Development and Performance of New Gadolinium and Boron Containing Radiation-Absorbing Composite Systems

The theoretical design and the experimental design and development of multifunctional radiation-absorbing composite material systems based on gadolinium, boron, and tungsten has been carried out. Based on theoretical calculations, the effective compositions of these composite subsystems were established for the enhanced absorption of neutron and gamma irradiation in various energy spectra. In addition, the systems and systems compositions were designed and processed for enhanced multifunctional performance. Selected and optimized compositions of Gd-B-W system were densified by shock wave consolidation technology. The technological parameters for the explosive consolidation processes and the structure-properties relationships are presented and discussed. The radiation-absorbing properties of the bulk samples were investigated and measured under neutron and gamma irradiation. The theoretical design and the optimization of these composite systems were carried out by the Monte Carlo method with a GEANT 3 program, which contained a special GCALOR package for the simulation of the interaction of thermal and fast neutrons with the composite material systems. During the neutron passage through the samples, the main processes of the interaction of neutrons with matter were considered including elastic and inelastic scattering, neutron fission of nuclei, and radiation capture. The attenuation factor of the irradiation flux is determined as a criterion of efficiency of radiation absorption. For the energy of 0.025 eV (thermal neutrons), gadolinium-containing composites have the maximum absorption capability. In the range of energy spectrum from 1 eV to 10 eV, the boron-containing composites have better absorption performance. For the capture of neutrons in wide energy spectrum, the (n, gamma) reaction takes place and tungsten provides enhanced absorption of radiation. In the presence of mixed radiation sources (neutron and gamma quanta), the boron- and gadolinium-containing composite materials prepared on the tungsten basis have the best performance. In addition to enhanced radiation absorption properties, these composite systems show also enhancement on other properties such as corrosion resistance in aggressive media.