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58-640: The Maanshan Nuclear Power Plant ( Chinese : 馬鞍山核能發電廠 ; pinyin : Mǎ'ānshān Hénéng Fādiànchǎng or 核三; Hésān ) is a nuclear power plant located near South Bay , Hengchun , Pingtung County , Taiwan . The plant is Taiwan's third nuclear power plant and second-largest in generation capacity. The expected lifespan of this plant is 60 years. Each unit at Maanshan is a three-loop Westinghouse PWR with three Westinghouse type F steam generators . Each steam generator has 5626 U-bend tubes made of thermally treated Inconel 600 alloy. The power plant can generate 15 TWh of electricity per year. On 7 July 1985

116-412: A dishwasher , washing machine or toilet suddenly shuts off water flow. The result may be heard as a loud bang, repetitive banging (as the shock wave travels back and forth in the plumbing system), or as some shuddering. Other potential causes of water hammer: Steam hammer can occur in steam systems when some of the steam condenses into water in a horizontal section of the piping. The steam forcing

174-614: A hydram to raise water. Through a first reservoir, filled by a channel from the Darro River , water emptied via a large vertical channel into a second reservoir beneath, creating a whirlpool that in turn propelled water through a much smaller pipe up six metres whilst most water drained into a second, slightly larger pipe. In 1772, Englishman John Whitehurst built a hydraulic ram for a home in Cheshire, England. In 1796, French inventor Joseph Michel Montgolfier (1740–1810) built

232-509: A certain extent in South Korea , remain virtually identical to traditional characters, with variations between the two forms largely stylistic. There has historically been a debate on traditional and simplified Chinese characters . Because the simplifications are fairly systematic, it is possible to convert computer-encoded characters between the two sets, with the main issue being ambiguities in simplified representations resulting from

290-402: A damaged support insulator caused one phase to flash to ground. The main transformer trip was followed by main turbine trip and then reactor scram. Following the subsequent repair work, on 8 September 2005 , as the unit was in a hot standby condition, a water hammer occurred in one of the main steam lines. It was determined that condensed water accumulated while the unit was in warm standby with

348-462: A hydraulic ram for his paper mill in Voiron . In French and Italian, the terms for "water hammer" come from the hydraulic ram: coup de bélier (French) and colpo d'ariete (Italian) both mean "blow of the ram". As the 19th century witnessed the installation of municipal water supplies, water hammer became a concern to civil engineers. Water hammer also interested physiologists who were studying

406-479: A loss of power to both 4.16 kV essential busses lost power. Service to these busses was not restored for over two hours, when a swing diesel generator (shared between Units 1 and 2) was brought to service. At the time, this was considered the most notable event in the history of nuclear generation in Taiwan. Neither unit was allowed to restart until the root causes were identified and corrective actions applied, as

464-485: A result, we see that we can reduce the water hammer by: The water hammer effect can be simulated by solving the following partial differential equations. where V is the fluid velocity inside pipe, ρ {\displaystyle \rho } is the fluid density, B is the equivalent bulk modulus, and f is the Darcy–Weisbach friction factor . Column separation is a phenomenon that can occur during

522-411: A resulting shock wave . In domestic plumbing this shock wave is experienced as a loud banging resembling a hammering noise. Water hammer can cause pipelines to break if the pressure is sufficiently high. Air traps or stand pipes (open at the top) are sometimes added as dampers to water systems to absorb the potentially damaging forces caused by the moving water. For example, the water traveling along

580-412: A safety factor of about 5 is recommended: where P 1 is the inlet pressure in psi, V is the flow velocity in ft/ s , t is the valve closing time in seconds, and L is the upstream pipe length in feet. Hence, we can say that the magnitude of the water hammer largely depends upon the time of closure, elastic components of pipe & fluid properties. When a valve with a volumetric flow rate Q

638-463: A second that neglects elasticity but includes a finite time for the valve to close. The pressure profile of the water hammer pulse can be calculated from the Joukowsky equation So for a valve closing instantaneously, the maximal magnitude of the water hammer pulse is where Δ P is the magnitude of the pressure wave (Pa), ρ is the density of the fluid (kg/m ), a 0 is the speed of sound in

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696-501: A single water-hammer event. Most water hammer software packages use the method of characteristics to solve the differential equations involved. This method works well if the wave speed does not vary in time due to either air or gas entrainment in a pipeline. The wave method (WM) is also used in various software packages. WM lets operators analyze large networks efficiently. Many commercial and non-commercial packages are available. Software packages vary in complexity, dependent on

754-400: A tunnel or pipeline to a turbine in a hydroelectric generating station may be slowed suddenly if a valve in the path is closed too quickly. If there is 14 km (8.7 mi) of tunnel of 7.7 m (25 ft) diameter full of water travelling at 3.75 m/s (8.4 mph), that represents approximately 8,000 megajoules (2,200 kWh) of kinetic energy. This energy can be dissipated by

812-462: A turbine blade failure at Maanshan Unit 1 led to a fire and reactor trip. When the blades failed, the resulting turbine imbalance allowed hydrogen and seal oil to escape from the generator. It took approximately 2 hours for the fire to be extinguished, but no systems critical to safe operation and shutdown were affected. The subsequent repairs were so extensive that Unit 1 did not come back on-line for 11 months. The natural frequency of torsional vibration

870-512: A vertical surge shaft into which the water flows which is open at the top. As the water rises up the shaft its kinetic energy is converted into potential energy, avoiding sudden high pressure. At some hydroelectric power stations, such as the Saxon Falls Hydro Power Plant In Michigan , what looks like a water tower is in fact a surge drum . In residential plumbing systems, water hammer may occur when

928-434: A water-hammer event. If the pressure in a pipeline drops below the vapor pressure of the liquid, cavitation will occur (some of the liquid vaporizes, forming a bubble in the pipeline, keeping the pressure close to the vapor pressure). This is most likely to occur at specific locations such as closed ends, high points or knees (changes in pipe slope). When subcooled liquid flows into the space previously occupied by vapor

986-869: Is 産 (also the accepted form in Japan and Korea), while in Hong Kong, Macau and Taiwan the accepted form is 產 (also the accepted form in Vietnamese chữ Nôm ). The PRC tends to print material intended for people in Hong Kong, Macau and Taiwan, and overseas Chinese in traditional characters. For example, versions of the People's Daily are printed in traditional characters, and both People's Daily and Xinhua have traditional character versions of their website available, using Big5 encoding. Mainland companies selling products in Hong Kong, Macau and Taiwan use traditional characters in order to communicate with consumers;

1044-409: Is closed, an excess pressure Δ P is created upstream of the valve, whose value is given by the Joukowsky equation: In this expression: The hydraulic impedance Z of the pipeline determines the magnitude of the water hammer pulse. It is itself defined by where The latter follows from a series of hydraulic concepts: Thus, the equivalent elasticity is the sum of the original elasticities: As

1102-414: Is possible to theoretically explain the 2 millisecond duration 130 bar overpressure peaks with a special 6 equation multiphase thermohydraulic model, similar to RELAP . Steam hammer can be minimized by using sloped pipes and installing steam traps . On turbocharged internal combustion engines , a "gas hammer" can take place when the throttle is closed while the turbocharger is forcing air into

1160-493: The Chinese Commercial News , World News , and United Daily News all use traditional characters, as do some Hong Kong–based magazines such as Yazhou Zhoukan . The Philippine Chinese Daily uses simplified characters. DVDs are usually subtitled using traditional characters, influenced by media from Taiwan as well as by the two countries sharing the same DVD region , 3. With most having immigrated to

1218-501: The Kensiu language . Water hammer This pressure wave can cause major problems, from noise and vibration to pipe rupture or collapse. It is possible to reduce the effects of the water hammer pulses with accumulators , expansion tanks , surge tanks , blowoff valves , and other features. The effects can be avoided by ensuring that no valves will close too quickly with significant flow, but there are many situations that can cause

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1276-640: The Shanghainese -language character U+20C8E 𠲎 CJK UNIFIED IDEOGRAPH-20C8E —a composition of 伐 with the ⼝   'MOUTH' radical—used instead of the Standard Chinese 嗎 ; 吗 . Typefaces often use the initialism TC to signify the use of traditional Chinese characters, as well as SC for simplified Chinese characters . In addition, the Noto, Italy family of typefaces, for example, also provides separate fonts for

1334-507: The "B" phase bushing caused an internal arc after high internal oil pressure caused an access handhole to blow out. Since there was a separate and redundant transformer in place, plant operation was not threatened during the 35 minutes it took to extinguish the fire. The Unit 3 of the power plant was shut down on 16 November 2010 to undergo the EOC-19 outage after running in full cycle continuously, safely and stably for 539 days. One reactor of

1392-555: The People's Republic of China, traditional Chinese characters are standardised according to the Table of Comparison between Standard, Traditional and Variant Chinese Characters . Dictionaries published in mainland China generally show both simplified and their traditional counterparts. There are differences between the accepted traditional forms in mainland China and elsewhere, for example the accepted traditional form of 产 in mainland China

1450-568: The Russian fluid dynamicist Nikolay Yegorovich Zhukovsky (1847–1921), in 1898 by the American civil engineer Joseph Palmer Frizell (1832–1910), and in 1902 by the Italian engineer Lorenzo Allievi (1856–1941). Water flowing through a pipe has momentum. If the moving water is suddenly stopped, such as by closing a valve downstream of the flowing water, the pressure can rise suddenly with

1508-587: The United States during the second half of the 19th century, Chinese Americans have long used traditional characters. When not providing both, US public notices and signs in Chinese are generally written in traditional characters, more often than in simplified characters. In the past, traditional Chinese was most often encoded on computers using the Big5 standard, which favored traditional characters. However,

1566-500: The air into the atmosphere and produce the distinctive hiss-flutter of an aftermarket turbocharger ( blowoff valve ). Water hammers have caused accidents and fatalities, but usually damage is limited to breakage of pipes or appendages. An engineer should always assess the risk of a pipeline burst. Pipelines transporting hazardous liquids or gases warrant special care in design, construction, and operation. Hydroelectric power plants especially must be carefully designed and maintained because

1624-575: The area of contact between the vapor and the liquid increases. This causes the vapor to condense into the liquid reducing the pressure in the vapor space. The liquid on either side of the vapor space is then accelerated into this space by the pressure difference. The collision of the two columns of liquid (or of one liquid column if at a closed end) causes a large and nearly instantaneous rise in pressure. This pressure rise can damage hydraulic machinery , individual pipes and supporting structures. Many repetitions of cavity formation and collapse may occur in

1682-407: The auxiliary feed water system and reactor protection system. Unit 1 was operating at full power on 25 March 2005 when the reactor tripped on low-low water level in steam generator C. Prior to the trip, the high water level alarm in steam generator C was triggered when the water level kept rising and the main feedwater control valve did not respond to manual intervention. When control of the valve

1740-407: The circulatory system. Although it was prefigured in work by Thomas Young , the theory of water hammer is generally considered to have begun in 1883 with the work of German physiologist Johannes von Kries (1853–1928), who was investigating the pulse in blood vessels. However, his findings went unnoticed by civil engineers. Kries's findings were subsequently derived independently in 1898 by

1798-523: The drain valve closed. When that steam line started to supply steam to the turbine, the slug of water was pushed downstream, causing a water hammer and subsequent low steam pressure, resulting in another reactor trip. Maanshan Nuclear Power Plant was affected by the Hengchun earthquake on 26 December 2006 . Because of the vigorous vibration, the alarm at Reactor #2 was activated, forcing the operators to carry out SCRAM immediately. However, Reactor #1

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1856-568: The effect. Rough calculations can be made using the Zhukovsky (Joukowsky) equation, or more accurate ones using the method of characteristics . In the 1st century B.C., Marcus Vitruvius Pollio described the effect of water hammer in lead pipes and stone tubes of the Roman public water supply. Water hammer was exploited before there was even a word for it. The Alhambra , built by Nasrid Sultan Ibn al-Ahmar of Granada beginning 1238, used

1914-427: The engine. There is no shockwave but the pressure can still rapidly increase to damaging levels or cause compressor surge . A pressure relief valve placed before the throttle prevents the air from surging against the throttle body by diverting it elsewhere, thus protecting the turbocharger from pressure damage. This valve can either recirculate the air into the turbocharger's intake (recirculation valve), or it can blow

1972-409: The fluid (m/s), and Δ v is the change in the fluid's velocity (m/s). The pulse comes about due to Newton's laws of motion and the continuity equation applied to the deceleration of a fluid element. As the speed of sound in a fluid is a = B ρ {\displaystyle a={\sqrt {\frac {B}{\rho }}}} , the peak pressure depends on the fluid compressibility if

2030-424: The hafnium neutron absorber and differential thermal expansion (hafnium compared to the stainless steel rod cladding). Taipower later replaced all hafnium-containing rods with a different alloy to resolve the issue. Unit 1 suffered a station blackout on 18 March 2001 when grid instability caused a loss of offsite power and both of the emergency diesel generator trains failed to start. Both units had tripped off-line

2088-493: The inverse is equally true as well. In digital media, many cultural phenomena imported from Hong Kong and Taiwan into mainland China, such as music videos, karaoke videos, subtitled movies, and subtitled dramas, use traditional Chinese characters. In Hong Kong and Macau , traditional characters were retained during the colonial period, while the mainland adopted simplified characters. Simplified characters are contemporaneously used to accommodate immigrants and tourists, often from

2146-448: The liquid water along the pipe forms a " slug " which impacts a valve of pipe fitting, creating a loud hammering noise and high pressure. Vacuum caused by condensation from thermal shock can also cause a steam hammer. Steam hammer or steam condensation induced water hammer (CIWH) was exhaustively investigated both experimentally and theoretically more than a decade ago because it can have radical negative effects in nuclear power plants. It

2204-725: The mainland. The increasing use of simplified characters has led to concern among residents regarding protecting what they see as their local heritage. Taiwan has never adopted simplified characters. The use of simplified characters in government documents and educational settings is discouraged by the government of Taiwan. Nevertheless, with sufficient context simplified characters are likely to be successfully read by those used to traditional characters, especially given some previous exposure. Many simplified characters were previously variants that had long been in some use, with systematic stroke simplifications used in folk handwriting since antiquity. Traditional characters were recognized as

2262-682: The majority of Chinese text in mainland China are simplified characters , there is no legislation prohibiting the use of traditional Chinese characters, and often traditional Chinese characters remain in use for stylistic and commercial purposes, such as in shopfront displays and advertising. Traditional Chinese characters remain ubiquitous on buildings that predate the promulgation of the current simplification scheme, such as former government buildings, religious buildings, educational institutions, and historical monuments. Traditional Chinese characters continue to be used for ceremonial, cultural, scholarly/academic research, and artistic/decorative purposes. In

2320-983: The merging of previously distinct character forms. Many Chinese online newspapers allow users to switch between these character sets. Traditional characters are known by different names throughout the Chinese-speaking world. The government of Taiwan officially refers to traditional Chinese characters as 正體字 ; 正体字 ; zhèngtǐzì ; 'orthodox characters'. This term is also used outside Taiwan to distinguish standard characters, including both simplified, and traditional, from other variants and idiomatic characters . Users of traditional characters elsewhere, as well as those using simplified characters, call traditional characters 繁體字 ; 繁体字 ; fántǐzì ; 'complex characters', 老字 ; lǎozì ; 'old characters', or 全體字 ; 全体字 ; quántǐzì ; 'full characters' to distinguish them from simplified characters. Some argue that since traditional characters are often

2378-677: The official script in Singapore until 1969, when the government officially adopted Simplified characters. Traditional characters still are widely used in contexts such as in baby and corporation names, advertisements, decorations, official documents and in newspapers. The Chinese Filipino community continues to be one of the most conservative in Southeast Asia regarding simplification. Although major public universities teach in simplified characters, many well-established Chinese schools still use traditional characters. Publications such as

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2436-700: The original standard forms, they should not be called 'complex'. Conversely, there is a common objection to the description of traditional characters as 'standard', due to them not being used by a large population of Chinese speakers. Additionally, as the process of Chinese character creation often made many characters more elaborate over time, there is sometimes a hesitation to characterize them as 'traditional'. Some people refer to traditional characters as 'proper characters' ( 正字 ; zhèngzì or 正寫 ; zhèngxiě ) and to simplified characters as 簡筆字 ; 简笔字 ; jiǎnbǐzì ; 'simplified-stroke characters' or 減筆字 ; 减笔字 ; jiǎnbǐzì ; 'reduced-stroke characters', as

2494-420: The pipe, or by a full analysis that includes elasticity. When the time it takes a valve to close is long compared to the propagation time for a pressure wave to travel the length of the pipe, then rigid column theory is appropriate; otherwise considering elasticity may be necessary. Below are two approximations for the peak pressure, one that considers elasticity, but assumes the valve closes instantaneously, and

2552-542: The plant was shut down on 27 April 2015 after its auxiliary step-down transformer was caught on fire. One reactor of the plant was shut down to undergo an overhaul from 9 November 2015 to 7 December 2015 to replace fuel rods and maintain electrical equipment. The overhaul will also include expanding the DC battery capacity for supplying emergency power for safety equipment from 8 hours to 24 hours. The plant cooling water pump experienced malfunction on 24 January 2017 causing

2610-833: The predominant forms. Simplified characters as codified by the People's Republic of China are predominantly used in mainland China , Malaysia, and Singapore. "Traditional" as such is a retronym applied to non-simplified character sets in the wake of widespread use of simplified characters. Traditional characters are commonly used in Taiwan , Hong Kong , and Macau , as well as in most overseas Chinese communities outside of Southeast Asia. As for non-Chinese languages written using Chinese characters, Japanese kanji include many simplified characters known as shinjitai standardized after World War II, sometimes distinct from their simplified Chinese counterparts . Korean hanja , still used to

2668-448: The prior day due to instability in the 345 kV offsite power transmission line, caused by salt-bearing seasonal sea smog. The 4.16 kV essential bus was transferred to the 161 kV offsite power line, but the 161 kV line was lost soon afterwards. The "A" train emergency diesel generator started but was unable to supply power due to a bus grounding fault, and the "B" train diesel generator lost power to its exciter, resulting in

2726-400: The same conditions could have occurred at Unit 2. During the normal full operation of the power plant on 29 January 2005 , Unit 2 reactor scram was initiated followed by a main turbine trip. A universal logic card in the plant's solid-state protection system malfunctioned, erroneously reporting a low-low water level condition in the steam generators. This then caused the actuation of

2784-521: The set of traditional characters is regulated by the Ministry of Education and standardized in the Standard Form of National Characters . These forms were predominant in written Chinese until the middle of the 20th century, when various countries that use Chinese characters began standardizing simplified sets of characters, often with characters that existed before as well-known variants of

2842-439: The shutdown of the plant reactor. A safe half mechanism was activated after the trip. On 23 July 2017 , the second nuclear reactor coolant system of the plant failed and electricity generation was interrupted at 1:10 a.m. The damage was resolved the next day. Traditional Chinese characters Traditional Chinese characters are a standard set of Chinese character forms used to write Chinese languages . In Taiwan ,

2900-583: The traditional character set used in Taiwan ( TC ) and the set used in Hong Kong ( HK ). Most Chinese-language webpages now use Unicode for their text. The World Wide Web Consortium (W3C) recommends the use of the language tag zh-Hant to specify webpage content written with traditional characters. In the Japanese writing system , kyujitai are traditional forms, which were simplified to create shinjitai for standardized Japanese use following World War II. Kyūjitai are mostly congruent with

2958-985: The traditional characters in Chinese, save for minor stylistic variation. Characters that are not included in the jōyō kanji list are generally recommended to be printed in their traditional forms, with a few exceptions. Additionally, there are kokuji , which are kanji wholly created in Japan, rather than originally being borrowed from China. In the Korean writing system , hanja —replaced almost entirely by hangul in South Korea and totally replaced in North Korea —are mostly identical with their traditional counterparts, save minor stylistic variations. As with Japanese, there are autochthonous hanja, known as gukja . Traditional Chinese characters are also used by non-Chinese ethnic groups. The Maniq people living in Thailand and Malaysia use Chinese characters to write

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3016-518: The ubiquitous Unicode standard gives equal weight to simplified and traditional Chinese characters, and has become by far the most popular encoding for Chinese-language text. There are various input method editors (IMEs) available for the input of Chinese characters . Many characters, often dialectical variants, are encoded in Unicode but cannot be inputted using certain IMEs, with one example being

3074-459: The valve is closed abruptly. where When the valve is closed slowly compared to the transit time for a pressure wave to travel the length of the pipe, the elasticity can be neglected, and the phenomenon can be described in terms of inertance or rigid column theory: Assuming constant deceleration of the water column ( dv / dt = v / t ), this gives where: The above formula becomes, for water and with imperial unit, For practical application,

3132-406: The water hammer can cause water pipes to fail catastrophically. The following characteristics may reduce or eliminate water hammer: One of the first to successfully investigate the water hammer problem was the Italian engineer Lorenzo Allievi . Water hammer can be analyzed by two different approaches— rigid column theory , which ignores compressibility of the fluid and elasticity of the walls of

3190-587: The words for simplified and reduced are homophonous in Standard Chinese , both pronounced as jiǎn . The modern shapes of traditional Chinese characters first appeared with the emergence of the clerical script during the Han dynasty c.  200 BCE , with the sets of forms and norms more or less stable since the Southern and Northern dynasties period c.  the 5th century . Although

3248-526: Was 120 Hz, approximately twice that of the electrical frequency, so the resulting resonant vibration led to blade failure. On 24 September 1988 , one control rod assembly was found to be not fully inserted following a reactor trip at Unit 1. Subsequent rod drop tests showed the rod assembly stuck at or above the same not-fully-inserted position, leading to removal and examination of the rod assembly. The examination showed several rods were cracked, which were later determined to result from volumetric growth of

3306-412: Was not affected and remained operational. After the emergency shutdown of Reactor #2, engineers checked the facilities at the plant and no problems had been found. On 12 June 2009 one of the 345 kV startup transformers (which supply station power during refueling outages and reactor startup, and supply backup power to safety-related systems during plant operation) caught fire. Water intrusion into

3364-523: Was switched to a backup system, the valve closed immediately, leading to a low-low water level condition in the steam generator before the valve could be re-opened. It was later determined the primary valve positioner had a loose mechanical connection, resulting in erroneous feedback of valve position. While operating at reduced power in anticipation of typhoon Talim , on 1 September 2005 , the Unit 2 main transformer differential protective relay tripped because

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