Low Level Waste is one of the several types of radioactive waste that are maintained at the INL. Upon examination, one finds that "Low Level" is a bit of a misnomer. This waste is not necessarily contaminated with low levels of contaminants, or with radionuclides that emit low levels of radiation. Instead, it's a "catch-all" category for all the radioactive waste that doesn't fit the definition of the radioactive waste categories of spent nuclear fuel, high-level waste, or transuranic waste.

Because it's a catch-all category, low-level waste is further categorized based on a combination of three different characteristics:

• Hazardous Chemicals: if the low-level waste also contains hazardous chemicals, it is called a "mixed" waste and must be managed to meet standards for both radioactive and hazardous waste.
• Transuranic Elements: if the low-level waste contains some transuranic elements, but not enough to qualify as transuranic waste, it still needs special handling to protect workers and the public from exposure. This waste is called "alpha-contaminated" low-level waste.
• Radiation Dose: if the potential dose to a person from the surface of a waste container is low enough to allow direct handling of the container, it is called "contact-handled" waste. If the potential dose is high enough to require greater protection of workers through distance and shielding, it is "remote-handled" waste."

Another issue that makes low level waste confusing is that these three characteristics can combine into different classes of low-level waste, with different risks and handling requirements. For example, low level waste needing the most special handling requirements would be remote-handled, alpha-contaminated, mixed waste. But you could also have contact-handled, non-alpha, mixed waste.

While some low level waste is as slightly radioactive as the name implies, some is highly radioactive in the short term. Other low level waste remains radioactive for a long time. While most low level waste can be disposed in shallow landfills meeting certain standards, the U.S. Nuclear Regulatory Commission requires that some "low level" waste be placed in a geologic repository, the same as spent nuclear fuel and high level waste.

In addition, there is contaminated soil at various locations around the INL that also qualifies as low level waste. Agencies are still assessing the volume of this contaminated soil as part of the Superfund cleanup process.

Decisions about management of low level waste at the INL are made after two factors are considered: what the waste is contaminated with, and where it came from.

• The contaminant and form of the waste determines how it can be treated, packaged, and disposed of. A liquid waste is treated differently than a solid, for example, and mixed wastes are treated differently than those that are not hazardous.
• Low level waste generated during routine, ongoing site operations must follow established DOE rules. However, if the low level waste is contaminated material being cleaned up as part of the Superfund process, DOE, EPA, and Idaho's DEQ must agree on how it will be managed. Superfund cleanup gives agencies some flexibility in how waste is managed, depending on risks it presents.

In recent years, the INL had treated some mixed and non-mixed low level waste at the Waste Receipt and Operations Center (WROC). This facility was able to resize and repackage waste for disposal. DOE also incinerated waste at the Waste Experimental Reduction Facility (WERF). Now, all legacy low level and mixed low level waste has been removed from the WROC, and the facility has been shut down. Some low level waste liquids are sent out of Idaho for treatment, with the residual material returned to the INL for disposal.

The INL no longer treats low level waste. Instead, the waste is allowed to accumulate at properly controlled low level waste staging locations until a sufficient inventory exists to support a shipment to a disposal location. The INL limits the amount of low-level waste in these accumulation areas to a total of 1000 cubic meters.

The Advanced Mixed Waste Treatment Project, constructed adjacent to the Radioactive Waste Management Complex, will be able to sort, size, repackage, and compact both mixed transuranic waste and mixed alpha-contaminated low level waste that contains smaller amounts of plutonium and americium. DOE is still determining how it will treat transuranic and mixed low level waste that contains PCBs and certain organic chemicals.

DOE disposes of some non-mixed, non-alpha contaminated, low level waste from ongoing operations across the INL at the Subsurface Disposal Area of the Radioactive Waste Management Complex (RWMC). Waste that can be handled by direct contact is placed in a landfill called the Active Pit . Remote-handled waste is disposed of in concrete vaults.

INL will continue to dispose of some INL-generated low level waste while the Subsurface Disposal Area at the RWMC remains open. The RWMC is currently scheduled to close in 2006, with one exception: some remote-handled LLW generated by the Naval Nuclear Propulsion Program's operations at the INL can be disposed of at the RWMC through 2008. When it closes the RWMC, DOE will design a cover for the landfill to prevent water, animals, or humans from getting into the pit.

DOE recently issued a Record of Decision concerning low level (LLW) and mixed low-level waste (MLLW) treatment and disposal. The decision set up "regional" disposal sites for wastes generated as part of ongoing DOE operations across the country. DOE designated the Hanford, Washington, and the Nevada Test Site as mixed low level and non-mixed low level waste disposal facilities for all of the facilities in the DOE complex. To prepare for closure of the Subsurface Disposal Area, DOE has been sending some INL mixed low level waste and non-mixed low level waste to these sites. DOE will also continue to use commercial treatment and disposal facilities.

The Site Treatment Plan gives the Idaho Department of Environmental Quality approval authority over incoming mixed low level waste. DEQ typically requires that waste approved for shipment to INL treatment facilities be treated and removed from the INL within one year. The INL no longer receives low level waste from offsite for disposal at the INL.

• Placed in the INL CERCLA Disposal Facility: the new landfill near INTEC constructed for contaminated soils and debris.
• Left in place.
• Treated or capped in place to reduce risks to an acceptable level.
• Dug up, treated and shipped off-site for disposal.

Much of the buried waste at the INL is low level waste, so low level waste is sometimes confused with "buried waste." The term "buried waste," however, usually refers to plutonium-contaminated waste that was buried in some of the landfill's pits and trenches before 1970. Most of this waste came from the weapons production facility at Rocky Flats, Colorado. Cleanup of this "buried waste" remains a top priority.