaluation, and Jan Blažek (The Institute of Information Theory and Automation (UTIA), Czech Academy of Sciences) for crack detection and digital image processing. This work was partially supported by the Japanese Concrete Aging Management Program on Irradiation Effects (JCAMP), funded by the Ministry of Economy, Trade, and Industry, Japan . The specimens originated from the project “Advanced aging management technical evaluation of concrete structures in nuclear power plants,” funded by the Nuclear Regulation Authority (NRA, Japan). The work on post-neutron-irradiated samples was realized with the institutional support of the Ministry of Industry and Trade of the Czech Republic. He pycnometry and mass measurements associated to pycnometry were sponsored by the US Department of Energy's (DOEs) Office of Nuclear Energy's Light Water Reactor Sustainability Program under contract DE-AC05- 690 00OR22725 with UT Battelle LLC/Oak Ridge National Laboratory (ORNL) and by the US Department of Energy's (DOEs) Office of Nuclear Energy under the DOE Idaho Operations Office Contract DE-AC07-051D14517 as part of a Nuclear Science User Facilities experiment. Authors would like to express the deepest appreciation to Claudia Aparicio (CVR) for XRD analysis and calculations, Jan Procházka (CVR) for digital image processing and statistical evaluation, and Jan Blažek (The Institute of Information Theory and Automation (UTIA), Czech Academy of Sciences) for crack detection and digital image processing. This manuscript has been co-authored by UT-Battelle, LLC, under contract DE-AC05–00OR22725 with the US Department of Energy (DOE). The publisher acknowledges the US government license to provide public access under the DOE Public Access Plan ( http://energy.gov/downloads/doe-public-access-plan ).
Keywords
- Density change, crack
- Gamma-ray irradiation
- Neutron irradiation
- Sandstone aggregate, metamictization