6ㆍ25 당시 월북해서 북한 영변 원자력발전소 초대 소장을 지내는 등 1996년 사망 때까지 핵개발을 주도했다.
He defected to North Korea on June 25, served as the first director of North Korea's Yongbyon nuclear power plant, and led nuclear development until he died in 1996.