China's nuclear program cost ~$4+ billion in the period 1959 to 1966 which was a huge amount of money in that era, particularly for China whose trade was minuscule.
China assembled huge teams of engineers and scientists and mostly developed nuclear bombs themselves with little outside help because the Russians pulled out long before a weapon had been created.
However, what it demonstrated was that China had huge numbers of competent scientists and engineers and the management of these people and the programs.
China exploded its first nuclear bomb 19 October 1964, five years after the program's inception.
"On December 28, 1966, China successfully conducted its first hydrogen bomb test—only two years and two months after the successful explosion of its first atomic bomb."
The nuclear weapon program heralded China's technological and scientific eveloution and development because it demonstrated the competence of the Chinese in Science, Technology and the successful implementation of bold development plans.
https://thebulletin.org/2024/04/the-short-march-to-chinas-hydrogen-bomb/ Quote: On December 28, 1966, China successfully conducted its first hydrogen bomb test—only two years and two months after the successful explosion of its first atomic bomb. In so doing, China became the fastest among the five initial nuclear-weapon states (the United States, Russia, China, the United Kingdom, and France, collectively known as P5) to pass from its first atomic bomb explosion to a first hydrogen bomb detonation.
There is still very limited knowledge in Western literature about how China built its first H-bomb. Based on newly available information—including Chinese blogs, memoirs, and other publicly available publications—this account reconstructs the history of how China made a breakthrough in understanding hydrogen bomb principles and built its first H-bomb—without foreign help.
Beyond the previously untold story of China’s early exploration of the hydrogen bomb theory, the article also explores in detail the so-called “100 days in Shanghai”—a milestone of China’s hydrogen bomb development—and describes the efforts that led to a series of three nuclear tests that happened in 1966 and 1967 and that are often called “the trilogy” of the H-bomb development in China.
Early explorations
https://thebulletin.org/wp-content/uploads/2024/04/meng-zhaorui.jpg.webp
Raising the Little Red Book in celebration of China’s first atomic bomb test on October 16, 1964. (Photo by Meng Zhaorui)
Moscow’s broken promise
China officially started its nuclear weapon program on January 15, 1955.[1] About two years later, China and the Soviet Union signed the New Defense Technical Accord in Moscow. Under that agreement, Moscow would provide Beijing with a prototype of an atomic bomb model and relevant technical materials. In June 1959, however, as many major relevant facilities in the Chinese nuclear weapon program were at the peak of construction, Soviet-Sino relations deteriorated,[2] and Moscow sent a letter to Beijing formally announcing it would not provide the promised model and data. From the second half of 1959 onward, the Second Ministry of Machine Building Industry—China’s government ministry overseeing the nuclear industry—followed central government policy and relied on the country’s own capabilities to complete the task of developing the atomic bomb.[3]
In early 1960, the weaponeers of the Beijing institute of nuclear weapon research—called the Ninth Institute and placed under the leadership of the Second Ministry[4]—started to explore atomic bomb science and technology. As those weaponeers started working hard on the atomic bomb program, then-Minister of the Second Ministry Liu Jie began considering ways to conduct the nation’s hydrogen bomb development. Before this, he had participated in the negotiation of the 1957 agreement with the Soviet government. In addition to information about the atomic bomb, under the agreement China was also supposed to receive a sample of a boosted nuclear bomb, specifically a “layer-cake” bomb.[5]
Liu understood that the boosted nuclear bomb provided by Moscow would be an atomic bomb, not a hydrogen bomb.[6] He sensed hydrogen bombs and atomic bombs could be very different in principle and structure. (An atomic bomb uses uranium or plutonium and relies on fission, a nuclear reaction that splits an atom or nucleus and releases a large amount of energy; a hydrogen bomb or H-bomb uses fission to trigger a fusion reaction that combines two atomic nuclei to form a single heavier nucleus, releasing a much larger amount of energy.) When the leader of the Soviet expert team was visiting the Second Ministry, Liu took the opportunity to ask him questions about the difference in principle and structure between the hydrogen bomb and the atomic bomb. But none of the responses he received satisfied him.[7] Liu understood that the Soviet Union would not share the hydrogen bomb technology with China. Liu therefore realized that it would take a significant amount of time to make breakthroughs in the theory of the hydrogen bomb and thought the start of this work could not wait until after the success of the first Chinese atomic bomb.