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‘Scorpion‘ robot mission inside Fukushima reactor aborted

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December 8, 2019

A “scorpion” robot sent into a Japanese nuclear reactor to learn about the damage suffered in a tsunami-induced meltdown had its mission aborted after the probe ran into trouble, Tokyo Electric Power company said Thursday.

TEPCO, the operator of the Fukushima nuclear plant, sent the remote-controlled device into the No. 2 reactor where radiation levels have recently hit record highs.

The “scorpion” robot, so-called because it can lift up its camera-mounted tail to achieve better viewing angles, is also designed to crawl over rubble inside the damaged facility.

But it could not reach its target destination beneath a pressure vessel through which nuclear fuel is believed to have melted because the robot had difficulty moving, a company spokeswoman said.

“It‘s not immediately clear if that‘s because of radiation or obstacles,” she said, adding that TEPCO is checking what data the robot was able to obtain, including images.

A massive undersea earthquake on March 11, 2011 sent a huge tsunami barrelling into Japan‘s northeast coast, leaving more than 18,000 people dead or missing, and sending three reactors into meltdown at the plant in the worst such accident since Chernobyl in 1986.

The Japanese government said in December that it expects the total costs — including compensation, decommissioning and decontamination — to reach 21.5 trillion yen ($189 billion) in a process likely to take decades as high radiation levels slow operations.

The robot, 60 centimetres (24 inches) long, is made by Toshiba and equipped with two cameras and sensors to gauge radiation levels and temperatures.

“Scorpion‘s mission is to take images of the situation and collect data inside the containment vessel,” TEPCO spokesman Shinichi Nakakuki said earlier.

“Challenges include enduring high levels of radiation and moving on the rough surface,” he said.

Radiation levels inside the reactor were estimated last week at 650 sieverts per hour at one spot, which can effectively shut down robots in hours.

But the probe — designed to withstand up to 1,000 sieverts of radiation in total — would not sustain severe damage because it was unlikely to remain for too long at a single point, Nakakuki said.

https://livingstonledger.com/scorpion-robot-mission-inside-fukushima-reactor-aborted/

December 8, 2019 Posted by | fukushima 2019 | , , | Leave a comment

Robot pulled from Fukushima reactor due to radiation

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December 6, 2019

Cleaner robot pulled from Fukushima reactor as record radiation levels damage its camera

A remote-controlled cleaning robot sent into a damaged reactor at Japan‘s Fukushima nuclear plant had to be removed before it completed its work because of camera problems most likely caused by high radiation levels.

It was the first time a robot has entered the chamber inside the Unit 2 reactor since a March 2011 earthquake and tsunami critically damaged the Fukushima Da-ichi nuclear plant.

Tokyo Electric Power Co. said it was trying to inspect and clean a passage before another robot does a fuller examination to assess damage to the structure and its fuel. 

WHAT HAPPENED? 

The robot went only part way into a space under the core that TEPCO wants to inspect closely. 

It crawled down the passage while peeling debris with a scraper and using water spray to blow some debris away. 

The dark brown deposits grew thicker and harder to remove as the robot went further.

After about two hours, the two cameras on the robot suddenly developed a lot of noise and their images quickly darkened — a sign of a problem caused by high radiation.

 

The second robot, known as the ‘scorpion,‘ will also measure radiation and temperatures.

Thursday‘s problem underscores the challenges in decommissioning the wrecked nuclear plant. 

Inadequate cleaning, high radiation and structural damage could limit subsequent probes, and may require more radiation-resistant cameras and other equipment, TEPCO spokesman Takahiro Kimoto said.

We will further study (Thursday‘s) outcome before deciding on the deployment of the scorpion,‘ he said.

TEPCO needs to know the melted fuel‘s exact location and condition and other structural damage in each of the three wrecked reactors to figure out the best and safest ways to remove the fuel. 

It is part of the decommissioning work, which is expected to take decades.

During Thursday‘s cleaning mission, the robot went only part way into a space under the core that TEPCO wants to inspect closely. 

It crawled down the passage while peeling debris with a scraper and using water spray to blow some debris away. The dark brown deposits grew thicker and harder to remove as the robot went further.

After about two hours, the two cameras on the robot suddenly developed a lot of noise and their images quickly darkened — a sign of a problem caused by high radiation.

Operators of the robot pulled it out of the chamber before completely losing control of it.

The outcome means the second robot will encounter more obstacles and have less time than expected for examination on its mission, currently planned for later this month, though Thursday‘s results may cause a delay.

Both of the robots are designed to withstand up to 1,000 Sieverts of radiation. 

The cleaner‘s two-hour endurance roughly matches an estimated radiation of 650 Sieverts per hour based on noise analysis of the images transmitted by the robot-mounted cameras. 

That‘s less than one-tenth of the radiation levels inside a running reactor, but still would kill a person almost instantly.

Kimoto said the noise-based radiation analysis of the Unit 2‘s condition showed a spike in radioactivity along a connecting bridge used to slide control rods in and out, a sign of a nearby source of high radioactivity, while levels were much lower in areas underneath the core, the opposite of what would normally be the case. 

He said the results are puzzling and require further analysis.

TEPCO officials said that despite the dangerously high figures, radiation is not leaking outside of the reactor.

Images recently captured from inside the chamber showed damage and structures coated with molten material, possibly mixed with melted nuclear fuel, and part of a disc platform hanging below the core that had been melted through. 

https://insiderfinancial.net/robot-pulled-from-fukushima-reactor-due-to-radiation.html

December 8, 2019 Posted by | fukushima 2019 | , , | Leave a comment

Radiation levels inside Fukushima high enough to kill robot sent to clean

serveimage

December 6, 2019

A remote-controlled cleaning robot sent into a damaged reactor at Japan‘s Fukushima nuclear plant had to be removed Thursday before it completed its work because of camera problems most likely caused by high radiation levels.

It was the first time a robot has entered the chamber inside the Unit 2 reactor since a March 2011 earthquake and tsunami critically damaged the Fukushima Da-ichi nuclear plant.

Tokyo Electric Power Co. (TEPCO) said it was trying to inspect and clean a passage before another robot does a fuller examination to assess damage to the structure and its fuel. The second robot, known as the “scorpion,” will also measure radiation and temperatures.

Thursday‘s problem underscores the challenges in decommissioning the wrecked nuclear plant. Inadequate cleaning, high radiation and structural damage could limit subsequent probes, and may require more radiation-resistant cameras and other equipment, TEPCO spokesman Takahiro Kimoto said.

“We will further study (Thursday‘s) outcome before deciding on the deployment of the scorpion,” he said.

TEPCO needs to know the melted fuel‘s exact location and condition and other structural damage in each of the three wrecked reactors to figure out the best and safest ways to remove the fuel. It is part of the decommissioning work, which is expected to take decades.

The remote-controlled “cleaning” robot, bottom, was sent in to inspect and clean a passage for another robot in the damaged nuclear facility. (TEPCO/Associated Press)

During Thursday‘s cleaning mission, the robot went only part way into a space under the core that TEPCO wants to inspect closely. It crawled down the passage while peeling debris with a scraper and using water spray to blow some debris away. The dark brown deposits grew thicker and harder to remove as the robot went further.

More obstacles for second mission

After about two hours, the two cameras on the robot suddenly developed a lot of noise and their images quickly darkened — a sign of a problem caused by high radiation. Operators of the robot pulled it out of the chamber before completely losing control of it.

The outcome means the second robot will encounter more obstacles and have less time than expected for examination on its mission, currently planned for later this month, though Thursday‘s results may cause a delay.

Both of the robots are designed to withstand up to 1,000 Sieverts of radiation. The cleaner‘s two-hour endurance roughly matches an estimated radiation of 650 Sieverts per hour based on noise analysis of the images transmitted by the robot-mounted cameras. That‘s less than one-tenth of the radiation levels inside a running reactor, but still would kill a person almost instantly.

Kimoto said the noise-based radiation analysis of the Unit 2‘s condition showed a spike in radioactivity along a connecting bridge used to slide control rods in and out, a sign of a nearby source of high radioactivity, while levels were much lower in areas underneath the core, the opposite of what would normally be the case. He said the results are puzzling and require further analysis.

TEPCO officials said that despite the dangerously high figures, radiation is not leaking outside of the reactor.

Images recently captured from inside the chamber showed damage and structures coated with molten material, possibly mixed with melted nuclear fuel, and part of a disc platform hanging below the core that had been melted through.

https://livingstonledger.com/radiation-levels-inside-fukushima-high-enough-to-kill-robot-sent-to-clean/

December 8, 2019 Posted by | fukushima 2019 | , , | Leave a comment