軽けい水すいけいすいMeanings1nounlight waterTechnical term for ordinary water (H₂O) as opposed to heavy water (重水). Used in nuclear engineering and chemistry.軽けい水すい炉ろは軽けい水すいを冷れい却きゃく材ざいとして使つかう原げん子し炉ろです。A light-water reactor is a nuclear reactor that uses light water as a coolant.
