A Japanese engineer who helped build reactor 4 at the Fukushima No. 1 nuclear plant said such plants are inherently unstable, urging Taiwan to ditch atomic energy for renewable resources.

Mitsuhiko Tanaka, arriving in Taipei on Tuesday with a delegation of Diet members for a six-day visit, told a press conference Wednesday that the 1986 Chernobyl disaster changed his views on nuclear power.

"Nuclear accidents are bound to happen someday, only that we don't know when they will happen," he said.