Mitigating Fukushima's Dangers, 42 Days In

DrKnark writes "Tepco has released more information about their plan to stabilize the Fukushima reactors. They are basically facing 4 problems: ensure long term cooling of the cores; ensure cooling of the spent fuel pools; prevent release of radioactive material; and mitigate the consequences of the releases that will continue for a while."

Comments

Interesting radiation readings

[rrohbeck]

From http://theautomaticearth.blogspot.com/2011/04/april-20-2011-fukushima-review-of-ines.html:

On April 17th the same site had the following radiation levels recorded for units 1-3:

        Reactor 1
        Dry Well: 121.4 Sv/hr
        Suppression chamber: 97.5 Sv/hr

        Reactor 2
        Dry Well: N/A
        Suppression Chamber: 131 Sv/hr

        Reactor 3
        Dry Well: 253.2 Sv/hr
        Suppression Chamber: 103.9 Sv/hr
So that's going to take a while to cool off.

Re:Interesting radiation readings

[Anonymous Coward]

Um, no, 1 Sievert = 100 rem, so in 5 hours you would get 50 k rem, and a normal lifetime dose in 9 seconds.
So according to the handy and authoritative ;-) XKCD radiation chart, the emergency workers would get a guaranteed fatal dose if they stayed for 5 minutes.
<handwaving>
Assuming the Iodine has already decayed by now, I thought the next most abundant decay products are Cesium and Strontium with half-lives of 30 years, if that's true then they could work for an hour until fatal dose in about 109 years time. ( 100 Sv/hr present / 8 Sv/hr lethal = 12.5; log(12.5) / log(2) = 3.64; 3.64 * 30 years = 109 years, if I didn't make any mistakes). Then they could work for 15 minutes until a "emergency radiation worker" 100 mSv dose after waiting for a cooling-down period of 239 years (log (100 / 0.1 / 4) / log(2) * 30), amirite?
</handwaving>

If they're not that patient then they have to use robots or something. Who's going to pay to keep the plant guarded from terrorists until the year 2250 until they can decommission it safely? Copyright doesn't even last that long (yet).
I find it very suspicious that nobody's even mentioned measured levels of Strontium-90 because it stores itself in the bones of people building new bone mass (i.e. children). They only talk about measuring Iodine and Cesium but Strontium should also be more than 5% of the fission products, almost as much as the measured Iodine (3%?) and Cesium (12%?)

Re:FTFA

[Mindcontrolled]

Reasonable people are demanding that we review our use of oil for years. What's your point?

Re:Quite possibly...

[Kyusaku Natsume]

The main trouble with depleted uranium comes from its toxicity, not from its radioactivity, you can see that since as you pointed out, the half life of U238 comes in a geological timescale.

Re:Coal vs. Nuclear

[JSBiff]

But, there's one important difference - if used appropriately, every ton of Uranium has the energy equivalent of something on the order of a million tons of coal or oil. Also, don't forget about Thorium. Uranium is not the only nuclear fuel. Thorium is estimated to be at least 5 times more abundant than Uranium.

I've seen some analyses which estimate that, if we used fast breeder reactors (like the Integral Fast Reactor - search for that sometime, interesting reading) and Liquid Thorium Reactors, we have enough fuel supplies to last us at least 100,000 years. Also, both technologies solve the 'nuclear waste problem' by burning off the nuclear waste.

If we can extract Uranium cost-effectively from the ocean, we have enough Uranium to perhaps get us through a few billion years (and, over the course of a Billion years, more uranium will leach out of the earth's crust [there's all kind of uranium in the crust, but not concentrated enough for effective mining, but if it dissolves out, it might be recoverable] and into the oceans, making it an effectively renewable resource).

Nuclear power has it's challenges in terms of safety and economics. Fuel supply is not a real problem though. If you are *really* worried about a fuel supply which might run low in 100,000 years, I don't know what to tell you. I don't worry much about problems that far down the road.