Nothing much to say here about the financial aspects. Need to see how they react.

Best I can tell this doesn’t effect the world economy all that much.

Oil demand may initially fall some, due to a temporary reduction in consumption and maybe a refinery shut down. And domestic demand in general may fall until the rebuilding starts.

The power lost by the nuclear plants shutting down may amount to maybe 1-2% of total electric power consumption, and will be replaced but a combo of different sources.

Replacing the nuclear plants will cost something but not a lot in the scheme of things, and the new ones are even safer than the older ones, which seem to have help up reasonably well, especially considering the extreme stresses.

Govt deficit spending may go up by a small % of GDP as will the spending of insurance company and other private reserves.
And insurance companies then replenishing their reserves does the reverse.

I’d guess they govt will direct most of the rebuilding contracts to domestic companies.

I don’t see anything that makes the yen stronger?

Japan should have more than adequate resources of all types immediately available as emergency services, shouldn’t need any help from anyone, though for political purpose they will certainly accept it.

They’ve been saying for years there’s nothing left for govt to buy, so they must have thousands of emergency helicopters, millions of emergency temporary housing trailers, etc. etc. ready to go?