The Fukushima Daiichi nuclear disaster was a series of equipment failures, nuclear meltdowns, and releases of radioactive materials at the Fukushima I Nuclear Power Plant, following the Tōhoku earthquake and tsunami on 11 March 2011

1. Nuclear Power Station

4. Top 10 Nuclear Generating Countries

5. WPUI – Advances in Nuclear 2008
Wind
0.79
PV
0.12
Solar
Thermal
0.08
Hydro
0.07-0.37
Environmental Impacts: Area Requirements
(km2 / MW; Source - J. Davidson, 2006)
Nuclear
0.001/0.01
Biomass
5.2
Geothermal
0.003
Coal
0.01/0.04
1000 MW POWER
PLANT RUNNING @
100 % CAPACITY
(8766 GWh/YEAR)

6. WPUI – Advances in Nuclear 2008
1000 Mw-yr Power Plant Emissions
COAL GAS NUCLEAR
Sulfur-oxide ~ 1000 mt
Nitrous-oxide ~ 5000 mt 400 mt
Particulates ~ 1400 mt
Ash (solids) ~ 1million mt
CO2 > 7million mt 3.5mill. mt
Trace elements ~ 1mt** ~ 1 kg
** Volatilized heavy metals: e.g., Mercury, Lead, Cadmium, Arsenic
Spent Fuel 20-30 mt
Fission Products ~1 mt
EIA - 2004

7. Nuclear Power Economics
Estimated cost of electricity (COE) for a
new U.S. nuclear reactor:
Expense
COE
($/MWh)
Construction 50
Non-fuel operations and
maintenance (O&M)
15
Fuel-related expenses 5
Total 70

8. Nuclear v. Alternatives ($/MWh)
nuclear coal gas wind solar
capital 50 30 12 60 250
O&M 15 5 3 10 5
fuel 5 10 25-50 0 0
total 70 45 40-65 70 250
+ $100/tC 0 25 12 0 0
new total 70 70 52-77 70 250

9. Advantages
 Nuclear power generation does emit relatively low amounts of
carbon dioxide (CO2). The emissions of green house gases and
therefore the contribution of nuclear power plants to global
warming is therefore relatively little.
 This technology is readily available, it does not have to be
developed first.
 It is possible to generate a high amount of electrical energy in
one single plant

10. Economical Advantage
• The energy in one pound of highly enriched Uranium is
comparable to that of one million gallons of gasoline.
• One million times as much energy in one pound of Uranium as
in one pound of coal.
• Nuclear energy annually prevents 5.1 million tons of sulfur 2.4
million tons of nitrogen oxide 164 metric tons of carbon

11. Disadvantages
 The problem of radioactive waste is still an unsolved one.
 High risks: It is technically impossible to build a plant with
100% security.
 The energy source for nuclear energy is Uranium. Uranium
is a scarce resource, its supply is estimated to last only for
the next 30 to 60 years depending on the actual demand.
 Nuclear power plants as well as nuclear waste could be
preferred targets for terrorist attacks..

12. Chernobyl Disaster
• The Chernobyl disaster was a catastrophic nuclear
accident that occurred on 26 April 1986 at the Chernobyl
Nuclear Power Plant in Ukraine (then officially Ukrainian
SSR)
• An explosion and fire released large quantities of radioactive
contamination into the atmosphere, which spread over much of
Western USSR and Europe.
• The Chernobyl disaster is widely considered to have been the
worst nuclear power plant accident in history, and is one of
only two classified as a level 7 event on the International
Nuclear Event Scale (the other being the Fukushima Daiichi
nuclear disaster in 2011).
• The battle to contain the contamination and avert a greater
catastrophe ultimately involved over 500,000 workers and cost
an estimated 18 billion rubles [1 US dollar = 31.1130 Russian
rubles].

13. Chernobyl Disaster
Aftermath: very extensive
damage to the main
reactor hall (image center)
and turbine building
(image lower left)

14. The abandoned
city
of Pripyat with
Chernobyl plant
in the distance

15. Fukushima Daiichi nuclear disaster
• The Fukushima Daiichi nuclear disaster was a series
of equipment failures, nuclear meltdowns, and releases of
radioactive materials at the Fukushima I Nuclear Power
Plant, following the Tōhoku earthquake and tsunami on
11 March 2011.
• It is the largest nuclear disaster since the Chernobyl
disaster of 1986.
• The radiation released was an order of magnitude lower
than that released from Chernobyl, and some 80% of the
radioactivity from Fukushima was deposited over the
Pacific Ocean; preventive actions taken by the Japanese
government may have substantially reduced the health
impact of the radiation release.

16. Radiation and You

17. Nuclear Fuel

22. Nuclear Fission
 A nuclear reaction in which a massive nucleus
splits into smaller nuclei with the simultaneous
release of energy.

23. Nuclear Chain Reactions
 Nuclear fission releases more neutrons which trigger more fission
reactions
 The number of neutrons released determines the success of a chain
reaction

24. How the Chain Reaction is Controlled
 In a nuclear fission reaction in a nuclear
power plant, the radioactive element
Uranium is used in a chain reaction.
 The fission splits off two neutrons, which
in turn strike two atoms.
 Two neutrons are split from each of the two
atoms. Each of these neutrons then go on to
strike another atom. Each of those atoms
are split releasing two neutrons, which go
on and hit more Uranium atoms.
 The chain reaction continues on and on,
getting bigger and bigger with each split.
 The things that slow down a chain reaction
are the control rods, which absorb
neutrons.

25. When/where is control used?
• Nuclear power plants work by controlling the rate of the
nuclear reactions, and that control is maintained through
several safety measures. The materials in a nuclear reactor core
and the uranium enrichment level make a nuclear explosion
impossible, even if all safety measures failed.
• On the other hand, nuclear weapons are engineered to produce
a reaction that is so fast and intense it cannot be controlled
after it has started. When properly designed, this uncontrolled
reaction can lead to an explosive energy release.

26. Man Made Fuels

29. Nuclear Reactor

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

32. Reactor Core

33. Moderator

34. Nuclear Fission from Slow Neutrons and Water
Moderator

36. Thermal Shielding

37. Reflector

38. Reactor Vessel or Reactor Tank

40. Coolant Flow

41. Control Rods

42. Biological Shield

43. Reactor Operation
• 1 ton of natural or slightly enriched Uranium can produce 240,000,000
kWhr energy.
• When 1 lb U-235 fissions, 0.00091 lb of its mass only converts to energy,
which is only 1.2 percent of the total fissionable and fertile material.

45. Types of Reactor
There are two most commonly used reactors:
1.Pressurized Water Reactor
2.Boiling Water Reactor

46. Pressurized Water Reactor
• This is the most common type of commercial reactor and was originally
developed in the USA for submarine propulsion.
• Nearly 60% of the world's commercial reactors are PWRs
• The fuel is uranium dioxide enriched to about 4%, contained in
zirconium alloy tubes.
• Pressurized water acts as both moderator and coolant and heats water in
a secondary circuit via a steam generator to produce steam.
• The reactor is encased in a concrete biological shield within a
secondary containment.
• The design is very compact because water is a more effective
moderator than graphite.
• A PWR’s thermal efficiency is about 32%.
• PWRs keep water under pressure so that it is heated, but does not boil.
Water from the reactor and the water in the steam generator that is turned
into steam never mix. In this way, most of the radioactivity stays in the
reactor area.

47. Pressurized Water Reactor
In a typical commercial pressurized light-water
reactor(1) the core inside the reactor vessel creates
heat, (2) pressurized water in the primary coolant
loop carries the heat to the steam generator, (3)
inside the steam generator steam is generated, and
(4) the steam line directs the steam to the main
turbine, causing it to turn the turbine generator,
which produces electricity. The unused steam is
exhausted in to the condenser where it condensed
into water. The resulting water is pumped out of the
condenser with a series of pumps, reheated and
pumped back to the steam generators. The reactor's
core contains fuel assemblies that are cooled by
water circulated using electrically powered pumps.
These pumps and other operating systems in the
plant receive their power from the electrical grid. If
offsite power is lost emergency cooling water is
supplied by other pumps, which can be powered by
onsite diesel generators. Other safety systems, such
as the containment cooling system, also need power.
Pressurized-water reactors contain between 150-200
fuel assemblies

48. Pressurized Water Reactor

49. Boiling Water Reactor
• A BWR is effectively a PWR without the steam generator.
• Water is pumped through the core, again acting as both moderator
and coolant, inside a pressure vessel.
• About 10% of the water is converted to steam and passed to steam
turbines.
• The fuel is similar to that of a PWR, but the power density (power
produced per unit volume of core) is about half, with lower
pressures and temperatures.
• The cost advantage of not having steam generators is offset by the
disadvantages of a single cooling system, which can potentially
cause contamination throughout the steam plant if fuel can failures
occur.
• A BWR’s thermal efficiency is again about 32%

50. Boiling Water Reactor
In a typical commercial boiling-water reactor, (1) the
core inside the reactor vessel creates heat, (2) a steam-
water mixture is produced when very pure water
(reactor coolant) moves upward through the core,
absorbing heat, (3) the steam-water mixture leaves the
top of the core and enters the two stages of moisture
separation where water droplets are removed before the
steam is allowed to enter the steam line, and (4) the
steam line directs the steam to the main turbine, causing
it to turn the turbine generator, which produces
electricity. The unused steam is exhausted into the
condenser where it is condensed into water. The
resulting water is pumped out of the condenser with a
series of pumps, reheated and pumped back to the
reactor vessel. The reactor's core contains fuel
assemblies that are cooled by water circulated using
electrically powered pumps. These pumps and other
operating systems in the plant receive their power from
the electrical grid. If offsite power is lost emergency
cooling water is supplied by other pumps, which can be
powered by onsite diesel generators. Other safety
systems, such as the containment cooling system, also
need electric power. Boiling-water reactors contain
between 370-800 fuel assemblies

51. Boiling Water Reactor