Radiation: Sources, Effects and Uses

1. Radiation: Sources, Effects and Uses Mark Pierson Associate Professor Virginia Tech The Foundation for Nuclear Studies Longworth 1539November 4, 2011 10:00 AM

2. Fear of Radiation - Radiophobia • Why is there so much fear by the public about radiation? • Cannot see it, feel it, or sense it • Did not learn about it in school • Mysterious and unknown (like the bogey man) • Can cause serious health effects in LARGE amounts • Other ideas from the audience?

3. Types of Radiation • Alpha particle decay α • High charge (+2), high mass (4 amu) particle • Deposits all of its energy in a very short distance Daughter Nucleus 222Rn  Parent Nucleus 226Ra Alpha Particle (Helium Nucleus)

4. Types of Radiation • Beta particle decay β • An electron emitted from nucleus, negatively or positively charged (-1 or +1) Daughter Nucleus Nickel -60 Z= 28  Antineutrino Parent Nucleus Cobalt -60 Z= 27  Beta Particle (electron)

5. Types of Radiation • Gamma Ray emission  • A high energy photon  Daughter Nucleus Nickel-60 Parent Nucleus Cobalt-60 (Beta decay) Gamma Rays

6. X-rays Types of Radiation • X-Ray emission  • A low energy photon Bremsstrahlung X-Ray

7. Types of Radiation • Electromagnetic spectrum

8. Types of Radiation • Ionizing Radiation Electron ejected from orbit + Ion - Ion Ionizing radiation

9. Types of Radiation alpha • Penetrating Radiation alpha High charge, dense ionization, short path beta Less mass/charge than alpha, longer path gamma No charge or mass, much less interaction neutron No charge, interacts through nuclear events

10. Types of Radiation • Shielding radiation Lead Concrete Paper Plastic Alpha  Beta  Gamma and X-rays g Neutron n

11. Radiation Dose • Units of radiation dose equivalent • U.S. unit is the rem or millirem (1 mrem = 0.001 rem) • International unit is the Sievert (Sv), milliSievert (mSv), or microSievert (μSv) • 1 mSv = 0.001 Sv • 1 μSv = 0.001 mSv = 0.000001 Sv • Multiply Sieverts by 100 to obtain rem • Divide mSv by 10 to obtain rem • 1 mSv = 100 mrem = 0.1 rem

12. After Image (film) Subject is not radioactive but has been exposed to a radiation dose (single chest xray = 5-10 mrem). Radiation Dose • External Dose X-Ray Machine

13. Cosmic Rays Radiation Everywhere Solar Radiation Nuclear Medicine X-Rays •  Radon Consumer Products Each Other Radioactive Waste Nuclear Power Terrestrial Radiation Food & Drink

14. Average Dose in U.S. is 620 mrem/year

15. Radiation Perspective • 200 mrem/yr from Radon in your home • 4 mrem from round trip airline flight from NYC to LA • 200 to 400 mrem/yr for flight crews • 10 mrem typical chest x-ray • 1000 mrem = 1 rem from torso CT scan • 30 mrem from food and water consumed throughout the year • 100 mrem from a mammogram We are showered in radiation daily

16. Annual Radiation Limits due to Occupational Exposure

17. Measuring Radiation Effects • How much radiation is produced? • Activity: decays per unit time (Curies, Becquerel) • How much energy is absorbed by tissue? • Dose • How much biological damage does the radiation do per energy absorbed in the tissue? • Dose Equivalent

18. Pathways into the Body

19. Potassium Iodide (KI) • Do not buy potassium iodide pills • Do NOT take potassium iodide in the U.S. due to radioactivity released by the Japanese nuclear plants • KI is a drug and may have side effects • There is no benefit

20. Radiation Damage to Cells

21. Radiation Induced Water Decomposition H2O H2O+ H2 e- H+ Incoming Radiation WATER OH- Ho HO2 H2O2 OHo Production of free radicals within the cell can result in indirect effects

22. Damage to DNA • Radiation can have a direct effect on the DNA molecule in a cell by ionization or excitation of the molecule and subsequent dissociation of the molecule • Many other entities cause breaks in DNA • Temperature, chemicals, etc. • Human DNA suffer millions of DNA breaks daily • Most are repaired

23. Outcomes of Radiation Interaction with Cells • All radiation interactions do not result in cancer • Within a person’s body, 10 million cells are struck by ionizing radiation per minute from naturally-occurring radioactive isotopes (e.g., K-40, C-14) and background radiation • Cells have a high capability for repair through the action of the cell itself or replacement of badly injured cells by mitosis of healthy cells

24. Cell Repair After Chronic Dose Damage Radiation Dose Reparable Accumulated Irreparable Time

25. Genetic Defects in Humans • NO direct evidence of radiation-induced genetic effects in humans, even at high doses. • Analyses indicate rate of genetic disorders produced in humans would be extremely low, on the order of a few disorders per million live born per rem of parental exposure 

26. Time radiation dose received Latent period Period at risk Risk curve Risk 0 4 30 Time (years) Cancer Latency • Latency period is the time from exposure until the effect is exhibited • Radiation exposure does not produce cancer in every exposed person • Cancer latency can be 10 to 20 years later for high radiation doses Leukemia latency and time at risk periods

27. Linear No Threshold (LNT) Model Known damage due to dose of about 10,000 to 100,000 mrem • S = Supralinear – higher than expected damage at low dose levels • L = Linear – damage is proportional to the dose, always some damage • T = Threshold – below a certain dose level there is no biological damage • H = Hormesis – low level doses can actually be beneficial to your health

28. Radioactivity from Fukushima • Radioactivity limit for I-131 is 1 pCi/ml in water • A typical banana has 540 pCi, eating one-a-day could yield about 3 mrem/yr • Traces of I-131 detected in rain water and milk in U.S. from Fukushima have been well below limits • Impact to the U.S. population from the radioactivity released in Japan is essentially nonexistent • No known effects from radioactivity released during Three Mile Island accident to those within 50 mi

29. Food Safety • Who has suffered from food poisoning? • How much more would you pay for food if you could reduce significantly the probability of getting sick? • According to the Center for Disease Control, in 1999, food-borne disease was responsible for: • 76 million illnesses, 325,000 hospitalizations, 5000 deaths,$6-30 billion impact • UN Food Administration Organization • ~25% of worldwide food production is lost after harvesting due to insects, bacteria and spoilage

30. Food Irradiation • New commercial technology to eliminate disease-causing germs • Comparable to pasteurization… but cold • Food is exposed to carefully controlled amounts of ionizing radiation (gammas, high-energy electrons) • Radiation damages DNA of microbes and parasites • Reduces disease-causing germs • Kills bacteria that cause spoiling • Slows or stops sprouting in vegetables uw-food-irradiation.engr.wisc.edu

31. Results of Food Irradiation • When used in conjunction with proper food handling procedures: • food-borne diseases are reduced or eliminated • shelf-life is increased • the nutritional value of the food is preserved • the food does not become radioactive • dangerous substances do not appear in the foods

32. Approval Year Food Purpose Eggs Wheat Flour Control of mold Kill Salmonella 1963 2000 White Potatoes Inhibit sprouting 1964 Pork Kill Trichina parasite 1986 • Insect Control • Increase Shelf Life 1986 Fruit and Vegetables Herbs and Spices Sterilization 1986 1990(FDA) 1992(USDA) Poultry 1997(FDA) 1999(USDA) Meat School Lunch Program E-coli & Salmonella 2003 What Foods Can Be Irradiated? Bacterial pathogen reduction

33. Food Irradiation Facility

34. Radiation Level Gauge

35. Radiation Thickness Gauge

36. Cereal Boxes • Filled using radiation level gauge

37. Soda Cans • Radiation used in making and filling the cans

38. Blue Topaz • Color created by neutron irradiation in a reactor

39. Cosmetics • Irradiated to remove harmful bacterial impurities

40. Environmental Protection • Electron beam cleans flue gas from fossil fuel plants • Electron beam ionizes SO2 & NOx • SO2 & NOx react with injected Ammonia ==> Solid fertilizer

41. Comparision of Radiation Technology to… • Fortune 500 Companies

42. Comparision of Radiation Technology to… • Major industries in U.S.

43. Radiation Conclusions • Humans are made of radioactive material and we eat radioactive foods • We are exposed to radiation everywhere in our daily lives • Low levels of radiation are not harmful • Large amounts of radiation can cause cancer many years later, but no genetic effects • We use radiation technology for everyday uses that improve our lives • There is no reason to be afraid of radiation • You now know more than the rest of the general public --- so be empowered to use your knowledge

44. Questions?

45. What happens after Fukushima Daiichi natural disaster?

46. U.S. public opinion of nuclear energy fell after Fukushima but is now reversing Luntz Global survey on behalf of Nuclear Energy Institute

47. Survey results six months after Fukushima by Bisconti Research with GfK Roper are promising • 62% favored used of nuclear energy for electricity generation. Those strongly favoring nuclear energy outnumbered those strongly opposed by two-to-one. • 67% rate U.S. nuclear power plant safety as high • 59% agree that we should definitely build more nuclear power plants in the U.S. in the future • 85% agree that we should renew the licenses of those nuclear power plants that continue to meet federal safety standards • 67% agree that it would be acceptable to build another nuclear reactor at the closest nuclear power plant to them