The Waste Isolation Pilot Plant (WIPP) in southeast New Mexico is the nation’s first and only operating deep geologic repository for radioactive wastes.
Since 1999, the U.S. Department of Energy (DOE) site hosts disposal canisters filled with transuranic (TRU) radioactive waste—rags, tools, clothing, soils and other debris contaminated with man-made radioactive elements—from nuclear weapons production facilities and cleanup sites. The waste is kept 2,150 feet below ground in the Salado Formation, a giant salt deposit that stretches from northern Mexico through southeastern New Mexico and into west Texas. Salt beds keep the waste dry and seal it away from groundwater that could eventually move the waste to the surface.
According to the DOE, over 171,000 containers or almost 12,000 cubic meters of waste have been emplaced underground at WIPP. This waste came from nearly 12,000 shipments, which safely traveled more than 14 million loaded miles. Historically, the largest contributors of waste to WIPP have been the Idaho National Laboratory, the Rocky Flats site in Colorado, the Savannah River Site in South Carolina, the Hanford site in Washington, and the Los Alamos National Laboratory in New Mexico.
The U.S. Environmental Protection Agency’s Radiation Protection Program and the New Mexico Department of Environment are primarily responsible for regulating WIPP. Through New Mexico’s Radioactive Waste Consultation Task Force, six state agencies additionally work together on the safe transportation of waste to the facility.
Accident and Recovery
In February 2014, two isolated events happened at WIPP – a salt haul truck fire and a radiological release. First, on Feb. 5, 2014, a salt haul truck caught fire underground and was subsequently extinguished. This event caused the temporary evacuation and closure of the underground disposal area. Six workers were treated for smoke inhalation, but no serious injuries resulted from the fire.
On Feb. 14, 2014, a monitor device detected radiation in the air at the above-ground portion of the site. Federal inspectors determined various lapses in safety procedures led to chemically incompatible materials being packed together in waste drums sent to the disposal site. The 13 employees present during the release event were tested for exposure. Initially, tests indicated some radioactivity above normal background levels, but follow-up samples found no detectable amounts of radioactivity. Subsequently, 22 workers tested positive for exposure to radiation, although not at levels that would cause health concerns, according to DOE. The site ceased operations in February 2014 to investigate the leak and review safety protocols.
DOE has taken steps to resume safe operations at WIPP including the completion of a documented safety analysis, cold operations, and a management self-assessment. The documented safety analysis, implemented in May 2016, included approximately 120 new or revised safety procedures. The subsequent cold operations allowed for WIPP crews to test these new procedures with empty containers. The site has also taken actions to stabilize portions of the repository and to increase ventilation
In December 2016, the State of New Mexico gave approval to resume operations at the facility once DOE completes its checklist of corrective actions. There are nearly 20 identified issues to be resolved before shipments may resume. DOE hopes to resume shipments by April or May 2017. DOE agreed to pay New Mexico $73 million as compensation for violations of safety procedures at the plant.
The safe and timely resumption of WIPP operations impacts cleanup activities across the country at sites generating and processing TRU waste. These sites are waiting and facing concerns over storage capacity and the ability to meet cleanup milestones. WIPP is conducting planning meetings with state regional groups and tribal representatives to ensure preparedness prior to the resumption of shipments. Preparedness activities include: pre-shipment communications, public outreach for active transportation corridors, and “dry runs” for each corridor to test notification, monitoring, and inspection.
Congress authorized the WIPP facility in 1979, after the underground salt deposits outside Carlsbad, N.M. were found to be an appropriate storage site for radioactive waste. DOE’s National Security and Military Applications of Nuclear Energy Authorization Act of 1980, enacted in December 1979, approved funding to construct the site, but only allowed for storage of defense-generated waste.
In 1981, New Mexico sued the federal government to halt construction of the site. The lawsuit’s settlement gave New Mexico the right to conduct independent testing and monitoring of the site, and established a Consent and Cooperation agreement between the State and DOE. The agreement was subsequently amended requiring the site to comply with state environmental laws.
In 1992, Congress passed the WIPP Land Withdrawal Act, permitting waste to be moved to the site. The Act also requires WIPP to comply with federal Resource Conservation and Recovery Act (RCRA), the Solid Waste Disposal Act, and to be certified by the U.S. Environmental Protection Agency. The law prohibited WIPP from accepting any used nuclear fuel or other high-level radioactive waste, even for testing purposes.
Following further testing and certifications in the 1990s, WIPP officially began accepting TRU waste shipments in March 1999.
Types of Wastes Stored at WIPP
TRU waste is radioactive material that is heavier than uranium, has a half-life greater than 20 years, and activity greater than 100 nanocuries of per gram of waste. Plutonium isotopes and other elements that are listed higher than uranium on the periodic table are consider transuranic and contaminate TRU waste. There are two types of TRU wastes stored at WIPP: contact-handled waste, which emits relatively little radiation and can be handled by workers; and remote-handled waste, which emits greater levels of radiation and requires heavier shielding and remote-handling equipment. According to law, remote-handled TRU waste will only account for about percent of all waste stored at WIPP.
In July 2016, DOE developed and issued a new WIPP waste acceptance criteria, which must be followed by the TRU waste programs at other sites. These actions aim to promote safety and clarify roles and responsibilities among the agency headquarters program, field operations and contractors.
By the Numbers:
- 2,150: Depth, in feet, of WIPP’s underground storage facility
- 90,000: Amount, in cubic meters, of contact-handled TRU waste stored at WIPP
- 350: Amount, in cubic meters, of remote-handled TRU waste stored at WIPP
- Over 11,894: Shipments to WIPP since its inception in 1999
- 22: Number of Department of Energy legacy TRU waste sites cleaned up