A. In a conventional nuclear reactor, isotopes of uranium and plutonium undergo controlled nuclear fission, and the resulting heat is used to produce steam that spins turbines to generate electricity.
1. A controlled chain reaction occurs when nuclei of atoms are split. The heat from the reactions is used to produce high-pressure steam that spins turbines that generate electricity.
2. Light-water reactors (LWRs) produce about 85% of the world’s nuclear-generated electricity (diagram of how reactor works).
3. Long, thin rods are packed with fuel pellets, and each pellet contains energy equivalent to 1 ton of coal or 4 barrels of crude oil.
4. Control rods absorb neutron-absorbing materials and move in and out of spaces between the fuel assemblies in the core. This regulates the rate of fission and amount of power the reactor produces.
5. A moderator (material that slows down neutrons) keeps the reaction going. It may be water, graphite, or deuterium.
6. A coolant, usually water, circulates through the core to remove heat to keep the components from melting and to produce steam for generating electricity.
7. A containment vessel with thick, strong walls surrounds the reactor as a safety backup. These are usually made of 4-foot reinforced concrete with a steel liner.
8. Spent rods are stored on-site in water-filled pools or dry casks with thick steel walls. These rods must be stored safely for 10,000–20,000 years until radioactivity levels are safe.
9. All the safety features make nuclear power plants very expensive to build and maintain.
B. The nuclear fuel cycle includes the mining of uranium, processing it to make a satisfactory fuel, using it in the reactor, storing highly radioactive wastes safely, and dealing with the reactor after its useful life.
1. A nuclear power plant must be decommissioned after 15–60 years of operation. It contains large quantities of radioactivity that must be kept out of the environment.
2. A closed nuclear fuel cycle removes fissionable isotopes uranium-235 and plutonium-239 for reuse as nuclear fuel. This is rarely done currently because of high costs and potential use of the materials in nuclear weapons.
3. In an open nuclear fuel cycle, the isotopes are eventually buried in an underground disposal facility. These wastes must be stored for about 240,000 years.
C. Nuclear power has not lived up to its promise.
1. Nuclear power plants began being developed in the late 1950s for three reasons.
a. The Atomic Energy Commission promised utility executives that fuel would be produced at much lower costs than coal, etc.
b. The government paid about one-fourth of the cost of building the first reactors with a guarantee of no cost overruns.
c. Congress passed the Price-Anderson Act to protect the U.S. nuclear industry and utilities from significant liability in case of accidents.
2. The goals set forth in the fifties have not been met even with an investment of $2 trillion worldwide.
3. Electricity production from nuclear power plants is the slowest growing energy source.
4. The U.S. has not ordered any new reactor since 1978; all 120 plants ordered since 1973 have been cancelled (US nuclear plant locations).
5. Several major reasons for the failure of nuclear power to grow are multibillion-dollar cost overruns, higher operating costs, more malfunctions than expected, and poor management.
6. Public concerns about safety and stricter government regulations are two major setbacks.
7. Investors are concerned about the economic feasibility of nuclear power.
8. Vulnerability of these plants to terrorist attacks is another concern.
D. The advantages of conventional nuclear fuel are: fairly low environmental impact and low risk of accident; however, costs are high, storing wastes is difficult and costly, and facilities are vulnerable to terrorist attack. (Advantages and disadvantages of using nuclear power to produce electricity)
1. Increased use of nuclear fuel plants would not significantly reduce dependence on oil, since oil use is primarily for gasoline and diesel fuel for transportation.
2. The U.S. Nuclear Regulatory Commission (NRC) estimates that there is a 15–45% chance of a complete core meltdown at a U.S. reactor during the next 20 years. Also, 39 U.S. reactors have an 80% chance of failure in the containment shell from a meltdown or explosion of gases inside containment structures.
3. There is widespread distrust of the ability of the NRC to enforce nuclear safety in nuclear facilities.
E. There is great concern about the vulnerability of U.S. nuclear power plants and the nuclear wastes they store to terrorist attack.
1. The 2002 study by the Nuclear Control Institute found that the plants were not designed to withstand the crash of a large jet.
2. Insufficient security at nuclear plants is another concern. The same study also found that many security guards at nuclear power plants have low morale and are overworked, underpaid, under trained, and not equipped to repel a serious ground attack by terrorists.
F. Spent fuel rods stored outside of the containment shells at nuclear plants are vulnerable to attack.
1. The storage pool generally holds 5–10 times more than the core inside a plant’s reactor.
2. If the radioactive material were exposed to air and steam, it would cause the outer cover to catch fire and burn fiercely. The fire could not be put out and would release significant amounts of radioactive materials into the atmosphere and contaminate large areas for decades.
3. Studies indicate that about 161 million people live within 75 miles of an aboveground spent-fuel site.
4. Nuclear power officials feel that plants are save from attack, while critics call for constructing much more secure structures to protect spent-fuel storage sites.
G. Low-level radioactive waste must be stored safely for 100–500 years.
1. Low-level radioactive wastes give off small amounts of ionizing radiation.
2. These wastes include tools, building materials, clothing, glassware, and other materials that have been contaminated.
3. From the 1940s to 1970, most low-level radioactive waste was put in steel drums and dumped into the ocean.
4. Today in the U.S., low-level wastes are placed in drums and shipped to the two regional landfills run by federal and state governments.
5. To lower costs, nuclear industry and utility officials are lobbying Congress and the NRC to let these wastes be mixed with ordinary trash and deposited in landfills.
H. Scientists cannot agree on whether there is a safe method to store high-level radioactive waste.
1. Some of the proposed methods are:
b. Shoot it into space or into the sun. This strategy has been abandoned for now.
c. Bury it under the Antarctic ice sheet or the Greenland ice cap. This strategy is prohibited by international law. There is the possibility of heat making the ice sheets unstable.
d. Dump it into descending subduction zones in the deep ocean. Wastes might be spewed out by volcanic activity. This method is also prohibited by international law.
e. Bury it in thick deposits of mud on the deep-ocean floor in areas that tests show have been geologically stable for 65 million years. Because of corrosion problems this method is also prohibited by international law.
f. Change it into harmless, or less harmful, isotopes. There is no way to do this at present.
I. There is disagreement over the decision to store high-level nuclear wastes at an underground storage site in Nevada (map of highways leading from nuclear plants to Yucca Mountain).
1. This facility is expected to cost $58 billion to build and is scheduled to open in 2010.
2. After it is filled, the facilities will be monitored for 300 years, and then sealed.
3. The Yucca Mountain site is located in an area that currently receives only 15 centimeters of rain per year.
4. There is concern that rock fractures and tiny cracks may allow water to leak into the site and corrode the containers, releasing radioactive material. This material could explode.
5. The Yucca Mountain site has a nearby active volcano, and 32 active earthquake faults running through the site.
6. In January 2002, the U.S. energy secretary stated that the site was scientifically sound despite the concerns of scientists.
7. The shipment of radioactive materials across the country makes them vulnerable to terrorist attack.
8. The U.S. National Academy of Sciences, in 2002, urged the U.S. government to slow down and rethink the nuclear waste storage process.
9. Nevada is still fighting the project in the courts.
J. A nuclear power plant must be decommissioned when it reaches the end of its useful life.
1. Scientists have proposed three ways to decommission plants.
a. Dismantle the plant, and store its large volume of radioactive materials in a high-level waste storage facility.
b. Put up a physical barrier around the plant, and set up full-time security for 30–100 years before the plant is dismantled.
c. Enclose the entire plant in a tomb that must last and be monitored for several thousand years.
2. Decommissioning adds to the total costs of nuclear power as an energy option.
3. Congressional auditors reported that the owners of the nuclear power reactors are not setting aside enough money to decommission plants. Taxpayers will be saddled with the bill.
K. Dirty radioactive bombs are made of explosives and mixed with radioactive material.
1. Small amounts of radioactive material may be stolen from hospitals, university laboratories, and some industries that use small amounts of radioisotopes.
2. A dirty bomb could kill 12–1,000 people and increase cancers.
3. Cleaning up such an area would cost billions of dollars.
L. Nuclear power is an expensive way to produce electricity, even with government subsidies.
1. Articles in Forbes and the Economist stated that not a single nuclear power plant in the world made commercial sense.
2. Although the operating costs of many U.S. nuclear power plants have dropped in recent years, the cost of the whole nuclear fuel cycle must be considered in the true cost of nuclear power.
3. Second generation, smaller, advanced light-water reactors are supposed to have built-in passive safety features that make explosions/radioactive emissions almost impossible.
4. Nucleonics Week states that experts are unconvinced that the goals have been achieved, and it still does not eliminate the threats and hazards of long-term storage of wastes.
5. Each new plant will cost up to $2 billion.
M. Nuclear breeder reactors have been very costly, with bad safety records, and the technology has essentially been abandoned.
1. Breeder nuclear fission reactors generate more nuclear fuel than they consume. This means that the world’s known uranium reserves would last at least 1,000 years.
2. The reactor uses liquid sodium coolant that ignites when exposed to air and is explosive if it contacts water.
3. The U.S. ended government-supported research for breeder technology in 1994.
4. The French built a commercial-size breeder reactor in 1986. It cost so much that it was shut down in 1998 permanently.
N. Nuclear fusion has a number of advantages, but after 50 years, this technology is still at a laboratory stage.
1. This type of energy production has a number of advantages such as no emissions of conventional air pollutants or carbon dioxide. The wastes are much less radioactive so would only need to be stored for about 100 years.
2. There would be no risk of a meltdown or risk from terrorist attack.
3. Fusion power could be used to destroy toxic wastes, supply energy, and decompose water and produce hydrogen gas to run a hydrogen economy by the end of this century.
4. Building a fusion reactor would be much more expensive than the cost of a conventional reactor.
O. There is disagreement over whether the U.S. should phase out nuclear power or keep this option open.
1. Some analysts feel that nuclear power should be phased out regarding all or most government subsidies and the money used to subsidize and accelerate the development of other promising energy technologies.
2. According to investors and the World Bank analysts, conventional nuclear power simply cannot compete in today’s energy market.
3. Proponents of nuclear power feel that governments should continue funding research and development. They say that we need to keep nuclear options open if various renewable energy options fail to keep up with electricity demands and reduce CO2 emissions to acceptable levels.