Application of nuclear techniques
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In China, the application of nuclear techniques has experienced three historical periods as a whole, i.e. pioneering in 50s, applied development in 60s, and all-round development since 80s. Thanks to "reform and opening to the outside world", great progress has been made in all applications, particularly, entering 90s, the number of industrial electron accelerators is doubled almost every three years. The actual loading of industrial Co sources was one time more in 1998 as compared with that in 1994; China is internationally praised as a country for its fastest growth in this aspect.

The isotope and radiation techniques have become a newly established high-tech industry in the developed countries. They are penetrating from traditional application into the forefront and a new field of modern science and technology such as life science and material science, which are forming a more up-to-date cross-over discipline, the economic and social benefits achieved up to ten billions even 100 billions US$.

In medical applications, more than 40 units are engaged in R&D and production of radiopharmaceuticals. Statistics show that the species reaches over 100, and annual output value 0.22 billion yuan RMB, the number of medical clients over 700.

With the rapid evolution of modern nuclear medicine, the application of advanced nuclear medical devices (such as SPECT and PET) the radiopharmaceuticals for diagnosis and treatment of difficult and complicated cases, e.g. tumor, has developed at a quick pace. In respect of radiography sources, Mo-Te generator is available every week.

In industrial applications, these are two kinds of radiation sources often used in industry, i.e. γ-radiator and electron accelerator. In China, there are 48 commercial radiation facilities, the designed source-loading capacity over 300,000 for each, they are distributed in 41cities and counties all over 20 provinces, municipalities, and autonomous regions, the designed source-loading capacity totaling 29.10 million Ci; in addition, there are 75 radiation source including 2 Cs source devices facilities, the designed source loading capacity below 300,000 Ci for each, which implies that the different kinds of radiation source facilities totals 123, and the practical source loading approximately 13 million Ci, and increase of 117% as compared to the figure in 1994. As for the electron accelerator, the facility with power over 5 kW is doubled every three years since 1992, there are 45 sets, including 24 imports, the power totaling 2005 kW, in which 22 sets are used to produce heat shrink material (including 10 sets for special purposes), 34 sets to produce wire and cable (including 23 sets for special purposes); furthermore, there are 8 sets of industrial accelerators with power below 5 kW in research institutes mainly for producing PE foaming, polymer grafting and coating solidification.

In China, the industrialized radiation processing started with radiation chemistry. According to the preliminary statistics, in 1998, the annual output value of radiation-cross-linked wire and cable, and heat shrink material was 0.7 billion yuan RMB separately; the annual output value of 6 plants engaging in radiation-produced low-temperature binder totals over 30 million yuan RMB.

From the application point of view, the nuclear technology may be summarized into three basic functions, i.e. functions of information acquisition, material modification, and energy release.

1. Function of information acquisition

In nuclear techniques, by using nuclear characteristics of isotopes (radioactivity decay and mass difference), and physical, chemical and biological effects of ionizing radiation, the existence and state of material can be detected, and their movement and behavior traced. So that information of material is acquired.

Nuclear technique as a sensitive means of detecting information can hardly be replaced by other sensing means (such as sound, heat, light, force, moisture, gas and chemical), therefore it holds a very important position among techniques for information acquisition.

2. Function of material modification or processing

Nuclear technique, as a means of material modification or processing, is realized through physical, chemical and biological effects, which are created by interaction between ionizing radiation and the material. Due to the changes in structure or composition of material under the effective role of ionizing radiation, the ordinary substance or material may be transformed into a entirely new substance, which does not exist in nature or is a new-type material with extraordinary properties.

This function has been used in some practices, e.g. the ionizing radiation used to selectively destroy the cancer cells (radiotherapy), induce mutation of plant strains (radiation breeding), sterilize insects and pests (insect and pest radiation sterilization), kill insects and pests in agricultural products (radiation insect and pest killing), which have already achieved distinctive effects. The function of this technique is also reflected in the radiation processing of the organic high-molecular material (high-molecular radiation cross-linking) and solid-material radiation modification (semiconductor and metal modification). These materials have made their important contributions in industrial production and national defense, created remarkable economic benefits. The potentialities of nuclear techniques for production and processing are enormous, they are still needed for further exploration. Along with the development of different kinds of ionizing radiation, beam intensity and beam energy, this function can be found in more and more fields of application.

3. Function of energy release

Energy release mostly implies the energy produced by nuclear fission of heavy-element material under the condition of neutron bombardment. This energy release of nuclear fission is now extensively used in civil projects for generation of electric power or heating besides nuclear weapon. Another kind of energy release is the energy of light-element nuclear fusion. This energy, though fully demonstrated in bombardment of hydrogen bomb, remains at the development stage, when used to generate electric power in the form of controlled nuclear fusion energy. It is believed that the controlled release of fusion energy will provide unlimited energy, since fusion fuels are nearly "inexhaustible". Additionally, different kind of ionizing radiation itself is a form of special energy with high-energy effectiveness and highly concentrated energy density, which is emitted through radioisotope decay. This decay energy can be used as a highly-effective energy source for mini-lighter of spontaneous luminescence (such as Ne lamp), isotope power generator or heat source, and for radiation processing.