NSUF 20-4206: Investigation of the effects of neutron irradiation on minerals of concrete aggregates

Concrete provides structural support and acts as a biological shield of the Light Ware Reactors (LWR). It can be considered a composite material formed by cement paste, aggregates and other features such as pores and cracks. Multiple degradation mechanisms affect the structural integrity of concrete by promoting the cracking and deterioration of mechanical properties. As part of the reactor environment, neutron irradiation produces swelling of the aggregates. This phenomenon is known as Radiation Induced Volumetric Expansion (RIVE). The expansion of the aggregates produced by irradiation is believed to be driven by the amorphization of the crystal structure of the minerals. In order to study RIVE, the authors propose to study the RIVE effect at the atomic level in neutron irradiated aggregates. Transmission Electron Microscopy (TEM) techniques will be used to quantify the degree of amorphization produced by neutron irradiation A TEM foil will be obtained from each mineral, this will facilitate the experimental procedures and also would help to directly compare the irradiated and pristine samples. TEM analysis will be performed in all the samples to measure the structural changes produced by the irradiation using the JEOL JEM 2100F TEM operated at 80 kV to reduce possible electron beam damage. Firstly, high resolution images will be taken to measure the deformation of the crystal structure and secondly Selective Area Electron Diffraction (SAED) patterns will be acquired to validate the TKD measurements. Additional EELS scans will be performed to compare the bonding structure of as-received samples and neutron irradiated samples. This will help to build a methodology to study the RIVE effect in other minerals or rocks commonly found in concrete. This fundamental understanding will help to determine the structural changes that promote RIVE and possible identification of aggregates less sensitive to the radiation damage.

Additional Info

Field	Value
Abstract	Concrete provides structural support and acts as a biological shield of the Light Ware Reactors (LWR). It can be considered a composite material formed by cement paste, aggregates and other features such as pores and cracks. Multiple degradation mechanisms affect the structural integrity of concrete by promoting the cracking and deterioration of mechanical properties. As part of the reactor environment, neutron irradiation produces swelling of the aggregates. This phenomenon is known as Radiation Induced Volumetric Expansion (RIVE). The expansion of the aggregates produced by irradiation is believed to be driven by the amorphization of the crystal structure of the minerals. In order to study RIVE, the authors propose to study the RIVE effect at the atomic level in neutron irradiated aggregates. Transmission Electron Microscopy (TEM) techniques will be used to quantify the degree of amorphization produced by neutron irradiation A TEM foil will be obtained from each mineral, this will facilitate the experimental procedures and also would help to directly compare the irradiated and pristine samples. TEM analysis will be performed in all the samples to measure the structural changes produced by the irradiation using the JEOL JEM 2100F TEM operated at 80 kV to reduce possible electron beam damage. Firstly, high resolution images will be taken to measure the deformation of the crystal structure and secondly Selective Area Electron Diffraction (SAED) patterns will be acquired to validate the TKD measurements. Additional EELS scans will be performed to compare the bonding structure of as-received samples and neutron irradiated samples. This will help to build a methodology to study the RIVE effect in other minerals or rocks commonly found in concrete. This fundamental understanding will help to determine the structural changes that promote RIVE and possible identification of aggregates less sensitive to the radiation damage.
Award Announced Date	2020-07-14T14:16:20.367
Awarded Institution	None
Facility	None
Facility Tech Lead	Kory Linton
Irradiation Facility	None
PI	Matheus Araujo Tunes
PI Email	[email protected]
Project Type	RTE
RTE Number	4206