Tepco checking debris fallen to bottom of Reactor No. 4 — May move control rods — ROV to be sent into Spent Fuel Pool

Published: March 12th, 2012 at 12:09 pm ET


Title: Survey on Distribution of Debris in Unit 4 Spent Fuel Pool, Fukushima Daiichi
Nuclear Power Station

Source: Tepco
Date: March 12, 2012

ROV*, which is controlled remotely and whose underwater camera is a self propelling is used for the survey on the distribution of debris in the spent fuel pool. 


We will through ROV in SPF through the slit of floats covering the pool. We operate it from the operating floor.


We are considering to move control rods currently stored in the cask pit to the bottom of Reactor in the future when we take out the fuel in SPF [sic]. We will survey debris fallen down to the bottom of Reactor to organize the plan.

Read the report here

Published: March 12th, 2012 at 12:09 pm ET


Related Posts

  1. Tepco prepares to film Spent Fuel Pool No. 4 — “You can vaguely discern the fuel rods” says worker February 10, 2012
  2. Tepco releases video of Spent Fuel Pool No. 4: Debris that fell on racks of fuel rods “apparently” caused no damage (VIDEO) February 10, 2012
  3. Japan Nuclear Expert: There are known to be broken fuel rod assemblies in Spent Fuel Pool No. 4 — Large amount of radioactive material has fallen to bottom — “Many years” to get fuel out (VIDEO) May 7, 2012
  4. Canadian Nuclear Scientist: Another, even more dangerous possibility than fire at Spent Fuel Pool No. 4 — Re-initiation of chain reaction can occur if fuel rods move slightly, an “accidental criticality” April 29, 2012
  5. Ex-Fukushima Worker: High risk they’ll break fuel rods in Unit 4 pool — Gundersen: Moving fuel risks nuclear chain reaction; You can’t stop it, no control rods to control it August 14, 2013

20 comments to Tepco checking debris fallen to bottom of Reactor No. 4 — May move control rods — ROV to be sent into Spent Fuel Pool

  • aigeezer aigeezer

    I hope somebody interviews "worker" (see the trolley at the top of the diagram) when he finishes his shift.

  • norbu norbu

    With #4 building so unstable is it safe to be messing around with this without re-enforcing the structure first. Hope they do not knock it it over!

  • norbu norbu

    Would not this be certain death for this human? And the supervisor off to the side. What are they doing? Testing there new toy robot? This is unreal.

  • NoNukes NoNukes

    I just heard an interview with a "Fukushima Worker" on Democracy Now, and he said that they are being paid $100 a day.

    I burst into tears.

    $100 a day??? For suicide?!! A waiter makes more than that at 4 star restaurants. The health care costs for his death will be so high!! What about the families they leave behind???

    Maybe they will pay this worker $150 a day?


    • Bobby1

      Being poor causes people to be targeted for extermination from the radioactive showers at the Fukushima Auschwitz.

      • NoNukes NoNukes

        Yes, Bobby1, Genocide doesn't happen as often to the rich, it is a phenomenon defined by class.

  • InfoPest InfoPest

    The idea of moving some of the fuel rods to the undamaged reactor could be a very good idea. It is one I did not consider. If the fuel rods are in a stable enough condition so they can be moved without crumbling and remain in that condition in the reactor then I would feel much safer about the state of Unit 4. The reactor is much stronger than the fuel pool and is less likely to lose it's ability to retain water. The only down side I see is if due to a future event the fuel crumbles to the bottom of the reactor it would then be in a bowl shape configuration which would be harder to cool and more likely to go out of control.

  • truthseek truthseek

    I don't buy it, sounds like and utterly BS story.
    Too unsafe on many levels…

    Like 6 & 10 o'clock infotainment News.
    Creating content… The story.

  • jec jec

    Sounds like a plan of some sort. At least if the reactor WAS previously full of fuel they will be able to check it out. Rumors should be dispelled. And moving the fuel to the containment vessel, looks like it would be almost a water to water transfer. Other question..what are the fuel rod "housings" like? Do they move rod by rod..or by groups? All things they will work thru. Rushing is not a good idea unless they fear a major earthquake.

    IF the Reactor 4 situation is as dire as some say, then collapse and MOX releases would make most of the Northern Hemisphere toxic. So maybe that is a reason for the media silence. Wonder if the powers that be fears the public will head to South America or Africa before the heads of government get to relocate. Or not…

  • Atomfritz Atomfritz

    Great, hope we get detailed footage of the SFP 4 contents soon.

    @ InfoPest

    They don't dump fuel rods into the reactor well, just control rods which aren't that radioactive.

    @ norbu

    A few millisievert is no big deal. Even a kitten would survive this.

    Better look at America.
    2000 people going to be "burnt" in Quad Cities NPP soon:

  • norbu norbu

    My parent live near the quad cities whats going down there?

  • PhilipUpNorth philipupnorth

    Please be alert to the fact that there are new MOX rods, the ones with plutonium in them, in SFP #4. The bundles should have been widely dispersed throughout the pool for safety reasons, and in accordance with TEPCO SOP, but were placed adjacent to each other. My guess is that they thought there would be no harm, since the new rods were to go into reactor 4 right away. Instead, they are still in SFP4 a year later, and these new MOX fuel rods constitute the primary threat at the Fuku disaster site. This is why they are working so hard to relocate these rods to a more stable location.

    • dosdos dosdos

      The fresh rods in SFP 4 are LEU. Only Unit 3 was converted to run MOX. There is no MOX in the Unit 4 building.

  • AGreenRoad AGreenRoad

    Better get it done before the 22nd.. Large probability of HUGE Earthquake coming, to someplace on Earth… could be Japan, could be somewhere else. Watch the video and decide if this logic makes sense… it made sense to me..


  • vital1 vital1

    There is a lot of debate as to the condition of SFP4. The enenews webcam forum observers have felt the fuel rods in SFP4 where on fire at least a couple times late December 2011 /January and February.

    So is this just a TEPCO PR exercise in response the Japanese TV show featured in this enenews article posted couple days ago. This enenews article also had around 11,000 views.


    If they can move the SFP4 mess into the old reactor container that would be a good start at stabling the SFP4 situation. This operations success will greatly depend on the condition of the fuel rods in SP4. I have seen estimates ranging from 1300 to 1500 fuel rods being stored in SFP4.

    As philipupnorth stated "There are new MOX rods, the ones with plutonium in them, in SFP #4".

    To me this is just like dancing a around a camp fire singing songs. Nothing actually changes just the appearance of something positive happening.

    There needs to be a large scale worldwide engineering effort to get on top of this.

    They should forget their pride and invite worldwide help!

  • evendine

    The problem is that SFP4 was levelled by the explosions and is incapable of holding water. This led to a zircalloy fire (impossible to extinguish) which started prior to the 15th of March last year.

    TEPCO and co are simply lying about it – the whole thing…

    There's incontrovertible evidence of this in the NRC archive of conversations amongst their staff at the time:

    See: http://enformable.com/2012/03/nrc-transcript-tepco-relayed-information-unit-4-sfp-dry-walls-collapsed-and-incapable-of-holding-inventory-unit-3-everything-else-gone/

    and also p.63 onwards:


    The photographic evidence previously published on this blog backs this position up. Perhaps dissenters could provide an image taken by an independent source which shows an intact fuel pool from the outside?

  • dosdos dosdos

    Getting the fresh LEU from SFP 4 to reactor vessel 4 would be a smart move. If they do nothing but move the fresh fuel into the reactor so they could better cool it and protect it from quake damage, it would be a huge improvement.

    Yes, it would be nice to get it all, but if it's possible, get the freshest fuel first, and progressively move the older fuel into the reactor until something stops the process.

    Now much depends on the condition of the contents of SFP 4. It might be a futile gesture, but it might not. But considering what could happen if the fresh fuel spills, it's worth a try. That is, if it's a genuine try….