The History of the North Korean
Program since the 1930s. DPRK Atomic Bomb
North Korea recently conducted their third underground nuclear
test. Experts agree that the nuclear fuel used in the first two was
plutonium, made from natural uranium in a Soviet-designed breeder
reactor. More than a month after their most recent test in February of
this year, however, despite the use of sophisticated collection means,
the U.S. was unable to determine if the nuclear fuel was in fact
plutonium or rather Highly Enriched Uranium (HEU), which if true,
experts say, would represent a significantly enhanced capability. Back
in 2000, a female worker at an HEU laboratory at the Yongbyon Nuclear
Research Center defected to China, and then later to an unidentified
Kim Jong Il and_Kim Il sung
During her June 2002 interview, Ms. Jung Chung-ok  was asked thirteen
questions. Her answers, and a hand-drawn map of the facility, were then
published in the Japanese newspaper Yomiuri Shimbun, but not in any
American publication as far as I can tell. Some believe that Ms. Jung’s
revelations led Kim Jong-il to admit — during high-level talks in
Pyongyang later that year between U.S. Assistant Secretary of State
James Kelly and North Korean officials — what the United States, Japan,
and South Korea had feared for nearly a decade: North Korea was pursuing
a nuclear weapons program. At the White House, reporters were told that
the Chinese were stunned upon learning of North Korea’s confession since
Pyongyang had managed to keep their nuclear weapons program a secret for
First, Ms. Jung was asked about her family and to describe how she
became involved in Pyongyang’s nuclear weapons program. She said she was
born in Pungseo-gun (county), Ryanggang Province in North Korea on
August 2, 1955. After her father died in 1957, Ms. Jung said that her
mother was abducted by the Central Party. She, her mother, and her two
elder sisters were then transferred to a special base of the Atomic
Science Committee. After graduating from Pyongyang Physics College in
the summer of 1974, Ms. Jung began work at Office 25 of the 304th
Research Office of Atomic Energy Science until her dismissal on February
21, 1999. She defected the following year.
When Ms. Jung was then asked how the North Koreans were able to trick
IAEA inspectors, she offering the following explanation. The underground
facilities, Ms. Jung said, were constructed by the 66th Industry, deep
beneath Yak Mountain (Yaksan) “at a huge human cost.” Many workers died
in various accidents during construction, Ms. Jung said, which began in
1965 and was completed five years later. Several female researchers who
were inadvertently exposed to large doses of radiation gave birth to
deformed children. The complex is extremely large and well illuminated,
Ms. Jung said, with underground caves branching out into various
interconnecting tunnels. Concrete walls block the entrance, which is
“large enough for trucks to enter,” and clever camouflage hide it from
outsiders. The caves are used to hide lab equipment and other evidence
of a nuclear weapons program in case of inspections. During the IAEA
inspection, for example, tell-tale equipment and materials were secretly
moved into the Yaksan cave, and laboratory staff members wore military
uniforms to hide their true roles.
According to Dr. Kang Ho-je, a South Korean authority on North Korean
science technology, the weaponization of nuclear technology began in the
late-1960’s or early-1970’s, apparently as the result of a “confluence
of change in the international situation, North Korean domestic
politics, and the state of North Korean science.” According to a 1988
CIA report, the Yongbyon Nuclear Research Center was established with
Soviet assistance in the 1960’s, and was the “focal point” of a North
Korean nuclear effort. Until the 1980’s, the CIA report said, the center
consisted of an operations area with a 4-MW (megawatt) research reactor,
supplied by the Soviets under IAEA safeguards, and a large support area.
Since North Korea’s expansion program, which began in 1980, the CIA
said, Pyongyang constructed additional support buildings and a 10-30 MW
graphite-moderated gas-cooled reactor which was fueled with natural
uranium, mined in the Hamhung and Ch’olsan areas of North Korea.
Although the new reactor had been in operation since October 1987, a CIA
report the following year concluded, “We have no evidence that North
Korea is pursuing a nuclear weapon option, but we cannot rule out that
Yongbyon Nuclear Research Center
When Ms. Jung was asked to discuss the origin of Pyongyang’s nuclear
weapons program, she said it began in the 1950’s during the Korean War
when Kim Il-sung, Kim Jong-il’s father, ordered Lee Hak-mun, a two-time
national hero medal winner, to develop nuclear weapons. Lee Hak-mun then
recruited prominent South Korean scientists such as Dr. Do Sang-rok, Dr.
Han In-suk and Dr. Lee Sung-gi to carry out nuclear research. Do Sang-rok,
a quantum field theorist who conducted North Korea’s first experiments
in nuclear reactions, defected to Soviet-occupied North Korea in May
1946, only nine months after World War II had ended. By September of
that year, Dr. Do became the head of the physics and mathematic
departments and chief of research at what would later become Kim Il-sung
University. Dr. Do also built North Korea’s first particle accelerator
and carried out the North’s first nuclear experiments. He later
enthusiastically helped establish North Korea’s main nuclear facility at
Bungang, some fifty miles north of Pyongyang.
Other South Korean scientists were reluctant to aid North Korea’s
nuclear weapons program. According to Kim Dae-ho, who requested asylum
at the South Korean embassy in Beijing in 1994, Lee Sung-ki — best known
for his invention of the synthetic fiber Vinalon — was kidnapped at the
outbreak of the Korean War. He was eventually persuaded to join the
effort by Kim Il-sung who argued that “nuclear development is an
essential project for the unification of the nation.” After the war, Dr.
Lee set up a branch lab at Hamhung, a short distance from the industrial
port city of Hungnam, where some 200 Soviet and foreign advisors worked.
It is now clear, however, that nuclear activities in the Hamhung/Hungnam
area of North Korea began decades earlier when Korea was a Japanese
(Satellite image from Digital Globe)
Following the Tohokuearthquake and tsunami on March 11, 2011, the
Fukushima Number One Power Plant in Japan suffered a series of equipment
failures, a partial meltdown, and the release of radioactive material.
In an article by the former editor of the Japan Times Weekly, Yoichi
Shimatsu described how Japan’s next nuclear accident might become
another Nagasaki, the city that was devastated during WWII by “Fat Man,”
a plutonium atomic bomb. Shimatsu then reminded his readers that Japan
was no stranger to atomic energy:
During the Second World War, the Allies and the Axis competed for an
exotic new energy source — uranium. While the Manhattan Project was
secretly crafting the atomic bomb in New Mexico, Japan opened uranium
mines in Konan, North Korea, which now are the source of Pyongyang’s
nuclear energy program.
During WWII, Konan — now Hungnam, North Korea — was the home of the
largest fertilizer and chemical complex in the Far East. The electric
power required to operate Konan’s electro-chemical and non-ferrous metal
installations — about 400,000 kilowatt per day — was obtained primarily
from two hydro-electric plants some forty miles north of the city. This
region of North Korea, characterized by a mountain chain which rises
abruptly from the Sea of Japan’s coast, slopes gently westward to the
Yalu River, the boundary between North Korea and the northeast region
(Manchuria) of China. Dams on the northwest-flowing Fusen and Chosen
branches of the Yalu River created large storage reservoirs of
year-round generation of more than 500,000 kilowatts. Tunnels carried
the water south from each reservoir through a mountain divide in the
Josen River basin, emptying out into the Sea of Japan at Konan. The
electrical power network in northern Korea during WWII — with a capacity
of more than 1.5 million kilowatts — supplied Konan and the industrial
districts in and around Pyongyang and Seoul. 
Thorium processing plant at Hungnam on August 24, 1950
In addition to electric power, North Korea had enormous uranium
reserves. According to a recent South Korean government report on
Pyongyang’s nuclear and strategic weapons, North Korea is “known to have
about four million tons of uranium  in recoverable deposits,”
although some have called that number exaggerated. Rather than uranium,
the “four million tons” figure may refer to monazite, a mineral
containing thorium and small amounts of uranium oxide. Australia, for
example, exports 10,000 metric tons of monazite per year. According to a
1967 U.S. geological report, North Korean monazite contains 0.15% (or
6,000 tons) of uranium oxide.
In 1931, Kenjiro Kimura and Sakae Shinoda discovered monazite near
P’yongwon in western Korea, just south of the Ch’olsan Mines where it
was first discovered in 1919. Prior to 1940, however, monazite was
mined, not for its thorium or uranium content, but rather for its unique
ability to burn brightly when ignited without burning out. For that
reason, it was widely used in incandescent gas mantles and mining lamps.
But in 1943, during Japan’s search for uranium for use by their nuclear
weapons programs in Tokyo (Ni-go) and Kyoto (F-go), monazite was
discovered in veins by Hideki Tsuda when large crystals were found on
the Ch’olsan Peninsula. Surprisingly, in Tsuda’s 1953 report entitled
“The Monazite Deposits in Korea,” he failed to mention monazite’s
Hungnam, North Korea today
Today, the Ch’olsan Mines provide North Korea with a wide array of rare
earth elements (REE’s) such as terbium, dysprosium, ytterbium, thulium,
and lutetium. REE’s, the most obscure elements in the periodic table,
have hundreds of high-tech applications including critical
military-based technologies such as precision-guided weapons and
night-vision goggles. In 1988, North Korea formed the Korea
International Chemical Joint Venture Company to produce REE’s from
monazite. The Hamhung plant can reportedly process 1,500 tons of
monazite per year from which 400 tons of rare earth metals, as well as
thorium and uranium oxide, can be extracted. According to the U.S.
Geological Survey, the Hamhung plant was reportedly designed to use
solvent extraction technology acquired from China’s Yue Long Chemical
Plant near Shanghai. Production began in 1991.
Atomic Research at Konan
During WWII, General Leslie Groves, the director of the Manhattan
Project, believed that Japan lacked the industrial capacity, scientific
manpower and the “essential raw material” — uranium. “We did not make
any appreciable effort during the war to secure information on atomic
developments in Japan,” Groves wrote in his 1962 memoir Now It Can Be
Told. “First, and most important,” Groves said, “there was not even the
remotest possibility that Japan had enough uranium or uranium ore to
produce the necessary materials for a nuclear weapon.” “In other words,”
Deborah Shapley later wrote in the journal Science, “ [Groves] had far
less intelligence about Japan than he had about Germany.”
Then in 1997, according to AP reporter Richard Benke in a Los Angeles
Times article entitled “New Details Emerge About Japan’s Wartime A-Bomb
Program,” journalist Robert K. Wilcox and researcher Charles W. Stone
discovered U.S. Army documents that referred to “consistent rumors from
the Hungnam (Konan) area” which dealt with the possibility of atomic
research being conducted there. According to one report, the actual
experiments on atomic energy were conducted in Japan but the “practical
application of atomic energy to a bomb or other military use” was
carried out at Konan. “It is unclear,” Benke said, if President Truman
was aware of a Japanese atomic program when he ordered the atomic
bombing of Japan; unlikely, since several Manhattan Project scientists
said in interviews they knew nothing of a Japanese atomic program until
after the war.
Thorium processing plant at Hungnam on August 24, 1950
Ironically, the full extent of nuclear activities in Japanese-occupied
northern Korea first came to light in 1999 following the publication of
a story in the Japanese newspaper Tokyo Shimbun entitled “Atom Bomb
Experiment Undertaken by Former Japanese Armed Forces in Korean
Peninsula Just Prior to the End of the War, According to Secret
Investigation by GHQ.” According to Tokyo Shimbun, a secret, 300-page
GHQ/SCAP report was discovered at a U.S. archive by the Washington D.C.
Bureau of JiJi Press, the Japanese news agency. According to that GHQ
(General Headquarters, U.S. Army) report, Japan tried to develop the
atomic bomb at the Chosen Nitrogen Fertilizer Factory at Konan during
WWII. And on August 12, 1945, Japanese scientists at Konan conducted an
explosive test at sea, shortly before Soviet forces occupied the city,
which, according to eyewitnesses, was “like an A-bomb.” After the war,
the report said, GHQ prohibited research on atomic energy by the
Japanese and impounded uranium compounds hidden at various locations.
When a censored version of that 1947 GHQ/SCAP report appeared three
months earlier in the Atlanta Constitution [with “names, dates, facts
and figures” redacted], the author, David Snell, a young reporter from
Minden, Louisiana, was universally condemned: Dr. Yoshio Nishina, the
head of Japan’s atomic program in Tokyo (Ni-go), called him a liar; the
Russians called him a provocateur; and the U.S. Secretary of War
categorically denied the story. “There was no [atomic] experiments in
Chosen [Korea],” Nishina told the press corps. “However, there was a
fertilizer factory in Konan.”
Snell, an agent with the Criminal Investigation Detachment (CID) of the
U.S. Army’s XXIV Corps (U.S. occupation forces in Korea), said he
obtained his information during an interview in Seoul with the head of
security and counter-intelligence at the Konan plant who was awaiting
repatriation back to Japan. “He was advised, and understood thoroughly,
that he was speaking for publication,” Snell said. Although Snell had
previously been given permission to file stories to his “old paper,” he
was specifically asked to avoid highly controversial stories. So when he
showed his 8-page typewritten manuscript — concerning a Japanese atomic
program at Konan — to the head of U.S. Army intelligence in Seoul, he
was told, “We cannot possibly clear this…We know about the Konan
project, of course.”
bs, secret papers and her atomic bomb plans, and
“dynamite sealed the secrets of the cave,” Snell wrote. But the Russians
arrived quickly before the Japanese scientists could manage to esca
When Snell returned to the States, his story, “Japan Developed Atom
Bomb; Russians Grabbed Scientists,” was published in the Atlanta
Constitution. According to Snell, Japanese scientists had developed and
successfully tested an atomic bomb off the coast of Konan. “With the
advance units of the Russian Army only hours away,” Snell wrote, “the
final scene of this gotterdammerung began.” Japanese destroyed
unfinished atomic bompe.
Those Japanese scientists are now in Moscow, Snell said, “prisoners of
the Russians, tortured by their captors seeking atomic ‘know-how’.”
According to the GHQ/SCAP report, all secret Japanese units were
impounded by the Soviet forces after the occupation of Konan, followed
by joint Soviet-Japanese research.
Verification of Snell’s story came four years after publication of his
front-page headline story in the Atlanta Constitution when U.S.
Intelligence officers revealed the existence of a Soviet atomic research
project at Hungnam, North Korea. According to declassified CIA and U.S.
Air Force reports, B-29’s with the Far East Air Force (FEAF) out of
Okinawa demolished an ore refinery adjacent to the fertilizer factory at
Hungnam, a refinery which was said to produce materials of possible use
in “nuclear fission projects.” According to the Nippon Times, an
English-language Japanese newspaper, U.S. Naval Headquarters in Tokyo
announced its participation in a campaign to destroy North Korean
“industrial facilities with possible links to the Russian atomic
program.” Then in April 1951, General C.J. Bondley, Jr. (Air Force)
awarded Capt. James R. Cole of Green Acres, Maryland with the
Distinguished Flying Cross for “extraordinary achievement” as lead crew
bombardier on the highly successful bombing attack on a “thorium
production plant…at Konan, North Korea.”
Following the attack.
Lt. Gen. George E. Stratemeyer, the FEAF Commander, made note of the
Nippon Times article in his diary. Although the story was released
through the International News Service, it was Stratemeyer’s impression
that “this type of information was of the very highest classification.”
Only later was it learned that North Korea had shipped enormous
quantities of monazite, gold and silver to the Soviet Union in exchanged
for Soviet artillery, ammunition, engineering equipment, aircraft, and
medical supplies in advance of their June 25, 1950 attack on South
Heavy Water at Konan
“North Korea has a Soviet-era heavy water nuclear plant capable of
producing plutonium, a radioactive element essential for making an
atomic bomb. Under a 1994 accord, Pyongyang agreed to scrap the plant in
exchange for light-water reactors built and paid for by the Korean
Peninsula Energy Development Organization, a consortium comprising the
United States, South Korea and Japan.” – Oct. 6, 1997
North Korea was blessed with the majority of the mineral resources on
the Korean peninsula. The value of those mineral reserves are estimated
to be about thirty times greater than South Korea’s. In addition to
thorium and uranium (from monazite), North Korea possesses some 200
minerals of economic value including iron ore, graphite, lead, zinc,
tungsten and magnesite, the ore of magnesium. North Korea’s magnesite
reserves, for example, are the second largest in the world, second only
According to Henry S. Lowenhaupt, a technical sergeant in the U.S.
Army’s Counter Intelligence Corps (CIC), who was assigned to the
Manhattan Project during WWII and later a CIA specialist on nuclear
intelligence, the Russians were set to dismantle and ship the large
magnesium plant at Bitterfeld, German to the Soviet “atomic people” in
1945. They were also “intensely interested” in the Hansgirg magnesium
process plant at Konan when it fell to the Russians at the end of WWII.
Another facet of the problem, “investigated thoroughly,” Lowenhaupt
said, was that the Russians might eventually turn from calcium to
magnesium, just as the Manhattan Project had done. Magnesium, like
calcium, can be used to reduce uranium oxide to pure uranium metal for
use in nuclear weapons.
Fritz J. Hansgirg
The magnesium plant at Konan was designed and built in the 1930’s by a
brilliant Austrian-born chemical engineer by the name of Fritz J.
Hansgirg. Born in Graz, Austria, Hansgirg helped develop a less-costly
method of mass-producing magnesium of extremely high purity. After a
pilot plant at Radentheim, Austria was up and running, Hansgirg’s senior
partner, Emil Winter, the vice-president and director of Pittsburg
Steel, felt he was too old to help build a new magnesium plant on his
own, so he suggested that Hansgirg sell the patent rights to the highest
bidder. So in the fall of 1934, Hansgirg sailed from Austria to
Japanese-occupied Manchuria, and later to Konan, where he lived and
worked for six years before the war.
United States Department of
Energy Office of Hearings and Appeals in 2014 about Fritz Hansgirg
At Konan, Hansgirg helped the Japanese design a magnesium plant, and “in
my spare time,” Hansgirg said, an ingenious method of mass-producing
heavy water. According to the 1999 Tokyo Shimbun article concerning
nuclear research at Konan, the U.S. ordered a thorough investigation —
following publication of David Snell’s article in the Atlanta
Constitution — which concluded that the Chosen Nitrogen Fertilizer Plant
at Konan “produced heavy water jointly with the Japanese Navy” (since
“pre-war times”). While it is not known for certain if the Japanese at
Konan later used Hansgirg’s magnesium process to extract uranium from
monazite or his heavy water process to produce weapons-grade plutonium
from uranium in an atomic pile, it is entirely possible.
When Hansgirg returned to Manchuria from overseas in February 1940, he
found the Japanese to be completely pro-Axis and hostile to all
foreigners, so he left Japan for good, arriving in the United States in
May of that year. There, he struck a deal with Henry Kaiser to help
design a magnesium plant in California. By the start of WWII, Hansgirg
said, the first unit at Kaiser’s Permanente carbothermic magnesium plant
was producing about five tons of magnesium per day, or roughly one-half
of the designed capacity. Shortly after Hansgirg arrived in the U.S.,
however, the FBI began receiving tips that Hansgirg had cavorted with a
high-ranking Nazi official in Manchuria, that he had signed his letters
“Heil Hitler!,” and later expressed joy over Japanese victories and U.S.
defeats. By December 1941, Hansgirg’s FBI file was substantial.
Then on December 16, 1941, about ten days after the Japanese attack on
Pearl Harbor, Hansgirg was arrested by the FBI on a Presidential
Warrant, accused of being “potentially dangerous to the public peace and
safety of the United States,” At the time of his arrest, TIME magazine
said that Hansgirg was “high on the FBI roundup list,” employed at Henry
Kaiser’s magnesium plant in “confidential U.S. defense work.” At once,
rumors spread that the Permanente’s magnesium-making plant might have to
cease. “They were false,” TIME said.
After his arrest, Hansgirg was held temporarily at Santa Clara County
Jail, and later at enemy alien internment camps in San Antonio, Texas
and Stringtown, Oklahoma. When Attorney General Biddle denied permission
for Hansgirg’s wife, Josephine Marie, to visit her husband at
Stringtown, she wrote a lengthy, hand-written letter to Eleanor
Roosevelt, “woman-to-woman,” in which Hansgirg explained that she
refrained from criticizing Hitler for fear it would jeopardize her son.
Although he is “a scientist, not a soldier,” Mrs. Hansgirg explained,
“he is compelled to wear the uniform of the Hitler army.” The letter
ended with an appeal:
If it is within your jurisdiction to aid in reinstating my husband to
his rightful place of usefulness, that his loyalty and integrity may
again be recognized in this country, you may know you will have the
undying gratitude of his wife.
A copy of Mrs. Hansgirg’s letter was forwarded to FBI Director J. Edgar
Hoover who, in turn, forwarded a copy to the Director of the Alien Enemy
Control Unit. Eventually, Hansgirg was paroled into the custody of the
President of Black Mountain College, a small private college in North
Carolina, where he taught physics and chemistry during the war years,
and beyond. Then in July 1949, Hansgirg died “unexpectedly” at the age
of 58. His cause of death is unknown. However, since Fritz Hansgirg had
worked with magnesium for decades, he may have suffered from acute
magnesium ingestion, resulting in Hypermagnesia, an electrolyte
disturbance in which there is an abnormally elevated level of magnesium
in the blood. Hypermagnesia may cause various ailments including CNS
depression, a physiological depression of the central nervous system
that can result in a decreased rate of breathing, decreased heart rate,
and loss of consciousness which can led to coma or death.
1. The spelling of the defector’s name was confirmed by the Korean
Embassy in Tokyo.
2. During WWII, all towns, cities, rivers and mountains were known by
their Japanese names.
3. The figure “four million tons” may refer back to 1964 when North
Korea (with the assistance of China) conducted an extensive nationwide
survey of recoverable uranium reserves.
Citations (in approximate order of publication)
“Business: Hansgirg Detained,” TIME, Dec. 29, 1941.
Air Objective Folder (WWII) – Konan region.
Intelligence Summary of North Korea (ISNK) #12, May 21, 1946.
Snell, David. “Japan Developed Atom Bomb; Russians Grabbed Scientists,”
Atlanta Constitution, Oct. 3, 1946, p. 1.
“Says Soviets Hold Japs Who Turned Out Atomic Bomb,” The Day (New
London, CT), AP, Oct. 3, 1946, p. 1.
Journal of the Elisha Mitchell Scientific Society, Vol. 66, No. 2,
“Citations Given Six Fairchild [Air Force Base] Men,” The
Spokesman-Review, Apr. 28, 1951, p. 6.
Tsuda, Hideo. “The Monazite Deposits in Korea,” Tokyo, Japan: The
Groves, Leslie R. Now It Can Be Told, Harper, 1962.
Overstreet, William C. “Geological Occurrence of Monazite,” Geological
Survey Professional Paper 530, U.S. Government Printing Office, 1967.
Lowenhaupt, Henry S. “Chasing Bitterfeld Calcium,” CIA’s Historical
Review Program, Vol. 17, Spring 1973.
Shapley, Deborah. “Nuclear Weapons History: Japan’s Wartime Bomb
Projects Revealed,” Science, New Series, Vol. 199, No. 4325, (Jan. 13,
“North Korea’s Expanding Nuclear Efforts,” CIA, May 26, 1988.
Benke, Richard. “New Details Emerge About Japan’s Wartime A-Bomb
Program,” Los Angeles Times, June 1, 1997.
“N. Korea Increases Troops by 92,000 Despite Famine,” Deseret News, Oct.
Mobley, Richard A. “North Korea: How Did It Prepare for the 1950
Attack?,” Army History, Spring 2000, p. 5.
“N. Korea Weapons Program Prompts Diplomatic Flurry,” USA Today, AP
(Washington), Oct. 17, 2002.
Kim, Young-sik. “A Physicist Defector’s Account of North Korea’s Nuke
Labs,” Korean Web Weekly, Oct. 2002; kimsoft.com (defunct)
“Defector Leaked Details of N. Korea’s N-Program,” The Daily Yomiuri,
Dec. 18, 2002.
Greenlees, Donald. “How North Korea Fulfilled Its Nuclear Dream,”
International Herald Tribune, Oct. 23, 2006.
Kang Ho-je. “Father of North Korean Nuclear Physics Received the
Appellation ‘People’s Scientist’,” (in Korean) Institute for Modern
Historical Research, No. 111, June 1, 2010.
Hurst, Cindy A. “China’s Ace in the Hole: Rare Earth Elements,” National
Defense University Press: Joint Force Quarterly, Issue 59, 4th Quarter
Yoon, Edward. “Status and Future of the North Korean Mineral Sector,”
University of San Francisco Centre for the Pacific Rim, Jan. 6, 2011.
Shimatsu, Yoichi. “The Next Nagasaki: Nuclear Fears Stalk The World,”
Mar. 19, 2011.
Choi, Kyung-soo. North Korea’s Mining Prospects, NKRI, Aug. 30, 2011.
Ministry for Unification and Institute for Unification Education,”
Understanding North Korea, ROK Government, 2012.
Song Sang-ho, “North Korea Conducts 3rd Nuclear Test,” Korea Herald,
Feb. 12, 2013.
Dougherty, Jill and Benson, Pam. “Material in North Korea’s Nuclear Test
Unclear, Worrying For U.S.,” CNN, Mar. 13, 2013.
Various undisclosed sources including the Tokyo Shimbun article (in
Japanese) and Dr. Fritz J. Hansgirg’s extensive FBI file.
Special thanks to Minoru Kawamoto (A Japanese-American living in Tokyo),
Ken Ricci (an American applied nuclear physicist) and Irek Sabitov (a
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