Earthquake/Tsunami in Japan
- Thread starter DuckThor Evil
- Start date
I believe that the buildings that have had the top "blown off" at reactor #1 and reactor #3 don't serve much purpose other than keeping the operators dry (i.e. nothing to do with "containment" in the nuclear sense). And they are (apparently) designed to blow out (rather than collapse) to prevent any damage to the reactors inside.
I am well aware of why they are built near a body of water. Better to use a different body that will not have a tsunami though. Earthquake + tsunami doesn't happen unless you are near the ocean. Otherwise they go together too well. I was impressed when I saw they were built in the 70s though. Good job considering.
the new designs have reactor cores below ponds and must pump water OUT to keep reaction running. No power = flooded reactor with control rods (grid in this case) in place.
Nope. It just needs to be enough water that it doesn't all evaporate before the reactor cools (about ten days).
A modern 1GWe reactor develops around 3GW heat. Eight hours after shutdown, residual heat production has fallen to 30MW (1%).
Water's specific heat of evaporation is slightly above 2MJ/kg, so you're boiling off 15 litres/second or 50 tons/hour.
Cheers
Also that design seems to be great at generating an awful lot of steam / hydrogen and pressure in a short period of time. I don't know enough about it though, it must have some merit or trade-offs.
Changing the subject slightly it's an incredible thought that the workers there had to mentally cope with not just one reactor causing problems but 4 and also with the threat to their health as well and perhaps not knowing about their families. They have my admiration.
Whether it's natural or not is not important. What's important is that nuclear reactors are not as robust as people think. No matter how "unreasonable" you may think the fear is, the reality is that four supposedly well designed "safe" nuclear reactors, despite successfully performed scram, exploded three times and released non-trivial amount of radioactive materials into the atmosphere. The fact that hundreds of thousands of people have to be evacuated does not help either. To put it simply, a simple ire could destroy the cooling system and make a perfectly good nuclear reactor into similar situation.
Personally I believe that nuclear is the most viable near-term solution for our energy needs, but apparently we need to more carefully reconsider the design and safety margin of nuclear reactors. Simply saying such fear is not reasonable is not very convincing.
1%? For all I know, it drops to 10% instantly, and to 2% in next 24h, not 1% in 8h
Yes.
My point is, that a non trivial amount of heat is produced which need to be removed.
Cheers
Spent fuel is incapable of doing "meltdown", only active fuel rods do it.
To put it bluntliy majority of public are idiots. Why aren't we banning coal plants considering they are causing a LOT more radioactive waste and deaths than all nuclear power related stuff combined since the first plant went into operation?
Modern designs are made so that they don't need any kind of passive cooling systems. If anything happens they simply shut down automatically. Check out pebblebed and liquid salt reactors for more information. The reactors in Japan are using over 40y old technology. Imagine yourself getting into a freeway accident driving a car using 40y old safety systems.
Recent spent fuel rods are capable of igniting, and thus melting ... not technically a meltdown I guess. Actually something worse.
Burning fuel rods in a leaky container are not necessarily something you want to put water on.
Of course things get better. But isn't that also why we're almost guaranteed to look back at current 'modern' technology in 40 years time? 40y ago, people didn't take into account an earthquake and a tidal wave in Japan affecting all the backup systems in a bad way. And 20y ago, when perhaps someone did think that this combination could become an issue for the first time, nothing was done for various reasons.
Also, I just hear that nuclear waste storage depots have been recently damaged and are now also posing a health risk.
Most importantly, you have to almost assume by default that something is going to go wrong with a nuclear powerplant for whatever foreseen or unforeseen reason. Perhaps next time the problem is caused by someone working at a nuclear powerplant turning out to be some kind of terrorist and purposely sabotaging the plant. Or someone flies a plane or two into one drowning the place in Kerosine - perhaps the fire isn't an issue, but then the impact of that plane is. Or a freak meteor strike hits a nuclear powerplant. Or water levels suddenly rise much faster than expected and floods parts of Europe. Whatever the cause, I think that there is good reason to be extremely cautious.
And of course, all sorts of power plants form various risks. Perhaps the danger of melting the icecaps is the worse of the two evils, for instance. All things need to be considered.
Or a terrorist could be walking down the street and set off a bomb, or a terrorist could crash a plane in to a football stadium, or a freak meteor strike hits a school, or some previously-unknown solar event occurs and all of the oceans suddenly vaporise. Just about anything ever could go wrong in some way and kill people. The safest thing to do is just never get out of bed. But that'd probably kill you too. We should certainly ban cars, schools, or anything that involves 2 people being within a mile of each other, just in case.
There are things that may happen, but the chance of them *actually* happening is so small that it isn't worth worrying about, just do the best you can and hope for the best.
Yeah, but that doesn't mean idiots can simply be ignored.
Rather, ask yourself why we aren't banning cigarettes, since cigarette smoke kills far more people every year than coal power plants, and you don't even get any benefits to society from it, unlike the electricity which comes out of the coal plants.
The radioactive "waste" from coal powerplants is so diluted that it can be ignored. It's never been described as any sort of REAL problem, unlike what happens when a nuclear reactor blows its top a la Chernobyl.
It's not comparable. Cars basically didn't have safety systems 40 years ago, there were seatbelts, but that was it. Even old nuclear power plants have many backup systems.
sure its a small chance & most likely wont kill that many ppl the thing thats different is with a Chernobyl (or worse) accident in japan or some other heavily populated country/area. Bang! there goes a percentage of your country made inhabitable for decades. whereas after an earthquake etc after a rebuild its like new
I wonder if bin laden is taking notes.
20 guys take over nuclear reactor near new york, dump the cooling water, drill through the outer core (suicidal mission).
viola! far more physiological damage than flying a plane into a building