NSUF 16-870: In situ ion irradiation and high resolution microstructure and microchemistry analysis of accident tolerant fuels
Project objectives: Because of its use as the preferred nuclear fuel cladding material since the 1950s, a great deal of effort has been exerted in improving the performance of zirconium cladding alloys at temperatures of 300 ± 60 °C in pressurised water. However, recent Fukushima accident which was related with Zr melting in the reactor and releasing hydrogen in severe condition led to further development of accident tolerant fuel claddings, including the ones will be used in this proposal: multilayer TiAlN and TiN ceramic coatings on ZIRLO® coupons. The specimens used in this study is produced by cathodic arc physical vapor deposition (CA-PVD) with multilayer TiAlN and TiN ceramic coatings on ZIRLO® coupons. Several architecture types are created 2-layer, 4-layer, 8-layer and 16-layer layers. Initial corrosion testing in static pure water of these samples was done at at 360°C and 18.7 MPa for up to 90 days and it showed no spallation/delamination. The corrosion performance is also six times smaller than uncoated ZIRLO®. However, there is no current irradiation data for this design, thus irradiation experiments are needed in order to investigate the radiation damage performance of this design. In situ ion irradiation of samples will be tested in the IVEM facility which provides a better understanding of materials irradiation performance and a clearer guideline for selecting sample for further neutron irradiation experiment which will be performed at the Halden research reactor. Experiment details: In this proposal, we’ll be conducting in situ ion irradiation on carefully prepared TEM thin foils in order to provide better understanding of its irradiation performance. Two different types of TEM samples will be produced in this study: both cross section and top to bottom view sample. Careful preparation of cross section TEM sample will be done by in situ FIB lift out, containing both the layered structure of TiAlN/TiN and Zr matrix will be used in this study. Top to bottom view specimen of the sample will be made from sample polishing and PIPS II thinning. We are planning to use 1 MeV Kr ions up to a dose rate range up to 10^12 ions/cm2/sec to irradiate thin TEM foils of ATF up to 20 dpa, at a temperature from room temperature up to 360°C. Real time recording of defect nucleation and evolution will be captured on the high speed CCD camera with 200 frames/second, so is their number density and size distribution. 3D reconstruction of all the sample defects will be generated using a rotating holder which will give a comprehensive visualisation of the coating/matrix interface morphology and defects distribution. Samples will also be studied using an environmental cell holder which allows corrosion at elevated temperatures up to 700°C to occur in between TEM imaging. Post-irradiation samples will also be studied using the state-of-the-art microscopes at the Electron Microscopy Center in ANL. Microstructure and microchemistry of the samples will be examined by TEM, STEM, EDX and EELS, which provides a complimentary view of the samples. We will examine the shape, size and crystallographic texture of grains in the matrix and coating grains, the influence of second phase particles (SPPs), cracking, nano-scale porosity and the local chemistry of the coating-matrix interface. Project timeline: This project will last for six months. Initial preparation of samples will take one to one and a half months, followed by two one-week microscope times on the IVEM facility, separated by two months. In between the sessions, ex situ microscopy work will be performed. By the end of the six months, we are expecting to see the initial results of its irradiation performance comparing with uncoated Zr claddings and help to narrow down the selection of neutron irradiation experiment.
Additional Info
| Field | Value |
|---|---|
| Abstract | Project objectives: Because of its use as the preferred nuclear fuel cladding material since the 1950s, a great deal of effort has been exerted in improving the performance of zirconium cladding alloys at temperatures of 300 ± 60 °C in pressurised water. However, recent Fukushima accident which was related with Zr melting in the reactor and releasing hydrogen in severe condition led to further development of accident tolerant fuel claddings, including the ones will be used in this proposal: multilayer TiAlN and TiN ceramic coatings on ZIRLO® coupons. The specimens used in this study is produced by cathodic arc physical vapor deposition (CA-PVD) with multilayer TiAlN and TiN ceramic coatings on ZIRLO® coupons. Several architecture types are created 2-layer, 4-layer, 8-layer and 16-layer layers. Initial corrosion testing in static pure water of these samples was done at at 360°C and 18.7 MPa for up to 90 days and it showed no spallation/delamination. The corrosion performance is also six times smaller than uncoated ZIRLO®. However, there is no current irradiation data for this design, thus irradiation experiments are needed in order to investigate the radiation damage performance of this design. In situ ion irradiation of samples will be tested in the IVEM facility which provides a better understanding of materials irradiation performance and a clearer guideline for selecting sample for further neutron irradiation experiment which will be performed at the Halden research reactor. Experiment details: In this proposal, we’ll be conducting in situ ion irradiation on carefully prepared TEM thin foils in order to provide better understanding of its irradiation performance. Two different types of TEM samples will be produced in this study: both cross section and top to bottom view sample. Careful preparation of cross section TEM sample will be done by in situ FIB lift out, containing both the layered structure of TiAlN/TiN and Zr matrix will be used in this study. Top to bottom view specimen of the sample will be made from sample polishing and PIPS II thinning. We are planning to use 1 MeV Kr ions up to a dose rate range up to 10^12 ions/cm2/sec to irradiate thin TEM foils of ATF up to 20 dpa, at a temperature from room temperature up to 360°C. Real time recording of defect nucleation and evolution will be captured on the high speed CCD camera with 200 frames/second, so is their number density and size distribution. 3D reconstruction of all the sample defects will be generated using a rotating holder which will give a comprehensive visualisation of the coating/matrix interface morphology and defects distribution. Samples will also be studied using an environmental cell holder which allows corrosion at elevated temperatures up to 700°C to occur in between TEM imaging. Post-irradiation samples will also be studied using the state-of-the-art microscopes at the Electron Microscopy Center in ANL. Microstructure and microchemistry of the samples will be examined by TEM, STEM, EDX and EELS, which provides a complimentary view of the samples. We will examine the shape, size and crystallographic texture of grains in the matrix and coating grains, the influence of second phase particles (SPPs), cracking, nano-scale porosity and the local chemistry of the coating-matrix interface. Project timeline: This project will last for six months. Initial preparation of samples will take one to one and a half months, followed by two one-week microscope times on the IVEM facility, separated by two months. In between the sessions, ex situ microscopy work will be performed. By the end of the six months, we are expecting to see the initial results of its irradiation performance comparing with uncoated Zr claddings and help to narrow down the selection of neutron irradiation experiment. |
| Award Announced Date | 2016-12-16T07:49:14.043 |
| Awarded Institution | Center for Advanced Energy Studies |
| Facility | Microscopy and Characterization Suite |
| Facility Tech Lead | Wei-Ying Chen, Yaqiao Wu |
| Irradiation Facility | None |
| PI | Jing Hu |
| PI Email | [email protected] |
| Project Type | RTE |
| RTE Number | 870 |