Radiation Awareness Training

This training course has been partially adaptedfrom slides provided by Steve Backurz, RadiationSafety Officer of The University of New Hampshire

Elayna MellasRadiation Safety Officer

Environmental Health & Safety ManagerClarkson UniversityDowntown Snell 155

Tel: 315-268-6640emellas@clarkson.edu

Overview

What is radiation / radioactivity? What makes radiation harmful? Radiation dose - how much is too much? Background radiation – your exposure can never be zero How are you protected at Clarkson? Emergencies Ordering and receiving radioactive material at Clarkson Questions?

Where DoesRadioactivity Come From?

All matter is made up of atomsAtoms are the smallest component of

an element, comprised of three particles

ProtonsNeutronsElectronsProtons and neutrons are in the central nucleusElectrons orbit the nucleus

What is Radioactivity?

Definition: a collection of unstable atoms that undergo spontaneous transformation that result in new elements.

An atom with an unstable nucleus will “decay” until it becomes a stable atom, emitting radiation as it decays

The “amount” of radioactivity (called activity) is given by the number of nuclear decays that occur per unit time (decays per minute).

The Curie A unit of activity defined by the number

of radioactive decays from a gram of radium

1 Curie (Ci) = 2.22 E12 disintegrations/min (dpm)

Sub-multiples of the Curie: millicurie 1 mCi = 2.22 E9 dpm

microcurie 1 uCi = 2.22 E6 dpm International units: 1 bequerel = 1

disintegration / sec Typical activities used at Clarkson University

are in the Ci to mCi range

RadiationDefinition: energy in the form of particles or

waves

Types of radiation Ionizing: removes electrons from atoms

Particulate (alphas and betas)Waves (gamma and X-rays)

Non-ionizing (electromagnetic): can't remove electrons from atoms

infrared, visible, microwaves, radar, radio waves, lasers

Electromagnetic Spectrum

Radiation wavelength in angstrom units

108 106 104 102 1 10-2 10-4 10-6

X-RaysRadio Infrared Visible

Ultra-VioletLight

Gamma Rays

Cosmic Rays

10-10 10-8 10-6 10-4 10-2 1 102

Photon energy in million electron volts (MeV)

22 4 10

Ionization

Formation of a charged and reactive atom

-

-

-

-

The neutral absorber atom acquires a positive charge

Beta particle

-

Collidingcoulombic fields

Ejected electron

Why is Radiation Harmful?

Radiation deposits small amounts of energy, or "heat" in matter

Alters atoms Damage to cells & DNA causes mutations

and cancer Similar effects may occur from chemicals Much of the resulting damage is from the

production of ions

Radiation DoseHuman dose is measured in rem or millirem1000 mrem = 1 rem1 rem poses the same risk for any type of

ionizing radiation internal or external alpha, beta, gamma, x-ray, or neutron

External radiation exposure measured by dosimetry

Internal radiation exposure measured using bioassay sample analysis

Acute ExposureLarge doses received in a short time period

accidents nuclear war cancer therapy

Short term effects (acute radiation syndrome 150 to 350 rad whole body)

Anorexia NauseaFatigue Vomiting Epilation Diarrhea Hemorrhage Mortality

Acute Effects of Whole Body Exposure on Man

Absorbeddose (Rads) Effect

10,0001,200

600450100

5025

5

Death in a few hoursDeath within daysDeath within weeksLD 50/30Probable recoveryNo observable effectBlood changes definite1st blood change obs

Chronic ExposureDoses received over long periods

Background radiation exposure Occupational radiation exposure

50 rem acute vs 50 rem chronic acute: no time for cell repair chronic: time for cell repair

Average US will receive 20 - 30 rems lifetime Long term effects

Increased risk of cancer, genetic defects 0.07% per rem lifetime exposure Normal risk: 25% (cancer incidence)

Background Radiation Your exposure to radiation can never be zero because

background radiation is always present Natural sources – radon gas Cosmic rays Terrestrial (uranium-235) Healing arts: diagnostic X-rays, radiopharmaceuticals Nuclear weapons tests fallout Research with radioisotopes Consumer products Miscellaneous: air travel, transportation of radioactive

material

Annual Dose from Background Radiation

Total US average dose equivalent = 360 mrem/year

Total exposure Man-made sources

Radon

Internal 11%

Cosmic 8% Terrestrial 6%

Man-Made 18%

55.0%

Medical X-Rays

NuclearMedicine 4%

ConsumerProducts 3%

Other 1%

11

Consumer Products

Tobacco (Po-210) Smoke detectors (Am-241) Welding rods (Th-222) Television (low levels of X-rays) watches & other luminescent products

(tritium or radium) Gas lantern mantles Fiesta ware (Ur-235) Jewelry

Smoke Detectors

Alpha particles from americium-241 (red lines) ionize the air molecules (pink and blue spheres). The ions carry a small current between two electrodes. Smoke particles (brown spheres) attach to ions reducing current and initiate alarm.

Fiesta Ware

Glazed with dye containing uranium

Luminous Watches

Hands and dials contain H-3 or radium that glows in the dark

Nuclear Medicine

X-rays and fluoroscopes are used to look inside the body

Radioactive Material at ClarksonActivities are licensed by the State of New YorkRadiation Safety Committee has responsibility to

review, approve, and oversee activitiesRadiation Safety Officer (RSO) runs programClarkson is required to:

Train individuals that use sources of radiation Train non-radiation workers that work in the

vicinity of radiation sources Monitor and control radiation exposures Maintain signs, labels, postings Manage and properly dispose of radioactive

waste

Research at ClarksonUsing Radiation Sources

Radioactive materials (both open and sealed sources such as S-35, P-32, C-14, H-3, Ra-226, Am-241)

Gas chromatographs (sealed sources) Liquid scintillation counters (sealed

sources for internal standards) X-ray diffraction equipment Electron microscopes

Occupational limits5,000 mrem / year TEDE50,000 mrem / year CDE (any single organ)15,000 mrem / year lens of the eye

Members of public100 mrem / year No more than 2 mrem in any one hour in

unrestricted areas from external sourcesDeclared pregnant females (occupational)

500 mrem / term (evenly distributed)

Standards for Protection Against Radiation

Anticipated ExposuresNon radioactive workers must receive less than

100 mrems / year

Average annual background exposure for U.S. population = 360 mrem / year

State and federal exposure limits for radiation workers = 5000 mrem / year

Anticipated exposures: Less than the minimum detectable dose for film badges (likely less than 10 mrem / month) - essentially zero

Access RestrictionRequired by license and NY regulationsSecurity and control of radioactive material

Restricted area

Controlled area

Unrestricted area

Unrestricted area

Unrestricted area

Posting of Radiation Areas

All radiation areas are posted with warning signs

Use caution when entering and working in a radiation area

If any container is labeled “radioactive” do not disturb

If you have questions or concerns call:Craig Woodworth, radiation safety officer, 268-2391, Room 147 Science Center

Emergency Response

Fire in radioactive areas:Notify Fire Department and RSO, clear the area of people. Remove any seriously wounded persons. Keep your distance

Notify RSO if you suspect:Inhalation, ingestion or other intake of radioactive material

Accidental release of radioactive material into the environment

Radiation Protection BasicsTime: minimize the time that you are in contact

with radioactive material to reduce exposure

Distance: keep your distance. If you double the distance the exposure rate drops by factor of 4

Shielding: Lead, water, or concrete for gamma & X-ray Thick plastic (lucite) for betas

Protective clothing: protects against contamination only - keeps radioactive material off skin and clothes

Radiation Exposure Will NotMake You Radioactive

Radiation: energy in the form of particles and waves

Radioactive material: material that is unstable and emits radiation

Contamination: radioactive material where it is not wanted

Campfire example: burning logs (radioactive material), heat (radiation), burning embers that escape the controlled area (contamination)

Shipping Radioactive Materials

Since the atomic energy industry began over 50 years ago, there has been an excellent record of safety in transportation of nuclear material

Over 4 million packages containing radioactive material are transported annually within the US

To date, there have been no deaths or serious injuries

Ordering & Receiptof Radioactive Materials

Only the RSO is authorized to order radioactive material at Clarkson

When packages are received, call the RSO. He will check for contamination, and deliver to the package to the lab on the same day as receipt

All packages containing radioactive materials must be secured to prevent theft or loss

If any package is damaged, do not handle. Call the RSO immediately and ask the carrier to stay to be checked for contamination

Labels on Packagesof Radioactive Material

Radioactive white I; almost no radiation (0.5 mR/hr or 0.005 mSv/hr) maximum on the surface

Radioactive yellow II; low radiation levels (50 mR/hr or 0.05 mSv/hr) maximum at 1 meter

Radioactive yellow III; higher radiation levels (200 mR/hr or 2 mSv/hr) maximum on surface. 10 mR/hr or .1 mSv/hr maximum at 1 meter.

Labels on Packagesof Radioactive Material

The transport index is the maximum radiation level (mR/hr) at 1 meter from the surface of an undamaged package.

Your Rolein Radiation Protection

Don’t touch or move anything with radioactive material labels.

Report anything that looks out of the ordinary If you are uncertain about what to do, where to

go, requirements, or exposures: Call the people on the emergency number list Call the Radiation Safety Officer (RSO)

Elayna Mellas268-6640

Call 911

Acknowledgements

This training course has been partially adaptedfrom slides provided by Steve Backurz, Radiation Safety Officer of The University of New Hampshire.