They have six reactors. As far as I know, each reactor has 180 tons of
spent fuel rods in water pools. The pools are giant steel bathtubs
suspended in the air. Each pool starts boiling if water in it is not
cooled. The steam is moderately radioactive.

The water will not be cooled if the plan is abandoned. The plant IS
abandoned. The water is not cooled.

Some pools are already boiling, as far as I can tell, from the copious
white steam clouds emitted.

Assume the slowest development of events, that no pools are
breached. (if they are breached and dry, everything will develop a few
days faster).

If the water is not cooled, it will boil off in a week (also as far as
I know).

Then every pool will turn into a white hot pile of burning nuclear
fuel waste rods.

The pile will melt/fall through the steel bottom of the pool, to the
floor of reinforced concrete buildings, where the resulting pile/lake
of white hot material will be evaporating due to extreme temperature,
an analog of burning, but without any need for oxygen.

In any case, if those white hot waste fuel lakes stay on the surface
and do not eat through and submerge through the soil and concrete,
they will be emitting radiation for years, at a high level, and this
will end, likely, when they evaporate almost fully.

That's the bad news -- 1,080 tons of nuclear waste has, more or less,
nowhere else to go other than to the sky.

The good news, is that most of the material will fall in the Pacific
ocean, where it will dissipate. However, if winds do not cooperate,
there is enough of material to render big parts of Japan unlivable for
a long time, due to long half life of most isotopes in said waste.

The other bad news is that the prevailing winds are towards the United
States, going straight to Larry Jacques' backyard. Hopefully, most
stuff will settle down in the ocean.

If this bad scenario materializes, against my hope, then the solutions
will be dirty. One would be to drop large bombs on those buildings, in
order to spread the nuclear waste from the boiling white hot lakes,
over a large area. That would help with its cooling. Pellets spread
over several acres would cool down somewhat. Then, concrete could be
air dropped over the wide area just to encase everything. Concreting
the reactor buildings, pretty much, is impossible due to lack of
access to the inside, and due to the active lakes of spent fuel.