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Japan

Third Blast At Japan's Fukushima Nuclear Plant 691

Posted by CmdrTaco
from the good-luck-over-there-guys dept.
iamrmani was one of several people reporting updates on the Fukushima Nuclear plant that has been struggling following last Friday's disaster. A third explosion (Japanese) has been reported, along with other earlier information. MSNBC has a story about similiar reactors in the US. We also ran into a story which predicts that there won't be significant radiation. But already Japan is facing rolling blackouts, electricity rationing, evacuating the area around the plant, and thousands dead already.
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Third Blast At Japan's Fukushima Nuclear Plant

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  • Re:Journalism (Score:5, Interesting)

    by vlm (69642) on Monday March 14, 2011 @10:24AM (#35478986)

    Sorry to dampen you optimism, but these reactors are going to be totally useless after this. The reactor vessel will almost certainly be beyond repair and it is central to the entire plant. Economically it would be easier to just build a newer design of plant.

    They were planning to build two new reactors onsite, # 7 and #8. They'll probably end up with new ABWRs to replace the old clunkers. Note that a single ABWR outputs as much power as three BWR-3s or two BWR-4s so yanking three 40 year old dinosaurs does not necessarily mean they need to build three new ABWRs to take their place... My guess is they'll get one.

    I'm hardly on their board of directors but most likely instead of adding 2 new ABWRs they'll probably simultaneously build the currently planned two, decon the old units 1 / 2 / 3 and build a nice new ABWR on top of the old site of 1 / 2 / 3.

    Its is possible, that after this excitement, they'll yank all the old BWR-4s and the one decent BWR-5 and replace the whole works with ESBWRs. A pity GE gave up on the SBWR... That design would have been pretty much inherently safe in this situation. Of course I'm a little fuzzy on dates, I think the SBWR design was done a decade or two after the BWR-3 and BWR-4 were built at Fukushima and I don't remember why GE gave up on the SBWR design anyway (maybe the navy or other govt considered it too "sensitive", despite the navy's fondness for PWRs?)

    http://en.wikipedia.org/wiki/Fukushima_I_nuclear_accidents#Reactors [wikipedia.org]

  • Re:Journalism (Score:2, Interesting)

    by Ol Biscuitbarrel (1859702) on Monday March 14, 2011 @10:38AM (#35479216)

    As it happens Unit 1 was scheduled to be shutdown and decommissioned in March, 2011.

  • by vlm (69642) on Monday March 14, 2011 @10:43AM (#35479268)

    Those reactors are already destroyed. They will never be operational gain (it says that in the article I linked to).

    Careful, reactors 1 / 2 / 3 were online hot and currently self destructing due to decay heat. On the other hand, 4 / 5 / 6 were off for maintenance and as far as I know are cold shutdown. They will be restarted in the future assuming they didn't take too much tsunami damage and/or explosion damage from 1/2/3 popping. You will not be too surprised to learn that 1 / 2 / 3 are the oldest reactors, some 40 year old clunkers. The newer design 4 and 5 are not too bad and 6 is actually pretty decent. And they're planning on building some new ABWRs 7 and 8 onsite. One new ABWR generates almost as much power as 1, 2, and 3 put together.

    So the idea is to minimize contamination and damage to reactors 4 / 5 / 6. Remember only one of Chernobyls reactors melted down, the other continued generating power for a decade or something like that.

  • by MrNemesis (587188) on Monday March 14, 2011 @01:21PM (#35481530) Homepage Journal

    Chernobyl's RBMK reactors were too big to contain without it costing a ridiculous amount, so the building was the secondary containment structure - and it fell apart like tissue paper, as expected

    IIRC it's not that the RBMK reactors themselves were too big, but that they were designed to have their fuel replaced whilst the reactor was running and keeping all the loading gear inside containment was space prohibitive. There's an awesome cutaway model here http://neutron.kth.se/gallery/power_reactors/Ignalina_model.JPG [neutron.kth.se] that shows the colossal crane/gantry above the core, along with what basically amounts to a shed roof covering the reactor core. Not pictured is the cooling pond, which sits parallel to the core (and takes up more space) that the spent fuel rods are dropped into.

    Fitting all that folderol inside decent containment would be very expensive, because you now need at least twice the height and width of the reactor to fit everything in. So why bother? Allowing refuelling whilst the reactor is running meant a) you wouldn't need to close the reactor down to refuel it and b) you could make lots of weapons-grade plutonium very quickly. Weapons grade stuff requires very short fuel runs on a low burnup (exactly what you don't want in a reactor for power generation), whereas extracting P239 from all the other plutonium isotopes in "regular" nuclear wastes is exceptionally difficult. Since these reactors are expensive, lots of countries decided to cheap out and build dual purposed reactors which, after enough warheads had been made, could then be converted to civilian fuel loads. Hence you had a bunch of suboptimal design decisions taking place, such as the lack of containment on RBMK and other reactors. Yay for the cold war.

    Not meant as a nitpick BTW, just thought people might find it interesting.

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