Scrapping the Fukushima reactors

Slightly odd:

Japanese officials have conceded that the battle to salvage four crippled reactors at the Fukushima Daiichi power plant has been lost.

The plant\’s operator, Tokyo Electric Power [Tepco], said the reactors would be scrapped,

Hasn\’t everyone known that since they started using sea water in the reactors?

10 comments on “Scrapping the Fukushima reactors

  1. Not to mention the buildings surrounding them are all blown to shit. With god knows what other damage to control systems etc. Who is going to completely recommission a 40 year reactor, re-test every sensor and valve? Scrap them and build new ones is the only likely answer.

    And yes, flooding with seawater had to be a last resort, with the knowledge that they were kissing the asset goodbye. Good for them.

  2. “Now bake your reactor for 5 days at 400C from the inside” ….

    yes, these reactors are as Monty Python’s parrot, they are ex-reactors that have ceased to be. They are no more. They have curled up their tooties and shuffled…”

    I am not even sure that the pressure vessel could be reused – its been annealed for a week, and will probably be soft and weaker than it used to be.

  3. Yes – one of the main concerns when I was tangentially involved in running a UK PWR was the chlorine concentration in the primary coolant. It doesn’t play well with stainless steel.

  4. Evil, I’ve never had the opportunity to deal with nukes, but I remember speccing some pressure sensors for a 120m deep groundwater recharge well. Turns out you can get them in titanium, which is just as well given the huge amounts of calcium carbonate and (being bayside) chlorides in the water. Stainless wouldn’t have lasted long at all I suspect. I know if you got the untreated groundwater on you it raised welts and your clothes dissolved in the wash. Ph was something like 11.

    On the energy front, Geodynamics, a company here in Australia trying out ‘deep hot dry rocks’ geothermal power had a couple of their test wells collapse when the stainless steel they were using to case them failed catastrophically from chemical action. Had to fill them with concrete. No word yet on whether they’ll try to raise enough funding to sink one with a titanium casing :)

  5. Stainless and halides – bad news. Perhaps reactor #4 might have been salvageable, since I’m not sure it got the brine treatment, but 1, 2, & 3 had probably been viewed as doomed even before they ushered the sea water in.

  6. diogenes

    Yes.

    General point – true. All reactors cooled with sea water were automatically written off immediately.

  7. Does anyone know why they did it then? I mean, the containment vessels were supposed to withstand a complete meltdown anyway weren’t they? Once the chain reaction was shut down why not just let them melt from residual heat and puddle on the bottom of the containment? Is it easier to do the subsequent cleanup if the fuel rods are intact or what? Or is the security of the containment vessel something you hope is there but you don’t rely on if you can help it?

    Honest question. It’s not my field and I’m certainly not criticising the actions of the operators.

  8. Is it easier to do the subsequent cleanup if the fuel rods are intact or what?

    Much, much easier. And safer.

    Or is the security of the containment vessel something you hope is there but you don’t rely on if you can help it?

    “Defence in depth” – why waste a barrier (or, actually, 2 – the fuel pellets and the rod cladding). I suspect they knew the reactors were toast (age, the potential earthquake damage, etc) anyway.

    I’d disagree with the “hope is there” part of your query, though – they know it was designed and built that way and have no indications that there has been a sufficient failure to compromise that.

  9. Fair enough. I expected as much, but I wondered why if the reactors were screwed anyway they were going to so much trouble. But that makes sense. I just don’t know enough to be sure and wanted to check my instincts.

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