RISKS FROM RADIATION

EXPOSURE
 Introduction
⚫ Myths created by the film industry
– Spider Man, The Hulk, Teenage Mutant
Ninja Turtles
– Radioactive Material Glows
 Risk
⚫ The statistical probability that
personal injury will result from
some action
– smoking, speeding, extreme sports, ect.
– ionizing radiation exposure
 Radiation and Radioactivity
⚫ Radiation: Energy in transit, either
particulate or electromagnetic in
nature
⚫ Radioactivity: The characteristic of
various materials to emit ionizing
radiation
⚫ Ionization: The removal of electrons
from an atom. The essential
characteristic of high energy
radiations when interacting with
 Elements
An element is the smallest amount of
a substance that still exhibits the
properties of that substance.

Elements are classified by the

number of protons in each atom, and
can be arranged in order in the
Periodic Chart.
 Atoms
Atoms are the building blocks of all
matter, made up of protons and
neutrons and electrons.

Almost all atoms are very stable, but

some may have too much energy
and be radioactive.
 Electromagnetic Waves
Electromagnetic waves are energy waves,
ranging from the low energy radio waves
to the high energy gamma rays.

They have a height (amplitude) and a

length between wave peaks (wave length)
 UNSTABLE atoms emit energy

RF wave infrared visible uv x-ray -ray cosmic

low energy high energy

non-ionizing ionizing radiation

 Ionizing Electromagnetic
Radiation

Ionizing Electromagnetic Radiations do

have enough energy to remove electrons
from atoms, such as:
• X-rays
• Gamma rays
• Neutrons
• Alpha Particles
 Non-Ionizing Electromagnetic
Radiation
Non-Ionizing Electromagnetic
Radiations do not have enough energy to
remove electrons from atoms, such as:
• Ultraviolet Radiation
• Light
• Infrared Radiation
• Microwaves
• Radio Waves
 Non-Ionizing Radiation
Does not have enough energy to remove
electrons from surrounding atoms
 The Atom
Protons 11p
(1.007276 amu)

Neutrons 10n
Electrons (1.008665 amu)
(0.0005486 amu)
Neon-20 2010Ne
(19.992434 amu)
 Alpha Decay

Daughter
Nucleus
Np-237
Th-234 Parent Nucleus

 ++

Ra-228 Am-241
Rn-222 U-238
Th-232 Alpha Particle
Ra-226 (Helium Nucleus)
(4.00147 amu)
 Beta (Negatron) Decay
Daughter
Nucleus


Osmium-187
Calcium-40
Antineutrino

Parent Nucleus
Rhenium-187 
−  −
Potassium-40
Beta Particle
(electron)
 Gamma-Ray Emission

− 
 −

Gamma Ray

Parent Nucleus Daughter Nucleus

Cesium-137 Barium-137m
Molybdenum-99 Technetium-99m
 Positron Decay



Daughter Neutrino
Nucleus
Boron-11   +

Carbon-13 +
-
Positron Particle
Parent Nucleus
(Positive electron)
Carbon-11
Nitrogen-13

Annihilation
Radiation
 X-Ray Production

Electron
X-Ray
Target Nucleus
Tungsten

Anode (+)
Cathode
(-)

X-Rays
 Types of Radiation
  ++ Paper Plastic Lead Concrete

Alpha

− 
 − Beta

Gamma and X-rays




1 n Neutron
0
 Measures of Radioactivity
⚫ Activity: The quantity of radioactive material
present at a given time:
– Curie (Ci) : 3.7x1010
disintegration per
second (dps)
– milliCurie (mCi): 3.7x107 dps
– microCurie (mCi): 3.7x104 dps
– picoCuries (pCi): .037 dps
– Becquerel (Bq): 1 dps
– megaBecquerel (MBq): 1x106 dps
 Half-Life

The time required for the

1200 amount of radioactive material
1000 to decrease by one-half
800
Activity600
400
200
0
New 1 Half- 2 Half- 3 Half- 4 Half-
Life Lives Lives Lives
 Radiation Detection
Gas Filled Detectors
Voltage Source
+ -
Incident Ionizing Radiation

+ + +
+
- Electrical
- - - Current
Anode + Measuring
Device

Cathode -

Air or Other Gas

 Radiation Detection
Scintillation Detectors
Incident Ionizing Radiation
Light Photon Photomultiplier Tube

Pulse
- Measuring
Device

Sodium-Iodide
Crystal Dynode Anode
Photocathode

Optical Window
 MONITORING RADIATION
EXPOSURE

Radiation dosimeters measures radiation dose

to people.
 Radiation is detected with survey meters

Beta, Gamma & X-ray

Alpha Survey Meter
Survey Meter
 Contamination vs Radiation

Radiation and Contamination are often

confused. Radiation is energy, while
contamination is the physical presence of
a radioactive material on something.
So, you may have contamination on your
shoe, but not radiation.
 Radiation Units
⚫ Roentgen: A unit for measuring the
amount of gamma or X rays in air
⚫ Rad: A unit for measuring absorbed
energy from radiation
⚫ Rem: A unit for measuring biological
damage from radiation
 Radiation Effects and Risk
⚫ Exposure: A measure of ionization in air
from x-ray and gamma rays.
– Roentgens, or mR
⚫ Dose: A measure of the energy absorbed in
any material as a radiation passes through it.
– Rads or mradsDose equivalent: A measure of
“risk” associated with a given radiation dose to
a person.
– Rem or mrem
 Radiation Dose by Activity
⚫ Food Irradiation: 100000 rads
⚫ Cancer Radiation Therapy: 6000 rads
⚫ Lethal WB Dose to 50% of Population: 350 rads
⚫ Increase risk of cancer by 1% 12.5 rem
⚫ Maximum Annual Occupational Dose: 5 rem
⚫ Average Annual U.S. Population Dose: 360 mrem
⚫ Average Dose from Radon per year: 200 mrem
⚫ Annual Dose Limit for General Population: 100 mrem
⚫ Dose from a skull x-ray: 8 mrem
⚫ Dose from round-trip flight LA to NY: 2 mrem
IONIZING RADIATION
 Ionizing Radiation
Exposure Effects
⚫ Somatic Effect (Prompt or Delayed)
– Stochastic Effect (Cancer) - probability of effect
occurring increases as doses increases. No Threshold
– Non-Stochastic Effect (Cataracts) - severity of the
effect varies with dosage. Threshold dose
⚫ Teratogenic Effects (Offspring while in-utero)
– mental retardation
– malformations
Alpha Radiation is only a hazard when inside
your body (internal hazard)

Your skin will stop it

can’t penetrate skin
internal hazard

stopped by paper

found in soil,
radon and other
radioactive
materials
Beta Radiation is a Skin, Eye and Internal
Hazard

skin, eye and internal hazard

stopped by plastic

found in natural food, air and water

X and gamma radiation are penetrating
radiation and an EXTERNAL HAZARD.

stopped by lead found in

medical uses

naturally present in soil

and cosmic radiation
Neutron particles have no charge and can
penetrate deep into the body
Biological Effects Known to
Occur at High Doses
⚫ Non-Stochastic Effects:
– Cataracts
– Sterility
– Loss of Hair (Epilation)
– Skin Reddening (Erythema)
– Acute Radiation Syndrome
– Death
⚫ Stochastic Effects:
– Cancer
– Genetic Effects
Ionizing Radiation Exposure
Effects (Con’t)
⚫ Genetic Effects (Future Generations)
– Anemia
– Epilepsy
– Diabetes
– Asthma
 Physical Factors of
Effects
⚫ Acute dose vs. Chronic Dose
⚫ Whole body irradiation vs. partial
body irradiation
 Cancer Facts
What is cancer? - uncontrolled
growth and spread of abnormal cells
⚫ Causes - Many
Risk increases after age 40
⚫ Risk factors
– Personal Habits, Environmental
factors, Occupational hazards
 Cancer Facts (Con’t)
⚫ Prob. of developing cancer in U.S. (from
birth to age 74)
– 40% Male/Female
⚫ Death of cancer victims
– 50% of personnel who develop cancer
will die
⚫ Overall death rate from cancer
– 20%
Cancers frequently linked
to radiation
Breast cancer
Thyroid cancer
Leukemia
Problems with Models

⚫ Cancers are indistinguishable

⚫ Ionizing radiation is not only cause
of cancer
⚫ Long latency period of cancer
⚫ Cannot perform human experiments
⚫ Studies may suggest radiation as the
cause of cancer but cannot identify
 Radiation and Risk
Perceptions and Reality
Public 1 Nuclear Power
2 Motor Vehicles
3 Handguns
4 Smoking
5 Motorcycles
6 Alcoholic Beverages
7 Private Aviation
8 Police Work
9 Pesticides
10 Surgery
11 Fire Fighting
12 Large Construction
13 Hunting
14 Spray Cans
15 Mountain Climbing
 Radiation and Risk:
Perceptions and Reality
Public 16 Bicycles
17 Commercial Aviation
18 Electric Power
19 Swimming
20 Contraceptives
21 Skiing
22 X-Rays
23 High School and College Football
24 Railroads
25 Food Preservatives
26 Food Coloring
27 Power Mowers
28 Prescription Antibiotics
29 Home Appliances
30 Vaccinations
 Radiation and Risk:
Perceptions and Reality
Public 1 Nuclear Power 20 Experts
2 Motor Vehicles 1
3 Handguns 4
4 Smoking 2
5 Motorcycles 6
6 Alcoholic Beverages 3
7 Private Aviation 12
8 Police Work 17
9 Pesticides 8
10 Surgery 5
11 Fire Fighting 18
12 Large Construction 13
13 Hunting 23
14 Spray Cans 26
15 Mountain Climbing 29
 Radiation and Risk:
Perceptions and Reality
Public 16 Bicycles 15 Experts
17 Commercial Aviation 16
18 Electric Power 9
19 Swimming 10
20 Contraceptives 11
21 Skiing 30
22 X-Rays 7
23 High School and College Football 27
24 Railroads 19
25 Food Preservatives 14
26 Food Coloring 21
27 Power Mowers 28
28 Prescription Antibiotics 24
29 Home Appliances 22
30 Vaccinations 25
Days of Life Lost from Various
Risks
Being an unmarried male 3,500
Smoking cigarettes and male 2,250
Heart disease 2,100
Being an unmarried female 1,600
Being 30 percent overweight 1,300
Cancer 980
Being 20 percent overweight 900
Having only an 8th grade education 850
Smoking and being female 800
Being poor 700
Stroke 520
Having a dangerous job 300
Driving a car 207
Pneumonia, Flu 141
Alcohol 130
Accidents in the home 95
Suicide 95
Diabetes 95
 Days of Life Lost from
Various Risks
Being Murdered 90
Having an average risk job 74
Drowning 41
Having a job with radiation exposure 40
Falls 39
Walking down the street 37
Having a safe job 30
Fires and burns 27
Using illegal drugs 18
Poisoning 17
Suffocation 13
Natural Radiation 8
Medical X-Rays 6
Coffee 6
Oral contraceptives 5
Riding a bike 5
Drinking Diet Sodas 2
Radiation from Nuclear Industry 0.02
 Activities which increase risk of
dying by 1 in a Million
Smoking 1.4 Cigarettes Cancer, heart disease
Drinking 0.5 liter of wine Cirrhosis of the liver
Spending 1 hour in a coal mine Black lung disease
Spending 3 hours in a coal mine Accident
Living two days in Boston or New York Air Pollution
Traveling 10 miles by bicycle Accident
Traveling 150 miles by car Accident
Flying 1000 miles by jet Accident
Flying 6000 miles by jet Cancer caused by cosmic radiation
Living two months in Denver Cancer caused by cosmic radiation
Living two months in brick building Cancer caused by natural radiation
One chest x-ray Cancer caused by radiation
Eating 40 Tablespoons of peanut butter Liver cancer caused by aflatoxin B
Living 5 years at site boundary of Cancer caused by radiation
a nuclear plant
Eating 100 charcoal -broiled steaks Cancer from benzopyrene
Living within 5 miles of a nuclear Cancer caused by accidental radiation
reactor for 50 years release
 Years from Your Life
Alcoholic 10.96
Poverty 10.00
Smoking-Male 6.16
No Friends 4.50
Heart Disease 4.40
Cancer 3.42
High Risk Job 3.15
20% Overweight 2.85
H.S. Drop-Out 2.33
Orphan 2.20
Car Accidents 0.57

0 2 4 6 8 10 12
Years
 Days from Your Life
Car Accidents 207
Alcohol 130
Suicide 115
Murder 93
Air Pollution 77
AIDS 55
Energy Conservation 50
Spouse Smoking 50
Radon 30
Drowning 24
Radiation Worker 23
Drinking Water 22
Fire, Burns 20
Natural Radiation 9.3
Natural Hazards 7

0 50 100 150 200 250

Days
 Hours from Your Life
Natural Hazards 168
148.8
Bicycles 144
108
Hazardous Waste 60
48 Anti-Nukes
Peanut Butter 24
21.6
Live Near Nuc Plant 8
3
Nuclear Power 1.2 Government

0 20 40 60 80 100 120 140 160 180

Hours
 Radiation Risk Estimate
⚫ Relative-Risk Coefficient - The fractional
increase in the baseline incidence or
mortality rate for unit dose (4 x 10-4 )
⚫ If 10,000 indiv. received one rem each over
background during their life, 4 additional
deaths would occur of the 2,000 that would
naturally occur
Background and Manufactured Radiation
In the U.S. Contributes
360 mrem per Year

radon - 200

cosmic - 28

diet - 40

terrestrial - 28
 Manufactured sources of radiation
contribute an average of 60 mrem/year

cigarette smoking - 1300 mrem

round trip US by air

medical - 53 mrem 5 mrem per trip

building materials - 3.6 mrem

smoke detectors - 0.0001 mrem

fallout < 1 mrem

Nuclear Power
 Fission
Xenon-144

1 n
0 1 n
0

1 n
Neutron 0

Uranium-235
Plutonium-239

Strontium-90
 Fission Chain Reactions

1 n
0

Neutron
Uranium-235
Plutonium-239
 Pressurized Water Reactor
Control Turbine
Rods Steam Generator
Generator
Reactor
Vessel
Pump

Condensor
Cooling Water

Core Pump

Pump Primary Containment

 Barriers Against Release of
Radiation

Steel
Containment

Fuel Pellets
Concrete
Shield
Building Fuel Rods
Core
Steel
Pressure Vessel
A crayon (without
the tip) is about the Source Energy
size of five
uranium fuel Equivalents
pellets stacked
together

Five uranium 15 Barrels of oil

fuel pellets ..

12 1/2 Tons of wood

have as much energy

available in todays nuclear power 5 Tons of coal
plants as...

85,000 cu ft of natural gas

SIGNS ARE REQUIRED TO NOTIFY EVERYONE OF
THE PRESENCE OF RADIATION
RADON
and
Life
 Uranium Decay Series

Uranium-238 Polonium-218 Polonium-214

4.5E9 y 3.1 m (RaA) 163.7 us (RaC’)

Bismuth-214
Radium-226 19.9 m (RaC)
1600 y

Lead-214 Lead-210
27 m (RaB) 22.3 y (RaD)
Radon-222
3.825 d
 How Radon Gets in the Home?
1. Cracks in Solid Floors

2. Construction Joints 7.
6.

3. Cracks in Walls

4. Gaps in Floors

5. Gaps around Pipes

6. Cavities in Walls 4.

7. The Water Supply 5.

2. 1. 3.
Contribution of Various Sources of
Radiation to Average Annual Dose
Medical Nuclear
X-Rays Medicine
11% Consumer
4% Products (3%)
Internal
11% Other (<1%)
Occupational 0.3%
Terrestrial Fallout <0.3%
8% Nuclear Fuel
Cycle 0.1%
Miscellaneous 0.1%
Cosmic
8%

Radon 55%
 Cancer Death Estimates for
Radon
Deaths
60000 55350
per
Year 50000 Between 7,000 and
30,000 Deaths
40000

30000

20000
14000
10000 7380 7380
2255
0 Motor RADON Drownings Fires Firearm
Vehicle Accidents
Accidents
 Modern Uses of Small
Amounts of Radioactive
Material
⚫ Ophthalmic Glass
or Radiation
⚫ Aerosol (Smoke) Detectors
⚫ Airport Inspection Systems
⚫ Lantern Mantles
⚫ Fluorescent Lamp Starters
⚫ Welding Rods
⚫ Fluid Gauges
⚫ Check Sources
⚫ Uranium Counterweights and Shielding
 Modern Uses of Large
Amounts of Radioactive
Materials or Radiation
⚫ Nuclear Power
⚫ Nuclear Propulsion
⚫ Nuclear Weapons
⚫ Food and Medical Supply Irradiation
⚫ Industrial Radiography
⚫ Scientific Research
⚫ Medical X-Rays
⚫ Nuclear Medicine Services
 Minimize Dose By Good
Practices
⚫ TIME - reduce time of exposure
⚫ DISTANCE - increase distance
⚫ SHIELDING - use shielding
Questions & Comments