Nuclear Energy

Managing nuclear waste

2008-11-17T09:16:00.005+07:00

There are three different classifications of radioactive waste: low, intermediate and high.

Low level waste emits low radiation levels and does not need much shielding, it includes items that have become contaminated with radioactive material or have become radioactive through exposure to neutron radiation. This waste typically consists of contaminated protective shoe covers and clothing, wiping rags, mops, filters, equipments and tools, medical tubes, swabs, injection needles and syringes.

Intermediate and high level waste require more shielding and safety processes to handle. Intermediate Level Solid Waste (ILSW) is generated chiefly from radiopharmaceutical production, and reactor operations. The spent fuel from ANSTO's research reactor is classified as intermediate-level waste. It is generally short-lived, but usually needs to be shielded. Intermediate-level waste can be solidified and put into a waste repository. Radioactivity gradually diminishes as radioactive elements decay into more stable elements, so waste gradually becomes less radioactive and safer to handle over time.

Most of Australia's current production of radioactive waste comes from ANSTO. Other sources include radioactive materials produced for medical, research and industrial applications. >There are relatively large amounts of waste in storage which arose from 'non-nuclear' activities, such as CSIRO research or the use of radium in luminous dials. See Amounts of Radioactive Waste in Australia.

Radioactive waste is handled according to its classification. Most of the solid radioactive waste produced by ANSTO is low-level waste. ANSTO produces some intermediate-level wastes, mainly from the production of molybdenum for nuclear medicine treatments. A small amount of intermediate-level waste will also arise from the reprocessing of ANSTO's spent nuclear fuel and both low and intermediate level waste will result from the decommissioning of the HIFAR research reactor over the next decade. Australia does not produce any high level waste.

What does Australia currently do with its radioactive waste?

The management of radioactive waste is governed by rigorous national and international standards. At ANSTO, low-level solid waste is segregated for long-term storage in earthquake-proof facilities. Low-level wastewater is collected, analysed and treated to reduce its radioactivity to internationally acceptable levels. The treated water is then discharged to sewer in accordance with a trade waste agreement with Sydney Water. Airborne discharges are trapped and treated. Intermediate solid waste is securely stored below ground in purpose-built facilities. Liquid waste is stored in shielded tanks before being processed into solid form for long-term storage.

Spent fuel from the HIFAR and OPAL nuclear research reactors at Lucas Heights is securely stored for several years before being sent overseas for processing or storage. The intermediate level waste resulting from reprocessing of HIFAR's fuel in France and Scotland, will be sent to Australia and stored in the proposed national radioactive waste facility. OPAL spent fuel will be sent to the USA for storage where it will remain. The USA does not reprocess fuel. Currently waste from other medical and industrial facilities are dealt with by the responsible state or territory government.

What do other countries do with their radioactive waste?

Other countries handle low-level and intermediate radioactive waste in much the same way as Australia does. Low-level waste is usually kept in near-surface storage, while intermediate waste is stored in purpose-built above-ground facilities.

Spent nuclear fuel rods are typically put into long-term storage in purpose-built ponds at reactor sites until activity has fallen off enough for reprocessing. This is where any remaining uranium or plutonium is separated and re-used as fuel, as part of a closed cycle. The remaining material can be safely and permanently immobilised using methods such as vitrification or synroc (synthetic rock).

How much radioactive waste does a nuclear power plant produce?

In countries with nuclear power, radioactive waste make up less than one per cent of total industrial toxic wastes.

A nuclear power plant generating 500 megawatts of electricity produces around 20 tonnes of toxic waste a year, and this figure is falling as nuclear reactors become more efficient. Treatment of nuclear waste can reduce the volume substantially. In comparison, a 500-megawatt coal-fired power station produces almost 320,000 tonnes of toxic waste each year, including 2.6 tonnes of uranium and 6.4 tonnes of radioactive thorium.

Future for waste management

Some countries are developing deep geological repositories for secure long-term storage of intermediate and high-level wastes. Finland, Sweden and the US have begun a site selection process.

Researchers are also developing high-temperature methods for reducing the volume of radioactive waste and 'partitioning and transmutation processes' for transforming the most active and long-lived components of radioactive waste into less hazardous materials.

Nuclear Waste Disposal

2008-11-17T09:14:00.002+07:00

As we near the end of the century, the disposal of nuclear waste is becoming a concern. Many nuclear power plants around the world are nearing the end of their operating lives. This is particularly true in the United States where most nuclear power plants are approaching the end of the operational time period allowed in their licenses. Locally the Ginna power plant, 20 miles northeast of Rochester, on Lake Ontario, is attempting to deal with these issues. The close of the cold war has left us with radioactive waste from decommissioned nuclear missiles.

The disposal of radioactive waste from nuclear power plants and nuclear missiles is as politically intense an issue as the plants and missiles themselves. Yet the three issues have remained curiously separate in spite of their close physical ties. Few debates on nuclear power or nuclear weapons discuss the problems of waste disposal should the power plant or missile be decommissioned. >Few debates on nuclear waste disposal discuss the opportunities to close nuclear power plants or get rid of nuclear weapons a disposal site would afford.

Nuclear waste can be generally classified a either "low level" radioactive waste or "high level" radioactive waste. Low level nuclear waste usually includes material used to handle the highly radioactive parts of nuclear reactors (i.e. cooling water pipes and radiation suits) and waste from medical procedures involving radioactive treatments or x-rays. Low level waste is comparatively easy to dispose of. The level of radioactivity and the half life of the radioactive isotopes in low level waste is relatively small. Storing the waste for a period of 10 to 50 years will allow most of the radioactive isotopes in low level waste to decay, at which point the waste can be disposed of as normal refuse.

High level radioactive waste is generally material from the core of the nuclear reactor or nuclear weapon. This waste includes uranium, plutonium, and other highly radioactive elements made during fission. Most of the radioactive isotopes in high level waste emit large amounts of radiation and have extremely long half-lives (some longer than 100,000 years) creating long time periods before the waste will settle to safe levels of radioactivity. This area will describe some of the methods being under consideration, for dealing with this, high level, waste. These include short term storage , long term storage, and transmutation.

source : http://www.history.rochester.edu/class/EZRA/

The Drawbacks to using Nuclear Energy

2008-10-31T00:52:00.001+07:00

Despite the fact that nuclear energy offers great benefits as an alternative source of electric power, nuclear energy as a whole, is still a controversial issue in many countries. The reasons for this center round the issues of safety, waste, and nuclear weapons.

Nuclear Safety

National and international anxiety about nuclear power stems directly from a fear of release of radioactive material and its consequences on people and the environment. The problem, however, is that there is a huge information gap between specialists on the exposures from nuclear power and the public. When one looks at the 1991 report by the United Nations Scientific Committee on the Effects of Atomic Radiation, (UNSCEAR) one would see that the routine generation of nuclear electricity releases only negligible amounts of radioactive materials to the environment.
"The average dose any individual in the world receives each year from all of the activities in the peaceful nuclear fuel cycle is less than 0.1 percent of the inevitable exposures he or she receives from natural radiation sources, such as cosmic rays and radon emitting building materials" ( Trudeau 59).

One has to accept that electricity production can't be totally free of risk. The accident at Chernobyl, in the former USSR, was undoubtedly the most severe radioactive accident the world has experienced since the arrival of nuclear energy as an alternative source of electric power. Although there 31 deaths can be attributed to the Chernobyl accident, there are many misgivings about the true nature of the accident. For example, the people who died, including the nuclear operators and the figherfighters, received very high doses, unlike the surrounding areas that were relatively safe from exposure to high radiation levels. "Contrary to some erroneous reports, no accurate health effects from the incident have been found in the population in the Ukraine and Byelorussia. Elsewhere in Europe, countermeasures taken in many countries immediately after the accident effectively reduced the levels of exposure to the public" (Trudeau 159). One can also see from UNSCEAR data that outside of the Soviet Union, the Chernobyl accident has emitted a dose that is a fraction of what the population receives every year from natural radiation found.

One positive result from the tragic Chernobyl accident is that there is now increased awareness and commitment of the nuclear community to international cooperation in the field of safety. "Through the efforts of utilities and governments, of the IAEA and others, an international nuclear safety regime is emerging, which includes a wide range of arrangements for improving operational safety and emergency preparedness and response to accidents" (Trudeau 159).

The United States has also had a serious accident concerning the production of nuclear energy. "An accident with potential for a core meltdown occurred in the PWR at the Three Mile Island Nuclear Station Unit 2 near Harrisburg, Pennsylvania, on March 28, 1979" ( Glasstone 105). The three Mile Island accident appears to have resulted from a combination of design deficiencies, inadequate procedures, and operator errors. "The consequences will be far reaching" (Glasstone). Like the Chernobyl accident, some good has come from the accident at Three Mile Island. After the accident, the Electric Power Research Institute established a Nuclear Safety Analysis Center to review and analyze information relative to the safety of nuclear power plants. The fact of the matter is that nuclear power plants are safer today than ever before, and they will be unquestionably safer tomorrow than today.

Nuclear Waste

Another drawback that is often associated with the use of nuclear energy is that of nuclear waste. There is a huge misunderstanding that the waste created by nuclear energy is more "dangerous" than that of other means of producing electricity. The truth of the matter is that radioactive waste from nuclear energy may be dangerous for thousands of years, while wastes resulting from the burning of coal, remains dangerous forever. The reason for this is because the toxicity of these stable elements does not decrease over time as does the toxicity of radioactive materials.

Other interesting facts concerning nuclear waste include the reduction in emissions of SO2 and NOx in countries using nuclear power is revealing. "In France, for example, during the period from 1980 to 1986, SO2 and NOX emissions in the electric power sector were reduced by 71 percent and 60 percent, respectively, making a major contribution to reductions of 56 percent and 9 percent, respectively, in total SO2 and NOX emissions in France" (Trudeou p.160). These tremendous reductions were made possible by a fourfold increase in nuclear electricity generation.

Nuclear Weapons

A major drawback to the peaceful use of civilian nuclear power for the production of electricity is that it has allowed for the production of nuclear weapons. While there is no question that nuclear energy has various benefits, the fact that nations can create nuclear weapons of mass destruction t is particularly disturbing. Atomic weapons are created through the splitting of the atom and detonated through the process of fission, while hydrogen bombs are detonated through the process of fusion. Hydrogen bombs are 1000 times more explosive than atomic bombs, thus nations with hydrogen bomb technology can destroy nations within minutes. This thought has led to intense debate over the issue of nuclear energy as an alternative source for energy.

Conclusion

Overall, nuclear energy has proven to be most beneficial to our society. As a result of this technology, the United States has decreased its dependency on foreign-imported oil. In fact, the United States saves about 12 billion dollars each year through the lack of oil it imports from other nations. Nuclear energy has also proven to be a protector of the environment because of the lack of CO2, greenhouse gasses, and other gases it emits into the atmosphere. There are, however, some major drawbacks to using nuclear energy. These drawbacks include the actual safety of using nuclear energy, the waste it produces, and the atomic weapons that nuclear energy promotes. Overall, however, we believe that the use of nuclear energy greatly outweighs any other source of energy.

The Benefits of Using Nuclear Energy

2008-10-31T00:51:00.002+07:00

Powering Our Economy:

Since the oil embargo of 1973, Americans have used energy more wisely and more efficiently. During this time, our population has grown from 211 million to almost 280 million, our economy has grown about 50 percent, but our use of energy has grown only 10 percent. But our economic growth, however, has been fueled largely by electric power.

Between 1973 and 1990, our GDP, which is the measurement of a nation's wealth, grew by about 50 percent. In the same period, electricity use grew by 58 percent. From this information, we can conclude that in order to meet the needs of our strong economy and our growing population, we must have reliable supplies of electric power. The nation's nuclear power plants produced 674 billion kilowatt-hours of electricity in 1996. This was more electricity than the entire country consumed in the early 1950s. Worldwide, there are 442 nuclear power plants at work, contributing about 19 percent of the world's electricity supply.




Reduction of Dependence on Oil:

At the time of the 1973 oil embargo, oil accounted for about 17 percent of US. electric supply; nuclear energy was about 5 percent. In 1990, however, oil represented only about 4 percent of U.S. electric supply, while nuclear energy accounted for about 21 percent. Consequently, the U.S. imports 20 million barrels less of oil each year. For example, since l973, nuclear energy has displaced 4.3 billion barrels of imported oil and reduced our trade deficit by $12 billion. This decrease in our trade deficit causes a direct increase of our Gross National Product, which is also measure of a nations wealth.

Protecting Our Environment:

Nuclear energy plants produce electricity through the fission of uranium, not the burning of fuels. Consequently, nuclear power plants do not pollute the air with nitrogen oxides, sulfur oxides, dust or greenhouse gases like carbon dioxide.

America's nuclear energy plants reduce electric utility emissions of greenhouse gases by 20 percent, or 128 trillion tons per year. Without our nuclear power plants, electric utility emissions of nitrogen oxides would be 2 million tons per year higher. Emissions of sulfur dioxide would be 5 million tons a year higher. Thus, nuclear energy has drastically cut our dependence on foreign imported oil.

In France for example, from 1980 to 1986, SO2 and NOX emissions in the electric power sector were reduced by 71% and 60% respectively, causing reductions of 56% and 9% respectively, in total SO2 and NOX emissions in France (Trudeau 160).

Nuclear energy also offers an alleviation of the global carbon dioxide (CO2) problem that the world can do without. About 1,600 million tons of CO2 annual emissions would have resulted if 16 percent of the world's electricity now generated by nuclear power were to have been generated using coal. This is a significant amount. In fact, it is 8 percent of CO2 now emitted annually from the burning of fossil fuels.

Another important benefit that nuclear generated energy has on our environment is that the wastes produced are completely isolated from the environment. Would we have produced the electricity with coal instead of nuclear energy, at least 90,000 tons of toxic heavy metals would have been released, in addition to tremendous amounts of CO2, SO2, and NOx. Some of these toxic heavy metals include arsenic, cadmium, lead, and mercury. Although the radioactive wastes produced by nuclear energy may be dangerous for thousands of years, part of the waste caused by the burning of coal remains dangerous forever.

The environmental benefits of nuclear energy can he seen clearly in France. In the 1980s, because of concerns over imported oil, France more than tripled its nuclear energy production. During that same period, total pollution from the French electric power system dropped by 80-90 percent.

Worldwide Benefits:

More than 400 nuclear power plants are operating in 25 countries around the world today, supplying almost 17 percent of the world's electricity. In most countries, nuclear energy plays an even larger role as a source of electricity than in the United States. Many of these nations are building new nuclear energy plants to meet the needs of their growing populations and expanding economies. About 83 new nuclear energy plants are currently being built around the world.
  source :http://www.umich.edu/

Experts explode Ziggy's nuclear power theory

2008-10-31T00:49:00.000+07:00

A PANEL of eminent scientists has contradicted one of the central findings of the recent nuclear review commissioned by John Howard, declaring it unrealistic that Australia could have nuclear power plants within 10 years.

A "peer review" panel of experts from Australia and overseas, led by the chief scientist Jim Peacock, has challenged several assertions made by the inquiry headed by former Telstra chief Ziggy Switkowski.

The experts urge the Switkowski taskforce to do more to sell the positive greenhouse benefits of nuclear energy by pointing out that Australia does not need nuclear power to tackle climate change. "The report needs to make clear the reasons why Australia should be considering the nuclear option," the peer review says.

The review team also concludes that the Switkowski report "under-estimates the challenge that will confront Australia if it should choose to expand the scope of its nuclear activities".

The wide-ranging critique is the result of a process where scientific experts, led by Dr Peacock, were asked to examine the Switkowski report and provide feedback to the panel.

Dr Switkowski's draft review, unveiled a month ago, argued that Australia could add nuclear energy to the mix to help reduce carbon dioxide emissions if the Government was prepared to impose a price on pollution. Dr Switkowski said Australia could build a nuclear power plant within 10 to 15 years.

The peer review was initially expected to remain confidential. But Dr Switkowski's panel has taken the decision to release the report before handing their final document to John Howard later this month.

The review team included Dr Peacock, the chairman of the Future Fund and former Commonwealth Bank boss David Murray, and a group of experts from Australia, the United Kingdom and the United States.

Their five-page report raises a number of important issues for the taskforce to consider. These include the unrealistic time frames proposed for building nuclear plants and an "under-estimate" of the amount of workers needed to be trained to work in the industry.

The peer review also says the public must better understand the risks of global warming to understand the connection between the two areas. "Expansion of nuclear fuel cycle activities need not be part of a response to climate change," they say.

Environment group Greenpeace said the review had "torpedoed" the Switkowski report. "The review vindicates Greenpeace's position that nuclear power is too slow, too expensive and too dangerous to be any solution to climate change," Greenpeace spokesman Steve Campbell said.
source :http://www.theage.com.au/