Radioactive wastes are materials “left over” from the numerous nuclear processes, natural or human made. As the name states, all are radioactive to varying degrees and intensities. All have negative health and environmental consequences, both from their radioactivity and their chemical toxicity, requiring them to be sequestered from the environment in a permanent and responsible manner, in some cases for tens- to hundreds of thousands of years.

While there are several official categories of radioactive waste, in the U.S. the two most important that relate to nuclear power are “high-level” (HLRW) and “low-level” (LLRW) radioactive waste:

“High-Level” Radioactive Waste

Most of the time this category will pertain to the so-called “spent” reactor fuel, no longer usable to efficiently produce heat energy in a nuclear reactor, but still highly radioactive. Fresh new reactor fuel going into a reactor is almost entirely uranium. After 1-1/2 to 2 years of “fissioning” uranium atoms to produce heat, the fuel is no longer efficient enough to remain in the reactor, and must be replaced. In some cases because of the intense fissioning that has taken place over the useful life of reactor fuel, the “spent” fuel can be up to a million times more radioactive coming out of a reactor than when it went in.

In addition the process of fissioning uranium atoms (splitting them apart to release heat to boil water to create steam) creates smaller atoms of a multitude of types called “fission products,” which are extremely radioactive, and relatively shorter lived. Also, sometimes the uranium atoms, instead of splitting apart, capture neutrons created during fission and become larger atoms called “transuranics.” These are also very radioactive, and last for hundreds to thousands of years. Finally, up to 95% of the uranium remains un-fissioned in the “spent” fuel. Together, these are the components found in spent fuel, which are now considered “high-level” radioactive waste. Because of the long life of the transuranics, this hazardous waste must be keep out of the environment for hundreds of thousands of years. 

“Low-Level” Radioactive Waste

In the U.S. the many forms of radioactive wastes from the nuclear reactors that are not spent reactor fuel end up classified as “low-level” radioactive wastes (See LLRW fact sheet). (Lisa, I don’t know what fact sheet this is. Waiting to hear back from Dave.) These wastes do have to be below a certain level of radioactivity for a given volume of waste, but can consist of some items and materials that are intensely radioactive and hazardous. Some examples are filters and resins from nuclear reactor filtration systems on the high end of hazard, to contaminated tools and clothing on the lower end. Much of the construction rubble from the actual nuclear reactor decommissioning (See Decommissioning) is classified as LLRW.

All LLRW must be disposed of in an appropriate, licensed disposal facility. The U.S. historically had six such sites, all of which are currently closed and leaking. New sites have been established in Utah and Texas. The nuclear industry is seeking to open others.

Other Forms of Radioactive Wastes:

While the HLRW is of greatest concern and hazard, other forms of radioactive waste from the Nuclear Age exist which are also hazardous:

Uranium Mill Tailings: To get reactor fuel in the first place, you have to mine and then process the uranium. Uranium mining has taken place worldwide in the U.S., Canada, Australia, Niger, Czech Republic and elsewhere. Most comes from Indigenous people’s lands. Over 200 million tons of uranium mining leftovers called tailings exist, awaiting treatment and cleanup. In the U.S., over 10,000 abandoned or unremediated uranium mining sites exist, mostly in the Southwest on Indigenous lands.

NARM and NORM: NARM stands for “nuclear accelerator radioactive materials,” and are radioactive isotopes that are created during nuclear experiments. NORM are “naturally occurring radioactive materials” which are unearthed or collected through natural processes. Both classes are radioactive, and present health and safety issues to people and the environment.

Depleted Uranium: Uranium comes in many forms, with varying levels, intensities and types of radioactivity. Uranium ore contains many of these types, but only one – U-235 – is useful for producing electricity in commercial nuclear power plants. Because it is not as abundant as its brother and sister types, extracting this useful type of uranium from ore leaves huge quantities of less-useful types of uranium, particularly U-238, which is “depleted” of the removed U-235. This U-238, while still uranium, is not as radioactive as U-235; and so its commercial uses are more limited. It is however still uranium; and because of its density, it has been manufactured into anti-tank munitions and bombs. Large quantities of it remain, which has to be disposed of as radioactive waste.