this powerpoint presentation gives you all the details on Nuclear Energy

6. • Nuclear Fission =
• Nuclear Fusion =

7. Nuclear Fission

8. Nuclear Fusion

9. Nuclear Change
Nuclear Fission
• Bombs & power plants
• Big, unstable isotopes are
struck by neutrons, which
splits the isotope’s nuclei
Nuclear Fusion
• Sun and stars, some
weapons
• 2 small (light) isotopes are
forced together
– H + H = He
• More neutrons ―shoot out‖
to strike nearby isotopes,
causing a chain reaction.
• Need temps >
100,000,000ºC
• Releases more E than
fission

10. When people think about
nuclear power they think
about…
1. Effects of radiation
2. Nuclear disasters
3. Nuclear waste disposal

11. What is Radiation?
• Radiation = particles given off by
unstable atoms.
• 3 Types:
– Alpha (α)
• Travels few inches
• Blocked by paper (skin)
– Beta (β)
• Travels few feet
• Blocked by aluminum, glass
– Gamma (γ)
• Travels far
• Blocked by lead (steel & concrete).

12. www.geology.fau.edu/course_info/fall02/
EVR3019/Nuclear_Waste.ppt

13. Background Radiation
• The amount of
radiation we are
exposed to daily
from the
environment
• Average =
360 millirem/year

14. Effects of Radiation
• Genetic damages: from mutations
that alter genes
• defects can become apparent in the
next generation
• Somatic damages: to tissue, such
as burns, miscarriages & cancers
www.bio.miami.edu/beck/esc101/Chapter14&15.pp
t

16. History - Continued
People began to see the potential for using nuclear
energy for peaceful purposes. The world’s first electricity
generating reactor was constructed in the US in 1951.
In December 1953, President Dwight D. Eisenhower, in
his ―Atoms for Peace‖ speech said,
―Nuclear reactors will produce electricity so cheaply that
it will not be necessary to meter it. The user will pay an
annual fee and use as much electricity as they want.
Atoms will provide a safe, clean, and dependable source
of electricity.‖
The Russians built their first plant in 1954.

17. Half-Life
= time needed for one-half of the nuclei in a
radioisotope to decay and emit their radiation
to form a stable isotope
Uranium 235
Plutonium 239
Half-time
710 million yrs
24.000 yrs
emitted
alpha, gamma
alpha, gamma
www.bio.miami.edu/beck/esc101/Chapter14&15.pp
t

18. Renewable or NonRenewable?

19. Power plants use heat to produce electricity.
Nuclear energy produces electricity from heat
through a process called fission. Nuclear
power plants use the heat produced by fission
of certain atoms.
Nuclear fission
nucleus of atom is split into parts,
produces free neutrons and
energy

20. 92
U
Uranium
2. Uranium-235
Fission of U-235 splits nucleus
in two pieces
The fuel used in
nuclear power
plants is an
isotope of the
radioactive
element uranium
releases neutrons for chain
reaction
Nuclear fission chain
reaction  releases energy in
the form of heat.

21. A slow moving neutron
induces fission in Uranium 235

22. Uranium Mining
•
Uranium is usually mined similarly
to other heavy metals—under ground
or in open pits—but other methods
can also be used. After the uranium
is mined it is milled near the
excavation site using leaching
processes. The mining process
explained here is a combination of
two of major mines in Australia.

23. Mining risk
•
“…uranium mining, a polluting activity
that devastates large areas. Uranium ore
sometimes contains as little as 500 grams
recoverable uranium per 1000 kilograms of
earth. So, enormous amounts of rock have to
be dug up, crushed and chemically
processed to extract the uranium. The
remaining wastes, which still contain large
amounts of radioactivity, remain at the mines.
These "tailings" are often stored in a very
poor condition, resulting in the contamination
of surface- and groundwater.‖

24. Mining
•
Uranium ore is usually
located aerially; core
samples are then drilled
and analyzed by
geologists. The uranium
ore is extracted by means of drilling and blasting.
Mines can be in either open pits or underground.
Uranium concentrations are a small percentage
of the rock that is mined, so tons of tailings
waste are generated by the mining process.

25. Milling & Leaching
•The ore is first crushed into smaller bits,
then it is sent through a ball mill where it
is crushed into a fine powder. The fine
ore is mixed with water, thickened, and
then put into leaching tanks where 90%
of the uranium ore is leached out with
sulfuric acid. Next the uranium ore is
separated from the depleted ore in a
multistage washing system. The
depleted ore is then neutralized with
lime and put into a tailings repository.

26. Yellowcake
•Meanwhile, the uranium
solution is filtered, and then
goes through a solvent
extraction process that includes
kerosene and ammonia to
purify the uranium solution.
After purification the uranium is
put into precipitation tanks—the
result is a product commonly
called yellowcake.

27. Transportation
•In the final processes the
yellow cake is heated to
800˚Celcius which makes a
dark green powder which is
98% U3O8. The dark green
powder is put into 200 liter
drums and loaded into
shipping containers and are
shipped overseas to fuel
nuclear power plants.

28. Mining Leaders
• Australia and Canada are currently the
biggest Uranium miners. The processes
mentioned before that takes place in Australia
is exported because Australia does not have
a nuclear energy program.
• The mining in Australian is primarily open pit,
while the mining in Canada is mostly
underground.
• One is the major uranium producing countries,
the other is of the major corporations that
actually do the mining.

29. Production in 2000
Canada
10,682
Australia
7,578
Niger
2,895
Cameco
7218
Namibia
2,714
Cogema
6643
Uzbekistan
2,350
WMC
3693
Russia (est)
2,000
ERA
3564
Kazakhstan
1,752
Navoi
2400
USA
1,456
Rossing
2239
KazAtomProm
2018
Priargunsky
2000
South Africa
878
China (est)
500
Ukraine (est)
500
India (est)
200
France
319
others
422
tonnes U
500
Czech Republic
company
Total world
34,746
One is the major uranium
producing countries, the other
is of the major corporations
that actually do the mining.

30. World Nuclear Power Plants

31. Uranium miners today
•
“Uranium threatens the health of mine workers and
the communities surrounding the mines. According to the
International Physicians for the Prevention of Nuclear War,
uranium mining has been responsible for the largest
collective exposure of workers to radiation. One estimate
puts the number of workers who have died of lungs
cancer and silicosis due to mining and milling alone at
20,000. Mine workers are principally exposed to ionizing
radiation from radioactive uranium and the accompanying
radium and radon gases emitted from the ore. Ionizing
radiation is the part of the electromagnetic spectrum that
extends from ultraviolet radiation to cosmic rays. This type
of radiation releases high energy particles that damage
cells and DNA structure, producing mutations, impairing
the immune system and causing cancers.‖

32. 3. Nuclear Reactor  device built
to sustain a controlled nuclear
fission chain reaction
Main Components of Nuclear
Reactor:
- reactor vessel
- tubes of uranium
- control rods
- containment structure
control rods control
radioactivity, absorbs
neutrons
Containment structure
contains the reaction
in at least 3 feet of
concrete!

33. How a Nuclear Reactor
works
•
•
•
•
•
•
•
235U
fissions by absorbing a neutron and producing 2 to 3
neutrons, which initiate on average one more fission to make a
controlled chain reaction
Normal water is used as a moderator to slow the neutrons since
slow neutrons take longer to pass by a U nucleus and have
more time to be absorbed
The protons in the hydrogen in the water have the same mass
as the neutron and stop them by a billiard ball effect
The extra neutrons are taken up by protons to form deuterons
235U is enriched from its 0.7% in nature to about 3% to produce
the reaction, and is contained in rods in the water
Boron control rods are inserted to absorb neutrons when it is
time to shut down the reactor
The hot water is boiled or sent through a heat exchanger to
produce steam. The steam then powers turbines.

34. Inside a Nuclear
Reactor
• Steam outlet

• Fuel Rods

• Control Rods


35. Nuclear Reactors
•
There are usually several
hundred fuel assemblies in a
reactor core. There are
several types of reactors, but
they all use a controlled
fission process with a
moderator like water or
graphite.
•
•Pictured above is the Diablo Canyon reactor in California.

37. 235
92
U
1
0
n
92
36
Kr
141
56
Ba 301 n +201Mev
Chain reaction
In the case of 235U, however, fission is induced
when the nucleus absorbs a neutron. Not only does
the nucleus then split into two lighter nuclei, but two
or three neutrons are also released. These newly
produced neutrons can then collide with other 235U
nuclei, inducing them to fission. There can be a
nuclear chain reaction, in which the number of
fission events rapidly increase.

38. Chain reaction showing

39. chain reaction

42. Fission occurs
in the reactor
vessel. Heat is
produced.
The steam is
cooled in the
condenser to
return to the
liquid phase.
Nuclear power plant
consists of all the
parts needed to create
electricity by using
The heat is used nuclear energy
to heat water to
create steam
The steam is
used to turn the
turbine in the
generator to
produce
electricity

43. 反应堆
Cadmium rods
concrete
Water
pipe
cooling
Heat exchanging
Fuel rods
graphite
moderator
fast neutron → slow neutron

45. Three Mile Island
•
Three Mile Island is a pair
of PRW’s. The second one
was built in a hurry for tax
purposes (started operation
on December 30, 1978 to
meet deadline). On March
28, 1979, the Pilot
Operated Relief Valve was stuck
open and caused pressure to be released from the primary
cooling system. The fuel rods came apart and radioactive
material discharged into the sky. Two days later 3,500
pregnant women and children were evacuated. Although
there were no official instructions to do so, many others left
as well. Numerous residents in the aftermath developed
various cancers and thyroid diseases.

46. •
Chernobyl
Chernobyl had the RBMK
design. In an experiment,
technicians let the power of
reactor 4 fall, and on April 26,
1986 the result was rapid power
levels rising inside the core—
melting fuel and causing a
reactor
containment breach—in
addition to an internal hydrogen explosion. The
top of the reactor blew off and spewed
radioactive material into the atmosphere for 10
days.

47. Health Impacts
•
Thirty people died in direct relation to the
accident. They were the workers in the plant and
the people who assisted in the cleanup.
Approximately 2,500 additional deaths were
related to the accident. Since the accident rates of
Thyroid cancer has risen significantly. The rate of
thyroid cancer in children 15 years and younger
increase from 4 to 6 per million to 45 per million in
the Ukraine region between 1986 to 1997
(compared to 1981 to 1985). 64% of these cases
were in the most contaminated regions.

48. Environmental Impacts
•
Radioactive fall out spread throughout
the Ukraine and Europe, and eventually
the whole northern hemisphere. In the
local ecosystem (10 km radius) coniferous
trees and small mammals died. The
natural environment is recovering but there
may be long-term genetic effects.

49. Weapons
•Nuclear weapons fall under two
categories—fission weapons and fusion
weapons. Fission is splitting the nucleus of
an atom into two or more elements, which
causes a huge amount of energy to be
released. In addition if there is left over
neutrons they will cause fission in other
elements—sustaining a chain reaction.
Fusion is almost the reverse because it
requires the putting together of two nuclei.
The Hydrogen bomb is a fusion weapon,
while weapons that use U235 and Pu239 are
fission weapons. A thermonuclear weapon
detonates in three steps: fission chain
reaction, fusion reaction, and then fission
again. When a thermonuclear weapon
explodes, there is an explosion of neutrons
and gamma rays that causes a silent flash of
heat and light, followed by the extreme
pressure of a mushroom cloud that raises
millions of tons of earth resulting in nuclear
fallout.
Atomic bomb

50. Hiroshima & Nagasaki
•
The Hiroshima bomb was
nicknamed
―little boy‖ (on the left)
and was
detonated on August 6,
1945 killing
approximately 140,000 by
the end of
that year—and an
estimated total of 200,000 altogether. ―Fat Man‖ (on
the right) was dropped three days later on Nagasaki
killing approximately 70,000 people. Entire families
were wiped out. The effects of the radiation caused
birth defects in some of the survivors’ children, while
others could no longer have babies. The physical,
psychological, and environmental impacts of these
atrocities can hardly be put into words.

51. Hiroshima—before

52. Hiroshima—after

53. Hiroshima—after
•
This picture was taken by a US army medic
named Henry Dittner in October 1945.

54. Weapons Testing
•
Since 1945 there
has been 2,050
nuclear weapons tests
world wide.* This
picture is of ―Dog Shot‖
in the Nevada desert
in 1951. The second
series of tests, the first
series with large scale
troops present (with
6500 soliders). **

55. Nuclear Waste
•
There four different kinds of waste: Highlevel (spent fuel and plutonium waste),
transuranic (contaminated tools and clothes),
low and mixed low-level (hazardous waste
from hospitals), and uranium mill tailings. In
the US there is approximately 91 million
gallons of high-level waste, 11.3 million
cubic feet of transuranic waste, 472 million
cubic feet of low and mixed low level waste,
and 265 million tons of uranium tailings.

56. Moab, Utah
•
This is a picture
of a ten-million
ton pile of
uranium tailings.
The pile is right
next to the
Colorado River,
and leaks
ammonia into it
threatening the
fish. The owners of the
pile when bankrupt, so no the citizens of Moab are waiting
for the Department of Energy to clean it up. The clean up
will cost an estimated 64 million dollars.

57. Yucca Mountain
•Yucca Mountain located in
southern Nevada. Although
this location has not been
built yet, the plan is to have
the waste buried deep in the
mountain. Waste would be
transported from all over the
country in specially design
railroad cars and truck
trailers. The waste would
then be repackaged for final
burial. This plan is highly
controversial.

58. Coal-fired electric plants Nuclear plants
(one 1000 MW plant)
(one 1000 MW plant)
• releases 4.5 million tons of • produces 70 ft3 of
CO2
HLW/year
• produces 3.5 million ft3 of
waste ash/year
• no CO2 released
• releases 300 tons of SO2
and ~100 tons NOx/day
• no acidic oxides of sulfur
and nitrogen released
• releases Uranium and
Thorium from coal

59. Reactor Hazards
•
Reactor pose a serious threat radiation threat—
especially to the employees and surrounding communities.
Recently the New York times featured an article
―Extraordinary Reactor Leak Get’s the Industries Attention.‖
The implication is that if this reactor can leak, so can others.
Typically, the reactors develop boric acid under their lids—
which eats away at the steel encasement (fixable), but this
leak is in at the bottom of a reactor.* In an article featured
on CorpWatch, ―Bechtel’s Nuclear Nightmares‖ talks about a
reactor that the Bechtel corporation built in San Onofre—
that’s been shut down since 1992 for lack of safety upgrades.
The problem is that there is no place to permanently send
the reactor to and is a risk because it was built on a fault
line.** Three Mile Island and Chernobyl are two of the worst
incidences of reactor breaches.

60. Conclusion
•
•
Overall, nuclear energy disproportionately
effects rural communities and the communities
near nuclear facilities. Uranium mining and
bombing are particularly detrimental to the
environment. Further, the effects of radiation
(cancer, illness, and death) are significant. If you
find yourself in a situation where you are being
exposed to radiation, shield yourself from the
blast, and then move as far away from the
detonation area as possible (otherwise remain
indoors).