Enforcement Rules for the Nuclear Emergency Response Act Article 13

When a nuclear accident occurs, or is concerned of occurring, licensees shall, in accordance with Paragraph 23.1 of the NER Act, notify the competent authorities of various levels stipulated in Article 3 of the NER Act by telephone within 15 minutes, and in writting within one hour.
中文原文 核子事故緊急應變法施行細則第13條
核子事故發生或有發生之虞時,經營者應依本法第二十三條第一項規定,於十五分鐘內,以電話通報本法第三條所定之各級主管機關,並於一小時內以書面通報。

English translation for reference only; the Chinese text prevails. Not legal advice.