Radiation
Neutral Atom
(Non-radioactive)
• Electrons (-) orbit nucleus (the center) consisting
of protons (+) and neutrons
• Has same number of electrons (-) & protons (+)
• Atomic number (number of protons) determines
element
Radiation
• A Radioactive atom emits radioactivity because
the nucleus has too much energy
• The nucleus breaks down in an attempt to reach
a stable state
• That excess energy may be in the form of
particles or waves
Ionizing Radiation
• In Ionization the electron (-) is removed
resulting in an ion pair
– Capable of causing bodily damage
• Ionized atom in human DNA may be altered,
causing cell death or mutation
Ionizing Radiation
• Ionizing Radiation
• Non-Ionizing Radiation
– Visible light/heat/radio waves/microwaves
Natural Background Radiation
• Comes from three primary sources:
– cosmic radiation
– solar radiation
– external terrestrial sources
Medical Uses
• One of it’s main uses is to sterilize
• Electrons, X rays, gamma rays or atomic ions
may be used in radiation therapy to treat
malignant tumors (cancer) by killing cancerous
cells
Industrial Uses
• Radiography by means of gamma or x rays to
determine thickness gauges
• Radioactive tracers for industry, makes it
possible to find a hole in a tube
• Used to avoid the build-up of static electricity in
production of paper, plastics, synthetic textiles
• Smoke detectors
Radiation Exposures
Radiation Exposures
ALPHA RADIATION
• Particle travels short distance in air (1-2”)
• Inhalation/Ingestion can be harmful/deadly
• Paper/skin can stop it’s penetration
2 Protons
2 Neutrons
BETA RADIATION
• Particle travels several feet (Hi-Beta- up to 30’)
• Can penetrate eyes, skin, causing burns
• Clothing & turnout gear can absorb most Beta
radiation
GAMMA RADIATION
• Energy waves that travel endlessly
• Travels at the speed of light
• Lead, concrete, iron, dense materials needed
for protection
X-RAY RADIATION
• Energy as a result of excess energy from the
emission of electrons (-)
• Lead, concrete, iron can be used as protection
NEUTRON RADIATION
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Neutrons ejected from the nucleus
No Charge (it’s neutral)
Does not directly cause ionization
Unstable and decays by Beta emission
Neutron particle can:
– Be absorbed (if it’s slow moving)
– Collide resulting in instability (if it’s fast moving)
• Shields better with materials that have a high hydrogen
content; water, plastic, boron, paraffin, concrete
Types of Radiation
200’ plus
200’ plus
up to 10’
Paper
Paper
1-2”
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Units of Measurement
• ROENTGEN
– Amount of exposure to X-ray or gamma only
• RAD (Radiation Absorbed Dose)
– Amount of energy deposited in human tissue
• REM (Roentgen Equivalent Man)
– Amount of biological damage
• System Internationale (SI):
– Curie (Ci) or Becquerel (bq)- Radiation given off
– Gray (Gy)- Amount of energy deposited in human tissue
– Sievert (Sv)- Amount of biological damage
Units of Measurement
R
(rem)
High
mR (millirem)
µR
(microrem)
low
• 1 rem =
1000 millirems
• 1 millirem = 1000 microrems
Radiation
Dose and Rate
• Rate:
– The rate at which radiation energy is deposited
– Measured in microrem, millirem or rem per hour
– (similar to MPH on a vehicle)
• Dose:
– Total Amount of radiation deposited in the body
– Measured in microrem, millirem or rem
– (similar to total miles on a vehicle)
Exposure vs Contamination
Exposure
Occurs in direct contact with the body or
when taken into the body
Contamination
Occurs when the material clings to or
saturates clothing, or parts of your body
Emergency Exposure Guidelines
EPA has established guidelines for controlling
emergency exposures:
Guidelines for Control of Emergency Exposures
Dose Limit (rem)
Activity Performed
Condition
5 rem
All
U.S. yearly dose limit
10 rem
Protect Property
Where a lower dose limit is not
practicable
25 rem
Lifesaving or protection of large Where a lower dose limit is not
populations
practicable
>25 rem
Lifesaving or protection of large On a voluntary basis to personnel
populations
fully aware of the risks involved
Source EPA 400-R-92-001
Biological Effects
• Acute
– Immediate effects due to large
doses over a short period
– Massive cell damage
• Chronic
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Smaller doses repeated over time
No immediate effects
Reproductive or metabolic damage
Mutation of unborn
Death over a period of time
Radiation Damage Factors
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Types of Radiation
Duration of Exposure
Intensity of Radiation
Portion of body receiving dose
Individual characteristics:
– Gender
– Age
– Health
Radiation Effects
DOSE
• 0 – 25 rem
• 25 – 50 rem
• 50 -100 rem
• 100 – 300 rem
• 340 rem
• 500 rem
• > 600 rem
SYMPTOM
None
Mostly none
Bone marrow damage, decrease
in red/white blood cells
Mild/severe nausea, infection,
recovery probable
Half will die, poor care
Half will die, good care
Death expected
Radiation-Warning Labels
3 different labels may be used:
Placard required
– Radioactive White-I
Radioactive
White-I
(nmt 0.5 mr)
– Radioactive Yellow-II
Radioactive
Yellow-II
over 1000 lbs
Radioactive
Yellow-III
Any Amount
(nmt 50 mr)
– Radioactive Yellow-III
over 1000 lbs
(nmt 200 mr)
Placard Placement
When required, they must appear on all four sides of transport vehicle
UN Identification Number
• UN ID number may appear close to placard
• Orange sign with black lettering
704 Diamond
• Located at Fixed Facilities
Packaging
Self Protection
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Time, Distance & Shielding
Minimize time in radiation area
Maximize distance
Use available shielding
Inverse square law
½ the distance = 4x the dose
Radiation
• Radiation is colorless odorless, and tasteless
only a meter can detect the presence of
radiation
• Explosions may be a means of dispersing
radiation
• Radiation meters should be deployed at ALL
reports of explosions
• When checking for the presence of radiation,
hold meters remote from the body (at arm’s
length), to avoid exposure to internal organs
Signs and Symptoms of
Radiation Exposure
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Skin Burns
Nausea
Weakness
Respiratory Distress
Chernobyl
April 26, 1986
• Firefighters exposed to steam cloud
• Within 15 minutes experienced symptoms
• 1hr 30 minutes later
– firefighters were too weak to lift hose
• 28 Firefighters died
• Officially 31 people
• Unofficially 25,000 workers that were sent to clean
up the site have since died
Chernobyl
500 microrems - 3 rems
Chernobyl Contamination
NYC Nuclear Device Mortality
Powerpoint prepared by:
Capt Carlos Vazquez
HazMat Operations