nuclear energy

Slide 1:

Nuclear energy ANGELYN T. VIDAD BSE-IIIC

NUCLEAR ENERGY:

NUCLEAR ENERGY The energy created in a nuclear reaction (changes in the structure of the nuclei of atoms). The nucleus of an atom is the source of nuclear energy.

  Nuclear energy can be produced: :

NATURALLY Example: the Sun and the other stars make heat and light by nuclear reactions MAN-MADE Example: Machines called nuclear reactors, parts of nuclear power plants, provide electricity for many cities. Nuclear energy can be produced:

Nuclear energy is produced in two different ways::

NUCLEAR FISSION - the nuclei of atoms are split - examples are atomic bombs and nuclear reactors NUCLEAR FUSION - the nuclei of atoms are joined together or fused - examples are the Sun and stars and the hydrogen bomb Nuclear energy is produced in two different ways:

FACTS ABOUT NUCLEAR POWER :

FACTS ABOUT NUCLEAR POWER Nuclear power is generated using Uranium. Nuclear power produces around 17% of the world’s energy needs. Some military ships and submarines have nuclear power plants for engines. There is more than 430 nuclear power plants generating electricity worldwide ( 100 in the US, 20 in West Germany, 49 in France and Japan with more than 30 operational reactors and many other countries).

NUCLEAR ENERGY:

NUCLEAR ENERGY Nuclear energy is the most concentrated form of energy. Second greatest source of energy in the world. Most of us live within 10 miles of the Surry Nuclear Power Plant which converts nuclear energy into electromagnetic energy.

History of Nuclear Power:

History of Nuclear Power 1938 – Scientists study Uranium nucleus 1941 – Manhattan Project begins 1942 – Controlled nuclear chain reaction December 2, 1942- World’s First Nuclear Fission Reaction 1945 – U.S. uses two atomic bombs on Japan 1949 – Soviets develop atomic bomb 1952 – U.S. tests hydrogen bomb 1955 – First U.S. nuclear submarine 1956 - The First Large- scale Nuclear Power Station opened at Calder Hall in Cumbria, England November 15, 1957- First Licensed Atomic Power Plant was operated in Vallecitos , California

KEY PARTS OF A LIGHT-WATER REACTOR (LWRs):

KEY PARTS OF A LIGHT-WATER REACTOR (LWRs) CORE. This typically contains 35, 000- 40, 000 long, thin fuel rods bundled in 180 fuel assemblies of around 200 rods each. CONTROL RODS. These are made of materials such as cadmium or boron that absorb neutrons. They are moved in and out of the reactor core to regulate that rate of fission and thus the amount of power the reactor produces.

KEY PARTS OF A LIGHT-WATER REACTOR (LWRs):

MODERATOR . This is a material such as liquid water, solid graphite or heavy water, used to slow down the neutrons emitted by the fission process so that the chain reaction can be kept going. COOLANT. This material, usually water, is circulated through the reactor’s core to remove heat to keep fuel rods and other materials from melting and to produce steam from generating electricity. KEY PARTS OF A LIGHT-WATER REACTOR (LWRs)

HOW DOES A NUCLEAR FISSION REACTOR WORK?:

HOW DOES A NUCLEAR FISSION REACTOR WORK? NUCLEAR FISSION GENERATORS TURBINES STEAM Electrical Power A main bit to remember:

NUCLEAR FUEL CYCLE:

NUCLEAR FUEL CYCLE Uranium mining and milling Conversion and enrichment Fuel rod fabrication POWER REACTOR Reprocessing, or Radioactive waste disposal Low-level in commercial facilities High level at plants or underground repository

Slide 13:

economics levelling off in the demand for electricity scarce uranium deposits waste disposal problems nuclear accidents FACTORS LIMITING THE FURTHER EXPANSION OF NUCLEAR POWER PLANTS

ADVANTAGES :

ADVANTAGES Nuclear plants don’t emit air pollutants. It does not produce smoke or carbon dioxide. Produce huge amounts of energy from small amounts of fuel. Nuclear power plants could still produce electricity after coal and oil become scarce. Produces small amounts of waste. Nuclear power is reliable.

DISADVANTAGES:

DISADVANTAGES Nuclear explosions produce radiation. Meltdown of the nuclear reactor, could lead to nuclear explosion. Although not much waste is produced, it is very, very dangerous. Nuclear power is reliable, but a lot of money has to be spent on safety. Nuclear power plants have limited life expectancy.

HOW TO MAKE NUCLEAR POWER PLANTS SAFE? :

HOW TO MAKE NUCLEAR POWER PLANTS SAFE? Thick walls and concrete- and- steel shields surrounding the reactor vessel. A system for automatically inserting control rods into the core to stop fission under emergency conditions. A steel - reinforced concrete containment building to keep radioactive gases and materials from reaching the atmosphere after an accident.

HOW TO MAKE NUCLEAR POWER PLANTS SAFE?:

HOW TO MAKE NUCLEAR POWER PLANTS SAFE? Large filter systems and chemical sprayers inside the containment building to remove radioactive dust from the air and further reduce chances of radioactivity reaching the environment. Systems to condense steam released from a ruptured reactor vessel and prevent pressure from rising beyond the holding power of containment building walls.

HOW TO MAKE NUCLEAR POWER PLANTS SAFE?:

HOW TO MAKE NUCLEAR POWER PLANTS SAFE? An emergency core- cooling system to flood the core automatically with huge amounts of water within one minute to prevent meltdown of the reaction core. Two separate power lines servicing the plant, and several diesel generators to supply back up power for the huge pumps in the emergency core- cooling system. An automatic backup system to replace each major part of the safety system in the event of a failure.

WHAT CAN WE DO WITH WORN-OUT NUCLEAR POWER PLANTS? :

WHAT CAN WE DO WITH WORN-OUT NUCLEAR POWER PLANTS? immediate dismantling mothballing for 30-100 years by putting up a barrier and setting up a 24-hour security system and then dismantling the plant. entombment by covering the reactor with reinforced concrete and putting up a barrier to keep out intruders for several thousand years.

WHAT CAN WE DO WITH WORN-OUT NUCLEAR POWER PLANTS?:

WHAT CAN WE DO WITH WORN-OUT NUCLEAR POWER PLANTS? Each method involves: shutting down the plant removing the spent fuel from the reactor core draining all liquids flushing all pipes sending all radioactive materials to an approved waste storage site yet to be built

WHAT DO WE DO WITH NUCLEAR WASTE? :

WHAT DO WE DO WITH NUCLEAR WASTE? Bury it deep underground. Shoot it into space or into the Sun. Bury it under the Antartic ice sheet or the Greenland ice cap. Dump it into descending subduction zones in the deep ocean Change it into harmless or less harmful, isotopes.

Slide 22:

“ The generation of electricity from nuclear energy is only justifiable if there are solid solutions to the unsolved problems to which it gives rise.” - World Commission on Environment and Development

Slide 23:

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