Ch. 9: Nonrenewable Energy Sources

Name the steps in the nuclear fuel cycle.

1) Mining and milling 2) Enrichment 3) Fuel fabrication 4) Use of the fuel 5) Reprocessing or storage 6) Transportation

Nuclear Power

Although nuclear power does not come from a fossil fuel, it is fueled by uranium that is obtained by mining. Like fossil fuels, uranium is nonrenewable. Worldwide, energy from nuclear power plants is the fifth most important energy source after coal, oil, natural gas, and hydroelectric power.

Name the three most important sources of energy.

Coal, oil, and natural gas

Tight oil

- (light tight oil) consists of a mixture of hydrocarbons with low viscosity which cannot flow because the rock containing it (shale or tight sandstone) is not porous (tight). Horizontal drilling and hydraulic fracturing are used to open channels that allow the oil to flow (hydraulic fracturing?) - The production of tight oil in North Dakota and Montana has become a major new source of crude oil for the United States.

Nuclear Fission Reactors

- A nuclear reactor is a device that permits a sustained, controlled nuclear fission chain reaction. There are four important materials that are involved in producing a controlled nuclear chain reaction: the fuel, a moderator, control rods, and the core coolant. - In the production of electricity, a nuclear reactor serves the same function as burning a fossil fuel. - It produces heat, which converts water to steam to operate a turbine that generates electricity. After passing through the turbine, the steam must be cooled, and the water is returned to the reactor to be heated again. - Various types of reactors have been constructed to furnish heat for the production of steam. - They differ in the moderator used, in how the reactor core is cooled, and in how the heat from the core is used to generate steam. - The three most common kinds of nuclear reactors are boiling-water reactors, pressurized-water reactors, and heavy-water reactors.

Air pollution and Burning of coal

- Acid deposition is one of the problems associated with the burning of coal. Acid deposition occurs when coal is burned and sulfur oxides are released into the atmosphere, causing acid-forming particles to accumulate. Each year, over 150 million metric tons of sulfur dioxide are released into the atmosphere worldwide—most comes from coal-fired power plants. - Mercury is released into the air when coal is burned, since mercury is present in the coal. Mercury is a problem because it tends to accumulate in the bodies of animals and can be in high concentrations in the bodies of predators such as fish. Thus, the federal and state governments have issued advisories on the amount and kinds of fish it is safe to consume. - Carbon dioxide and climate change are other problems associated with the burning of coal. Increasing amounts of carbon dioxide in the atmosphere are responsible for warming of the planet and the changes in climate that occur as a result. Since burning coal releases more carbon dioxide than other fossil fuels per unit of energy obtained, many industries have switched to other sources of energy.

4. Terrorism

- After the terrorist attacks on New York and Washington, D.C., on September 11, 2001, fear arose regarding nuclear plants as potential targets for terrorist attacks. - The consensus by nuclear experts is that damage to a nuclear power plant by an aircraft would not significantly damage the containment building or reactor and that normal emergency and containment functions would prevent the release of radioactive materials. - Probably the greatest terrorism-related threat involving radioactive material is from dirty bombs. Dirty bombs are also known as radiological dispersal devices (RDDs). They are not true nuclear weapons or devices but are simply a combination of conventional explosives and radioactive materials. The explosion of such a device is designed to scatter radioactive material about the environment to cause disruption and create panic rather than to kill large numbers of people

The Nature of Nuclear Energy

- All atoms are composed of a central region called the nucleus, which contains positively charged protons and neutrons that have no charge. Moving around the nucleus are smaller, negatively charged electrons. - Since like charges repel one another, some force is required to hold the positively charged protons together in the nucleus. This is called the nuclear force. In most atoms, the various forces in the nucleus are balanced, and the nucleus is stable. - However, some isotopes of atoms are radioactive; that is, the nuclei of these atoms are unstable and spontaneously decompose. - Neutrons, electrons, protons, and other larger particles are released during nuclear disintegration, along with a great deal of energy. The rate of decomposition is consistent for any given isotope. - It is measured and expressed as radioactive half-life, which is the time it takes for one-half of the radioactive material to spontaneously decompose

Tar sands

- Also referred to as oil sands) are a combination of clay, sand, water, and a thick oil called bitumen. The bitumen is so thick that it cannot be pumped from the ground but must be mined—usually an open pit or strip mine. The mixture of bitumen and sand must be processed to extract the bitumen, which then must be altered to produce oil that will flow through a pipeline. All of the steps in this process take energy. The net return on energy is about 5 to 1. In other words, for every unit of energy put into the process you get back about five units. - Although tar sands are found in many places in the world, the only major commercial production of oil from tar sands is in Alberta, Canada - The production of oil from tar sands in Alberta became a political issue when a Canadian pipeline company proposed the Keystone XL pipeline that would carry oil from Alberta through Montana, Kansas, and Nebraska to Steele City, Nebraska. - President Obama ultimately halted the building of the pipeline. President Trump reversed that decision by executive and approved its construction in 2017.

Oil- Environmental Issues Pt. 1

- Although there are disturbances to the land at the drilling site, oil spills are the primary environmental problem associated with the production, transportation, and use of oil. Since oil is a liquid, it is generally moved from place to place through pipes. If these pipes break or leak, the oil contaminates the soil, groundwater, or surface water. This can happen anywhere from the drilling site to where the oil is used. - Oil spills in the oceans from supertankers have been widely reported by the news media. Because of new regulations, changes in tanker hull design, and greater attention to safety, the number of tanker spills has declined over the last few decades, while the amount of oil being transported has increased. - it is estimated that worldwide only about 10 percent of human-caused oil pollution comes from tanker accidents. - The use of platforms to drill oil wells on the ocean floor has resulted in some huge oil spills. - Since 1955, there have been about 50 failures or accidents on ocean drilling rigs that have resulted in the release of oil and natural gas into the ocean. - The two largest occurred in the Gulf of Mexico. 1. In 1979, the Ixtoc 1 oil spill is estimated to have released about 700 metric tons of oil. 2. In 2010, the Deepwater Horizon oil rig caught fire and sank. It is estimated that about 10,000 metric tons of oil were released before it was eventually sealed. This is the largest oil spill on record.

Current Status of Nuclear Power

- As of July 2017, there were 447 nuclear power reactors in operation. They accounted for about 11 percent of the electrical energy generated in the world. - There were also 59 nuclear power plants under construction in 14 countries. - A further 160 were in the planning stages. Most are in Asia, where China, India, Japan, and South Korea were projected to add about 68 new plants over the next ten years. Russia has plans for an additional 26 plants, and electric utilities in the United States have requested approval for 16 new plants - The US has 99 operating nuclear power plants, about 22% of the world total

Coal Transportation Issues

- Because coal is bulky, shipping presents a problem. Generally, the coal can be used most economically near where it is produced. - Rail shipment is the most economic way of transporting coal from the mine. - Rail shipment costs include the expense of constructing and maintaining the tracks, as well as the cost of the energy required to move the long strings of railroad cars. - In some areas, the coal is transferred from trains to ships

Coal Extraction Methods

- Because coal was formed as a result of plant material being buried under layers of sediment, it must be mined. - There are two methods of extracting coal: surface mining and underground mining. 1. Surface mining (strip mining) involves removing the material located on top of a vein of coal, called overburden, to get at the coal beneath - Coal is usually surface mined when the overburden is less than 100 meters (328 feet) thick. - This type of mining operation is efficient because it removes most of the coal in a vein and can be profitably used for a seam of coal as thin as half a meter. - For these reasons, surface mining results in the best utilization of coal reserves. - Advances in the methods of surface mining and the development of better equipment have increased surface-mining activity in the United States from 30 percent of the coal production in 1970 to about 65 percent today. 2. Underground mining: If the overburden is thick, surface mining becomes too expensive, and the coal is extracted through underground mining - The deeply buried coal seam can be reached in two ways. In flat country where the vein of coal lies buried beneath a thick overburden, the coal is reached by a vertical shaft. - In hilly areas where the coal seam often comes to the surface along the side of a hill, the coal is reached from a drift-mine opening.

Chernobyl 1986

- Chernobyl is a small city in Ukraine north of Kiev that became infamous in the spring of 1986, when it became the site of the world's largest nuclear power plant accident. - At 1 a.m. on April 25, 1986, at Chernobyl Nuclear Power Station-4, a test was begun to measure the amount of electricity that the still-spinning turbine would produce if the steam were shut off. This was important information since the emergency core cooling system required energy for its operation, and the coasting turbine could provide some of that energy until another source became available. - During the experiment, operators violated six important safety rules. They shut off all automatic warning systems, automatic shutdown systems, and the emergency core cooling system for the reactor - As the test continued, the power output of the reactor rose beyond its normal level and continued to rise. The operators activated the emergency system that was designed to put the control rods back into the reactor and stop the fission. But it was too late. The core had already been deformed, and the control rods would not fit properly; the reaction could not be stopped. In 4.5 seconds, the energy level of the reactor increased 2,000 times. The cooling water in the reactor converted to steam and blew the 1,000-metric ton (1,102-ton) concrete roof from the reactor, and the graphite that was part of the reactor core caught fire. - It took 10 days to bring the burning reactor under control. The immediate consequences were 37 fatalities; 500 persons hospitalized, including 237 with acute radiation sickness; and 116,000 people evacuated. Of the evacuees, 24,000 received high doses of radiation. Currently, some of these people are experiencing health problems attributable to their radiation exposure. In particular, children or fetuses exposed to fallout are showing increased frequency of thyroid cancer because of exposure to radioactive iodine 131 released from Chernobyl. - Work to contain the damaged reactor has been ongoing for 30 years. A major milestone was reached in November 2016 when a permanent containment structure was moved into position over the damaged reactor. The containment structure will prevent the release of contaminated material from the hastily constructed temporary shelter and provide protection from the weather.

Coal Use

- Coal is the world's most abundant fossil fuel, but it supplies less than 30 percent of the energy used in the world - It varies in quality and is generally classified in four categories: lignite, sub-bituminous, bituminous, and anthracite. - Lignite (brown) coal has a high moisture content and is crumbly, which makes it the least desirable form. It has a low energy content that makes transportation over long distances uneconomical. Therefore, most lignite is burned in power plants built near the coal mine. Over 60 percent of the lignite used is from Europe. - Sub-bituminous coal has a lower moisture content and a higher carbon content (46-60 percent) than lignite and is typically used as fuel for electric power plants. - Bituminous (soft) coal has a low moisture content and a high carbon content (60-86 percent). It is primarily used in electrical power generation but is also used in other industrial applications such as cement production and steelmaking. Bituminous coal is the most widely used because it is the easiest to mine and the most abundant. It supplies about 20 percent of the world's energy requirements. - Anthracite (hard) coal is 86-98 percent carbon. It is relatively rare and is used primarily in heating of buildings and for specialty uses.

Formation of Coal

- Coal was formed from plant material that had been subjected to heat and pressure - Freshwater swamps covered many regions of the Earth 300 million years ago. Conditions in these swamps favored extremely rapid plant growth, resulting in large accumulations of plant material. Because this plant material collected under water, decay was inhibited, and a spongy mass of organic material formed. It is thought that the chemical nature of these ancient plants and the lack of many kinds of decay organisms at that time also contributed to the accumulation of plant material. - Due to geologic changes in the Earth, some of these organic deposits were submerged by seas. The plant material that had collected in the swamps was then covered by sediment. The weight of the sediment on top of the deposit compressed it, and heat from the Earth caused the evaporation of water and other volatile compounds. Thus, the original plant material was transformed into coal. - Depending on the amount of time the organic matter has been subjected to geologic processes, several different grades of coal are produced.

Coal- Air pollution

- Dust is generated by mining and transportation of coal. The large amounts of coal dust released into the atmosphere at the loading and unloading sites can cause local air pollution problems. If a boat or railroad car is used to transport coal, there is the expense of cleaning it before other types of goods can be shipped. - Air pollution from coal burning releases millions of metric tons of material into the atmosphere and is responsible for millions of dollars of damage to the environment. The burning of coal for electric generation is the prime source of this type of pollution.

2. Enrichment

- Enrichment of the U-235 content is necessary because naturally occurring uranium contains about 99.3 percent nonfissionable U-238 and only 0.7 percent fissionable U-235. - This concentration of U-235 is not high enough for most types of reactors. Since the masses of the isotopes U-235 and U-238 vary only slightly, and the chemical differences are very slight, enrichment is a difficult and expensive process. - The enrichment process involves the use of centrifuges to separate the two isotopes of uranium by their slight differences in mass. - Enrichment increases the U-235 content from 0.7 percent to 3 percent

Coal Health and Safety Issues

- Health and safety are important concerns related to coal mining, particularly in underground mines. - Explosions of methane gas and Page 200accidents kill many miners each year. In the United States during the decade of 2006-2015, there was an average of 26.5 deaths per year and about 3,600 injuries per year related to coal mining. The majority of the deaths and injuries were in underground mines. - Many miners suffer from black lung disease, a respiratory condition that results from the accumulation of fine coal-dust particles in the miners' lungs. (Over 8 percent of miners who worked 25 or more years in mines tested positive for black lung disease.) The coal particles inhibit the exchange of gases between the lungs and the blood. - The healthcare costs and death benefits related to black lung disease are an indirect cost of coal mining. Since these healthcare costs are partially paid by the federal government, the total healthcare cost is not reflected in the price of coal but is paid by taxpayers in the form of federal taxes and higher health insurance premiums.

Nuclear Chain Reaction

- In addition to releasing alpha, beta, and gamma radiation when they disintegrate, the nuclei of a few kinds of atoms release neutrons. When moving neutrons hit the nuclei of certain other atoms, they can cause those nuclei to split as well. An atom that has a nucleus that will split is said to be fissionable, and the process of splitting is known as nuclear fission - If these splitting nuclei also release neutrons, they can strike the nuclei of other atoms, which also disintegrate, resulting in a continuous process called a nuclear chain reaction - Only certain kinds of atoms are suitable for the development of a nuclear chain reaction. The two materials commonly used in nuclear reactions are uranium-235 and plutonium-239. - In addition, there must be a certain quantity of nuclear fuel (a critical mass) in order for a nuclear chain reaction to occur. - It is this process that results in the large amounts of energy released from nuclear weapons or nuclear reactors

3. Fuel Fabrication

- Involves converting the enriched material into a powder, which is then compacted into pellets about the size of a pencil eraser. - These pellets are sealed in metal fuel rods about 4 meters (13 feet) in length, which are loaded into a reactor.

1. Mining and milling

- Mining and milling of uranium ore are the first steps in the nuclear fuel cycle. - Low-grade uranium ore is obtained by underground or surface mining. The ore contains about 0.2 percent uranium by weight. - After it is mined, the ore goes through a milling process. It is crushed and treated with a solvent to concentrate the uranium. - Milling produces yellow-cake, a material containing 70 to 90 percent uranium oxide. - About 20 countries produce uranium with Kazakhstan, Canada, Australia, and Niger providing nearly 75 percent of the total.

Radiation types

- Nuclear disintegration releases energy from the nucleus as radiation, of which there are three major types: 1. Alpha radiation 2. Beta radiation 3. Gamma radiation

Natural Gas- Environmental Issues

- Of the three fossil fuels, natural gas is the least disruptive to the environment. - A natural gas well does not produce any unsightly waste, although there may be local odor problems. Except for the danger of an explosion or fire, natural gas poses no harm to the environment during transport. - Since it is clean burning, it causes almost no air pollution. - The products of its combustion are carbon dioxide and water. Although the burning of natural gas produces carbon dioxide, which is a greenhouse gas, it produces less carbon dioxide per unit of energy obtained than does coal or oil. - Although natural gas is used primarily for heat energy, it does have other uses, such as the manufacture of petrochemicals and fertilizer. - Methane contains hydrogen atoms that are combined with nitrogen from the air to form ammonia, which can be used as fertilizer.

Processing Crude Oil

- Oil, as it comes from the ground, is not in a form suitable for most uses. It must be refined. - The various components of crude oil can be separated and individually collected by heating the oil in a distillation tower. After distillation, the products may be further refined Page 203by "cracking." - In this process, heat, pressure, and catalysts are used to produce a higher percentage of volatile chemicals, such as gasoline, from less volatile liquids, such as diesel fuel and furnace oils. - In addition, the refining process may be used to produce petrochemicals that serve as raw materials for a variety of synthetic compounds such as plastics, fabrics, paints, and rubber

Fukushima Dai-ichi 2011

- On March 11, 2011, a magnitude 9 earthquake 130 km off the northeast coast of Japan triggered the automatic shutdown of several nuclear reactors in the vicinity of the earthquake. The subsequent tsunami flooded the site at Fukushima Dai-ichi - The heat exchangers were damaged, power to the site was cut off, and the diesel generators designed to provide power in an emergency were flooded and stopped operating. The reactors at Fukushima Dai-ichi were older, boiling-water reactors that required electrical power to pump cooling water through them to remove heat during the shutdown process. At the time of the earthquake and tsunami, there were six reactors in operation and three were shut down for refueling or maintenance. Each of the six reactors also had a spent fuel storage site adjacent to the reactor. - the loss of the ability to cool the reactors and their adjacent spent fuel storage sites resulted in explosions and fires that were caused by the release of hydrogen from the overheated reactors and one of the spent fuel storage sites. At one point, seawater was used to supply cooling water, but as power was restored and the pumping mechanisms repaired or replaced, freshwater was again used for cooling. By the end of April 2011, the reactors and spent fuel storage sites were considered stable, but four of the six reactor units were so badly damaged that they will need to be decommissioned. The decommissioning process will take 30 to 40 years to complete. - The explosions, fires, and leaks in the cooling system released radiation into the atmosphere and seawater. People living within 20 km of the plant were urged to evacuate and take iodine supplements to reduce the likelihood that radioactive iodine-131 would accumulate in the thyroid gland. Crops and milk from the affected area were banned from sale to reduce the likelihood of exposure to airborne radioactive materials. Since iodine-131 has a half-life of 8 days, its levels fall quickly. However, two other radioactive isotopes, cesium-134 and cesium-137, have half-lives of 2 years and 30 years, respectively.

Different types of Coal

- Peat is recently dead plant material that has been altered very little and has a high moisture content. - Lignite, sub-bituminous, bituminous, and anthracite coal have progressively less water and higher carbon content. From left to right --> increasing burial pressure, heat and time

Forces that Influence the Growth of Nuclear Power

- Primary among them are environmental and economic issues that become transformed by the political process into governmental policy. Plans to decommission plants, extend the life of plants, or build new plants are political decisions made by national governments in light of the opinions of their citizens. In many parts of the world, there is a strong anti-nuclear sentiment. There are many reasons people take an anti-nuclear stance. Some oppose all things nuclear because they see it as a threat to world peace. Others are concerned about the environmental issues of potential nuclear contamination and the problem of waste disposal. - Since nuclear power plants do not produce carbon dioxide, many people, including some environmental organizations, have reevaluated the value of nuclear power and see it as a continuing part of the energy equation. - When the cost of oil and natural gas has increased, electricity generation from these sources has become more costly. This has made nuclear power more attractive. Countries that have few fossil-fuel reserves and those with developing economies are most likely to build nuclear power plants. - For example, Australia, New Zealand, Denmark, Ireland, Portugal, Luxembourg, Greece, and Austria have declared that they will not pursue nuclear Page 206energy as an option.

5. Reprocessing or storage

- Reprocessing or storage are the two options available for spent fuel rods. Reprocessing involves extracting the remaining U-235 and plutonium from the spent fuel, separating the U-235 from the plutonium, and using both to manufacture new fuel rods. - The plutonium is mixed with spent uranium (mostly U-238) to form a mixed oxide fuel that can be used as a fuel in some kinds of nuclear power plants. Besides providing new fuel, reprocessing reduces the amount of nuclear waste. - About 40 percent of the spent fuel produced each year is sent to reprocessing plants. - Those countries that do not reprocess nuclear waste have made the decision to store it. Initially, the waste is stored onsite at the nuclear power plant, but the long-term plan is to bury the waste in stable geologic formations.

Coal- Acid mine drainage

- Since coal is a fossil fuel formed from plant remains, it contains sulfur, which was present in the proteins of the original plants. Sulfur is associated with acid mine drainage and air pollution. - Acid mine drainage occurs when the combined action of oxygen, water, and certain bacteria causes the sulfur in coal to form sulfuric acid. Sulfuric acid can seep out of a vein of coal even before the coal is mined. - However, the problem becomes worse when the coal is mined and the overburden is disturbed, allowing rains to wash the sulfuric acid into streams. - Streams may become so acidic that they can support only certain species of bacteria and algae. - Today, many countries regulate the amount of runoff allowed from mines, but underground and surface mines abandoned before these regulations were enacted continue to contaminate rivers and streams.

Oil Extraction

- Since the many easy-to-reach oil fields have already been tapped, drilling now focuses on smaller amounts of oil in less accessible sites, which means that the cost of oil from most recent discoveries is higher than that from the large, easy-to-locate sources of the past. - As oil deposits located below land have become more difficult to find, geologists have widened the search to include the ocean floor. Building an offshore drilling platform can cost millions of dollars. To reduce the cost, as many as 70 wells may be drilled from a single platform. - When the natural pressure is not great enough, the oil must be pumped to the surface. These techniques are often referred to as primary recovery methods and can extract 5 to 30 percent of the oil depending on geologic characteristics of the source and the viscosity of the oil. - In most oil fields, secondary recovery is used to recover more of the oil. Secondary recovery methods include pumping water or gas into the well to drive the oil out of the pores in the rock. These techniques typically result in up to 40 percent of the oil being extracted. As oil prices increase, more expensive and aggressive recovery methods become economical. - Tertiary recovery methods include pumping steam into the well to lower the viscosity of the oil and allow it to flow more readily. - Other techniques include more aggressive pumping of gases or chemicals into wells. - All of these methods are expensive and are only used if the price of oil is high and the likelihood of getting significant additional production is great.

Coal- Landscape disturbance

- Surface mining (strip mining) disrupts the landscape, as the topsoil and overburden are moved to access the coal. - One of the most controversial surface-mining methods is mountaintop removal. In this method, the top of a mountain is removed to get at the coal vein, and the unwanted soil and rock are pushed into the adjacent valley. Additional problems besides disturbance of landscape. For example, valleys have streams that drain them, and the soil and rock that are pushed into the valley contaminate the water. - It is possible to minimize the effect of landscape disturbance by reclaiming the area after mining operations are completed. (See figure 9.9.) However, reclamation rarely, if ever, returns the land to its previous level of productivity. - The cost of reclamation is included in the price of coal, so mining companies often seek to do as little as possible. - Underground mining methods do not disrupt the surface environment as much as surface mining does, but subsidence (sinking of the land) occurs if the mine collapses. - The processing of coal requires that it be washed before being shipped. This results in the production of a liquid waste material known as coal slurry. It is a mixture of coal and other particles and water. Typically this liquid waste is stored at the processing site behind dams in open ponds. Leakage from such ponds pollutes local streams, and failure of the dams has caused floods.

Three Mile Island 1979

- The Three Mile Island nuclear plant is located in the Susquehanna River near Middletown, Pennsylvania. On March 28, 1979, the main pump that supplied cooling water to the reactor broke down. - At this point, an emergency coolant should have flooded the reactor and stabilized the temperature. - The coolant did start to flow into the reactor core, but a pressure relief valve was stuck in the open position so that water also was flowing from the core. - In addition, there was no sensor to tell the operator if the reactor was flooded with coolant. Relying on other information, the operator assumed the reactor core was flooded and overrode the automatic emergency cooling system. Without the emergency coolant, the reactor temperature rose rapidly. - The control rods eventually stopped fission in the reactor, but because of the loss of coolant, a partial core meltdown had occurred. - Thus, the accident was caused by a combination of equipment failures, lack of appropriate information to the operator, and decisions by the operator. - However, in retrospect, the containment structure worked as designed and prevented the release of radioactive materials from the core. - Will be decommissioned once it's companion reactor reaches the end of its useful life

Measuring Radiation

- The amount of radiation absorbed by the human body is a way to quantify the potential damage to tissues from radiation. - The absorbed dose is the amount of energy absorbed by matter. It is measured in grays or rads. - However, the damage caused by alpha particles is 20 times greater than that caused by beta particles or gamma rays. - Therefore, a dose equivalent is used. The dose equivalent is the absorbed dose times a quality factor. - units for dose equivalents are seiverts or rems. - The quality factor for beta and gamma radiation is 1. Therefore, the dose equivalent is the same as the absorbed dose. The quality factor for alpha radiation is 20. Therefore, the dose equivalent for alpha radiation is 20 times the absorbed dose.

5. Nuclear waste disposal

- The disposal of nuclear waste from power plants is a major concern. There are really only two alternatives: reprocessing the waste from fuel or placing the waste in a secure location. - Several nations use reprocessing to reduce the amount of nuclear waste. Others rely on temporary storage at nuclear plants. Ultimately, these wastes will need to be placed in long-term storage underground.

Natural Gas- Extraction Methods

- The drilling operations to obtain natural gas are similar to those used for oil. In fact, a well may yield both oil and natural gas - As with oil, secondary recovery methods that pump air or water into a well are used to obtain the maximum amount of natural gas from a deposit (Hydraulic fracturing) - After processing, the gas is piped to the consumer for use.

Oil- Environmental Issues Pt. 2

- The environmental damage caused by oil spills is related to several factors, including the amount of oil released, the size of the area affected, the climate and weather, and other factors - The oil on the ocean surface can coat birds, reptiles, and mammals that must surface to breathe. Since the oil is toxic, fish and other marine life that consume oil can be affected. When the oil reaches the shore it coats surfaces and kills vegetation and marine life along the shore, and it also makes the area unsuitable for swimming, boating, fishing, and other human uses. - The vast majority (85%) of the oil entering the oceans results from natural seeps and pollution from the use of oil as lubricants and fuel in machinery (ocean ships, personal watercraft, cars, trucks, lawn mowers, etc.). The residue from these uses washes into streams and is carried to the oceans. - Sources of Oil Entering Oceans: Natural seeps: 47% Consumption activities (Cars, boats, etc.): 38% Transport of Oil: 12% Ocean Oil Drilling: 3% - The evaporation of oil products and the incomplete burning of oil fuels contribute to air pollution.

6. Decommissioning Nuclear Power Plants

- The life expectancy for an electrical generating plant, whether fossil fuel or nuclear, is about 30 to 40 years, after which time the plant is taken out of service. - nuclear plants are not demolished; they are decommissioned. Decommissioning involves removing the fuel, cleaning surfaces, and permanently preventing people from coming into contact with the contaminated buildings or equipment. -The decommissioning of a plant is a two-step process: Stage 1 involves removing fuel rods and water used in the reactor and properly storing or disposing of them. This removes 99 percent of the radioactivity. The radioactive material remaining consists of contaminants and activated materials. Activated materials are atoms that have been converted to radioactive isotopes as a result of exposure to radiation during the time the plant was in operation. These materials must be dealt with before the plant can be fully decommissioned. Stage 2 leads to the final disposition of the facility. There are three options to this second stage of the decommissioning process. 1. Decontaminate and dismantle the plant as soon as it is shut down. 2. Secure the plant for many years to allow radioactive materials that have a short half-life to disintegrate and then dismantle the plant. (However, this process should be completed within 60 years.) 3. Entomb the contaminated portions of the plant by covering the reactor with reinforced concrete and placing a barrier around the plant. (Currently this option is only considered suitable for small research facilities.)

Coal Reserves (2015)

- The majority of the coal deposits of the world are in North America, Europe, Eurasia, and the Asia/Pacific regions. World: 891.5 (thousand million metric tons) Europe and Eurasia: 310.5 Asia Pacific: 288.3 North America: 245.1 Africa: 31.7 South and Central America: 14.6 Middle East: 1.1

Coal Environmental Issues

- The mining, transportation, and use of coal as an energy source present several significant environmental problems. 1. Landscape disturbance: 2. Acid mine drainage: 3. Air pollution

Resource vs. Reserve

- The total amount of a resource such as coal or oil changes only by the amount used each year. The amount of a reserve changes as technology advances, new deposits are discovered, and economic conditions vary. - Furthermore, countries often restate the amount of their reserves for political reasons. Thus, there can be large increases in the amount of reserves, while the total amount of the resource falls. - When we read about the availability of fossil fuels, we must remember that if the cost of removing and processing a fuel is greater than the fuel's market value, no one is going to produce it. - Also, if the amount of energy used to produce, refine, and transport a fuel is greater than the energy produced when it is burned, the fuel will not be produce - in the future, new technology or changing prices may permit the profitable removal of some fossil fuels that currently are not profitable. If so, those resources will be reclassified as reserves.

2. Radiation Protection

- Time, distance, and shielding are the basic principles of radiation protection. The basic idea behind these three principles is that the total cumulative dose should be minimized 1. Time is important because the longer one is exposed to a source of radiation, the more radiation is absorbed. 2. Distance is important because the farther a person is from the source, the less likely that person will be hit by radiation. In addition, alpha and beta radiation will only travel a short distance through air. 3. Shielding is important because it can stop radiation and prevent a person from being exposed. Because gamma radiation can travel many meters through air and can penetrate the body, shielding is very important. Water, lead, and concrete are common materials used for shielding from gamma radiation. - shielding from isotopes involves such devices as masks, gloves, and protective clothing - These kinds of devices measure past exposure to radiation, which can be useful in determining whether a person should avoid future exposure. This is most important for people who work in environments that have a radiation hazard.

Natural Gas- Transport Methods

- Transport of natural gas still presents a problem in some parts of the world. - In the Middle East, Mexico, Venezuela, and Nigeria, wells are too far from consumers to make pipelines practical, so much of the natural gas is burned as a waste product at the wells. - However, new methods of transporting natural gas and converting it into other products are being explored. - At -162°C (-126°F), natural gas becomes a liquid and has only 1/600 of the volume of its gaseous form. Tankers have been designed to transport liquefied natural gas from the area of production to an area of demand. - In 2015, about 338 billion cubic meters (about 12,000 billion cubic feet) of natural gas were shipped between countries as liquefied natural gas. This is about 10 percent of the natural gas consumed in the world. - A major public concern about liquefied natural gas is the safety at loading and unloading facilities. - When new ports are suggested, there is concern about explosions that could result from accidents or the actions of terrorists. Because of these concerns, the loading and unloading facilities are often located several kilometers offshore.

6. Transportation

- Transportation is involved in each step in the nuclear fuel cycle. - The uranium mines are some distance from the processing plants. The fuel rods must be transported to the power plants, and the spent rods must be moved to a reprocessing plant or storage area. - Each of these links in the fuel cycle presents the possibility of an accident or mishandling that could release radioactive material. - Therefore, the methods of transport are very carefully designed and tested before they are used, and there has never been a significant release of radioactive material as a result of a transportation incident.

4. Use of the Fuel

- Use of the fuel in a reactor results in a decrease in the amount of U-235 in the fuel rods over time. After about three years, a fuel rod does not have enough radioactive material to sustain a chain reaction, and the spent fuel rods must be replaced by new ones. - The spent rods are still very radioactive, containing about 1 percent U-235 and 1 percent plutonium. Because spent fuel rods are radioactive, they must be managed carefully to prevent environmental damage and risks to health.

1. Biological Effects of Ionizing Radiation

- When an alpha or beta particle or gamma radiation interacts with atoms, it can dislodge electrons from the atoms and cause the formation of ions. - Therefore, these kinds of radiation are called ionizing radiation. (X rays are also a form of ionizing radiation, although they are not formed as a result of nuclear disintegration.) - When ionization occurs in living tissue it can result in damage to DNA or other important molecules in cells. -The degree and kind of damage vary with the kind of radiation, the amount of radiation, the duration of the exposure, and the types of cells irradiated. - Because ionizing radiation affects DNA, it can cause mutations, which are changes in the genetic messages within cells. Mutations can cause two quite different kinds of problems. 1. Mutations that occur in the ovaries or testes can form mutated eggs or sperm, which can lead to abnormal offspring. Care is usually taken to shield these organs from unnecessary radiation 2. Mutations that occur in other tissues of the body may manifest themselves as abnormal tissue growths known as cancer. Two common cancers that are strongly linked to increased radiation exposure are leukemia and breast cancer. Because mutations are essentially permanent, they may accumulate over time. Therefore, the accumulated effects of radiation over many years may result in the development of cancer later in life - he higher the dose, the higher the incidence of abnormality. Lower doses may cause temporary cellular changes, but it is difficult to demonstrate long-term effects.

Oil Use

- Worldwide about 33 percent of the energy consumed comes from oil. - Oil has several characteristics that make it superior to coal as a source of energy. - Its extraction causes less environmental damage than does coal mining. - It is a more concentrated source of energy than coal, it burns with less pollution, and it can be moved easily through pipes. - About 70 percent of the oil used in the United States is as gasoline or diesel fuel for vehicles. - Today, geologists use a series of tests to locate underground formations that may contain oil. When a likely area is identified, a test well is drilled to determine if oil is actually present

Heavy-water reactors

- a third type of reactor that uses water as a coolant. - This type of reactor was developed by Canadians and uses water that contains the hydrogen isotope deuterium in its molecular structure as the reactor-core coolant and moderator. Since the deuterium atom is twice as heavy as the more common hydrogen isotope, the water that contains deuterium weighs slightly more than ordinary water. - Heavy-water reactors are similar to pressurized-water reactors in that they use a steam generator to convert regular water to steam in a secondary loop. - The major advantage of a heavy-water reactor is that naturally occurring uranium isotopic mixtures serve as a suitable fuel, while other reactors require that the amount of U-235 be enriched to obtain a suitable fuel. - This is possible because heavy water is a better neutron moderator than is regular water. - Since it does not require enriched fuel, the cost of producing fuel for a heavy-water reactor is less than that for other reactors. About 10 percent of nuclear reactors are of this type.

Reserves

- are known deposits from which materials can be extracted profitably with existing technology under prevailing economic conditions. - Thus, reserves are a portion of the total resource. - the concept of reserves is an economic idea and is only loosely tied to the total quantity of a material present in the world.

Nuclear breeder reactors

- are nuclear fission reactors that form new nuclear fuel as they operate to produce electricity. - Because the process requires fast-moving neutrons, water cannot be used as a moderator because it slows the neutrons too much, and most models of breeder reactors function without a moderator. - Because it is necessary to move heat away from the reactor core very efficiently, most breeder reactors use liquid metal (often liquid sodium) as a core coolant. - Thus, they are often called liquid metal fast-breeder reactors. When a fast-moving neutron hits a nonfissionable uranium-238 (U-238) nucleus and is absorbed, an atom of fissionable plutonium-239 (Pu-239) is produced. - Remember that U-235 is a nuclear fuel and U-238 is not. Thus, a breeder reactor converts a nonfuel (U-238) into a fuel (Pu-239). - During the early stages of the development of nuclear power plants, breeder reactors were seen as the logical step after nuclear fission development because they would reduce the need for uranium, which is a nonrenewable material. - However, most breeder reactors are considered experimental, and because they produce plutonium-239, which can be used to produce nuclear weapons, they are politically sensitive.

Oil Shale

- contains a high-viscosity mixture of hydrocarbons that must be heated to extract the oil. - Typically the shale is mined and transported to a processing site. Because the cost of producing oil from oil shale is high, few countries have developed oil shale processing plants.

Gas-cooled reactors

- developed by atomic scientists in the United Kingdom. - Carbon dioxide serves as a coolant for a graphite-moderated core. As in the heavy-water reactor, natural isotopic mixtures of uranium are used as a fuel. However, this is not a popular type of reactor. - China is the only country that plans to build one in the near future.

Formation of Oil

- like coal, are products from the past. - They probably originated from microscopic marine organisms. When these organisms died and accumulated on the ocean bottom and were buried by sediments, their breakdown released oil droplets. - Gradually, the muddy sediment formed rock called shale, which contained dispersed oil droplets. Although shale is common and contains a great deal of oil, extraction from shale is difficult because the oil is not concentrated. - In recent years, the application of hydraulic fracturing technology has greatly increased the amount of oil and natural gas that can be obtained from shale. - However, in instances where a layer of porous sandstone formed on top of the oil-containing shale and an impermeable layer of rock formed on top of the sandstone, concentrations of oil often form. Usually, the trapped oil does not exist as a liquid mass but rather as a concentration of oil within sandstone pores, where it accumulates because water and gas pressure force it out of the shale. These accumulations of oil are more likely to occur if the rock layers were folded by geological forces. World: 1,697.6 (billion barrels of oil) North America: 238 Middle East: 803.5 Europe and Eurasia: 155.2 Africa: 129.1

Formation of Natural Gas

- like coal, are products from the past. Natural gas, like oil, forms from fossil remains - If the heat generated within the Earth reached high enough temperatures, natural gas could have formed along with or instead of oil. This would have happened as the organic material changed to lighter, more volatile (easily evaporated) hydrocarbons than those found in oil. - The most common hydrocarbon in natural gas is methane (CH4). - Water, liquid hydrocarbons, and other gases may be present in natural gas as it is pumped from a well. - The conditions that led to the formation of oil and gas deposits were not evenly distributed throughout the world. - The Middle East has nearly 50 percent of the world's oil reserves. Eurasia (primarily Russia and Turkmenistan ) and the Middle East have about 70 percent of the world's natural gas reserves World: 186.9 (trillion cubic meters) Middle East: 80.0 Europe and Eurasia: 56.8 North America: 12.8

Fossil fuels

- oil, coal, and natural gas, which supply about 80 percent of the world's energy. - Fossil fuels were formed hundreds of millions of years ago. They result from the accumulation of energy-rich organic molecules produced by organisms as a result of photosynthesis over millions of years. We can think of fossil fuels as concentrated, stored solar energy. - The rate of formation of fossil fuels is so slow that no significant amount of fossil fuels will be formed over the course of human history - Since we are using these resources much faster than they can be produced and the amount of these materials is finite, they are known as nonrenewable energy sources - in the future as fossil-fuel supplies become more rare, civilizations may be able to make adjustments involving improved efficiency, development of fusion energy, and expanded use of renewable energy sources that will be able to replace fossil fuels. - Fossil fuels are the remains of once-living organisms that were preserved and altered as a result of geologic forces. Significant differences exist between the formation of coal and the formation of oil and natural gas.

Renewable energy sources

- replenish themselves or are continuously present as a feature of the solar system. - Renewable energy sources currently provide about 12 percent of the energy used worldwide primarily from hydroelectricity and firewood

Pressurized-water reactors

- use water as a moderator and reactor-core coolant. However the reactor and the cooling water are contained within a vessel so that the water is kept under high pressure and steam is not allowed to form in the reactor. - A secondary loop transfers the heat from the pressurized water in the reactor to a steam generator. The steam is used to turn the turbine and generate electricity. Such an arrangement reduces the risk of radiation in the steam but adds to the cost of construction by requiring a secondary loop for the steam generator. - About 65 percent of the nuclear reactors in the world are pressurized-water reactors. Over 80 percent of the reactors currently under construction are of this type.

Boiling-water reactors

- use water as both a moderator and a reactor-core coolant. Steam is formed within the reactor and transferred directly to the turbine, which spins to generate electricity. - A disadvantage of the boiling-water reactor is that the steam passing to the turbine must be treated to remove any radiation. Even then, some radioactive material is left in the steam; therefore, the generating building must be shielded. - About 17 percent of the nuclear reactors in the world are boiling-water reactors.

What is a nuclear chain reaction?

A nuclear chain reaction occurs when the neutrons released from a splitting nucleus strike the nuclei of other atoms causing those atoms to split. This results in more neutrons being released which causes other atoms to split, thus causing a chain reaction

Describe how a nuclear power plant generates electricity.

A nuclear power plant generates electricity when the nuclei of radioactive atoms disintegrate and release energy which is used to heat water and produce steam. The steam turns a turbine that generates electricity

Recent concerns about climate change have begun to revive the nuclear industry in the United States. Do you think nuclear power should be used instead of coal for generating electricity? Why?

Coal has been used for decades to produce electricity. Coal is cheaper and abundantly available, so most of the nations rely on it. However, the following are concerns with the use of coal for generation of electricity: - pollution caused by coal using power stations. Carbon dioxide released in to the atmosphere, and its associated sulfur dioxide which causes acid rain - the availability of coal is gradually decreasing. It's high time to find an alternative energy resource Nuclear energy is the best alternative for coal energy. However, there are several concerns the public expresses over nuclear reactors. A coal fired plant releases 100x more radioactive material than a nuclear reactor. The pollution released by a coal fired plant is released directly into the environment. While nuclear plants are highly responsible for even a minor leakage of radioactive material, coal fired plants are least bothered about their releases. The new generation nuclear reactors are safer and cost effective compared to coal plants.

Describe the geologic processes that resulted in the formation of coal.

Coal is formed when large quantities of plant material from swamps are trapped in sediment and subjected to heat and pressure

Nuclear reactor: Control rods

Control rods contain nonfissionable materials that absorb the neutrons produced by fissioning uranium and prevent the neutrons from splitting other atoms. Moving the control rods into the reactor reduces the number of neutrons available to cause fission, and the reaction slows. If the control rods are withdrawn, more fission occurs, and more particles, radiation, and heat are produced.

Describe the differences between lignite, bituminous, and anthracite coal.

Depending on the amount of time the organic plant material is trapped in the earth determines the type of coal. Lignite is the lowest quality because of its high moisture content. Bituminous or soft coal has the low moisture content but is abundant whereas anthracite has the highest carbon content (energy) however is rare

Describe three factors that can cause the amount of an oil reserve to increase.

Economic conditions, technological advancement, and new deposits discovered changes the amount of oil reserves

What environmental concern has caused people to be more accepting of nuclear power?

Global warming caused by release of greenhouse gases by burning fossil fuels has caused people to look to nuclear power for a "greener" solution

Resource vs. Reserve History

History: When the first oil well in North America was drilled in Pennsylvania in 1859, it greatly expanded the estimate of the amount of Page 197oil in the Earth. There was a sudden increase in the known oil reserves. In the years that followed, new deposits were discovered. Better drilling techniques led to the discovery of deeper oil deposits, and offshore drilling established the location of oil under the ocean floor. At the time of their discovery, these deep deposits and the offshore deposits added to the estimated size of the world's oil resources. But they did not necessarily add to the reserves because it was not always profitable to extract the oil. With advances in drilling and pumping methods and increases in oil prices, it eventually became profitable to obtain oil from many of these deposits.

Given what you know about the economic and environmental costs of different energy sources, would you recommend that your local utility company use nuclear power or coal to supplement electric production? What criteria would you use to make your recommendation?

I would prefer nuclear power over coal, to supplement electric production. Use of coal has several consequences associated with the environment and public health. It causes lung disorders in people who work in coal mines, is responsible for acid rains, acid rains turns soil unproductive and kills the plant vegetation of an area. Burning of coal releases carbon dioxide into the atmosphere which is responsible for global warming. Nuclear power is relatively cheap, does not cause environmental pollution, there's no poisonous gas emissions or problems associated with global warming. However, the biggest problem with nuclear power is the discharge of radioactive waste. Since stringent regulations are imposed regarding disposing of nuclear waste, I believe it's generally safer than coal.

2 types of unpopular reactors

May become popular in the future 1. Gas-cooled reactors 2. Nuclear breeder reactors

Nuclear reactor: Moderators

Moderators are used to slow down the fast-moving neutrons so that they are more effective in splitting other U-235 nuclei and maintaining a chain reaction. The most commonly used moderators are water and graphite

Issues Related to the Use of Nuclear Fuels

Most of the concerns about the use of nuclear fuels relate to the danger associated with the radiation produced by the fuel and the waste products of its use. 1. Biological Effects of Ionizing Radiation 2. Radiation Protection 3. Reactor Safety 4. Terrorism 5. Nuclear Waste Disposal 6. Decommissioning Nuclear Power Plants

What environmental advantage does natural gas have over oil and coal?

Natural gas releases less carbon dioxide than oil as well as less air pollutants

Natural Gas Use

Natural gas, the third major source of fossil-fuel energy, supplies about 25 percent of the world's energy.

Describe the processes that resulted in the formation of oil and natural gas.

Oil and natural gas are formed from marine organisms that accumulate in the ocean floor and are buried in sediment. These organisms break down the released oil into the sediment which depending on the type of sediment traps the oil

What is the most common environmental problem associated with the extraction and transportation of oil?

Oil spills are the most common problem associated with oil extraction

How does radiation cause damage to organisms?

Radiation damages the DNA and other molecules of cells

What are the products of the nuclear disintegration of a radioactive isotope?

Radiation is the product of the disintegration of a radioactive isotope

What are secondary and tertiary oil recovery methods? Why is their use related to the price of oil?

Secondary recovery methods include pumping water or gas into the well to drive the oil out of the pores in the rock.These techniques typically result in up to 40 percent of the oil being extracted.Tertiary recovery methods include pumping steam into the well to lower the viscosity of the oil and allow it to flow more readily.These methods are expensive and will be used if extraction is profitable. This is why the price of oil is high

What happens during Stage 1 of the decommissioning of a nuclear power plant?

Stage 1 involves removing fuel rods and water used in the reactor and properly storing or disposing of them. This removes 99 percent of the radioactivity. The radioactive material remaining consists of contaminants and activated materials. Activated materials are atoms that have been converted to radioactive isotopes as a result of exposure to radiation during the time the plant was in operation. These materials must be dealt with before the plant can be fully decommissioned

What regions of the world have the largest reserves of coal? Of oil? Of natural gas?

The US and China have the largest reserves of coal. The Middle East and Eurasia has the largest oil reserves and a large portion of the natural gas reserves

Coal-burning electric power plants in the Midwest have contributed to acid rain in the eastern United States. Other energy sources would most likely be costlier than coal, thereby raising electricity rates. Should citizens in eastern states be able to pressure utility companies in the Midwest to change their method of generating electricity? What mechanisms might be available to make these changes? How effective are these mechanisms?

The acid rains that cause damage in the eastern US originate in the coal-burning power generating companies in the Midwest. It naturally upsets the people of the eastern US due to the losses they suffer. Since people cannot directly pressurize companies in the Midwest to shift to an alternate method of electricity generation, it is necessary for the governments intervention. If neglected, this may create differences between people of two regions. The alternate mechanisms available are: - solar energy - wind energy - nuclear energy Solar energy: the regions experiences bright sun only few weeks a year, so this can't be the best option. Wind energy: Though this is cheap and reliable, the Midwest is prone to frightening tornadoes. The wind turbines may not survive the devastating tornadoes. Nuclear energy: This is a cheap and reliable energy source for this region.

Some states allow consumers to choose an electric supplier. Would you choose an alternative to nuclear or coal even if it cost more?

The choice of alternative to nuclear or coal depends on a person's economic status. Coal burning is associated with high levels of pollution and global warming, and nuclear power plants pose the problem of radiation and safe disposal of waste. I would prefer solar power over the 2 alternatives, if I had money to do so. This is renewable energy, pollution is totally absent. Solar energy does not cause any environmental problems.

Nuclear reactor: The coolant

The coolant is needed to manage the large amount of heat produced within the nuclear reactor. The coolant is needed to transfer the heat away from the reactor core to the turbine to produce electricity. In most reactors the core coolant is water, which also serves as the moderator, but gases and liquid metals can also be used as coolants in special kinds of nuclear reactors.

Nuclear reactor: Fuel

The fuel most commonly used in nuclear reactors is uranium-235 (U-235). When the nucleus is split, two to three rapidly moving neutrons are released, along with large amounts of energy that can be harnessed to do work.

What are the major environmental problems associated with the use of nuclear power?

The major environmental problems associated with nuclear power is the disposal of high-level radioactive waste, exposure to radioactivity during mining, processing, and transportation, and threat of accidents

3. Reactor Safety

There are currently 449 operating nuclear power plants and about an additional 150 which have operated in the past but have been shut down. Nearly all nuclear power plants have operated without serious accidents. However, three accidents generated concern about nuclear power plant safety: Three Mile Island in 1979, Chernobyl in 1986, and Fukushima Dai-ichi in 2011.

What options are available during Stage 2 of the decommissioning of a nuclear power plant?

There are three options to this second stage of the decommissioning process. 1. Decontaminate and dismantle the plant as soon as it is shut down. 2. Secure the plant for many years to allow radioactive materials that have a short half-life to disintegrate and then dismantle the plant. (However, this process should be completed within 60 years.) 3. Entomb the contaminated portions of the plant by covering the reactor with reinforced concrete and placing a barrier around the plant.

Unconventional Sources of Oil and Natural Gas

These unconventional sources are more difficult to develop because they will not readily flow either because they consist of mixtures of hydrocarbons with a very high viscosity (thickness) or because the substrate rock has few channels that allow for their movement. Several of these unconventional sources are: tar sands (oil sands), oil shale, and tight oil.

List the three primary methods of protecting people from damaging radiation.

Time, distance, and shielding are the basic principles of radiation protection

Resource

a naturally occurring substance of use to humans that can potentially be extracted. Ex: discussing deposits of nonrenewable resources such as fossil fuels, iron ore, or uranium ore

Alpha radiation

consists of a moving particle composed of two neutrons and two protons. Alpha radiation usually travels through air for less than a meter and can be stopped by a sheet of paper or the outer, nonliving layer of the skin.

Beta radiation

consists of moving electrons released from nuclei. Beta particles travel more rapidly than alpha particles and will travel through air for a couple of meters. They are stopped by a layer of clothing, glass, or aluminum

The Nuclear Fuel Cycle

follows the process from the mining of uranium to the disposal of the waste from power plants. 1. Mining and Milling 2. Enrichment 3. Fuel fabrication 4. Use of the fuel 5. Reprocessing or storage 6. Transportation

Gamma radiation

is a type of electromagnetic radiation that does not consist of particles. Other forms of electromagnetic radiation are X rays, light, and radio waves. Gamma radiation can pass through your body, several centimeters of lead, or nearly a meter of concrete.

Distinguish between reserves and resources.

resource is a naturally occurring substance of use to humans that can potentially be extracted. Reserves are known deposits from which materials can be extracted profitably with existing technology under prevailing economic conditions.

List three environmental impacts of the use of coal.

• Landscape disturbance- Surface mining disrupts the landscape, as the topsoil and overburden are moved to access the coal. • Acid mine drainage- Since coal is a fossil fuel formed from plant remains, it contains sulfur, which was present in the proteins of the original plants. • Air pollution Dust- is generated by mining and transportation of coal. The large amounts of coal dust released into the atmosphere at the loading and unloading sites can cause local air pollution problems

What happened at Chernobyl, Three Mile Island, and Fukushima? Why did it happen?

• The accident at Chernobyl was the result of a nuclear reactor meltdown in association with a test and several safety violations and mistakes. The immediate consequences were 31 deaths, 500 persons hospitalized, and 116,000 people evacuated. Delayed effects include an increase in thyroid cancer in exposed children and fetuses. • Three Mile Island- On March 28, 1979, the main pump that supplied cooling water to the reactor broke down. the accident was caused by a combination of equipment failures, lack of appropriate information to the operator, and decisions by the operator. • Fukushima- On March 11, 2011, a magnitude 9 earthquake 130 km off the northeast coast of Japan triggered the automatic shutdown of several nuclear reactors in the vicinity of the earthquake. The loss of the ability to cool the reactors and their adjacent spent fuel storage sites resulted in explosions and fires that were caused by the release of hydrogen from the overheated reactors and one of the spent fuel storage sites