Fukushima reactor 3 meltdown was worse than estimated: Tepco


Staff Writer

Tokyo Electric Power Co. said Wednesday that its new estimate shows that all the fuel rods in reactor 3 at the Fukushima No. 1 nuclear power plant apparently melted down and fell onto the bottom of the containment vessel.

In November 2011, the company had said it believed only about 63 percent of reactor 3’s fuel core had melted.

The utility updated its estimate as part of an effort to probe unclear points about the triple meltdown at the Fukushima No. 1 plant caused by a megaquake and monstrous tsunami in March 2011.

The revised estimate is based on the finding that an emergency cooling system, known as HPCI, of reactor 3 stopped working six hour earlier than previously thought, and that the meltdown had also started more than five hours earlier.

Tepco had previously said that the HPCI had shut down at 2:42 a.m. on March 13, 2011. But further investigation over the past year determined that the HPCI appeared to have lost its cooling function about at 8:00 p.m. on March 12.

According to the new estimate, all the melted fuel penetrated the pressure vessel, fell onto the bottom of the containment vessel and melted about 68 cm into the concrete.

The pressure vessel is located inside the massive containment vessel.

The analysis shows that the fuel did not penetrate the containment vessel, according Tepco.

While the new analysis announced on Wednesday, based on temperature, pressure and other data, shows that all the fuel had melted down to the containment vessel, Tepco has a more optimistic view.

“We think some fuel still remains at the core part based on the actual plant data,” said Shinichi Kawamura, a Tepco spokesman, during a news conference.

According to Kawamura, this is because the temperature of the pressure vessel decreased when the water was injected, meaning some warm fuel was still there.

  • xexon

    Worse than estimated or worse that what you were told? Big difference.

    The only real certainty is the reactors will continue to emit radiation for years. With it contaminating sea water the whole time. For a nation so dependent on a fish diet, this is bad news.


  • RokinRobin

    It was only worse than the lying corporation TEPCO disclosed.

    Scientists all over the world said as much from the beginning.

  • grindermonkey

    I don’t know why TEPCO even makes statements to the press. No one on the planet gives them any credence whatsoever. This disaster is the very nadir of the unknown and no prior predictions have proved reliable.

  • crash2parties

    And in a few months, they’ll release updated estimates that show some small percent may have burned through the bottom of the containment vessel…
    and a few months after that, some tiny little percent of the plant’s fuel might have burned up into the air, creating “negligible fallout”.

  • badforu

    What does it matter, ask anyone, radiation has never killed anyone. Outside of them talking that smack… still no one is responsible and no one is held accountable for the accident and the preceding and ongoing subversion. That is the reality we are left with. Even when they come out with the deaths tokyo and surrounding area, it will still be ok with everyone. Glad i dont live in Japan. Still feel sorry for the children of the world that will grow up in in it.

  • UncleB

    Possibly three corium missing! Time left to examine the safety of the original “Enriched Uranium” designs over the original Thorium LFTR styled systems? China thinks so and spends money now researching safer cleaner more efficient Thorium systems, but continues building huge numbers of the older dangerous type reactors? Plutonium, the final Planet Poison – unknown on earth until the 1940’s. Atmospheric nuclear explosions banned due to just how dangerous Plutonium is to all human life. Google Plutonium just for interest’s sake.