Dropping Coolant from Helicopters -- When All Else Fails

As word spread that Japan was trying to find a means of putting coolant on its critical reactors from the air without killing her pilots, I read a someone's comment on another site...

If this was a movie, right about now, someone would come up with a daring but risky plan that would just barely work.  I'd really like to see life imitate art, but I don't think it's going to happen in this case.

To which I replied...

Remote control.

Take whatever DARPA has for remote controlled and autonomous vehicles, plus whatever the military and others have for aircraft, particularly helicopters.

See what kind of major earthmoving equipment you can get in there.

See what kind of guided helicopters you can move in that direction. Also, whether or not any blimps in the area could be remotely controlled, rigged up with a harness moving material, and then able to release that material while slowly moving over one of the reactors.

If you get desperate, or feel a mass of sand and/or boronic acid can't do too much harm, opening the bottom of an underslung box beneath a relatively fast-moving vehicle, such as a drone, might also get a ton or so of material on the target.

Finally, if none of that works, or is inadequate...

The reactors are in a line. Again, if you can drop the sand and/or boron safely by itself, could you take certain aircraft and start targeting each reactor with de facto payloads of whatever dampening/covering materials you were putting in place, assuming that you wouldn't be damaging reactor integrity further, and that near misses would mostly end up on other reactors, or nearby (perhaps covering other contaminants).

In that case, you could probably employ all kinds of hardened U.S. aircraft, possibly from safer standoff distances than helicopters can manage. U.S. bombers tend to be built with nuclear incidents in mind, and many transport and cargo aircraft can open their doors while in flight to release people or cargo.

Speaking of which, there's the old parachuting materials trick. The U.S. used to have a project for a retrojet cargo box that could be dropped from an airplane and which would slow its own descent using mini-jets. I don't know if that ever reached prototype stage, much less real use, but it could probably be guided if it existed.

But failing that, small, simple propellers or miniature jets or even basic controls (as with a glider or aircraft) could guide the descent of large, parachuting packages. If necessary, they could be made to pop open by remote order, or could simply be designed to break up on impact -- whatever turns out to be best for the circumstances and the location where they are being dropped.

Aside from that...

How radiation resistant are Harriers and hover-capable Joint Strike Fighters?

Could you attach cables or other supports to such a plane's weapons hardpoints, undersling some kind of relatively aerodynamic, robust container (without getting too close to the turbofan, when in use), and rig the systems so all the hardpoints could release at once, thus dumping a payload? If you really needed a slower vehicle for targeting your drops, these could at least get in and out of the area a lot faster, and the JSFs are probably a bit better shielded against radiation. Throw in protective gear and it might have a chance.

And failing that... you may honestly have to ask for a lot of volunteers for the high-risk option, and hopefully have enough that you can rotate them safely.