In reality, we already know how to store nuclear waste long-term and in fact are already storing military nuclear waste at a site 26 miles southeast of Carlsbad, New Mexico, called WIPP. What is different about WIPP from Yucca Mountain that makes it a desirable repository? The WIPP site is located in the Chihuahuan Desert, the largest desert in North America, but 250 million years ago the area was a shallow inland sea known as the Permian Sea. Over millions of years the sea subsided and the water evaporated, leaving a 2,000-foot thick bed of salt known as the Salado Formation. The salt bed lies on an impermeable rock layer and is covered by an impermeable layer of rock called caliche that prevents water from entering from the surface (8).

There are a number of advantages of a salt bed formation for permanently iso­lating radioactive waste. In contrast to the complex geology of Yucca Mountain, a rock salt formation is much simpler. It is geologically stable and not subject to fracturing from earthquakes; flowing water has not been present for 250 million years or the salt would have dissolved away; and rock salt is a crystalline rock with plasticity that slowly moves to fill in voids (25). Some concerns have been raised about the presence of karst, a type of topography in which there are sinkholes and large voids such as caves that could lead to flowing water at the site. However, a detailed review of scientific publications and reports does not support the pres­ence of karst at WIPP (26). The EPA has also evaluated this possibility and has concluded that the WIPP site does not show any evidence of karst (27).

The history of WIPP begins in the era of World War II when the national laboratory at Los Alamos, New Mexico, was developing nuclear weapons. A number of other national laboratories and sites were developed under the auspices of the now-extinct Atomic Energy Commission, which morphed into the current Department of Energy (DOE). These include the Idaho National Environmental and Engineering Laboratory (INEEL), Rocky Flats Environmental Technology Site (Colorado), Savannah River Site (South Carolina), Hanford Site (Washington), Argonne National Laboratory (Illinois), Nevada Test Site, and Lawrence Livermore National Laboratory (California). All of these sites were, and some still are, involved in various ways with research on uranium and plutonium and the development or maintenance of nuclear weapons.

An unavoidable result of working with uranium and plutonium is that trans­uranic (TRU) waste is produced. Recall that transuranics are radioisotopes that have a higher atomic mass than uranium. TRU waste consists of contaminated clothing, plastics, soil, sludge, tools, and other items that are used in producing or working with TRU. Most of the TRU waste is plutonium but can also include americium, neptunium, and other transuranics. As the volume of waste built up at these sites, the National Academy of Sciences concluded in 1957 that an underground repository in salt beds would be the best method of disposal. Until that could be done, however, the TRU waste generated at Los Alamos National Laboratory was stored in thousands of barrels under plastic tents out in the open. In 2000 a severe forest fire came within 500 yards of the barrels (8). If these bar­rels had burned and the radionuclides had been airborne in the fire, it would have been a major environmental disaster. Clearly, on-site storage under poorly designed conditions was not a good way to deal with TRU waste!

Congress authorized WIPP in 1979 as a research and development storage site for radioactive TRU waste from defense activities that are not regulated by the Nuclear Regulatory Commission (NRC). The DOE was given the responsibility for research and development of the site, and the EPA was to establish the radioac­tive waste disposal regulations for the site. Lawsuits were subsequently brought by the state of New Mexico and by various environmental groups to stop WIPP, but in 1999 these lawsuits were resolved and the site began receiving TRU waste. By 2005 a total of12 federal sites were delivering their TRU waste to WIPP, including the last of the shipments from Rocky Flats in Colorado where plutonium triggers were produced, allowing this hazardous site to close a year ahead of schedule (28).

WIPP was designated by the WIPP Land Withdrawal Act of 1992 to store only low level TRU waste that could be contact-handled, meaning that the storage con­tainers shield the waste sufficiently so that it can be handled by workers without further shielding. But there was also a need to store waste with higher levels of radioactivity, known as remote-handled TRU waste, at WIPP. This waste requires further lead shielding and special remote handling. The EPA approved a DOE plan for storage of remote-handled TRU in 2004 and the state of New Mexico gave its approval in 2006, allowing the first shipment of this type of waste (28). Current law allows for 96% of the TRU waste stored at WIPP to be contact-handled and up to 4% to be remote-handled (29). The law requires that WIPP be recertified by the EPA every five years, and it received its second recertification in 2010, indicating that WIPP complies with federal disposal regulations to safely contain TRU waste for the regulatory period of 10,000 years (30).

Low level contact-handled TRU waste is transported from around the country in special containers carried by flat-bed trucks that are monitored by satellite. Seven 55-gallon barrels fit into a specially designed cylindrical cask 8 feet in diam­eter by 10 feet tall called a TRUPACT-II. These casks have been approved by the NRC after tests show that they can survive severe crashes and punctures followed by fires or immersion in water. More than 10,000 shipments of this waste have been sent safely to WIPP from sites all over the United States by the end of 2011 (31). In reality the public is in much greater danger from the enormous volume of highly toxic chemicals that routinely travel through our cities on trucks and trains than from the shipments of TRU waste. The remote-handled TRU waste requires a different kind of container since it is more radioactive. The NRC has certified two different containers for shipping remote-handled TRU, which have more rig­orous requirements and are heavily shielded with steel and lead. Once the trucks arrive at WIPP with the waste, the casks are opened and the drums of waste are removed and stored in the WIPP site (32).

The WIPP site has four shafts sunk 2,150 feet into the Salado formation. At the base of the shafts there will eventually be eight panels divided into seven cham­bers 33 feet wide by 13 feet high. Thousands of barrels of contact-handled TRU are stored in columns in the chambers, while the remote-handled TRU waste is stored in shielded casks in boreholes carved into the chamber walls. Two of the panels have already been filled and sealed off to let the slow but inevitable creep of the salt enfold the barrels and compact them to about a third of their present size (8). Thus immobilized, the TRU waste will be safely isolated for millions of years, but after 250,000 years (ten half-lives of 239Pu), a blink in the lifetime of a salt mine, it will no longer be dangerous.

Why is there so much controversy and study of Yucca Mountain if there is already an approved repository for radioactive waste? Why not just store the spent nuclear fuel at WIPP? There are several factors to consider in answering these questions. The first factor gets back to politics. The laws that authorized WIPP specifically allowed only TRU waste from defense-related installations to be stored there, and separate legislation mandated that only Yucca Mountain be studied for spent nuclear fuel waste from commercial reactors. So the current law does not allow WIPP to be used for disposal of spent nuclear fuel. Of course, in principle, the law could be changed, so the question is whether WIPP could handle the waste from nuclear reactors. According to D. Richard Anderson (“Rip”), the scientist who was in charge of the risk assessment analysis for WIPP, “WIPP could safely hold all the nuclear waste in the world. Six million cubic feet—585,000 thousand barrels—is the limit by regulation here. In practice, the mine, or another mine next door, could take millions” (8). So we really do have a solution to long-term storage of radioactive waste.

But there is one more factor to consider and that is whether it is desirable to permanently store the waste from spent nuclear fuel. The Yucca Mountain site is specifically designed so that stored waste could be removed if desired before permanently sealing the disposal site. But the plasticity of the rock salt ensures that the waste stored there can never be retrieved. At this point, you are probably thinking that I have gone off the deep end. Isn’t permanent storage the Holy Grail of nuclear waste management?