Stories
Slash Boxes
Comments

SoylentNews is people

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

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

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."

Original Submission

 
This discussion has been archived. No new comments can be posted.
Utility's Pictures Likely Show Melted Fukushima Fuel for First Time | Log In/Create an Account | Top | 49 comments | Search Discussion
Display Options Threshold/Breakthrough Mark All as Read Mark All as Unread
The Fine Print: The following comments are owned by whoever posted them. We are not responsible for them in any way.

  • (Score: 1) by khallow on Monday July 24 2017, @12:25AM (6 children)

    by khallow (3766) Subscriber Badge on Monday July 24 2017, @12:25AM (#543526) Journal
    Sorry, that report doesn't cover tsunamis.

    The Japanese Nuclear Safety Commission publishes a report dated 11 June 1993, (Heisei 5) whose title literally translates to The event of entire alternating current station blackout on the nuclear power plant (原子力発電所における全交流電源喪失事象について) conducted by a working group. This reports the results of an evaluation of the regulations to prevent and handle an occurrence of the full loss of alternating current (Station Blackout or SBO) in nuclear power plants in Japan and other countries. It concludes that further discussion is needed on methods to avoid or recover from such accidents. It also reports that the probability of an SBO in Japan is lower than in other countries

  • (Score: 2) by RamiK on Monday July 24 2017, @07:11AM (5 children)

    by RamiK (1813) on Monday July 24 2017, @07:11AM (#543595)

    Tsunamis are part of cascading seismic events. The 1993 report (which deals with Station Blackouts) asses everything should be fine as long as grid power is restored within a few hours since the on-site batteries are good for 4 hours which is enough time to start the emergency diesel generator.

    However, as the committee chairman commented on protocol, those weren't reasonable assumptions. Even disregarding direct earthquake damage to the plant, although there weren't any past grid cutoff incidents extending over 30min in Japan, anyone with a lick of sense would know those can, and will happen eventually. They even had multiple separate codes for equipment like the emergency diesel generators that required continuous operation precisely because separate regulatory bodies assessed days and even weeks worth of potential localized power losses. And any power loss is unacceptable when it takes spent fuel rods a decade to cool off in circulating water pools, let alone partially spent rods in standing water...

    --
    compiling...

    • (Score: 1) by khallow on Monday July 24 2017, @09:31AM

      by khallow (3766) Subscriber Badge on Monday July 24 2017, @09:31AM (#543618) Journal
      Ok, I don't see that as relevant to my prior concern. The above was a known flaw of that generation of nuclear plants from its inception. Instead, the sentence I quoted claims a specific knowledge of larger tsunami risk than originally planned at the Fukushima site from research 18 years ago. So yes, it would have been some sort of research from 1993, but one which addressed the increased tsunami risk rather than the active cooling requirement and related issues of the reactor design.

    • (Score: 1) by khallow on Monday July 24 2017, @09:53AM (3 children)

      by khallow (3766) Subscriber Badge on Monday July 24 2017, @09:53AM (#543622) 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 when a Japan Society of Civil Engineers paper [telegraph.co.uk] was released (I can't find the original paper, but the speaker "said a 2002 report by the Japan Society of Civil Engineers described the dangers posed by a tsunami wave of around 20 feet."). TEPCO, the Fukushima plant operator had issued an updated assessment [dailycaller.com] of the tsunami risk in 2001 (which tersely downplayed the risk).

      The New York Times wrote a story where they claim that the lessons [nytimes.com] of a western Japan earthquake in 1993 should have been learned (though not why that was supposed to be a lesson - should every nuclear plant in the world near water engineer for 10 meter high tsunami?). Once again, no actual research cited until the above mentioned 2002 paper.

      If there really was research from 18 years ago, you'd think the variety of media sources out there would have cited it by now.

      • (Score: 2) by requerdanos on Monday July 24 2017, @01:52PM (2 children)

        by requerdanos (5997) Subscriber Badge 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.

        • (Score: 1) by khallow on Monday July 24 2017, @10:38PM (1 child)

          by khallow (3766) Subscriber Badge on Monday July 24 2017, @10:38PM (#543914) Journal
          How visible were their "lingering questions"?

          • (Score: 2) by requerdanos on Monday July 24 2017, @11:59PM

            by requerdanos (5997) Subscriber Badge 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]