Nuclear energy
Download
1 / 32

Nuclear Energy - PowerPoint PPT Presentation


  • 265 Views
  • Updated On :

Nuclear Energy. A. What does radioactive mean?. Radioactive materials have unstable nuclei, which go through changes by emitting particles or releasing energy to become stable Call this nuclear decay . B. Types of Radiation.

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'Nuclear Energy' - vail


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.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript

A what does radioactive mean l.jpg
A. What does radioactive mean?

  • Radioactive materials have unstable nuclei, which go through changes by emitting particles or releasing energy to become stable

    • Call this nuclear decay


B types of radiation l.jpg
B. Types of Radiation

  • Nuclear Radiation: the particles that are released from the nucleus during radioactive decay

    • When a radioactive nucleus decays, the radiation leaves the nucleus

    • This may form an isotope of the same element or make a new element


Types of radiation l.jpg
Types of radiation

  • 1. Alpha particle

  • 2. Beta particle

  • 3. Gamma ray

  • 4. Neutron


Slide5 l.jpg



Slide7 l.jpg

  • Beta Particle: a negatively (-) charged electron emitted during radioactive decay

    • Fast-moving electron- MADE FROM A NEUTRON THAT DECAYS & FORMS A PROTON AND A e-

    • THE PROTON STAYS AND THE e- LEAVES THE ATOM

    • Can penetrate sheet of paper, but stopped by 3 mm of aluminum

    • Symbol: 0-1e



Slide9 l.jpg

  • Gamma Rays: high-energy radiation emitted during radioactive decay and nuclear fission

    -Marie Curie- isolated radium & saw it emitted gamma rays

    • Gamma rays are a form of electromagnetic energy so they are “not charged” and “not made of matter”

    • Not stopped by clothing or most building materials, (can penetrate up to 60 cm of Al or 7 cm of Pb) so are much more dangerous

    • Symbol: γ


Gamma rays l.jpg
Gamma Rays decay and nuclear fission


Neutron emission l.jpg

No charge; decay and nuclear fission

Need 15 cm Pb to stop fast moving neutrons

Neutron Emission


Nuclear decay l.jpg
Nuclear Decay decay and nuclear fission

  • When an unstable nucleus emits alpha or beta particles; # of P & # N changes

  • Alpha Decay- lose 2 P + 2 N (same as He atom)- causes the mass number to decrease by 4 & the atomic number to decrease by 2

  • Example: The process of alpha decay of radium-226 is written as follows.

    22688Ra → 22286Rn + 42He


Nuclear decay13 l.jpg
Nuclear Decay decay and nuclear fission

  • Beta Decay- gain 1 P + lose 1 N (remember a neutron decays to form 1 P & 1 e- (the proton stays and the e- leaves)

  • Example: Carbon-14 decays to nitrogen-14 by emitting a beta particle

  • 146C → 147N + 0-1e

  • Gamma Ray decay- no change in # P; energy content changes in the matter it hits


C decay rates l.jpg
C. Decay Rates decay and nuclear fission

  • Half-life: time required for half of a sample of radioactive substance to decay

    -1st half life = ½ sample remains

    -2nd half life = ½ x ½ = ¼ sample remains

    -3rd half life= ½ x ½ x ½ = 1/8 sample remains

    2. Use these decay rates to tell the age of rocks and fossils (radiometric dating)

    • Carbon-14 is common isotope used in radiometric dating


Nuclear reactions l.jpg
Nuclear Reactions decay and nuclear fission

  • Strong Nuclear Force- force that causes protons & neutrons to attract each other in the nucleus

  • Protons are + and repel each other

  • Neutrons have no charge so they help create the strong nuclear force to hold protons & neutrons together in the nucleus


Nuclear reactions16 l.jpg
Nuclear Reactions decay and nuclear fission

  • Stable Nuclei- strong nuclear force is stronger than the repulsion force

  • Unstable Nuclei- strong nuclear force is less than the repulsion force

    A. Have too many or too few neutrons in

    nucleus

    B. Have more than 83 protons in nucleus

    C. Will decay (and release radiation) into a

    more stable nucleus


Ii nuclear reactions l.jpg
II.) Nuclear Reactions decay and nuclear fission

A) Nuclear Fission: the process by which a nucleus splits into two or more smaller atoms and releases neutrons and energy

  • In nuclear fission, tremendous amounts of energy can be produced from very small amounts of mass (Fig. 7 p.295)


Nuclear fission l.jpg
Nuclear Fission decay and nuclear fission

  • 23592 U + 10n → 13756 Ba + 8436 Xe + 15 10n + energy


Slide19 l.jpg

  • Converting Mass into Energy decay and nuclear fission

    • Albert Einstein introduced the mass-energy equation:

      E = mc2

    • According to the law of conservation of mass and energy, the total amount of mass and energy remains constant

    • Mass defect- the total mass of any nucleus measured is less than the sum of the individual masses of protons & neutrons that form it; SOME OF THE MASS HAS TURNED INTO ENERGY!!


Converting mass into energy l.jpg
Converting Mass into Energy decay and nuclear fission

  • The amount of energy released during nuclear fission is related to the mass that is turned into energy

  • E = mc2


Slide21 l.jpg

  • Triggering a Nuclear Chain Reaction decay and nuclear fission

    • Nuclear fission follows a pattern of a chain reaction; The speed of a chain reaction can vary

    • Chain reaction: a continuous series of nuclear fission reactions [Fig 8 p.296]

    • Nuclear fission releases more neutrons which trigger more fission reactions

    • The number of neutrons released determines the success of a chain reaction


Nuclear chain reaction l.jpg
Nuclear Chain Reaction decay and nuclear fission


Slide23 l.jpg

  • Nuclear weapons decay and nuclear fission- ex. Atomic bombs (use U-235 or Pu-239) are designed to have an uncontrolled chain reactions

  • Nuclear Power Plants- A controlled chain reaction, heat from the reaction can be used to generate electrical energy

    -controls chain reaction with control rods that absorb neutrons emitted after fission reaction

  • Critical Mass: the minimum amount of a substance that can undergo a fission reaction and can also sustain a chain reaction.


Slide24 l.jpg

  • Nuclear Energy From Fission decay and nuclear fission

    • Nuclear power plants generate about 20% of electricity in the U.S.

    • Controlled fission of uranium-235 in a fission reactor

    • Don’t emit air pollutants, but have other safety concerns

    • 1986: meltdown of reactor at Chernobyl nuclear power plant in Ukraine


Slide25 l.jpg

  • Fusion decay and nuclear fission: the process in which smaller nuclei fuse together at extremely high temperatures and release energy (occurs in stars like the sun)

  • Light nuclei combine to form heavy nuclei

    • In nuclear fusion, tremendous amounts of energy can be produced from very small amounts of mass

    • THE FUSION OF HYDROGEN RELEASES MORE ENERGY THAN THE BURNING OF NATURAL GAS, BURNING OF COAL, OR THE FISSION OF URANIUM-235!!


Fusion l.jpg
Fusion decay and nuclear fission

  • Nuclear fusion plants using hydrogen may be a possibility one day

  • 1 pound of hydrogen in a fusion reactor may release as much energy as 16 million pounds of burning coal!!


Slide27 l.jpg

Fusion Reaction decay and nuclear fission

. 2H + 3 H  4He + 1n

1 1 2 0


Slide28 l.jpg


Slide29 l.jpg


Nuclear radiation today l.jpg
Nuclear Radiation Today of 10,000,000

  • Background Radiation- all around us; comes from natural sources like the sun, plants, water, heat, soil, rocks, etc. ( due to the fact that radioactive isotopes live there)

  • Exposure varies from one location to another

  • ex. Living in higher altitudes or around rocks increases radiation exposure

  • -Also, things like smoking, getting x rays


Beneficial uses of radiation l.jpg
Beneficial Uses of Radiation of 10,000,000

  • 1. Smoke detectors- release alpha particles which are charged & release an electric current, smoke decreases the flow of current which sets off the alarm

  • 2. Used to detect disease-

  • A). X-rays

  • B). MRI

  • C). Radioactive tracers- isotopes that

    concentrate in affected areas to locate tumors


Nuclear radiation is used to treat cancer l.jpg
Nuclear Radiation is used to treat cancer of 10,000,000

  • Radiotherapy- is a treatment that uses controlled doses of nuclear radiation for treating diseases such as cancer

  • Ex. A) Brain tumor- uses gamma rays to treat

    them

  • B) iodine isotopes treat thyroid cancer

  • C) Radiation is used to kill defective bone

    marrow of leukemia patients

  • Agriculture- radioactive tracers move through crops to see how fast water moves through them.


ad