Nuclear Crisis: 'Chain Reaction Could Restart'

Source: New Scientist

The situation at Japan's Fukushima Daiichi nuclear power plant has become extremely unnerving. The Tokyo Electric Power Company has now admitted that the spent fuel rods could go critical - that is, a nuclear chain reaction could restart.

We have known since yesterday that the reactors themselves were coming under control, and that the biggest threat came from the spent fuel ponds, where the water level has fallen and temperatures have risen. That could lead to the stored fuel rods breaking open, releasing their radioactive contents.



This is a real surprise. These ponds are a standard feature of nuclear reactors, and are typically designed to ensure that nuclear reactions cannot restart in the fuel rods. Among other things, the rods should be widely spaced in the pond.


more: http://www.newscientist.com/blogs/shortsharpscience/2011/03/nuclear-crisis-radioactive-fue.html

Currently it is 4:43 AM on Thursday the 17th of March in Japan. Just to help those here to keep things straight in their minds.

What I'm was trying to say was Kyodo News is always in JST. So if you thought you read/heard this yesterday, you may well have. Hope this helps.

my mind will never be straight again.

j/k Thanks - various time zones around the world, still haven't adjusted all the clocks in this house.

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Just keep in mind they're more than a half a day ahead of us here in the US. It varies depending on what part of the US you're in. It's early morning on Thursday there now, and mid afternoon Wednesday here in my time zone. I'm CST.

IIRC there are among the fission products several neutron absorbers. A fuel is "spent" when the rate of those absorbers becomes troublesome. There is still plenty of fission material left in the rods but it becomes more difficult to maintain the chain reaction. That is when you reprocess the fuel to clear out those isotopes.

"Spent fuel" is only about 5% used however it now has too many isostopes which prevent fission. An analogy would be like water in gasoline. After about 3 years the fuel is replaced with new fuel.

If they could design a reactor that processed or filtered the fission products one fuel load could last the life of the plant. Build a plant load it, shut it down in 60 years and decommission it.

Why it isn't standard procedure to douse spent rods with Boric acid?

Why use pools?

...blocks practically all radiation and cools the rods.

I have stood over such a pool looking down on the spent rods in the clear water, without the water I would have been fried by the radiation.

fail to maintain the level of water. Too bad there is not a way to engineer a kill switch with boric acid but I am sure that if it was that simple - it would of been done.

Reactor #4 has evaporated all the water. It would have ecaporated any boron too.

...having no moderator is the surest way of all to kill the chain reaction.

Quite unlike the Web... ;-)

Recriticality



Potentially an uncontrolled nuclear reaction can occur in "cooled" fuel rods in a boiling-water reactor during saturation with coolant

You need high enriched uranium or very pure plutonium to actually detonate a nuclear bomb. No matter what you do to the spent reactorfuel, regardless of temperature or quantity, it will not detonate as a nuclear bomb.

That is reactor 3...or is it 4?

I guess, in any event, it would not be an explosion on the scale of a nuclear bomb.....but if plutonium was released in an explosion it would be very very bad, nonetheless. I am unsure of the science behind it all.

MOX contains plutonium and plutonium is both radioactive and toxic. But there is so much crap in spent fuel that Plutonium really only makes things marginally worse.

Oh wait... sorry! I forgot that DU was now the alarmist fantasy BBS. Proceed.

all you get is silence.

And you can find some answers in this thread.

You`re welcome.

Please read the link in the OP and you`ll get a clue.

With your post you didn`t add anything helpful to the topic.

It isn't alarmist bullshit to simply share a quote from the fucking company dealing with the problem.:eyes:

The sun, for example, will not explode tomorrow. Good news right? For you perhaps, but for me, not so much.

Sadly, my unfailing ability to reject alarmist worst-case bullshit has robbed me of any chance at a career in journalism. But on the bright side, no comets will impact the earth within the next few decades, so I have that going for me.

Again, this OP is just the statements made by the company dealing with the problem. It is by no means alarmist worst case bullshit. If anything, they have been and will likely continue to downplay the risks.

:shrug:

As far as what is going on in Japan, this is all you need to KNOW:

There is no super conspiracy going on. The people getting the information first hand are being careful not to downplay the potential issues, but they have also been very clear that they anticipate getting things under control. They have released all the numbers that matter to the public, and those numbers are not bad at all. They are, in fact, absolutely un-alarming. Which is good, because while no one else may be in serious danger at this time, they ARE.

If you want to imagine possible but unlikely scenarios that you believe will advance your agenda be my guest. But don't expect everyone else to treat it seriously.

At that reactor.

appeared out of nowhere and started laughing at all the scared people...calling them idiots and fools. So, you see, we have a bunch of Foxnews pundits eating crow every other day over their uncontrolled mania. Guess you must have missed all that though... :eyes:

congrats... I guess this topic and DUers are getting under your skin.

Then count me out. I am not into the whole hysterical fear thing.

Strange. If I didn't care about something I would just ignore it, maybe even hide thread.

BTW, welcome to DU, enjoy your stay.

lol

turn homicidal and plow into each other.

There is a chance, sure, but closer to the odds of the Earth leaving orbit because of the force of the earthquake, instead of the likelihood that the greeen stoplight I am looking at is going to turn yellow in a few seconds.

I liked this from the article:

"In the longer term, questions will be asked about how the ponds wound up in this condition, when it should have been completely avoidable."

How the ponds wound up in this condition? Did the author in the link have the channel on that forgot to mention the 9.0 earthquake
and the resulting tsunami, I wonder? Or perhaps there is documented evidence that he told people before these were ever built that he foresaw a natural disaster worse than any that had ever occurred in the area, that would slam the reactors in such a way? Going forward we should look at these designs and learn from it, but to say that engineering can always overcome accouting and resources to prevent any disaster is an unrealistic outlook.

This is serious, nobody disputes that, and we still don't know how bad it will be, nobody disputes that. But throwing out very unlikely scenarios as if they are anything but a remote possibility is nothing but fearmongering. There is urgent work that needs to be done to prevent the more likely damage, not to mention feeding and providing shelter for a few million people who have none, a far different problem. The author's writing is not that helpful.

Read the fucking article.
The possibility of restarting the chain reaction in the spent fuel ponds was trotted out by TEPCO. Don´t blame this on DU.
The mere possibility of problems with the ponds two days ago was belittled here by your fellow pro-nukes brigade.
Funny campfire analogies were ventilated.

Everything happening today was only a "remote possibility" yesterday.

As if you were concerned with the urgent work that needs to be done. Go ahead make yourself useful.
The author was writing about just what the headline says. Don't blame him not to write about what you'd like to read.

in your crusade fervor you might have read that. I never belittled the problem - but I am not making things up or running around in a tizzy either.

The article doesn't add anything, and neither does responding to argument based on superstition. Bye.

they are here for a reason and it isn't to engage in a honest discussion.