Location: Near the banks of the Kuryong River (九龍江), Pun’gang-jigu (分江地區), Yŏngbyŏn-kun (寧邊郡), North P’yŏng’an Province (平安北道), North Korea

Subordinate to: Probably the Fifth Machine Industry Bureau (第5機械工業局), which is also known as the "Fifth General Bureau" (第5總局), Second Economic Committee (第2經濟委員會),  National Defense Commission (國防委員會); and/or Department No. 32 (第32部) under the Nuclear Chemical Defense Bureau (核化學防衛局), Ministry of the People’s Armed Forces (人民武力部), National Defense Commission (國防委員會)

Primary Function: Testing high explosives and trigger devices for nuclear weapons

Description: In late October 1990, US government officials revealed the presence of a high explosive test site in Yŏngbyŏn-kun during a briefing to Japanese Foreign Ministry officials in Japan. At the briefing, the US officials presented KH11 satellite imagery of North Korea’s nuclear complex in Yŏngbyŏn-kun. The satellite imagery indicated craters on the northern banks of the Kuryong River, which US officials concluded were traces of explosions from high explosive tests.

North Korea reportedly conducted more than seventy high explosive tests between 1983 and 1991, and at least three tests between 1997 and 1998. According to South Korean press reports, the US Defense Intelligence Agency informed the South Korean government in December 2002 that North Korea has conducted an additional seventy tests since 1998.

The first seventy (to eighty) high explosive tests were presumably conducted at the Yŏngbyŏn High Explosive Test Site. According to a South Korean intelligence source, the first seventy explosive tests were probably for assessing the quality of high explosives, while the more recent round of testing since 1998 was likely the final tests of a high explosive trigger device for a nuclear weapon. The Yŏngbyŏn High Explosive Test Site has probably not been in use since the early 1990s.

The site of most recent testing was unclear around the time the reports came out. However, other South Korean intelligence sources said that North Korea was unable to use the Yŏngbyŏn High Explosive Test Site after the 1994 Agreed Framework, so it started building a new test site in Yongdŏk-dong. These intelligence sources said that as of 2002 North Korea had conducted seventy high explosive tests at this site. In early July 2003, South Korean National Intelligence Service director Ko Yŏng Ku corroborates this assessment, reporting to the South Korean National Assembly that the seventy high explosive tests that have been conducted in North Korea since the signing of the Agreed Framework occurred in Yongdŏk-dong in Kusŏng. [Note: While Ko Yŏng Ku refers to the seventy high explosive tests conducted by North Korea since the 1994 signing of the Agreed Framework, he is likely referring to the most recent tests, which other sources claim did not begin until 1997.]

The three high explosive tests conducted between 1997 and 1998 were reportedly not conducted at the Yongbyon site. The tests were reportedly conducted at a test site in the city of Kusŏng. [Note: the Yongdŏk-dong High Explosive Test Site (the Kŭmp’ung-ri High Explosive Test Site) is in the City of Kusŏng.]

Defector Lee Ch’ung Kuk claims that North Korea conducted one nuclear test in Russia and two tests in Ukraine in 1992 after US reconnaissance satellites discovered the Yŏngbyŏn High Explosive Test Site. Lee also claims North Korea has a high explosive site on a mountain in Sŏg’am-ri (石岩里), P’yŏngwŏn-kun (平原郡), South P’yŏng’an Province, and he claims to have observed the test of a high explosive nuclear trigger device at this site in October 1993. However, his claims are unsubstantiated.

	Updated August 2003

Key Sources:
“Amerikaga Keikoku Kitachosen Genbakukoujouno Kyouhu,” Shukan Bunshun, 29 November 1990, (Tokyo: Bungeishunju), pp. 38-42; Kang Su Ung, “Pukhan, Yŏngbyŏn’e Wŏnjaro 3 Ki Poyu/Mi, Ilbon’e Briefing,” Taehan Maeil, 22 November 1990, p, 6, in KINDS, <http://www.kinds.or.kr>; "North Korea Has Nukes: U.S. Expert," Jiji Press, 16 November 1990, in Lexis-Nexis, <http://web.lexis-nexis.com>; Yu Yong Wŏn, “Puk, Geneva Habŭi Ihu 70 Ch’arye Haekkop’okshilhŏm/Sushipch’arye’ŭi Shilhŏmmanŭrodo Plutonium Haekp’okt’an Chaejo Kanŭng,” Chosun Ilbo, 19 December 2002, p. 8, in KINDS, <http://www.kinds.or.kr>; ROK Ministry of National Defense, Taeryangsalsangmugi (WMD) Mundappaekkwa:Hwa Saeng Pang Missile Ŏlmana Algo Kyeshimnikka? (Seoul: Ministry of National Defense, 2001), pp. 93-94; Sŏng Tong Ki, “Pukhan Haekp’okt’an 1, 2 Kae Chesomuljil Hwakpo Ch’ujŏng,” Donga Ilbo, 19 December 2001, p. 2, in KINDS, <http://www.kinds.or.kr>; Ryukichi Imai, “Tokyo Can Help End Nuclear Chaos: Making Russia Safe Will Benefit Japan – and Global Security,” Nihon Keizai Shimbun, 12 April 1993, p. 7, in Lexis-Nexis, <http://web.lexis-nexis.com>; Im Sun Man, “Haekkaebal Wŏlbukkwahakja 4 Myŏng’i Chudo,” Kukmin Ilbo, 22 June 1990, p. 6, in KINDS, <http://www.kinds.or.kr>; “Pukhan ‘Kop’okpal’ Shilhŏm/Ch’oekŭn Yŏngbyŏnsŏ...Haekkaebal Chŏntangye Ch’ujŏng,” Chosun Ilbo, 27 June 1991, p. 2, in KINDS, <http://www.kinds.or.kr>; Kim Wŏn Hong, “Puk, Naenyŏnbut’ŏ Wŏnjat’an Ponkyŏk Saengsandangye,” Taehan Maeil, 9 November 1991, p. 3, in KINDS, <http://www.kinds.or.kr>; Lee Sŏk Ku, “Mikuk Ŭihoejosakug’i Chaech’ul’han ‘Puk Haekkaebalkyehoek’ Yoji,” Joongang Ilbo, 9 April 1992, p. 5, in KINDS, <http://www.kinds.or.kr>; “‘Puk Haekbalsanŭngryŏk Poyu’/Kwŏn Kukpang Pogo,” Kukmin Ilbo, 16 March 1993, p. 1, in KINDS, <http://www.kinds.or.kr>; Peter Seidlits, “Korea Continues Build-up Nuclear Arsenal,” South China Morning Post, 19 December 1993, p. 1, in Lexis-Nexis, <http://web.lexis-nexis.com>; “‘Pukhan, Imi Haekp’okt’an Cheso’/Kilo Kŭp Sohyŏng 5-6 Kae/Hongkong Chi Podo,” Hankook Ilbo, 20 December 1993, p. 2, in KINDS, <http://www.kinds.or.kr>; Chu T’ae San, “Pukhan/Pimil Haekshilhŏm/Kanŭng’hada/Kukpangyŏn Shin Sŏng T’aek Paksa Nonmunsŏ Chujang,” Segye Ilbo, 20 April 1994, p. 9, in KINDS, <http://www.kinds.or.kr>; Pak Yong Ch’ae, “Changnyŏn 10 Wŏl Pukhaekkip’okshilhŏm Ch’amsŏk,” Kyunghyang Shinmun, 27 September 1994, p. 4, in KINDS, <http://www.kinds.or.kr>; Kim Min Sŏk, “Puk Yŏngbyŏn’pukŭnsŏ Haettanŭn Kop’okshilhŏm Mwŏnga,” Joongang Ilbo, 26 November 1998, p. 6, in KINDS, <http://www.kinds.or.kr>; Joseph S. Bermudez, Jr., “Exposing North Korea’s Secret Nuclear Infrastructure—Part Two,” Jane’s Intelligence Review, August 1999, p. 44; David E. Sanger, “C.I.A. Said to Find Nuclear Advances By North Koreans,” New York Times, 1 July 2003, p. A1, in Lexis-Nexis, <http://web.lexis-nexis.com>; An Chun Hyŏn, “‘Sohyŏng Haekt’an’du Puksŏ Kaebaljung’/NYT ‘Mi, Haekshilhŏmshisŏl Hwagin’,” Hankook Ilbo, 2 July 2003, in KINDS, <http://www.kinds.or.kr>; Lee Mi suk, Kim Kyo Man, “Puk Haekshilhŏmjang Saesashil Anida,” Munhwa Ilbo, 2 July 2003, in KINDS, <http://www.kinds.or.kr>; Lee Chong Hun, “Puk Haekt’an’du Chejogisul Ŏnŭ Sujuninga/1t Miman Sohyŏnghwaddaen Haekwihyŏp Hyŏnshilhwa,” Donga Ilbo, 3 July 2003, in KINDS, <http://www.kinds.or.kr>; “Further on Report Cites ROK Spy Chief on DPRK High-Explosive Tests,” Hong Kong Agence France Press, 9 July 03, in FBIS Document ID: JPP20030709000100; Kim Min Chŏl,  “Puk 70 Yŏch’arye ‘Yongdŏkdong Ko’p’okshihŏm’ P’ajang,” Chosun Ilbo, 11 July 2003,  in KINDS, <http://www.kinds.or.kr>.