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Germany shuts down seven reactors‎ because of Fokushima

reuters.com

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Re: Germany shuts down seven reactors‎ because of Fokushima

#121

Post by lispm »

drzaiusapelord wrote: post #10
jrockway wrote: post #3

Nice to know that there is another country out there that's as irrational as the US. Does Germany have a lot of tsunamis?

Naww, but soon they'll have more people with lung cancer from breathing all that burning coal and oil for energy. I think this is a political move that is going to help in the next election. The "greens" will see this as a handout to them and nuclear power is too complex and scary an issue to have someone defend it properly. Oh well, back to fossil fuels!

I don't think lung cancer based on that is that common as it used to be. The filters in the new coal power plants can be as effective as 99,5%.

Second where I live in North Germany the wind mills already flood the network on windy day with more electricity than consumers can take.

Re: Germany shuts down seven reactors‎ because of Fokushima

#123

Post by jpiasetz »

hollerith wrote: post #106
krschultz wrote: post #54

Earlier quoted context omitted.

K=1/2*mv^2? My intuition (as a mechanical engineer, desinging military systems as my day job) is that the F16 going supersonic is far worse. Either way, there is no possible way you have enough information to make any of the claims you just made. A better question to ask yourself how safe your highway transportation is, because within an hour of my house we've had 15 people killed in bus accidents in the last 72 hour…

Huh? The mass of the A380 is at least 100 (and perhaps 1000) times the mass of the F16 (just picture them flying side-by-side and note the area of sky obscured by the A380 versus the F16 and note that although the mass density of the F16 might be higher than the A380 because much more of the mass is engine, it is not twice as dense as the A380). And no way can the F16 go 10 times as fast as the A380. So the kinetic e…

Weight (Maximum take off)

  A380 = 569000 kg [1]

  F-16 = 19200 kg [2]
Top Speed

  A380 = 945 km/h = 262.5 m / s

  F-16 =  2410 km/h = 669.444444 m / s
Kinetic Energy

  E = 0.5 * m * (v^2)

  E380 = 0.5 * 569000* (262.5^2) = 19 603 828 125

  EF16 = 0.5 * 19200 * (669.444444^2) = 4.30229629 × 10^9
[1] http://en.wikipedia.org/wiki/A380

[2] http://en.wikipedia.org/wiki/F-16_Fighting_Falcon

That said I think it probably doesn't matter. On impact the plane would breakup and you probably wouldn't get full force from either and also I bet it was built with more then a factor of 10 safety factor.

Re: Germany shuts down seven reactors‎ because of Fokushima

#124

Post by evgen »

paganel wrote: post #70
Qz wrote: post #52

Earlier quoted context omitted.

KE = 1/2mv^2, so depending on how supersonic they're talking about, it could very well withstand an A380 impact as well as a supersonic F16.

Supposedly an A380 carries much more fuel, whose explosive power might make up for the difference in impact speed.

The fuel is a fire risk, not an explosion risk. To get a decent explosion you would need to mix the fuel with a lot of air in the right ratio. Real life is not like the movies/TV; sealed tanks of gas are unlikely to explode if punctured by flaming debris. As an example, the fuel in the planes is what eventually killed the WTC buildings, but this was because the fuel burned, not because it exploded.

Re: Germany shuts down seven reactors‎ because of Fokushima

#125

Post by afterburner »

bhousel wrote: post #69
jgrahamc wrote: post #16

Earlier quoted context omitted.

Which beliefs? That a nuclear power station situated in a major earthquake zone next to the coast could magically survive a 9.0 earthquake and a tsunami? Right now, we don't know how serious this situation is, it could be that this will end with a small amount of radiation leaked and four reactors that have to be decommissioned. Or it could end with a major environmental disaster. We simply don't know yet. I'd cautio…

I've done a ridiculous amount of reading the past few days, and I still believe that nuclear power is probably the best source of power that we have available to us. But I didn't realize that keeping a reactor vessel (and fuel storage pools) cool after the reactor has been scrammed is such a challenge. I also didn't know that hydrogen explosions are a normal byproduct of cooling down a reactor core. Yes, I know that…

"I really do believe that we should be investing in these technologies to make nuclear power safer."

This is my major beef with nuclear power. We could invest scads of dollars into expensive and fairly mature nuclear technology, or we can put that same amount of money into renewables which have tremendous room for improvement (that and money towards the advanced power grid that would make renewables also more efficient). I think it is a mistake to neglect the opportunity to shift focus.

Re: Germany shuts down seven reactors‎ because of Fokushima

#126

Post by more_original »

ugh wrote: post #51
more_original wrote: post #22

Context: The previous government had decided to phase out nuclear power by 2020. After the last election the current revoked that decision and even allowed old power plants that were due to be shut down to operate longer. So, if they hadn't revoked that decision, the seven reactors we are talking about her would have been shut down already or would be about to be shut down anyway.

I don’t think all those seven nuclear power plants would already have been shut down – more like three or so. I listened to the press conference this morning and it sounded like their decision to shut down all seven pre-1980 plants had something to do with the relevant law. This law makes a distinction between pre-1980 and post-1980 plants which can be used to justify their decision. If the government wants to shut d…

You're right, that's what I meant to say with "or would be about to be shut down". Three of the seven would have been shut down this year, another one in 2012 and the final three in 2013 (source: http://de.wikipedia.org/wiki/Liste_der_Kernreaktoren_in_Deut...). Last year it was decided to extend the lifetime of these reactors to 2019 or 2020.

Re: Germany shuts down seven reactors‎ because of Fokushima

#127

Post by masklinn »

reirob wrote: post #117
makmanalp wrote: post #82

Earlier quoted context omitted.

Magically? We're made to believe that nuclear power plants are built for all sorts of compounding contingencies. Take a look at the list of significant earthquakes in Japan: http://en.wikipedia.org/wiki/List_of_earthquakes_in_Japan 8,3, 8.5 and 8.4 are three major earthquakes I see before mid-20th century. If you're building a power plant, it should survive a large safety factor above the largest earthquake you have…

Looking up in http://en.wikipedia.org/wiki/Richter_magnitude_scale the Richter Scale "is a base-10 logarithmic scale obtained by calculating the logarithm of the combined horizontal amplitude (shaking amplitude) ...". This means that a Richter magnitude of 9 has a 10 time bigger shaking amplitude than Richter magnitude 8. I do not know for which earthquake magnitude the power plants in Japan were planned but apparent…

Note that the richter scale is outdated, the current scale (while sometimes mis-named Richter) is the Moment Magnitude Scale.

It is also a logarithmic scale.

Furthermore, as with Richter,

> This means that a Richter magnitude of 9 has a 10 time bigger shaking amplitude than Richter magnitude 8

Yes, and a bit above 30 times the energy released (2 magnitudes indicate a thousandfold increase in energy)

Re: Germany shuts down seven reactors‎ because of Fokushima

#129

Post by afterburner »

newguy889 wrote: post #35
xlpz wrote: post #25

Earlier quoted context omitted.

What potentially devastating consequences would there be if instead of a nuclear plant a windmill had been hit by an earthquake, tsunami and explosion? I honestly fail to be impressed by this kind of reasoning about nuclear energy's safety. Disclaimer: I still think fission power might be better in the long run than coal power (catastrophic global warming is worse than any nuclear disaster), but I'd rather do without…

How much land needs to be paved over with windmills to equal the power output of one nuclear plant?

A handful of square meters per windmill, unless it's off shore and then it's none (as in no land). You realize windmills for energy production dots the Danish landscape, placed in handfuls in the middle of farms, right?

Re: Germany shuts down seven reactors‎ because of Fokushima

#130

Post by pjscott »

afterburner wrote: post #125
bhousel wrote: post #69

Earlier quoted context omitted.

I've done a ridiculous amount of reading the past few days, and I still believe that nuclear power is probably the best source of power that we have available to us. But I didn't realize that keeping a reactor vessel (and fuel storage pools) cool after the reactor has been scrammed is such a challenge. I also didn't know that hydrogen explosions are a normal byproduct of cooling down a reactor core. Yes, I know that…

"I really do believe that we should be investing in these technologies to make nuclear power safer." This is my major beef with nuclear power. We could invest scads of dollars into expensive and fairly mature nuclear technology, or we can put that same amount of money into renewables which have tremendous room for improvement (that and money towards the advanced power grid that would make renewables also more efficie…

Nuclear technology has a lot of room for improvement, too. There's some improvement that's relatively straightforward, like bringing capital costs down; China is working on this, with great success, as they can now construct CPR1000 plants cheaper than coal plants of the same size.

Then we have more exotic and longer-range options, like breeder reactors (both uranium and thorium), small modular reactors, Brayton-cycle gas turbines instead of steam turbines, and so on. Nuclear technology seems stagnant, but the reasons for this are political rather than technical, and that's changing now.

Edit: I forgot to mention clever applications that are possible without reactor modifications, like high-temperature hydrogen production, ammonia synthesis, desalination with waste heat, and so on.

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