Chemically pure uranium in the solid state is a hard silvery metal, with an atomic number of 92 and atomic weight 238.03. It is the heaviest element so far discovered, having a density of 19.05 g/cm3. It is radioactive, releasing ¦Á, ¦Â and ¦Ã rays when decayed, and forms stable lead in the end. Uranium consists of three radioactive isotopes:238U, 99.275%; 235U, 0.720%; 234U, 0.005%.

In the early 1950s, China had a very weak basis for science and technology as well as for economy, but the State made the strategic decision to develop nuclear industry at the beginning of 1955 in an attempt to make use of the nuclear technology to build a modernized nationale economy, strengthen national defense, fight against nuclear war and safeguard world peace.

To develop nuclear industry, it is necessary to grasp the up-to-date achievements in science and technology, own strong economic forces and industrial basis. And, the development of uranium resources is an important prerequisite for developing nuclear industry independently by a country. When uranium deposits had been found in China, and a foundation had been laid for atomic energy researches, a special central committee headed by the former Premier Zhou Enlai took the direct leadership of the nuclear industry, and solved a number of major issues during its construction and development.

On October 16, 1964, China succeeded in the first atomic bomb explosion experiment.

On June 17, 1967, China's first hydrogen bomb exploded successfully.

In the September of 1971, the first China-made nuclear-powered submarine was successfully launched.

On June 1, 1983, the first nuclear power plant designed and built by China broke ground at Qinshan, Hangzhou Bay, Zhejiang Province, which was completed and started to generate power on December 15, 1991.

Along with the development of nuclear industry, China has now set up a complete research and production system of uranium industry and nuclear fuel circulation, including exploration of uranium resources; production, transformation and condensation of uranium, manufacture of components, processing of spent fuels etc.

Uranium is a widely used nuclear fuel. When bombarded by a neutron, the atomic nucleus of uranium will break into two fission fragments of similar mass, releasing simultaneously a great amount of heat and 2~3 fast neutrons. These neutrons will cause fission of other nuclei, and so forth in continuous fission, forming a chained reaction.

In terms of nuclear fuels, there are no substitutes for it at present. Therefore, it is a unique metal. For a long time in the future, nuclear fission will still be the only way to use nuclear energy. Uranium is the major material for nuclear fission, and so it is the important basis for nuclear industry.

There are two uses for the uranium processed: one is to enter the nuclear reactor as fuel, the other is to be used as material for nuclear explosion.

The most important application of nuclear fission in the world today is to generate electricity with the heat produced in the reactors. Up to the present, a large part of uranium produced has been used by nuclear power plants.

The main advantage of nuclear energy is its high concentration. The heat produced by 1 gram of 235U is 2.8 million times that produced by the same weight of standard coal, i.e., equivalent to the heat burnt by 2.8 tons of standard coal. It is therefore the only new energy resource that can substitute for the widely-used fossil fuels.

The construction cost of a nuclear power plant is high, but as the energy of uranium is highly concentrated, its fuel charges are lower than those of a coal power plant. The fact that the cost of nuclear power is generally lower than that of coal power in the world is attributed to the reasonable use of uranium as the fuel.

The main safety and environment problem of nuclear power lies in its radioactivity, but, through practice of some decades, the present effective measures can guarantee its use as a safe and clean energy.