Electron-Sputtering-Induced Spontaneous Dust Productivity and Radiation Steadiness of Silicate Compositions Containing the Irradiated Nuclear Fuel

Abstract

Behaviour of silicate compositions containing irradiated nuclear fuel, so-called lava-like fuel-containing materials (LFCM), which had been formed as a product of heavy nuclear accident on Chernobyl NPP 4-th Unit in 1986, have been under both the theoretical and workbench investigation. Recent experimental studies indicate, that LFCM and irradiated fuel surface does produce a submicronic radioactive dust spontaneously, i.e. without any external action. The non-contradicting quantitative explanation of observed phenomenon (giant sputtering yield) can be provided when taking into account an electron sputtering mechanism associated with Coulomb explosions, which occur intensively both just beneath a surface of materials under study and inside its volume as well. The last circumstance leads to necessity to reexamine the level of radiation damages in solids containing a large volume concentration of alpha- and beta-emitters in both. In principle, the observed phenomena must be of universal character for all high-radioactive dielectrics, but quantitative characteristics prognosis of its steadiness does depend on initial structure and properties of material. As for LFCM, it has been estimated by computer modeling based on a method of molecular dynamics (MD). The main outcome is the glass matrix cannot serve as a reliable material appointed for alpha radwaste immobilization. A submicronic radioactive dust have been already identified in the destroyed 4-th Unit premises in a large quantities; its regular pollutions in environment represents not a local, but the global problem due to a very special features concerning submicronic dust dissemination in environment.