Polymer-Composite Materials for Radiation Protection

Abstract

Paper presents the results of the research of radiation-resistant composites for the bearing and enclosing parts of nuclear plant facilities. The scientific task of the study is to obtain a polymer composite of the maximum attainable density and strength with a given ability to reduce the neutron flux in combination with a high value of the attenuation coefficient of γ-radiation. In order to resolve this task, we developed the composite material based on the polymeric binder with the necessary amount of hydrogen bonds ensuring the capture and moderation of the neutron flux filled with mineral components that absorb γ-radiation. The paper shows the advantage of using non-isocyanate polyurethane as a binder, which is characterized by the presence of a large number of hydrogen bonds providing effective slowing down and capture of “fast” neutrons. Serpentinite, barite, limonite, and magnetite are the materials traditionally used for ‘filling’ in radiation protection are reviewed in the paper. Certain limitations were established when using a non-isocyanate binder, namely, the fillers must satisfy the condition of 8 > pH > 5. In order to ensure the casting method, when constructing the objects made of a radiation-resistant composite, the maximum viscosity of the mixture was limited to 80 Pa∙s, whereas, in order to minimize energy consumption and to prolong the viability of the mixture, the mixing temperature was set at the level of 30 °C. The aforementioned restrictions in the temperature required mechanical-type plasticizer in the polymer mixture, which turns it into the glass powder of ‘sodium-boro-silicate’ composition. The obtained regression equations made it possible to establish a rational combination of a polymeric binder, filler and plasticizer, providing the required degree of radiation protection.