Development of Nuclear Energy

Wan Ning, Debbra, Joon Khai, Ryan Teo

Beginnings of Nuclear Energy• The pursuit of nuclear energy for electricity generation began in the early 20th century.

• However, means of harnessing such energy was impractical, because intensely

radioactive elements were, by their very nature, short-lived.

• This situation, however, changed in the late 1930s, with the discovery of nuclear fission.

• In 1932, James Chadwick discovered the neutron, which was immediately recognized as

a potential tool for nuclear experimentation because of its lack of an electric charge.

• Experimentation with bombardment of materials with neutrons led Frédéric and Irène

Joliot-Curie to discover induced radioactivity in 1934, which allowed the creation of

radium-like elements at much less the price of natural radium.

History• In 1938, German chemists Otto Hahn and Fritz Strassmann, along with Austrian physicist

Lise Meitner and Otto Robert Frisch, conducted experiments with the products of

neutron-bombarded uranium,.

• They determined that the relatively tiny neutron split the nucleus of the massive uranium

atoms into two roughly equal pieces.

• This was an extremely surprising result: all other forms of nuclear decay involved only

small changes to the mass of the nucleus, whereas this process—dubbed "fission" —

involved a complete rupture of the nucleus.

• Numerous scientists, recognized that if fission reactions released additional neutrons, a

self-sustaining nuclear chain reaction could result.

• Once this was experimentally confirmed and announced by Frédéric Joliot-Curie in 1939,

scientists in many countries (including the United States, the United Kingdom, France,

Germany, and the Soviet Union) petitioned their governments for support of nuclear

fission research, for the development of a nuclear weapon.

World War 2

In the United States, that led to the creation of the first man-made reactor,

known as Chicago Pile-1, which achieved criticality on December 2, 1942.

This work became part of the Manhattan Project, which made enriched

uranium and built large reactors to breed plutonium for use in the first

nuclear weapons, which were used on the cities of Hiroshima and Nagasaki

during World War II.

• The atomic bombings of the cities of Hiroshima and Nagasaki in Japan

were conducted by the United States during the final stages of World War

II in 1945. The two events are the only use of nuclear weapons in war to

date.

• American airmen dropped Little Boy on the city of Hiroshima on 6 August

1945, followed by Fat Man over Nagasaki on 9 August.

Nagasaki and Hiroshima

• Within the first two to four months of the bombings, the acute effects killed

90,000–166,000 people in Hiroshima and 60,000–80,000 in Nagasaki, with

roughly half of the deaths in each city occurring on the first day.

• The Hiroshima health department estimated that, of the people who died

on the day of the explosion, 60% died from flash or flame burns, 30% from

falling debris and 10% from other causes.

• During the following months, large numbers died from the effect of burns,

radiation sickness, and other injuries, compounded by illness.

After WWII

After World War II, the prospects of using Nuclear Energy for good, rather than

simply for war, was advocated as a reason not to keep all nuclear research

controlled by military organizations. However, most scientists agreed that

civilian nuclear power would take at least a decade to master, and the fact

that nuclear reactors also produced weapons-usable plutonium created a

situation in which most national governments (such as those in the United

States, the United Kingdom, Canada, and the USSR) attempted to keep

reactor research under strict government control and classification.

Processes of Production• Nuclear Energy is formed through nuclear fission, which is the process of nuclear particles

being split up

• The neutron is and was very important in all forms of nuclear fission. The neutron, in nuclear fission, is absorbed into a nuclear particle, which in nuclear power plants is known as U235.

• The process works when the U235 is excited by the neutron, and becomes an uranium-236

Nuclear ReactorsNuclear Reactors are also very important in the production of nuclear energy. The reactor core generates heat in a

number of ways:

• The kinetic energy of fission products is converted to thermal energy when these nuclei collide

with nearby atoms.

• The reactor absorbs some of the gamma rays produced during fission and converts their energy

converted into heat.

• Heat is produced by the radioactive decay of fission products and materials that have been activated by neutron absorption. This decay heat-source will remain for some time even after the reactor is shut down.

Harmful Effects and Negative Impact of Nuclear EnergyWaste and Greenhouse Gases

• Most of the stages of the nuclear fuel chain use up fossil fuels and give out carbon dioxide

• These processes are mining, milling, transport of nuclear energy, fuel fabrication, enrichment of nuclear energy, reactor construction, decommissioning of the power plant and waste management

• All of these processes will result in an increase in the greenhouse gases in the atmosphere.

• The buildup of greenhouse gases absorbs the infrared rays from the Earth, causing the global temperature of the Earth and giving rise to global warming

• Around 20–30 tons of waste is produced per year in each nuclear reactor. The world's nuclear plants creates about 10,000 metric tons of

nuclear fuel each year

Harmful Effects and Negative Impact of Nuclear EnergyFukushima Accident

• Technicians of the nuclear plant tried to pump in seawater to keep the uranium fuel rods cool

• They released radioactive gas from the reactors in order to make room for the seawater

• Pollutes the seawater that would be eventually released with uranium

• Harmful and poisonous to the organisms living in the water

• Causes the surrounding (within a 20 to 30 km range) land to be barren and cannot be planted with any crops or vegetation

• Can affect people as the radiation emitted from the plant could cause radiation sickness (poisoning, toxicity)

Harmful Effects and Negative Impact of Nuclear EnergyChernobyl Accident

• The disaster began during a systems test on Saturday, 26 April 1986 at reactor number four of the Chernobyl plant, which is near the city of Pripyat.

• There was a sudden and unexpected power surge, and when an emergency shutdown was attempted, an exponentially larger spike in power output occurred, which led to a reactor vessel rupture and a series of steam explosions. These events exposed the graphite moderator of the reactor to air, causing it to ignite. The resulting fire sent a plume of highly radioactive fallout into the atmosphere and over an extensive geographical area, including Pripyat. The plume drifted over large parts of the western Soviet Union and Europe. From 1986 to 2000, 350,400 people were evacuated and resettled from the most severely contaminated areas of Belarus, Russia, and Ukraine.

• Ukrainian officials estimate the area will not be safe for human life again for another 25,000 years ( Year 26, 986).

• Thousands of people have died and even more are still suffering the effects of it.

Benefits of Nuclear Energy• Nuclear power plants emit less than one hundredth the greenhouse

gases of coal or gas power stations

• Nuclear energy has the lowest harmful impacts on the environment

• Nuclear power plants do not emit harmful gases, and only require a

relatively small area

• Nuclear energy is the most "ecologically efficient" of all energy

sources

• Produces the most electricity in relation to its minimal environmental

impact

• Nuclear energy is an emission-free energy source because it does not

burn anything to produce electricity

• The nuclear energy also does not produce carbon dioxide or other

greenhouse gases which can cause global warming

Uses of Nuclear Energy· Health

– Treatments Cancer can be treated through the use of radiotherapy.

– Diagnostic and research purposesThey aid in measuring the concentration of various enzymes, some drugs,

hormones and many other substances that are present in the human blood.

– SterilizationUsed to sterilize medical supplies like cotton, bandages, gloves used for surgery,

syringes and burn dressings.

– Detection of pollutants in the airDangerous residues present even in small amounts of air can be very harmful to

humans, so detecting them ensures our health and safety.

Uses of Nuclear Energy

· Food and agricultureMany organisations have been using nuclear energy to increase agricultural production, one major advancement is the Sterile Insect Technique (SIT).Nuclear energy can help:

– Improve food availability and quality – Reduce production costs – Minimize pollution of food crops

· Generating electricityThe energy released by the fission that takes place in a nuclear reactor of the nuclear power plant is converted and generated into electricity.

· Power sourcesNuclear fission emits lots of energy which is used for:

– Heart pacemakers (used to regulate beating of the heart) – Beacons and satellites – Missions in space

The pursuit of nuclear energy for electricity generation began soon after the discovery in the early 20th century that radioactive elements, such as radium, released immense amounts of energy, according to the principle of mass–energy equivalence. After World War 2, nuclear energy was used for good, rather than simply for war.

In order to develop nuclear energy, man have to use uranium and extract the energy from it through reactors. In the process of this extraction, however, nuclear waste is produced, which is bio hazardous and acts as a pollutant, that may leak into water sources, poisoning it. Since nuclear waste is unable to be filtered from water, the water sources are rendered unusable.

Not only that, it takes huge factories to house the enormous reactors needed to produce nuclear energy. This takes much resources to build, and man has to clear large pockets of land first. This is environmentally damaging, as it contributes to deforestation. Clearing land also causes the animals that lived there to lose their home which may also cause the extinction of many species of animals.

Thus, the production of nuclear energy is harmful to the environment.

Give a description of this development in less than 200 words. In your description, explain how man has altered the living and nonliving factors in the ecosystem to bring about this development.