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After Alarmingly High Radiation Levels Detected, What Are the Facts in Fukushima? via National Geographic

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Recently Tokyo Electric Power Company (TEPCO) began sending robotic cameras into the primary containment vessels (PCV) that house the damaged reactors. However, due to extremely high levels of radiation, the robots keep breaking. Within the last two weeks, two cameras have broken—including the one on a scouting mission for the robot meant to locate the radioactive fuel.

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To find out more, I contacted Safecast, a citizen science network that bills itself as neither pro-, nor anti-nuclear. Safecast’s team of volunteers have developed the bGeigie handheld radiation monitor, that anyone can buy on Amazon.com and construct with suggested instructions available online. So far over 350 users have contributed 41 million readings, using around a thousand fixed, mobile, and crowd-sourced devices.

Here is what Azby Brown, Safecast’s lead researcher, has to say in an interview.

Let’s recap. TEPCO sent in a robot, it captured pictures before frying, and they stitched the photos together and found the hole. Inside the hole are extremely high levels of radiation, higher then ever measured before. They believe this is THE hole, created by melting radioactive material.

The first step in TEPCO’s recent investigations deep inside Unit 2’s reactor was to insert a camera on a long telescoping pole through an existing maintenance opening. It was not a robot. It captured striking images of what appear to be melted metal spattered on floor decking and other elements inside. They also detected a hole in the steel floor decking about 1m by 1m [about 10 square feet]. They were not able to actually see a hole in the steel reactor pressure vessel (RPV) above, but the working assumption is that the hole in the decking was caused by molten core material mixed with steel falling through.

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A few days after the telescoping-arm investigation, a small-tracked cleaning robot with a high-pressure water nozzle and a scraper was inserted.  This operated for 2 hours before the radiation had degraded the camera too much to continue. Neither the telescoping unit nor the cleaning robot had an actual radiation detector, and radiation levels were inferred from camera noise and degradation of the cameras. TEPCO’s first announcement was that radiation levels were estimated to be as high as 530 Sv/hour; the succeeding estimate was over 600 Sv/hr. Either would be fatal to a human after a few minutes’ exposure.

Finally, on Feburary 16, Tepco inserted a second robot into the reactor. This one is called the “Scorpion” because it has a folding “tail” containing powerful lighting and a camera. It operated well for about 30 minutes before becoming disabled, but was able to obtain about 6 hours of video images as well as better radiation measurments, which showed maximum levels of about 210 SV/hr. While this is lower then the previous estimates, it is also considered more accurate and within an order of magnitude. It would also be fatal to humans after a few minutes’ exposure.

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Is the radiation contained? From where is the radiation still leaking? 

It’s not fully contained, in that some of the recirculated cooling water, which becomes contaminated by contact with the core material, leaks out of the building, presumably through cracks in the basement walls of the reactor. Lots of measures have been taken to try to contain and minimize this, but none have been fully successful yet. Many of the steps being taken now are to prepare for locating and closing these leaks. This will be several years in the future at best, however.

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In the era of fake news and misinformation, what can people do to verify these results for themselves? 

There’s no substitute for doing the homework, becoming technically and media-literate, and informing oneself. Radiation issues are largely scientific, but as we’ve seen in the current political situation in the U.S., other issues are ripe for abuse and manipulation as well. We encourage people everywhere to be skeptical and to become skilled at fact-checking. This is only possible with adequate education.

As far as radiation and Fukushima are concerned, it’s usually pretty obvious when a website is distorting or manipulating information. But we’ve seen good journalists fall prey to bad info as well.

Read more at After Alarmingly High Radiation Levels Detected, What Are the Facts in Fukushima? 

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Continuing the Discussion

  1. Fukushima Accident: Challenges and Lessons | Centre for Strategic and Contemporary Research linked to this post on 2019/11/25

    […] so, Japan designed the robotic cameras to sustain the radiations levels, even those robots then got crashed due to overwhelming impacts of the […]



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