agree with tombraider about the risk Japan represents to the world ... Japan is a death trap not worthy of refugees

Fukushima = Godzilla

The OP is about Japan's policy not to take in immigrants.
I agree Fukushima has detroyed Japan but not all of Japan and not all at once.
However, there has to be a population migration to other areas within the island chain because of the radiation/contamination.
Their arable land has shrunk. You don't take in boarders when half your house has been burned out.
Plus, with the water cycle in mind, the radiation is washing out to sea contaminating the local fisheries and the fisheries within those oceanic currents.
You don't take in boarders when your food supply is restricted.

Japan has already experienced how radiation affects births and child development (Hiroshima and Nagasaki). Sure their population is declining. Nobody wants to have children that glow in the dark. But, just like Hiroshima and Nagasaki, the Fukushima disaster will pass. If Chernobyl is any indication, its gunna take a long time. Plus, that area is already prone to tsunami so the contamination could be reawakened in the future by stirring up the surface.

Japan is doing the right thing,
as far as refugees go.