Complex sentence: India, having successfully developed a miniaturised reactor for submarine application, is developing "Arihant"-class nuclear submarines, the first of which is undergoing sea trials and induction is expected during mid- 2012.
Split into simpler sentences: India, having successfully developed a miniaturised reactor for submarine applications, is developing "Arihant"-class nuclear submarines. One is undergoing sea trials and induction was expected during mid- 2012.