Tokyo Electric Power Company (TEPCO), the primary operator of the Fukushima Daiichi Nuclear Power Plant, has been sending robotic probes into the nuclear plant since last year to study the structural integrity of Fukushima.
The footage the company examined showed that the nuclear cores had melted through the containment chambers in the reactor and that the multiple explosions the facility experienced had caused severe structural damage to the reactor’s support system.
Scientists are currently reviewing the footage to determine if the site can survive a secondary earthquake and what measures they will need to take to ensure the safety of the reactors and containment of the radioactive material.
With around 880 tonnes of radioactive material remaining in the three reactors, TEPCO and IAEA officials are working to determine the best course of action in the event of another natural disaster.
The Fall Of The Fukushima Nuclear Power Plant
On the 11th of March 2011, an earthquake on the coast of Hawaii had ripple effects that were cast over the Pacific Ocean, decimating the Fukushima Nuclear Power Plant in Japan.
The Tōhoku Earthquake, which registered a 9,1 magnitude on the Richter scale, is one of the deadliest ever recorded in Japan and resulted in the most destructive nuclear disaster the world had seen since the Chernobyl disaster of 1986.
Upon detection of the earthquake, the nuclear reactors at the power plant were shut down automatically by the plant’s security system. In turn, this shut down the electrical systems at the plant and switched power over to the emergency diesel generators to continue to supply power to the pumps that circulated water through the reactor.
Shortly after the effects of the earthquake were felt, a tsunami with waves measuring over 46 ft (14 m) followed. The power plant’s seawall was not high enough to stop the waves, leading to water flowing over the wall and flooding the lower section of the facility.
The water submerged the emergency generators, cutting off power to the entire facility. With no way to pump water through the cores, three reactors experienced nuclear meltdowns, which caused multiple hydrogen explosions around the facility.
In the aftermath of the disaster, large amounts of radiation were released into the atmosphere and the Pacific Ocean, leading to the evacuation of over 150 000 people who lived in the surrounding areas.
The State Of Fukushima 12 Years Later
Using an underwater remotely operated vehicle, named ROV-A2, Scientists investigated the structural integrity of reactor room 1, which was the most heavily damaged during the meltdown.
The footage showed that although majority of the radioactive material is contained within the reactor’s chamber, the concrete pedestal that holds the reactor was severely damaged, additionally, the steel support beams within have been exposed to the elements for the past 12 years.
Although researchers aren’t concerned that the structure would merely collapse on its own, they are worried that another earthquake could damage the supports more and possibly cause the reactor chamber to collapse.
TEPCO officials have stated that the images taken at reactor site one show molten nuclear fuel at the bottom of the reactor’s chamber, which probably fell during the meltdown.
The molten substance measured about 20 in (50 cm) and was less extensive than what was seen in the other two reactor sites, showing that all three meltdowns had progressed differently.
TEPCO plans to use 3D modeling to map the facility, so they can start work on adding additional support features to the degrading structure to increase its earthquake resistance.