Applications of radiation chemistry

Radiation chemistry is a branch of chemistry (some say physical chemistry) that studies chemical transformations in materials _____________ (1) to high-energy radiations. Radiation chemistry does not deal with radioactive elements (as radiochemistry does), except to use them as a source of radiation, always physically separated from the irradiated system. Practical applications of radiation chemistry have become_____________ (2), particularly in industry. One specific area of interest has been in radiation modification of polymers for different uses.

Radiation ____________ (3) of polymers is commercially used in the wire and cable industry to improve high temperature performances of _____________ (4) materials as well as in the rubber tire industry. Heat-____________ (5) products (film, tape, tubing, connectors) are most easily made using radiation.

Radiation curing is based on radiation-_____________ (6) polymerization. It produces superior quality products, as compared with thermal and ultraviolet curing, while reducing or eliminating environmental pollution, and lowering overall costs. It is used for surface coating, curing of____________ (7), laminates, and printing, for example.

New emerging applications include radiation treatment of _____________ (8) gases from coal- and oil-fired power plants to remove toxic components, sulphur dioxide, and nitrogen oxide, for purposes of environmental protection. Treated products can be converted into agricultural______________ (9).

Exercise 5. Choose the correct word:

You may be familiar with the sight of a nuclear power plant, such as the one shown in Figure 1. Nuclear fission produces the energy generated by nuclear reactors. This energy is primarily used to generate electricity. A common fuel is fissionable uranium (IV) oxide (UO₂) _____________ (1) in corrosion-resistant fuel rods. The fuel is enriched to contain 3% uranium-235, the amount required to ____________ (2) a chain reaction. Additional rods composed of cadmium or boron control the fission process inside the reactor by absorbing neutrons _____________ (3) during the reaction.

The fission within a nuclear reactor is started by a neutron-____________ (4) source and is stopped by positioning the control rods to absorb virtually all of the neutrons produced in the reaction. The reactor core ____________ (5) a reflector that acts to reflect neutrons back into the core where they will react with the fuel rods. A coolant, usually water, circulates through the reactor core to _____________ (6) the heat generated by the nuclear fission reaction. The hot coolant heats water that is used to power stream-____________ (7) turbines which produce electrical power.

In many ways, the design of a nuclear power plant and that of a fossil fuel burning power plant are very similar. In both cases heat from a reaction is used to generate ___________ (8). The steam is then used to drive turbines that produce electricity. In a typical fossil fuel power plant, the chemical _____________ (9) of coal, oil, or gas generates the heat, whereas in a nuclear power plant, a nuclear fission reaction generates the heat. Because of the hazardous radioactive fuels and fission products present at nuclear power plants, a dense concrete structure is usually built to enclose the reactor. The main purpose of the containment structure is to _____________ (10) personnel and nearby residents from harmful radiation.

Date: 2015-12-18; view: 1400