Difference Between Radioactive Contamination and Irradiation

The key difference between radioactive contamination and irradiation is that radioactive contamination occurs when there is direct contact with radioactive substances, whereas irradiation occurs when there is indirect exposure to radioactive substances.

Radioactivity is the process in which particles are emitted from nuclei as a result of nuclear instability of a material. These materials are named as radioactive materials. Radioactive contamination and irradiation are two important concepts related to radioactivity in physical chemistry.

CONTENTS

1. Overview and Key Difference
2. What is Radioactive Contamination 
3. What is Irradiation
4. Similarities Between Radioactive Contamination and Irradiation
5. Side by Side Comparison – Radioactive Contamination vs Irradiation in Tabular Form
6. Summary

What is Radioactive Contamination?

Radioactive contamination is the deposition of or the presence of radioactive substances on surfaces where their presence is undesirable. This is also known as radiological contamination. This deposition of radioactive materials can occur on surfaces including solids, liquids or even gases (e.g. presence of radioactive materials within gases). Most importantly, we can identify this radioactive material presence when it is unintended. This particular definition was given by the International Atomic Energy Agency or IAEA.

When there is radioactive contamination, it is a hazard because these radioactive materials can undergo radioactive decay, producing harmful effects such as ionizing radiation (including alpha rays, beta rays and gamma rays) and free neutrons releasing. The degree of hazard can be determined by the concentration of the contaminants, the energy of the emitting radiation, the type of the radiation emitted, the proximity of the contamination to the organs of our body, etc.

There are two major ways of radioactive contamination: natural and manmade radioactive pollution. The natural pollution processes include the radioactive material that occurs throughout nature (in the soil, water, vegetation) and the contamination that can occur through ingestion or inhalation. Manmade pollution can occur following an atmospheric nuclear weapon discharge, nuclear reactor containment breach, nuclear fuel, and fission product releasing.

What is Irradiation?

Irradiation is the process by which an object is exposed to radiation. This exposure to radiation can occur from various sources, including natural sources. However, the term irradiation excludes the exposure to non-ionizing radiation, including IR radiation, visible light, microwaves, etc.

There are different applications of irradiation such as sterilization purposes, medicinal applications including diagnostic imaging, cancer therapy, etc., ion implantation, ion irradiation, application in industrial chemistry for crosslinking of plastic materials, applications in agriculture to protect crops from insects, etc.

What are the Similarities Between Radioactive Contamination and Irradiation?

• The two terms, radioactive contamination and irradiation, are used in physical chemistry.
• Both terms describe the concept of radiation.

What is the Difference Between Radioactive Contamination and Irradiation?

Radioactive contamination is the deposition of or the presence of radioactive substances on surfaces where their presence is undesirable. Irradiation is the process by which an object is exposed to radiation. The key difference between radioactive contamination and irradiation is that radioactive contamination occurs when there is direct contact with radioactive substances, whereas irradiation occurs when there is indirect exposure to radioactive substances.

The following table summarizes the difference between radioactive contamination and irradiation.

Summary – Radioactive Contamination vs Irradiation

Radioactive contamination and irradiation are two important concepts related to radioactivity in physical chemistry. The key difference between radioactive contamination and irradiation is that radioactive contamination occurs when there is direct contact with radioactive substances, whereas the irradiation occurs when there is indirect exposure to radioactive substances.

Reference:

1. “Contamination – Uses and Dangers of Radioactivity – OCR Gateway – GCSE Physics (Single Science) Revision – OCR Gateway” BBC Bitesize. Available here.

Image Courtesy:

2. “Fukushima I by Digital Globe” By Digital Globe – Earthquake and Tsunami damage-Dai Ichi Power Plant, Japan, (CC BY-SA 3.0) via Commons Wikimedia