Low-level nuclear waste has low radioactivity and comes from various activities, while high-level waste is highly radioactive and mainly from spent fuel.
Understanding Low-Level and High-Level Nuclear Waste
Nuclear power plants and other facilities generate radioactive waste, which is classified into two main categories: low-level and high-level waste. This article will explain the differences between these types of nuclear waste, including their sources, radioactivity levels, and disposal methods.
Low-Level Nuclear Waste (LLW)
- Sources: Low-level waste is produced from a variety of activities, including nuclear power generation, medical procedures, research laboratories, and industrial processes. Common examples of LLW include contaminated protective clothing, tools, and filters.
- Radioactivity: LLW typically contains small amounts of radioactivity, and its half-life, the time required for half of the radioactive atoms to decay, is generally less than 30 years. However, some LLW might have longer half-lives.
- Disposal: LLW is often compacted or incinerated to reduce its volume, then placed in containers and buried in shallow landfills. Some facilities use engineered structures called near-surface disposal facilities, designed to contain the waste and prevent the release of radioactive materials.
High-Level Nuclear Waste (HLW)
- Sources: High-level waste is primarily generated from nuclear reactor fuel that has been used and is no longer efficient in sustaining a nuclear reaction. This spent nuclear fuel contains highly radioactive materials, such as fission products and transuranic elements.
- Radioactivity: HLW is characterized by its high radioactivity and long half-life, which can range from several tens to hundreds of thousands of years. Due to its potential health and environmental risks, proper disposal of HLW is crucial.
- Disposal: HLW is typically stored in cooling pools or dry casks at nuclear power plants for a certain period to reduce its radioactivity and heat generation. Ultimately, the preferred method for HLW disposal is deep geological repositories, which provide long-term isolation from the biosphere.
In summary, the main differences between low-level and high-level nuclear waste lie in their sources, radioactivity levels, and disposal methods. While low-level waste is generated from various activities and contains relatively low radioactivity, high-level waste results from spent nuclear fuel and is highly radioactive. Low-level waste is typically disposed of in shallow landfills or near-surface facilities, whereas high-level waste is stored temporarily before being placed in deep geological repositories.