2 - Nuclear Waste Categories

Abstract

This chapter deals with the different categories of nuclear waste like high-level waste and spent nuclear fuel, high-level Department of Energy (DOE) waste, transuranic waste, low-level waste, and mixed waste. High-level waste and spent nuclear fuel originate from different sources and require distinct handling, although the Nuclear Waste Policy Act of 1982 required that they be safely stored, transported, and finally disposed off in a mined geologic repository. High-level waste is the highly radioactive material resulting from the reprocessing of spent nuclear fuel or from defense production processes. This material includes liquid wastes, sludge, calcines, or other products remaining from the recovery of uranium and plutonium in a fuel reprocessing plant. Such waste contains fission products that result in the release of considerable decay energy. As a result, heavy shielding is required to control penetrating radiation and to dissipate decay heat. Spent nuclear fuel consists of irradiated fuel discharged from a nuclear reactor. This fuel may be reprocessed or may be considered as permanently discharged and eligible for repository disposal. Spent fuel may be generated from defense complex reactors, commercial nuclear power reactors or be classed as special fuels associated with government-sponsored research and demonstration programs, universities, and private industry. Transuranic (TRU) waste is defined as waste contaminated with alpha-emitting radionuclides with an atomic number greater than 92, half-lives greater than 20 years, and in concentrations greater than 100 nanocuries per gram of waste.