Year
2011
Abstract
TN International has developed a new family of neutron shielding materials for transport/storage casks and installations meeting the needs of the market (high shielding capabilities and high temperature resistance). These materials are composed of mineral fillers (alumina hydrate, zinc borate) and a thermosetting resin such as polyester or vinylester. The polymerization of this mixture leads to a rigid three-dimensional lattice solid showing safe behaviour under hypothetical accident conditions (shielding/attenuation efficiency is compliant with nuclear site specification, and in case of transport in compliance with IAEA safety standards TS-R-1). Different tests have been performed on the neutron shielding materials showing a good radiation and heat resistance during the period considered: storage (40 years) or transport (depending of transport frequency). They are also fire resistant with self extinguishing property. The quality and homogeneity of the shielding material have been proven. The shielding ability for neutron radiation is directly related to high content of hydrogen (for slowing down neutrons) and boron (for absorbing neutrons). Hydrogen is brought by the organic matrix (resin) and alumina hydrate leading to a typical content of 5.10 22 at/cm 3 . Boron is brought by zinc borate leading to a content of 9.10 20 at/cm 3 . Accelerated tests at different temperatures (100°C to 170°C) were performed to determine the temperature resistance of these materials. According to these tests, neutron shielding materials developed by TN International can be used long term at the maximal temperature of 160°C.