Topic 4 - Sources of Radiation

Nuclear Weapons

ground zero

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