| Article | |
| Title | Identifying Thermodynamic Mechanisms Affecting Reactor Pressure Vessel Integrity During Severe Nuclear Accidents Simulated by Laser Heating at the Laboratory Scale |
| Author(s) | Athanasakis-Kaklamanakis, Michail (CERN ; Leuven U.) ; Manara, Dario ; Vlahovic, Luka ; Robba, Davide ; Boboridis, Konstantinos ; Ernstberger, Markus ; Eloirdi, Rachel ; Amador, Pedro ; Konings, Rudy J.M. |
| Publication | 2023 |
| Imprint | 2023 |
| Number of pages | 17 |
| In: | Nucl. Sci. Eng. 197 (2023) 381-397 |
| DOI | 10.1080/00295639.2022.2108643 |
| Abstract | n this work, laser heating is used to experimentally investigate the high-temperature behavior of the U-Fe-Zr-O system using arc-melted samples with various nominal compositions. Three-phase transitions are observed in the vicinity of 1100, 1700, and 2200 K. Principal component analysis of the phase transition temperatures in the course of laser-heating thermal cycling indicates that the phase transition around 1100 K is driven by the interaction of stainless steel (SS) with metallic U, the phase transition around 1700 K by the melting of stainless steel, and the phase transition above 2000 K by the eutectic melting of UO2. The results also reveal two hitherto overlooked interactions in the U-Fe-Zr-O system, which could have severe consequences for the contain-ment of corium inside the reactor pressure vessel (RPV). First, the phase transition temperatures of the samples varied extensively as a result of the laser-driven rapid thermal cycling. Variations of up to 390 K were observed in the phase transition temperatures, suggesting that depending on the initial conditions of corium formation, the corium-driven ablation of the RPV wall could commence significantly earlier than the current state-of-the-art severe accident codes would predict. Additionally, evidence of a large exothermic reaction between zirconium and molten steel was observed upon SS melting. Such phenomenon may also be driven by material segregation during fast heating and cooling. If such a mechanism is activated during a severe nuclear accident, it can have an important impact on the overall thermal balance of the RPV. |
| Copyright/License | Publication: © 2022-2024 The Author(s) (License: CC-BY-NC-ND-4.0) |
Record created 2024-03-13, last modified 2024-09-25
