Radiological/Nuclear Awareness

1. Radiological/Nuclear Awareness

2. The Atom • Three components make up atoms: • Protons (positive electrical charge) • Neutrons (neutral electrical charge) • Electrons (negative electrical charge) • The number of protons determines which element it is • One proton = hydrogen • 92 protons = uranium

3. Electrons • Normally, atoms have equal numbers of electrons and protons • May be altered if combined with other elements to make molecules (electron sharing) • Electricity is electrons moving from one atom to another • Atoms may be ionized

4. Stable/Unstable Atoms • The ratio of neutrons to protons is a good indicator of stability • Stable atoms generally have slightly more than one neutron for each proton • Unstable atoms (those having more neutrons) will attempt to give off the excess neutrons (radioactive particles or waves)

5. Ionization • The process of removing electrons from atoms • This process is not making the atom radioactive! • Ionizing radiation is excess energy that is capable of removing electrons from atoms

6. Ionizing Radiation • Ionizing radiation is excess energy (from radioactive, unstable atoms) what is capable of removing electrons from atoms • Alpha • Beta • Gamma • X-ray • Neutron

7. Non-ionizing Radiation • This type of radiation does not have enough energy to remove electrons from atoms • Includes such common things as: • Radio waves • Visible light • UV waves

8. Non-ionizing Radiation • The higher the frequency of electromagnetic waves, the more energy the waves have and the shorter the wave length • X-rays and gamma radiation are electromagnetic waves, but have more energy

9. Radioactivity • Radioactivity is the process of unstable (radioactive) atoms trying to be come stable by emitting ionizing radiation (alpha, beta, gamma, neutron) • Even when contained, it still emits radiation and may be a hazard • Radioactive material is not a contaminant until it is located in an unwanted place

10. Contamination • Radioactive contamination is radioactive material in an unwanted place • May be solid, liquid, or gas • May be easily spread from one place to another and may even be spread through the air by being suspended in the air

11. Radiological vs. Nuclear • Radiological refers to radiation or material that emits radiation • Terrorists may use these materials to construct dirty bombs and cause radioactive contamination • Nuclear refers to processes which involve the splitting a nucleus (fission) or combining nuclei (fusion) • Nuclear weapons, nuclear reactors, etc.

12. Measuring Radiation • Radiation dose is the radiation energy absorbed by the body and takes into account the biological effects • Rem is a measure of radiation dose • Millirem (mrem) is more practical, it is 1/1000th of a rem • Example: standing in a radiation field measured at 100 millirem/hour • At 1 hour, you’d receive 100 mrem dose • 1t ½ hour, you’d received 50 mrem dose

13. Types of Ionizing Radiation • Alpha radiation • Physically, large mass consisting of two protons, two neutrons, no electrons • Ionization occurs because of the large positive charge – it strips electrons from nearby atoms as it passes through materials • Range is usually 1-2 inches in open air • Shielding is 1-2 inches of air, a sheet of paper, cloth, the dead layer of skin (epidermis)

14. Types of Ionizing Radiation • Alpha radiation continued: • Biologically, alpha radiation is not considered an external radiation hazard. It is a hazard internally and may enter from being inhaled, ingested, or contamination of open wounds • Sources include: • Uranium, plutonium, americium, thorium, polonium

15. Types of Ionizing Radiation • Beta radiation • Small mass that is negatively charged and ejected from the nucleus at high speed • Ionization occurs due to the beta particle pushing or repelling electrons from nearby atoms • Beta radiation is can travel about 10 feet • Shielding is by ¼” of plastic, aluminum, thick clothing, safety glasses

16. Types of Ionizing Radiation • Beta radiation • Externally, beta radiation is hazardous to the skin and eyes • Internally, it is hazardous if inhaled, injested or contaminates open wounds • Beta particles are emitted from used nuclear fuel, nuclear weapons fallout, industrial sources (cesium, tritium), radioactive nickel in chemical agent detectors

17. Types of Ionizing Radiation • Gamma radiation/X-rays • Electromagnetic waves with more energy than light or radio waves • No mass or electrical charge • For our purposes, gamma and x-ray radiation are similar, gamma is more energetic • Gamma radiation strips electrons from everything in it’s path until it runs out of energy

18. Types of Ionizing Radiation • Gamma radiation/X-rays • Because they have no mass and no charge, they can travel hundreds of feet in the air • Because of their range, they must be shielded by very dense material (concrete, lead, water, dirt, steel) • These are considered whole body radiation hazards because they cause harm internally and externally

19. Types of Ionizing Radiation • Gamma radiation/X-rays • Uranium, plutonium, radioactive cobalt and cesium, industrial radioactive sources, medical radioactive sources • Most beta emitters will also emit gamma radiation

20. Types of Ionizing Radiation • Neutron radiation • Neutrons are ejected from the nucleus of an atom • It has mass but no charge • Ionization occurs as it crashes into the nucleus of another atom and causes it to eject part of its electrons • Can travel for hundreds of feet in air

21. Types of Ionizing Radiation • Neutron radiation • Best shielded by materials with high hydrogen content like water or plastic. Concrete, and dirt are also good • Neutron radiation is a whole body hazard, affecting both external and internal structures • Produced in nuclear reactions inside reactors, nuclear weapons detonation and some radioactive materials

22. Radioactive Particles • Alpha, beta and neutron radiation are particles, meaning they have mass • They are smaller than an atom, so they are not visible and are not affected by the wind • However, they can contaminate dust particles and become wind borne

23. Radioactive Contamination • Radioactive contamination is radioactive material in an unwanted place • Radioactive contamination is caused by radioactive material • It may be solid, liquid, or gas or may be in an “interstate” like dust (solid suspended in air) or an aerosol (liquid droplets suspended in air) • This is not the same as radioactive particles

24. Exposure vs. Contamination • Exposure to radiation is like getting a sunburn or an x-ray • Contamination is like getting dirty by the radioactive material, not the particles or waves given off by the materials

25. Protection from Radiation • ALARA • As Low As Reasonably Achievable • Accomplished by time, distance and shielding

26. Time • Minimize the exposure time as much as possible • This shortens the exposure, minimizing damage

27. Distance • Stay as far away from radioactive materials as possible • Doubling your distance from the material lessens your exposure by a factor of 4!

28. Shielding • Place anything in between you and the radioactive material • Thicker and denser is generally better, though not necessarily convenient or readily available

29. Recognition • The trefoil is international symbol for radioactive materials • Used on signs, labels and placards • The color of the trefoil is irrelevant • The background color that the trefoil is on does matter!

30. Radioactive Labels • Label – individual packages of radioactive materials (not entire shipments!) • White/red l – minimal levels of radiation outside the package • Yellow/red ll – medium levels of radiation outside the package • Yellow/ red lll – highest allowed levels of radiation outside the package

31. Radioactive Placard • Large quantities of low level radioactive materials are placarded • Any quantity of high level radioactive materials are placarded

32. Health and Medical Effects • Natural background radiation • Cosmic radiation provides about 26 mrem/year • Terrestrial radiation (soil and other ground related sources) provides about 28 mrem/year • Internal sources provide about 40 mrem/year • Radon provides about 200 mrem/year

33. Health and Medical Effects • Man-made radiation sources • Tobacco products provide a total average dose of about 1300 mrem/year for smokers • Medical radiation provides about 54 mrem/year (5-10 mrem per chest x-ray) • Building materials provide about 7 mrem/year • Domestic water provides about 5 mrem/year

34. Health and Medical Effects • Minor sources of radiation • Atmospheric nuclear weapon testing (about 1 mrem/year) • Consumer products (about 10 mrem/year) • TV’s, radium dial watches, smoke detectors • Industrial sources (about 1 mrem/year) • Airport X-ray machines, VTD’s, tungsten welding rods

35. Health and Medical Effects • Medical effects • Radiation impacts • Atoms • Molecules • Cells • Tissues • Body

36. Health and Medical Effects • Some body cells are much more sensitive • Blood • Cells that produce sperm • Intestinal tract cells • Hair follicles

37. Health and Medical Effects • Cells may react to radiation exposure by: • Having no damage • Repairing the damage and operating normally • Not repairing or repairing badly and not operating normally • Dying

38. Health and Medical Effects • Radioactive materials may enter the body in any of the ways any other hazardous material may enter • Inhalation • Ingestion • Absorption • Injection

39. Health and Medical Effects • Radiation exposure can be • Acute • Large dose over a short time • Chronic • Small repeated doses over a long time

40. Health and Medical Effects • Acute radiation exposure • Burns, nausea, vomiting, cancer, death • Can be terotogenic, mutagenic and carcinogenic

41. Health and Medical Effects • Acute radiation effects does (in mrem) • < 50,000 mrem – no symptoms • 50,000 to 100,000 mrem – temporary lowering of WBC • 100,000 to 200,000 mrem – nausea, vomiting, diarrhea, malaise, no permenant disability • 200,000 to 450,000 mrem – vomiting/diarrhea appear earlier and are more severe, temporary loss of hair, sterility

42. Health and Medical Effects • 450,000 mrem – LD50 within 60 days • 600,000 mrem – death for most people

43. Health and Medical Effects • The risk of fatal cancer from ionizing radiation exposure increase .8% per 10,000 mrem

44. Emergency Scene Radiation • EPA guidelines allow the following radiation exposure: • 5000 mrem (all activities) • 10,000 mrem (protecting major property and no alternative exists) • 25,000 mrem (lifesaving or protection of populations and no alternatives exist) • 25,000+ mrem (lifesaving or protection of populations and no alternatives exist and only on a volunteer basis)