Nuke-newbie

Ok so I'm no Homer J. Simpson but how come a nuclear power-thingamigger needs external power as seen in fukashima? Once the generation starts, why doesn't control room and other operations power run off parasitic power?  Sure triple back up with diesel and batteries but come for a nuke plant to run out of duracell power to run cooling pumps?  Isn't that why we have a nuclear navy? Or am I missing some law of thermodynamics.

9 Replies

  • Anonymous
    Anonymous

    nuclear reactors once tripped must be cooled due to decay heat. its not something that is just turned off with a switch

  • I know they must be cooled but, like a car once the engine starts the alternator runs the electrical; how come once the reactor is at power will you not have enough juice to cool all decay and reactor related heat sinks?  There isn't enough heat out of decay to get any power? Even supplemental cooling pumps started? But the decay is hot enough to boil zinchromium in seawater or something like that. Maybe not megawatts but watching the meltdown in Japan there seems to be alot of outgassing or pressure that if taped to an emergency generator would have saved alot of headaches.  

    Again I'm no scientist but what about a decay heat power reactor in the swimming pool reactors and spent pools.  Just shooting off the hip.... Maybe a molten metel transfer for a  ~1Mw output to drive a battery bank/capacitor and control room.  Then tie into the grid for redundant redundancy

  • Anonymous
    Anonymous

    In reply to Salamnder:

    there are some plants that have steam driven pumps that do that very thimg. i  shoulden get in to the works of it. i dont know if bw reactors are equipt with them though.

  • In reply to Anonymous:

    Interesting, thank you.  Now how much plutonium is needed to generate 1.21 giggawatts? (only thing that stayed timely in that movie was Libyan terrorists), 1985 here we go!

  • Anonymous
    Anonymous

    In reply to Salamnder:

    BWR plants do use residual steam to drive a RICC turbine pump for core cooling

  • Anonymous
    Anonymous

    In reply to Anonymous:

    but the steam pumps dont work well when the piping is ripped off due to an earthquake  thats above  the design basis of a plant.

  • Anonymous
    Anonymous

    In reply to Anonymous:

    many of the us plants have many  emergency assets that can be used many of which i can nt talk bout on a public forum.

  • In reply to Anonymous:

    RCIC is Reactor Core injection coolant system they run off electric pumps. HPIC is High Pressure coolant injection system that is the steam turbine driven pump in a nuclear plant.

  • In reply to Salamnder:

    Once a reactor goes scram power production of the plant stops. Either off-site power must be utilized to run the plant including the residual heat removal system to cool the reactor to what is known as cold standby. Then continuous cooling of the system must be maintained. In the event off-site power is not available emergency diesel generators are used as back-up power to maintain cooling. No matter what once a plant is off line some form of power must be used to keep it cool. There are new battery back-up systems now being deployed, but again they only provide a certain time frame of availability. Most plants in the US do have back-up cooling systems where pumps can be directly hooked into the cooling systems to keep the reactor cool either with  fire trucks or portable diesel pumps.

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