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Do Now:. How many Joules are required to get from Newburgh to Mahopac? Newburgh  Mahopac 33 miles Driver input 6530 BTUs/person/mile 1 BTU = 1000 (1x10 3 ) Joules 1 kJ = 1000 (1x10 3 ) Joules. Do Now: ANSWER. How many Joules are required to get from Newburgh to Mahopac?

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do now
Do Now:

How many Joules are required to get from Newburgh to Mahopac?

  • Newburgh  Mahopac 33 miles
  • Driver input 6530 BTUs/person/mile
  • 1 BTU = 1000 (1x103) Joules
  • 1 kJ = 1000 (1x103) Joules
do now answer

How many Joules are required to get from Newburgh to Mahopac?

  • 33 miles X 6530 BTUs/1 person/mile= 2.1x105 BTUs/person
  • 2.1x105 BTUs/person X 1x103 joules/1 BTU

=2.1X108 Joules/person

nuclear energy
Nuclear Energy
  • In contrast to a chemical reaction, a nuclear reaction involves changes within the nuclei of an atom.

Valence Electrons

http://www.Chemicool Periodic


Nuclear Energy

  • Small amounts of matter = large amounts of energy.
nuclear reactions produce 100 000 times more energy per atom than chemical reactions

Nuclear Energy

Nuclear reactions produce 100,000 times more energy per atom than chemical reactions.

nuclear weaponry releases this energy all at once
Nuclear weaponry releases this energy all at once.

A 23 kiloton tower shot called BADGER, fired on April 18, 1953 at the Nevada Test Site, as part of the Operation Upshot-Knotholenuclear test series.

the 1945 trinity nuclear explosion
The 1945 TRINITY nuclear explosion.
  • May 7, 1945
  • The first nuclear explosion in history took place in New Mexico, at the Alamogordo Test Range, on the Jornada del Muerto (Journey of Death) desert, in the test named Trinity.
  • The heat of the Trinity explosion melted the sandy soil around the tower to form a glassy crust known as "trinitite".
isotopes of hydrogen
Isotopes of Hydrogen
  • Deuterium: 1 proton and 1 neutron (hydrogen usually has no neutrons).

radio isotopes
Radio Isotopes
  • These are unstable isotopes and are referred to as radioactive.
  • They spontaneously emit radiation.
Radiation: particles or rays of energy that result from the decay of a nucleus of a particular element into that of another element.
radioactive decay
Radioactive Decay
  • Uranium 235 (U 235) decays into Lead 207 (Pb 207)

radioactive half life
Radioactive Half-Life
  • The period of time required for one half of the total amount of a radioactive substance to change into a different element.
nuclear fuel cycle
Nuclear Fuel Cycle
  • The processes involved in producing the fuel used in nuclear reactors (Uranium ore) and in disposing of radioactive wastes. (nuclear waste)
nuclear fuel cycle1

Nuclear Fuel Cycle

Not taking place


Uranium ore needs to be refined through enrichment to obtain approximately 3% U 235Uranium ore has approximately: 0.71 % U 2350.01 % U 23499.0 % U 238

nuclear reactors
Nuclear Reactors
  • Uranium pellets are used to obtain energy (uranium dioxide.)
  • Each pellet is equivalent to the energy found in a ton of coal (2000 1bs).

uranium enrichment
Uranium Enrichment
  • To make fuel for reactors, the natural uranium is enriched to increase the concentration of U235 to 3 percent to 5 percent.
  • The uranium fuel cycle begins by mining and milling uranium ore to produce Triuranium octaoxide (U3O8), also known as "yellow cake," which is then converted into uranium hexafluoride (UF6).
  • The UF6 is then enriched before being made into nuclear fuel.
  • Throughout the global nuclear industry, uranium is enriched by one of two methods:
    • gaseous diffusion
    • gas centrifuge
    • A third method – laser enrichment – has been proposed for use in the United States.

nuclear fuel cycle2
Nuclear Fuel Cycle
  • Pellets are inserted into fuel rods (12 ft long) which are grouped into fuel assemblies (200 rods/assembly)
do now identify the following reactions
Do Now:Identify the following reactions
  • 4 1n + 127 I  131 I ____________

(atomic #53 iodine)

2. 238U  234 Th + 4 He___________

  • 234 Th  234Pr + e ____________

(atomic #59 praseodymium)

4. 1n + 235Ur  97 Kr + 141 Ba 3 1n __________

5. 2H + 2H  4He ____________

do now answers identify the following reactions
Do Now: ANSWERSIdentify the following reactions
  • 4 1n + 127 I  131 I Neutron capture

(atomic #53 iodine)

2. 238U  234 Th + 4 HeAlpha Decay

  • 234 Th  234Pr + e Beta decay
  • 1n + 235Ur  97 Kr + 141 Ba 3 1nFission
  • 5. 2H + 2H  4He Fusion

nuclear reactors1
Nuclear Reactors
  • Most reactors contain 250 assemblies.
  • U235 is bombarded with neutrons which causes a fission reaction (splitting) of the nucleus.
nuclear reactors2
Nuclear Reactors
  • This initial splitting frees up additional neutrons which then bombard more U 235 nuclei which frees more neutrons which splits more U 235 nuclei...
  • This is called a chain reaction or “cascade effect.”
nuclear fission

Nuclear Fission

nuclear reactors consist of
Nuclear Reactors Consist of ...

1 ) Reactor core: Fission takes place heat.

2) Steam Generator: heat from reactor core produces steam.

3) Turbine: steam spins the turbine to generate electricity.

4) Condenser: cools the steam back to liquid water.

reactor core
Reactor core
  • Fission takes place here.
  • This area contains the fuel assemblies.
  • Each assembly has a control rod which absorbs neutrons.
  • By lowering and raising the control rod an operator can control the rate of the fission reaction.

Water Circuits

Primary circuit: heats water to 293 °C (which is 560°F), using the energy from the fission reactor.High pressure keeps the water in liquid form.


Water Circuits

Secondary circuit: boils water to steam and then converts back to liquid. Turbine is spun due to steam and change in pressure from cooling.


Water Circuits

Tertiary circuit: provides cool water to the condenser (which cools the spent steam in the secondary circuit).As this water is heated, it is transferred from the condenser to the cooling tower (“lake").Once cool, the water is sent back to the condenser.


Secondary circuit

Primary circuit

Tertiary circuit

nuclear reactors in the us
Nuclear Reactors in the US

safety nuclear energy
Safety& Nuclear Energy
  • Nuclear reactors contain huge steel structures called reactor vessels that will prevent the release of radiation leaks.
  • This vessel is placed in a containment building which is an additional precaution to prevent radiation leakage. (Earthquake, tornado, & "plane proof“ steel reinforced concrete walls 3-5 ft. thick.)




  • The Chernobyl accident in 1986 was the result of a flawed reactor design that was operated with inadequately trained personnel and without proper regard for safety.
  • The resulting steam explosion and fire released at least five percent of the radioactive reactor core into the atmosphere and downwind.
  • 28 people died within four months from radiation or thermal burns
  • 1999 Ukranian health minister reported the death toll was nearly 170,000
  • 400,000 adults, 1 million children receiving govt aid for health
  • Inc in birth defects, infant leukemia, immune abnormalities
  • Preparing for an increase in adult cancers roughly 29 years later

  • On 25 April, prior to a routine shut-down, the reactor crew at Chernobyl-4 began preparing for a test to determine how long turbines would spin and supply power following a loss of main electrical power supply. Similar tests had already been carried out at Chernobyl and other plants, despite the fact that these reactors were known to be very unstable at low power settings.
  • A series of operator actions, including the disabling of automatic shutdown mechanisms, preceded the attempted test early on 26 April. As flow of coolant water diminished, power output increased. When the operator moved to shut down the reactor from its unstable condition arising from previous errors, a peculiarity of the design caused a dramatic power surge.
  • The fuel elements ruptured and the resultant explosive force of steam lifted off the cover plate of the reactor, releasing fission products to the atmosphere. A second explosion threw out fragments of burning fuel and graphite from the core and allowed air to rush in, causing the graphite moderator to burst into flames.
  • There is some dispute among experts about the character of this second explosion.  The graphite - there was over 1200 tones of it - burned for nine days, causing the main release of radioactivity into the environment

  • Some 5000 tones of boron, dolomite, sand, clay and lead were dropped on to the burning core by helicopter in an effort to extinguish the blaze and limit the release of radioactive particles.
  • Local lands decontaminated
  • Radioactive soil removed
  • Roads and buildings scrubbed
3 mile island
3 Mile Island
  • Mar. 28, 1979
  • 50% meltdown of the reactor core
  • no immediate deaths.
  • The cleanup cost more than $1.5 Billion.
  • Located 10 miles southeast of Harrisburg PA on the Susquahanna River.
  • The accident began in the early morning of March 28, when a little after 4:00 AM, pumps supplying water to TMI-2's steam generators tripped.  With no water, there would be no steam, and therefore the plant's safety system kicked into action and shut down the steam turbine and the generator it powered.  The nuclear reactions in the core continued until the system dropped the control rods into the core to halt the fission process, which is a process called "scramming."  Even with the control rods in the core, heat continued to rise because decaying radioactive materials left from the fission process continued to heat the water. The accidentaland radiation release, caused
3 mile island1
3 Mile Island
  • video

3 mile island2

Safety: 3 Mile Island

3 Mile Island

risks due to radioactivity energy released from nuclear reactions
Risks due to radioactivity : (energy released from nuclear reactions)

Metric units of energy is the Joules

Unit of radiation are rads (radiation absorbing dose)

Rads + the type of subatomic particle colliding with the body = rems (roentgen equivalent for man)

1 rem =# rads X constant value based on the particle

risks due to radioactivity
Risks due to radioactivity :

1. Affects somatic cells (body cell structure)

    • burns

2. Genetic level (mutations)

Risks depend on:

  • Length of Exposure time
  • Tissues exposed The type of particle
  • The overall energy of the radiation
  • Chemical properties of the radioactive element
risks due to radioactivity1
Risks due to radioactivity :

Dose (mrem) Cause Effect

exposure to radiation millisievert msv
Exposure to radiationmillisievert (mSv)

Various terms are used with this unit:

  • The millisievert (mSv) is commonly used to measure the effective dose in diagnostic medical procedures.
  • Dose equivalent
    • Ambient dose equivalent
    • Directional dose equivalent
    • Personal dose equivalent
    • Organ equivalent dose
  • The natural background effective dose varies considerably from place to place, but typically is around 2.4 mSv/year
link between nuclear energy and nuclear weapons
Link between Nuclear Energy and Nuclear Weapons
  • It is possible to reprocess spent fuel from conventional fission reactors to make plutonium for breeder reactors or nuclear weapons.
  • Concerns : Iran and North Korea
  • Several kilograms are needed to make a plan equal to Nagasaki and Hiroshima.
  • plutonium-239
  • Uranium -235
nuclear energy disposal
Nuclear Energy disposal
  • Radioactive waste and plutonium vitrified into glass rods
  • Plutonium converted into a mixed oxide (MOX) and burned in 2007
radioactive wastes sites
Radioactive Wastes Sites
  • Low-level radioactive wastes
  • High-level radioactive wastes
storage casks for spent fuel
Storage casks for spent fuel.
  • Holds 40 spent fuel assemblies (17.6 tons)
  • Each cast is designed to last 40 years
1982 nuclear waste policy act
1982 Nuclear Waste Policy Act
  • From Carlsbad New Mexico to Yucca Neveda
  • 2002 Congress approved the repository
  • Can house 70,000 tons of high-level radioactive wastes
  • Will hold:
    • 42,000 plus tons of spent fuel
    • Futures up to 2025
yucca mountain
Yucca Mountain
  • 145 km (90) miles from Las Vegas
  • Scientific community agrees that underground repositories are the best long term option of high-level radioactive waste.
  • Around the world there are 2 dozen countries planning similar repositories
yucca mountain1
Yucca Mountain
  • Canisters of waste, sealed in special casks, are shipped to the site by truck or train.
  • Shipping casks are removed, and the inner tube with the waste is placed in a steel, multilayered storage container.
  • An automated system sends storage containers underground to the tunnels.
  • Containers are stored along the tunnels, on their side.
nuclear power plants can be decommissioned using three methods
Nuclear power plants can be decommissioned using three methods:
  • Dismantling -- Parts of the reactor are removed or decontaminated soon after the plant closes and the land can be used.
  • Safe Storage -- The nuclear plant is monitored and radiation is allowed to decay; afterward, it is taken down.
  • Entombment -- Radioactive components are sealed off with concrete and steel, allowing radiation to “decay” until the land can be used for other purposes.
nimby principle
NIMBY Principle
  • Whenever a community is faced with the prospect of a hazardous waste facility being located in its midst, the response is usually, "Not in my back yard!"


Possible Fusion reaction


Possible Fusion reaction

Fusion reactions are difficult to maintain for extended periods of time.