Radiation ENGR 302 I Electromagnetic Radiation n

Radiation ENGR 302 I

Electromagnetic Radiation n n Radar, radio, and TV (transparent) Microwave (Rotation of molecule) Visible, UV (Vibration, absorbed by skin) X-ray and gamma-ray (Ionization, nearly transparent, but highly energetic)

Ionizing Radiation n Ionizing radiations are: n n n X-ray Alpha particles (helium nuclei) Beta rays (electrons) Gamma rays Neutrons and Protons Effects on humans are: n n Damage DNA Interference with normal cells

Half-Life n Half Lives n n n Uranium-235 Plutonium-239 Cesium-137 Strontium-90 Iodine-131 0. 7 billion years 24, 360 years 30 years 28. 8 years 8. 04 days • N/N 0=1/1, 000 10 half-lives • N/N 0=1/1, 000 20 half-lives • N/N 0=1/1, 000, 000 30 half-lives

Biological Half-life n Radioactive material within a living cell: n n n Isotope iodine-125 n n n Radioactive decay Normal biological decay Non-biological half-life Biological half-life 60 days 38 days Isotope carbon-14 n n Half-life 5000 years (essentially constant during one’s life time. Carbon-dating

Units of Radiation n Source n n Absorbed n n Becquerel, Curie rad (radiation adsorbed dose) Human Biological Damage n n rem (roentgen equivalent man) For x-ray and gamma-ray 1 rem=1 rad

Nuclear Waste Depositories n n n Permanent subterranean Entombment under the sea Nuclear transmutation Storage under polar caps Other less serious proposals

Permanent Storage n Storage sites must be n n n Geographically stable with no flowing ground water for tens of thousands of years 100 sites are designated as “temporary” storage sites Permanent site (2010)– Yucca Mountain (Nevada – Near a young volcano and active fault line), Carlsbad (New Mexico Oozing brine could cause steel brines to corrode) Transporting nuclear wastes to these facilities is also a problem NIMBY Syndrome Listen to NPR’s All Things Considered 2/22/02 NPR 2/5/02

Atom Bomb

Hydrogen Bombs n n Isotopes of hydrogen and deuterium are fused to produce helium No limits to the explosive power n n US tested one with the explosive power of 68, 000 tons of TNT Consequences are horrifically unclear n Nuclear Winter, Worldwide famine

Weapon Design n Conventional vs. Nuclear Bombs n The A-Bomb n n Critical mass Dirty Bombs Depleted Uranium The H-Bomb (thermonuclear) n n Neutron Bombs Thermonuclear Bunker Busters

1 -Megaton Blast Distance from Ground zero n 1 mile • • • n 2 miles n • • n Over-pressure: 17 psi Winds: 400 mph Humans battered to death; lung hemorrhage; eardrums ruptured; Heavy machinery damaged 5 miles n • • n Over-pressure: 43 psi Winds: 1700 mph Many Humans Killed Over-pressure: 4 psi Winds: 130 mph Bones fractured; All trees down; Buildings flattened 20 miles n • • Over-pressure: Below 1 psi Winds: Below 35 mph Many broken windows

Effects n Short term (somatic, massive , direct) n Fast growing cells are most susceptible to ionizing radiation n n Effects are n n Bone marrow cells (making blood cells) Ovaries, testes, lenses of the eyes Cancer cells grow faster than normal cells so they are treated with radiation Reddening of the skin, drop in the white blood cells, nausea, vomiting, hair loss, bleeding, and death Long term (chronic, low dose, indirect) n Chromosome (DNA) damage - cancer

Nuclear Arm Treaties Listen to NPR’s all thing Considered 2/22/02 Listen to NPR’s all thing Considered 5/13/02

Sources of Exposure n n Non-ionizing radiation n Natural n UV from the sun n Man-made n UV from tanning machines Ionizing radiation n Natural n Intercontinental flights (cosmic rays) n Soil and rocks n Radon (radioactive decay of uranium in soil) Man-Made n Dental and chest x-rays n Nuclear Medicine (Cobalt-60) n Nuclear reactors n n High frequency UV

Consequences of Nuclear Wars… n n n Shock Effects Thermal Effects Radiation Effects

Nuclear Agency n n US Department of Energy (Do. E) n Nuclear Weapons Research n Licensing the nuclear reactors n Nuclear Waste US Environmental Protection Agency (EPA) n Set exposure limits and standards n Cleanup of contaminated areas US Nuclear Regulatory Commission (NRC) n Source material (uranium and thorium) n Enriched material (enriched uranium, , plutonium) n Dose limits for radiation medicine n Implementing EPA Standards UN International Atomic Energy Commission (IAEC) n n n Verify through inspection that States comply with their commitments under the Non-Proliferation Treaty. Nuclear Technology Transfer Assist members in the planning peaceful nuclear programs

Public Exposure n n Background Medical Radon Nuclear reactors 100 mrem 50 mrem 200 mrem 10 mrem Total 360 mrem Ref: Nuclear Regulatory Commission

How much radiation do you receive? To a good approximation you can estimate the amount of radiation you receive every year from various sources. Here is how to estimate: 1. Where do you live? _____ Elevation* (meters) _______ Cosmic radiation Sea level 28 mrem Elevation X 0. 015 Terrestrial If you live within 10 km of a nuclear or coal power plant, add 0. 3 _______ 2. What is your house made of? Brick or concrete (add 70), wood (add 30) _______ 3. Ground radiation (US average) 26 mrem Radon ( Water, food, and air (US average) 28 mrem Watching TV 1 mrem 4. How many miles are you flying every year? Number of miles ______ x. 001 _______ 5. How is your health? Number of chest x-ray _____ x 40 _______ Number of dental x-ray _____ x 5 ____ Number of mammogram _____ x 30 _______ Others (chemotherapy) _______ TOTAL _______

Exposure Limit (EPA/NRC) n n 125 mrems every three months (500 mrems per year) Higher for nuclear reactor personnel (5000 mrem per year)

American Guinea pigs n n In 1986, The Between 1940 and 1970, the US Government conducted radiation experiments on 695 human subjects without their knowledge. In 1994, Energy secretary Hazel O’Leary declassified millions of pages of documents. As a result n n n Congress approved Radiation Exposure Compensation Act ($50, 000 for residence who lived downwind from certain nuclear tests and later developed cancer) $75000 for soldiers who developed cancer after participating in above ground nuclear war tests $150, 000 for residents of Martial Islands who became ill after 1940 s-1950 s tests

Regulation (Continued) n 1980 – Low-Level Radioactive Waste Policy Act n n “Encourages” neighboring states to cooperate on reaching agreement on waste disposal in their “compact” and choose appropriate sites for disposal. 1985 – Nuclear Waste Policy Act n Disposal of high-level nuclear waste is at the hands of Federal Government, while authorizing states and Native American tribes to participate n the selection of appropriate permanent repository site.

Internet Resources n Radiation and Health Physics (www. sph. umich. edu/group/eih/UMSCHPS/Sources. htm) Nuclear Regulatory Commission (www. nrc. gov)