Date sent: Tue, 23 Apr 1996 14:21:14 +1100 Nuclear waste disposal is the way of transporting nuclear high-level waste and fuel rods from a nuclear power production facility and safely isolating them from the environment as much as possible. Many theories abound as how to achieve this; yet as of today, there is no permanent storage facility in the United States licensed to take in this dangerous byproduct-- even after 50 years of power production through nuclear fission. The first nuclear waste was produced by the military during the Manhattan Project in the 1940's. The military undertook this project to produce the first nuclear weapons for use during World War Two. During the beginning of the Cold War, the military continued to produce and stockpile nuclear weapons, creating a huge amount of radioactive waste. By 1957, the first commercial nuclear reactor for electricity production was finished. Finally, in 1982, under strong nuclear industry and public pressures, the US Congress passed a comprehensive group of laws. These laws were collectively known as the Nuclear Waste Policy Act of 1982 [as amended], or NWPA. The NWPA provided states with a limited veto to eliminate nuclear waste from being placed in their state, and provided the same privilege to Native Americans on their reservations. Other provisions of the NWPA also set up the Nuclear Waste Fund that cost the end consumer $.001 per kilowatt hour for those served by nuclear energy. This fund was supposed to provide the nuclear industry and government with enough money to build a permanent disposal site. The government also set up subsidies for nuclear power. It also authorized the Department of Energy (DOE) to conduct research for onsite-dry-storage technology for isolating spent fuel. [This will be covered more later in the paper]. It gave the DOE money to display and build prototypes for the above technologies, and endorsed a federal mid-range storage facility, the Monitored Retrievable Storage System (MRS) [this too, will be covered later in the paper]. The NWPA ordered the DOE to take title and responsibility for all nuclear waste by or on January 1, 1998. This date is rapidly approaching today, but the government is still without a place to put the waste. It seems like the environment is being assigned a lower priority to solve an urgent waste disposal problem that should have been addressed 40 years ago. Scott Saleska, who has done lots of research into the disposal crisis, said Finally, the NWPA did not even address the fundamental issue that still remains today -- the advisability of continuing to use nuclear energy in the absence of a proven method for the permanent disposal of high-level nuclear waste. Today, the largest problem is finding an acceptable way of storing nuclear waste over the long term since most nuclear wastes have a radioactive life of over 100,000 years a period longer than all of recorded history. The four main categories of waste disposal are: a. Land disposal b. sub-seabed disposal c. ice-sheet disposal d. space disposal The most research has been put into what is called deep geologic disposal . This places nuclear waste into a repository below ground, usually in an isolated area with a solid rock formation, this is the primary form of land disposal. The waste is placed at a depth of 600+ meters, about 1/3 of a mile. This was the first option seriously studied by both scientists and the nuclear industry, and is still the most actively pursued option in the U.S. today. The most important issue is the host rock , which is the type of rock surrounding the repository site. The most preferred are salt beds, which in 1957 was endorsed by the National Academy of Sciences as the most promising rock form. The good points are that salt is virtually waterproof, so water will not seep down into the groundwater travelling beneath the waste Also, most fractures in the salt are self-sealing, stopping radiation from simply floating up to the surface through faults or pores in rock. Also, after a short period, the salt will move and seal the waste into a solid mass of salt. The current site being debated for deep-geologic disposal is a site at Yucca Mountain, Nevada. Rock surrounding the site is volcanic tuff, a type of igneous rock formed by a volcanic eruption. Volcanic Tuff is a very stable type of rock, but water can penetrate through it even down to the proposed waste site, 2,500 feet below ground. Also, near this site is an operating gold mine only 6 miles away. The use of this site, then, is undesirable, because future habitants of earth mining in these mountains could uncover the waste we buried there. Nevada's State Legislature also passed two resolutions outlawing disposal of radioactive wastes at this site. Understandably, no one wants waste in their city, state or region. Therefore, the construction and use of a site within the borders of the United States is difficult to achieve. However, in some isolated places, it has been possible to select a site, as with the WIPP (Waste Isolation Pilot Plant) a repository for military produced nuclear wastes. It is located in southeast New Mexico s Eddy County. If finished and used, it will be the nation's first geologic storage facility for the sole purpose of isolating forms of nuclear high-level waste. It is located 650 meters below the desert surface, in a thick salt bed. The facility up to this point has cost $700 million to build. If completed, it will hold 1,100,000 fifty-five-gallon drums filled with nuclear waste, a total of 6,500,000 cubic feet of waste. The site occupies 100 underground acres for storage, and 12 underground acres for research and development. The site, however, has a long list of problems. There are pressurized water pockets below the surface, and if one of them ruptures, it could saturate the waste and possibly launch it straight back up to the surface. Also, water already has leaked into the site, and walls that surround the site have been cracking and allowing salt to creep in which lock the barrels into salt masses too quickly. Documentation and construction permits are missing, and the construction quality was extremely poor. It seems as if speed was more important than safety in the creation of this facility, because it was put on such an urgent timetable. Another alternative for disposal included the addition of Chemical Resynthesis of the waste which converts the waste into a chemical that would be compatible with the host rock, and insoluble to water. It is currently just an idea, and would still require the waste to be buried in a geologic repository. A totally different concept for land disposal is Very Deep Hole Disposal, where the waste is put at the bottom of a hole 10-12 kilometers deep. A total of 800-1200 holes would be needed at each site. There is a much smaller possibility that the waste will migrate to the surface, and the heat inside Earth could cause the waste to be melted into the rock deep underground. However, the depth and prohibitive number of holes would make this very difficult to achieve. Another idea, Melted Rock Disposal, involves placing the high-level waste directly into an underground rock cavity. Eventually enough heat will be created around the canister by the heat from deep within the earth to melt all the rock surrounding the canister, and the melted rock will trap the waste into an immovable rock cluster. One other concept for land disposal, Island Disposal, places the waste into a cavern under an island, in the same manner as Deep Geologic Disposal, except that it is on an island and not on the mainland. The problem, however, is the danger of transporting the waste over the sea, where a shipwreck could cause irreversible harm to the oceans. However, this makes the waste less harmful to humans living on the mainland. Deep-Well Injection, the final plan for disposal on land, is where waste in the form of slurry, a watery mixture of insoluble matter is mixed with cement and clay and injected between layers of rock at depths of up to 500 meters." Used until 1983 by the DOE to dispose 17,300 cubic meters of DOE and Military created low-level waste. Another place to put waste is the bottom of the ocean, in a method known as Sub-Seabed Disposal. In the most common way proposed of Sub-Seabed Disposal is where waste is placed 30 meters under clay on the seabed, most likely in the North Central Pacific, south of the Aleutian Islands, or a similar site. The wastes will be placed in fin-tailed, needle nosed recepticals, and dragged across the sea floor. Clay will eventually re-seal itself over the case. Other variations included using free-fall penetrators, dropped from sea-level, where their momentum will plunge them beneath the seabed. Also, holes could be drilled, with the canisters lowered into these holes. Sub-Seabed disposal has the advantages of the relative long-term stability of the ocean bottom, as compared to the stability on land. The large size of the ocean floor makes it ideal for disposal possibilities. Ocean floors also provide total remoteness from human activities or major concentrations of natural resources. Also, it removes the need to resolve Federal/State disputes over where to put the waste. However, it would require the support of many nations and international organizations. Also, an ocean transport facility, not currently available, would need to be designed and produced. Difficulty is also encountered in documenting the exact location of where we deposited the waste for future generations. Potential for ecologic disruption of the oceans exists if the canisters and clay could form balls of fluid mud or clay and rise to the ocean floor. Up in Greenland and Antarctica another site for possible nuclear waste disposal exists in the massive ice-sheets that cover the land and oceans. The most popular method would be meltdown, where each canister would be placed into a shallow hole, and the heat created internally by the waste will cause the canister to sink down to the bedrock under the ice sheet in approximately 5-10 years. Also, the anchored method would attach each canister to a 200-500 meter cable, which is anchored at the surface. This way, the canister can be retrieved for several hundred years until the whole system sinks, taking 30,000 years to reach the bedrock. There also could be a structure built at the surface, in a method called Surface Storage, in which the waste would be stored inside the facility and can sit there for hundreds of years before sinking. The advantages of these methods would be that the sites are almost totally remote from humans, and the conditions there will be approximately the same for millions of years. However, the long transport distances in moving the waste and high cost and difficulty of working in these polar regions could remove this from practical use. The uncertainty of long-term ice/waste reactions is also still unknown. The final method of long-term storage is Space Disposal, in which the waste is attached to a rocket, and sent into space, where it could be: 1. Sent into the Sun 2. Put into orbit around the Earth or the Sun 3. Sent out of the Solar System altogether The main advantage to this method is that the waste is permanently and totally removed from the Earth, for today, tomorrow and future generations or inhabitants. However, the cost and risk of a launch accident have removed this from serious consideration, though the amount of progress made recently into space research could possibly bring this back, as it seems to represent the best possible way to remove the waste from the environment. Until a site is found for permanent disposal, a variety of methods for mid-term waste disposal have been sought out, starting with the mid-range system proposed in the 1982 NWPA, the MRS, or Monitored Retrievable Storage System. The purpose of such a facility would be to receive and prepare waste from a commercial reactor into temporary storage, before final disposal in a geologic site. Another clause in the NWPA said that no one MRS site could hold more than 10,000 metric tons, and that it cannot be constructed until a permanent site has been completed, so that the MRS site does not turn into a permanent storage facility. Until the completion of a permanent or even mid-term storage facility, the main site for waste storage is at the nuclear plant itself. Many new technologies for waste disposal have emerged from the need for these sites, including various Dry Casks, used to hold nuclear waste and fuel rods. They are explained in the coming paragraphs. The Dry Casks offer the advantages of not using water, so they cannot trigger a chain reaction among themselves, and no low-level waste water is created. They are self-contained, and there is little need for maintenance. There are no mechanical parts that could rust or break, as in many water based temporary storage solutions. It is not totally safe, but as I have found through this research, nothing really is. The oldest and most common dry cask is the Metal Storage Casks. A Metal Storage Cask looks like a casket or a safe and is made of lead or another dense metal. These casks were first experimented with in 1984, as one of the first onsite repositories for nuclear wastes. Also gaining serious support, especially in West Germany, are the Dual Purpose Casks, which are similar to metal, but offer the advantages of use in both storage and transportation. They potentially eliminate the handling operations needed to transfer the irradiated fuel from storage to transportation casks. They are not currently used in the U.S.. The Concrete Storage Casks, which are also similar to metal, have linings of metal inside a highly reinforced concrete body to offer more resistance against corrosion or oxidation of the metal. These are not currently used in the US. The Horizontal Concrete Modules, where in this design, irradiated fuel is stored in large stainless steel containers that are filled with gas and sealed inside a concrete module." One plant is currently using this design, and three others are at various stages of development. This may be the most useful and efficient method of waste disposal. Modular Concrete Vaults: An array of vertical tubes in which intact fuel rods are stored. After the tubes are filled, the tubes are surrounded and encased in concrete. They have been used in Great Britain for 17 years, but have not been set up into the U.S. as of today. Current Plants using Dry Casks for storing their waste include: 1. Virginia Power Company, with Metal Casks at its Surry Nuclear Plant 2. Carolina Power and Light, with Horizontal Concrete Modules at its H.B.Robinson Plant near Hartsville, SC 3. Developmental Stages at: Duke s Power s Oconee Plant near Seneca, SC 4. Developmental Stages at: Baltimore G+E s Calvert s Cliffs facility near Annapolis, MD However, by far the most popular method of isolating waste for the short-term, onsite is the Water Pool Method, where the rods are dropped into large pools of water, which is an excellent barrier to nuclear radiation, to keep emission levels low. However, this method is unsafe, the water can possibly ignite a chain reaction and low-level waste water is created. The effects of radiation on humans are well known, and can be very harmful to all aspects of the body. The average human receives 360 millirems/year or one per day. An average chest x-ray inflicts .03 rads of radiation on the human body, and just living a normal life inflicts .1 rad a year. A rad is a unit measuring the amount of radiation absorbed by the body. Death occurs when the body absorbs over 300-600 rads, and the nuclear worker limit for radiation absorbed is five rads/year. Most nuclear workers receive about .25 rads/year. Obviously, there are many possibilities on how to safely remove nuclear waste from the environment, and all have advantages and disadvantages, and while it is not up to me to play God with such a serious problem, the most logical plan of action is to store the waste onsite in Horizontal Concrete Modules, then have the wastes processed at MRS sites, then sent off into space, where it can be totally separated from the environment. However, someday, very soon, we must make some serious decisions as how to receive, process, and store our nuclear wastes. However, until we decide what to do with this long-lasting poison, maybe the continuation of producing nuclear energy isn't such a good idea, after all. America needs an enforceable, affordable and efficient method of storing this waste, and time is running out. It's time to make something happen. Name : Nuclear.TXT Uploader: John Doe EMail: john@doe.com Language: English Subject: Physics Title: Nuclear Waste. Grade: 91% System: High school Age: 19 years old (when handed in) Country: New York Comments: Where I got Evil House of Cheat Address: my teacher