15 Waste Isolation Pilot Plant

LOCATION Delaware Basin, New Mexico, USA

NEAREST POPULATION HUB Carlsbad, New Mexico

SECRECY OVERVIEW Access restricted: a deep repository for America’s nuclear waste.

The Waste Isolation Pilot Plant (WIPP), located in Eddy County, New Mexico, has served as a rubbish dump for much of the US’s transuranic radioactive waste since 1999. Chosen for its stable tectonics and geological characteristics, it is expected to receive some 38,000 shipments of waste over 35 years. However, the site will remain off-limits to future generations for perhaps 10,000 years.

Transuranic waste consists mostly of clothing, tools, fabrics, soil and assorted other materials that have been contaminated with radioactive elements with atomic numbers greater than that of uranium (principally plutonium). This is the most dangerous waste produced as a by-product of the various US nuclear research programs, and its disposal presents a significant challenge.

After a prospective location in Kansas for the storage of such waste was rejected, the site in New Mexico gained support. The Delaware Basin, a salt basin created in the Permian period of geological time (some 250 million years ago) by a shallow sea undergoing a series of evaporation cycles, was chosen because of its geological suitability and the absence of potentially dangerous groundwater. Congress authorized construction of the WIPP in 1979 and testing at the facility began in 1988. In March 1999, the first waste shipment arrived from the Los Alamos nuclear weapons research and development facility in Albuquerque.

UNDER CONSTRUCTION One of WIPP’s underground tunnels, buried at a depth of some 650 meters (2,130 ft) in the middle of the thick salt bed. The first exploratory shaft at the New Mexico site was sunk in 1981, a full 18 years before WIPP received its first shipment of waste.

Transuranic waste is given one of two major classifications: it is either “Contact-handled” (CH), which means it can be handled by workers in controlled conditions without any extra shielding beyond the container it comes in; or it is “remote-handled” (RH), which means it emits greater amounts of radiation and must be transported and handled using lead-lined containers. RH waste accounts for only about 4 percent of the total brought to the facility.

Disposal rooms for the waste material are located about 600 meters (2,000 ft) beneath the Basin’s surface (which is to say, about one and a half times deeper than the Empire State Building is high). RH waste canisters are stored in boreholes drilled into the walls of the store rooms, which are then capped with concrete. CH waste, meanwhile, is simply layered on the floors. Once the repository is full, it will eventually collapse in on itself and any gaps will be filled with salt until the WIPP is entirely encased, hundreds of meters below ground.

The WIPP is regulated by a variety of agencies, of which the most important are the Federal Department of Energy and the New Mexico Environment Department. Access to the plant is necessarily tightly controlled, and the site is surrounded by a large fence.

Anyone visiting on official business must watch a safety film before entering and wear appropriate equipment (including emergency breathing apparatus and a radiation monitor, if going underground). All waste shipments are tracked by satellite from a central control center, and all routes to the WIPP have stringent safety and security regimes, as well as some 25,000 trained responders in the event of an emergency.

While keeping people away from the site today is the immediate concern, it is equally important to ensure that future generations do not stumble upon it. For this reason, a think-tank of scientists, anthropologists and linguists has spent years developing a system to warn the people of the far future to keep away. The resultant plan employs “Passive Institutional Controls,” a series of verbal and non-verbal markers designed to indicate that the area is not safe.

So what does this mean in practice? Firstly, once the plant has been filled in, a sloped earthen hill (called a berm) will surround the facility’s 50-hectare (120-acre) footprint, with a height of 11 meters (36 ft) and width of 33 meters (110 ft). Within the soil will be 128 equally spaced metal objects visible to radar, as well as magnets to give the area its own magnetic signature. Granite monuments, 8 meters (27 ft) high, will mark the perimeter of the berm, with another layer marking the outer edges of a control area covering some 10 square kilometers (4 sq miles).

In addition, an information center will be built in the middle of the facility’s footprint, constructed from granite and inscribed with messages in several languages as well as pictograms. Two further rooms containing the same information will be buried elsewhere on the site, and records will also be sent to archives throughout the world in order that maps, reference works and the like can be accurately maintained. Finally, 23-centimeter (9-in) discs made of granite, fired clay or aluminum oxide will be randomly buried across the site, each carrying a warning in one of seven languages (English, Arabic, Chinese, French, Russian, Spanish and Navajo). Rarely can a place that wants to keep people out have had so many indicators of its precise location.

BURIED FOR ALL TIME This schematic gives an overview of the WIPP site. The waste disposal area is contained within a sedimentary layer known as the Salado Formation, which consists of salt, clay and shale. The salt will eventually isolate the radioactive waste from the outside world.