High-Level Nuclear Wastes and the Environment: Analyses of Challenges and Engineering Strategies

Abstract

The main objective of this paper is to analyze the current status of high-level nuclear waste disposal along with presentation of practical perspectives about the environmental issues involved. Present disposal designs and concepts are analyzed on a scientific basis and modifications to existing designs are proposed from the perspective of environmental safety. A new concept of a chemical heat sink is introduced for the removal of heat emitted due to radioactive decay in the spent nuclear fuel or high-level radioactive waste, and thermal spikes produced by radiation in containment materials. Mainly, UO 2 and metallic U are used as fuels in nuclear reactors. Spent nuclear fuel contains fission products and transuranium elements which would remain radioactive for 10 4 to 10 8 years. Essential concepts and engineering strategies for spent nuclear fuel disposal are described. Conceptual designs are described and discussed considering the long-term radiation and thermal activity of spent nuclear fuel. Notions of physical and chemical barriers to contain nuclear waste are highlighted. A timeframe for nuclear waste disposal is proposed and time-line nuclear waste disposal plan or policy is described and discussed.

Experimentally and Theoretically Revealing the Co-Doping Effects of Ce–Sr in Gd2Zr2O7

“…One can see that both the density and the hardness show a fluctuation near the incorporation limit. Moreover, the samples show a relatively low density, in the range of 4.22−4.67 g/cm 3 as compared with literature results for Gd 2 Zr 2 O 7 systems (e.g., 4.86 g/cm 3 for Nd 2 Zr 2 O 7 and 6.88 g/cm 3 for GdNdZrZeO 7 ). 58 However, the hardness values (0.92−3.61 GPa) are moderate compared with those of other Gd 2 Zr 2 O 7 based compounds (e.g., 2.09 GPa for Nd 2 Zr 2 O 7 and 5.37 GPa for GdNdZrZeO 7 ).…”

“…With the development of the nuclear industry, the safe disposal of nuclear waste, especially α and β decay fission products, has become imperative and important. − It has attracted a great deal of attention around the word, changing the high-level nuclear waste into a stable host matrix. − The host materials must exhibit excellent performance with respect to physical and chemical properties, i.e., high thermodynamic stability, favorable chemical durability, and good radiation resistance. − …”

Determination of Concrete Vault Thickness of Near Surface Disposal for Radioactive Waste at Serpong Nuclear Area

“…The parameters needed are the properties of soil layers around the vault and the magnitude of the degradation of the concrete based on the variations of infiltration rate [6]. In addition, it should also need to be studied the effects of radiation from the nuclear waste disposal system includes structural effects, thermal effects, the effects of diffusion and hydrological effects on the strength of the concrete vault in the long term period [8].…”

“…Intensive radiation exposure causes the degradation of the structure and strength of the materials that could lead to failure. The effects of radiation from nuclear waste disposal in the system include the effect of causing damage to the structure of the atomic structure, thermal effects that cause chemical reactions and changes in morphology, diffusion effects associated with the movement of radionuclides and hydrological effects associated with groundwater movement [8].…”