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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 Ocean, Dying Planet Re:Dead Ocean, Dying Planet (Score: 2) by requerdanos on Monday July 24 2017, @01:52PM (2 children)

  by requerdanos (5997) on Monday July 24 2017, @01:52PM (#543680) Journal

  To continue my point here, I've been googling for stories on what was known prior to the 2011 earthquake about the tsunami risk of the Fukushima site. I have yet to see a reference to anything before 2002

  This isn't a zomg-tsunami, but it's a specific related concern (basement flooding risk) unearthed from more than 18 years prior:

  Yukiteru Naka, a former employee of General Electric who took part in designing and operating reactor units 1, 2 and 6 at the Fukushima No. 1 nuclear power plant, is just one of a few engineers whose knowledge spans the facility’s 40-year history.

  Naka recalls that he and many of his colleagues had a lingering question about the plant at least since the mid-1980s: 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. DC batteries were also located too close to the diesel generators,” said Naka, who now runs Tohoku Enterprise Co., a Fukushima-based maintenance company for nuclear plants. “It’s not at all good in terms of safety. Many of the middle-ranking engineers at the plant shared the same concern.”

  - Japan Times, 14 July 2011 [japantimes.co.jp], emphasis added.

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• Re:Dead Ocean, Dying Planet Re:Dead Ocean, Dying Planet (Score: 1) by khallow on Monday July 24 2017, @10:38PM (1 child)

  by khallow (3766) on Monday July 24 2017, @10:38PM (#543914) Journal

  How visible were their "lingering questions"?

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  • Re:Dead Ocean, Dying Planet (Score: 2) by requerdanos on Monday July 24 2017, @11:59PM

    by requerdanos (5997) on Monday July 24 2017, @11:59PM (#543943) Journal

    How visible were their "lingering questions"?

    I haven't personally researched that, but they were Pretty Darn Visible, per wikipedia:

    On 30 October 1991, one of two backup generators of Reactor 1 failed, after flooding in the reactor's basement. Seawater used for cooling leaked into the turbine building from a corroded pipe at 20 cubic meters per hour, as reported by former employees in December 2011. An engineer was quoted as saying that he informed his superiors of the possibility that a tsunami could damage the generators. TEPCO installed doors to prevent water from leaking into the generator rooms.

    The Japanese Nuclear Safety Commission stated that it would revise its safety guidelines and would require the installation of additional power sources. On 29 December 2011, TEPCO admitted all these facts: its report mentioned that the room was flooded through a door and some holes for cables, but the power supply was not cut off by the flooding, and the reactor was stopped for one day. One of the two power sources was completely submerged, but its drive mechanism had remained unaffected.

    https://en.wikipedia.org/wiki/Fukushima_Daiichi_nuclear_disaster#1991:_Backup_generator_of_Reactor_1_flooded [wikipedia.org]

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