Nuclear Waste

The creation of huge quantities of long-lived radioactive waste is the most formidable problem facing the nuclear power industry today. The difficulty of waste disposal was not considered to be a big problem during the time when power plants were first introduced; it was assumed that waste could be recycled or buried. Unfortunately, finding safe ways of storing radioactive wastes so that they do not leak radiation into the environment has proved to be a much more difficult task than anticipated.

What is Radioactivity?

Radioactivity occurs when unstable nuclei of atoms decay and emit particles. These particles may have high energy and can have bad effects on living tissue. There are many types of radiation. 

How does nuclear waste get to you?

The planet's water cycle is the main way radiation gets spread about the environment. When radioactive waste mixes with water, it is ferried through this water cycle. Radionuclides in water are absorbed by surrounding vegetation and ingested by local marine and animal life. Radiation can also be in the air and can get deposited on people, plants, animals, and soil. People can inhale or ingest radionuclides in air, drinking water, or food. Depending on the half life of the radiation, it could stay in a person for much longer than a lifetime. The half life is the amount of time it takes for a radioactive material to decay to one half of its original amount. Some materials have half-lives of more than 1,000 years!
Paths of Radiation to the Body

Radioactive wastes come in many different forms including the following:

• protective clothing of people in contact with radioactive materials
• the remains of lab animals used in experiments with radionuclides
• cooling water, used fuel rods, and old tools and parts from nuclear power plants
• mill tailings from uranium-enrichment factories
• old medical radiation equipment from hospitals and clinics
• used smoke detectors which contain radioactive americium-241 sensors

Types of nuclear waste

High-level waste

Nuclear waste is divided into several categories. High-level waste consists mostly of spent nuclear reactor fuel from both commerical power plants and military facilities, as well as reprocessed materials which can emit large amounts of radiation for hundreds of thousands of years. We take an example for U.S. Commercial nuclear power plants in the U.S. produce 3,000 tons of high-level waste each year. The amount of spent fuel removed annually from the approximately 100 reactors in the U.S. would fill a football field to a depth of one foot. When spent fuel is removed from a reactor core, it still emits millions of rems of radiation.  In the absence of high-level waste repositories, nuclear power plants genearlly store their spent fuel rods in lead-lined conceete pools of water. These pools somewhat contain the spread of gamma radiation by keeping the rods relatively cool. They also help prevent fission. The average commercial power plant puts 60 used assemblies into temporary storage each year and will probably continue to do so until the year 2000, when responsibility for spent fuel will be transferred to the Department of Energy. Space is running out at many plants though. The plants have another option of storing their spent fuel at other plants still under construction. It is theoretically possible to reduce the amount of storage space that spent fuel rods require by removing them from their assemblies, bundling them tightly, and then packing them into heavily shielded dry storage, but repacking these highly radioactive rods may present too much of a challenge. For long-term storage of high-level waste, a waterproof, geologically stable repository and leak-proof waste container is required. Packaging has to be tailored to the volume of the waste, the actual radioactive isotopes of elements it contains, how radioactive it is, its isotopes' half-lives, and how much heat it still generates. One technique for packaging high-level wastes involves melting them with glass and pouring the molten material into impermeable containers. The containers could be buried in soil or in a rock pile and surrounded by fill material and a barrier wall. From the 1940s through the 1960s, barrels of radioactive waste were frequently dumped in oceans. This ended in 1970 when the EPA (Energy Protection Agency) determined that at least one-fourth of these barrels were leaking. A new, possibly safer proposal under consideration for long-term ocean storage includes offshore drilling and a procedure known as self-burial. In offshore drilling, holes would be drilled into the seabed and filled with barrels of waste. In self-burial, specially shaped barrels would be dumped and left to sink to the ocean floor. Geologic disposal is currently the most popular solution for waste disposal. During the 1980s, the U.S. government invested more than $2 billion into geologic disposal. In this form of disposal, mined tunnels with deep holes for waste canisters would be built using conventional mining techniques. Monitoring and waste retrieval would be relatively easy. In 1987, a site was chosen for the first permanent high-level commercial nuclear waste storage repository in the United States--Yucca Mountain, 100 miles northwest of Las Vegas, Nevada. Expected to cost up to $15 billion, this repository is scheduled to go into operation by the year 2010. Over the years, a number of other ideas for high-level waste disposal have been proposed and, at least temporarily, abandoned. One was disposal in space, in which sealed containers of radioactive material would be sent up into distant orbits. This would be an expensive and risky operation, as problems on the launchpad or in space could expose the earth and atmostphere to an enormous amount of radiation. Another suggestion was burying waste under the Antarctic ice sheets. However, this would risk irradiating that area and the surrounding sea. A much safer idea, which would render disposal unnecessary, is to bombard radioactive waste with subatomic particles to transform it into less harmful isotopes. Unfortunately, this attractive proposal awaits still unrealized technology.

Mill Tailings

Mill tailings, left over when ore is refined and processed is the largest by volume of any form of radioactive waste. Only 1% of uranium ore contains uranium--the rest is left on-site as sandlike residue. These tailings are generally left outdoors in huge piles, where they blow around, releasing radioactive materials into the surrounding air and water. By 1989, some 140 million tons of mill tailings had accumulated in the United States alone, with 10 to 15 million tons added each year. Although their radiation is generally less concentrated than other types of waste, some of the isotopes in these tailings are long-lived and can be hazardous for many thousands of years. Until their radioactive risk was known, mill tailings were sometimes used as foundation and building materials, especially in western states. When their risk was discovered, these materials in the buildings had to be monitored. These monitored sites are generally safer, although some groundwater contamination still occurs at them. It has been recommended that tailings be stored underground in clay pits, far from population centers.

Low-Level Waste

Low-level wastes are usually defined in terms of what they are not. They are not spent fuel, milling tailings, reprocessed materials, or transuranic materials. Low-level waste includes the remainder of radioactive wastes and materials generated in power plants, such as contaminated reactor water, plus those wastes created in medical laboratories, hospitals, and industry. Wastes in this category usually, although not always, release smaller amounts of radiation for a shorter amount of time. "Low level" does not mean "not dangerous," though. Although its radioactivity is usually less concentrated than that of high-level waste, low-level waste can be dangerous for up to tens of thousands of years. Most low-level wastes come from reactors. These wastes can be divided up into two categories:
• Fuel wastes are fission products that leak out of fuel rods and into cooling water.
• Nonfuel wastes result when stray neutrons bombard anything in the core other than fuel--such as the reactor vessel itself--and cause them to become radioactive.
The remainder of low-level wastes comes from industry and institutional sources, including pharmaceutical plants, universities, and medical facilities. Instead of going to low-level waste dumps, these wastes are often kept on-site for the short time it takes for them to decay to safe levels. Then they are deposited into sanitary landsfills. However, it is likely that liquid wastes are literally poured down the drain, whether or not they are still radioactive. Low-level waste landfills were first built in the 1960s. In near-surface land burial, containers of waste fill a trench and are covered and surrounded by compacted earth.  There are a number of unresolved issues regarding disposal of low-level wastes. The current institution control period (the amount of time a waste site must remain under guard after it has been filled and closed) is only 100 years. Yet the hazards presented by some low-level wastes can continue for thousands of years. What will keep future generations from uncovering and being contaminated by these substances?

So, what about the future?

Currently, better methods are being developed to decrease waste volume and make methods of separating the waste by decay rate more efficient. Development of waste storage is far from complete. There are many alternatives to consider and many techniques to develop and improve upon. There has also been much controversy about site selection and disposal methods. Although urban areas consume most of nuclear-generated electricity, radioactive wastes are dumped in rural settings, where property values decline and public health is jeopardized. Although hazards of radioactive waste are less visible than some other problems associated with nuclear energy, such as reactor accidents and nuclear weapons, they are no less dangerous, and decisions made concerning this waste will be felt far into the future.  Full article Here.  Anything to comment? Thinkquest Forum.

Should Malaysia build a nuclear power plant?

Unlike a coal or gas power plant, a nuclear power plant can be considered green as it emits very little CO2 into the atmosphere. Then again, the same can be said of solar, wind and hydroelectric power plants as these are all not dependant on the use of fossil fuels.

Last year, the former Minister of Energy, Water & Communications mentioned that Malaysia will eventually use nuclear energy. Now that we have a new Minister and a renamed Ministry of Energy, Green Technologies and Water, will we soon see the building of a nuclear power plant?
Before any such plan is unveiled, let's educate ourselves.

A nuclear power plant generates radioactive waste

Power plants that depend on atomic energy don't operate that differently from a typical coal-burning power plant. The key difference between the two plants is the method of heating the water. While older plants burn fossil fuels, nuclear plants depend on the heat that occurs during nuclear fission, when one atom splits into two. When the water is heated, it turns into steam which drives a turbine, which spins a generator to produce power. On average, a nuclear power plant annually generates 20 metric tons of used nuclear fuel, classified as high-level radioactive waste.However, despite the astonishing amount of radioactive waste it generates, modern nuclear power plants are able to manage the waste well. There is danger of the waste leaking and affecting public health only if we were to hire someone like Homer Simpson to manage that.

A nuclear power plant can be used to build nuclear weapons
A nuclear power plant works by enriching uranium. To generate electricity, we will need to enrich uranium by only 2-3 percent. However, if anyone happened to be feeling ambitious and decide to secretly enrich the uranium up to 90 percent, he will be able to build nuclear weapons.Once you operate a nuclear power plant, the international watchdogs will be keeping an eye on you, and it will be almost impossible to secretly enrich uranium by up to 90 percent.

Other options 
Some time ago, we soaked 700sq km of rainforests in deep water to build a hydroelectric dam. After that, we refrained from using the electricity generated because it was discovered that the building of undersea cables to transmit the electricity from Sarawak to Peninsular Malaysia would be too high. We could still build the undersea cables.

So what do you think? Should Malaysia build a nuclear power plant?

Critics question need for Malaysia's nuclear power plan

Malaysia's plan to build its first nuclear power plant ran into opposition Wednesday from politicians and environmentalists who queried how necessary and safe it would be. The government on Tuesday said the country's growing energy needs would be met by a nuclear power station that would be up and running in 2021. But Lim Guan Eng, secretary general of the opposition Democratic Action Party said Malaysia already had enough capacity. "Clearly Malaysia has more energy than it needs. Without any economic grounds or energy security justification, why then does Malaysia need a nuclear power plant?" he asked. "Malaysians wonder what assurances can be given in relation to safety and environment following the 1986 Chernobyl nuclear plant accident in Ukraine that claimed 56 lives and resulted in 4,000 cancer deaths," he added. Loh Chi Leong, executive director of the Malaysian Nature Society told AFP: "There are obvious concerns over nuclear power." Malaysia must develop energy efficiency technology and invest in solar, hydro and wind power, he said. Peter Chin, minister for energy, green technology and water, said Tuesday the nuclear option was the solution to Malaysia's energy needs, and indicated the government was not keen to debate with critics but would work to reassure those living near the eventual site. Loh said: "We would appreciate much more debate on this issue. We want an integrated formal power plan. We should concentrate on renewable energy." Mohideen Abdul Kader, advisor with the environmental group Friends of the Earth Malaysia, expressed anger at the announcement. "We are angry that the government does not want to engage with stakeholders. It is shocking news. Under ex-prime minister Mahathir Mohamad, the government said it was not going nuclear. There is a U-turn in our policy," he said. Mohideen said his group also opposed the plan because Malaysia could obtain technology to make nuclear weapons. Malaysia last month said it would strictly enforce a new law to curb trafficking of nuclear weapon components after being linked to the illegal supply of sensitive technology to Iran and Libya. "There will be political repercussions if the government persists on building a nuclear power plant," Mohideen warned, adding that the country should concentrate on energy conservation. State energy firm Tenaga has said it could construct the country's first 1,000 megawatt nuclear power plant at a cost of 3.1 billion dollars. The government had asked it to look at the option as oil prices surged and in view of the country's limited supply of oil and natural gas.

Malaysia ahead with nuclear plans learn from Japan crisis

The No. 3 nuclear reactor of the Fukushima Daiichi nuclear plant is seen burning after a blast yesterday, March 14, 2011. Muhyiddin said the Malaysian government will learn from Japan to ensure public safety.

PUTRAJAYA, March 15 — Malaysia is taking note of the Japan nuclear crisis when implementing its plan to build two nuclear power plants in the future, Deputy Prime Minister Tan Sri Muhyiddin Yassin said today. He hat while the government is concerned about public safety and is watching developments in Japan, he remained confident that Malaysia would “implement what is the best” for the country.The deputy prime minister stressed that the government would learn from Japan to ensure public safety.“I think it is something which every country in the world is taking note of, what is happening in Japan. There are many things that we can learn but what is important is the safety of the country and the people.“In this matter, we have an agency that is responsible and they know what they are doing and we are confident that they will implement what is the best,” he told reporters during a press conference today.Energy, Green Technology and Water Minister Datuk Peter Chin had also said that the “government will not do it secretly without informing the public”.Chin added that the Malaysia Nuclear Power Corporation had opened a tender to international consultants to conduct a study on the location, suitability and safety of the location, type of technology and public acceptance of the proposal.However, MCA president Datuk Seri Dr Chua Soi Lek yesterday had called on the government to reconsider building a nuclear plant following the explosions to nuclear reactors in Japan after the March 11 earthquake and tsunami that devastated the country.He said the government must re-evaluate nuclear power in the country.Reuters reported today that Japan’s Prime Minister Naota Kan has warned that radioactive level in the vicinity of the Fukushima Daiichi plant had become high and that the risk of more radioactive leakage was increasing.

NIGHTMARE OF JAPAN!

On date 11 Mac 2011, the dark day for Japanese. The most powerful earthquake recorded in Japanese history, magnitude until 8.9. This Tohoku earthquake triggered extremely destructive waves up to 38.9 meters that struck Japan. The tremors were the result of a violent uplift of the sea floor 80 miles off the coast of Sendai, where the Pacific tectonic plate slides beneath the plate Japan sits on. Tens of miles of crust ruptured along the trench where the tectonic plates meet. The earthquake occurred at the relatively shallow depth of 15 miles, meaning much of its energy was released at the seafloor. Regular aftershocks have already hit Japan as the Earth's crust continues to rupture along the Japan Trench. Those tremors are expected to be weaker and are less likely to produce another tsunami.

On March 12th, the government ordered evacuation within a 20-km radius around the nuclear power plant. Most residents had already left by then; however, approximately 1,500 patients remained in hospitals or nursing facilities. In the early morning of the 14th, these patients were transported to the SOSO Healthcare Center a screening point located 24 km north of the damaged power plant by buses, police vehicles and Japan Self Defense Forces transport. However, the limited capacity of the hospitals in Fukushima caused difficulty in reallocating these patients to the appropriate facilities. Many patientshad to wait for more than 24 hours, in the transport vehicles, in the cold weather without water or food. Unfortunately, at least 21 elderly patients died from hypothermia or dehydration.

As the situation in the 20-30-km zone around the plant deteriorated, the government instructed on March 15th that residents in this zone should remain indoors. However, there was still great confusion and fear of the effects of radiation, causing vital supplies such as food, water and gasoline as well as medical supplies to not be received in most of the area. The shortage of supplies had severe impacts on the hospitals and care facilities where approximately 1,700 patients remained. The local government eventually decided to move all of the patients out of the zone, which was completed by the evening of March 20th.

Initially, a value of 13,000 counts per minute, as measured by a Geiger-Müller counter, was used to indicate the need for evacuee decontamination. However, because of the disrupted water supply, very low temperature, and the need to cope with thousands of evacuees, this was increased to 100,000 counts per minute. At least 13 screening points were established by the night of March 14th, and more than 20,000 people had been screened by the 16th.Although a radiation emergency medical system had been developed, few had expected the magnitude of the damage to the nuclear power plant. Doctors and health care specialists voluntarily gathered in Fukushima to set up a radiation emergency medical management panel, which coordinated activities. Although these efforts were started with minimum resources, they were at the core of the subsequent medical responses dealing with the most difficult situation in Fukushima.

The first Japan’s nuclear Fukushima totally corrupted and destroyed. Death toll increased very fast, of which most serious ongoing INES-level 7 event. There more hazards from the nuclear power plant, under normal conditions, it can effect by radiation. The radiation release is very low, but potential risk of radioactive materials as that released by the Hiroshima atomic bomb. Discount the recent accident in Fukushima caused by earthquake and tsunami, two major historical serious accidents were triggered by two equipment malfunction and human errors.

posting test:


nuclear test 1

(tuesday, 12th July 2011) 90min

Q1 - energy mix & NPP component

Q2 - atomic & nuclear physics

Q3 - reactor theory 1