According to the United States Government Accountability Office (GAO), the structural integrity of Runite Dome in the Marshall Islands, described as a 115-meter-wide concrete ‘coffin’, is at risk. The dome was built over an unlined crater created by a nuclear explosion in 1958 and contains more than 120,000 tons of radioactive debris – much of which is made up of plutonium-239 contaminated soil. Rising sea levels and increasing hurricane intensity in the central Pacific have forced the 18-inch-thick concrete dome cap to compromise forces (for example, both rising and falling tides) that were not anticipated at the time of the dome’s construction and were never taken into account for its permanently stored design conditions. The porous nature of the coral substrate on which the crater sits allows radioactive waste to ‘float’ up and down with the tide and enables seawater to penetrate the debris. The continued seepage of seawater from the deteriorating concrete cover, with large cracks appearing on the surface, has created a ‘ticking time bomb’ environmental disaster that originated during the Cold War.
Runit Dome’s ticking time bomb: Cracks and a missing base allow radioactive water to flow
One dangerous aspect with the Runite Dome is not only that its exterior is broken, but there is also no under lining inside the dome. As reported by the GAO, the Defense Nuclear Agency (DNA), in collaboration with the US Army Corps of Engineers, used ‘Cactus’ blast craters to dispose of radioactive soil and did so without a concrete base to reduce costs when building the dome in the late 1970s. Therefore, radioactive waste is in constant contact with groundwater and rises and falls depending on ocean tides. This causes what is commonly referred to as ‘pumping’ or the daily release of radioactive isotopes into the lagoon surrounding Runite Dome.
How rising sea levels are breaking Runite Dome
Runit Island is only 25 feet above sea level, according to the U.S. Department of Energy’s 2024 climate report. Sea level rise is currently pushing radioactive groundwater up into the porous zone. This is causing greater internal pressure and ‘base’ cracking on the surface of the structure. The cracks are allowing rain to enter the structure, carrying plutonium-239 through existing channels in the ground and into the water table surrounding the structure. Reports indicate that a major storm could cause the internal contents of the Enewetuck Lagoon to overflow, as sediment and small particles would flow into the lagoon through channels.
Is the Runit Dome about to collapse?
Today, the collapse of Runite Dome is a scene of structural failure, and an example of decaying nuclear history. Reports from the Government Accountability Office (GAO) and the Department of Energy (DOE) have established that the ‘provisional’ 50-year design life has been reached. If no international action is taken to reinforce the unlined crater, the ever-rising Pacific tidal waters will continue to ‘pump’ plutonium into the environment. Protecting the Marshall Islands from catastrophic flooding is now a matter of global environmental justice or the need for urgent climate action.