816 underground nuclear engineering

816 underground nuclear engineering

In 1967, a mysterious special forces unit secretly entered the deep mountain of Fuling to excavate the underground nuclear plant. The Chongqing 816 underground nuclear plant built to serve the production of atomic bombs is "the world's first man-made cavern", with a total investment of 740 million yuan. By the time the project was stopped in 1984, 85% of the construction work and 60% of the installation work had been completed. In April 2002, the Commission of science, technology and industry for National Defense issued a declassification order: 816 underground giant nuclear war industrial cave meets the world again. In 2010, "project 816" was opened to tourists as a scenic spot for the first time. Subsequently, in order to further improve and upgrade the facilities of the scenic spot, the Fuling District government carried out a one-year closed construction of the "816 project" in 2015. On September 25, 2016, after a year's rest, he opened the door again.

On January 27, 2018, 816 project (816 scenic spot) was selected into the "China industrial heritage protection list".

On July 29, 2019, it was rated as national AAAA tourist attraction.

Construction history

historical background

The Sino Soviet split in 1958, and the Beibu Gulf incident broke out on August 2, 1964. A fierce battle broke out between the US destroyer Max and the Vietnamese Navy torpedoes, which spread to southern China. Later, Mao Zedong pointed out twice at the meeting of the Secretariat of the CPC Central Committee that China's economic lifelines are concentrated in big cities and coastal areas, which is not conducive to war preparation, and all provinces should establish their own strategic rear areas.

Site selection approval

In the 1960s, the state decided to build a nuclear plant in the southwest of the rear area. After many investigations and demonstrations, the relevant departments selected a site in Baitao Town, Fuling, Chongqing. In order to keep secret, the place name of Bai Tao disappeared from the map.

In 1966, Zhou Enlai approved the construction of China's second nuclear material industrial base in Baitao, Fuling, namely, the nuclear reactor and chemical reprocessing project of "three line construction", which is an underground nuclear factory providing nuclear materials for the manufacture of atomic bombs. The 8342 unit of the Central Military Commission is responsible for the main construction task. This is classified as a top secret military secret.

Secret construction

At the beginning of the construction of the factory, 816 project was regarded as a highly confidential military industrial unit of the state. At that time, 816 was known as "state-owned Jianxin Chemical Machinery Factory". There was a regiment in charge of security in the factory, and the construction site was never allowed to leak. The correspondence address could only be written in box 4513 of Chongqing city. The family members of the workers could not enter the factory, and the workers could only go home to visit their relatives.

816 project is located in Baitao town of Fuling, a small town with only a few thousand people on the edge of Wujiang River. In order to keep secret, all people with "problems" will move out, and the place name of Baitao will disappear from the map. In February 1967, three regiments affiliated to the 54th division of the Engineering Corps ("Cultural Revolution" code "8342 unit") entered Sichuan to undertake the construction task of the 816 project of the third southwest line. In 1970, a regiment of the 54th division that participated in the war against the United States and Aid Vietnam and a regiment that stayed in Jiuquan base were all returned. The Ministry of nuclear energy industry of the people's Republic of China has also successively sent three construction companies, whose main tasks are to build bridges, pave roads, build factories and residential areas. The number of migrant workers deployed by Fuling District and county is about 10000, and the number of talents recruited from the whole country and top technicians transferred from old factories is nearly 10000. In this little-known gully, nearly 60000 people gathered.

In 1975, the 54th division completed the tunnel construction task and was ordered to evacuate Bai Tao.

Closed down

In February 1984, due to the changes in the international situation, the 816 project was closed and never officially put into production. Later, a small part of the "816 project" was used as a material warehouse by Jianfeng Chemical Plant of China nuclear industry.

Most of the works had been completed when the construction was stopped. When receiving the instruction to postpone the construction in 1982, the 816 plant had completed 85% of the construction works, 60% of the installation works, and the total investment reached 740 million yuan.

Declassification and opening

On April 8, 2002, the Commission of science, technology and industry for national defense agreed to declassify the 816 project with the document No.

After several years of preparation, at the end of April 2010, as the world's largest man-made cave and China's only declassified nuclear reactor, part of the 816 cave project began to become a tourism project

.

It was opened as a scenic spot in April 2010.

On September 25, 2016, after a year's rest, he opened the door again.

Nowadays, the scenic spots open to the outside world make comprehensive use of acousto-optic effects, and simulate the restoration of some of the original functions of the nuclear project. For example, 104 hall was once the site of China's first atomic power plant, where the scene of steam turbine power generation was simulated.

At the same time, the historical background, site selection, project construction, decryption and opening-up of 816 project are also displayed in the scenic area in the form of pictures and objects.

"In order not to destroy the original structure of the cave, and let tourists feel more comprehensive experience brought by vision and hearing on the basis of the original ecology, we use the acousto-optic effect." Zhang Yuanjun, deputy general manager of Chongqing Jianfeng Industrial Group Co., Ltd., who participated in the "816 project", told reporters. "We built a glass corridor at the bottom of the pot on the third floor of area 101 to simulate the green light reflected by nuclear materials. Tourists can walk through the top of the pot to experience the deposition of the pot for 50 years. In the 816 project with a total length of about 3 kilometers and a water storage capacity of 24000 cubic meters In the water diversion tunnel of the water supply system, we have arranged blue and red ring light belts to let tourists see the whole water supply system clearly. " Zhang Yuanjun said. "The areas 101 and 104 that we opened before are just the tip of the iceberg of the whole project. This reconstruction project will open new areas 105, 221 and 229, and the whole tour time will be increased from the original one hour to about three hours." Liu Kangzhong, member of the Standing Committee of the CPC Fuling District Committee and deputy district chief of Chongqing, told China News Agency, "we need to build the 816 project into a comprehensive project integrating Nuclear Science Popularization Center, patriotic education base and interactive experience center."

In April 2010, Chongqing Fuling 816 military cave, known as "the world's largest artificial cave", was opened to the public as a tourist attraction for the first time. The project was started in 1967. In the early stage, the engineers were responsible for digging holes. After 1975, the 816 factory construction team was responsible for the construction of the factory building, with a total manpower of more than 60000 people. Due to the change of international situation and the need of national economic strategy adjustment, the project was shut down in 1984. It was declassified in April 2002. It was opened as a scenic spot in April 2010.

architectural composition

816 project has a total construction area of 104000 square meters. There are 18 large caverns, 130 roads, pilot tunnels, adits, tunnels and shafts. The axial line length of all caverns is more than 20 kilometers. Among them, the largest cavern is 79.6 meters high, the side wall excavation span is 25.2 meters, the vault span is 31.2 meters, and the area is 13000 square meters. In 1978, the engineering design of "building in the cave, hole in the building, river in the cave" won the collective award of national science and technology conference.

Cave structure

Mountain scenery

The military cave is close to Wujiang River and back to Wuling Mountain. There is a huge underground nuclear power plant hidden under the hill with high mountains and dense forests. But from the appearance, there is no trace of the project except the tall exhaust chimney.

Internal connection

In order to build the project, the whole mountain was hollowed out. The cave hall has nine floors, with a height of 79.6 meters and a total length of 24 kilometers. There are 1.51 million cubic meters of stonework excavated in the construction of the cave. If the stone slag is built into a one meter square stone wall, it can be as long as 1500 kilometers. There are 19 large and small openings around the mountain. According to different plans, there should be people's entrances and exits, car access tunnels, drainage tunnels, drainage ditches and warehouses. There are 18 large and small caves, and more than 130 roads, pilot tunnels, branch tunnels and so on. By the end of the 1980s, 85% of the construction work and 60% of the installation work had been completed, with a total investment of 740 million yuan. When the project stopped, some openings were sealed, so no one knew the exact number of openings.

nuclear reactor

Main workshop

The largest cavern in the nuclear cavern is the main reactor building. The excavation span of the side wall is 25.2 meters, the vault span is 31.2 meters, the height is 69 meters, and the total area is 13000 square meters. The nuclear reactor hall runs from three floors to nine floors.

Reaction Hall

Located in the 8-story nuclear reactor hall, the 20-30-meter-high hall, the support part of the reactor in that year is still preserved. The support made of nearly 1-meter-wide "I" shaped steel is wound into a square shape. Under the support, the round sockets of the large process pipes are dense, with 1984 process pipes. The radiation protection ditch more than 1-meter wide is covered with barite sand transported from Yunnan, empty The top of the hall is full of round holes, each about 10 cm in diameter. There are two layers of steel corridors on the walls around the reaction hall, and the milky white paint walls are still shining. The heavy iron gate is two inches thick.

Reaction pot

The bottom of the nuclear reactor hall, which is the third floor of the 816 nuclear war cave, passes through a narrow corridor

Chinese PinYin : Di Xia He Gong Cheng