I am getting tired of reporters referring to Fukushima Daichi # 2, 3, or 4. The name of the plant is not Fukushima Daichi.
Dai is a counter used in Japanese that is the equvalent of “Number”.
So it is Fukushima Dai-ichi, Dai-ni, Dai-san, or Dai-yon. Fukushima no dai ichi genshiro, if you want to be totally correct.