Question

What is meant by nuclear waste?

Answer 1

Hint: Nuclear reactors, fuel processing factories, hospitals, and research institutions all produce radioactive (or nuclear) waste as a byproduct. Decommissioning and dismantling nuclear reactors and other nuclear installations generates radioactive waste. There are two types of waste: high-level and low-level trash.

Complete answer:
A form of hazardous trash that contains radioactive substances is known as radioactive waste. Many operations, such as nuclear medicine, nuclear research, nuclear power generation, rare-earth mining, and nuclear weapons reprocessing, produce radioactive waste. Government authorities control the storage and disposal of radioactive waste in order to safeguard human health and the environment. It is divided into three categories: low-level waste (LLW), which contains small amounts of mostly short-lived radioactivity, intermediate-level waste (ILW), which contains higher amounts of radioactivity and requires some shielding, and high-level waste (HLW), which is highly radioactive and hot due to decay heat, and thus requires cooling and shielding. Approximately 96 percent of spent nuclear fuel is recycled into uranium-based and mixed-oxide (MOX) fuels at nuclear reprocessing plants. Fission products, which are extremely radioactive High-Level Waste, account for the remaining $4\%$. Because the radioactivity of this material gradually diminishes with time, it is kept in suitable disposal facilities until it no longer poses a hazard. The amount of time that radioactive waste must be kept varies according to the kind of waste and radioactive isotopes. A large amount of radioactive waste is made up of a variety of radionuclides, which are unstable isotopes of elements that decay and generate ionising radiation, which is dangerous to humans and the environment. Different isotopes produce various types and quantities of radiation that persist for varying amounts of time. All radioactive waste loses its radioactivity over time.

Note:
The half-life of all radionuclides in the waste is the time it takes for half of the atoms to decay into another nuclide. All radioactive waste eventually decays into non-radioactive elements (i.e., stable nuclides). The rate of decay is inversely related to the period of decay because radioactive decay follows the half-life rule. In other words, the radiation from a long-lived isotope such as iodine-129 will be significantly less than that from a short-lived isotope such as iodine-131. The two tables show some of the most common radioisotopes, their half-lives, and radiation production as a percentage of uranium-235 fission yield.