Photos: Large device that fell in Fukushima Unit 3 pool was “found on the fuel rack” — “Apparently narrowly avoided striking and damaging liner”

Published: February 13th, 2013 at 10:13 am ET


Title: Investigation of the Inside of Spent Fuel Pool Utilizing an Underwater Camera as Part of Debris Removal from the Upper Part of Unit 3 Reactor Building at Fukushima Daiichi Nuclear Power Station
Source: Tokyo Electric Power Company
Date: February 13, 2013

The fuel handling machine mast’ was found on the fuel rack and was not directly contacting the spent fuel storage rack and the liner”

Enformable: “The 1.5 ton device was found resting on top of the fuel racks, where it apparently narrowly avoided striking and damaging the liner of the spent fuel pool. The utility did not release any data related to measurements of radioactive materials in the spent fuel pool which would likely show an increase if spent fuel assemblies had been damaged.”

See also: [intlink id=”video-large-piece-debris-dropped-fukushima-unit-3-fuel-pool-during-snowstorm” type=”post”]{{empty}}[/intlink]

Published: February 13th, 2013 at 10:13 am ET


Related Posts

  1. Asahi: Tepco to check for “smashed fuel rods” after large piece of debris fell at Fukushima Unit 3 pool February 8, 2013
  2. Footage of large piece of debris dropping into Fukushima Unit 3 fuel pool during snowstorm (VIDEO) February 10, 2013
  3. Confirmed: 35-ton machine “sitting on top of the spent fuel rack in the pool” of Reactor No. 3 — Extent of damage not yet known (VIDEOS) April 17, 2012
  4. Tepco: Debris is missing at Unit 3 — May have ‘sunk’ into fuel pool (PHOTOS) February 7, 2013
  5. Tepco concerned about liner of No. 3 Spent Fuel Pool at Fukushima plant? (PHOTOS) December 19, 2012

12 comments to Photos: Large device that fell in Fukushima Unit 3 pool was “found on the fuel rack” — “Apparently narrowly avoided striking and damaging liner”

  • guezilla

    Is there anybody else blinking their eyes and trying to decipher and understand "The fuel handling machine mast* was found <em>on the fuel rack</em> and was <em>not directly contacting the spent fuel storage rack</em>", or is it just the radiation getting to me?

    Although it seems impossible to make out the actual fuel racks in either of the images, so maybe they mean it's okay because it fell on all the debris they'd wisely deposited on the top of the fuel racks prior? 🙂

  • PhilipUpNorth PhilipUpNorth

    Reposted from earlier thread, but on topic here:
    SFP3 has so much debris on top of the spent fuel racks that none of the handles can be seen in the new photos, that I can spot amid the rubble. In uranium fuel assemblies, the handles extend above the top of the fuel racks, as can be seen in this photo of SFP4.
    We have already seen that a great amount of damage to fuel assemblies and fuel racks occurred from falling debris at SFP4.
    In the following photo of SFP4, a rack of MOX fuel in the center of the picture shows that MOX fuel assemblies extend even further above the protection of the fuel racks than uranium fuel assembly handles.
    We can expect many of the spent fuel assemblies in SFP3 to be heavily damaged when the last of the debris have been removed from the pool. Before SFP3 fuel removal is complete, there may be piles of fuel pellets scattered all over the floor of the pool, sparking constant criticalities, and making those tungsten vests useless.

    • Sickputer

      >making those tungsten vests useless

      SP: They are already useless… Just a psychological crutch for the banzai workers.
      Radiation rips upward from below into their feet, legs and mid section. These 21st century rooftop Liquidators will all be dead within ten years.

      Internal organs will be destroyed… same horrible urinary and reproductive debilitation as seen at Chernobyl. These men will never have progeny and will die pain wracked, broke, and abandoned by their government. More suicide workers will have to replace them.

  • Reactor Reactor

    Is the bluish tint to the photos due to Cherenkov radiation? If so, what can we infer is going on underwater and how lethal the radiation levels are there?

  • Guys..? This is the #3 pool before it exploded.

    The MOX is the covered stuff on upper left. The lower the Uranium… All the others are like the ones in center of #4 pool… Plutonium breeders as you can clearly see.

    The Rods tucked into corners of the pool are what's blasted remains now. The ones near the large gate to the core are the only semi-intact rods in the pool… and they are standard ones.

    This shows where the rods are consumed entirely.

  • PhilipUpNorth PhilipUpNorth

    What happens when fuel assemblies fail, dumping their fuel pellet contents onto the floor of a spent fuel pool?
    Each fuel assembly contains perhaps half a ton of fuel pellets. The fuel assemblies have been subject to explosions, raining debris, burning, seawater, and even fallen steel. What do you think is going to happen during fuel removal at Fukushima? Answer: A bunch of spent fuel assemblies are going to break open, spilling fuel pellets all over the floor of the pool. What then?

    To answer this question, I went back to a paper comparing modern nuclear reactors to the natural reactors that used to operate naturally in what is now an abandoned uranium mine in Oklo, Gabon.
    My conclusion from reading this paper is that spilled spent fuel pellets in water will almost certainly reach criticality, and could even reach supercriticality. The peoblem with this is that SFP1,2,3,&4 at Fukushima are open to the air. There are no control rods, reactor, containment, or building to keep fission under control and contained. This is going to get very interesting as we get into the fuel removal phase of the "clean-up".

    • PhilipUpNorth PhilipUpNorth

      "At the time that the Gabon reactor went critical, the abundance of 235U was 3%, similar to that in current commercial nuclear reactors. The approximate shape of the reactor zones is that of a compact mass of uranium oxide surrounded by porous rocks, which were presumably hydraulically connected to surface or ground water, allowing moderation and reflection of the neutrons produced by spontaneous fission or cosmic ray induced fission.
      The relatively large size and spherical shape of the uranium bearing region reduced buckling. When the surrounding porous rocks were saturated with water, the subsequent moderation and reflection allowed the reactor to achieve criticality." Last revised 4/16/05 Page 6 of 9

      To me, this description sounds a lot like a description of Corium1,2,&3, in the sandstone under Buildings1,2,&3 at Fukushima. A compact mass of uranium and plutonium, encased in sandstone, with plenty of ground water for neutron moderation. It is estimated that the Gibon Natural Reactors were periodically critical over 150,000 years. Unless something is done to contain the errant Fukushima corium, this is what will almost certainly occur over a geological timeframe at Fukushima.

    • Okay!.. Few things to remember… U-238/ 235 can not go super critical without human help.. IE, an implosion or explosive-gun of right element into it. Plutonium, however… doesn't have this problem! 10.5 kilo of Pu-239 gets together… you get super critical event! But Pu-241..? It only take 5.2 kilos to have same thing happen! Pu-240 however.. captures neutrons… and causes a fizzle… like what happened in #3's pool.

  • razzz razzz

    Unit 3's liner was already damaged by falling pieces of the building during the explosion as in areas the stainless steel liner was bent/peeled away from its concrete support walls and later repairs attempted by injecting hardening foam in the void space between the liner and concrete to reestablish support for the SS liner wall.

    The fuel racks contains partitions filled with neutron absorbing boron to keep the fuel rods assemblies from reacting and heating up besides the water to carry off decay heat. The repacking of fuel esp. #4 makes the crowding of fuel assemblies as dense as if they were configured in a reactor core…Boron is your friend.

    I am sure they add boron to the cooling pool waters to prevent any loose fuel pellets and loose zirconium rods from causing further fissioning if they are laying around the bottom of the pool somewhere, doesn't stop the release of spent fuel byproducts but does prevent reactions.

    The cooling water traps most but not all the waste fission byproducts which can be mostly filtered out in normal conditions. But with tons of debris in and above the pool water, it has all been irradiated esp. during the explosion then during uncontrolled releases like steaming. Be interesting to see if they can ever approach #3 like #4. So far at #3 you get a dense vest and a pat on the back.

  • razzz razzz

    Oops. Need to have the above moved to off-topic forum…