Sust Chap 12

Define biomass, explain why it is an example of indirect solar energy, and outline how it is used as a source of energy

Biomass consists of plant material that is used as fuel. Biomass is an example of indirect solar energy because it includes organic materials produced by photosynthesis. Biomass is burned directly to produce heat or electricity or converted to solid (charcoal), gas (biogas), or liquid (methanol and ethanol) fuels. Biomass is already being used for energy on a large scale, particularly in developing nations. India and China have several million biogas digesters that produce biogas from household and agricultural wastes.

Describe geothermal energy and tidal energy, the two forms of renewable energy that are not direct or indirect results of solar energy.

Geothermal energy is the use of energy from Earth's interior for either space heating or the generation of electricity. Geothermal energy can be obtained from hydrothermal reservoirs of heated water near Earth's surface. The established technology for extracting geothermal energy from heated area of Earth's crust involves drilling wells and bringing the steam or hot water to the surface. Tidal energy is a form of renewable energy that relies on the ebb and flow of the tides to generate electricity; it is currently used on a very limited scale

ionizing radiation

High-energy radiation capable of producing ionization in substances through which it passes

Distinguished between nuclear energy and chemical energy

In ordinary chemical reactions, the atoms of one element do not change into atoms of another element, nor does any of their mass (matter) change into energy In contrast, nuclear energy is the energy released by nuclear fission or fusion. In nuclear energy small amounts of matter from atomic nuclei are converted into large amounts of energy.

Distinguish between low-level and high-level radioactive wastes

Low-level radioactive wastes are radioactive solids, liquids, or gases that give off small amounts of ionizing radiation. High-level radioactive wastes are solids, liquids, or gases that initially give off large amounts of ionizing radiation.

Discuss the pros and cons of electric power produced by nuclear energy

Nuclear power can serve as an alternative to electricity generation from coal and natural gas, both of which contribute greenhouse gases to the atmosphere. One reason proponents of nuclear energy argue for its widespread adoption is that it has less of an environmental impact than fossil fuels, particularly coal. Nuclear energy emits few pollutants into the atmosphere and provides power without producing carbon dioxide. However, it generates highly radioactive waste such as spent fuel; every country that uses nuclear power is seeking a permanent waste-disposal site. Safety remains a concern at nuclear power plants.

Distinguish between active and passive solar heating and describe how each is used

Passive solar heating is a system of putting the sun's energy to use without requiring mechanical devices (pumps or fans) to distribute the collected heat. Currently, about 7% of new homes built in the United States have passive solar features. Active solar heating is a system of putting the suns energy to use in which a series of collectors absorb the solar energy, and pumps or fans distribute the collected heat. Active solar heating is used for heating water and, to a lesser extent, space heating.

Contrast the advantages and disadvantages of solar thermal electric generation and photovoltiacs in converting solar energy into electricity

Solar thermal electric generation is a means of producing electricity in which the sun's energy is concentrated by mirrors or lenses onto a fluid-filled pipe; the heated fluid is used to generate electricity. Solar thermal plants are not yet cost-competitive with traditional fuels, but they are more efficient than other direct solar technologies, and they do not produce air pollution or contribute to acid rain or global climate change. Photosynthesis (PV) include solar cells, wafers or thin-films of solid-state materials, such as silicon or gallium arsenide, that are treated with certain metals so that they generate electricity- that is a flow of electrons-when they absorb solar energy. PV devices generate electricity with no pollution and minimal maintenance, but most are only about 10% to 15% efficient at converting solar energy to electricity

Discuss the link between nuclear energy and nuclear weapons

The increase in global supplies of weapons-grade plutonium and plutonium wastes from commercial nuclear reactors threatens international security because it increases the chance that certain nations and terrorists groups could use them to make nuclear weapons

Describe the nuclear power plant accidents at Three Mile Island, Chernobyl, and Fukushima Daiichi

The most serious nuclear reactor accident in the United States occurred in 1979 at the Three Mile Island power plant in Pennsylvania. A partial meltdown of the reactor core took place, although the containment building kept almost all the radioactivity from escaping. In 1986 a nuclear reactor accident occurred in Chernobyl in the former Soviet Union (now Ukraine). One or two explosions ripped apart a nuclear reactor and expelled large quantities of radioactive material into the atmosphere, resulting in widespread environmental pollution as well as serious local contamination. As this book goes to press, the extent of an accident at the Fukushima Daiichi nuclear power plant in Japan remains unknown, but includes an explosion, deaths, evacuations, and extensive contamination.

Briefly describe how future nuclear power reactors will differ from current plants.

The next generation of nuclear power plants is expected to be smaller, simpler, safer, and more cost-effective than the reactors currently in use around the world. The NRC has already approved four new designs, and more are proposed. Nuclear fusion as a source of energy is many years from becoming a reality

Daniel M. Kammen

UC Berkeley professor who researched appropriate energy sources & uses and developed & promoted energy solutions

Describe the locations that can make optimum use of wind energy and of hydropower, and compare the potential of wind energy and hydropower

Wind energy is electric energy obtained from surface air currents caused by the solar warming of air. Harvesting wind energy to generate electricity has great potential because it is currently the most cost-competitive of all forms of solar energy. Harnessing wind energy is the most profitable in areas with fairly continual winds, such as islands, coastal areas, mountain passes, and grasslands. Hydropower relies on flowing or falling water to generate electricity. The damming of rivers and streams to generate electricity is the major form of hydropower. Currently, hydropower produces about 19% of the world's electricity. Environmental and social problems associate with hydropower include ecological destruction upstream and downstream, increased evaporation of water, disease and pollution, displacement of people, and inundation of farmland.

containment building

a building that contains the liquid sodium so that the coolant doesn't react releasing radioactive materials into the atmosphere

biogas

a clean fuel composed of a mixture of gases (mostly methane)

sunk cost

a cost that was spent in the past and therefore, makes no sense to factor into the current cost

nuclear reactor

a device that initiates and maintains a controlled nuclear fission chain reaction to produce energy for electricity

hydropower

a form of renewable energy that relies on flowing or falling water to generate mechanical energy or electricity

tidal energy

a form of renewable energy that relies on the ebb and flow of the tides to generate electricity

Stirling engine

a heat engine (which is a solar thermal electric generation system)

ethanol (ethyl alcohol)

a liquid fuel made from biomass

methanol (methyl alcohol)

a liquid fuel made from biomass

solar thermal electric generation

a means of producing electricity in which the sun's energy is concentrated by mirrors or lenses to either heat a fluid-filled pipe or drive a Stirling engine

photovoltaics (PV)

a method of converting sunlight to electricity using layers of materials that either readily give up or absorb electrons

solar cookers

a new technology to capture solar energy directly to cook food

mixed oxide fuel (MOF)

a reactor fuel that contains a combination of uranium oxide and plutonium oxide. The plutonium can come from reprocesssed spent fuel from other plutonium stockpiles, including dismantled weapons

fuel assemblies

a square grouping of 200 fuel rods; there are 150-250 fuel assemblies in a typical nuclear power plant

active solar heating

a system of putting the sun's energy to use in which a series of collectors absorb the solar energy, and pumps or fans distribute the collected heat

passive solar heating

a system of putting the sun's energy to use without requiring mechanical devices to distribute the collected heat

schistosomiasis

a tropical disease caused by a parasitic worm, damages the liver urinary tract, nervous system, and lungs

breeder nuclear fission

a type of nuclear fission in which nonfissionable U-238 is converted into fissionable Pu-239

solar cell

a wafer or thin film of solid-state materials, such as silicon or gallium arsenide, that is treated with certain metals so that it generates electricity - that is, a flow of electrons - when it absorbs solar energy

fuel rod

closed tubes in a nuclear reactor where the pellets of uranium dioxide are placed

wind energy

electric or mechanical energy obtained from surface air currents caused by solar warming of air

isotopes

forms of a single element that differ in atomic mass

hydrothermal reservoir

heated groundwater (in areas of geologically recent volcanism) that is trapped by an impermeable layer in Earth's crust; it contains hot water and steam that may escape to the surface creating hot springs or geysers

infrared radiation

invisible waves of heat

atomic mass

is equal to the sum of protons and neutrons in the nucleus of an element

dry cask storage

large cylinders of concrete and steel that hold 10 or more metric tons of high-level waste

control rod

located above each fuel assembly, it is made of a special metal alloy that absorbs neutrons; the movement of the control rod determines the amount of fission

Define nuclear reactor and describe a typical nuclear power reactor

nuclear reactor is a device that initiates and maintains a controlled nuclear fission chain reaction to produce energy for electricity. A typical reactor contains a reactor core, where fission occurs; a stream generator; a turbine; and a condenser; The reactor core contains fuel rods filled with pellets of uranium dioxide. Above each fuel assembly is a control rod that is moved into or out in or out of the fuel assembly, thereby producing the amount of fission required. The fission of U-235 releases heat that converts water to stream, used to generate electricity. Safety features include a containment building of steel-reinforced concrete. Conventional nuclear fission uses U-235, which makes up about 3% to 5% of uranium after enrichment, Spent fuel is the used fuel elements that were irradiated.

Explain the pros and cons of on-site storage and deep geologic disopsal

on-site storage in liquid is necessary for a short period of time, as spent fuel rods cool. However, spent rods cannot be safety stored in liquid for long periods. The National Research Council suggests that deep geologic storage is the safest and most secure long-term solution for high-level nuclear wastes. Until a storage facility is licensed and constructed, on-site dry cask storage in large, expensive steel and concrete cylinders will be increasingly common.

reactor core

one of the four main parts of the pressurized water reactor in a nuclear power plant; contains the fuel assemblies; where fission occurs

steam generator

one of the four main parts of the pressurized water reactor in a nuclear power plant; where the heat produced by the nuclear fission is used to produce steam from liquid water

condenser

one of the four main parts of the pressurized water reactor in a nuclear power plant; where the steam is cooled and converts back to a liquid

turbine

one of the four main parts of the pressurized water reactor in a nuclear power plant; where the steam is used to drive a generator that produces electricity

deuterium

one of two stable isotopes of hydrogen which contain one proton and one neutron per nucleus

entombment

permanently encasing the entire nuclear power plant in concrete

biomass

plant material, including undigested fiber in animal waste, used as fuel

Three Georges Dam (TGD)

produces most of China's electricity but displaced many people

high-level radioactive wastes

radioactive solids, liquids, or gases that give off large amounts of ionizing radiation

low-level radioactive wastes

radioactive solids, liquids, or gases that give off small amounts of ionizing radiation

tritium

radioisotope of hydrogen which contains one proton and two neutrons per nucleus

Nuclear Waste Policy Act

requires the US government to take ownership of nuclear waste

Albert Einstein

scientist who hypothesized that mass and energy are related in his now-famous equation E=mc2 in which E is equal to mass (m) times the speed of light (c) squared

vitrification

solid glass or ceramic logs of solidified liquid waste

3 options that exist when a nuclear power plant is closed (because many parts have become contaminated with radioactivity)

storage, entombment, and decommissioning

plasma

superheated, ionized gas

ocean thermal energy conversion (OTEC)

technology that takes advantage of the different temperatures in the ocean ( ocean gradients) to produce electricity or to cool buildings

biomass

term used for for plants - including wood, corn, grasses, and even plant fibers in animal dung - that are burned for their energy; it can be a controversial energy source

radioactive decay

the emission of energetic particles or rays from unstable atomic nuclei; includes positively charged alpha particles, negatively charged beta particles, and high-energy electromagnetic gamma rays

nuclear energy

the energy released by nuclear fission or fusion

fusion

the joining of two lightweight atomic nuclei into a single, heavier nucleus, accompanied by the release of a large amount of energy; the process that powers the sun and other stars

Three Mile Island

the most serious nuclear reactor accident in the US

Describe the nuclear fuel cycle, including the process of enrichment

the nuclear fuel cycle includes the processes involved in producing the fuel used in nuclear reactors and in disposing of radioactive wastes (or nuclear wastes); Enrichment, which is part of the nuclear fuel cycle, is this process by which uranium ore is refined after mining to increase the concentration of fissionable U-235,

Yucca Mountain (in Nevada)

the only permanent underground storage site for high-level radioactive waste

enrichment

the process by which uranium ore is refined after mining to increase the concentration of fissionable U-235

nuclear fuel cycle

the processes involved in producing the fuel used in nuclear reactors and in disposing of radioactive (nuclear) wastes

fission

the splitting of an atomic nucleus into tow smaller fragments, accompanied by the release of a large amount of energy; the process used by nuclear plants

radioactive half-life

the time required for one-half of the total amount of radioactive substance to change into a different material

geothermal energy

the use of energy from Earth's interior for either space heating or the generation of electricity; it is a renewable energy source

spent fuel

the used fuel elements that were irradiated in a nuclear reactor

Chernobyl

the worst nuclear reactor accident in the world happened in the former Soviet Union

decommission

to dismantle an old nuclear power plant after it closes

radioisotopes

unstable isotope which is radioactive because it spontaneously emits radiation, a form of energy consisting of particles

reprocessed

when a breeder reactor does to excess fissionable fuel to increase the concentration of Pu-239 for use as fuel

meltdown

when the metal encasing the uranium fuel melts at high temperatures releasing radiation