Asahi: Most delicate work since 3/11 — Tepco removing nuclear fuel “to confirm whether it’s damaged” (NEW PHOTOS)

Published: July 18th, 2012 at 4:02 am ET
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26 comments


(Subscription Only) Title: TEPCO removing fuel from Fukushima No. 4 reactor on trial basis
Source: Asahi Shimbun
Date: July 18, 2012

Asahi Shimbun

Tokyo Electric Power Co. has begun work to remove unused nuclear fuel from the storage pool of the No. 4 reactor

[…]

It marks the first time that TEPCO has endeavored such delicate work since the onset of the disaster triggered by the Great East Japan Earthquake of March 11, 2011.

Full-scale work to remove fuel is not expected until December 2013.

[…]

TEPCO will remove two unused fuel units in separate procedures on July 18 and 19 to confirm whether they are damaged.

[…]

REUTERS/Kyodo

Published: July 18th, 2012 at 4:02 am ET
By

26 comments

Related Posts

  1. Tepco to remove fresh fuel from No. 4 pool this summer — “Hoping to determine how damaged unused assemblies are” May 28, 2012
  2. Sources: Unit 4 fuel assembly to be ‘cleaned’, not yet in shared pool — Tepco declines to comment — Trying to determine how much cladding has been eroded or damaged by seawater (NEW PHOTO) July 18, 2012
  3. Kyodo: Spent Fuel Pool No. 4 visibility deteriorating — Major drop over past month — No where near what’s needed “to work at removing nuclear fuel” March 15, 2012
  4. WSJ speculates: “Is process of emptying the Unit 4 pool starting?” — Will Tepco continue taking out more racks? — Law forbids disclosing when nuclear fuel is moved July 19, 2012
  5. TV: “Japan’s worst nuclear nightmare” — Yale Professor: Removing fuel from Fukushima Unit 4 pool “has me very scared” — Tepco: “We believe it’s not dangerous” (VIDEO) October 31, 2013

26 comments to Asahi: Most delicate work since 3/11 — Tepco removing nuclear fuel “to confirm whether it’s damaged” (NEW PHOTOS)

  • mungo mungo

    good luck to the workers

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  • PhilipUpNorth philipupnorth

    Lots of workers on Building4 yesterday. The work may already be finished.

  • Sickputer

    I am not OCD, but it is better to use the terms nuclear rod units or nuclear rod assembly.

    In a BWR (Boiling Water Reactor) like Daiichi there are three generations of design and Units 1-5 were the oldest generation (Mark 1) and Unit 6 is the second generation (Mark 2). One of the differences from 1 to 2 is a Mark 2 has about 50% more boron control rods and like all BWRs these rise and lower through holes in the reactor core vessel. Boring stuff until meltdowns occur and suddenly the holes offer an easier egress from the first line of containment.

    The fuel rod assemblies ( which is what they refer to when they say they are removing two) contain 63 skinny nuclear rods about 12.5 feet in length and packed with bullet-sized nuclear pellets. Tthe assembly has an 8 by 8 hole array and I don't know why one hole is left unfilled (patb ?).

    The 63-rod assemblies are inserted into the much bigger core assembly that holds 400 of these smaller assemblies. That's about 25,000 nuclear rods. Over time the 63-rod assemblies are reshuffled in the core to achieve more efficient fission. In time they lose the desired efficiency and are pulled from the big core assembly and "retired" to the nearby spent fuel pond. Because they now have much more radiation leakage they can't be removed from deep water for years.
    They built up until the pond holds the current estimated 3,450 fuel assemblies (217,000 rods). That's just in Unit 4's spent fuel pond. Two of the safest were just…

    • patb2009

      "The fuel rod assemblies ( which is what they refer to when they say they are removing two) contain 63 skinny nuclear rods about 12.5 feet in length and packed with bullet-sized nuclear pellets. Tthe assembly has an 8 by 8 hole array and I don't know why one hole is left unfilled (patb ?)."

      as i was asked, I will venture that the center hole is left empty to allow a control rod to come down,
      or allow a crculation of water.what's odd is if they wanted to make the math easier these wouldnt be aquare bundles but hexagonal

  • Sickputer

    …removed. 3,448 more to go.

    • aigeezer aigeezer

      That's useful, Sickputer. I had been wondering about possible media conflation of "rods", "assemblies", "fuel", and so forth. Thanks!

    • mungo mungo

      • The total number of spent fuel rods across all six reactors at the Fukushima Daiichi site is 11,421.

      • fredlvie

        most of them (those from reactor 1+3)have been disintegrated,molten and blown into the air in the explosions that occured then…

      • PhilipUpNorth philipupnorth

        mungo, you are still confusing fuel rods and fuel assemblies. Please learn the difference: read SP post. You meant to say "fuel assemblies". Thanks, SP. :). I seem to be lacking your patience today…

    • wideawake wideawake

      So 126 fuel rods have been removed, loaded with enough plute to Kill millions of innocent human beings…that leaves 215,074 fuel rods to go, loaded with enough plute to Kill millions of innocent human unborn beings. ok I get that…How many pellets are packed into one rod?…. Maybe the nutters leave one hole unfilled just for Luck!

      • razzz razzz

        Plutonium is a byproduct of fissioning uranium and only used-spent fuel rods would produce plutonium over time when being inside a working reactor. Besides all the other radioactive poison byproducts produced.

        There is no plutonium in a unused fuel assembly unless it is made up of 'MOX' fuel rods to begin with where they purposefully mix plutonium with the uranium so the fuel will burn hotter (estimate 10% of the fuel would be plutonium in a MOX rod. Unit 3 had some MOX fuel assemblies in the working core and supposedly none anywhere else.

        Plutonium is consider to be a man made element.

        Fukushima Diaries reports that TEPCO didn't even bother putting the unused fuel assembly (remember an assembly is a collection of fuel rods) in a cask before they removed it. Thought they would have practiced a procedure using a cask before removing an assembly even though an undamaged unused assembly is relatively safe to handle in open air. Later on, used-spent assemblies have to be placed in a cask before removal. Hope they know what they are doing.

        For reference…
        http://www.nfi.co.jp/e/product/prod02.html

        • wideawake wideawake

          aargh sickening link… thanks…learnt one thing though.. The nuclear nutters pack approx 350 uranium (possibly mixed with plutonium) pellets into one rod.

        • dharmasyd dharmasyd

          razzz…Thank you for your good information. I am very happy to see those with some real understanding posting here. JoyB is another one, and she has been with us from the first. There are others. Forgive me for not mentioning. Tjhe posting of accurate knowledge gives credibility to this site.

  • Notice that NHK qualifies the assemblies being (or having been) removed as "unused." That means they aren't spent, so should be far, far less radioactive than even the oldest of the spent fuel assemblies. You can walk right up to a new assembly and tighten the screws by hand if need be, they do not become dangerous until they've experienced fission. These new assemblies would not have heated to melting temperatures if the pool were drained, and were probably isolated from the active core that was in the pool, possibly still in the transfer area where it would be easier to put them into water-filled casks for transfer to the common pool.

    I'd sure be interested to know whether these assemblies were 'damaged' and how hot they were when pulled out of the water. If they were actually removed rather than put right back where they were…

    • dharmasyd dharmasyd

      JoyB…And Tepco seems to be imposing a blackout on this information. Oh well! What else did we expect?

  • jec jec

    How hot? Guess we will tell if and when radiation monitors in USA show increase..or not. Also, the top of the "work" area of Reactor 4 is CLEANED OFF. Not as if done by a scoop or "jaws". Wonder if the carbon based life-forms did that in the "dark" or "foggy" times.

    One other thought..all at once TEPCO stepped up the push..FAST..Emergency tempo. The top cut off in days, no warnings, then fuel assemblies pulled out..same same. Either the international community has finally stepped in or something has been identified as being WORSE than what has been reported. Since I cant think of much WORSE than four reactors in meltdown, corium into the bedrock, and thousands/millions of people radiated– It does boggle the mind. Something kick started the process — or are those specific fuel rods–the new ones–exceptionally dangerous? MOX X 15?

    • mungo mungo

      jec, that is my opinion also….tepco never been in such a rush before….

    • Sickputer

      I thought I saw some of those grab and run motions several times. I was really looking for signs of replacement rotation (of Unit 4 workers) to indicate the stuff was really hot. Thought I saw a lineup several times on the left but it may have been traditional heavy lifting safety protocol.

    • PhilipUpNorth philipupnorth

      jec: Seems there was some talk early on about a new MOX fuel load in SFP4. Also saw a discussion of TEPCO license application for MOX to be used in Reactor4. I recall that the app was pending on 311, but that it was not approved before 311. I might be mistaken in my recollections. I have since Googled to try to find the original source for this info without success. So take this as conjecture. If anyone has original sources for this material, could you please post it? Many thanks. This is nothing new, so TEPCO has known what is in SFP4 from the beginning. I conclude that if there has been a sudden urgency in TEPCO's actions, it has another cause, like Building4 is moving and crumbling under their feet.

      I have seen a photo of SFP4 post 311 that clearly shows a load of new fuel in a rack in a corner of SFP4. The spent fuel is spaced out in the racks, but the new fuel is in adjacent rack holes, and stands out in the photo.

  • mungo mungo

    these 'inert' fuel rods were placed in the common pool 50metres from reactor4 right? so any radiated fuel could be stuck to these rods? so the common pool now has a reaction to this….looks like common pool is 'glowing' on jnncam….

  • Andres Arce Andres Arce

    What are they raising, round the third reactor ?