Study of a “hot” particle with a matrix of U-bearing metallic Zr: Clue to supercriticality during the Chernobyl nuclear accident

The key role of sample analysis in Fukushima Dai-Ichi decommissioning, debris management, and accident progression investigation

“…A comprehensive study of "hot" particles with a non-oxidized matrix of U-bearing metallic Zr (Pöml and Burakov, 2017) and the presence of partly molten nuclear fuel (Pöml and Burakov, 2018) confirmed that local UO 2 -Zr interaction occurred at a very high temperature (>2,850 °C) and probably lasted a few microseconds or less. The presence of Zr-U-Fe-O suggested the melting of the spacer grids and was a clue to the relocation of corium melt with fuel, cladding, and steel components (Shiryaev et al, 2018).…”

“…An overview of recent studies (Shiryaev et al, 2016;Pöml and Burakov, 2017;Zubekhina and Burakov, 2017;Pöml and Burakov, 2018;Shiryaev et al, 2018;Zubekhina et al, 2019;Shiryaev et al, 2020;Zubekhina et al, 2021;Shiryaev et al, 2022;Lönartz et al, 2023) shows that, even after more than 30 years of investigation, Chernobyl sample analysis could contribute additional information about accident progression, conditions of corium and "lava" formation, and the processes of their chemical alteration due to aging. Since the damaged fuel was not removed from the destroyed reactor unit, evaluation of the usefulness of sample analysis results for the fuel debris removal process is not possible.…”

Unresolved challenges in the microanalysis of actinides and nuclear materials

“…European Commission -Joint Research Centre, United States Quantitative x-ray microanalysis is a valuable tool for a wide range of nuclear applications. Typical examples for applications in the field of actinide materials are the analysis of fresh or spent nuclear fuel (post irradiation examination -PIE), the quantification of Pu or Am in materials used in radioisotope thermoelectric generators (RTGs) for space applications (see latest Mars rover Perseverance), or the analysis of materials formed during severe nuclear accidents like Three Mile Island, Chernobyl, and Fukushima [1][2][3].…”

Characterising radium-226 particles from legacy contamination to support radiation dose assessments

“…In these circumstances, data on the source term characteristics, including any radioactive particles present, need to be obtained to undertake an assessment of potential radiation doses against the reference level and take appropriate actions, if necessary. A significant amount of research has been undertaken to characterise radioactive particles from a number of existing exposure situations that have arisen due to past emergencies, events and practices: nuclear power reactor accidents at Chernobyl, Ukraine (Pöml and Burakov, 2017;Shiryaev et al, 2018) and Fukushima, Japan (Kaltofen and Gundersen, 2017;Martin et al, 2016;Yamaguchi et al, 2016); accidents involving nuclear weapons at Palomares, Spain (Aragón et al, 2008;Jimenez-Ramos et al, 2010;Jiménez-Ramos et al, 2012Lind et al, 2007;López et al, 2007;Pöllänen et al, 2006) and Thule, Greenland (Eriksson et al, 2005;Lind et al, 2005); nuclear weapons testing (Burns et al, 1995;Conway et al, 2009;Jernström et al, 2006); the use of depleted uranium in military operations (Lind et al, 2009;Sajih et al, 2010;Salbu et al, 2005Salbu et al, , 2003Török et al, 2004); and legacy contamination from past practices at Sellafield, England (Clacher, 2011(Clacher, , 2010Cowper, 2009), Dounreay (Aydarous et al, 2008;J. Darley et al, 2003) and Dalgety Bay, Scotland (Wilson et al, 2013).…”