Low-level Waste vs High-level Waste

radioactive contamination

Radioactive waste is any waste that contains radioactive material. Radioactive (or nuclear) waste is a byproduct from nuclear reactors, fuel processing plants, hospitals, various industrial applications and research facilities. Radioactive waste is hazardous to most forms of life and the environment, and is regulated by government agencies in order to protect human health and the environment.

Low-level Waste and High-level Waste

As was written, radioactive waste is any waste that contains radioactive material. This material is either intrinsically radioactive, or has been contaminated by radioactive material, and that is deemed to have no further use. Basic classification is based on the intensity (specific activity) of a material.

  • Low-level Waste. Low-level waste, LLW, comes from reactor operations and from medical, academic, industrial, and other commercial uses of radioactive materials. Low-level wastes include paper, rags, tools, clothing, filters, and other materials which contain small amounts of mostly short-lived radioactivity. Low-level waste (LLW) has a radioactive content not exceeding 4 giga-becquerels per tonne (GBq/t) of alpha activity or 12 GBq/t beta-gamma activity. LLW usually does not require shielding during handling and transport, most LLW is suitable for shallow land burial. To reduce its volume, it is often compacted or incinerated before disposal.
  • High-level Waste. High-level waste, HLW,  is primarily spent fuel removed from reactors after producing electricity. HLW is also a type of nuclear waste created by the reprocessing of spent nuclear fuel (e.g. waste formed by vitrification of liquid high-level waste). High-level waste is sufficiently radioactive for its decay heat (>2kW/m3) to increase its temperature, and the temperature of its surroundings, significantly. As a result, high-level waste requires cooling and sufficient shielding. HLW accounts for over 95 percent of the total radioactivity produced in the process of nuclear electricity generation. HLW contains both long-lived and short-lived components, depending on the length of time it will take for the radioactivity of particular radionuclides to decrease to levels that are considered non-hazardous for people and the surrounding environment. If generally short-lived fission products can be separated from long-lived actinides, this distinction becomes important in management and disposal of HLW.
References:
Nuclear and Reactor Physics:
  1. J. R. Lamarsh, Introduction to Nuclear Reactor Theory, 2nd ed., Addison-Wesley, Reading, MA (1983).
  2. J. R. Lamarsh, A. J. Baratta, Introduction to Nuclear Engineering, 3d ed., Prentice-Hall, 2001, ISBN: 0-201-82498-1.
  3. W. M. Stacey, Nuclear Reactor Physics, John Wiley & Sons, 2001, ISBN: 0- 471-39127-1.
  4. Glasstone, Sesonske. Nuclear Reactor Engineering: Reactor Systems Engineering, Springer; 4th edition, 1994, ISBN: 978-0412985317
  5. W.S.C. Williams. Nuclear and Particle Physics. Clarendon Press; 1 edition, 1991, ISBN: 978-0198520467
  6. G.R.Keepin. Physics of Nuclear Kinetics. Addison-Wesley Pub. Co; 1st edition, 1965
  7. Robert Reed Burn, Introduction to Nuclear Reactor Operation, 1988.
  8. U.S. Department of Energy, Nuclear Physics and Reactor Theory. DOE Fundamentals Handbook, Volume 1 and 2. January 1993.

Advanced Reactor Physics:

  1. K. O. Ott, W. A. Bezella, Introductory Nuclear Reactor Statics, American Nuclear Society, Revised edition (1989), 1989, ISBN: 0-894-48033-2.
  2. K. O. Ott, R. J. Neuhold, Introductory Nuclear Reactor Dynamics, American Nuclear Society, 1985, ISBN: 0-894-48029-4.
  3. D. L. Hetrick, Dynamics of Nuclear Reactors, American Nuclear Society, 1993, ISBN: 0-894-48453-2. 
  4. E. E. Lewis, W. F. Miller, Computational Methods of Neutron Transport, American Nuclear Society, 1993, ISBN: 0-894-48452-4.

See above:

Radioactive Waste