*ucrl-pres-149818. this work was performed under the auspices of the u.s. department of energy by...
TRANSCRIPT
*UCRL-PRES-149818. This work was performed under the auspices of the U.S. Department of Energy by the University of California, Lawrence Livermore National Laboratory under Contract No. W-7405-Eng-48. 1
Understanding Radiation Understanding Radiation and Its Effectsand Its Effects
Prepared byBrooke Buddemeier, CHPLLNL Counter Terrorism and Incident Response ProgramLawrence Livermore National Laboratory*[email protected] (925) 423-2627
UCRL-PRES-149818-REV-2UCRL-PRES-149818-REV-2
UCRL-PRES-149818. Understanding Radiation and it’s Effects. 2
Radiation is EnergyRadiation is Energy• The energy is given off by unstable
(radioactive) atoms and some machines.
• For this talk, we will be focusing on ionizing radiation and its health effects.
Ionizing Radiation
Radiation with enough energy to remove an electron from its atom. It is energy in the form of particles or waves, given off by unstable (radioactive) atoms or by accelerated charged particles
UCRL-PRES-149818. Understanding Radiation and it’s Effects. 3
Ionizing vs. Non-ionizingIonizing (can cause cancer)
Non-ionizing
Alpha Solar (visible light)
Beta Radio broadcast
Gamma TV broadcast
X-rays Microwave
Ultraviolet light Heat (infrared)
Fast neutrons Low frequency EMF
MuonsUCRL-PRES-149818. Understanding Radiation and it’s Effects. 4
UCRL-PRES-149818. Understanding Radiation and it’s Effects. 5
Radiation and Radioactive Material Radiation and Radioactive Material are a Natural Part of Our Livesare a Natural Part of Our Lives
• We are constantly exposed to low levels of radiation from outer space, earth, and the healing arts.
• Low levels of naturally occurring radioactive material are in our environment, the food we eat, and in many consumer products.
• Some consumer products also contain small amounts of man-made radioactive material.
• no difference between radiation emitted by natural or man-made sources.
SmokeDetector
Artificial transmutations
When one element is transformed into another element by the bombarding a nucleus with subatomic particles or small nuclei
Fermi lab – Illinois(10.62 square miles!)
UCRL-PRES-149818. Understanding Radiation and it’s Effects. 6
UCRL-PRES-149818. Understanding Radiation and it’s Effects. 7
Unstable Atoms DecayUnstable Atoms Decay The number of “decays” that occur per
unit time in the radioactive material tell us how radioactive it is.
Units include Curies (Ci – 3.7 x 1010 decays per sec – dps = 2.2 x 1012 dpm, and Becquerels (decays per second).
When an unstable atom decays, it transforms into another atom and releases its excess energy in the form of radiation.
Sometimes the new atom is also unstable, creating a “decay chain”
D e c a y serIesgeoinfo.nmt.edu
UCRL-PRES-149818. Understanding Radiation and it’s Effects. 8
Band of Stability
UCRL-PRES-149818. Understanding Radiation and it’s Effects. 9
chemwiki.ucdavis.edu
Band of Stability
cont.
http://www.hasdeu.bz.edu.ro/softuri/fizica/mariana/Atomica/Table/lessons/11nuclear/nuclear.htm UCRL-PRES-149818. Understanding Radiation and it’s Effects. 10
UCRL-PRES-149818. Understanding Radiation and it’s Effects. 11
Forms of RadiationForms of Radiation When unstable atoms
transform, they often eject particles from their nucleus. The most common of these are: Alpha Radiation
High energy, but short range (travels an inch in air, not an external hazard)
Beta RadiationLonger range (10 – 20 feet in air) and can be a skin and eye hazard for high activity beta sources.
Gamma Rays (electromagnetic radiation) Often accompany particle radiation. This “penetrating” radiation is an external hazard and can travel 100s of feet in air.
gamma
gamma
Alpha particle αCharacteristics
Range Shielding Hazards Sources
+2 charge 2 protons 2 neutrons Relatively
large mass
Very short range
1-2 inches in air
Paper Outer
layer of skin
Internal Plutonium Uranium Radium Thorium Americium
UCRL-PRES-149818. Understanding Radiation and it’s Effects. 12
Beta particle βCharacteristics
Range Shielding Hazards Sources
-1 charge Small mass
Short range
About 10’ in air
Plastic safety glasses
Thin metal
Skin and eyes
Can be internal
Radioisotopes
Activation products
Sealed sources
UCRL-PRES-149818. Understanding Radiation and it’s Effects. 13
Gamma Ray γCharacteristics
Range Shielding
Hazards Sources
No charge No mass Similar to x-
rays
Long range
About 1100’ in air
Lead Steel Concret
e
External (whole body)
Can be internal
X-ray Electron
microscopes Sealed
sources Accelerators Nuclear
reactors radioisotope
s
UCRL-PRES-149818. Understanding Radiation and it’s Effects. 14
Neutron particle ηCharacteristics
Range Shielding
Hazards Sources
No charge Found in
nucleus
Extended range
Water plastic
External (whole body)
Fission Reactor
operation Sealed
sources accelerators
UCRL-PRES-149818. Understanding Radiation and it’s Effects. 15
Penetration of radiationhttp://www.bcm.edu/bodycomplab/Radprimer/radpenetration.htm
UCRL-PRES-149818. Understanding Radiation and it’s Effects. 16
Uses for RadiationMedical Uses: Diagnostic X-rays and Diagnostic and Therapeutic Uses of Radioisotopes (ex.I-131)
Academic and Scientific Applications: course work, laboratory demonstrations, experimental research, and a variety of health physics applications. Ex. C-14 dating
UCRL-PRES-149818. Understanding Radiation and it’s Effects. 17
Additional Uses of Radiation
UCRL-PRES-149818. Understanding Radiation and it’s Effects. 18
More Uses of RadiationNuclear power plants -Electricity produced by nuclear fissionIndian Point Nuclear Power Plant: One of New York State's Greatest Assets- aaenvironment.com
UCRL-PRES-149818. Understanding Radiation and it’s Effects. 19
04/18/23 UCRL-PRES-149818. Understanding Radiation and it’s Effects. 20
How Unstable Is It?How Unstable Is It? The “Half-Life” describes how quickly Radioactive
Material decays away with time.
It is the time required for half of the unstable atoms to decay.
Some Examples:Some natural isotopes (like uranium and
thorium) have half-lives that are billions of years,
Most medical isotopes (like Technicium-99m) last only a few days
UCRL-PRES-149818. Understanding Radiation and it’s Effects. 21
Some Isotopes & Their Half LivesSome Isotopes & Their Half Lives
ISOTOPEISOTOPE HALF-HALF-LIFELIFE
APPLICATIONSAPPLICATIONS
Uranium billions of years
Natural uranium is comprised of several different isotopes. When enriched in the isotope of U-235, it’s used to power nuclear reactor or nuclear weapons.
Carbon-14 5730 y Found in nature from cosmic interactions, used to “carbon date” items and as radiolabel for detection of tumors.
Cesium-137 30.2 y Blood irradiators, tumor treatment through external exposure. Also used for industrial radiography.
Hydrogen-3 12.3 y Labeling biological tracers.
Irridium-192 74 d Implants or "seeds" for treatment of cancer. Also used for industrial radiography.
Molybdenum-99 66 h Parent for Tc-99m generator.
Technicium-99m 6 h Brain, heart, liver (gastoenterology), lungs, bones, thyroid, and kidney imaging, regional cerebral blood flow, etc.
UCRL-PRES-149818. Understanding Radiation and it’s Effects. 22
The Amount of Radioactivity is NOT The Amount of Radioactivity is NOT Necessarily Related to SizeNecessarily Related to Size
Specific activity is the amount of radioactivity found in a gram of material.
Radioactive material with long half-lives have low specific activity.
1 gram of Cobalt-60has the same activity as 1800 tons of natural Uranium
UCRL-PRES-149818. Understanding Radiation and it’s Effects. 23
What is a “Dose” of Radiation?What is a “Dose” of Radiation?When radiation’s energy is deposited into
our body’s tissues, that is a dose of radiation.
The more energy deposited into the body, the higher the dose.
Radioactivity units measure the number of nuclear transformations (disintegrations) which occur in a certain time period
Radiation Units – related to doseCurie (Ci) = 37,000,000,000 disintegrations per
second (dps) = 2,200,000,000,000 dp minute
Rem (Roentgen Equivalent to Man) is a unit of measure for radiation dose – estimates biological damage or health risk due to absorption of ionizing radiation
Small doses expressed in mrem = 1/1000 rem.
Sievert = 100 rem
Rad (radiation absorbed dose) & R (Roentgens- measure exposure [ionization] of air by X-rays and gamma rays) are similar units that are often equated to the Rem
UCRL-PRES-149818. Understanding Radiation and it’s Effects. 24
Radioactive contamination
• Measures an amount of activity over a unit of surface area. E.g. 5000 dpm/100 cm2
UCRL-PRES-149818. Understanding Radiation and it’s Effects. 25
UCRL-PRES-149818. Understanding Radiation and it’s Effects. 26
Typical DosesTypical DosesAverage Dose to US Public from All sources 360 mrem/year
Average Dose to US Public From Natural Sources 300 mrem/year
Average Dose to US Public From Medical Uses 53 mrem/year
Coal Burning Power Plant 0.2 mrem/year
Average dose to US Public from Weapons Fallout < 1 mrem/year
Average Dose to US Public From Nuclear Power < 0.1 mrem/year
Occupational Dose Limit for Radiation Workers 5,000 mrem/yr
Coast to coast Airplane roundtrip 5 mrem
Chest X ray 8 mrem
Dental X ray 10 mrem
Head/neck X ray 20 mrem
Shoe Fitting Fluoroscope (not in use now) 170 mrem
CT (head and body) 1,100 mrem
Therapeutic thyroid treatment (dose to the whole body) 7,000 mrem
Average Annual Radiation Exposure
UCRL-PRES-149818. Understanding Radiation and it’s Effects. 27
lbl.gov
RADON
UCRL-PRES-149818. Understanding Radiation and it’s Effects. 28
RADON EXPOSURE LIMITS
UCRL-PRES-149818. Understanding Radiation and it’s Effects. 29
EPA recommends Radon levels should not be more than 4 picocuries per liter of air. A normal house contains ~ 1.5 pCi-L of air (1 pCi/L = 200 mrem/year Effective Dose Equivalent or 1.6 rem/y to the lungs)
UCRL-PRES-149818. Understanding Radiation and it’s Effects. 30
Radiation is a type of energy; Radiation is a type of energy; Contamination is materialContamination is material
Exposure to Radiation will not contaminate you or make you radioactive.
Contamination is Radioactive Material spilled someplace you don’t want it.
Radioactive contamination emits radiation.
Contact with Contamination can contaminate you with the material.
UCRL-PRES-149818. Understanding Radiation and it’s Effects. 31
Our Our BodiesBodies Are Resilient Are Resilient
DNA damage is most important and can lead to cell malfunction or death.
Our body has ~ 60 trillion cells
Each cell takes “a hit” about every 10 seconds, resulting in tens of millions of DNA breaks per cell each year.
BACKGROUND RADIATION causes only a very small fraction of these breaks (~ 5 DNA breaks per cell each year).
Our bodies have a highly efficient DNA repair mechanisms
Ways that radioactive material enters the body
UCRL-PRES-149818. Understanding Radiation and it’s Effects. 32
peiweifoong.wordpress.com
UCRL-PRES-149818. Understanding Radiation and it’s Effects. 33
Types of Exposure & Health EffectsTypes of Exposure & Health Effects Acute Dose
Large radiation dose in a short period of timeLarge doses may result in observable health effects
Early: Nausea & vomitingHair loss, fatigue, & medical complicationsBurns and wounds heal slowly
Examples: medical exposures andaccidental exposure to sealed sources
Chronic DoseRadiation dose received over a long period of time Body more easily repairs damage from chronic
doses Does not usually result in observable effectsExamples: Background Radiation and
Internal DepositionInhalation
UCRL-PRES-149818. Understanding Radiation and it’s Effects. 34
Dividing Cells are the Most Dividing Cells are the Most RadiosensitiveRadiosensitive
Rapidly dividing cells are more susceptible to radiation damage.
Examples of radiosensitive cells are
Blood forming cells
The intestinal lining
Hair follicles
A fetus
This is why the fetus has a exposure limit (over gestation period) of 500 mrem (or 1/10th of the annual adult limit)
Health Effects• Radiation effects on cell chromosomes:
• Somatic effects: observed in the exposed individual
• Heritable effects: observed in future generations of exposed individual
UCRL-PRES-149818. Understanding Radiation and it’s Effects. 35
Factors affecting biological damageTotal radiation doseDose rateType of radiationArea of body exposedCell sensitivityIndividual sensitivity
UCRL-PRES-149818. Understanding Radiation and it’s Effects. 36
At HIGH Doses, We KNOW At HIGH Doses, We KNOW Radiation Causes HarmRadiation Causes Harm
High Dose effects seen in: Radium dial painters Early radiologists Atomic bomb survivors Populations near Chernobyl Medical treatmentsCriticality Accidents
In addition to radiation sickness, increased cancer rates were also evident from high level exposures.
UCRL-PRES-149818. Understanding Radiation and it’s Effects. 37
Effects of ACUTE ExposuresEffects of ACUTE ExposuresDose (Rads*) Effects
25-50First sign of physical effects (drop in white blood cell count)
100Threshold for vomiting (within a few hours of exposure)
320 - 360~ 50% die within 60 days (with minimal supportive care)
480 - 540~50 % die within 60 days(with supportive medical care)
1,000 ~ 100% die within 30 days
* For common external exposures 1 Rad ~ 1Rem = 1,000 mrem
UCRL-PRES-149818. Understanding Radiation and it’s Effects. 38
At LOW Doses, We PRESUME At LOW Doses, We PRESUME Radiation Causes HarmRadiation Causes Harm
No physical effects have been observedAlthough somewhat controversial, this
increased risk of cancer is presumed to be proportional to the dose (no matter how small).
The Bad News: Radiation is a carcinogenand a mutagen
The Good News: Radiation is a very weakcarcinogen and mutagen!
* Similar to those received by Atomic Bomb Survivors (≥10 rem)
UCRL-PRES-149818. Understanding Radiation and it’s Effects. 39
Long-term Effects of RadiationLong-term Effects of RadiationRadiation is assumed to increase one’s
risk of cancer
The “normal” chance of dying of cancer is ~ 23% (~460 out of 2,000).
Each rem is assumed to increase that risk by 0.05% (~1 chance in 2,000).
The occupational radiation dose limit to the whole body is 5 rem/yr
Common activities that cause 1 in a million chances of
dying10 mrem of radiation (cancer)smoking 1.4 cigarettes (lung cancer)eating 40 tablespoons of peanut
butterEating 100 charcoal broiled steaksspending 2 days in NYC (air pollution)driving 40 miles in a car (accident)flying 2500 miles in a jet (accident)canoeing for 6 miles
UCRL-PRES-149818. Understanding Radiation and it’s Effects. 40
Life Expectancy LostSmoking 20 cigs a day 6 yearsOverweight (15%) 2 years Alcohol (US Ave) 1 year All Accidents 207 daysAll Natural Hazards 7 days Occupational dose (300 mrem/yr) 15 days
From IndustryAgriculture 320 daysConstruction 227 dayMining and quarrying 167 daysManufacturing 40 daysOccupational dose (1 rem/yr) 51 days
UCRL-PRES-149818. Understanding Radiation and it’s Effects. 41
Risk-Loss of Life ExpectancyDays of average life expectancy lost due to various
causes
Being an unmarried male 3500
Smoking (1 pack/day) 2250
Being an unmarried female 1600
Being a coal miner 1100
25% overweight 777
Alcohol abuse (U.S. average) 365
Being a construction worker 227
Driving a motor vehicle 207
All industries 60
Radiation: 100 mrem/yr x 70 years 10
Coffee 6UCRL-PRES-149818. Understanding Radiation and it’s Effects. 42
Basic protective measures
UCRL-PRES-149818. Understanding Radiation and it’s Effects. 43
nrc.gov
Detecting Radiation
Ionizing radiation is capable of knocking electrons off of atoms. Thus we can make instruments capable of “seeing” radiation.
UCRL-PRES-149818. Understanding Radiation and it’s Effects. 44
Geiger CountersAn electric current is passed along the walls of a tube. A thin wire passes through the center of the tube (filled with argon) that easily loses electrons when hit with ionizing radiation. When this happens, an electric current can jump through the gas to the wire. This complete the circuit and the electricity causes a loud clicking sound or moves a needle on a dial.
UCRL-PRES-149818. Understanding Radiation and it’s Effects. 45
Scintillation counterTakes advantage of certain substances, such as ZnS, give off light when they are struck by high energy radiation. A photocell senses the flashes of light as radiation strikes and measures the number of decay events per unit time.
UCRL-PRES-149818. Understanding Radiation and it’s Effects. 46
dehs.umn.edu
Radiation affects photographic film similarly to the way light does. But, radiation can penetrate through materials that can stop light. People wear a film badge covered with plastic that prevents light from passing through, but not radiation.gammasonics.com
UCRL-PRES-149818. Understanding Radiation and it’s Effects. 47
DOSIMETER
After use, the film is developed and the extent of darkening relates to amount of radiation exposure
gam
maso
nics.co
m
e-radiography.net
UCRL-PRES-149818. Understanding Radiation and it’s Effects. 48
Skin-photographic film?
When we are exposed to small amount of radiation our skin gets darker; suntan or sunburn.
UCRL-PRES-149818. Understanding Radiation and it’s Effects. 49
We can’t detect radiation with our senses so a warning label has been developed and is commonly used.
UCRL-PRES-149818. Understanding Radiation and it’s Effects. 50
Conclusion (1 of 2):Understanding Radiation and it’s Effects
• Radiation is energy given off by unstable atoms and some machines.
• Radioactive Material contains unstable atoms that give off radiation when they “decay.”
• Contamination is Radioactive Material spread someplace where you don’t want it.
UCRL-PRES-149818. Understanding Radiation and it’s Effects. 51
Conclusion (2 of 2):Understanding Radiation and it’s Effects
• Radiation damages our cell’s DNA, fortunately our body has very efficient repair mechanisms.
• Large acute doses of radiation can cause sickness or even death. The severity of the effects are proportional to the dose.
• All exposures to presumed to increase the risk of cancer. The amount of “increased risk” is proportional to exposure.
Very Small DOSE = Very Small RISK
UCRL-PRES-149818. Understanding Radiation and it’s Effects. 52
ReferencesRisk, DNA, & Dose Effects:RadEFX(sm) Ionizing Radiation Health Effects ForumCopyright © 1994-1997 Baylor College of Medicine, All rights reserved.
http://radefx.bcm.tmc.edu/ionizing/subject/risk/acute.htmWhich cites several references, including:NCRP Report 98 "Guidance on Radiation Received in Space Activities," NCRP, Bethesda (MD)
(1989). Health Effects Model for Nuclear Power Plant Accidence Consequence Analysis. Part 2, Scientific
Basis for Health Effects Models. U.S. Nuclear Regulatory Commission, Report NUREG CR-4214, Rev. 1. Part II. Washington, D.C. NRC: 1989
Smithsonian, V26 No.9. December 1995; “RISK, Part 2: Safeguarding our cells” by James Trefil.
Other Graphics and Info from: Uranium Information CentreMelbourne, Australia
http://www.uic.com.au/index.htm
DOE; Transportation Emergency Preparedness Program (TEPP) http://www.em.doe.gov/otem/program.html