NSUF 16-682: Destructive Examination of Metallic Fuel Elements Subjected to Transient Irradiation
A unique transient irradiation experiment was conducted during one of the last operating cycles of the EBR-II to evaluate the off-normal response of metallic fuel designs. A full EBR-II subassembly (X512) was loaded with 19 well-characterized ternary and binary metal fuel elements that had previously been irradiated to burnups between 5 and 11% (primarily in X441). These pins were subjected to a 30% transient overpower with a 0.1% (dP/P)/s ramp rate. PIE was only partially completed on these elements due to cancellation of the IFR project. All non-destructive examinations (including neutron radiography, gamma scanning, and profilometry) were completed. However, destructive examination of only one element was performed. The key fuel elements are currently retained in HFEF. Destructive analysis including plenum gas pressure and optical microscopy of three additional elements is required to fully interpret the fuel response of the fuel designs to this event.During the transient, significant heating of the fuel alloy will occur resulting in thermal expansion and microstructural changes that could induce cladding deformation and, potentially, breach. Post-irradiation non-destructive examinations are conducted to identify any permanent deformation to the cladding or the fuel column. These examinations have been completed on all elements and included neutron radiography (to evaluate fuel column expansion), gamma scanning (fuel column expansion and fission product transport), and profilometry (to evaluate cladding strain). Destructive examination is conducted to identify microstructural changes that may have driven the macroscopic behavior of the fuel. Destructive examination was only completed on one element from the experiment. This project will complete destructive examination of the three additional elements including GASR analysis and optical microscopy. Elements DP-55 (U-19Pu-10Zr, 75% smear density, 11.1% BU, 2.1 P/F ratio), DP-49 (U-19Pu-10Zr, 85% smear density, 9.8% BU, 1.5 P/F ratio), and J559 (U-10Zr, 75% smear density, 9.2% BU, 1.5 P/F ratio) have been selected for further analysis.The data collected in this project will be used to establish a one-of-a-kind fuel performance benchmark case for fast reactor metallic fuel designs under operational transient conditions. Benchmark cases like this are required to validate advanced modeling and simulation codes for fuel performance. In particular, the key fast reactor fuel performance phenomena during transient operation were recently incorporated into the BISON code by a project team member (including FCCI, transient fission gas release, etc.) that must be validated. The simplicity of this event make it an ideal case study (to be followed by the more complex high ramp rate transients conducted in TREAT).
Additional Info
| Field | Value |
|---|---|
| Abstract | A unique transient irradiation experiment was conducted during one of the last operating cycles of the EBR-II to evaluate the off-normal response of metallic fuel designs. A full EBR-II subassembly (X512) was loaded with 19 well-characterized ternary and binary metal fuel elements that had previously been irradiated to burnups between 5 and 11% (primarily in X441). These pins were subjected to a 30% transient overpower with a 0.1% (dP/P)/s ramp rate. PIE was only partially completed on these elements due to cancellation of the IFR project. All non-destructive examinations (including neutron radiography, gamma scanning, and profilometry) were completed. However, destructive examination of only one element was performed. The key fuel elements are currently retained in HFEF. Destructive analysis including plenum gas pressure and optical microscopy of three additional elements is required to fully interpret the fuel response of the fuel designs to this event.During the transient, significant heating of the fuel alloy will occur resulting in thermal expansion and microstructural changes that could induce cladding deformation and, potentially, breach. Post-irradiation non-destructive examinations are conducted to identify any permanent deformation to the cladding or the fuel column. These examinations have been completed on all elements and included neutron radiography (to evaluate fuel column expansion), gamma scanning (fuel column expansion and fission product transport), and profilometry (to evaluate cladding strain). Destructive examination is conducted to identify microstructural changes that may have driven the macroscopic behavior of the fuel. Destructive examination was only completed on one element from the experiment. This project will complete destructive examination of the three additional elements including GASR analysis and optical microscopy. Elements DP-55 (U-19Pu-10Zr, 75% smear density, 11.1% BU, 2.1 P/F ratio), DP-49 (U-19Pu-10Zr, 85% smear density, 9.8% BU, 1.5 P/F ratio), and J559 (U-10Zr, 75% smear density, 9.2% BU, 1.5 P/F ratio) have been selected for further analysis.The data collected in this project will be used to establish a one-of-a-kind fuel performance benchmark case for fast reactor metallic fuel designs under operational transient conditions. Benchmark cases like this are required to validate advanced modeling and simulation codes for fuel performance. In particular, the key fast reactor fuel performance phenomena during transient operation were recently incorporated into the BISON code by a project team member (including FCCI, transient fission gas release, etc.) that must be validated. The simplicity of this event make it an ideal case study (to be followed by the more complex high ramp rate transients conducted in TREAT). |
| Award Announced Date | 2016-08-16T00:00:00 |
| Awarded Institution | None |
| Facility | None |
| Facility Tech Lead | Yaqiao Wu |
| Irradiation Facility | None |
| PI | Daniel Wachs |
| PI Email | [email protected] |
| Project Type | RTE |
| RTE Number | 682 |