Physics-based modelling and validation of inter-granular helium behaviour in SCIANTIX
In this work, we propose a new mechanistic model for the treatment of helium behaviour at the grain boundaries in oxide nuclear fuel. The model provides a rate-theory description of helium inter-granular behaviour, considering diffusion towards grain edges, trapping in lenticular bubbles, and therma...
| Main Authors: | , , , , , , , , |
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| Format: | Article |
| Language: | English |
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Elsevier
2022-07-01
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| Series: | Nuclear Engineering and Technology |
| Subjects: | |
| Online Access: | http://www.sciencedirect.com/science/article/pii/S1738573322000122 |
| _version_ | 1818114880822050816 |
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| author | R. Giorgi A. Cechet L. Cognini A. Magni D. Pizzocri G. Zullo A. Schubert P. Van Uffelen L. Luzzi |
| author_facet | R. Giorgi A. Cechet L. Cognini A. Magni D. Pizzocri G. Zullo A. Schubert P. Van Uffelen L. Luzzi |
| author_sort | R. Giorgi |
| collection | DOAJ |
| description | In this work, we propose a new mechanistic model for the treatment of helium behaviour at the grain boundaries in oxide nuclear fuel. The model provides a rate-theory description of helium inter-granular behaviour, considering diffusion towards grain edges, trapping in lenticular bubbles, and thermal re-solution. It is paired with a rate-theory description of helium intra-granular behaviour that includes diffusion towards grain boundaries, trapping in spherical bubbles, and thermal re-solution. The proposed model has been implemented in the meso-scale software designed for coupling with fuel performance codes SCIANTIX. It is validated against thermal desorption experiments performed on doped UO2 samples annealed at different temperatures. The overall agreement of the new model with the experimental data is improved, both in terms of integral helium release and of the helium release rate. By considering the contribution of helium at the grain boundaries in the new model, it is possible to represent the kinetics of helium release rate at high temperature. Given the uncertainties involved in the initial conditions for the inter-granular part of the model and the uncertainties associated to some model parameters for which limited lower-length scale information is available, such as the helium diffusivity at the grain boundaries, the results are complemented by a dedicated uncertainty analysis. This assessment demonstrates that the initial conditions, chosen in a reasonable range, have limited impact on the results, and confirms that it is possible to achieve satisfying results using sound values for the uncertain physical parameters. |
| first_indexed | 2024-12-11T03:57:46Z |
| format | Article |
| id | doaj.art-b1bfeefe0f2a41ddaaee7846f265fbe2 |
| institution | Directory Open Access Journal |
| issn | 1738-5733 |
| language | English |
| last_indexed | 2024-12-11T03:57:46Z |
| publishDate | 2022-07-01 |
| publisher | Elsevier |
| record_format | Article |
| series | Nuclear Engineering and Technology |
| spelling | doaj.art-b1bfeefe0f2a41ddaaee7846f265fbe22022-12-22T01:21:44ZengElsevierNuclear Engineering and Technology1738-57332022-07-0154723672375Physics-based modelling and validation of inter-granular helium behaviour in SCIANTIXR. Giorgi0A. Cechet1L. Cognini2A. Magni3D. Pizzocri4G. Zullo5A. Schubert6P. Van Uffelen7L. Luzzi8Politecnico di Milano, Department of Energy, Nuclear Engineering Division, via La Masa 34, 20156, Milano, ItalyPolitecnico di Milano, Department of Energy, Nuclear Engineering Division, via La Masa 34, 20156, Milano, ItalyPolitecnico di Milano, Department of Energy, Nuclear Engineering Division, via La Masa 34, 20156, Milano, ItalyPolitecnico di Milano, Department of Energy, Nuclear Engineering Division, via La Masa 34, 20156, Milano, ItalyPolitecnico di Milano, Department of Energy, Nuclear Engineering Division, via La Masa 34, 20156, Milano, ItalyPolitecnico di Milano, Department of Energy, Nuclear Engineering Division, via La Masa 34, 20156, Milano, ItalyEuropean Commission, Joint Research Centre (JRC), Karlsruhe, GermanyEuropean Commission, Joint Research Centre (JRC), Karlsruhe, GermanyPolitecnico di Milano, Department of Energy, Nuclear Engineering Division, via La Masa 34, 20156, Milano, Italy; Corresponding author.In this work, we propose a new mechanistic model for the treatment of helium behaviour at the grain boundaries in oxide nuclear fuel. The model provides a rate-theory description of helium inter-granular behaviour, considering diffusion towards grain edges, trapping in lenticular bubbles, and thermal re-solution. It is paired with a rate-theory description of helium intra-granular behaviour that includes diffusion towards grain boundaries, trapping in spherical bubbles, and thermal re-solution. The proposed model has been implemented in the meso-scale software designed for coupling with fuel performance codes SCIANTIX. It is validated against thermal desorption experiments performed on doped UO2 samples annealed at different temperatures. The overall agreement of the new model with the experimental data is improved, both in terms of integral helium release and of the helium release rate. By considering the contribution of helium at the grain boundaries in the new model, it is possible to represent the kinetics of helium release rate at high temperature. Given the uncertainties involved in the initial conditions for the inter-granular part of the model and the uncertainties associated to some model parameters for which limited lower-length scale information is available, such as the helium diffusivity at the grain boundaries, the results are complemented by a dedicated uncertainty analysis. This assessment demonstrates that the initial conditions, chosen in a reasonable range, have limited impact on the results, and confirms that it is possible to achieve satisfying results using sound values for the uncertain physical parameters.http://www.sciencedirect.com/science/article/pii/S1738573322000122Helium behaviourOxide nuclear fuelMeso-scale modellingFuel performance codesSCIANTIX |
| spellingShingle | R. Giorgi A. Cechet L. Cognini A. Magni D. Pizzocri G. Zullo A. Schubert P. Van Uffelen L. Luzzi Physics-based modelling and validation of inter-granular helium behaviour in SCIANTIX Nuclear Engineering and Technology Helium behaviour Oxide nuclear fuel Meso-scale modelling Fuel performance codes SCIANTIX |
| title | Physics-based modelling and validation of inter-granular helium behaviour in SCIANTIX |
| title_full | Physics-based modelling and validation of inter-granular helium behaviour in SCIANTIX |
| title_fullStr | Physics-based modelling and validation of inter-granular helium behaviour in SCIANTIX |
| title_full_unstemmed | Physics-based modelling and validation of inter-granular helium behaviour in SCIANTIX |
| title_short | Physics-based modelling and validation of inter-granular helium behaviour in SCIANTIX |
| title_sort | physics based modelling and validation of inter granular helium behaviour in sciantix |
| topic | Helium behaviour Oxide nuclear fuel Meso-scale modelling Fuel performance codes SCIANTIX |
| url | http://www.sciencedirect.com/science/article/pii/S1738573322000122 |
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