Decades old "nuclear coffin" on Pacific Island cracks under climate stress

Runit Island, hosting the "Runit Dome", is often referred to as the "nuclear coffin" or simply, "nuclear grave". The island is part of the Enewetak Atoll in the Marshall Islands located in the Pacific.

Renowned for its high radioactivity, it exceeds even that of Chernobyl. The US has stored the remnants from dropping 67 atomic bombs on the Bikini and Enewetak Atolls here, between 1946 and 1958.

Hidden beneath a layer of concrete is radioactive waste and contaminated soil among other things, which include harmful plutonium. The waste originated from six different islands in the late 1970s, including Nevada (approximately 62 miles from Las Vegas), where over 900 nuclear tests were conducted. The dome has a diameter of 377 feet and a thickness of about 1.5 feet.

The "nuclear coffin" was envisioned as a temporary solution, but it has not been replaced with a permanent one for many decades.

The passage of time has not been kind to the structure. According to IFL Science, 2020 studies highlighted that the dome now has a web of cracks worsening due to the Pacific's rising temperatures.

The rising sea level also plays a part by allowing more water to reach the "Runit Dome" and erode its structure.

Continued deterioration could potentially cause the radioactive material to leak into the surrounding soil and waters. Ken Buesseler, a renowned expert on marine radioactivity from the Woods Hole Oceanographic Institution, was quoted by IFL Science in 2020:

As long as the plutonium remains under the dome, it won't be a significant new source of radiation to the Pacific Ocean.

Buesseler underscored that future developments greatly rely on increased sea levels and the frequency of storms and tides: "Currently, it's only a small source of radiation. However, we need to frequently monitor it to understand what's happening and communicate that information directly to affected regional communities."

Two scientists from Columbia University backed this viewpoint in a 2022 article in Scientific American. They suggested that the U.S. Congress should fund such independent research and develop a suitable emergency plan.