Instead of trying to move the ocean to the nuclear cores, why not helicopter the cores to the ocean?

You need to keep the fuel rods covered in water in order to move them.

At the moment, keeping the fuel rods covered in water is what the problem is.

It's a Catch-22.

Furthermore, in order to store unspent fuel rods, you need to place boron in between them, so that they don't start engaging in fission.

So there would need to be some sort of apparatus placed in the ocean that would keep the fuel rods apart. And that apparatus would need to be strong enough to withstand the force of the ocean's current, without moving or breaking. This would need to be designed and built, which would take weeks, if not months.

ETA:

The spent fuel in unit 3 and 4's pools does not need to be separated by boron, since it is spent (no longer fissile). This could theoretically be dumped in the ocean as is.

However, in the reactors and in unit 4's pool, there is unspent fuel, which is fissile. In order to prevent this fuel from undergoing fission, it is separated into pieces that are too small to undergo fission. In the reactors, control rods are used. In the spent fuel pool, it is separated by slabs of boron and the water also contains boric acid. I don't know the exact specifications of how it's stored, since the design of a spent fuel pool is unique to each plant, but I highly doubt that there is a "handy dandy spent fuel carrying frame".

I doubt they use any type of boron frame to move rods from the reactor to the pool. Even if the fuel is fissile, the simplest way to prevent it from reaching criticality is to remove it in pieces, since if only a small portion of the fuel rods are gathered together, it will not constitute a large enough mass for fission to occur.

The problem is that this unspent fuel will be fissile even if it is in the ocean. It must be prevented from reacting, even when covered by water.

There are two ways to do that. The first is to deposit a subcritical (too small) mass off the coast of Japan, and then deposit other subcritical masses off the coasts of other nations. At that point, the odds of them getting close enough to react would be astronomical. But, you'd have to transport the fuel rods for miles in order to do that, and they'd need to be kept covered with constantly refreshed water the entire time. And you'd have to find nations that are willing to have radioactive waste off their coasts, which isn't going to happen.

The second way is to place all the fuel rods together, but keep them separated by boron. They will need to remain separated by boron. In order to ensure this, the structure would have to be strong enough to withstand any type of ocean current that might occur.

Furthermore, they would definitely have to be removed at some point. The fuel rods will remain capable of reacting with each other for millions of years and the zirconium coating isn't going to last that long. The boron might not even last that long.

Depending on how long the reactors cores have been in service, the total amount of fission products they contain could be measured in tons.

That is a heck of a lot of radioactive material to dump in the ocean.

Let's bury it in a nice safe place instead.

A much cleaner solution

I guess you have no idea how hot the cores can become once they have no water or coolant .....

if you google "nuclear fuel rods" you'll have a better understanding.....

in a nutshell how do you bury something that is so hot it will actually "melt" the dirt you try to bury it with ?

based on your sci-fi qn, i'm going to respond to in a sci-fi way as nicely. human beings might have created a colony on neighbouring image voltaic structures. And in thrillions of years later the human race might have span the galaxy, provided there are not the different smart beings. Earth might have then grew to grow to be a fantasy. = >

It's probably a lot more complicated than that. How do they go in and get the stuff, package it up move it, and not contaminate the ocean?

That would pollute our ocean and fish,japan relies a lot on its fish

that seems a bit unstable exposing the cores like that.