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Utility's Pictures Likely Show Melted Fukushima Fuel for First Time

posted by martyb on Sunday July 23 2017, @10:53AM   

takyon writes:

https://www.bloomberg.com/news/articles/2017-07-22/japan-pictures-likely-show-melted-fukushima-fuel-for-first-time

New images show what is likely to be melted nuclear fuel hanging from inside one of Japan's wrecked Fukushima reactors, a potential milestone in the cleanup of one of the worst atomic disasters in history.

Tokyo Electric Power Co. Holdings Inc., Japan's biggest utility, released images on Friday showing a hardened black, grey and orange substance that dripped from the bottom of the No. 3 reactor pressure vessel at Fukushima, which is likely to contain melted fuel, according to Takahiro Kimoto, an official at the company. The company sent a Toshiba-designed robot, which can swim and resembles a submarine, to explore the inside of the reactor for the first time on July 19.

"Never before have we taken such clear pictures of what could be melted fuel," Kimoto said at a press briefing that began at 9 p.m. Friday in Tokyo, noting that it would take time to analyze and confirm whether it is actually fuel. "We believe that the fuel melted and mixed with the metal directly underneath it. And it is highly likely that we have filmed that on Friday."

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Original Submission

• Dead knowledge, Failure To Learn Dead knowledge, Failure To Learn (Score: 4, Interesting) by requerdanos on Sunday July 23 2017, @07:26PM (4 children)

  by requerdanos (5997) on Sunday July 23 2017, @07:26PM (#543436) Journal

  For the record, reality has proven beyond the shadow of a doubt that it was stupid, stupid, criminally stupid, to build so close to the sea.

  What's been proven is that regardless of where it was built, it was a bad idea to put the generators in a basement. Even atop the world's highest mountain, hundreds or even thousands of meters higher in altitude, the smallest-scale localized spill that can flood *just the basement* renders the generators inoperable, and in a power failure, leads inexorably to loss-of-coolant and meltdown.

  This was a concern even before the tsunami [japantimes.co.jp], concerning at any altitude:

  Yukiteru Naka, [who] took part in designing and operating reactor units [at Fukushima], is just one of a few engineers whose knowledge spans the facility’s 40-year history. Naka recalls [a lingering question]: Why were the backup emergency diesel generators and DC batteries still located in the turbine buildings’ basements? “If an earthquake hits and destroys some of the pipes above, water could come down and hit the generators... Many of the middle-ranking engineers at the plant shared the same concern.”

  Whereas, built in Godzilla territory right on the shore, while being actively shaken by earthquakes and actively inundated by tsunami, having the generators located just a few meters higher up than the basement would have caused the whole event to have been a minor blip on the world's radar, long-forgotten even by Japan.

  Locating backup air-cooled diesel generators in basements, for example, was a sign that Fukushima wasn’t fully prepared for a tsunami, says Tony Irwin, a lecturer in nuclear technology...

  - Technologyreview.Com [technologyreview.com]

  If the emergency generators had been installed on upper floors rather than in basements, for example, the disaster would have stopped before it began.

  - IEEE, "24 Hours at Fukushima" [ieee.org]

  Placing the critical generators in the basements of the turbine buildings left the plant vulnerable to the tsunami threat...
  “This accident would have been prevented if the generators had been placed inside the (more tightly sealed) reactor buildings [instead]...” said Masatoshi Toyota, a former senior vice president of Tepco.

  - The Japan Times, July 14th, 2011 [japantimes.co.jp]

  It would border on criminal for us as a people to come away with lesson here that it's ok to build it wrong, as long as you build it far away from one or two types of potential threat. And "mountain-not-sea" thinking leans very troublesomely in that direction.

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• No thanks (Score: 2) by snufu on Monday July 24 2017, @01:57AM

  by snufu (5855) on Monday July 24 2017, @01:57AM (#543550)

  All your regulations just kill jobs. You don't want to kill jobs do you? Who cares if we introduced a new form of orange radioactive metal into the sea. Think of it as TEPCO's glowing coral reef. Charge admission for snorkling.

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• Re:Dead knowledge, Failure To Learn Re:Dead knowledge, Failure To Learn (Score: 2) by kaszz on Monday July 24 2017, @06:39AM (1 child)

  by kaszz (4211) on Monday July 24 2017, @06:39AM (#543588) Journal

  Why were the backup emergency diesel generators and DC batteries still located in the turbine buildings’ basements?

  Exactly. The question then becomes why were it designed to be there in the first place? Why didn't management do anything about it?

  And have nuclear power facilities even learnt their lesson by now to place backup generators high enough to lower the chance of flooding and made them such that if they are flooded they are located in a water tight building with a snorkel to handle high level flooding like any WWII submarine could?

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  • Re:Dead knowledge, Failure To Learn (Score: 2) by requerdanos on Monday July 24 2017, @01:37PM

    by requerdanos (5997) on Monday July 24 2017, @01:37PM (#543668) Journal

    The question then becomes why were it designed to be there in the first place? Why didn't management do anything about it?

    These reactors were designed in the United States of America by GE. As for why they were designed with backup generators in the basement, that designer, Yukiteru Naka [japantimes.co.jp] opines that it was a Japanese sea vs. American river mindset:

    Former GE engineer Naka pointed out that most of GE’s boiling water reactors — the same type as unit 1 at Fukushima No. 1 — in the United States were built along rivers to take in coolant water, not near the sea. “So GE’s design concept did not put much emphasis on tsunami,” he said.

    That doesn't mean it was a good design; reactors like that go through a lot of water and if it leaks into the basement, goodbye generators. But that seems to have been the thinking.

    And why wasn't the design changed? Because TEPCO didn't feel comfortable changing GE's designs. From that same article:

    ...plant operator Tokyo Electric Power Co. did not allow any alteration to the U.S. company’s blueprints... Some engineers long had concerns over this apparent misplacement of the critical backup power systems. But Tepco, conservative by nature, didn’t allow the Japanese companies building the plant to make any alterations to GE’s basic design, said Tadaharu Ichiki, a 75-year-old former nuclear plant designer at Toshiba Corp. “That had been the tradition at Tepco. When Tepco introduced thermal plant technologies from overseas, (the utility’s executives) also told the Japanese makers to build the plants exactly in the same way as those of foreign makers,” Ichiki said. “Tepco was very bureaucratic.”

    I suppose the idea was that since GE was more experienced in designing and building nuclear power plants, that safety might be compromised if less-experienced TEPCO or its contractors changed the designs. Sure didn't work out that way.

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• Re:Dead knowledge, Failure To Learn (Score: 0) by Anonymous Coward on Monday July 24 2017, @11:04AM

  by Anonymous Coward on Monday July 24 2017, @11:04AM (#543631)

  And if the emergency generators where built as dry reservoir of a mini hydro-plant with turbines and generators, tsunami flooding would had provided instant emergency energy to it.

  The backup mini hydro could had been even used in constant operation, letting the nuclear plant supply the energy for pumps to keep the reserve full at all times, so that there is never a need for a switch mechanism. If it malfunctions, you immediately know.

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