IGCSE Physics - 5.2.5 Safety Precautions with Radioactive Materials

Objective

Describe how radioactive materials are moved, used and stored in a safe way.

Moving Radioactive Materials

When moving radioactive materials, the primary concern is preventing the spread of contamination and minimizing exposure to radiation. The following precautions are essential:

• Containment: Radioactive materials should be transported in sealed, robust containers designed to prevent leakage. These containers are often made of lead or other dense materials.
• Labeling: Containers must be clearly labeled with the radioactive symbol (trefoil) and information about the radioactive substance, its activity, and the date.
• Shielding: If possible, the container should be shielded with appropriate materials (e.g., lead) to reduce radiation exposure during transport.
• Handling Procedures: Use appropriate tools (e.g., tongs, remote handling equipment) to avoid direct contact with the radioactive material.
• Transportation Routes: Plan transportation routes to minimize exposure to the public and prevent accidental spills.
• Documentation: Maintain detailed records of the material being transported, including its origin, destination, and the person responsible for its transport.

Using Radioactive Materials

Safe use of radioactive materials involves minimizing exposure and preventing contamination. Key safety measures include:

• Shielding: Use appropriate shielding (e.g., lead, concrete) to absorb radiation and reduce exposure to the user and those nearby. The thickness of the shielding required depends on the type and activity of the radioactive material.
• Distance: Maintain as much distance as possible from the radioactive source. Radiation intensity decreases with the square of the distance (inverse square law).
• Time: Minimize the time spent near the radioactive source. The shorter the exposure time, the lower the radiation dose.
• Ventilation: Use fume hoods or other ventilation systems to prevent the inhalation of radioactive particles.
• Personal Protective Equipment (PPE): Wear appropriate PPE, such as gloves, lab coats, and eye protection, to prevent contamination.
• Designated Areas: Use designated areas for handling radioactive materials to control contamination.
• Monitoring: Regularly monitor work areas and equipment for contamination using radiation detectors.

Storing Radioactive Materials

Proper storage of radioactive materials is crucial to prevent accidental exposure and contamination. The following guidelines should be followed:

• Designated Storage Areas: Store radioactive materials in designated, secure areas that are clearly marked with warning signs.
• Shielding: Storage areas should be shielded with appropriate materials (e.g., lead, concrete) to reduce radiation levels.
• Segregation: Separate different types of radioactive materials to prevent contamination in case of a spill.
• Lockable Cabinets: Store radioactive materials in lockable cabinets to prevent unauthorized access.
• Inventory Control: Maintain a detailed inventory of all radioactive materials stored, including their activity and location.
• Regular Inspections: Conduct regular inspections of storage areas to ensure that containers are intact and that there is no evidence of leakage or contamination.
• Waste Segregation: Segregate radioactive waste according to its type and activity.

Radiation Units

Understanding common radiation units is important for safety.

Unit	Description
Becquerel (Bq)	Unit of activity, representing the number of radioactive disintegrations per second.
Curie (Ci)	Older unit of activity. 1 Ci = $3.7 \times 10^{10}$ Bq
Roentgen (R)	Unit of exposure to gamma and X-ray radiation.
Sievert (Sv)	Unit of effective dose, representing the biological effect of radiation.
Rem (rem)	Older unit of dose. 1 Sv = 100 rem