INFLUENCE OF DIFFERENT NATURAL FIBER-BASED COMPOSITES USE AS A FILLER FOR CRACKING IN NUCLEAR REACTOR BIOLOGICAL SHIELDS

Abstract

The biological shield is very important in the nuclear power reactor, so it is necessary to study the effect of crack on it. This work aims to study fiber composites as a radiation shielding for various purposes associated with nuclear installations, as properly as a repairing mixture for developing cracks in the biological shields of a nuclear power reactor. In this study, the MCNP-5 model of a pressurized water reactor (PWR) was used. Four different fiber composites of natural fiber (FP) (ρ= (1.373 g/ m3), fiber with lead (FPPb) (ρ=2.756 g /cm3), cement fiber (CF) (ρ=2.095 g/ m3) and cement-fiber-magnetite (CFM) (ρ =2.858 g /cm3) were used as the filler materials for cracking in the biological shield. The total mass attenuation coefficients µm for the studied composites have been calculated by the Win X-Com program of gamma-ray at an energy range from 0.15 – 20 MeV. Neutron and gamma-ray fluxes and dose rates were calculated through different distances of the reactor shields for different fiber composites. Total dose rates through biological shield without cracking and after cracking have been calculated. Radiation Protection Efficiency (RPE %) for all samples at the outer surface of the biological shield was calculated. The results showed that by using fiber composites as a filler for cracking, the values of flux and dose rate for neutrons and gamma-rays have decreased. Also, FPPb is the best material for gamma-ray because it contains lead, which has a high atomic number. While CFM has the best material shield for neutron and gamma-ray in addition to magnetite and boron carbide the properties of CFM composite were improved. Max. value of RPE % for FPPb was (43.1%), then CFM (37.2%), Fp (30.2%) and CF (20.2%). From these results, it can be concluded that plastic fiber composites were the best materials that can be used as a filler in the biological shield of nuclear power reactors.