Fabrication of Beta-Active Carbon Nano-Layer Using Ion-Plasma Technology for Irradiated Reactor Graphite Deactivation

In this paper we present ion-plasma deactivation technology for the decontamination of irradiated reactor graphite and the simultaneous extraction of the dose-forming isotope <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">14</sup>C in the form of a useful product – a beta-active nano-layer. Ion-plasma deactivation technology is based on the using of a “short” discharge in an inert gas environment (argon) and allows for the compact extraction of the <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">14</sup>C isotope from the surface of RBMK reactor graphite blocks. The extraction of the <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">14</sup>C isotope is carried out by processing graphite blocks in in argon “short” discharge in, namely by argon ion sputtering of the graphite blocks surface layer enriched with <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">14</sup>C isotope. Operating parameters of ion-plasma technology: pressure 0.1-1 atm., voltage 200-1000 V, discharge current 0.001-1 A/cm<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup>, discharge gap 0.1-3 mm. The deposition of the sputtered layer of 14C is realized in the diffusion mode on the metal electrode-collector surface in the solid form. The fabricating of solid deposit containing the isotope can be used, for example, in nuclear medicine and for the creating of beta-voltaic batteries based on the beta emitter isotope <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">14</sup>C. In our experiment, deposited carbon layers (beta-active nano/microlayer) of different thicknesses were obtained on nickel electrode collector during the process of sputtering reactor graphite at different plasma discharge exposure times. Extracted <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">14</sup>С isotope can be used for the fabrication of beta-active layer inside of "nano-micro-sandwich" for the manufacturing of “eternal” energy sources – a new vacuum-beta-cell (VBC).