By the way, I HATE nuclear energy. Until the world finds away to properly recycle or dispose of the radioactive waste products, they have no business using it. Storing it on-site is NOT a solution - as the recent crisis in Japan demonstrates - you can't plan for every natural disaster.
You need to go get caught up to speed on modern nukes, and get your facts straight.
Japan wasn't storing it "on site", they were in the process of shutting down very old Generation I reactors due to age / safety issues. To shut them down you need to remove their fuel rods and cool them in a big pool of water until they can be safety moved to permanent storage. Funny thing is ... it was the reactors that hadn't had their rods removed that were the problems, the empty reactors and fuel ponds were fine. One of the ponds cracked and they had to do a quick repair and eventually transfer the material, but that wasn't the big problem.
Next is that Gen IV MSR / LFTR's do not "store on site" there is no storage required. They do on site reprocessing of their fuel. Most older reactors use a big pool of water with the fuel material submerged and excited until it starts fissioning. The neutrons transfer their energy into the water which cause's it to heat up and eventually turn into steam / turbine. This was the type of reactor used at the Japan incident, it's a VERY VERY OLD design and has some glaring safety issues. MSR / LFTR's have different design's but the core concept is that the Uranium fuel is dissolved into a salt compound that has been heated until it's a liquid. The material inside the salt is excited until it starts fissioning, the salt acts as the moderator (what the water did for early design's). The salt is pumped in a big circle with cooling lines full of water running through it, the water is heated and travels to another set of heat exchangers, there it heats a second water cycle that turns the turbines. Due to this there is no radioactive water getting near a steam turbine. Now the salt doesn't sit there, as the fuel is spent the salt is pumped into the adjacent reprocessing building where new fuel is mixed into the salt which cause's the old fuel to be recycled again (very short / simple explanation for a very long / complex process). The reprocessed fuel is then sent back into the reactor. It's a big cycle with the fuel constantly being reprocessed until all Uranium has been depleted, which should happen once every decade or three.
There are two big differences between the older and newer designs. First is fuel consumption. Older designs' rely on graphite fuel rods that contain fuel pellets (enriched and regular uranium mixed together). Regular uranium can not sustain a fission reaction on it's own, it's too slow. You need unstable enriched uranium mixed in with it to act as a starter. Once that enriched uranium is depleted the regular uranium can not longer sustain a reaction and is left over as fuel ash. You can't add too much enriched uranium or you risk creating a mixing that explodes on it's own. This leaves engineers with a problem, you get lots of unused uranium that you can't burn and must be kept as nuclear waste for long periods of time, you end up only burning about 1~2% of the burnable fuel. With a Gen IV MSR / LFTR the fuel is dissolved in a salt, thus once it's consumed it's enriched uranium you can just add more at the on-site reprocessing facility, this reduces the amount of unburned uranium ash by about 10~100x. Instead of burning 1~2% of the usable material you end up burning 95%+ of it. This also has the side effect of next to no waste being created, there is no unspent uranium ash inside radioactive graphics fuel rods that needs to be stored. You just keep reprocessing it until it's all been burned, then add a fresh batch of salt in while the old salt gets reprocessed at another facility.
Second difference is in the safety mechanisms. Older Gen I / II reactors use water as their moderator, water that gets very hot and is under lots of pressure. This creates the need to actively cool the water during a reactor emergency, otherwise the water gets so hot that it explodes in steam explosion. That's bad, very bad, it would release radioactive material into the atmosphere. The guys at Japan were able to avoid that from happening, but only barely. In a MSR / LFTR the salt is incapable of exploding, and if it cools it becomes inert and no reaction can happen. To guarantee this those reactors are designed with a freeze plug at the bottom of the reaction chamber that must be cryogenicly cooled. If the plug isn't cooled then it melts which released the salt into a boron laced chamber under the reactor where it cools and becomes inert and safe to handle. This concept is known as "passively safe", a safety mechanism that doesn't require active power to maintain.
Anyhow there is so much that people need to learn to understand the discussion on nukes. Otherwise their just flapping their lips / fingers and expelling hot air.
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