Topic 4 - Sources of Radiation

Nuclear Weapons

Nuclear Weapons

• Atmospheric testing caused largest environmental release of anthropogenic nuclides
• Radioactive debris consists of
  • Large Particles (fallout in hrs)
  • Smaller particles, in troposphere, behave like aerosols (days)
  • Final fraction, in stratosphere, deposit world-wide (months)
• <100 kt yield - troposphere
• > 500 kt  yield- all stratosphere

Radioactive Fallout

• Stratospheric Deposition
  • circulates for years
  • deposited pole to pole
• Key Nuclides
  • ⁹⁰Sr
  • ⁸⁹Sr
  • ¹³⁷Cs
  • ¹⁴C
  • Pu
  • I
  • Miscellaneous

Other Sources of Exposure

• Radium
• U & Th in Ceramics & Glass
• Depleted U projectiles
• Th in Gas Mantles
• Th in Welding Rods
• Isotopes in Research & Industry
• ²⁴¹Am in Smoke Detectors
• Thermoelectric Generators
• Isotopes in Medicine

Why do YOU care?

• Natural and anthropogenic sources are present everywhere
• Contribute to the radiation field you live in and/or measure
• May need to distinguish contributions
• Decommissioning
• Site characterization
• Dose reconstruction