かく分裂 ぶんれつ連鎖 れんさ反応 はんのうであれば
kakubunretsurensahannōdeareba

Noun
Da Copula

The "-eba" conditional form ("if/when…") of 核分裂連鎖反応

1. if it were nuclear chain reaction; were it a nuclear chain reaction

Ba Conditional
Physics