Well, they’re not entirely dumb. So far the radiation is minimal, and as usual is blowing eastward across the Pacific, not toward China.
But the recommendation IF you are exposed to high radiation levels is to take potassium iodide pills.
And table salt contains—potassium iodide.
Probably not enough for full protection, I would guess. But better than nothing. My salt container says that it provides 45% of the daily dose of iodide, which I suppose means that if you consume an average daily amount of salt it would cut absorption of radioactive iodide roughly in half.
Better than nothing.
Salt would do zilch, nada, nair, nothing. The amount of salt you would have to eat would kill a guy.