Products of molten corium-metal interaction in chernobyl accident: Composition and leaching of radionuclides

Evolution of Chernobyl Corium in Water: Formation of Secondary Uranyl Phases

“…The Chernobyl corium-containing sample used in this research is a product of high temperature co-melting of U-oxide fuel, zircaloy cladding, steel, serpentine and concrete [ 4 ]. As a result, it has a unique and complex chemical and phase compositions.…”

“…Thus, one can assume that the initial chemical forms of uranium are less important in most cases for the formation of these phases than particular oxidizing conditions and properties of the environment [ 71 , 72 , 73 , 74 , 75 , 76 , 77 ]. Corium, which possibly formed at F-1 NPP may differ chemically from Chernobyl corium [ 4 , 10 , 78 ], but the products of its alteration in water would be similar.…”

“…The Chernobyl corium-containing sample ( Figure 1 ) consisted of mainly Fe 3 O 4 and inclusions of solid solutions “UO 2 -ZrO 2 ” (i.e., corium solidification products) with a broad range of U/Zr ratio and was used for chemical alteration experiment in distilled water at 150 °C for one year. Details about chemical and phase composition of this sample have been reported before [ 4 ]. The main interest to study this particular type of Chernobyl highly radioactive sample is related to evaluating of physico-chemical durability of corium–steel interaction products over a long time in water under increased temperature.…”

“…Products of corium formation and solidification in the form of solid solutions “UO 2 -ZrO 2 ” with different U/Zr ratio were identified in the matrices of so-called Chernobyl “lava” and “hot” particles [ 2 , 3 ]. In addition, corium products were discovered recently in the matrix of an unusual material which consisted of mainly molten and oxidized steel [ 4 ]. Such a material was formed during an initial very high-temperature (at least 2400–2600 °C) stage of the accident and it was injected into room 305/2 (right below the reactor core) where it rapidly solidified without interaction with silicate construction material (serpentine and concrete).…”

“…Herein, we report the results of precise phase identifications of two uranyl compounds, which were formed on the surface of the Chernobyl sample collected in room 305/2 of the Chernobyl “Shelter” [ 4 ] and used in previous experiments on hydrochemical alteration [ 10 ]. New-formed phases were characterized using several experimental techniques including Single-Crystal X-ray Diffraction Analysis (SCXRD) as well as optical and scanning electron microscopy.…”