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Japan Re-Opens Some Towns Near Fukushima
JSBiff writes "Bloomberg, among others, is reporting that the Japanese government has partially lifted the Fukushima evacuation order, allowing residents to return to five towns previously in the evacuation zone. Additionally, a key milestone has been reached in achieving a full 'cold shutdown' of the damaged reactors — the temperature of all three reactors has dropped below 100 deg. C. It's a shame these people were unable to return home for six months. For people who lived closer to the plant, they might never be allowed to return home. Now, the question is: will residents actually want to return, other than to maybe retrieve stuff they left behind?"
Having read the article, it seems the summary is completely inaccurate, as the five towns in question were not evacuated. The government is just lifting a "be prepared for evacuation" warning.
Such disasters can render areas uninhabitable for thousands of years.
The isotope responsible for almost all of the long term contamination is Cs-137, with a half life of about 30 years. So every century, the activity level drops by a factor of 10. IIRC, the most heavily contaminated area discovered (very close to the reactors) was giving a dose rate of 500 mSv/yr, so even that should be down to below background levels in 3 centuries, with most of the currently excluded area safe long before then.
Now, that's still a heck of a long time - but it's not the thousands of years you mention, and it means that large scale use of nuclear power for centuries will not result in ever-increasing amounts of land lost due to contamination from accidents.
It's worth noting for comparison that hydroelectric power is appalling for rendering large areas uninhabitable, even when it works as planned.
It's not being ignored. It's accounted for.
1) The vast majority of the region around Chernobyl will probably be safe within a few hundred years. The area immediately around Fukushima will probably be considered contaminated for 50-100 years. Hiroshima and Nagasaki were continuously inhabited, with very little to no negative effect on post-bombing residents. This is nuclear science 101. If radioactive isotopes are extremely dangerous, that means they have short half-lives, and thus are only around for hours or days. If contaminants last for thousands of years as you allude, that means they have long half-lives, and thus are not very radioactive nor dangerous enough to render the area uninhabitable.
It's the radioactive contaminants with medium half-lives which are most dangerous. Their half-lives are long for them to stick around for years/decades, but short enough that they're still dangerously radioactive. These typically have half-lives of 10-30 years, meaning their contamination will only last a few decades to a century. Very few, rare isotopes match your criteria of long half-lives but high radioactivity (it happens when the decay chain of a long half-life isotope results in a bunch of short half-life isotopes in quick succession).
2) As I outlined in the previous Fukushima topic, hydro and wind render more land area uninhabitable per MWh of energy generated than nuclear. Solar technically only renders the land shaded rather than uninhabitable, but if the panels/reflectors are installed on the ground, then it's uninhabitable. And unlike nuclear which only renders land uninhabitable when there's an accident, the renewable technologies render land uninhabitable as a consequence of their normal operation.
If, as you state, you wish to minimize the "chunks of earth removed from human habitation for many generations," nuclear is the power source which has the smallest footprint per unit of energy generated.
Such disasters can render areas uninhabitable for thousands of years.
Don't you need a mechanism by which this would occur first? Cesium 137, for example, has a half-life of around 30 years. in a thousand years, it'll have halved about 30 times which is over a billion reduction in concentration. A lot of the other stuff that made up the radiation leakage from Fukushima has half-lives in the tens of days, they already are considerably reduced.
OTOH, plutonium 239, if it was put into the environment, would have a half-life of 24,000 years. If any land around Fukushima is uninhabitable because of that isotope, then a few thousand years won't dent it much.
So what's the isotope that's going to keep Fukushima uninhabitable for thousands of years? Also how big is this uninhabitable area? Sounds like the worst affected areas are only a portion of the current exclusion zone.
My point for bringing this up is the hyperbole that surrounds the Fukushima accident and clean up. We need to cut through that and realistically figure out what happened.
It isn't the direct deaths that are the problem, it is the long term impacts to the environment that remove chunks of the earth from human habitation for many generations.
Humans do other things with land than just live on it. This sounds to me ideal for industry and, of course, more nuclear reactors. If they have another meltdown, then it won't matter as much due to the exclusion zone around the Fukushima site.
I talk to a lot of people here, and everyone seems to say the same thing. "It sucks, but what can we do?" People don't know what is and isn't safe. Different government agencies give different, and more often than not, contradictory reports. People aren't necessarily afraid of the radiation. They're afraid because they don't know what to believe. They don't evac because one report says they're safe, but then they think they should because another one says they're not.
Talking to people here about the alternatives to nuclear power, and what is feasible, I find that they all seem to agree. They'd like to see it go away, but they understand that there's only one way to get rid of it right now, and that would put Japan back in the stone age. Having said that, it seems that the market for household solar panels has increased dramatically for those who have houses and can afford it, but the majority of people here live in apartment buildings or condos. With most people living in the cities, they know there's no way they're going to get rid of nuclear power anytime soon, unless some magical new energy source appears that can produce enough power for everyone while taking up very little land.