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86-703: The nuclear power plant is named after a ferry that operated at the site until the middle of the 20th century. (Brown's Ferry) Browns Ferry was TVA's first nuclear power plant; its approval occurred on June 17, 1966 and construction began in September 1966. In 1974, the time of its initial operation, it was the largest nuclear plant in the world. It was the first nuclear plant to use units capable of generating more than 1 gigawatt of power. The lake provides main cooling, and 7 additional Mechanical Draft "helper" cooling towers assist during limitations on water temperature. The 600 ft concrete chimney vents gases. In 2006,

172-615: A brief period of outage. An NRC Unusual Event, the lowest level of emergency classification , was declared due to loss of power exceeding 15 minutes. Additionally, a small oil leak was found on one generator. Due to widespread transmission grid damage from the storms, Browns Ferry was unable to produce power for the grid and significant blackouts occurred throughout the Southeastern United States. A drain line leaked 100-200 gallons of water containing tritium levels above acceptable EPA drinking water standards. The leak

258-406: A cable, radiates an electromagnetic field . Likewise, any conductor or cable will pick up energy from any existing electromagnetic field around it. These effects are often undesirable, in the first case amounting to unwanted transmission of energy which may adversely affect nearby equipment or other parts of the same piece of equipment; and in the second case, unwanted pickup of noise which may mask

344-614: A capacity factor of 99.70%. The power update of 155 MWe was completed in July 2018. TVA decided to shut the entire plant down and keep it shut down indefinitely in order to focus on making improvements to all three units in order to bring it back into regulatory compliance following extremely negative assessments from the NRC. Unit 2 finally resumed operation on May 24, 1991, with Unit 3 following it on November 1, 1995, although Unit 1 did not resume operation until June 2, 2007. Cooling tower #4 (which

430-465: A condenser. The condenser is a heat exchanger which is connected to a secondary side such as a river or a cooling tower . The water is then pumped back into the steam generator and the cycle begins again. The water-steam cycle corresponds to the Rankine cycle . The nuclear reactor is the heart of the station. In its central part, the reactor's core produces heat due to nuclear fission. With this heat,

516-442: A coolant is heated as it is pumped through the reactor and thereby removes the energy from the reactor. The heat from nuclear fission is used to raise steam, which runs through turbines , which in turn power the electrical generators. Nuclear reactors usually rely on uranium to fuel the chain reaction. Uranium is a very heavy metal that is abundant on Earth and is found in sea water as well as most rocks. Naturally occurring uranium

602-402: A facility has been completely decommissioned it is released from regulatory control, and the licensee of the station no longer has responsibility for its nuclear safety. Generally speaking, nuclear stations were originally designed for a life of about 30 years. Newer stations are designed for a 40 to 60-year operating life. The Centurion Reactor is a future class of nuclear reactor that

688-438: A flame retardant paint, was used as a firestop . The fire spread from the temporary seal into the foamed plastic, causing significant damage to the reactor control cabling in the station. An NRC bulletin explained the circumstances of the fire. The fire started in the cable spreading room at a cable penetration through the wall between the cable spreading room and the reactor building for Unit 1. A slight differential pressure

774-618: A hand drill and turning while maintaining moderate tension on the line. Where the interfering signal has a wavelength that is long compared to the pitch of the twisted pair, alternate lengths of wires develop opposing voltages, tending to cancel the effect of the interference. Electrical cable jacket material is usually constructed of flexible plastic which will burn. The fire hazard of grouped cables can be significant. Cables jacketing materials can be formulated to prevent fire spread (see Mineral-insulated copper-clad cable ) . Alternately, fire spread amongst combustible cables can be prevented by

860-401: A leaky hydraulic control pipe in the turbine hall burst, spilling about 600 US gallons (2,300 L; 500 imp gal) of non-radioactive fluid, and the newly restarted reactor was temporarily powered down. Reactor power-up and tests resumed on May 27 and the unit started supplying power to the electricity supply grid on June 2, 2007, reaching full power on June 8. The Browns Ferry restart

946-404: A nuclear reactor heats the reactor coolant. The coolant may be water or gas, or even liquid metal, depending on the type of reactor. The reactor coolant then goes to a steam generator and heats water to produce steam. The pressurized steam is then usually fed to a multi-stage steam turbine . After the steam turbine has expanded and partially condensed the steam, the remaining vapor is condensed in

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1032-683: A nuclear reactor was used to generate electricity was on December 21, 1951, at the Experimental Breeder Reactor I , powering four light bulbs. On June 27, 1954, the world's first nuclear power station to generate electricity for a power grid , the Obninsk Nuclear Power Plant , commenced operations in Obninsk , in the Soviet Union . The world's first full scale power station, Calder Hall in

1118-483: A nuclear station is smaller than the fuel cost for operation of coal or gas plants. Since most of the cost of nuclear power plant is capital cost, there is almost no cost saving by running it at less than full capacity. Nuclear power plants are routinely used in load following mode on a large scale in France, although "it is generally accepted that this is not an ideal economic situation for nuclear stations". Unit A at

1204-516: A number of long-established projects are struggling to find financing, notably Belene in Bulgaria and the additional reactors at Cernavodă in Romania , and some potential backers have pulled out. Where cheap gas is available and its future supply relatively secure, this also poses a major problem for nuclear projects. Analysis of the economics of nuclear power must take into account who bears

1290-726: A partial product (e.g. to be soldered onto a printed circuit board with a connector mounted to the housing). Cable assemblies can also take the form of a cable tree or cable harness , used to connect many terminals together. Electrical cables are used to connect two or more devices, enabling the transfer of electrical signals or power from one device to the other. Long-distance communication takes place over undersea communication cables . Power cables are used for bulk transmission of alternating and direct current power, especially using high-voltage cable . Electrical cables are extensively used in building wiring for lighting, power and control circuits permanently installed in buildings. Since all

1376-444: A previous goal aimed to reduce nuclear electricity generation share to lower than fifty percent by 2025, this target was postponed to 2035 in 2019 and ultimately discarded in 2023. Russia continues to export the most nuclear power plants in the world, with projects across various countries: as of July 2023, Russia was constructing 19 out of 22 reactors constructed by foreign vendors; however, some exporting projects were canceled due to

1462-591: A significantly different evaluation of the economics of new nuclear power stations. Following the 2011 Fukushima nuclear accident in Japan , costs are likely to go up for currently operating and new nuclear power stations, due to increased requirements for on-site spent fuel management and elevated design basis threats. However many designs, such as the currently under construction AP1000, use passive nuclear safety cooling systems, unlike those of Fukushima I which required active cooling systems, which largely eliminates

1548-413: A slight decrease from the 2653 TWh produced in 2021. Thirteen countries generated at least one-quarter of their electricity from nuclear sources. Notably, France relies on nuclear energy for about 70% of its electricity needs, while Ukraine , Slovakia , Belgium , and Hungary source around half their power from nuclear. Japan , which previously depended on nuclear for over a quarter of its electricity,

1634-427: A small enough volume to become supercritical. Most reactors require continuous temperature control to prevent a core meltdown , which has occurred on a few occasions through accident or natural disaster, releasing radiation and making the surrounding area uninhabitable. Plants must be defended against theft of nuclear material and attack by enemy military planes or missiles. The most serious accidents to date have been

1720-482: A three-year research study of offshore floating nuclear power generation. In October 2022, NuScale Power and Canadian company Prodigy announced a joint project to bring a North American small modular reactor based floating plant to market. The economics of nuclear power plants is a controversial subject, and multibillion-dollar investments ride on the choice of an energy source. Nuclear power stations typically have high capital costs, but low direct fuel costs, with

1806-580: A worldwide perspective, long-term waste storage costs are uncertain. Construction, or capital cost aside, measures to mitigate global warming such as a carbon tax or carbon emissions trading , increasingly favor the economics of nuclear power. Further efficiencies are hoped to be achieved through more advanced reactor designs, Generation III reactors promise to be at least 17% more fuel efficient, and have lower capital costs, while Generation IV reactors promise further gains in fuel efficiency and significant reductions in nuclear waste. In Eastern Europe,

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1892-496: Is a thermal power station in which the heat source is a nuclear reactor . As is typical of thermal power stations, heat is used to generate steam that drives a steam turbine connected to a generator that produces electricity . As of September 2023 , the International Atomic Energy Agency reported that there were 410 nuclear power reactors in operation in 32 countries around

1978-501: Is about 1/3 of solar and 1/45 of natural gas and 1/75 of coal . Newer models, like HPR1000 , produce even less carbon dioxide during the whole operating life, as little as 1/8 of power plants using gen II reactors for 1.31g/kWh. Electrical cable An electrical cable is an assembly of one or more wires running side by side or bundled, which is used as an electrical conductor to carry electric current . Electrical cables are used to connect two or more devices, enabling

2064-442: Is also used to provide lubrication between strands. Tinning was used to help removal of rubber insulation. Tight lays during stranding makes the cable extensible (CBA – as in telephone handset cords). In the 19th century and early 20th century, electrical cable was often insulated using cloth, rubber or paper. Plastic materials are generally used today, except for high-reliability power cables. The first thermoplastic used

2150-527: Is anticipated to resume similar levels of nuclear energy utilization. Over the last 15 years, the United States has seen a significant improvement in the operational performance of its nuclear power plants, enhancing their utilization and efficiency, adding the output equivalent to 19 new 1000 MWe reactors without actual construction. In France, nuclear power plants still produce over sixty percent of this country's total power generation in 2022. While

2236-503: Is being designed to last 100 years. One of the major limiting wear factors is the deterioration of the reactor's pressure vessel under the action of neutron bombardment, however in 2018 Rosatom announced it had developed a thermal annealing technique for reactor pressure vessels which ameliorates radiation damage and extends service life by between 15 and 30 years. Nuclear stations are used primarily for base load because of economic considerations. The fuel cost of operations for

2322-431: Is found in two different isotopes : uranium-238 (U-238), accounting for 99.3% and uranium-235 (U-235) accounting for about 0.7%. U-238 has 146 neutrons and U-235 has 143 neutrons. Different isotopes have different behaviors. For instance, U-235 is fissile which means that it is easily split and gives off a lot of energy making it ideal for nuclear energy. On the other hand, U-238 does not have that property despite it being

2408-536: Is licensed to operate through June 28, 2034. Unit 2 generated 8,396 GWh of electricity in 2017, achieving a capacity factor of 86.81%. Unit 2 returned to service in 1991, after all three reactors were shut down in 1985. During a drought in August 2007, Unit 2 was shut down for one day because water temperature in the Tennessee River rose too high for the water to be used for cooling and then discharged back into

2494-459: Is maintained (by design) across this wall, with the higher pressure being on the cable spreading room side. The penetration seal originally present had been breached to install additional cables required by a design modification. Site personnel were resealing the penetration after cable installation and were checking the airflow through a temporary seal with a candle flame prior to installing the permanent sealing material. The temporary sealing material

2580-426: Is not greatly effective against low-frequency magnetic fields, however - such as magnetic "hum" from a nearby power transformer . A grounded shield on cables operating at 2.5 kV or more gathers leakage current and capacitive current, protecting people from electric shock and equalizing stress on the cable insulation. Coaxial design helps to further reduce low-frequency magnetic transmission and pickup. In this design

2666-429: Is the only nuclear facility that does not use a natural body of water for cooling, instead it uses treated sewage from the greater Phoenix metropolitan area. The water coming from the cooling body of water is either pumped back to the water source at a warmer temperature or returns to a cooling tower where it either cools for more uses or evaporates into water vapor that rises out the top of the tower. The water level in

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2752-489: The BWR , the steam is directed into the suppression chamber and condenses there. The chambers on a heat exchanger are connected to the intermediate cooling circuit. The main condenser is a large cross-flow shell and tube heat exchanger that takes wet vapor, a mixture of liquid water and steam at saturation conditions, from the turbine-generator exhaust and condenses it back into sub-cooled liquid water so it can be pumped back to

2838-786: The Nuclear Regulatory Commission (NRC) renewed the licenses for all three reactors, extending their operation for an additional twenty years past their original 40-year licensing period. TVA employs 1,500 people at the plant, making it the second largest employer in Limestone County, Alabama after only the Toyota-Mazda factory near Greenbrier During the January 2024 Snowstorms , the Browns Ferry Plant reached its capacity of 3,954mw, and

2924-496: The Russian invasion of Ukraine . Meanwhile, China continues to advance in nuclear energy: having 25 reactors under construction by late 2023, China is the country with the most reactors being built at one time in the world. Nuclear decommissioning is the dismantling of a nuclear power station and decontamination of the site to a state no longer requiring protection from radiation for the general public. The main difference from

3010-678: The UAE launched the Arab region's first-ever nuclear energy plant. Unit 1 of the Barakah plant in the Al Dhafrah region of Abu Dhabi commenced generating heat on the first day of its launch, while the remaining 3 Units are being built. However, Nuclear Consulting Group head, Paul Dorfman, warned the Gulf nation's investment into the plant as a risk "further destabilizing the volatile Gulf region, damaging

3096-657: The United Kingdom , opened on October 17, 1956 and was also meant to produce plutonium . The world's first full scale power station solely devoted to electricity production was the Shippingport Atomic Power Station in Pennsylvania , United States, which was connected to the grid on December 18, 1957. The conversion to electrical energy takes place indirectly, as in conventional thermal power stations. The fission in

3182-424: The 1970s and 1980s, when it "reached an intensity unprecedented in the history of technology controversies," in some countries. Proponents argue that nuclear power is a sustainable energy source which reduces carbon emissions and can increase energy security if its use supplants a dependence on imported fuels. Proponents advance the notion that nuclear power produces virtually no air pollution, in contrast to

3268-485: The 1979 Three Mile Island accident , the 1986 Chernobyl disaster , and the 2011 Fukushima Daiichi nuclear disaster , corresponding to the beginning of the operation of generation II reactors . Professor of sociology Charles Perrow states that multiple and unexpected failures are built into society's complex and tightly coupled nuclear reactor systems. Such accidents are unavoidable and cannot be designed around. An interdisciplinary team from MIT has estimated that given

3354-572: The Brussels supplementary convention, and the Vienna Convention on Civil Liability for Nuclear Damage . However states with a majority of the world's nuclear power stations, including the U.S., Russia, China and Japan, are not party to international nuclear liability conventions. The nuclear power debate about the deployment and use of nuclear fission reactors to generate electricity from nuclear fuel for civilian purposes peaked during

3440-568: The TVA is saving millions of dollars in fuel costs and accumulating a database of recycled uranium reactions in LWR use. Unit 3 is a 1,260 MWe net BWR /4 built by General Electric that originally came online on August 18, 1976 with a capacity of 1,105 MWe net, and is licensed to operate through July 2, 2036. Unit 3 returned to service in 1995 after all three units were shut down in 1985 for maintenance and repairs. Unit 3 generated 9,651 GWh in 2017, achieving

3526-455: The annual electricity generation at the site in GWh. Unit 1 is a 1,256 MWe net BWR /4 built by General Electric. Construction started on Unit 1 on September 12, 1966 and first powered up for testing on December 20, 1973. Commercial operation began on August 1, 1974. It was licensed to operate through December 20, 2013. Unit 1 was shut down for a year after a fire in 1975 damaged the unit. The unit

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3612-417: The application of fire retardant coatings directly on the cable exterior, or the fire threat can be isolated by the installation of boxes constructed of noncombustible materials around the bulk cable installation. CENELEC HD 361 is a ratified standard published by CENELEC, which relates to wire and cable marking type, whose goal is to harmonize cables. Deutsches Institut für Normung (DIN, VDE) has released

3698-557: The chief viable alternative of fossil fuel. Proponents also believe that nuclear power is the only viable course to achieve energy independence for most Western countries. They emphasize that the risks of storing waste are small and can be further reduced by using the latest technology in newer reactors, and the operational safety record in the Western world is excellent when compared to the other major kinds of power plants. Opponents say that nuclear power poses many threats to people and

3784-402: The circuit conductors required can be installed in a cable at one time, installation labor is saved compared to certain other wiring methods. Physically, an electrical cable is an assembly consisting of one or more conductors with their own insulations and optional screens, individual coverings, assembly protection and protective coverings. Electrical cables may be made more flexible by stranding

3870-493: The costs of fuel extraction, processing, use and spent fuel storage internalized costs. Therefore, comparison with other power generation methods is strongly dependent on assumptions about construction timescales and capital financing for nuclear stations. Cost estimates take into account station decommissioning and nuclear waste storage or recycling costs in the United States due to the Price Anderson Act . With

3956-518: The desired signal being carried by the cable, or, if the cable is carrying power supply or control voltages, pollute them to such an extent as to cause equipment malfunction. The first solution to these problems is to keep cable lengths in buildings short since pick up and transmission are essentially proportional to the length of the cable. The second solution is to route cables away from trouble. Beyond this, there are particular cable designs that minimize electromagnetic pickup and transmission. Three of

4042-424: The destruction of a turbine in operation from flying towards the reactor. In the case of a pressurized water reactor, the steam turbine is separated from the nuclear system. To detect a leak in the steam generator and thus the passage of radioactive water at an early stage, an activity meter is mounted to track the outlet steam of the steam generator. In contrast, boiling water reactors pass radioactive water through

4128-458: The dismantling of other power stations is the presence of radioactive material that requires special precautions to remove and safely relocate to a waste repository. Decommissioning involves many administrative and technical actions. It includes all clean-up of radioactivity and progressive demolition of the station. Once a facility is decommissioned, there should no longer be any danger of a radioactive accident or to any persons visiting it. After

4214-534: The energy-intensive stages of the nuclear fuel chain are considered, from uranium mining to nuclear decommissioning , nuclear power is not a low-carbon electricity source despite the possibility of refinement and long-term storage being powered by a nuclear facility. Those countries that do not contain uranium mines cannot achieve energy independence through existing nuclear power technologies. Actual construction costs often exceed estimates, and spent fuel management costs are difficult to define. On 1 August 2020,

4300-402: The environment and raising the possibility of nuclear proliferation." Nuclear power plants do not produce greenhouse gases during operation. Older nuclear power plants, like ones using second-generation reactors , produce approximately the same amount of carbon dioxide during the whole life cycle of nuclear power plants for an average of about 11g/kWh, as much power generated by wind , which

4386-775: The environment, and that costs do not justify benefits. Threats include health risks and environmental damage from uranium mining , processing and transport, the risk of nuclear weapons proliferation or sabotage, and the problem of radioactive nuclear waste . Another environmental issue is discharge of hot water into the sea. The hot water modifies the environmental conditions for marine flora and fauna. They also contend that reactors themselves are enormously complex machines where many things can and do go wrong, and there have been many serious nuclear accidents . Critics do not believe that these risks can be reduced through new technology , despite rapid advancements in containment procedures and storage methods. Opponents argue that when all

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4472-411: The environment. In addition, many reactors are equipped with a dome of concrete to protect the reactor against both internal casualties and external impacts. The purpose of the steam turbine is to convert the heat contained in steam into mechanical energy. The engine house with the steam turbine is usually structurally separated from the main reactor building. It is aligned so as to prevent debris from

4558-444: The estimated risk of an earthquake intense enough to cause core damage to reactor one was 1 in 270,270, and for reactors two and three, the risk was 1 in 185,185. [REDACTED] Media related to Browns Ferry Nuclear Power Plant at Wikimedia Commons Nuclear power plant A nuclear power plant ( NPP ), also known as a nuclear power station ( NPS ), nuclear generating station ( NGS ) or atomic power station ( APS )

4644-612: The event was that the VFD controls malfunctioned due to excessive traffic on the connected plant Integrated Control System (ICS) network. Corrective actions included installing network firewalls that limit the connections and traffic to the VFD controllers. At 5:01 PM on April 27, 2011, all three reactors scrammed due to loss of external power caused by a tornado in the vicinity of the plant. Control rod insertion and cooling procedures operated as designed with no physical damage or release of radiation. Diesel backup generators provided power after

4730-525: The expected growth of nuclear power from 2005 to 2055, at least four serious nuclear accidents would be expected in that period. The MIT study does not take into account improvements in safety since 1970. Nuclear power works under an insurance framework that limits or structures accident liabilities in accordance with the Paris Convention on Third Party Liability in the Field of Nuclear Energy ,

4816-484: The fire on the other side of the wall from the point of ignition was not recognized until significant damage to cables related to the control of Units 1 and 2 had occurred. This later resulted in the Nuclear Regulatory Commission making significant additions to the standards for fire protection through the publication of 10CFR50.48 and Appendix R. According to the Nuclear Information and Resource Service ,

4902-399: The foil or mesh shield has a circular cross section and the inner conductor is exactly at its center. This causes the voltages induced by a magnetic field between the shield and the core conductor to consist of two nearly equal magnitudes which cancel each other. A twisted pair has two wires of a cable twisted around each other. This can be demonstrated by putting one end of a pair of wires in

4988-406: The hot coolant is used as a heat source for a boiler, and the pressurized steam from that drives one or more steam turbine driven electrical generators . In the event of an emergency, safety valves can be used to prevent pipes from bursting or the reactor from exploding. The valves are designed so that they can derive all of the supplied flow rates with little increase in pressure. In the case of

5074-426: The hours over which the fixed cost of construction can be amortized. Nuclear power plants have a carbon footprint comparable to that of renewable energy such as solar farms and wind farms , and much lower than fossil fuels such as natural gas and coal . Nuclear power plants are among the safest modes of electricity generation, comparable to solar and wind power plants. The first time that heat from

5160-607: The need to spend more on redundant back up safety equipment. According to the World Nuclear Association , as of March 2020: The Russian state nuclear company Rosatom is the largest player in international nuclear power market, building nuclear plants around the world. Whereas Russian oil and gas were subject to international sanctions after the Russian full-scale invasion of Ukraine in February 2022, Rosatom

5246-484: The newly restarted Unit 1 does not comply with these standards. Unit 3 was not affected by the accident. This event was pivotal not just for firestopping in the nuclear field, but also in commercial and industrial construction . While the nuclear field went to installations of silicone foam, a wider array of firestops became prevalent in non-nuclear construction. Unit 2 is a 1,259 MWe net BWR /4 built by General Electric that originally came online on August 2, 1974, and

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5332-483: The now decommissioned German Biblis Nuclear Power Plant was designed to modulate its output 15% per minute between 40% and 100% of its nominal power. Russia has led in the practical development of floating nuclear power stations , which can be transported to the desired location and occasionally relocated or moved for easier decommissioning. In 2022, the United States Department of Energy funded

5418-535: The principal design techniques are shielding , coaxial geometry, and twisted-pair geometry. Shielding makes use of the electrical principle of the Faraday cage . The cable is encased for its entire length in foil or wire mesh. All wires running inside this shielding layer will be to a large extent decoupled from external electrical fields, particularly if the shield is connected to a point of constant voltage, such as earth or ground . Simple shielding of this type

5504-474: The prospect that all spent nuclear fuel could potentially be recycled by using future reactors, generation IV reactors are being designed to completely close the nuclear fuel cycle . However, up to now, there has not been any actual bulk recycling of waste from a NPP, and on-site temporary storage is still being used at almost all plant sites due to construction problems for deep geological repositories . Only Finland has stable repository plans, therefore from

5590-427: The reactor by the condensate and feedwater pumps. In the main condenser, the wet vapor turbine exhaust come into contact with thousands of tubes that have much colder water flowing through them on the other side. The cooling water typically come from a natural body of water such as a river or lake. Palo Verde Nuclear Generating Station , located in the desert about 97 kilometres (60 mi) west of Phoenix, Arizona,

5676-540: The risks of future uncertainties. To date all operating nuclear power stations were developed by state-owned or regulated utilities where many of the risks associated with construction costs, operating performance, fuel price, and other factors were borne by consumers rather than suppliers. Many countries have now liberalized the electricity market where these risks and the risk of cheaper competitors emerging before capital costs are recovered, are borne by station suppliers and operators rather than consumers, which leads to

5762-511: The river. Beginning in 2005 Unit 2 was loaded with BLEU (Blended Low Enriched Uranium) recovered by the DOE from weapons programs. This fuel contains quantities of U-236 and other contaminants because it was made from reprocessed fuel from weapons program reactors and therefore has slightly different characteristics when used in a reactor as compared to fresh uranium fuel. By making use of this fuel, which would otherwise have been disposed of as waste,

5848-407: The same element. Different isotopes also have different half-lives . U-238 has a longer half-life than U-235, so it takes longer to decay over time. This also means that U-238 is less radioactive than U-235. Since nuclear fission creates radioactivity, the reactor core is surrounded by a protective shield. This containment absorbs radiation and prevents radioactive material from being released into

5934-693: The steam generator and the nuclear reactor is controlled using the feedwater system. The feedwater pump has the task of taking the water from the condensate system, increasing the pressure and forcing it into either the steam generators—in the case of a pressurized water reactor — or directly into the reactor, for boiling water reactors . Continuous power supply to the plant is critical to ensure safe operation. Most nuclear stations require at least two distinct sources of offsite power for redundancy. These are usually provided by multiple transformers that are sufficiently separated and can receive power from multiple transmission lines. In addition, in some nuclear stations,

6020-487: The steam turbine, so the turbine is kept as part of the radiologically controlled area of the nuclear power station. The electric generator converts mechanical power supplied by the turbine into electrical power. Low-pole AC synchronous generators of high rated power are used. A cooling system removes heat from the reactor core and transports it to another area of the station, where the thermal energy can be harnessed to produce electricity or to do other useful work. Typically

6106-463: The transfer of electrical signals , power , or both from one device to the other. Physically, an electrical cable is an assembly consisting of one or more conductors with their own insulations and optional screens, individual coverings, assembly protection and protective covering. One or more electrical cables and their corresponding connectors may be formed into a cable assembly, which is not necessarily suitable for connecting two devices but can be

6192-477: The turbine generator can power the station's loads while the station is online, without requiring external power. This is achieved via station service transformers which tap power from the generator output before they reach the step-up transformer. Nuclear power plants generate approximately 10% of global electricity, sourced from around 440 reactors worldwide. They are recognized as a significant provider of low-carbon electricity , accounting for about one-quarter of

6278-548: The wires. In this process, smaller individual wires are twisted or braided together to produce larger wires that are more flexible than solid wires of similar size. Bunching small wires before concentric stranding adds the most flexibility. Copper wires in a cable may be bare, or they may be plated with a thin layer of another metal, most often tin but sometimes gold , silver or some other material. Tin, gold, and silver are much less prone to oxidation than copper, which may lengthen wire life, and makes soldering easier. Tinning

6364-459: The world's supply in this category. As of 2020, nuclear power stood as the second-largest source of low-carbon energy, making up 26% of the total. Nuclear power facilities are active in 32 countries or regions, and their influence extends beyond these nations through regional transmission grids, especially in Europe. In 2022, nuclear power plants generated 2545 terawatt-hours (TWh) of electricity,

6450-402: The world, and 57 nuclear power reactors under construction. Building a nuclear power plant often spans five to ten years, which can accrue significant financial costs, depending on how the initial investments are financed. Because of this high construction cost and lower operations, maintenance, and fuel costs, nuclear plants are usually used for base load generation, because this maximizes

6536-793: Was gutta-percha (a natural latex ) which was found useful for underwater cables in the 19th century. The first, and still very common, man-made plastic used for cable insulation was polyethylene . This was invented in 1930, but not available outside military use until after World War 2 during which a telegraph cable using it was laid across the English Channel to support troops following D-Day . Cables can be securely fastened and organized, such as by using trunking, cable trays , cable ties or cable lacing . Continuous-flex or flexible cables used in moving applications within cable carriers can be secured using strain relief devices or cable ties. Any current -carrying conductor, including

6622-399: Was 39,930, an increase of 12.3 percent in a decade, according to an analysis of U.S. Census data for msnbc.com. In 2020, the population within 50 miles (80 km) was about 1.4 million, an increase of 43 percent since 2010. Cities within 50 miles include Huntsville (28 miles to city center). According to an NRC study using geological data from 1989 to 2008 which was published in August 2010,

6708-463: Was 90 feet (27 m) wide, 300 feet (91 m) long, and four stories tall) was destroyed in a fire caused by sparks from the electrical cooling fans in the tower hitting the abnormally dry redwood slats within the tower on May 10, 1986. During normal operation, water was kept flowing near-continuously over the redwood slats within the tower, but after close to two months of inactivity, the slats were very dry and extremely flammable. $ 5 million of damage

6794-497: Was done. Cooling tower #3 (which was in the process of being refurbished at the time) was heavily damaged in a fire on May 23, 1996, with about 80% of the tower destroyed. At 11:05 AM on August 19, 2006, Unit 3 was manually scrammed due to loss of both the 3A and 3B Reactor Recirculation pumps. The initial investigation found the Variable Frequency Drive (VFD) microprocessors non-responsive. The root cause of

6880-457: Was estimated to pay for itself in five years. On May 4, 2006, NRC issued a renewed license, adding twenty years to operate through December 20, 2033. Unit 1 generated 9,801 GWh of electricity in 2017, achieving a capacity factor of 101.62%. On March 22, 1975 a fire started when a worker using a candle to search for air leaks accidentally set a temporary cable seal on fire. At Browns Ferry, foamed plastic, covered on both sides with two coats of

6966-441: Was fixed within three hours of when it was discovered and was largely contained within the plant area. The Nuclear Regulatory Commission found that 5 contract workers failed to conduct roving fire watch patrols as required by NRC . As a result, Tennessee Valley Authority was fined $ 140,000 for failing to maintain adequate fire watches in 2015 at Browns Ferry. The 2010 U.S. population within 10 miles (16 km) of Browns Ferry

7052-406: Was highly combustible, and caught fire. Efforts were made by the workers to extinguish the fire at its origin, but they apparently did not recognize that the fire, under the influence of the draft through the penetration, was spreading on the reactor building side of the wall. The extent of the fire in the cable spreading room was limited to a few feet from the penetration; nonetheless, the presence of

7138-512: Was increased to 1,310  MW e (1,256  MW e net ). The uprate for Unit 3 was completed in July 2018, and in January 2019 for Unit 1. The final uprate, for Unit 2, was completed in August 2019, completing the $ 475 million project. The electrical power increase of each unit was facilitated by the maximum operating thermal output of each reactor being increased from 3,458  MW th to 3,952  MW th . The graph represents

7224-477: Was not targeted by sanctions. However, some countries, especially in Europe, scaled back or cancelled planned nuclear power plants that were to be built by Rosatom. Modern nuclear reactor designs have had numerous safety improvements since the first-generation nuclear reactors. A nuclear power plant cannot explode like a nuclear weapon because the fuel for uranium reactors is not enriched enough, and nuclear weapons require precision explosives to force fuel into

7310-598: Was serving 2 million customers within the Tennessee Valley area. On August 16, 2017, the NRC approved TVA's request for a 14.3% uprate of each reactor's output. Each unit's gross electrical output was 1,155  MW e (1,101  MW e net ), but after power uprates during refueling outages in Fall 2018 for Unit 1, Spring 2019 for Unit 2, and Spring 2018 for Unit 3, the gross electrical output for each unit

7396-451: Was subsequently repaired and operated from 1976 through March 3, 1985, when all three Browns Ferry units were shut down for operational and management issues. Starting in 2002, TVA undertook an effort to restore Unit 1 to operational status, spending $ 1.8 billion USD to do so. The NRC approved the restart of Unit 1 on May 15, 2007 and the reactor was brought up to criticality on May 22. During initial testing after restart, on May 24, 2007,

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