Concept of Nuclear Chemistry and Food Irridiation

CONCEPT OF NUCLEAR CHEMISTRY

Nuclear chemistry is the subfield of chemistry dealing with radioactivity, nuclear processes and nuclear properties. It is the chemistry of radioactive elements which are designed to perform nuclear processes. This includes the corrosion of surfaces and the behavior under conditions of both normal and abnormal operation (such as during an accident).

It includes the study of the chemical effects resulting from the absorption of radiation within living animals, plants, and other materials. The radiation chemistry controls much of radiation biology as radiation has an effect on living things at the molecular scale, to explain it another way the radiation alters the biochemicals within an organism, the alteration of the biomolecules then changes the chemistry which occurs within the organism, this change in biochemistry then can lead to a biological outcome. As a result nuclear chemistry greatly assists the understanding of medical treatments (such as cancer radiotherapy) and has enabled these treatments to improve.

It includes the study of the production and use of radioactive sources for a range of processes. These include radiotherapy in medical applications; the use of radioactive tracers within industry, science and the environment; and the use of radiation to modify materials such as polymers. It also includes the study and use of nuclear processes in non-radioactive areas of human activity.

CONCEPT OF FOOD IRRADIATION

Food Irradiation is the application of radiation, in the form of ionizing energy, to foods. Irradiation is a process by which foods are exposed to as much as 3,000,000 rads of radiation in order to kill insects and bacteria and extend shelf life. These doses are millions times greater than that or an ordinary chest X-ray (which is approximately 20 millirad). Irradiated foods do not become radioactive themselves but some of their cells are altered by the radiation.

The food irradiation process uses three types of ionizing radiation sources:

a)     cobalt-60 gamma sources

b)    electron beam generators

c)     x-ray accelerators

a)     Cobalt 60 Gamma Sources

Cobalt-60 emits ionizing radiation in the form of intense gamma rays. Gamma facilities" store it in stainless steel capsules (like "pencils" of cobalt), in underwater tanks. Cesium-137 is a gamma source that is also used for irradiation. Cesium-137 has a less penetrating gamma beam and a longer half-life, making it more suitable under certain circumstances.

b)     Electron Beam Generators

Electron beam facilities generate e-beams with an electron beam linear accelerator. (It works on the same principle as a television tube.) The electrons are concentrated and accelerated to 99% of the speed of light and energies of up to 10 MeV.

c)     X-Ray Accelerators

X-ray facilities use an electron beam accelerator to target electrons on a metal plate. Although some energy is absorbed, the rest is converted to X-rays. Like gamma rays, X-rays are penetrating, and can be used on food boxes 15 inches thick or more. This allows food to be processed in a shipping container.