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

5.2.5 Safety Precautions – Moving, Using and Storing Radioactive Materials

Why protection is required

• Ionising radiation can cause cell death, genetic mutations and an increased risk of cancer.

  • High doses may produce acute radiation syndrome (cellular damage or death).
  • Low‑dose, long‑term exposure can induce genetic mutations that may be passed to future generations.
  • Both acute and chronic exposures raise the probability of developing cancer.

• These health effects justify strict control when radioactive material is moved, used or stored.

Basic principles of radiation protection (TRI)

The three core ideas – often called the “TRI” rule – underpin every safe‑handling procedure:

1. Time – minimise the time you spend near a source.
2. Distance – increase the distance from the source (radiation intensity follows the inverse‑square law, \(I\propto\frac{1}{r^{2}}\)).
3. Shielding – interpose an appropriate material between you and the source to absorb radiation.

Moving Radioactive Materials

1. Plan the route beforehand; avoid high‑traffic areas and keep the distance travelled as short as possible.
2. Use a shielded container or trolley:

   • Lead‑lined for γ‑/X‑rays.
   • Acrylic (PMMA) for β‑particles.

   The container must display the radiation warning symbol.

3. Carry the source at arm’s length; where possible use remote‑handling tools (tongs, forceps, manipulators) to increase distance.
4. Wear the required personal protective equipment (PPE):

   • Lab coat or protective over‑garment.
   • Gloves suitable for the radionuclide.
   • Personal dosimeter badge.

5. Inform all personnel in the vicinity before moving the source and ensure the area is clear.
6. Example: ^99mTc generators for medical imaging are transported in a sealed, lead‑lined case, with a written route plan and a radiation‑trained courier.

Using Radioactive Materials

• Controlled area – perform work in a designated radiation‑controlled laboratory or hot‑cell; post the radiation hazard symbol at the entrance.
• Shielding – place the source behind the appropriate shield (lead for γ‑rays, acrylic for β‑particles, Plexiglass for α‑particles).
• Collimation – use a lead collimator or aperture to limit the beam to the required area, reducing stray radiation.
• Monitoring – check radiation levels with a Geiger‑Müller counter, scintillation detector or ionisation chamber before, during and after the experiment.
• Emergency preparedness – keep a spill kit, absorbent material and written decontamination instructions readily available.
• Example: In industrial radiography a sealed ^192Ir source is positioned behind a lead collimator; the operator works from a shielded control room and watches the exposure on a video monitor.

Storing Radioactive Materials

1. Store in a locked, lead‑lined cabinet; ventilate if the source emits a gas (e.g., ^85Kr).
2. Maintain an up‑to‑date inventory that records activity, half‑life and date of last inspection; label each container with radionuclide, activity and the hazard symbol.
3. Separate sources by radiation type and activity level to avoid unnecessary shielding and to simplify checks.
4. Keep a minimum clearance of 2 m from walls, shelving or other equipment; use low‑density shelving (e.g., wood) so it does not add extra shielding.
5. Inspect containers regularly for dents, corrosion or broken seals and replace them when required.
6. Example: Hospitals keep ^131I therapy doses in a dedicated, lead‑lined, fire‑rated safe that is accessed only by authorised staff using a key‑card system.

Shielding Materials and Approximate Thicknesses for Typical Energies

Procedural Checklist – Safe Handling of Radioactive Sources

1. Confirm the source’s activity, half‑life and expiry date from the inventory.
2. Verify that the correct shielding, collimation and PPE are available.
3. Perform a pre‑use radiation survey of the work area and record the background level.
4. Use remote‑handling tools wherever possible; keep the source at arm’s length.
5. Record the start and end times of exposure; update personal dosimeter readings after the work.
6. After the experiment, return the source to its shielded container, lock the cabinet and log the action.
7. Carry out a post‑use radiation survey; note any deviations and report them immediately.