Jucaian Group
Hi Jucaian Group. Let's start thinking about Nuclear beyond what we learned in class and how it can be used for normal day to day use. I'll comment to you in red once you get going!


Notes on Nuclear Energy:

Source 2:
PROS OF NUCLEAR ENERGY (FISSION):
  • Even after fossil fuels become scarce, nuclear plants will still be capable of producing electricity.
  • Nuclear power plants require less fuel than that of ones which burn fossil fuels.
  • One ton of uranium is capable of producing more energy than several million tons of coal or several million barrels of oil.
  • Fossil fuels contribute to pollution but nuclear power plants do not if run properly.
‍‍‍‍‍‍‍‍‍CONS OF NUCLEAR ENERGY (FISSION):‍‍‍‍‍‍‍‍‍
  • Nuclear Reactor Problems:
    • ‍‍‍Meltdowns‍‍‍: a nuclear reactor disaster where the fission reaction goes out of control - a nuclear explosion results and a great deal of radiation is emitted.
    • Waste disposal problems - ‍‍‍‍‍‍‍‍deadly radioactive waste produced from nuclear reactors is difficult to store safely.‍‍‍‍‍‍‍‍
    • Nuclear reactors have a lifespan of 40-50 years
Source 13
external image storpondthorp.jpg
external image wast4.gif
external image vitrifiedsilos.jpg
NUCLEAR WASTE:
  • Three kinds:
    • Low-level:
      • generated from hospitals, laboratories and industry, as well as the nuclear fuel cycle
      • usually buried in shallow landfills
      • often compacted or incinerated to reduce volume
      • not dangerous to handle
      • paper, rags, tools, clothing, filters w/ small amounts of short-lived radioactivity
      • Worldwide it comprises 90% of the volume but only 1% of the radioactivity of all radwaste.
    • Intermediate-level:
      • may require special shielding
      • resins, chemical sludges and reactor components, contaminated materials from reactor decommissioning
      • Worldwide it makes up 7% of the volume and has 4% of the radioactivity of all radwaste
      • may be solidified in concrete or bitumen for disposal
      • Generally short-lived waste (mainly from reactors) is buried, but long-lived waste (from reprocessing nuclear fuel) is disposed of deep underground.
    • High-level:
      • may be the used fuel itself, or the principal waste that results from reprocessing high-level waste
      • While only 3% of the volume of all radwaste, it holds 95% of the radioactivity
      • contains the highly-radioactive fission products and some heavy elements with long-lived radioactivity
      • generates a considerable amount of heat
      • requires cooling, as well as special shielding during handling and transport
      • if used fuel is reprocessed, the separated waste is vitrified by incorporating it into borosilicate (Pyrex) glass which is sealed inside stainless steel canisters for eventual disposal deep underground
      • if the used fuel is not reprocessed, it is encapsulated for disposal
Source 3:
PROS OF NUCLEAR ENERGY (FISSION):
  • Nuclear power plants emit low levels of CO2.
  • Technology is available - does not need to be developed before use.
CONS OF NUCLEAR ENERGY (FISSION):
  • ‍‍‍Nuclear power plants are potential targets for terrorist attacks - consequences would be deadly‍‍‍
  • ‍‍‍‍‍‍‍‍‍Uranium is a limited resource, and is predicted to run out in the next 30-60 years‍‍‍‍‍‍‍‍‍
  • Takes 20-30 years to plan and build nuclear plants - nearly impossible to build many nuclear plants in a short amount of time.
  • Technically impossible to build a nuclear power plant that is 100% safe
  • Plants become increasingly troublesome as they age
  • Not viewed as a sustainable or renewable resource
Source 12
Costs of Nuclear Energy (details in comment answer)
Source 4:
CONS OF NUCLEAR ENERGY (FISSION):
  • Water resource use - When nuclear power plants remove water from aquatic environments, aquatic life is effected.
  • Polluted with heavy metals and salts, the water discharged from the plant can negatively affect the environment
Source 10
THE PROCESS OF FUSION:
  • Same process that occurs at the core of the Sun
  • Hydrogen nuclei collide to form heavier helium atoms and release enormous amounts of energy into the atmosphere
  • Deuterium-Tritium (D-T) fusion reaction is used to produce energy in a laboratory setting because it produces the highest energy gain at the lowest temperature.
  • At extreme temperatures, electrons are separated from nuclei and a gas becomes a plasma—a hot, electrically charged gas.
  • Fusion reaction will be achieved in a tokamak device that uses magnetic fields to control the plasma
  • Fusion of D-T will produce one helium nuclei, one neutron, and energy
  • Energy produced from neutron is carried away from the plasma and absorbed into the tokamak walls as heat.
  • The heat will be used to produce steam and—by way of turbines and alternators—electricity.
  • No known material can withstand high temperatures of fusion
    • Could possibly work with a powerful magnetic field
    • Would keep hot gases from touching container
    • Currently impractical for continuous fusion reaction
  • Commercially practical fusion reactor will cost billions of dollars, will exist many decades in the future

Source 5:
GENERAL HISTORY:
  • Nineteenth century: Marie Curie studied radiation
  • 1930s: Enrico Fermi studied production of artificial radiation (e.g. aiming neutrons at uranium)
  • Early 1940s: Fermi and other scientists realized chain reaction released a lot of energy
    • Possible military uses
    • Fermi, colleagues, Einstein asked US government for permission to study idea
  • 1942: FDR authorizes "Manhattan Project", Fermi relocated to University of Chicago
  • December 1942: first controlled nuclear chain reaction
  • ‍‍‍‍‍‍‍‍Led to development of atomic bomb; used in 1945‍‍‍‍‍‍‍‍
  • Post-WWII: US creates Atomic Energy Commission
    • Oversee development of nuclear energy
    • Monitor development of nuclear weapons
    • 1950s: AEC works with public utilities to develop peaceful nuclear energy generation
  • During twentieth century: popularization of electricity led to strive to increase efficiency
    • 1960s: electricity efficiency is at a standstill, cost increases
    • Environmental groups began to protest standard methods
    • People turn to nuclear energy
  • ‍‍‍‍‍‍‍Accidents‍‍‍‍‍‍‍
    • Late 1970s: safety regarding earthquakes is of concern to Californians; temporary prohibition (moratorium) of nuclear power
    • 1979: Three Mile Island accident
    • 1986: Chernobyl accident

Source 6:
  • There are 56 countries that operate 180 nuclear power reactors that are used to power over 140 ships and submarines, used in the Navy
  • Provide about 14% of the world's electricity
  • 14 countries depend on nuclear power for at least a quarter of their electricity (Belgium, Bulgaria, France, Hungary, Czech Republic, Slovakia, South Korea, Sweden, Switzerland, Slovenia, Ukraine, Japan, Germany, and Finland)
  • Nuclear reactors cause electricity production to rise
  • U.S generates 99,210 MW of electricity, the most out of any country

Source 7:
  • Nuclear applications are used to sterilize medical supplies, and to toughen rubber in automobile tires
  • ‍‍The IAEA wants to try to use nuclear techniques to address problems in the world, such as world hunger.
    • IAEA has been trying to make crops that are resistant to drought‍‍
    • They also are trying to make the crops more nutritional for the malnourished people in parts of Africa

Source 8:
THREE MILE ISLAND:
  • Near Middletown, PA; March 28, 1979
  • Most serious commercial nuclear power plant accident in the US
  • No deaths or injuries of workers or community members
  • Resulted in changes to nuclear industry regulations
  • US Nuclear Regulatory Commission tightened oversight
  • Partial meltdown of TMI-2 reactor core
  • Small releases of radioactivity; off-site
  • Sequence of events:
    • 4:00 AM: main feedwater pumps stop working in non-nuclear portion of plant (either a mechanical or electrical failure)
    • Turbine, reactor shut down
    • Pressure in nuclear (primary) portion of plant begins to increase
    • Pilot-operated relief valve opens at top of pressurizer to lessen pressure
    • Signals to operator failed to indicate that valve was still open
    • Valve remained stuck open, coolant poured out of it
    • Reactor core overheated
  • Problems:
    • No instrument showed coolant levels in core
      • Operators judged core coolant levels by pressurizer coolant levels
      • Pressurizer coolant level was fine due to open valve, so operators thought situation was fine
    • No signal that relief valve was open
    • Alarms and bells rang, but operators did not realize it was a loss-of-coolant incident so they took the worst possible route and further decreased the amount of coolant directed towards the core in an attempt to solve the problem
  • Although severe core meltdown, containment building walls not breached
  • Aftermath:
    • NRC (US Nuclear Regulatory Commission) notified promptly; by midday, radioactivity had been sampled, non-essential personnel ordered off-site; by evening, adequately cooled, reactor stable
    • March 30: release of radiation to relieve pressure causes confusion
    • Presence of hydrogen bubble causes concern; on April 1deemed unable to burn or explode, size significantly decreased
    • Most radiation contained; released radiation had almost no effect on health of nearby people
  • Some resulting changes to industry:
    • Improved plant, equipment requirements: fire protection, piping system, isolation of containment building, reliability of components increased, automatic shutdown feature added
    • Tightening of requirements for staff
    • Improved controls for operating plant, interpreting signals
    • Improved means of notifying NRC; establishment of NRC operations center open 24 hours a day
    • Establishment of a report where the NRC could report findings


PICTURES:
http://www.npr.org/news/graphics/maps/three_mile.jpg
external image three_mile.jpg

http://chemcases.com/2003version/images/image42.jpg

image42.jpg

Screen_shot_2012-03-07_at_7.08.45_PM.png


Source 9:
Fukushima Daiichi Nuclear Disaster
  • Occurred after series of equipment failures, nuclear meltdowns, and release of radioactive materials. All following an earthquake and tsunami on March 11, 2011
  • After the earthquake, emergency reactors were put on. Tsunami then cause the reactors to overheat
  • This led to a 20km radius evacuation around the plant.
  • Total amount of radioactivity that was released was approximately one-tenth the amount that was released in the Chernobyl incident

Source 11:
  • Nuclear transport
    • Ships and submarines use Nuclear based propulsion.
    • Helps submarines stay underwater for a long period of time
  • Medical Applications
    • Used in X-rays, external radiation therapy and chemotherapy
    • Can be used to analyze the kidney function, scan the blood flow to the heart, scan the lungs to find and assess respiratory problems, identify infections, and identifying abnormalities in the kidneys, esophagus, and intestines
  • Space and Futuristic Applications
    • Nuclear fission can generate infinite amounts of energy at a low cost
    • Fission reactors help power rockets and space vehicles
  • Food and Agriculture
    • SIT is a technique used to sterilize male insects
    • Exposure to gamma radiation before they hatch sterilizes them, so they can't produce offspring

Source 14:
The Extraordinary Chemistry of Ordinary Things by Carl H. Snyder
NUCLEAR POWER PLANTS:
  • Fission reactor built around nuclear pile (core)
  • Fission heat converts water to steam
  • Steam strikes turbine blades
  • Attached to electric generator
  • Control rods slide into and out of core to control energy production rate

SOME HISTORY:
  • Fermi's research meant to encourage further research, not actual production of power
  • December 1951: first time electricity is generated on a large scale by fission; by Nation Reactor Testing Station in Idaho
  • 1970: 18 nuclear plants in US, 1.4% of energy in US
  • 1988: 108 nuclear plants in US, 11% of energy in US
  • 2000: 104 nuclear plants in US, 20% of energy in US; 438 in world, 31 planned
In 2000:
Country
Nuclear Power Plants in Operation
Percentage of Electric Power Produced
United States
104
20
France
59
76
Japan
53
34
United Kingdom
35
22
Russia
29
15
Germany
19
31



Drs. Cai, Freedman, and Gong: You have the advantage that most people have heard of nuclear energy for use in power, but there have been a lot of bad connections with nuclear energy in terms of accidents and weaponry. How do you plan to conteract the public opinion and "knowledge" about the safe use of your energy source? You need to address the storage, implementation, and availability use including safe transportation of the nuclear material. You also need to see how the needs of the consumers can be met and consider a future plan, especially as you note that a number of the reactors are aging and may be taken off-line and that there is a time lag to building new reactors.

  • education
  • explanation of tightened safety protocol since incidents in the past
  • other types of energy may rise to increased prominence while reactors are upgraded/rebuilt