Nuclear Energy

Prof. ParkUTI-111

Essex County College

Nuclear Energy Around the World

• As of September 2009, 30 countries worldwide were operating 436 nuclear reactors for electricity generation and 53 new nuclear plants were under construction in 14 countries.

• Nuclear power plants provided about 14 percent of the world's electricity production in 2008. In total, 15 countries relied on nuclear energy to supply at least one-quarter of their total electricity.

Nuclear Energy Around the World• Countries generating the largest percentage of

their electricity in 2008 from nuclear energy were:

Country Percent Country Percent France 76.2 Lithuania 72.9 Slovakia 56.4 Belgium 53.8 Ukraine 47.4 Sweden 42.0 Slovenia 41.7 Armenia 39.4 Switzerland 39.2 Hungary 37.2 S. Korea 35.6 Bulgaria 32.9

U.S. Nuclear Power Plants

• Nuclear energy provides almost 20 percent of the United States' electricity and is its No. 1 source of emission-free electricity.

• Number of operating reactors: 104 (35 boiling water reactors, 69 pressurized water reactors)

• 14 BWR plants have one reactor; nine have two reactors; one has three reactors

• 15 PWR plants have one reactor; 24 have two reactors; two have three reactors

U.S. Nuclear Power Plants• Companies licensed to operate nuclear reactors: 32• Number of states with operating reactors : 31

In six states for 2008, nuclear makes up the largest percentage of their electricity generated:

State Percent State Percent Vermont 79.7 Connecticut 51.2 South Carolina 50.9 New Jersey 50.4 New Hampshire 41.0 New York 31.0

• Largest U.S. nuclear plant: Palo Verde (Arizona): 3 reactors at 1,311 / 1,314 / 1,247 megawatts (MW) each for a total of 3,872 MW

• Smallest U.S. nuclear plant: Ft. Calhoun (Neb.): 1 reactor at 478 MW• Oldest operating nuclear plant/year: Oyster Creek in New Jersey,

operating license issued April 1969

Nuclear Power Plants in NJ

Capacity (MW) 2008

Generation (MWh) 3-year Average

Capacity Factor (%)

Hope Creek 1,061 9,992,387 95.6

Oyster Creek 619 4,664,005 88.4

Salem 1 1,174 9,327,413 93.0

Salem 2 1,130 8,210,993 90.9

Total 3,984 32,194,798 91.9

Nuclear Energy Is Energy from Atoms

• Nuclear energy is energy in the nucleus (core) of an atom. Atoms are tiny particles that make up every object in the universe. There is enormous energy in the bonds that hold atoms together.

• Nuclear energy can be used to make electricity. But first the energy must be released. It can be released from atoms in two ways: nuclear fusion and nuclear fission.

Nuclear Energy Is Energy from Atoms

• In nuclear fission, atoms are split apart to form smaller atoms, releasing energy. Nuclear power plants use this energy to produce electricity.

• In nuclear fusion, energy is released when atoms are combined or fused together to form a larger atom. This is how the sun produces energy. Fusion is the subject of ongoing research, but it is not yet clear that it will ever be a commercially viable technology for electricity generation.

Nuclear Fuel — Uranium• The fuel most widely used by nuclear plants for nuclear fission

is uranium. Uranium is nonrenewable, though it is a common metal found in rocks all over the world. Nuclear plants use a certain kind of uranium, referred to as U-235. This kind of uranium is used as fuel because its atoms are easily split apart. Though uranium is quite common, about 100 times more common than silver, U-235 is relatively rare.

• Most U.S. uranium is mined in the Western United States. Once uranium is mined, the U-235 must be extracted and processed before it can be used as a fuel.

Nuclear Fuel — Uranium

• During nuclear fission, a small particle called a neutron hits the uranium atom and splits it, releasing a great amount of energy as heat and radiation. More neutrons are also released. These neutrons go on to bombard other uranium atoms, and the process repeats itself over and over again. This is called a chain reaction.

Drawing of How Fission Splits the Uranium Atom

Milestones in the History of Nuclear Energy

• December 2, 1942: The Nuclear Age began at the University of Chicago when Enrico Fermi made a chain reaction in a pile of uranium.

• August 6, 1945: The United States dropped an atomic bomb on Hiroshima, Japan, killing over 100,000.

• August 9, 1945: The United States dropped an atomic bomb on Nagasaki, Japan, killing over 40,000.

• November 1, 1952: The first large version of the hydrogen bomb (thousands of times more powerful than the atomic bomb) was exploded by the United States for testing purposes.

• February 21, 1956: The first major nuclear power plant opened in England.

• A more in depth and detailed history of nuclear energy is on the nuclear past page.

Advantages of Nuclear Energy

• The Earth has limited supplies of coal and oil. Nuclear power plants could still produce electricity after coal and oil become scarce.

• Nuclear power plants need less fuel than ones which burn fossil fuels. One ton of uranium produces more energy than is produced by several million tons of coal or several million barrels of oil.

• Coal and oil burning plants pollute the air. Well-operated nuclear power plants do not release contaminants into the environment.

Disadvantages of Nuclear Energy • The nations of the world now have more than enough nuclear bombs to kill

every person on Earth. The two most powerful nations -- Russia and the United States -- have about 50,000 nuclear weapons between them. What if there were to be a nuclear war? What if terrorists got their hands on nuclear weapons? Or what if nuclear weapons were launched by accident?

• One possible type of reactor disaster is known as a meltdown. In such an accident, the fission reaction goes out of control, leading to a nuclear explosion and the emission of great amounts of radiation. – In 1979, the cooling system failed at the Three Mile Island nuclear

reactor near Harrisburg, Pennsylvania. Radiation leaked, forcing tens of thousands of people to flee. The problem was solved minutes before a total meltdown would have occurred. Fortunately, there were no deaths.

– In 1986, a much worse disaster struck Russia's Chernobyl nuclear power plant. In this incident, a large amount of radiation escaped from the reactor. Hundreds of thousands of people were exposed to the radiation. Several dozen died within a few days. In the years to come, thousands more may die of cancers induced by the radiation.

Disadvantages of Nuclear Energy • Nuclear explosions produce radiation. The nuclear radiation

harms the cells of the body which can make people sick or even kill them. Illness can strike people years after their exposure to nuclear radiation.

• Nuclear explosions produce radiation. The nuclear radiation harms the cells of the body which can make people sick or even kill them. Illness can strike people years after their exposure to nuclear radiation.

• Nuclear reactors also have waste disposal problems. Reactors produce nuclear waste products which emit dangerous radiation. Because they could kill people who touch them, they cannot be thrown away like ordinary garbage. Currently, many nuclear wastes are stored in special cooling pools at the nuclear reactors.

• The United States plans to move its nuclear waste to a remote underground dump by the year 2010.

• In 1957, at a dump site in Russia's Ural Mountains, several hundred miles from Moscow, buried nuclear wastes mysteriously exploded, killing dozens of people.

• Nuclear reactors only last for about forty to fifty years.

RadiationIn Reactors, Radiation Is Trapped and Contained in Several Ways:

Nuclear Fuel Cycle • Uranium mining • Uranium milling • Conversion and enrichment • Fuel fabrication • Power generation and burn-up• Used fuel • Reprocessing • Uranium and plutonium recycling • Used fuel disposal • Wastes

Material balance in the nuclear fuel cycle • The following figures may be regarded as typical for the annual

operation of a 1000 MWe nuclear power reactor:a • Mining20,000 tonnes of 1% uranium ore• Milling 230 tonnes of uranium oxide concentrate (which

contains 195 tonnes of uranium)• Conversion 288 tonnes uranium hexafluoride, UF6 (with 195 t

U)• Enrichment 35 tonnes enriched UF6 (containing 24 t enriched

U) - balance is 'tails‘• Fuel fabrication 27 tonnes UO2 (with 24 t enriched U)• Reactor operation 8640 million kWh (8.64 TWh) of electricity

at full output• Used fuel 27 tonnes containing 240 kg plutonium, 23 t

uranium (0.8% U-235), 720kg fission products, also transuranics