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Thoughts on nuclear power and disasters [long, rant/tangenty]

by HowardVAgnew
Tags: disasters, nuclear, power, rant or tangenty
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HowardVAgnew
#1
Mar2-12, 04:20 PM
P: 17
I would describe myself as a "layperson plus" who enjoys reading on topics such as nuclear engineering, but definitely do not possess genuine physics nor engineering expertise beyond high school advanced placement courses (which were twenty years ago anyway, and much of what I learned then has undoubtedly rusted away). I do think about such things from time to time, though, and certainly last year's earthquake and tsunami that ravaged Japan and triggering the worst nuclear disaster-event to trigger since Chernobyl (the specific labelling intended to dismiss ongoing disasters from Chernobyl and earlier that I accept as ongoing disasters through today, including Chernobyl itself and, in my own back yard, the Hanford site).

I consider myself concerned quite greatly with the environment. I tend to question things a lot, even when some precepts of a topic dear to me, such as environmentalism is challenged by findings or challenges to findings.

I do believe the nuclear industry is pre-disposed to quell valid concerns over nuclear power, but I do not believe abandoning nuclear power altogether is a definite solution to work toward. Our modern era is very energy-hungry, and while the horrors of a nuclear disaster such as Chernobyl and Fukushima should never be understated, neither should the benefits and potential benefits of nuclear power.

Hydroelectric dams are, by the general not-completely-devoted-or-understanding-of-environmentalism, often I think mistakenly viewed as safe, clean energy by the public. The effects of a disaster at a dam, though, I think is more conceivable to a layperson than the effects of disaster at a nuclear reactor. Should a hydroelectric dam breach, a lot of people will likely quickly die and there will likely be a lot of significant damage downstream of the dam ... but that's it. By compare, should a nuclear reactor incur serious problems, radioactive material will contaminate land and render potentially significant swaths of land unsuitable for habitation, any productive use or even wildlife habitat for /decades/ or longer. I think my backyard example of Hanford exemplifies this: when most folk think of nuclear disaster, quick meltdown events like Three Mile Island, Chernobyl and now Fukushima I think too quickly come to mind to too many. Hanford was the birthplace of the world's very first nuclear devices. Much of what we know about the dangerous side effects of nuclear power have been learned the hard way at Hanford, and with each passing decade, new disastrous repercussions are realized. It was only a few years ago that it was realized severely toxic contamination is spreading through the water table and will likely reach the Columbia river sometime in the near future, potentially completely killing the entire Columbia river ecosystem, through cities like Portland, Oregon and the Pacific Ocean.

The United States seems to me to be much less prepared to handle a disaster like a Fukushima event; I think Katrina is very solid evidence of this. No, Katrina was not a 'nuclear' disaster but it was a significant one, and despite the huge advantage the United States had in Katrina over Japan's Fukishima -- the realization New Orleans was going to be hit days before it actually was, whereas the earthquake that triggered the tsunami was impossible to specifically forecast -- incompetence and mis-management on many levels doomed some thousand people to death by latency in and overall lacking evacuations. I think we should have emergency evacuee centers prepared throughout the country to prepare for evacuations across broad regions and transports ready to go with a few hours' notice to collect evacuees, including our mega-metroplis areas like New York City, Los Angeles, Chicago and Houston. National Guard units from every part of the U.S. are prepared with tanks and fighter jets for what has not happened on the U.S. mainland since the Civil War -- invasion by foreign militaries. Why aren't we prepared for disasters that have struck with transports like large helicopters that could have, say, plucked survivors from the top floors of the World Trade Center in New York on 9/11 or the freeway overpasses and the Superdome in New Orleans following Katrina?

Disasters at nuclear plants are just one of many potential disasters, but I think considering worst possible events, however unlikely, must be prepared for. While they are much rarer away from the West Coast, mega-earthquakes in the 7.0+ range have, historically, struck and affected the U.S. heartland and the east coast, and there don't really seem to be designed-in safeguards to prepare for these. Pan-Atlantic tsunami are, I think (granted I haven't checked) probably not much less likely than Pan-Indian Ocean tsunami; I am aware of several examples, such as the 1755 Lisbon quake, that have created significant tsunami that affected the east coast of North America, but the 'assurances' I heard given by east coast nuclear plant operators seemed to rely on such events never actually occurring.

I think there are a lot of potential benefits to nuclear power, but however rare a nuclear disaster might seem, the immense consequences of one I feel justify extreme restrictions, regulations and preparations for catastrophic failure in each and every nuclear plant built or operated.

It does lead me to a hypothetical design consideration ... suppose Fukushima or Chernobyl had been built underground, such that if all else failed, they could be buried and sealed below the level of the water table so that, in the event of a meltdown, the disaster could be contained to the facility itself. Is there any un-overcomable reason this would be too impractical or simply not work?
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etudiant
#2
Mar2-12, 04:42 PM
PF Gold
P: 866
My guess is that the challenge would center around the cooling, as usual.
The plant needs to dump two thirds of its energy as waste heat, so a river has to flow through the plant somehow. If that river needs to be pumped back up a few thousand feet, it really hurts the plant efficiencies. If the flow stops, the coolant boils away, creating world's biggest kettle, steaming back to the surface through the coolant ducts.
It would still be a mess, imho, just an even harder one to deal with.
HowardVAgnew
#3
Mar2-12, 04:51 PM
P: 17
The inability to power pumps to maintain cooling did not seem, in the case of Fukushima, to relate to the fact the diesel generators to power those pumps were above ground. In hindsight, they may have been better off if the generators were higher off the ground, but that's no guarantee either -- if the generators were higher up, the initial quake itself could have knocked them down and destroyed them (or a typhoon or powerful storm).

I don't really understand why the mess would be harder to dealt with, though ... with an above ground reactor, it seems to me that it is harder to seal/bury it to prevent radioactive material reaching the atmosphere and creating a wider disaster whereas one that was subterranean would have a beneficial bottleneck more readily plugged. Not a perfect solution, I think, but it seems to me to provide a more solid "last resort" option than is possible with above-ground reactors.

Rive
#4
Mar2-12, 04:58 PM
P: 357
Thoughts on nuclear power and disasters [long, rant/tangenty]

Reactors cannot be just stopped: after shutdown they are still producing lot of heat.

If you plug that bottleneck then what you created is a (dirty) bomb. The temperature and pressure will rise and...

Ps.: the other point is, that to be sure that nothing is leaking and everything is under control you have to be able to reach and check the whole site. It's a bit harder underground, especially with the bottleneck plugged.

In Fukushima it's also hard, but at least they have choices other than keep it plugged and praying.
HowardVAgnew
#5
Mar2-12, 05:04 PM
P: 17
It is my understanding that nuclear bomb detonation tests underground successfully contained most radioactive contamination. As the core melts from loss of control, wouldn't it drip down and eat through the floor, falling further underground? You would have to, of course, plug everything off -- cooling water inlet, the outlet for hot water, every air duct and vent, etc., but wouldn't the result be a much lower risk of contamination outside of the reactor with sufficient design and engineering?
Rive
#6
Mar2-12, 05:14 PM
P: 357
Underground nuclear tests did not really contained the released material. The remnants of the bomb and the load is just mixed with the soil, and with the site well chosen it's migration is conveniently slow.

The amount of such places which is safe that way and will not needed in the next few millenia is limited, so it's not a real option.

Another point is, that a nuke contains only a limited amount of fissile material (few dozen kilograms, as I know) which is easily cooled down after the nuke gone off: while a nuclear reactor contains several tonnes of stuff which still 'going on' for years if not cooled properly.
nikkkom
#7
Mar3-12, 05:54 AM
P: 611
Quote Quote by HowardVAgnew View Post
It does lead me to a hypothetical design consideration ... suppose Fukushima or Chernobyl had been built underground, such that if all else failed, they could be buried and sealed below the level of the water table so that, in the event of a meltdown, the disaster could be contained to the facility itself. Is there any un-overcomable reason this would be too impractical or simply not work?
I think you partially have a point: when looking at reactor building schematics, it strikes me why reactors are not at the bottom of the basement. I imagine a last ditch cooling attempt in a disaster would be to flood entire reactor compartment with oodles of water - but for that, this compartment needs to look like a pit at the very lowest levels of the plant, completely watertight from below and sides. Instead, I see many pipes, penetrations, and rooms adjacent or below the reactor.

However, your proposal to seal reactor is risky, it makes sense only if the alternative is a massive release from a exposed core (Chernobyl). It's much better to try to retain active thermal control - i.e. be able to monitor and cool it.

I think the best what can happen post Fukushima is if all new reactors will be required to have a fully passive emergency cooling system, and operators will be required to train personnel how to use it. Perhaps even to the point when it is activated after every planned shutdown.


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