Nuclear Radiation
Penetrating Ability of Nuclear Radiation
Units used to measure radiation exposure
• Roentgen – one roentgen is equal to the amount of
radiation that produces 2 x 109 ion pairs when it passes
through 1 cm3 of dry air
• rem – measures radiation damage to tissues; 1 rem
equals the quantity of radiation that does as much tissue
damage as 1 roentgen of X-Rays
• 0.1 rem per year – average background exposure
• 0.5 rem per year – maximum permissible dose
established by US govt.
• 0.05 rem – exposure from a chest x-ray
• 0.02 rem – exposure from a dental x-ray
Radiation Detection
Film badge – relies on
ability of radiation to
develop photographic film
Geiger Counter – measures
ionized gases created by
nuclear radiation
Radioactive Dating
• The half life of radioactive
nuclides is used to determine
the age of objects
• Carbon-14 dating is used to
determine the age of organic
material
• C-14 half-life = 5730 years
• Other isotopes are used to
date older organic material,
rocks, minerals, etc.
Radioactive tracers
• Radioactive isotopes
used to measure the
movement of
substances
• Used in medicine to
diagnose diseases
• Photosynthesis,
enzyme activity, use of
substances by cells
• Movement of
groundwater/pollutants
Cancer Treatment
• Radioactive isotopes
kill rapidly growing
tumor cells
• In some cases, the
source is ingested;
i.e. Iodine-131 used
to treat thyroid cancer
• An external source
(60Co) can be directed
towards the tumor
Nuclear Fission
• A heavy nucleus splits into smaller-more
stable nuclei
• Large amount of energy is released
Chain reaction
Nuclear Power Plants
How nuclear energy works – YouTube
Fukushima Nuclear Reactor Problem Explained
(CNN) - YouTube
Nuclear Fusion
• Small nuclei combine
to form a heavier and
more stable nucleus
• Large amount of
energy is released
• Nuclear fusion was
once thought to be
the ultimate source of
energy;
• Significant obstacles
need to be overcome.
What happens to nuclear waste?
• Nuclear waste material must be stored safely for
hundreds of thousands of years.
• Currently, spent fuel rods are stored on-site at
nuclear power plants. They are stored in pools
of water or eventually in dry casks
• Work has been done on a permanent geological
storage facility – Yucca mountain, Nevada