Tepco: ‘Burnt area’ on Spent Fuel Pool No. 4 secondary cooling pump (PHOTOS)

Published: June 5th, 2012 at 11:56 am ET
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Unit 4 Spent Fuel Pool Alternative Cooling System Secondary System Circulation Pump (A) Situation of the Burnt Area Near the Motor Terminal Housing
Tepco
June 5, 2012

Published: June 5th, 2012 at 11:56 am ET
By
Email Article Email Article
48 comments

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48 comments to Tepco: ‘Burnt area’ on Spent Fuel Pool No. 4 secondary cooling pump (PHOTOS)

  • Tumrgrwer Tumrgrwer

    That is a bad electrical connection. Who ever put the wire nuts on with or without tape did a poor job. I have seen this many times with pumps, switches, welding equipment. Normally happens when connections get wet if not properly insulated. Re wire, turn on…fixed pump.


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  • norbu norbu

    the ground wire hooks to the other ground wire, hot to hot, or they put 440 to it kaboom…


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  • Tumrgrwer Tumrgrwer

    Normally, I think Japan uses 220/240 Volts. If they put 440 to a 220 line there would be a circuit failure. This is from either a poor connection or maybe the pump impeller is impeded/stopped somehow, causing an overload conditons.


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  • norbu norbu

    maybe they had a person who normally works in a office hook it up?


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  • norbu norbu

    17 years in heating and air conditioning have seen this before.


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  • Dogleg Dogleg

    It is a 3 phase 480 volt motor. From this pic I cannot see that there was improper wiring. Looks to me like heat caused the tape to melt off the wire connection and short out against the cover causing the hole in it.


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  • Tumrgrwer Tumrgrwer

    Ok, if it is a 3 phase 480 volt motor then why are they using such a small gauge wire. Looks fishy to me. I blew it up 400% and can see the wires cooked/melted to the bottom case and burnt threw. It's a terrible job, done in a rush by an untrained or improperly instructed electrician.


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  • Tumrgrwer Tumrgrwer

    This is exactly the kind of crap that I have been worring about. Some under educated, untrained employee installing something like this and found too late. Look real close and you can see the ground wire is the proper size while the load and common are too small.


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    • aigeezer aigeezer

      You've got a point Tumrgrwer. Also, I'd guess the installer was all suited up, gloved, looking through a mask and glancing at a dosimeter.

      I haven't seen any data on how long the thing worked before it blew. Perhaps that's relevant also – I don't know.

      Anyway, if "oopsies" happen in these plants at the best of times (and they do), then under the current crisis conditions there will be plenty more… and the world can't afford them.


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  • norbu norbu

    it should have 2 hot leads. 3 phase


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  • robertsgt40

    "Made in Japan" comes to mind. Maybe with a little corner cutting with help from GE


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  • Tumrgrwer Tumrgrwer

    I also found this; The voltage in Japan is 100 Volt, which is different from North America (120V), Central Europe (220V) and most other regions of the world. Japanese electrical plugs have two, non-polarized pins, as shown above. They fit into North American outlets.

    Japanese power outlets are identical to ungrounded (2-pin) North American outlets. While most Japanese outlets these days are polarized (one slot is slightly wider than the other), it is possible to encounter non-polarized outlets in some places.

    Some North American equipment will work fine in Japan without adapter and vice versa, however, some sensitive equipment may not work properly or even get damaged. If you intend to purchase electronic appliances in Japan for use outside of Japan, you are advised to look for equipment specifically made for oversea tourists.

    The frequency of electric current is 50 Hertz in Eastern Japan (including Tokyo, Yokohama, Tohoku, Hokkaido) and 60 Hertz in Western Japan (including Nagoya, Osaka, Kyoto, Hiroshima, Shikoku, Kyushu), however this frequency difference affects only sensitive equipment.


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  • norbu norbu

    "GE we bring big flames to light"


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  • Dogleg Dogleg

    The motor feeds are larger gauge wire, you can see them coming out of the conduit. The melted wires you are talking about are motor leads and are typically smaller gauge. Still dont see any problems with installation. I have 20 years in the International Brotherhood of Electrical Workers local 291 and have wired a few motors in that time. I really wish I could find something wrong with their work, but I just dont see it.


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  • norbu norbu

    nice union brother, local 104 sheet metal workers S.F.


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  • Tumrgrwer Tumrgrwer

    Japan 50/60 Hz
    Single phase: 100/200 V, Three phase: 200 V
    United States
    60 Hz Single phase: 115/230 V, Three phase: 230 V


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    • Dogleg Dogleg

      Yes, Japan probably uses 50hz (like Europe) which would lower their voltage values.


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      • Tumrgrwer Tumrgrwer

        Don't ask me why but the Japanese use both, 50/60hz. The country is divided that way also.


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      • fireguyjeff fireguyjeff

        Dogleg:
        Do educate me.
        How does the frequency relate to the voltage??
        How would 50 Hz (vs 60 Hz) lower the voltage?


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        • richard richard

          It doesn't. It's not a factor for voltage.


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          • fireguyjeff fireguyjeff

            richard:
            Well, I was trying to not start a ruckus.

            I will confess that I am fully aware that the freq has nothing to do with the voltage level.

            I was just hoping for some clarification, like maybe there was a typo or something.


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            • richard richard

              @fire, I hear you, no rukus intended ;) I had only just woken up, didn't want to get into Ohm's law at the time.

              E = I * R

              Where E is voltage, I is amperage and R is resistance.

              So, you will require higher voltage if either more amps are required (more juice) or more resistance is affected, ie, trying to push up and over a larger hill.

              A little more, now I'm here.

              P = E * I

              Where P = power (watts) So 110 volts at 10 amp equals roughly 1kilowatt.


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        • Dogleg Dogleg

          Oh ya, my bad. Had a stupid moment there. Sorry


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          • richard richard

            i mean no accusing by making the correction. i know i make mistakes in sleepy moments too (wakeful for that matter). i think that when i see something askew anywhere on the web it's 'healthy' to try to correct. trying not to be a smart*e ;)


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            • Dogleg Dogleg

              It is our duty to question when we feel information may be incorrect. I take no offence and am glad you guys pointed it out. By the way Richard, did you know your avatar is female? Touche. LOL


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  • norbu norbu

    Slow but steady. How about you?


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  • norbu norbu

    I get more side work than anything.


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  • Dogleg Dogleg

    There is a lot of construction going on here, but its all gone rat. I just spent 10 wks in ND. Doing side work now myself.


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  • norbu norbu

    yep, quality is going down the tube


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  • razzz razzz

    That's what I call a fused link. Just wire it up so the engine turns until the connections burn through.

    I'm sure(?) the circuit breaker tripped but the residual heat melted the cover plate.


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  • BreadAndButter BreadAndButter

    So cool. We have experts for literally everything on this board.

    I love this site.


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  • patb2009

    i'd bet given the high humidity, numerous leaks and just general extreme conditions, the connection got shorted out.

    now the issue is the motor shot, or is it fixable? Changing out a big pmp like that in a radiation environment has to suck.

    not that stripping a foot of wire is any fun either.


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  • jedi jedi

    Add ice , just fix-it , take a week off ? 1000 men working 24/7
    no hoildays .sorry i;m getting mad here…


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  • RememberThis RememberThis

    I wonder if neutron embrittlement might have played in the failure?

    Note all the dust crammed in the air intake….


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  • Pump Master

    This is a 3 phase pump motor, this pump motor has been single phased! period! 1Phase dropped out, the other 2 phases overloaded.

    One phase of power supply to motor failed, the other two phases tried to do the work of all three phases, hence unbalanced power supply.

    Look two groups of wires burnt, one single group wires insulation still intact.

    Enlarge picture of opened electrical box and look closely.


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  • Dogleg Dogleg

    1 phase droped out when it shorted out against the cover, yes?


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  • Sirius

    The problem, for me, is shown on plain sight.

    When you see how dusty that thing is (and there's probably no safety system in case of overheating), no wonder it burned.


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