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Penn State University Radionuclide Safety Training

Penn State University Radionuclide Safety Training. Environmental Health and Safety Radiation Protection 865-6391 Created by Russel O. Dunkelberger II, Revised Sept. 2004. 1. Introduction. Introduction.

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Penn State University Radionuclide Safety Training

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  1. Penn State UniversityRadionuclide Safety Training Environmental Health and Safety Radiation Protection 865-6391 Created by Russel O. Dunkelberger II, Revised Sept. 2004

  2. 1. Introduction

  3. Introduction • University rules and Nuclear Regulatory Commission (NRC) regulations require that anyone working with or around ionizing radiation must be instructed about the possible hazards of radiation exposure and the procedures to be used for the safe handling of radioactive materials.

  4. The Senior Vice-President for Research and Dean of the Graduate School: • Is the University official responsible to the NRC for assuring that radioactive material is used according to the conditions of the NRC regulations and licenses. • Appoints the University Isotopes Committee (UIC) to establish and oversee the policies for the use of radioactive material

  5. Members of the UIC are: • Chair: Craig Baumrucker, PhD; Animal Nutrition and Physiology • Jack Brenizer, Ph.D.; Nuclear Engineering • Eric Boeldt; Radiation Safety Officer • David Gilmour, PhD; Molecular and Cell Biology • Andrea Mastro, PhD; Microbiology and Cellular Biology • Robert Paulson, PhD; Veterinary Science • Catherine Ross, PhD; Nutrition • John E. Smith, PhD; Human Nutrition • Candice A. Yekel; Director, Office of Regulatory Affairs

  6. EHS - Radiation Protection Staff • Eric J. Boeldt, Radiation Safety Officer • Mark E. Linsley, Associate Health Physicist • Health Physics Specialists: • Gregory Herman • David A. Bertocchi • James P. Wiggins • Suzanne H. Morlang,Health Physics Assistant

  7. Environmental Health and Safety (EHS) • Provides radiation safety services including: • radiation monitoring • radioactive waste disposal • assistance with the use of radioactive material • Monitors the use of radioactive material for the UIC • Radiation protection staff are located at 228 Academic Projects Building • EHS offices are at 6 Eisenhower Parking Deck • Can be reached AT ANY TIME at 5-6391

  8. 2. Regulations

  9. NRC Regulations • Available from EHS • 10 CFR 19 • Requirements for instruction of personnel • Posting of Notices and inspections • 10 CFR 20 • Standards for radiation protection

  10. Form NRC-3 “Notice To Employees” • Posted in or near all radioactive materials use labs • Lists responsibilities of NRC licensees and persons working with radioactive material • Provides the address and phone number to contact the NRC

  11. Things you should know… • Licensed radioactive material may only be used by, or under the direct supervision of, individuals approved by the UIC (almost always permanent professors) or under the specific reactor license. • Licensed radioactive material may not be used in tracer studies involving direct release of licensed material to the environment. • Radioactive material may not be administered to humans or be added to food, beverage, cosmetic, drug or any other product designed for ingestion or inhalation by, or application to, humans.

  12. More things you should know... • Purchases and/or transfers of radioactive material are to be made through EHS. This includes transfers between authorized users at the University as well as between the University and other institutions. • If you loan any radioactive material to another lab, call EHS so we can process the transfer. • The UIC will not hesitate to impose sanctions on radionuclide users who do not comply with the conditions of their authorizations to use radioactive material.

  13. Even more things to know... • Individuals are also subject to civil penalties, if they willfully violate NRC regulations or license conditions. • Violations usually result in corrective actions that affect all persons working with radioactive material, not just the individuals responsible for the infractions. • If you have questions about the regulations, license conditions or procedures, contact EHS or a member of the University Isotopes Committee for advice.

  14. Other Regulatory Information • The University also has to operate under regulations and licenses issued by the Pennsylvania Department of Environmental Resources, Bureau of Radiation Protection. In general, the state regulations are identical to those of the NRC. • “The Rules and Procedures for the Use of Radioactive Material at the Pennsylvania State University” contains rules for working with radioactive material. A copy of these rules is provided to laboratory supervisors and is also available for download from www.ehs.psu.edu.

  15. 10 CFR 21:Notification of Defects • NRC licensees are required to identify and evaluate any defects that may potentially be a substantial radiological safety hazard, and any situation that leads to failure to comply with regulations. Such occurrences may need to be reported to the Nuclear Regulatory Commission. • If you suspect that any facility, activity or component fails to comply with federal regulations or creates a substantial radiological safety hazard, contact EHS immediately!

  16. 3. Properties of Radiation

  17. A = mass number = Z + N = total number of protons + neutrons N = number of neutrons Z = atomic number = number of protons X = element Nomenclature A X Z

  18. A = 14 protons and neutrons Z = 6 protons N = 8 neutrons C = Carbon Example 14 C 6

  19. Radioactive Material, Radiation and Contamination

  20. Radioactive Material • Radioactive material is a solid, liquid or gas compound or mixture in which some of the atoms present are radioactive atoms

  21. Radioactivity • Radioactivity is the natural property of certain nuclides to spontaneously emit energy, in the form of ionizing radiation, in an attempt to become more stable.

  22. Radiation • Radiation is the term given to the energy transmitted by means of particles or waves • It can be ionizing or non-ionizing

  23. Non-Ionizing Radiation • Examples: • Microwaves • Sunlight • Infrared Waves • Radio Waves • Lasers

  24. Ionizing Radiation • Ionizing radiation occurs from the addition or removal of electrons from neutral atoms. Four main types of ionizing radiation are alpha, beta, gamma and neutrons.

  25. Alpha Radiation () • Helium nucleus • 2 protons and 2 neutrons • Large, Slow, +2e charge • High linear energy transfer (LET) • Low penetrability • Decay: • Po  Pb + He 210 206 4 2 84 82

  26. Beta Radiation () • Electron emitted from nucleus • Small, Fast, -1e charge • Medium LET • Medium penetrability • Decay: • Neutron converted into a proton and an electron • P S + - +1.7 MeV 32 32 15 16

  27. Gamma () and X- Radiation (X) • Gamma rays and x-rays are photons • No mass, no charge, travel at speed of light • Low LET • High penetrability • Commonly accompany other radiation • Penetrability can vary; therefore, shielding and detection requirements vary

  28. Neutrons (n) • Neutral particle • Classified by energy • Fast neutrons - energy greater than 0.1 MeV • Thermal neutrons - same kinetic energy as gas molecules in the same environment • A concern at the nuclear reactor and with soil moisture probes • Emission of neutrons accompanies the splitting of Uranium and Plutonium nuclei

  29. Linear Energy Transfer (LET) • LET is used to describe the amount of energy imparted locally by ionizing radiation in a target. • The higher the value of a particle’s or wave’s LET, the greater the amount of damage that particle could potentially cause to the target.

  30. Penetrability • The ability of radiation to penetrate matter. • Alpha particles have a low penetrability and can be shielded by a piece of paper. • Beta particles have a higher penetrability and are usually shielded with Plexiglas. • Gamma rays have the highest penetrability of the three, and are shielded with thick concrete or lead.

  31. LET and Penetrability • On the following diagram, each dot represents a unit of energy deposited. As you will see from the diagram, alpha particles impart a large amount of energy in a short distance. Beta particles impart less energy than alphas, but are more penetrating. Gamma rays impart little energy and are the most penetrating. Remember, gamma and x-rays vary widely in energy. The diagram shows a high energy gamma ray.

  32. LET and Penetrability

  33. Radiation Units • Exposure • Charge produced in air from ionization by gamma and x-rays; Unit: Roentgens, R • Radiation Absorbed Dose • Energy deposited by any form of ionizing radiationin a unit mass of material; Unit: rad • Dose Equivalent • Scale for equating relative hazards of various types of ionization in terms of equivalent risk; Unit: rem (1 rem = 1,000 mrem)

  34. Radiation Units • Activity • Measure of the amount of radioactivity present • Units: Curie, Ci; or Becquerel, Bq • Becquerel = one decay per second (dps) • Curie = dps occurring in the quantity of radon gas in equilibrium with one gram of radium 1 Ci = 2.22 x 1012 dpm = 3.7 x 1010 Bq 1 Ci = 2,220,000 dpm = 37,000 Bq

  35. Half-Life and Decay • Each radioactive nuclide has its own unique characteristic pattern of decay, based on: • Types (alpha, beta, etc.) and energies of the emission involved • Rate of decay, or half-life. • A radionuclide’s half-life is the amount of time it takes for one-half of the radioactive atoms present to disintegrate or decay.

  36. Decay Calculation A = A0e-t • Where: A = Activity at time, t A0 = Initial activity  = ln 2 / half-life t = Elapsed time

  37. Example • If you have 1 mCi of P-32 initially, how much P-32 would remain after 8 weeks? Assume P-32 has a half-life of 14 days. • A = (1 mCi) e-[(Ln 2 / 2 weeks) (8 weeks)] • Note that the half-life of 14 days was converted to 2 weeks, so that the units match with the elapsed time period. • A = (1 mCi) e-[(0.693 / 2 weeks) (8 weeks)] • A = (1 mCi) e-[(.347 / weeks) (8 weeks)] • A = (1 mCi) e-(2.77) • A = (1 mCi) (0.0625) • A = 0.0625 mCi

  38. Is There an Easier Way? • There sure is! Draw a chart, as shown below, to get a quick estimate of activity remaining at time, t. For 1mCi of P-32, Elapsed time, t # half-lives Activity 0 weeks 0 1 mCi 2 weeks 1 0.5 mCi 4 weeks 2 0.25 mCi 6 weeks 3 0.125 mCi 8 weeks 4 0.0625 mCi

  39. 4. Radiation Biology

  40. Sources of Radiation • Average person receives 360 mrem per year • Natural Sources 295 mrem (82%) • Terrestrial 228 mrem • Human Body 40 mrem • Cosmic 27 mrem • Man-made 65 mrem (18%) • Medical 15 mrem • (chest x-ray ~10 mrem) • Products 10 mrem • (tobacco, cosmetics, etc.) • Other 2 mrem • (occupational, fallout, nuclear power, etc.)

  41. Biological Effects to Typical Occupational Exposures From NRC Regulatory Guide 8.29: (available at http://www.nrc.gov/NRC/RG/08/08-029.pdf) • Assessment of cancer risks associated with radiation exposure is projected from doses greater than 10 rem (10,000 mrem) • There is no scientific evidence that conclusively proves that lower doses of radiation cause cancer • However, for regulatory purposes, the NRC assumes that even small exposures to radiation carry some risk of causing cancer, and that this risk is linear below 50 rem (50,000 mrem)

  42. Biological Effects to Typical Occupational Exposures From NRC Regulatory Guide 8.29: • The risk of developing a fatal cancer per 1 rem (1,000 mrem) of exposure received is assumed to be about 1 in 2,500 (0.04%) • Approximately 1 in 5 adults (20%) normally die from cancer from all possible causes (smoking, food, drugs, pollutants, genetic traits, etc.) • Therefore, working with radiation may increase your risk of dying of cancer from 20% (no occupational radiation exposure) to 20.04% (1 rem total lifetime occupational radiation exposure)

  43. Estimated Loss of Life Expectancy from Health Risks* Health Risk Estimate of Life Expectancy Lost Smoking 1 pack cigarettes per day 6 years Being 15% overweight 2 years Alcohol consumption 1 year Being in any accident 1 year Natural hazards 7 days Medical radiation 6 days Occupational radiation exposure 300 mrem/year from age 18 to 65 15 days 1000 mrem/year from age 18 to 65 51 days *Adapted from B.L. Cohen and I.S. Lee, “Catalog of Risks Extended and Updated,” Health Physics, Vol. 61, September 1991.

  44. Biological Effects to Very High Levels of Radiation Exposure For a single exposure to extremely high levels of radiation (>50 rem), the following sequence of events may occur: • Latent period - time lag between the radiation event and the first detectable effect • Period of demonstrable effects on cells and tissues - discrete effects of radiation exposure may be observed • Recovery period - apparent in short-term (days to weeks) effects. May not occur for some residual damage, giving rise to long-term effects

  45. Acute Biological Effects to Very High Levels of Exposure • Common Symptoms 50 rem (50,000 mrem) • Nausea and vomiting, malaise and fatigue, increased temperature, blood changes • Hemopoietic Syndrome 200 rem (200,000 mrem) Ablation of bone marrow, death within months, if untreated • Gastrointestinal Syndrome 1000 rem (1,000,000 mrem) Desquamation of intestinal epithelium, death within weeks, if untreated • CNS Syndrome 2000 rem (2,000,000 mrem) Unconsciousness within minutes, death within days, if untreated • By comparison, the highest exposure at PSU last year was approximately 0.1 rem above natural background

  46. 5. Radiation Safety

  47. Radiation Safety • ALARA • Program developed in order to keep doses As Low As is Reasonably Achievable • Obtaining higher doses in order to get an experiment done quicker is NOT “reasonable”! • Three main ways to keep your doses ALARA: time, distance and shielding • Ask EHS for assistance in developing procedures that help keep your doses ALARA.

  48. Time, Distance and Shielding • Minimize your exposure time • Dry runs (without radioactive material) • Identify portions of the experiment that can be altered in order to decrease exposure times. • Make sure you have all necessary equipment • Maximize distance - Inverse square law • Doubling distance from source, decreases dose by factor of four • Tripling it decreases dose nine-fold • Use appropriate shielding

  49. Shielding • High-energy beta emitters (P-32) • Plexiglas (acrylic) shielding • Do not use only thin lead to shield beta emitters • production of bremsstrahlung x-rays • low-energy x-rays produced by beta interaction with a high-Z nucleus • Can shield with Plexiglas first, then with lead on the outside • Gamma emitters (I-125, Cr-51) • Lead or leaded acrylic • Neutrons • hydrogenous material: water, concrete

  50. Contamination Surveys • Required after EVERY use of unsealed radioactive materials - If you don’t have time to survey, you don’t have time to do your experiment! • Survey yourself, your benchtop, the floor, the non-radioactive trash and any other area that could potentially become contaminated • Use the appropriate instrument for the radionuclide you are using • Use the data on the next slide as a guide

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