Nuclear Facts
The Science of Nuclear
Nuclear energy comes from mass-to-energy conversions that occur in the splitting of atoms. Albert Einstein’s famous mathematical formula E = mc2 explains this. The equation says: E [energy] equals m [mass] times c2 [c stands for the speed or velocity of light]. This means that it is mass multiplied by the square of the velocity of light.
Source: OurEnergy.com
Nuclear energy is produced by a controlled nuclear chain reaction and creates heat—which is used to boil water, produce steam, and drive a steam turbine.
Source: OurEnergy.com
Nuclear power can come from the fission of uranium, plutonium or thorium or the fusion of hydrogen into helium. Today it is almost all uranium. The basic energy fact is that the fission of an atom of uranium produces 10 million times the energy produced by the combustion of an atom of carbon from coal.
Source: OurEnergy.com
The sun uses nuclear fusion of hydrogen atoms into helium atoms. This gives off heat and light and other radiation.
Source: OurEnergy.com
Uranium Is Found in Nature but Must Be Processed into Fuel
Uranium is nonrenewable, though it is a common metal found in rocks all over the world. Uranium occurs in nature in combination with small amounts of other elements.
Nuclear plants use a certain kind of uranium, U-235, as fuel because its atoms are easily split apart. Though uranium is quite common, about 100 times more common than silver, U-235 is relatively rare.
Special Nuclear Material
What is meant by “special nuclear material”?
“Special nuclear material” (SNM) is defined by Title I of the Atomic Energy Act of 1954 as plutonium, uranium-233, or uranium enriched in the isotopes uranium-233 or uranium-235. The definition includes any other material that the Commission determines to be special nuclear material, but does not include source material. The NRC has not declared any other material as SNM.
Where does special nuclear material come from?
Uranium-233 and plutonium do not occur naturally but can be formed in nuclear reactors and extracted from the highly radioactive spent fuel by chemical separation. Uranium-233 can be produced in special reactors that use thorium as fuel. Only small quantities of uranium-233 have ever been made in the United States. Plutonium is produced in reactors using U-238/U-235 fuel. No U.S. commercial plutonium reprocessing plant is currently licensed by the NRC for operation. Uranium enriched in uranium-235 is created by an enrichment facility (see Uranium Enrichment). The NRC regulates two gaseous diffusion enrichment plants operated by the U.S. Enrichment Corporation.
Nuclear Safety
Nuclear energy is now very safe source of energy because safety measures are taken to its maximum so new Chernobyl is very unlikely to happen.
Source: OurEnergy.com
Nuclear power plants have experienced an admirable safety record. About 20% of electricity generated in the U.S. comes from nuclear power, and in the last forty years of this production, not one single fatality has occurred as a result of the operation of a civilian nuclear power plant in the United States.
Source: OurEnergy.com
Backgrounder on the Three Mile Island Accident
Summary of Events
The accident began about 4:00 a.m. on March 28, 1979, when the plant experienced a failure in the secondary, non nuclear section of the plant. The main feedwater pumps stopped running, caused by either a mechanical or electrical failure, which prevented the steam generators from removing heat. First the turbine, then the reactor automatically shut down. Immediately, the pressure in the primary system (the nuclear portion of the plant) began to increase. In order to prevent that pressure from becoming excessive…
Continue reading at U.S. Nuclear Regulatory Commision
Nuclear Waste
Compared to other non-carbon-based and carbon-neutral energy options, nuclear power plants require far less land area. For a 1000 MW plant, site requirements are estimated as follows: nuclear, 1-4 km2; solar or photovoltaic park, 20-50 km2; a wind field, 50-150 km2; and biomass, 4.000-6.000 km2.
Source: OurEnergy.com
The nuclear power industry generates approximately 2,000 tons of solid waste annually in the United States. In comparison, coal fueled power plants produce 100,000,000 tons of ash and sludge annually, and this ash is laced with poisons such as mercury and nitric oxide.
Source: OurEnergy.com
Even this, 2,000 tons of nuclear waste is not a technical problem. Reprocessing of nuclear fuel, and the implementation of Integral Fast Reactor technology, will enable us to turn the vast majority of what is currently considered waste into energy.
Source: OurEnergy.com
Why is control of special nuclear material important?
Congress enacted Title I of the Atomic Energy Act of 1954, as part of President Eisenhower’s Atoms for Peace program, including the clause:
Source and special nuclear material, production facilities, and utilization facilities are affected with the public interest, and regulation by the United States of the production and utilization of atomic energy and of the facilities used in connection therewith is necessary in the national interest to assure the common defense and security and to protect the health and safety of the public.
Special nuclear material is only mildly radioactive, but it includes some fissile material — uranium-233, uranium-235, and plutonium-239 — that, in concentrated form, can be the primary ingredients of nuclear explosives. These materials, in amounts greater than formula quantities, are defined as “strategic special nuclear material” (SSNM). The uranium-235 content of low-enriched uranium can be concentrated (i.e., enriched) to make highly enriched uranium, the primary ingredient of an atomic bomb.
Low-Level Waste
Low-level waste 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, reactor water treatment residues, equipments and tools, luminous dials, medical tubes, swabs, injection needles, syringes, and laboratory animal carcasses and tissues. The radioactivity can range from just above background levels found in nature to very highly radioactive in certain cases such as parts from inside the reactor vessel in a nuclear power plant. Low-level waste is typically stored on-site by licensees, either until it has decayed away and can be disposed of as ordinary trash, or until amounts are large enough for shipment to a low-level waste disposal site in containers approved by the Department of Transportation.
High-Level Waste
High-level radioactive wastes are the highly radioactive materials produced as a byproduct of the reactions that occur inside nuclear reactors.
High-level wastes take one of two forms:
- Spent (used) reactor fuel when it is accepted for disposal
- Waste materials remaining after spent fuel is reprocessed
Spent nuclear fuel is used fuel from a reactor that is no longer efficient in creating electricity, because its fission process has slowed. However, it is still thermally hot, highly radioactive, and potentially harmful. Until a permanent disposal repository for spent nuclear fuel is built, licensees must safely store this fuel at their reactors.
Reprocessing extracts isotopes from spent fuel that can be used again as reactor fuel. Commercial reprocessing is currently not practiced in the United States, although it has been allowed in the past. However, significant quantities of high-level radioactive waste are produced by the defense reprocessing programs at Department of Energy (DOE) facilities, such as Hanford, Washington, and Savannah River, South Carolina, and by commercial reprocessing operations at West Valley, New York. These wastes, which are generally managed by DOE, are not regulated by NRC. However they must be included in any high-level radioactive waste disposal plans, along with all high-level waste from spent reactor fuel.
Because of their highly radioactive fission products, high-level waste and spent fuel must be handled and stored with care. Since the only way radioactive waste finally becomes harmless is through decay, which for high-level wastes can take hundreds of thousands of years, the wastes must be stored and finally disposed of in a way that provides adequate protection of the public for a very long time.
Because of their highly radioactive fission products, high-level waste and spent fuel must be handled and stored with care. Since the only way radioactive waste finally becomes harmless is through decay, which for high-level wastes can take hundreds of thousands of years, the wastes must be stored and finally disposed of in a way that provides adequate protection of the public for a very long time.
Criteria for Waste Incidental to Reprocessing
Under the Ronald W. Reagan National Defense Authorization Act for Fiscal Year 2005 (NDAA ), the Secretary of Energy, in consultation with the U.S. Nuclear Regulatory Commission (NRC), may render waste determinations regarding the radioactive byproducts that result from reprocessing spent (depleted) nuclear fuel. In so doing, the Secretary may determine that the waste byproducts in question are actually waste incidental to reprocessing (WIR), rather than high-level radioactive waste (HLW).
Such waste determinations are based on whether the byproducts in question meet all of the criteria set forth in Section 3116 of the NDAA (Public Law 108-375, 2004 ) for the Covered States. (Section 3116 currently identifies the Covered States as Idaho and South Carolina.) Specifically, Section 3116 establishes the following criteria for determining that waste is not HLW:
- The waste does not require permanent isolation in a deep geologic repository for spent nuclear fuel or HLW.
- The waste has had highly radioactive radionuclides removed to the maximum extent practical.
- The waste meets either of the following conditions:
- The waste does not exceed concentration limits for Class C low-level waste (LLW) and will be disposed of in compliance with the performance objectives set forth in Subpart C of Title 10, Part 61, of the Code of Federal Regulations (10 CFR Part 61), “Licensing Requirements for Land Disposal of Radioactive Waste”; or
- The waste exceeds concentration limits for Class C LLW but will be disposed of in compliance with the performance objectives set forth in Subpart C of 10 CFR Part 61, and pursuant to plans that DOE developed in consultation with the NRC.
As described in paragraphs (c) and (d) of Section 3116 of the NDAA, these criteria apply to certain waste that will be disposed of in South Carolina and Idaho, but not to waste that will be transported out of those States. Moreover, for other States, alternative criteria for waste determinations are specified in DOE Order 435.1 , “Radioactive Waste Management,” the associated “Radioactive Waste Management Manual,” or the West Valley Policy Statement (for West Valley only). Nonetheless, in general, the various sets of criteria share several similarities, including the fact that all of the sets of criteria refer to the performance objectives set forth in Subpart C of 10 CFR Part 61.
Storage of Spent Nuclear Fuel
What We Regulate
There are two acceptable storage methods for spent fuel after it is removed from the reactor core:
- Spent Fuel Pools – Currently, most spent nuclear fuel is safely stored in specially designed pools at individual reactor sites around the country.
- Dry Cask Storage – If pool capacity is reached, licensees may move toward use of above-ground dry storage casks.
How We Regulate
The NRC regulates spent fuel through a combination of regulatory requirements, licensing; safety oversight, including inspection, assessment of performance; and enforcement; operational experience evaluation; and regulatory support activities. (For general information, see the How We Regulate page.)
Transportation of Spent Nuclear Fuel
What We Regulate
Spent nuclear fuel refers to uranium-bearing fuel elements that have been used at commercial nuclear reactors and that are no longer producing enough energy to sustain a nuclear reaction. Once the spent fuel is removed from the reactor the fission process has stopped, but the spent fuel assemblies still generate significant amounts of radiation and heat. Because of the residual hazard, spent fuel must be shipped in containers or casks that shield and contain the radioactivity and dissipate the heat.
Over the last 30 years, thousands of shipments of commercially generated spent nuclear fuel have been made throughout the United States without causing any radiological releases to the environment or harm to the public.
Most of these shipments occur between different reactors owned by the same utility to share storage space for spent fuel, or they may be shipped to a research facility to perform tests on the spent fuel itself. In the near future, because of a potential high-level waste repository being built, the number of these shipments by road and rail is expected to increase.
How We Regulate
The NRC regulates spent fuel transportation through a combination of safety and security requirements, certification of transportation casks, inspections, and a system of monitoring to ensure that requirements are being met. (For general information, see the How We Regulate page.)
Light water reactor
A term used to describe reactors using ordinary water as coolant, including boiling water reactors (BWRs) and pressurized water reactors (PWRs), the most common types used in the United States.
Decommissioning of Nuclear Facilities
How We Regulate
Decommissioning program activities include (1) developing regulations and guidance to assist staff and the regulated community; (2) conducting research to develop data, techniques, and models used to assess public exposure from the release of radioactive material resulting from site decommissioning; (3) reviewing and approving decommissioning plans (DPs) and license termination plans (LTPs); (4) reviewing and approving license amendment requests for decommissioning facilities; (5) inspecting licensed and non-licensed facilities undergoing decommissioning; (6) developing environmental assessments (EAs) and environmental impact statements (EISs) to support the NRC’s reviews of decommissioning activities; (7) reviewing and approving final site status survey reports; and (8) conducting confirmatory surveys.
The NRC ensures that safety requirements are being met throughout the decommissioning process by reviewing decommissioning or license termination plans, conducting inspections, and monitoring the status of activities to ensure that radioactive contamination is reduced or stabilized.
Nuclear Usage
Nuclear energy (nuclear power) accounts for about 19 percent of the total electricity generated in the United States, an amount comparable to all the electricity used in California, Texas and New York, three most populous states.
Source: OurEnergy.com
In the United States, nuclear power supplies about 15 percent of the electricity overall, but some states get more power from nuclear plants than others. There are more than 400 nuclear power plants around the world, with more than 100 in the United States.
Source: OurEnergy.com