High-Energy Tritium Ion and α-Particle Release from the Near-Surface Layer of Lithium During Neutron Irradiation in the Nuclear Reactor Core

This paper examines in situ spectroscopic measurements of nuclear-excited plasma of noble gases excited by ⁶Li(n,α)³H nuclear reaction products in the core of a nuclear reactor. A thin layer of lithium applied on the walls of the experimental device, stabilized in the matrix of the capillary-porous structure, serves as a source of gas excitation. During in-pile tests conducted at the IGR research reactor, thermal neutrons interact via the ⁶Li(n,α)³H reaction, and the emergent α-particles with a kinetic energy of 2.05 MeV and tritium ions with a kinetic energy of 2.73 MeV excite the noble gas (Ar) medium. The intensity of tritium release from the lithium layer in noble gases was estimated by the intensity of the α-line of the Balmer series of the tritium atom ³H_α (656.2 nm). A tritium release was observed at 710 K due to the beginning of desorption of thermalized tritium atoms dissolved in the liquid phase of lithium. The results are of interest in terms of clarifying the mechanisms and developing models that allow for describing the processes of generation, diffusion, and release of tritium from lithium during neutron irradiation.