Page 2: France's Nuclear Testing Programme
Landslides, tsunamis and earthquakes caused by testing
From 1975, all nuclear blasts were carried out underground, causing both short-term and long-term environmental damage. At the time of the explosion, fracturing of the atoll surface triggered landslides, tsunamis and earthquakes. A report by the IPPNW and the Institute for Energy and Environmental Research on the Environmental Effects of French Nuclear Testing found evidence that radionuclides were vented into the environment. Possible long-term effects include leakage of fission products to the biosphere and transfer of dissolved plutonium from the lagoon to the ocean and the food chain. A number of scientific missions to Moruroa described severe impairment to the atoll. The damage included fissures in the limestone which are propagated by the testing, and surface subsidences of large areas of the atoll.
At least one major test-related landslide and consequent tsunami occurred in Moruroa on 25 July 1979. The report on the Environmental Effects of Nuclear Testing claims that a 120 kiloton weapon that was being tested, became stuck inside the shaft and could not be dislodged but was exploded anyway. The explosion resulted in a major underwater landslide of at least one million cubic metres of coral and rock and created a vast cavity. The underwater landslide produced a major tidal wave comparable to a tsunami, which spread through the Tuamotu Archipelago and injured people on the southern part of Moruroa.
Radionuclides detected in marine organisms
A mission in 1983 to Moruroa comprising scientists from Australia, New Zealand and Papua New Guinea identified unusual concentrations of iodine-131 (I-131) in marine organisms. Krypton-85 and tritium (see Chart 1) were also discovered in the air and water, indicating that venting had occurred. In 1987, a mission to the region by the scientist and researcher, Jacques Cousteau, found raised levels of I-131 in all sediment samples and plankton. Since I-131 has a short half life of 8.05 days, its presence could only be attributed to a recent emission.
The Australian, New Zealand and Papua New Guinea Mission to Moruroa in 1983 discovered that plutonium-239 concentrations in the air were about four times greater than in continental France.
Pristine marine environment used as nuclear dumping ground
The underground tests conducted at Moruroa turned it into a long-term waste dump, according to the IPPNW. Nuclear wastes existed under the atoll, without any of the ordinary safeguards that apply to a nuclear waste repository. The land area was also used to store radioactive waste (including metal scrap, wood, plastic bags and clothing) on the north coast of the atoll, which covers 30,000 square metres. In addition, a bomb broke apart on the surface of Moruroa on 21 July 1966, dispersing plutonium-239, which was confined to the area by fixing it in place with a layer of bitumen. Cyclones hit Moruroa in 1981, washing radioactive waste from the coral rim into the lagoon, including the plutonium-based bitumen.
The report on the Environmental Effects of French Nuclear Testing maintains that such waste management practices have resulted in the sediment of the lagoon containing an estimated 20 kilograms of plutonium (see Chart 1). The Australian, New Zealand and Papua New Guinea Mission to Moruroa in 1983 discovered that Plutonium-239 concentrations in the air were about four times greater than in continental France. About 75 percent of the caesium and strontium that were dispersed remained underground for many years and some may have found its way into the lagoons and ocean.
Moruroa was also used as a safety trial area. Safety trials aim at checking whether an atomic bomb will explode on impact with a hard surface. In the case of a "safe" bomb, or a "successful" safety trial, the impact does not cause a nuclear detonation but breaks apart the bomb, scattering plutonium-239 about the site.