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Lim Jus494 Nucleartechnology


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  • 1. Nuclear Technology & Us JUS 394 Arizona State University Science, Technology & InEquality Professor: Merlyna Lim
  • 2. What IS Nuclear Technology Images of our world Weapons Reactors Nuclear waste Hiroshima Anti Nuclear Protests Media bring nuclear technology to our attention How to sort out the issues from the noise?
  • 3. Nuclear POWER
  • 4. Scientific Views for easy introduction:http:// ENERGY -- the driving force of change ENERGY -- heart of nuclear technology; radioactivity, nuclear fission, and nuclear fusion (reactions) are also driven by energy
  • 5. Energy plays an important part And it’s used in all this work; Energy, yest energy with power so great, A kind that cannot shirk. If the farmer had not this energy, He would be at a loss, But it’s sad to think, this energy Belongs to a little brown horse. A school verse by Richard Feynman a Nobel laureate for physics
  • 6. Nuclear ENERGY Energy forms -- transfer and conversion (recalling your high-school physics class!!) Part of nuclear technology -- for the conversion of nuclear energy into heat and electric energy; its development is related to the development of other technologies The Sun is a nuclear fusion reactor -- nuclear technology imitates the energy producing process of the Sun
  • 7. Nuclear Fission A process by which a heavy nuclide splits into two of more pieces -- became the top secret in Germany, England, the former USSR and the United States Transuranium: Fermi (1901-1954) in Rome, F. Joliot (1990-1958) and I. Curie in Paris, and Otto Hahn....
  • 8. Nuclear Fission Uranium isotopes -- 235U How much energy is released per fission reaction? How can the amount be estimated or calculated? What are the applications of fission energy in war and peace? 235U to give two nuclides --> 117Sn50, and 118Sn50, their masses being 116.902956 and 117.901609 amu respectively. The mass of 235U92 is 235.043924 amu. The difference in mass: 235.043924 - (116.902956 + 117.901609) = 0.2394 amu (931.5 MeV/1 amu) = 223 MeV. E=mc 2
  • 9. Common Perceptions watch?v=MRC5KDqpZ_I Are these images represent “the truth” behind nuclear technology? We should understand our own biases
  • 10. Nuclear weapons: Can any rational person make a case for their continued existence? Nuclear reactors: if they are very dangerous, can we afford to use them?
  • 11. Nuclear Technology & MEDIA Representation
  • 12. Radiation As constructed in the Media
  • 13. Media Stories Do I have to worry about radiation on airplanes? Is flying like working in a nuclear power plant? Does that mean nuclear plants are safe or flying is hazardous?
  • 14. Other Nuclear News
  • 15. Radon
  • 16. Radon Media Stories What is it Should I get my house tested? Is it related to nuclear power? Why didn’t someone tell me about it earlier?
  • 18. Radiation Fictions • Fear: – “It’s gonna blow!!!” • Controversy: – “We’re all gonna die!” • Misunderstanding: – “It’s not natural!” • Mistrust – “They’re all liars. We know mutant bugs will take over the earth and enslave us.”
  • 19. Nuclear Technology Too little we know on ‘what it is’ Dominant perception (mainstream political stories, media representation) reflect only partial truth Preconceived notions can hinder clear thinking and fruitful discussions Don’t we need to understand the basis of the technology to be able to come to ‘better’ decision? Doesn’t public deserve more information? Doesn’t public (us) need to be better informed?
  • 20. Radiation Facts It’s been around forever First was noticed ~ 1895 A lot was learned since then: – doctors & radiation could cure cancer – quacks & radiation could kill people – the Military & radiation could kill a LOT of people
  • 21. Environmental Radiation • Radiation & radionuclides older than the Earth • Natural part of our environment • Radiation field varies by geology, elevation, season, living conditions
  • 22. “Artificial” Radiation • Medical • Occupational • Nuclear Fuel Cycle • Fallout • Petroleum Industries • Power generation • Other
  • 23. Quanties & Units • Amount (activity): – Becquerel (Bq) dis/s – Curie (Ci) 3.7 x 1010 dis/s • Dose: – gray (Gy) 1 J/kg – rad, 0.01 Gy • Dose equivalent
  • 24. Range of Doses General public - 360 mrem/y natural Radon: 200 mrem Other natural: 97 mrem Remainder ~ 15 % medical, 3% products, 1% other Medical procedures (per procedure) CT head and body: 110 mrem
  • 25. %Contribution to Dose • Contribution of various radiation sources to total average dose equivalent to persons in the United States (NCRP, 1987).
  • 26. Basic Facts • Two main types: – electromagnetic (X-rays and gamma rays) – particulate (electrons, protons, alpha particles..) • Produced in the nucleus or through atomic orbital transitions • Capable of ionizing (removing electrons) from atoms
  • 27. Electromagnetic Wavelength Frequency Gamma Rays γ Photon Energy X Rays Ultraviolet Light Visible Light Infrared (heat) radiation Radio Waves
  • 28. Radiation Particles - α α, Helium-4 nucleus (radon is a source) β, nuclear electron (40K is a source) orbital electron
  • 29. Types and properties of ionizing radiation Range in Soft Types of radiation Relative mass & charge Tissue Gamma Ray 0 0 centimeters X-ray 0 0 centimeters Beta Particle (electron) 0.0005 -/+ 1 millimeters 1 0 centimeters Neutron 1 +1 microns Proton 4 +2 microns Alpha
  • 30. Radiation Effects in Living Nuclide decays Emitted radiation ionizes atom OH Free radicals created Cell/DNA attacked Cell killed or damaged dead cell ⇒dead organ damaged cell ⇒cancer(?)
  • 31. Routes of Radiation Exposure External: β, γ, n α, Internal: α, β, γ, n
  • 32. Range of Radiation Hormesis (a little is good for you) Nothing Impaired organ function Cancer Genetic (mutation in offspring) Teratogen (impairment in offspring)
  • 33. Factors Determining Radiation type ( α, β, γ, n ) Duration of delivery (s → y) Location (external or internal) Distribution in / around body Magnitude of dose
  • 34. ‘predicting’ Radiation Effects Why the “uncertainty”? Not all effects are apparent Knowledge limitations (likely impact) Natural variations (radiation field changes) Measurement ability (you can only go so low) Dose is predicted
  • 35. Radiation Effects Model Real data Potential Damage to Health is h es ot yp Doses Causing r H Observed Adverse n ea Li Health Effects 370 mrem 100,000 mrem Area of controversy
  • 36. Radiation Effects Data Mainly for people or lab rats Good data in high dose/high dose-rate region Limited/contradictory data in low dose/low- dose rate region Some data suggest threshold (~10 rem)
  • 37. What about other Insects are tough to kill Big trees are as sensitive as we are So are most mammals Fish and plants are about 10x more resistant But….. radionuclides are “more concentrated” lower in food chain
  • 38. Radiosensitivity of Species Least Most Sensitive Sensitive Micro- organisms Inverte- brates Plants Fish Amphibians Birds Mammals Humans 10 100 1,000 10,000 100,000 1,000,000 Acute radiation dose, rads
  • 39. So...... Radiation in high doses can kill you Radiation in moderate doses increases your cancer risk Radiation at doses near or below background may : do nothing ??? help you ???
  • 40. Should we sink ourselves in ‘the fear’ of technology? Just based on too little knowledge... of we have seen and heard? Nuclear..... “clean technology”, how clean is clean enough? “a little bit of knowledge is a dangerous thing.....”