New Fukushima Nuclear Power Plant Images Raise Safety Concerns - Popular Mechanics

New Fukushima Nuclear Power Plant Images Raise Safety Concerns

- On March 11, 2011, Japan’s Fukushima prefecture experienced a devastating earthquake and tsunami, which killed upwards of 20,000 people.
- One of the lasting legacies of the earthquake is the extensive damage to the Fukushima Daiichi Nuclear Power Plant that experienced meltdowns in three of its six nuclear reactors.
- Twelve years later, the clean up and decommission of the plant continues, and new evidence suggests that at least one reactor could be vulnerable to future earthquakes

On March 11, 2011, at 2:46 p.m. local time, Japan experienced a 9.1 magnitude earthquake—the biggest earthquake in the country’s recorded history—80 miles off the coast of Sendai. The shaking lasted six minutes, but the earthquake and the resulting 50-foot tsunami caused immense devastation and death, killing upwards of 20,000 people.

Twelve years later, Japan is still recovering from this historic earthquake, and nowhere can this be seen more plainly than at the Fukushima Daiichi Nuclear Power Plant. Although the plant, equipped with six nuclear reactors, terminated fission reactions automatically once it detected the earthquake, the resulting tsunami that arrived less an hour later breached the plant’s seawall and damaged the back-up generators needed to pump coolant to dissipate decay heat. This caused three of the six reactors to experience a meltdown over the next 72 hours.

Because of the immense radiation inside these reactors, engineers still don’t know the exact extent of the meltdowns. But for years, robotic rovers have investigated these highly irradiated zones to get a better understanding of each reactor’s status and—crucially—ability to withstand another earthquake.

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Earlier this week, the Associated Press reported that one of these robotic sojourns, conducted by an underwater remotely operated vehicle named ROV-A2, uncovered something troubling: exposed steel bars in the main support structure of Unit 1, along with missing pieces of its external concrete wall.

Located right under the nuclear core of Unit 1, this support structure wasn’t in jeopardy of failing on its own, but experts worried about its ability to withstand another earthquake if one were to strike. Because decommissioning and cleaning up Fukushima Daiichi will likely take decades to fully complete, the plant experiencing more earthquakes is likely. Just last year, the region was hit by another earthquake—thankfully the tremor was some 63 times less powerful than the devastating disaster in 2011.

Tokyo Electric Power Company Holdings (TEPCO), which operates Fukushima Daiichi, says that it will analyze the video taken by the underwater drone, along with other data, in the coming months to figure out ways to improve the unit’s earthquake resistance. This a priority, as 880 tons of melted nuclear fuel remains inside the three failed reactors—that’s about 10 times the fuel removed during the Three Mile Island clean up after the 1979 meltdown, according to the Associated Press.

Although nuclear disasters like Chernobyl, Three Mile Island, and Fukushima grab headlines, nuclear energy as a whole is actually a safer source of energy than its fossil fuel alternatives, eliminating mining deaths and helping to lower the number of people who die from pollution every year. The U.S. Department of Energy recognizes the need for nuclear to address climate change, and everything scientists and engineers can learn from this disaster will only make future nuclear reactors safer.

Darren lives in Portland, has a cat, and writes/edits about sci-fi and how our world works. You can find his previous stuff at Gizmodo and Paste if you look hard enough.