NSUF 18-1453: Electron Tomography Characterisation of Porosity in IG-110 and NBG-17 Nuclear Graphite Grades
Graphite is the moderator material of some Generation IV reactors concepts and British Advanced Gas-cooled Reactors (AGR). Porosity in nuclear graphite influence most of the material properties and evolution of induced neutron irradiation volumetric changes. Mesopores (<0.1 µm) and micropores (<0.001 µm) play a fundamental role on the shrinkage and swelling of graphite. Through the lifetime of a graphite component neutron irradiation generate mesopores and micropores that change CTE values and permeability of the material. These value changes in CTE promote stress concentrations in both VHTR and MSR graphite components and would promote the infiltration of molten salts into the pores. Due to the small nature of these types of pores only high-resolution techniques like electron tomography are capable of detecting voids smaller than 0.1 µm in a 3D space. This novel characterisation technique of mesopores in graphite would help to understand the link between the changes of material properties in irradiated graphite and mesopores. In addition, the characterisation of mesopores will help to understand the possible mechanisms of molten salt intrusion into mesopores.
Furthermore, electron tomography might provide a better understanding of the “grain” like atomic structure of graphite. Imaging in TEM foils indicate the presence of a grain structure of graphite, however, the thickness, and boundaries are difficult to detect with 2D imaging. The 3D reconstructions could provide a different insight on the grain atomic structure of graphite and therefore its possible behaviour under irradiation. The collected data of this project will contribute to the validation and improvement of the polycrystalline model of irradiation behavior developed in the UK by the National Nuclear Laboratory (NNL). This model requires detailed information of the morphology, grain size and porosity of graphite.
Additional Info
| Mező | Érték |
|---|---|
| Awarded Institution | National Nuclear Laboratory |
| Embargo End Date | 2026-02-27 |
| Facility Tech Lead | Kory Linton |
| NSUF Call | FY 2018 RTE 2nd Call |
| PI | Athanasia Tzelepi |
| Project Member | Athanasia Tzelepi, Mrs - National Nuclear Laboratory (https://orcid.org/0000-0001-9534-2377) |
| Project Member | Michael Ward, Materials Scientist - UK National Nuclear Laboratory |
| Project Notes | Awarded on 05/17/2018 |
| Project Type | RTE |
| Publication | Neutron irradiation effects on the microstructure of nuclear graphite TMS2019 2019-03-10 - 2019-03-14 |
| Publication | Electron tomography of unirradiated and irradiated nuclear graphite Michael Ward, Chad Parish, Yutai Katoh, Philip Edmondson, Jose Arregui-Mena Journal of Nuclear Materials 545 2021-01-12 https://www.sciencedirect.com/science/article/abs/pii/S0022311520312575 |
| RTE Number | 1453 |