The Runit Dome – or Cactus Crater Confinement Structure – is a dome-shaped structure on the Marshall Islandsin Enewetak Atoll, Oceania, built between 1977 and 1980. Sometimes picturesquely described as “tomb” or “sarcophagus“, this concrete structure with a diameter of 115 meters contains within it more than 80 thousand m3 of radioactive material produced during atomic tests carried out on the atoll between 1946 and 1958The island is currently uninhabited and over time has attracted much criticism, especially from local populations, for fear of possible environmental contamination.
History of Cactus Crater
Year 1947, Marshall Islands. At the time the entire archipelago was under the control of the USA and between the 1946 and the 1958 they were brought here 67 nuclear tests. Among these, one of the most famous was the Cactus testduring which a bomb was detonated 18 kilotons on Runit Island, Enewetak Atoll. Obviously before starting the tests, it was decided to temporarily relocate the 150 residents of the atoll in Ujelang, approximately 250 km awayThey will be able to return to their homes only in 1980after a complex restoration effort in the area by the US Government. All the islands were then inhabited again… all except one: theRunit Island.
Here in fact in the 1977 the presence of the crater was exploited to create a concrete containment structure within which more than 100 people were confined 80 thousand cubic meters Of soil and radioactive debris.
The construction of the Runit Dome
The Runit Dome is composed of several levels superimposed on each other, as also indicated by the image below.
At the top there is a level in concrete Often 45 centimeters which overhangs a further hollow concrete layer in the centerinside which there is contaminated waste. There is also a side wall to protect the sides of the structure but, as you can see, no lower confinement level. The base of Runit Dome is in fact the crater itself, which in turn contains contaminated material.
Possible risks associated with radioactivity
The idea of having a radioactive material storage a few kilometers from their home has worried local authorities over the years. Currently one of the most in-depth reports on the subject was made in 2020 by the US Department of Energy and right here it is said that at the moment the concrete structure it does not present any particular critical issues and is still able to guarantee the safety of the site – despite some cracks having been identified on its surface over time.
Nevertheless, attention remains high for a possible contamination of underground water, given the lack of a containment system at the base of the work: it is assumed that there may already be anomalous values and that they could even worsen in the coming years. Precisely for this reason, a program of radiochemical analysis of groundwater, so as to obtain a clearer overview and evaluate which interventions to carry out in the future.
