Floating nuclear plants could ride out tsunamis

Apr 16, 2014 by David L. Chandler
This illustration shows a possible configuration of a floating offshore nuclear plant, based on design work by Jacopo Buongiorno and others at MIT's Department of Nuclear Science and Engineering. Like offshore oil drilling platforms, the structure would include living quarters and a helipad for transportation to the site. Credit: Jake Jurewicz/MIT-NSE

When an earthquake and tsunami struck the Fukushima Daiichi nuclear plant complex in 2011, neither the quake nor the inundation caused the ensuing contamination. Rather, it was the aftereffects—specifically, the lack of cooling for the reactor cores, due to a shutdown of all power at the station—that caused most of the harm.

A new design for nuclear built on floating platforms, modeled after those used for , could help avoid such consequences in the future. Such floating plants would be designed to be automatically cooled by the surrounding seawater in a worst-case scenario, which would indefinitely prevent any melting of fuel rods, or escape of radioactive material.

The concept is being presented this week at the Small Modular Reactors Symposium, hosted by the American Society of Mechanical Engineers, by MIT professors Jacopo Buongiorno, Michael Golay, and Neil Todreas, along with others from MIT, the University of Wisconsin, and Chicago Bridge and Iron, a major nuclear plant and offshore platform construction company.

Such plants, Buongiorno explains, could be built in a shipyard, then towed to their destinations five to seven miles offshore, where they would be moored to the seafloor and connected to land by an underwater electric transmission line. The concept takes advantage of two mature technologies: light-water nuclear reactors and offshore oil and gas drilling platforms. Using established designs minimizes technological risks, says Buongiorno, an associate professor of and engineering (NSE) at MIT.

Although the concept of a floating is not unique—Russia is in the process of building one now, on a barge moored at the shore—none have been located far enough offshore to be able to ride out a tsunami, Buongiorno says. For this new design, he says, "the biggest selling point is the enhanced safety."

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A floating platform several miles offshore, moored in about 100 meters of water, would be unaffected by the motions of a tsunami; earthquakes would have no direct effect at all. Meanwhile, the biggest issue that faces most nuclear plants under emergency conditions—overheating and potential meltdown, as happened at Fukushima, Chernobyl, and Three Mile Island—would be virtually impossible at sea, Buongiorno says: "It's very close to the ocean, which is essentially an infinite heat sink, so it's possible to do cooling passively, with no intervention. The reactor containment itself is essentially underwater."

Buongiorno lists several other advantages. For one thing, it is increasingly difficult and expensive to find suitable sites for new nuclear plants: They usually need to be next to an ocean, lake, or river to provide cooling water, but shorefront properties are highly desirable. By contrast, sites offshore, but out of sight of land, could be located adjacent to the population centers they would serve. "The ocean is inexpensive real estate," Buongiorno says.

In addition, at the end of a plant's lifetime, "decommissioning" could be accomplished by simply towing it away to a central facility, as is done now for the Navy's carrier and submarine reactors. That would rapidly restore the site to pristine conditions.

This design could also help to address practical construction issues that have tended to make new nuclear plants uneconomical: Shipyard construction allows for better standardization, and the all-steel design eliminates the use of concrete, which Buongiorno says is often responsible for construction delays and cost overruns.

There are no particular limits to the size of such plants, he says: They could be anywhere from small, 50-megawatt plants to 1,000-megawatt plants matching today's largest facilities. "It's a flexible concept," Buongiorno says.

Floating nuclear plants could ride out tsunamis
Cutaway view of the proposed plant shows that the reactor vessel itself is located deep underwater, with its containment vessel surrounded by a compartment flooded with seawater, allowing for passive cooling even in the event of an accident. Credit: Jake Jurewicz/MIT-NSE

Most operations would be similar to those of onshore plants, and the plant would be designed to meet all regulatory security requirements for terrestrial plants. "Project work has confirmed the feasibility of achieving this goal, including satisfaction of the extra concern of protection against underwater attack," says Todreas, the KEPCO Professor of Nuclear Science and Engineering and Mechanical Engineering.

Buongiorno sees a market for such plants in Asia, which has a combination of high tsunami risks and a rapidly growing need for new power sources. "It would make a lot of sense for Japan," he says, as well as places such as Indonesia, Chile, and Africa.

This is a "very attractive and promising proposal," says Toru Obara, a professor at the Research Laboratory for Nuclear Reactors at the Tokyo Institute of Technology who was not involved in this research. "I think this is technically very feasible. ... Of course, further study is needed to realize the concept, but the authors have the answers to each question and the answers are realistic."

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Scottingham
4.5 / 5 (2) Apr 16, 2014
Awesome! Combine this with the 'sea water to jet fuel' technology and oil rigs will seem quaint.

Also, another key factor here would have to be a design that doesn't require refueling every two years. Subs/aircraft carriers are currently good for 30, as is the Toshiba 4s.
cantdrive85
1.8 / 5 (5) Apr 16, 2014
Whydening Gyre
5 / 5 (3) Apr 16, 2014
This concept really has merit.
ryggesogn2
1.5 / 5 (8) Apr 16, 2014
But the anti-nuke watermelons will tie up any licensing for 50 years, even though navies have floating, and submersible nuclear plants
antialias_physorg
3.6 / 5 (9) Apr 16, 2014
But the anti-nuke watermelons will tie up any licensing for 50 years, even though navies have floating, and submersible nuclear plants

Yep, and a couple of those have altready sunk, and Russia (and probably soon anyone else who has them) are scrapping their old ones by merely dumping them somewhere.

If soething goes wrong on one of those platforms then guess what happens: the core gets dumped into the ocean.

Now if you're already been perking up your ears about the Fukushima radiation washing up on US shores and poisoning your food think about this: that was just the runoff from the cooling water. Think about how nifty that poisoning will be when a couple of these powerplants sink (or have to dump). And there is NO way to retreive something like this once it hits the ocean. None at all.

It's a stupid idea without a plan B.
Caliban
2.3 / 5 (3) Apr 16, 2014
This concept really has merit.


Only if one persists in viewing antiquated, inherently dangerous technology as viable.

The money needs to be spent on inherently safe, scalable, environmentally benign energy production development.
pandora4real
not rated yet Apr 16, 2014
This one is a strong competitor with the Russian nuclear powered train for being the best example of "interesting technical ideas that could never in a million years see the light of day" do to all manner of PR considerations.
Lex Talonis
3.7 / 5 (3) Apr 17, 2014
LOL - what bullshit.....

"When an earthquake and tsunami struck the Fukushima Daiichi nuclear plant complex in 2011, neither the quake nor the inundation caused the ensuing contamination. Rather, it was the aftereffects—specifically, the lack of cooling for the reactor cores, due to a shutdown of all power at the station—that caused most of the harm."

IF it wasn't a nuclear power plant, sitting RIGHT ONE THE EDGE of the ocean, in one of the most EARTH QUAKE prone countries in the WORLD, then there would not have been ANY FUCKING REACTOR to go tits up when the tsunami wiped out the area......

The Japs ought to be sticking HUGE wind generators on all the unfarmable craggy mountain tops, and along the coast lines that get the prevailing winds....

Big tsunami? Much better to lose some wind turbines that watch the kids play at night, with their glow in the dark fish fingers...

The American Nuclear Industry - if they build more reactors, the sea food will only glow brighter.
hangman04
5 / 5 (2) Apr 17, 2014
or solar platforms on water ? :/
Eikka
4 / 5 (4) Apr 17, 2014
If soething goes wrong on one of those platforms then guess what happens: the core gets dumped into the ocean.


They wouldn't really just drop the core out if "something" goes wrong.

Do you know how nuclear submarines and ships handle this problem?

They have smaller cores that have low enough power density to be self-containing during meltdown. That was one of the design parameters for the US nuclear sub fleet.

The problem with terrestrial nuclear power is that the lisencing and zoning and construction of the facility is so expensive, and deliberately made to be so, that it only becomes profitable by building extremely powerful units which have no passive safety due to their size.

A cheap standardized modular reactor could be made with complete passive safety, but you have nowhere to put it on land beacuse it would be too small to be profitable.

Eikka
4 / 5 (4) Apr 17, 2014
Now if you're already been perking up your ears about the Fukushima radiation washing up on US shores and poisoning your food think about this


"Radiation" isn't water soluble. You're just using scary words for effect.

The Soviets had experience in dumping nuclear waste and broken reactors into the ocean:

http://en.wikiped...ve_waste

It is of course illegal these days, but the data shows that the waste doesn't tend to move about. After all, most of the nuclear materials, including the fuel, is ceramic and not soluble in seawater, and it gets covered in sediment.

When it comes to floating nuclear powerplants, sinking of a reactor would be a disaster, but not nearly as much of a disaster as you'd like to think unless you do something stupid like blow it up to bits and set it on fire first. The impact of a serious accident would be far less than it would be on land.
antialias_physorg
3.3 / 5 (7) Apr 17, 2014
"Radiation" isn't water soluble.

What kind ofd a BS statement is that?
Of course do radioactzie isotopes get carried around in water.

They wouldn't really just drop the core out if "something" goes wrong.

So what exactly would they do if the thing sinks or if it has a metdown? Magically spirit it away to some safe lala-land?
The reason the stuff in Fukushima isn't melting through the floors IS that it IS melting through the floors...but the Earth has rather a lot more 'floor' than a ship.

If you want to dump this in your personal water reservoir because the stuff "doesn't move around": fine. Volunteer it as a nuclear waste disposal site.

The rest of us would rather not have that gunk in our food chain.
Eikka
4 / 5 (4) Apr 17, 2014
What kind ofd a BS statement is that?
Of course do radioactzie isotopes get carried around in water.


You were talking about "radiation" washing ashore, not radionuclides. That was just plain scare tactics tailored for people who don't understand radioactivity.

"Of course" - if they happen to be water soluble. Otherwise they precipitate and sediment out of the water and drop to the ocean floor.

So what exactly would they do if the thing sinks or if it has a metdown? Magically spirit it away to some safe lala-land?


If it's a properly designed and sized reactor, it should be self containing to the point that they can wait for it to cool down and then lift it out of the sunken platform, or if the platform is still floating, tow it away to be properly dismantled.

Again, submarine class reactors can have a meltdown and nothing comes out.

The reason the stuff in Fukushima...


Fukushima was a reactor too large; see above about passive safety.
Eikka
3.8 / 5 (4) Apr 17, 2014
If you want to dump this in your personal water reservoir because the stuff "doesn't move around": fine. Volunteer it as a nuclear waste disposal site.


You're making it out like people would go around deliberately blowing up and melting down reactors and then sinking them.

Nobody is that idiotic, and dumping nuclear waste in the sea is already internationally illegal.

The real concern is that out of all the platforms in the world, you'd maybe have a single serious accident every 50 years. Yes, it would pollute the oceans, but for as much as it would, I think it wouldn't really matter.

Because at that point you'd be hysterical about radiation doses that are fractions of the naturally occurring background radiation, while eating a banana and driving around in a diesel bus. It's completely unreasonable.
Eikka
4 / 5 (4) Apr 17, 2014
The rest of us would rather not have that gunk in our food chain.


But you're perfectly happy about mining for rare earth minerals to construct solar cells and batteries and windmills, causing massive heavy metals runoffs into the ecosystem, and the highly toxic and carsinogenic waste streams from refining/recycling the materials.

Wait.

I think I understand it now. Nuclear waste is homeopathic pollution. The more dilute it is, the more harmful it gets. That's why people are so absolutely terrified by it, because any attempt to diminish the environmental impact actually makes it worse!
Eikka
3.3 / 5 (3) Apr 17, 2014
So what exactly would they do if the thing sinks


Btw.

If a reactor sinks in water, it is easier to clear the debris around it than if in open air because water is an excellent radiation shield. Clearing crews can get right in close to the broken ship to dismantle it and lift the reactor out.

One could in theory swim in a pool of spent nuclear fuel rods quite safely, all the way down to about 3 feet of the rods, if I remember it correctly.

bluehigh
5 / 5 (2) Apr 17, 2014
If something goes wrong on one of those platforms then guess what happens:


Godzilla lives again?
TheGhostofOtto1923
1 / 5 (1) Apr 17, 2014
You were talking about "radiation" washing ashore, not radionuclides. That was just plain scare tactics tailored for people who don't understand radioactivity
Its understandable that aa would use mindless, irrational scare tactics because that's what he himself is most susceptible to.

Russia is already building these things.

"The stations are to be mass-built at shipbuilding facilities and then towed to the destination point in coastal waters near a city, a town or an industrial enterprise. Although the world's first floating nuclear power station was MH-1A built in the 1960s into the hull of a World War II Liberty Ship, the Rosatom project represents the first mass production of that kind of vessel. Early plans supposed at least seven of the vessels to be built by 2015... Construction of the first floating nuclear power station, Akademik Lomonosov, started on 15 April 2007... Each vessel has two modified KLT-40 naval propulsion reactors together providing up to 70 MW..."
WillieWard
not rated yet Apr 17, 2014
It could be safer if it were aneutronic fusion.
adinb
not rated yet Apr 17, 2014
How do establish a water flow around the containment vessel passively (without pumps)? Do you use thermal gradients deltas, or....?