1 / 63

Nuclear Energy

Nuclear Energy. Could have ignited atmosphere & blow up Government documents- Since 1957 facilities had released material into air, & water w/o telling people. Was believed to be a source of unlimited energy So much we would not need to measure the amount.

nibaw
Télécharger la présentation

Nuclear Energy

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Nuclear Energy • Could have ignited atmosphere & blow up • Government documents- Since 1957 facilities had released material into air, & water w/o telling people. • Was believed to be a source of unlimited energy • So much we would not need to measure the amount

  2. An atom consists of a nucleus surrounded by electrons. • The electrons are negatively charged.

  3. The atom is held in place by an electric force of attraction between the positively charged protons and negatively charged electrons. • The nucleus contains two types of particles: protons and neutrons.

  4. An atom that has more or less protons than normal or found in nature is called an isotope. • The force of attraction between the protons and neutrons is called the strong force.

  5. Nucleons- the particles in the nucleus of the atom (protons & neutrons) • Strong nuclear force- acts on subatomic particles to hold the nucleus together • overcomes electrostatic repulsion between protons

  6. To remove a proton or neutron from the nucleus of an atom, we must have a force that is greater than the strong force and therefore, work is required. • The amount of work required to remove a proton or neutron is called the binding force.

  7. Atom- the material stuff is made from- about 105 element • Transmutation- the changing of one element to another • Transuranium elements- 93 and greater radioactive

  8. Radioactivity- spontaneously decompose • Radiation- penetrates biological tissues- leaves no marks, can’t be felt. It breaks down molecules in cells • Background radiation is always present

  9. Radioisotopes, . isotopes of atoms with unstable nuclei, emit radiation to attain more stable atomic configurations.

  10. A positively charged electron is called a positron and can be found in beta radiation. • A positron is also known as an antiparticle or a particle of antimatter.

  11. positron emission- radioactive decay process involving emission of a positron • electron capture- occurs when the nucleus of an atom draws in a surrounding electron- usually from the lowest energy level

  12. The uranium-238 decay series • one of three series in which a radioactive isotope having a long half-life undergoes a series of natural radio-active changes and ends as a stable lead isotope.

  13. primary types of radioactive decay. • Alpha = 42 He • Beta = 0-1e • Hydrogen = 11 H • Neutron = 10n • positron emission= 01 • electron capture = X-ray photon • gamma emission 00γ

  14. Unstable protons and neutrons that emit radiation are called radioactive. • Alpha and Beta are made up of particles while gamma is made up of energy.

  15. Theses nuclear chain reactions are self sustained which means they do not need additional energy once the reaction is started. • These nuclear chain reactions is what makes nuclear reactors and bombs.

  16. When neutrons split into smaller particles it is called fission. • When one neutron splits it bumps into other neutrons and causes them to split. This is called a Nuclear Chain Reaction.

  17. The radiation emitted during nuclear disintegration is of three types: radiation may be • alpha (positively charged helium nuclei) & Will ionize gas; 1/10 speed of light • beta (electrons), Will ionize gas; approaches speed of light • gamma (electromagnetic radiation). Will ionize flesh, speed of light

  18. Radiation- continuously decay to form new elements- giving off high-energy radiation. • Ionizing- injure atoms (body may repair or illnesscancer or genetic defects • Ionizing Radiation- Radiation which causes the things which come in contact with radiation to become radioactive. • Non-ionizing Radiation-do not cause surrounding things to become radioactive

  19. Geiger Counter Demo • Geiger counters • scintillation counters • and film badges • used to detect & measure radiation

  20. Geiger Counter- • particles in tube are ionized by radiation striking them. The more radiation, the more ionization and the stronger the current which flows through the tube. A counter produces clicks as indicator of theradiation around

  21. Measuring Radioactivity Electroscope Cloud Chamber- alcohol in container with dry gas- ions formed (alspha produce a visible track in the cloud chamber • detects electric charge- leaves repel when charged radiation causes charged air (ionization)

  22. Bubble Chamber- • liquid hydrogen at its boiling temp with reduction in pressure cause bubbles to appear along the parth of the particle. Condensation trails- (like path of jet air craft) are formed.

  23. Damage is dependent on • the type of cell and tissues- somatic/germ, thyroid/hands • type of rad.-alpha, beta, gamma • area or volume involved • total dose & energy of radiation • time for the accumulation of the dose

  24. When exposed to radiation • Somatic- (body cells) may cause cancer • Germ cells-(egg & sperm) affect the formation of children. Birth Defects

  25. Rad- measure of radiation dosage Rem- measure of the effect on humans Rem-Based on dosage and damage. Rem-Rads X Biological =Damage Factor

  26. Human Effects of Radiation

  27. Radioactivity & radiation • used in agricultural research • in medical diagnosis • treatment some diseases.

  28. Tracers- radioactive material whose path may be followed • Detect ground water movement through soil • paths of industrial pollutants in air & water • shifting of sand along coastline • test of durability of components & ID structural weaknesses of equipment • medicidne- diagnosis & treatment • irradiation of food-long term storage w/o refrigeration (kills bacteria & molds which cause spoilage.

  29. Photosynthesis • Green plants absorb carbon in the form of carbon dioxide. A % of this is C-14. Once the plant dies, the photosynthesis stops and no more CO2 is absorbed. The decay of C-14 continues. By measuring the amount of radioactivity of C-14 a once-living plant yields- its age can be determined. The half-life of C-14 is 5700 yrs.

  30. Radioisotope target organ • Chromium 51 spleen • Iodine 131 thyroid gland, lungs, kidneys • gallium 67 lymph glands • selenium 75 pancreas • technetium 99 brain, lungs, liver, spleen, bones

  31. Iron -59 used to produce this image of a patient’s circulatory system

  32. PET- • positron emission tomography- expensive- requires radionuclides w/short half-lefes • must maintain a cyclotron to produce as needed

  33. Medical diagnostics SPECT- MRI Magnetic Resonance Imaging • single photon emission computed tomography diagnose malfunctions more accurately than X-ray move common place than PET

  34. The age of the earth is determined by measuring the quantity of uranium-238 and of lead or helium found in minerals. . • The amounts of carbon-14 and carbon-12 found in organic remains are used to estimate their ages up to 60 000 years.

  35. Nuclear fission • A neutron strikes U-235, splitting it & forming new elements -releasing several neutrons causing a chain reaction & releases a lot of energy .

  36. Chain reaction half-life .the time required for half the atoms in a radioactive sample to decay. Every radioisotope has a characteristic half-life. • a domino effect • because fuel is not pure enough

  37. critical mass • the amount of a fissionable material that will support a self-sustaining chain reaction

  38. Nuclear reactors • use nuclear fission to generate steam. • steam is used to drive turbines that produce electrical power.

  39. Types of Reactors • Fission-Fuel-Uranium/Plutonium byproduct-radiation • Fusion- Fuel = Hydrogen, Byproduct =helium(inert, nonradioactive) • Breeder- creates more fuel than it consumes

  40. Nuclear fission • the splitting of a heavy atom like Uranium or Plutonium. • One pound(U-235)=1000 tons coal

  41. Problems • Needs tritium (radioactive), which is not abundant and difficult to contain. • It causes embrittlement • High Thermal Pollution

  42. Functioning of a Nuclear Power Plant • Core- contains of fuel rods packed with U-235 as the fuel • Control rods- of cadmium or boron- absorb neutrons & regulate reaction • Moderator- water, graphite or heavy water is used to slow down the neutrons emitted by the fission process

  43. Functioning of a Nuclear Power Plant • Coolant- usually water- removes heat to keep the fuel rods and other materials from melting

  44. Embrittlement Decommissioned the shutting of a plant down by sealing the entire containment building for an indefinite period of time. • - the metals making up the nuclear power plant become brittle because of neutron bombardment and makes it unsafe

  45. China Syndrome • - a loss of coolant accident- After 45 sec, the core temperature will rise to 1480 degrees C. • It can react to produce • Hydrogen gas -explosive.

  46. Nuclear Waste • no safe method of long term disposal and no permanent disposal site in the U.S. • used to produce nuclear weapons • we purchase it from other countries.

More Related