*ucrl-pres-149818. this work was performed under the auspices of the u.s. department of energy by...

*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


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


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!)



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


Band of Stability


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


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


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


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


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


Penetration of radiationhttp://www.bcm.edu/bodycomplab/Radprimer/radpenetration.htm


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


Additional Uses of Radiation


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


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


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.


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


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


Radioactive contamination

• Measures an amount of activity over a unit of surface area. E.g. 5000 dpm/100 cm2



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


lbl.gov

RADON


RADON EXPOSURE LIMITS


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)


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.


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


peiweifoong.wordpress.com


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


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


Factors affecting biological damageTotal radiation doseDose rateType of radiationArea of body exposedCell sensitivityIndividual sensitivity


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.


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


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)


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


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


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


nrc.gov

Detecting Radiation

Ionizing radiation is capable of knocking electrons off of atoms. Thus we can make instruments capable of “seeing” radiation.


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.


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.


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


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


Skin-photographic film?

When we are exposed to small amount of radiation our skin gets darker; suntan or sunburn.


We can’t detect radiation with our senses so a warning label has been developed and is commonly used.


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.


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


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

*ucrl-pres-149818. this work was performed under the auspices of the u.s. department of energy by...

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