CHARACTERIZATION OF A NOVEL NEUTRON SHIELDING MATERIAL CONSISTS OF POLYESTER AND BORON CARBIDE

Ionizing radiation has great benefits to humankind in a wide range of areas such as industry, medical applications, education and R&D fields etc. Beyond these benefits, exposure to excessive radiation doses uncontrollably could cause fatal harms to human body and environment. Radiation types can be named alpha, beta, gamma, neutron radiation and X-rays and all have different characteristics [1]. Among of these, only the neutrons can interact with the nucleus of atoms and change the structure of the nucleus, means a serious danger for living tissues. To ensure safe working conditions, along with distance and time limitations, shielding of the sources is one of the three important parts of As Low as Reasonably Achievable (ALARA) principles. Hence, the shielding material developed and characterized against neutron radiation and analyzed with both experiments and simulations. The basic principle for shielding design against neutron is well known; thermalizing the energetic particles with a good moderator, then absorb them with the second part of the shielding material, which has a high thermal neutron cross section. Polyester is a good moderator due to its high hydrogen content. In addition, it is easy to handle and cost effective matrix material [2]. Therewithal, boron carbide (B4C) has high thermal neutron absorption cross section of 767 barn naturally because of 10B isotope and well known for its hardness and mechanical strength, which makes it a precious material for neutron shielding applications [3]. 10 to 50 wt. % B4C reinforcement 20, 40 and 60 mm-thick specimens were prepared and neutron shielding capabilities of B4C reinforced polyester matrix materials were investigated because of the excellent properties, like nonradioactive capturing of boron carbide against neutron radiation and their characterization were studied with various characterization methods. After metallographic determination of microstructure, impurity analysis and neutron absorption characterizations, it was observed that, shielding capability of the composite material increased with increasing its thickness furthermore when the amount of B4C reinforcement was increased, the shielding rate also increased, but when it was increased up to 40 and 50 %, a slight decrease was observed in the shielding ratio. The simulation of the study, Fluka Monte Carlo (MCNP-5) was made, and experimental data were compared with those obtained by the simulation. The result we find out from this table is; we reached large absorption ratios with our specimens, which contains enriched 10B, “Polyester-B4C” shielding material.