Fukushima nuclear power plant: how robots found the remains of nuclear fuel

Fukushima nuclear power plant: how robots found the remains of nuclear fuel
Fukushima nuclear power plant: how robots found the remains of nuclear fuel
10 February, 10:06TechnologyPhoto: itnan.ru
Experts working at the Japanese nuclear power plant "Fukushima" destroyed by the tsunami, 11 years after the accident, began to examine the inside of the reactor. It is still unknown how much molten radioactive fuel has accumulated there. The Japanese sent robots for reconnaissance.

Gennady Charodeyev

ABC News TV channel recalled that in 2011, the Fukushima nuclear power plant was severely damaged due to a 9-point earthquake and a powerful tsunami. As a result, people died, more than 150 thousand local residents had to be evacuated, and the damage amounted to billions of dollars. This is the second major accident in the world with serious consequences after Chernobyl.

The Japanese authorities still face the task of eliminating the consequences of the accident. But even well-trained and equipped specialists could not get inside the exploded reactors themselves without receiving a lethal dose of radiation. So, research work had to be entrusted to robots.

Разрушенная стихией АЭС "Фукусима" сегодня
Photo: techxplore.com

In February 2017, "smart" Japanese cars were able to crawl to the second block of the nuclear power plant, but the experiment had to be interrupted - the robot was blocked by fragments of the ruins.

Two other attempts also ended in nothing - one robot fell into a pit, the other had to be abandoned after a fruitless six-day search for fuel fragments. In total, the Japanese have recently lost a dozen reconnaissance robots, which, by the way, cost the treasury hundreds of millions of dollars.

Maybe still cover the reactor with a sarcophagus?

More than ten years have passed, but no one has been able to determine where the hundreds of tons of fuel from the three reactors are located, which were damaged due to the rampant elements. We only know that it overheated, turned into lava and melted the steel container. What happened next, no one knows. Did the fuel spill out of the reactors, or was something left inside? Did it gather in a single heap, spread out in a puddle, or splashed on the walls? However, without knowing the answers to these questions, it is impossible to draw up a plan to eliminate the nuclear power plant itself.

“It is difficult to create a robot that can work in unknown conditions,” said Hajime Asama , a professor at the University of Tokyo who was once approached by the Japanese government for help. - Until we sent the robot there, we do not know what conditions are there. And we cannot change them when the work is already in full swing inside.

Этот робот уже работает у первого реактора
Photo: Pinterest

According to the Rusbase publication, the Toshiba laboratory and its team of engineers and scientists, led by Kenji Matsuzaki , took up the matter. He had worked in Toshiba's nuclear division for more than 10 years, so he roughly understood the basic structure of a nuclear power plant.

It was planned that the robot would spend three days in the reactor, mapping it, following in the footsteps of the missing fuel. Matsuzaki himself monitored his work from the control center at a distance of 457 meters.

On the appointed day, at 4:30 AM, Toshiba technicians entered the reactor building, wearing full armor, and lowered the robot. The control was carried out using a special controller, and on the screens - complete darkness. The first day the robot studied the situation - he found out that the container was damaged more than expected. However, after eight hours of searching, traces of fuel could not be found, and the technicians pulled the robot out.

The next day, the car plunged back into the reactor. The allotted time until noon was coming to an end, and Matsuzaki began to get nervous. And then, blurry images resembling stalactites finally appeared on the screens. These were the first traces of fuel. The robot circled the area a little more, carefully documenting everything, and then it was lifted to the surface. When Matsuzaki announced that the mission had been successfully completed, the control center burst into applause.

Центр управления роботами
Photo: theepochtimes.com

However, the moment came when, due to previous failures with the use of robots at an emergency nuclear power plant, the Japanese government began to lean towards the option of building a sarcophagus around Fukushima in the manner of the one erected over Chernobyl .

With every million dollars spent, it becomes increasingly difficult for official Tokyo to explain to the people that robots are their hope.

Cars that are not afraid of radiation

According to the estimates of the operator of the Fukushima-1 NPP, the company TERSO , the final elimination of the consequences of the accident at the plant and the dismantling of the reactors will take at least 40-45 years and will require about 200 billion dollars.

Meanwhile, the leaks from the destroyed station are increasingly threatening the environment. Ecologists are not sounding the alarm in vain: scientists have found cesium from the Fukushima nuclear power plant in the waters of the Arctic Ocean.

In this regard, ABC News noted that Japanese engineers are in a hurry to justify the hopes of compatriots for "artificial intelligence." Operator TEPCO has begun surveying the interior of the first reactor with new robots. Everything was supposed to start on January 12 and involved studying the state of the inside of the reactor, where molten radioactive fuel accumulated during the 2011 accident. In particular, it was planned to send six robots with different functions to the reactor. However, before starting work, it turned out that one of the robots did not show the level of radiation. In addition, one of the six video cameras stopped recording the time. But work resumed in February.

At the first stage, it is supposed to take pictures of fragments of melted fuel.

A remote-controlled robot is already probing the worst-affected nuclear reactor in the first unit of the destroyed nuclear power plant and, according to the station operator, a guiding path has already been established for five subsequent robots. These "smart" machines will try to evaluate and take samples of molten fuel, which "emits deadly high radiation."

Робот-осьминог для работы на АЭС
Photo: ilenta.com

It is also expected that the work will last several days before full soundings of water, air and soil begin.

Earlier analyzes showed that the fuel in the first block was submerged in highly radioactive water to a depth of two meters. It also turned out that 900 tons of molten nuclear fuel remains inside the three reactors of the station, including about 280 tons at Unit 1. Experts consider its removal a very difficult task.

Tokyo Electric hopes to use a "robot arm" to remove the first scoop of molten fuel later this year from Unit 2, where internal robotic probes have made the most progress.

There are no looters in Fukushima

At the end of April, the Japanese government decided to allow the release into the ocean of water treated in the ALPS system, which cleans contaminated water from 62 radioactive elements, with the exception of tritium, from 2023. This decision caused concern in neighboring countries - inRussia , China, South Korea and the DPRK . The Japanese themselves are outraged by this initiative. At the same time, the IAEA announced its support for Tokyo's decision.

Journalists who occasionally visit Fukuksim, where more than 280,000 people lived before the accident, are struck by the fact that there are no people in the city. But from time to time, many Japanese come to look at their farm. None of them complains about their fate and everyone is glad that their houses have remained safe and sound all these 11 years - there are no marauders in the city!

“If the Chernobyl zone was mostly plundered, then in Fukushima everything remained almost untouched. A typical Japanese city, but without people. Many houses are perfectly preserved, the residents left them in a hurry, taking only the documents. People did not know that they would not return here. Traffic lights are still working in the ghost town, and street lighting is turned on in the evening. It looks creepy, ”say representatives of local authorities.

Some Fukushima residents, despite the police ban, returned home after a few days to rescue animals abandoned during the evacuation.

The New York Times spoke of Masami Yoshizawa , a Namie farmer who returned to his radiation-stricken ranch because he could not allow the authorities to enforce a government order to kill animals.

Десятки тысяч жителей Факусимы остались без крыши над головой
Photo: blic.rs

"These cows are living testament to human stupidity here at Fukushima," Masami said. “The government wants to kill them to erase what happened here and restore Japan to its pre-accident status quo. I won't let them do it."

This man regularly walks around looking for malnourished animals, which he sometimes has to pull by the ears to make them follow him home. In doing so, Masami tries to avoid police roadblocks, even though his stay in the city is illegal.

However, he was caught several times and forced to sign a prepared form apologizing for entering the forbidden territory. Masami signed, but first crossed out the clause with promises not to do so in the future.

As it turned out, not all Japanese rely on operators in the matter of radiation measurements. In Fukushima Prefecture, "for the sake of all the children of Japan", caring mothers united. On their own, they created a laboratory from scratch to test literally everything for radiation: rice, seafood, water, earth, moss, and even garbage from a vacuum cleaner. Interestingly, none of these women possessed the special knowledge for such activities, so they had to learn from scratch.

Laboratory worker Noriko Tanaka says the radiation problem is not limited to the contaminated area. In addition to possible health issues, there is a social factor - potential discrimination against growing children from contaminated territories. It's no secret that some teenagers evacuated from Fukushima to other prefectures face prejudice and bullying from their peers.

Жителям Фукусимы пока не разрешают вернуться домой
Photo: yaplakal.com

Entrepreneurial Japanese have figured out how to make money on the ghost towns that arose after the accident at the Fukushima nuclear power plant. For little money, tourists are taken to the abandoned city of Okuma, the closest to the nuclear power plant. The route then passes through Fukushima and a working farm and rice fields, where the effects of radiation on livestock and plants are being studied. The Japanese call their business "nuclear tourism".

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