Application of Low-Cost Radiation Shielding Material to the Transfer Cask

摘要

Nuclear radiation shielding for the storage, transport and disposal of spent nuclear fuels as well as nuclear waste from weapons production, for nuclear medicine, and other applications is a subject of considerable interest. Extensive research and development efforts are currently underway in this area to reduce costs and create methods for safe handling and transportation of radioactive materials and wastes to ensure worker and public safety. As a part of this effort we present an inventive approach of a very low cost shielding material which has a potential to reduce significantly the cost of handling nuclear waste; the new patented material utilizes ground scrap tire rubber, which is already vulcanized, and particles of inexpensive metals, such as granulated iron or steel. The use of recycled tire rubber provides a market for the cost-effective recycling of used tires. In addition, granulated iron or steel are inexpensive and are readily available as waste products from manufacturing processes. The resulting product provides effective shielding against nuclear radiation at lower cost and usually provides lower overall weight. In the past an interesting concept for shielding within the shipping casks proposed to use depleted uranium (U-238) oxide aggregates combined with binders that will enhance neutron shielding. U-238 is very effective in absorbing gamma rays. The binder materials under consideration include cementitious pastes, pyrolytic carbon and various polymers. The goal is to optimize shielding to maintain cask surface exposures at or below regulatory limits, and at the same time minimize weight and overall container size at economical costs. The main obstacle of the implementation is that chemical interaction occurs between depleted uranium and the concrete, which in our case is not a problem.