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90-646: Ringhals is a nuclear power plant in Sweden . It is situated on the Värö Peninsula (Swedish: Väröhalvön) in Varberg Municipality approximately 65 km south of Gothenburg . With a total power rating of 2,190 MWe , it is the second largest power plant in Sweden. It is owned 70% by Vattenfall and 30% by Uniper SE . The plant has two pressurized water reactors (R3 and R4). A third pressurized water reactor, R2,

180-489: A lathe to "single-point" the threads or by rolling the threads in the solution treated condition (for hardenable alloys) using a screw machine . Inconel 718 can also be roll-threaded after full aging by using induction heat to 700 °C (1,290 °F) without increasing the grain size. Holes with internal threads are made by threadmilling. Internal threads can also be formed using a sinker electrical discharge machining (EDM). Welding of some Inconel alloys (especially

270-588: A nuclear power station ( NPS ), nuclear generating station ( NGS ) or atomic power station ( APS ) 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

360-448: A concept for disposal of high-level radioactive waste called KBS-1, later further developed to KBS-3 . Based upon the KBS-1 concept R3 was, through a highly controversial process including a governmental crisis, granted permission to load fuel on 27 March 1979. The Three Mile Island accident occurred the following day which triggered a referendum in Sweden about nuclear power. The referendum

450-460: 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,

540-442: 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

630-402: 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

720-530: A fee to the Swedish Nuclear Waste Fund, Kärnavfallsfonden (KAF) of 5.2 öre / kWh. This gives an average production cost of 16.0 öre/kWh with and 14.1 öre/kWh without KAF and depreciations. The fees to the Nuclear Waste Fund are intended to finance future expenditures for managing and disposing of spent nuclear fuel and other waste products. Following a number of observations of deficiencies in

810-412: A heat exposure of 850 °C (1,560 °F), and continues to grow after 72 hours of exposure. The most prevalent hardening mechanisms for Inconel alloys are precipitate strengthening and solid solution strengthening . In Inconel alloys, one of the two often dominates. For alloys like Inconel 718, precipitate strengthening is the main strengthening mechanism. The majority of strengthening comes from

900-477: A new government was elected with a clear mandate to phase out nuclear power no later than 1985. Formally this was imposed through a new law, Villkorslagen which required proof of an "absolute safe" method for disposal of spent nuclear fuel before new reactors were allowed to be loaded with fresh nuclear fuel. The law went into force in spring 1977 and hindered the recently completed unit R3 from being loaded with nuclear fuel. The Swedish nuclear industry then developed

990-404: 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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1080-649: 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

1170-479: 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

1260-506: 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

1350-444: 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

1440-625: A result of analysis and observations from the Three Mile Island accident, the Ringhals PWR reactors installed PAR - Passive Autocatalytic hydrogen Recombiners in 2007. Each reactor contains a number of PAR units with catalytic plates, which after a severe core degradation can process the hydrogen emanating from the fuel cladding oxidation within a few hours and hence reduce the risk for violent hydrogen combustion. All European nuclear power plants including Ringhals had to perform stress-tests after

1530-601: A result of thermally induced crystal vacancies (see Arrhenius equation ). Inconel's high temperature strength is developed by solid solution strengthening or precipitation strengthening , depending on the alloy. In age-hardening or precipitation-strengthening varieties, small amounts of niobium combine with nickel to form the intermetallic compound Ni 3 Nb or gamma double prime (γ″). Gamma prime forms small cubic crystals that inhibit slip and creep effectively at elevated temperatures. The formation of gamma-prime crystals increases over time, especially after three hours of

1620-587: 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

1710-413: 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,

1800-427: 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

1890-482: 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

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1980-580: 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,

2070-431: Is a difficult metal to shape and to machine using traditional cold forming techniques due to rapid work hardening . After the first machining pass, work hardening tends to plastically deform either the workpiece or the tool on subsequent passes. For this reason, age-hardened Inconels such as 718 are typically machined using an aggressive but slow cut with a hard tool, minimizing the number of passes required. Alternatively,

2160-410: 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. Inconel Inconel alloys are typically used in high temperature applications. Common trade names for various Inconel alloys include: The Inconel family of alloys

2250-481: Is also used in the turbo system of the 3rd generation Mazda RX7 , and the exhaust systems of high powered Wankel engine and Norton motorcycles where exhaust temperatures reach more than 1,000 °C (1,830 °F). Inconel is increasingly used in the boilers of waste incinerators . The Joint European Torus and DIII-D tokamaks' vacuum vessels are made of Inconel. Inconel 718 is commonly used for cryogenic storage tanks, downhole shafts, wellhead parts, and in

2340-520: 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

2430-503: 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

2520-443: Is coherent and has an FCC structure, like the γ matrix; The γ' phase is much less prevalent than γ″. The volume fraction of the γ″ and γ' phases are approximately 15% and 4% after precipitation, respectively. Because of the coherency between the γ matrix and the γ' and γ″ precipitates, strain fields exist that obstruct the motion of dislocations. The prevalence of carbides with MX(Nb, Ti)(C, N) compositions also helps to strengthen

2610-512: Is common in gas turbine blades, seals, and combustors, as well as turbocharger rotors and seals, electric submersible well pump motor shafts, high temperature fasteners, chemical processing and pressure vessels , heat exchanger tubing, steam generators and core components in nuclear pressurized water reactors , natural gas processing with contaminants such as H 2 S and CO 2 , firearm sound suppressor blast baffles, and Formula One , NASCAR , NHRA , and APR, LLC exhaust systems. It

2700-431: 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

2790-447: Is not required to produce any active power during the contract period, but the generators will be available for control of voltage and reactive power in a situation with large electricity generation in the north of Sweden and large consumption in the south. On 31 December 2020 the R1 reactor was permanently shut down. Nuclear power plant A nuclear power plant ( NPP ), also known as

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2880-429: 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

2970-486: 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

3060-491: 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

3150-562: The Swedish Radiation Safety Authority stated that in case that the reactors were to be shut down when they were originally planned to be closed, i.e. around 2025, they could be operated without additional upgrades after 2020. In connection with the decision to close Ringhals 1 and Ringhals 2 in 2015, a write-down of the total fixed value of these was made in the annual report for 2015 of SEK 10,863 million. The production costs for all reactors at Ringhals can be obtained from

3240-656: 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

3330-631: 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

3420-424: 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

3510-485: 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

3600-436: The 2040s. In January 2016, Vattenfall announced that all its Swedish nuclear power plants, including the newer reactors, were operating at a loss due to low electricity prices and Sweden's nuclear power tax ("effektskatt"). It warned that it may be forced to shut all the nuclear plants down, and argued that the nuclear output tax, which constituted over one third of the price, should be scrapped. Through an agreement 10 June 2016

3690-459: The 2040s. On 30 December 2019, the R2 reactor was permanently shut down. In June 2020, a contract was signed between Svenska kraftnät (Swedish national grid operator) and Ringhals AB that would grant Ringhals an allowance of 300 million SEK (approximately 30 million US dollars) to keep R1 reactor connected to the grid from 1 July to 15 September 2020 in order to increase grid stability. Strictly Ringhals 1

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3780-559: 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

3870-638: The FCVS can relieve the containment pressure with limited releases of radioactivity. The systems went into operation at Barsebäck in 1985 and for the other plants in 1989. As a result of the Barsebäck strainer incident in 1992 the recirculation strainer capacity was significantly increased for R1 in 1992 and R2 in 1994. Units R3 and R4 made similar upgrades in 2005. During the 2005-2015 period, significant improvements were made regarding fire separation, redundancy and diversification of various safety systems, particularly for

3960-466: The Fukushima accident 2011, where consequences of certain beyond-design-events should be assessed. The availability of FCVS - Filtered Containment Venting System, ICSS - Independent Containment Spray System and PAR - Passive Autocatalytic hydrogen Recombiners, turned out to be valuable capabilities in these beyond-design-events and no immediate plant modifications were proposed as a post-Fukushima-response. On

4050-527: The Inconel trademark were acquired in 1998 by Special Metals Corporation . Inconel alloys vary widely in their compositions, but all are predominantly nickel, with chromium as the second element. When heated, Inconel forms a thick and stable passivating oxide layer protecting the surface from further attack. Inconel retains strength over a wide temperature range, attractive for high-temperature applications where aluminium and steel would succumb to creep as

4140-477: The Laves phase can exhaust the matrix of these elements, ultimately making precipitate and solid-solution strengthening more difficult. For alloys like Inconel 625, solid-solution hardening is the main strengthening mechanism. Elements like Mo are important in this process. Nb and Ta can also contribute to solid solution strengthening to a lesser extent. In solid solution strengthening, Mo atoms are substituted into

4230-596: The aerospace industry -- where it has become a prime candidate material for constructing heat resistant turbines. Rolled Inconel was frequently used as the recording medium by engraving in black box recorders on aircraft. Alternatives to the use of Inconel in chemical applications such as scrubbers, columns, reactors, and pipes are Hastelloy , perfluoroalkoxy (PFA) lined carbon steel or fiber reinforced plastic . Alloys of Inconel include: In age hardening or precipitation strengthening varieties, alloying additions of aluminum and titanium combine with nickel to form

4320-493: The annual report for 2018 which shows a cost for goods sold of SEK 6,289 million. If all other costs including administrative costs and R&D are added with no adjustments for revenue for some of these costs the cost is SEK 6,379 million with a depreciation of SEK 576 million, i.e. the cost excluding these was SEK 5,803 million. The production of electricity was 30.1 TWh, which gives a production cost of 21.2 öre/kWh including depreciation and 19.3 öre/kWh without. This amount includes

4410-552: 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

4500-828: The continuing operation of these reactors, which it argues were shown to be unsafe in European stress tests." The inner perimeter fence (with barbed wire, CCTV-surveillance, "no-go" zone etc.) around the reactors was not scaled. On 30 July 2018, Ringhals-2 was taken offline during the 2018 European heat wave , since the sea water temperature exceeded the design limit 25 DegC. The reactor was restarted on 3 August. The other reactors R1, R3 and R4 were not affected since they are licensed for slightly higher temperatures. In October 2015, Vattenfall decided to close down Ringhals 1 by 2020 and Ringhals 2 by 2019 due to their declining profitability, instead of, as previously announced, around 2025. Ringhals 3 and 4 are still expected to continue in service until

4590-508: The contrary Ringhals made significant upgrades in the emergency preparedness organization in the size, education and training of the staffing, and in the independence and durability (power supply, communications, etc.) for certain systems and buildings. In December 2014, the Swedish regulator required that all Swedish reactors should be equipped with an Independent Core Cooling System - ICCS - before 31 December 2020. The system should be able to cool

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4680-485: 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

4770-424: 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

4860-458: 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

4950-534: 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,

5040-402: 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

5130-775: 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

5220-411: 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

5310-513: 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 ,

5400-432: The gamma prime precipitation hardened family; e.g., Waspaloy and X-750) can be difficult due to cracking and microstructural segregation of alloying elements in the heat-affected zone . However, several alloys such as 625 and 718 have been designed to overcome these problems. The most common welding methods are gas tungsten arc welding and electron-beam welding . Inconel is often encountered in extreme environments. It

5490-406: 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

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5580-426: 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

5670-621: The loss of coherency strengthening, making for a weaker material. That being said, in appropriate quantities, the δ phase is responsible for grain boundary pinning and strengthening. Another common phase in Inconel alloys is the Laves intermetallic phase. Its compositions are (Ni, Cr, Fe) x (Nb, Mo, Ti) y and Ni y Nb, it is brittle, and its presence can be detrimental to the mechanical behavior of Inconel alloys. Sites with large amounts of Laves phase are prone to crack propagation because of their higher potential for stress concentration. Additionally, due to its high Nb, Mo, and Ti content,

5760-431: The major part of the nuclear power tax was removed on 1 July 2017, but combined with prolonged and enhanced support for renewable electricity production. The removal of the nuclear power tax corresponds to a tax reduction of approximately 7 öre or 0.007 EUR/kWh which corresponds to around 25% of the generating cost. This is a significant cost reduction and has been important for Vattenfall's decision to operate R3 and R4 until

5850-438: The majority of the machining can be performed with the workpiece in a "solutionized" form, with only the final steps being performed after age hardening. However some claim that Inconel can be machined extremely quickly with very fast spindle speeds using a multifluted ceramic tool with small width of cut at high feed rates as this causes localized heating and softening in front of the flute. External threads are machined using

5940-452: The material. For precipitate strengthening, elements like niobium, titanium, and tantalum play a crucial role. Because the γ″ phase is metastable, over-aging can result in the transformation of γ″ phase precipitates to delta (δ) phase precipitates, their stable counterparts. The δ phase has an orthorhombic structure, a Ni 3 (Nb, Mo, Ti) composition, and is incoherent. As a result, the transformation of γ″ to δ in Inconel alloys leads to

6030-586: 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

6120-473: 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

6210-510: The older plants R1 and R2 . The original steam generators for the Ringhals PWRs had tubes of Inconel-600 and details in the construction that made them prone to cracks and corrosion. This triggered huge efforts for inspection, maintenance and repair. Although designed for 40 years of operation, both unit R2 and R3 replaced their steam generators after 14 years, i.e. 1989 and 1995. Unit R4, starting later, could take advantage of being aware of

6300-498: The presence of gamma double prime (γ″) precipitates. Inconel alloys have a γ matrix phase with an FCC structure. γ″ precipitates are made of Ni and Nb, specifically with a Ni 3 Nb composition. These precipitates are fine, coherent, disk-shaped, intermetallic particles with a tetragonal structure. Secondary precipitate strengthening comes from gamma prime (γ') precipitates. The γ' phase can appear in multiple compositions such as Ni 3 (Al, Ti). The precipitate phase

6390-448: The problems, and due to high attention to water chemistry and maintenance efforts the R4 steam generators were replaced in 2011 after 28 years of operation. All the new steam generators have tubes of Inconel-690 and improved design, and have had very few problems and high availability. This is especially true for R2 which, as of 2017, had been operating 28 years with the new steam generators. As

6480-474: 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

6570-424: The public and political opinion in Sweden was fairly positive to nuclear power. One reason was that until 1970 nearly all electricity came from a continuously increasing exploitation of the large and wild rivers in the north of Sweden, and the diminishing number of remaining, unexploited rivers created fierce opposition against further hydro power development. Opinion changed and in the parliamentary election of 1976

6660-427: 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,

6750-550: The reactor during 72 hours without any supply of water, power, fuel or other consumables, and should survive external events (seismic events, hard weather etc.) with an estimated probability of exceedance of 10/yr. The requirements are influenced by the so-called "Forsmark-event" 25 July 2006 and the Fukushima accident . Design of and preparations for ICCS is (2017) already underway for R3 and R4, but will not be made for R1 and R2 since they were planned to be shut down before 2021. However,

6840-540: 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

6930-464: The safety culture since 2005, the Swedish Radiation Safety Authority decided in 2009 to put Ringhals under increased surveillance. Ringhals made certain efforts in order to improve traceability and transparency in decision making, internal audits and analyses of incidents and mistakes. The regulator acknowledged the improvements, and the increased surveillance was waived for 2013. In 2012 a small quantity of explosives, although without any firing device,

7020-407: 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

7110-548: The start-up of the sister-plant R3, and started commercial operation on 21 November 1983. As a result of the Three Mile Island accident in 1979, all Swedish reactors were required to install FCVS - Filtered Containment Venting System - and ICSS - Independent Containment Spray System . In case of an accident with core degradation and loss of all cooling systems the ICSS can still limit the containment pressure, and should this fail

7200-693: 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,

7290-487: 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

7380-477: 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

7470-455: 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,

7560-402: 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

7650-553: The γ matrix of Inconel alloys. Because Mo atoms have a significantly larger radius than those of Ni (209 pm and 163 pm, respectively), the substitution creates strain fields in the crystal lattice, which hinder the motion of dislocations, ultimately strengthening the material. The combination of elemental composition and strengthening mechanisms is why Inconel alloys can maintain their favorable mechanical and physical properties, such as high strength and fatigue resistance, at elevated temperatures, specifically those up to 650°C. Inconel

7740-612: Was first developed before December 1932, when its trademark was registered by the US company International Nickel Company of Delaware and New York. A significant early use was found in support of the development of the Whittle jet engine, during the 1940s by research teams at Henry Wiggin & Co of Hereford, England a subsidiary of the Mond Nickel Company , which merged with Inco in 1928. The Hereford Works and its properties including

7830-480: Was found during a routine check underneath a truck at the plant. For a short time all nuclear power plants in Sweden increased their alert level, but no more explosives were found, and no-one could be tied to the discovery. In October 2012, 20 anti-nuclear Greenpeace activists scaled the outer perimeter standard industrial fence, and there was also an incursion at Forsmark nuclear power plant. Greenpeace said that its non-violent actions were "intended to protest against

7920-458: Was held on 23 March 1980 and the result was interpreted as a "yes" to completion of construction and operation of the whole Swedish nuclear program with 12 reactors. Hence R3 could be loaded with fuel and started commercial operation on 9 September 1981, more than four years after essentially completed the construction phase in 1977. R4 was also somewhat delayed due to the referendum but also due to remediation of some technical problems identified at

8010-477: 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

8100-557: Was permanently shut down in 2019. On 31 December 2020 the R1 boiling water reactor was also permanently shut down. Planning and land procurement of the site started in 1965. Two reactors were ordered in 1968: one boiling water reactor from ABB-ATOM (R1) and one pressurized water reactor from Westinghouse (R2). Construction work started in 1969; commercial operation started for R2 in 1975, and for R1 in 1976. Two more pressurized water reactors, R3 and R4, were ordered from Westinghouse in 1971 and construction work started in 1972. So far

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