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Radiation Safety and Operations

Radiation Safety and Operations. The University of Montana-Missoula. How most of us feel about radiation until we understand the principles of safe use:. Today’s Mixed Message.

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Radiation Safety and Operations

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  1. Radiation Safety and Operations The University of Montana-Missoula

  2. How most of us feel about radiation until we understand the principles of safe use:

  3. Today’s Mixed Message The amount and type of radionuclides used at the University of Montana do not pose undue risk HOWEVER The Nuclear Regulatory Commission does NOT have a sense of humor

  4. NRC Enforcement Policy …”Prompt and vigorous enforcement action will be taken when dealing with licensees and their employees who do not achieve the necessary meticulous attention to detail and the high standard of compliance which the NRC expects…”

  5. What are we not talking about? At least not much Non-Ionizing Radiation

  6. Non-Ionizing Radiation from High to Low Frequency

  7. Radiation and Radioactive Material are 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. Smoke Detector

  8. Unstable 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), decays per minute (dpm), and Becquerels (decays per second). • When an unstable atom decays, it transforms into another atom and releases it’s excess energy in the form of radiation. Radiation can be • Electromagnetic radiation (like X or gamma rays), and • Particles (like alpha, beta, or neutron radiation) • Sometimes the new atom is also unstable, creating a “decay chain”

  9. 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 Example: • Some natural isotopes (like uranium and thorium) have half-lives that are billions of years,

  10. Most medical isotopes (like Technicium-99m) last only a few days Half Life Calculation

  11. Some Isotopes & Their Half Lives

  12. The Amount of Radioactivity is NOT Necessarily 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 sameactivity as1800 tons of natural Uranium

  13. Four Primary Types of Ionizing Radiation:Alpha Particles Alpha Particles: 2 neutrons and 2 protons They travel short distances, have large mass Only a hazard when inhaled

  14. Four Primary Types of Ionizing Radiation:Beta Particles Beta Particles: Electrons or positrons having small mass and variable energy. Electrons form when a neutron transforms into a proton and an electron or:

  15. Four Primary Types of Ionizing Radiation:Gamma Rays Gamma Rays (or photons): Result when the nucleus releases Energy, usually after an alpha, beta or positron transition

  16. Four Primary Types of Ionizing Radiation:X-Rays X-Rays: Occur whenever an inner shell orbital electron is removed and rearrangement of the atomic electrons results with the release of the elements characteristic X-Ray energy

  17. Four Primary Types of Ionizing Radiation:Neutrons Neutrons: Have the same mass as protons but are uncharged They behave like bowling balls

  18. Four Primary Types of Ionizing Radiation • Alpha particles • Beta particles • Gamma rays (or photons) • X-Rays (or photons) • Neutrons

  19. Shielding for ,  and  BASIC CONCEPT is to: Place materials between the source and person to absorb some or all of the radiation

  20. Direct Ionization Caused By: • Protons • Alpha Particles • Beta Particles • Positron Particles

  21. Indirect Ionization Caused By: • Neutrons • Gamma Rays • X-Rays

  22. DNA and Radiation

  23. Ionizing Radiation at the Cellular Level • Causes breaks in one or both DNA strands or; • Causes Free Radical formation

  24. Cellular Effects

  25. Cellular Effects Cell death Cell repair Cell change Is this change good or bad?

  26. Our Bodies 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

  27. Dividing Cells are the Most Radiosensitive • 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)

  28. At HIGH Doses, We KNOW Radiation Causes Harm • High Dose effects seen in: • Radium dial painters • Early radiologists • Atomic bomb survivors • Populations near Chernobyl • Medical treatments • Criticality Accidents • In addition to radiation sickness, increased cancer rates were also evident from high level exposures.

  29. Effects of ACUTE Exposures *

  30. Old Terms • Roentgen-Based on the quantity of electrical charges produced in air by X or Gamma photons 1R=2 billion pr • RAD-Radiation Absorbed Dose is the work energy resulting from the absorption of one ROENTGEN or 6.24 E5 Mev

  31. More Old Terms • REM-Roentgen Equivalent Mammal is equal to the absorbed does in RADS multiplied by a quality factor • Quality Factors • Beta = 1 • Gamma & X ray photons = 1 • Alpha = 10 • Neutrons = 20

  32. New Terms sort of International Units have replaced the RAD and REM GRAY (Gy) = 100 RAD SIEVERT (Sv) = 100 REM Same Quality Factors apply to the Sv

  33. Units of Radioactivity • Curie (Ci) = 2.22 E12 dpm or 3.7E10 dps • Becquerel (Bq) = 1 dps • Maximum Dose/year = 5 REM or 50 mSv • Maximum Dose/year for Declared Pregnant Woman & Minors= 0.5 REM or 5 mSv

  34. Adult ($18 yrs) Minor (< 18 yrs) Whole body* 5000 mrem/yr 500 mrem/yr Lens of eye 15000 mrem/yr 1500 mrem/yr Extremities 50000 mrem/yr 5000 mrem/yr Skin 50000 mrem/yr 5000 mrem/yr Organ 50000 mrem/yr 5000 mrem/yr Annual Dose Limits External/Internal Exposure Limits for Occupationally Exposed Individuals • *Effective dose equivalent

  35. Typical Doses

  36. Radiation is a type of energy; Contamination 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

  37. RAD use at UM • Prior to first use of radionuclides, the Authorized User must provide written and interactive training. • Read the Radiation Safety Manual • Specific, clear and detailed instruction on safe handling • Documentation

  38. Ordering Radionuclides Rad orders may be emailed or faxed to EHOS and must include an index code EHOS will place order and enter charges in Banner for you—This allows us to check inventory totals prior to ordering

  39. What if I Don’t Pay for my Nukes Free shipments must be approved Inter-Laboratory Transfers must Be approved

  40. Incoming Shipments • LOOK FOR DAMAGE OR LEAKAGE • Use the appropriate survey meter to confirm the TYPE and AMOUNT of detectable radiation is proper • Wipe test outer package and run wipes in LSC • Check each inner increment of packaging • Record the Results on your inventory sheet in the Rad Manual • Notify the RSO if any contamination is found

  41. Security • All Radioactive Materials must be secured or under direct supervision at all times • There MUST be someone in the room at all times OR the door must be locked.

  42. Contamination Surveys Record the Results Wipe tests must be done monthly if you have inventory on hand

  43. Spill Response • On Skin—flush completely • On Clothing—remove • If Injury—administer first aid • Radioactive Gas Release—vacate area, shut off fans, post warning • Monitor all persons and define the area of contamination

  44. ALARA As Low As Reasonably Achievable—means making every reasonable effort to maintain exposures to radiation as far below the dose limits as is practicable consistent with the purpose for which the licensed activity is undertaken, taking into account the state of technology, the economics of improvements in relation to the state of technology, the economics of improvements in relation to benefits to the public health and safety, and other societal and socioeconomic considerations, and in relation to utilization of nuclear energy and licensed materials in the public interest.

  45. Radiation Protection • Decrease Time • Increase Distance • Increase Shielding

  46. Reduce Waste Volume • Exercise care in handling—avoid spills • Use counter covers with overlays or cutouts • Keep primary rinse volumes to the minimum necessary

  47. Waste Handling

  48. Waste Handling

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