Proprietary and Confidential

Basics of RadiationBasics of Radiation

Terry Romanko

Technical Director

TestAmerica St. Louis

Aug 5, 2015

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What is Radioactive Material?

• Any material containing unstable atoms that emit radiation.

• Radioactivity is the process of unstable atoms becoming stable. This is done by emitting radiation, or giving off energy. This process is referred to as radioactive decay.

“Is it Radioactive?”

• Many consumer products contain radioactivity (In fact the question is not “Is it radioactive?”, but “How much does it contain?”~ Fiesta Ware (and other glazed

items)~ Bathroom tile~ Granite countertops~ Cigarettes/tobacco~ Brazil nuts~ Potassium salt (table and

water softener~ Incandescent gas lantern

mantles~ Many more:

(http://www.orau.org/ptp/collection/consumer%20products/consumer.htm)

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Common terms

• Radioactive Half-life: the time it takes for one half of the unstable atoms present to decay. Example -~ Ni-65 = 2.52 hours~ K-40 = 1.28x109 years

• Radioactive contamination: radioactive material that is uncontained and in an unwanted place.~ It is important to note that exposure to radiation does not

necessarily result in contamination of the worker. Radiation is energy; contamination is a material. When properly contained, radiation may still be an external dose hazard but not a contamination hazard.

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Common terms (cont.)

• Ionizing radiation: is energy emitted from radioactive atoms, and some devices, that cause ionization.

• Non-ionizing radiation: Electromagnetic radiation that doesn’t have enough energy to ionize an atom.~ Examples are radar waves, microwaves, and

even visible light.

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Common terms (cont.)

• Source Material: The NRC’s definition of source material means Uranium (U) or Thorium (Th), or any combination thereof, in any physical or chemical form or ores which contain by weight 1/20th of 1% (0.05%) or more of U, Th, or any combination thereof.

• Unimportant Quantities of Source Material: Any person is exempt from licensing regulations and requirements to the extent that such person receives, possesses, uses, transfers, or delivers source material in any chemical mixture in which the source material is by weight less than 1/20 th of 1%, and that said person does not refine or process such material.

• Byproduct Material: The tailings or wastes produced by the extraction or concentration of U or Th from any ore processed primarily for its source material content.

• NORM: or Naturally Occurring Radioactive Materials, consist of materials that are found in the environment, such as uranium, thorium, and potassium, and any of their decay products, such as radium and radon. These natural radioactive elements are present in very low concentrations in earth’s crust and are brought to the surface through activities such as mining and oil & gas exploration.

• TENORM: or Technologically Enhanced Naturally Occurring Materials, means NORM whose radionuclide concentrations are increased by or as a result of human practices. A good example of TENORM is coal ash produced from coal firing in power plants.

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The Four Basic Types of Ionizing Radiation

• Alpha radiation• Beta radiation• Gamma radiation• Neutron radiation

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Alpha radiation

• Range-~ Very short, about 1 to 2 inches in air

~ Deposits large amount of energy in a short distance of travel

~ This large energy deposit is what limits the penetrating ability to a very short distance

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Alpha radiation (cont.)

• Shielding-~ Most alpha particles are stopped by:

◦ only a few centimeters of air,◦ a sheet of paper,◦ the dead layer of skin on a human body.

• Biological Hazards-~ No external hazard.

~ Internally, the source is in close contact with body tissue and can deposit large amounts of energy to a small body of living tissue.

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Alpha radiation (cont.)

• Common sources-~ Uranium

~ Thorium

~ Plutonium

~ Radium

~ Radon

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Beta radiation

• Range-~ Short distance, depending on the energy of

the particle, about 1 inch to 20 feet~ In the case of tritium (H3), the range is only

one inch~ In the case of phosphorous-32 (P-32) or

strontium-90 (Sr-90), the range is 20 feet

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Beta radiation (cont.)

• Shielding-~ Beta particles are typically shielded by plastic or glass

◦ The sample containers generally shield the outside environment from a beta emitter

◦ Your safety glasses will shield your eyes (note - very important!)

Important note for licensed facilities using hand held friskers! – When frisking samples for radioactivity,

you may receive a false negative with closed containers!

• Biological Hazards-~ Internal hazard due to short range and lower penetrating power.~ Externally, a beta emitter may be hazardous to the skins and

eyes.

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Beta radiation (cont.)

• Common sources-~ Potassium 40 (K-40)

~ Strontium 90 (Sr-90)

~ Cesium 137 (Cs-137)

~ Cobalt 60 (Co-60)

~ Tritium (H3)

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Gamma radiation

• Range-~ Very high range, easily can go several hundred

feet or more.

~ Very high penetrating power since it has no mass and no charge.

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Gamma radiation (cont.)

• Shielding-~ Very dense material

◦ Concrete◦ Water◦ Lead

• Biological hazards-~ Can result in whole body exposure

~ Hazard may be internal or external depending on location of source.

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What about protection from radiation?

• Source reduction-~ Put the larger volume of samples away, remove and only work with

aliquot needed.~ Decontaminate the area around you.

• Practice the three principles of radiation protection:~ Time – Time spent away from radioactive emitters,~ Distance – Distance yourself from the emitters,~ Shielding – Shield yourself from high emitters.

• Practice ALARA!~ As Low As Reasonably Achievable.~ Always reduce your exposure as much as possible, simply reducing

to a licensed limit is never enough. This means that if the NRC states that you can safely handle 5 REM in a year, but you have the means to reduce your exposure even further , you must reduce it.

• Remember, these same safe practices help to protect against known and unknown chemical hazards as well.

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Permissible Exposure Limits

• Nuclear Regulatory Commission = 5 REM (50mSv) per year for a radiation worker,100 mrem (1 mSv) per year for a member of the general public.

• Test America = action level is 500 mrem (5 mSv) per year, 1/10th of the NRC limit (same as NRC “Pregnant Worker”).

• What is “REM”?~ The acronym for Roentgen Equivalent Man is a

standard unit that measures the effects of ionizing radiation on humans.

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Risk in Perspective (cont.)

• Estimated Average Whole Body Dose from Natural & Man-made Sources:

• Naturally Occurring-~ Cosmic Radiation = 39 mrem/yr.~ Internal, principally K-40 = 26 mrem/yr.~ External Terrestrial = 235 mrem/yr.

– Earth’s crust~35mrem, Radon gas~200mrem

• Man-made-~ Fallout = 1mrem/yr.~ Medical uses (x-rays, internal sources) = 90mrem/yr., avg.

chest x-ray~10mrem ea.~ Tobacco products = 1300 mrem/yr.~ Building materials = 7mrem/yr.~ Domestic water supply = 5mrem/yr.

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Risk in Perspective (cont.)

• Reduction of Life Span from Various Causes=~ Smoking (one pack/day) ~ 9 yrs.~ Living in city vs. country ~ 5 yrs.~ Being single vs. married ~ 5 yrs.~ Desk job vs. field job ~ 5 yrs.~ Being male vs. female ~ 3 yrs.~ Obesity ~ 2 yrs.~ Alcohol consumption ~ 1 yr.

• Radiation=~ Cosmic ~ 20 – 30 days~ Terrestrial ~ 50 – 100 days~ Medical ~ 30 days~ Luminous watch ~ <26 days~ World fallout ~ 1 day~ Occupational dosage of 1rem/yr. ~ 51 days

◦ Note – this is twice TestAmerica’s internal limit!

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Basic Analytical Instrumentation

• Gamma Spectrometry• Gas Flow Proportional Counting• Liquid Scintillation Counting• Alpha Spectrometry• Lucas Cell (Scintillation Detector)• ICP-MS

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Gamma Spectrometry

• Detector (High Purity Germanium)• aka HPGe• Semiconductor Detector (cryo temp)• High Resolution (Low FWHM)

• Electronics• Collect and Process Signal from

Detector• MCA is key component

• Software• Store and analyze the spectrum

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Gas Flow Proportional Counting

• Detector• Gas-filled (P-10; 90% Argon, 10% methane)

chamber with thin window (e.g. mylar film, 80μg/cm2)

• Electronics• Collect and Process Signal from Detector• Pulse shape discrimination key function

• Software• Store and analyze the

spectrum

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Liquid Scintillation Counting

• Detector• Photomultiplier tube (PMT) collects light

• Electronics• Collect and Process Signal from

Detector• Utilizes MCA for spectral output

• Software• Store and analyze the

spectrum

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Alpha Spectrometry

• Detector • Ion-implanted-Si Charged particle detector• Low Resolution (High FWHM) compared to γ

• Electronics• Collect and Process Signal from Detector• MCA is key component

• Software• Store and analyze the spectrum

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Lucas Cell Counting

• Used specifically for Ra-226 by radon emanation (Richland)

• Silver-activated zinc sulfate coating scintillates when struck by alpha particle

• Photomultiplier tube measures scintillation• Each event recorded on counter/scalar

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ICP-MS

• Inductively Coupled Plasma – Mass Spectrometry

• Direct Mass Measurement• Can convert results to activity • Useful for long-lived isotopes• Uranium• Tc-99 • Th-232

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What is NORM?

• Naturally Occurring Radioactive Material

• Terrestrial – primordial radionuclides present in rocks and minerals

• Cosmogenic - interaction of cosmic nucleons with atmosphere (varies with altitude)

• Dose~ 31 mR/yr in St. Louis~ 55 mR/yr in Denver

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NORM(Naturally Occurring Radioactive Materials)

• Terrestrial~ K-40~ Nuclides in Primordial Series

◦ Uranium-238 (Uranium Series)◦ Thorium-232 (Thorium Series)◦ Uranium-235 (Actinium Series)

• Cosmogenic (H-3, C-14, Be-7)

• Principal Nuclides of concern (typically)~ Ra-226, K-40, Th-232

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TENORM(Technology Enhanced NORM)

• Produced when NORM are exposed to the environment or concentrated; extraction/treatment/purification (EPA)~ Minerals Mining & Production/Processing

(e.g. phosphogypsum)

~ Coal Ash Generation

~ Oil & Gas Production

~ Sewage or Drinking Water Treatment

~ Consumer Items

Key Methods/Isotopes(SDWA-related)

• Gross Alpha/Beta (3/4 pCi/L) • Ra-226/Ra-228 (1 pCi/L)/(1 pCi/g)• Sr-90 (1 pCi/L)/(1 pCi/g)• H-3 (300 pCi/L)/(2 pCi/g)• Uranium (Total/Iso)• K-40 (Beta minus K-40)

“If it is good enough to drink, it is good enough to pour down the drain.” This idea is not appropriate for all situations, and is overused.

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Beta/Photon Emitters

“Most systems will never need to monitor for beta particle and photon radioactivity”*

*Radionuclides in Drinking Water: A Small Entity Compliance Guide, EPA (2002)

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Key Methods(Other)

• Alpha emitters• Iso-U, Iso-Th, Am-241, Iso-Pu, Np-237, Po-210

• 1 pCi/L / 1 pCi/g to lower than 0.1 pCi/L / 0.1 pCi/g

• Beta emitters• C-14, Tc-99, Pb-210, Ni-63, Pu-241, Cl-36

• Gamma emitters• Co-60, Cs-137, Fe-55, I-129 (I-125)

• 20 pCi/L / 0.2 pCi/g based upon Cs-137

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Trash/Treasure

• One man’s trash is another man’s treasure:~ Fly ash – concrete, cement, concrete block

~ Bottom ash – snow/ice control

~ Boiler slag – blasting grit, roof granules

~ Sludges – wallboard, roadbases

~ Phosphogypsum – used in agriculture as a source of calcium and sulfur, for pH adjustment, and for erosion control.

~ Phosphate slag – used in roadbase (crushed) and as aggregate for asphalt; Portland cement and concrete; railroad ballast and construction

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Regulations

• Regulations: ~ TENORM not directly regulated by Atomic

Energy Act (AEA)◦ except mill tailings (Thorium/Uranium)

◦ source material (high grade ores)

~ Clean Air Act (NESHAPS): regulates release of TENORM to air from phosphate industry and uranium mining

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Phosphate Industry Regs

• NESHAPS standard for airborne Po-210 also effectively controls Pb-210.

• Slag contains ~15x background gamma rays. Radon is mostly encapsulated by the slag. A NESHAPS standard does exist for radon emissions from phosphogypsum stacks.

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Uranium Mining Regs

• Open Pit mines:~ Not many active. Large area of overburden

topsoil and open pit area, exposing Radium (Radon). EPA study – low health risk. Already regulated by state and federal mining laws. No NESHAPS put into place.

• Underground mines:~ 1989 NESHAPS regulates Radon emissions from

underground mines (vents – potentially high emissions).

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Other Regulations

• Clean Water Act (CWA) – through NPDES, EPA has authority to regulate discharges into surface waters that don’t fall under AEA Permits issued will include criteria for TENORM for uranium, thorium, etc mines/mills.

• Safe Drinking Water Act (SDWA) – National Primary Drinking Water Regulations includes limits for radionuclides. Most recently revised in 2000.

• CERCLA (Superfund) – establishes preliminary remediation goals (PRGs) for soils contaminated with uranium, thorium, radium, et al.

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Questions/Contact Info

• Terry Romanko – Radiochemistry Technical Director• St. Louis Laboratory• terry.romanko@testamericainc.com• 314-298-8566

Questions?