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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

• 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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