117-549: The EPR is a Generation III+ pressurised water reactor design. It has been designed and developed mainly by Framatome (part of Areva between 2001 and 2017) and Électricité de France (EDF) in France, and by Siemens in Germany. In Europe this reactor design was called European Pressurised Reactor , and the internationalised name was Evolutionary Power Reactor , but is now simply named EPR . The first operational EPR unit
234-408: A nuclear renaissance suggesting that Gen III+ designs should solve three key problems: safety, cost and buildability. Construction costs of US$ 1,000/kW were forecast, a level that would make nuclear competitive with gas, and construction times of four years or less were expected. However, these estimates proved over-optimistic. A notable improvement of Gen III+ systems over second-generation designs
351-580: A 200-tonne core catcher in the VVER reactor as the first large piece of equipment in the reactor building of Rooppur 1 , describing it as "a unique protection system". In 2017, Rosatom has started commercial operations of the NVNPP-2 Unit 1 VVER-1200 reactor in central Russia, marking the world's first full start-up of a generation III+ reactor. The first Generation III reactors were built in Japan, in
468-503: A LOC incident. However, when a team was sent to investigate the status of the RCIC of unit 2 the following morning (02:55), they confirmed that the RCIC was operating with the PCV pressure well below design limits. Based on this information, efforts were focused on unit 1. However, the condensate storage tank from which the RCIC draws water was nearly depleted by the early morning, and so the RCIC
585-403: A closed coolant loop from the pressure vessel with a heat exchanger in a dedicated condenser tank. Steam would be forced into the heat exchanger by the reactor pressure, and the condensed coolant would be fed back into the vessel by gravity. Each reactor was initially designed to be equipped with two redundant ICs which were each capable of cooling the reactor for at least 8 hours (at which point,
702-405: A closed-loop system which draws coolant from the suppression chamber (SC) instead of the storage tank, should the storage tank be depleted. Although this system could function autonomously without an external energy source (besides the steam from the reactor), direct current (DC) was needed to remotely control it and receive parameters and indications and alternating current (AC) was required to power
819-554: A delay of fourteen years. The second EPR unit to start construction, at Flamanville in France, also suffered a more than decade-long delay in its commissioning (from 2012 to 2024). Two units at Hinkley Point in the United Kingdom received final approval in September 2016; the first unit was expected to begin operating in 2027, but was subsequently delayed to around 2030. EDF has acknowledged severe difficulties in building
936-562: A design maximum core damage frequency of 6.1 × 10 per station per year and a gross power output of 1770 MWe for a mains frequency of 50 Hz. The version submitted to the U.S. NRC has a power output of 1600 MWe (net). In 2013, EDF acknowledged the difficulties it was having building the EPR design, with its head of production and engineering, Hervé Machenaud, saying EDF had lost its dominant international position in design and construction of nuclear power stations. Machenaud indicated EDF
1053-425: A mains frequency of 50 Hz. It has 4 coolant loops with 1 steam generator per loop. There are concrete walls between loops and the hot and cold parts of each loop to protect against failures. Besides the double layer containment there is a concrete wall surrounding the primary system components inside the containment. The EPR design has several active and passive protection measures against accidents: The EPR has
1170-452: A new model EPR] is neither a priority or a plan. Right now the priority is to develop renewable energy and to reduce the share of nuclear." The industry-government plan for 2019–2022 included work on "a new version of the EPR". In July 2019, the French nuclear safety authority ASN issued an opinion on the safety of an outlined new EPR model (EPR2) design. It found that general safety was on
1287-491: A number of iterations. The 1994 conceptual design had a power output of 1450 MWe, the same as the Framatome N4, but using Siemens Konvoi derived instrumentation and also including a new core catcher safety system. By 1995, there was concern over excessive cost per MW, and output was raised to 1800 MWe in the 1997 design, though this was subsequently reduced to 1650 MWe (net) in the final certified design, for
SECTION 10
#17327866100331404-528: A number of safety-related design and manufacturing 'deficiencies'. In August 2007, a further construction delay of up to a year was reported associated with construction problems in reinforcing the reactor building to withstand an aeroplane crash, and the timely supply of adequate documentation to the Finnish authorities. In September 2007, TVO reported the construction delay as "at least two years" and costs more than 25% over budget. Cost estimates by analysts for
1521-416: A suspension of concrete pouring on the site. A month later, concreting work resumed after ASN accepted EDF's corrective action plan, which included external oversight checks. In May 2009, Stephen Thomas reported that after 18 months of construction, and after a series of quality control problems, the project is "more than 20 percent over budget and EDF is struggling to keep it on schedule". In August 2010,
1638-613: A whole are safer than older reactors. Edwin Lyman , a senior staff scientist at the Union of Concerned Scientists , has challenged specific cost-saving design choices made for two Generation III reactors, both the AP1000 and ESBWR . Lyman, John Ma (a senior structural engineer at the NRC), and Arnold Gundersen (an anti-nuclear consultant) are concerned about what they perceive as weaknesses in
1755-848: Is arbitrary, few Gen III reactors have reached the commercial stage as of 2022. The Generation IV International Forum calls Gen IV reactors "revolutionary designs". These are concepts for which no concrete prognoses for realization existed at the time. The improvements in reactor technology in third generation reactors are intended to result in a longer operational life (designed for 60 years of operation, extendable to 100+ years of operation prior to complete overhaul and reactor pressure vessel replacement) compared with currently used Generation II reactors (designed for 40 years of operation, extendable to 60+ years of operation prior to complete overhaul and pressure vessel replacement). The core damage frequencies for these reactors are designed to be lower than for Generation II reactors – 60 core damage events for
1872-412: Is led by Taishan Nuclear Power Joint Venture Co. (TNPJVC), a joint venture founded by CGN (51% ownership stake), EDF (30%), and Chinese utility Guangdong Energy Group (19%), also known as Yuedian. Companies involved in supplying equipment to Taishan Unit 1 include Framatome, which manufactured the steam generators and pressurizer in France, and China’s Dongfang Electric Corp. (DEC), which manufactured
1989-424: Is no longer able to finance EPR2 construction on its own, so financing and profitability issues need to be resolved. The audit office requires that EDF ensure the financing and profitability of EPR2 before constructing any in France. In January 2022, junior environment minister Bérangère Abba said that plans for new EPR2 reactors, to be operational between 2035 and 2037, should be submitted around 2023. The decision
2106-811: Is regarded as the worst nuclear incident since the Chernobyl disaster in 1986, which was also rated a seven on the International Nuclear Event Scale. According to the United Nations Scientific Committee on the Effects of Atomic Radiation , "no adverse health effects among Fukushima residents have been documented that are directly attributable to radiation exposure from the Fukushima Daiichi nuclear plant accident". Insurance compensation
2223-596: Is that, unlike the first EPR design, the EPR2 design does not allow access to the reactor building for maintenance during reactor operation, which simplifies the design of the reactor building. In 2020, French Energy Minister Élisabeth Borne announced the French government would not decide on the construction of any new reactors until the much delayed Flamanville 3 started operation after 2022. EDF had estimated that building six EPR2 nuclear reactors would cost at least €46 billion. A Court of Audit report concluded that EDF
2340-485: Is the evolutionary descendant of the Framatome N4 and Siemens Power Generation Division " Konvoi [ de ] " reactors. Siemens ceased its nuclear activities in 2011. The EPR was designed to use uranium more efficiently than older Generation II reactors , using approximately 17% less uranium per kilowatt-hour of electricity generated than these older reactor technologies. The design has gone through
2457-488: Is the incorporation in some designs of passive safety features that do not require active controls or operator intervention but instead rely on gravity or natural convection to mitigate the impact of abnormal events. Generation III+ reactors incorporate extra safety features to avoid the kind of disaster suffered at Fukushima in 2011. Generation III+ designs, passive safety, also known as passive cooling, requires no sustained operator action or electronic feedback to shut down
SECTION 20
#17327866100332574-624: The EPR as the only new reactor design under consideration in the United States that "...appears to have the potential to be significantly safer and more secure against attack than today's reactors." There have also been issues in fabricating the precision parts necessary to maintain safe operation of these reactors, with cost overruns, broken parts, and extremely fine steel tolerances causing issues with new reactors under construction in France at
2691-763: The European Pressurized Reactor (EPR) and 3 core damage events for the Economic Simplified Boiling Water Reactor (ESBWR) per 100 million reactor-years are significantly lower than the 1,000 core damage events per 100 million reactor-years for BWR/4 Generation II reactors. The third generation EPR reactor was also designed to use uranium more efficiently than older Generation II reactors, using approximately 17% less per unit of electricity generated than these older reactor technologies. An independent analysis conducted by environmental scientist Barry Brook on
2808-564: The Flamanville Nuclear Power Plant . Fukushima Daiichi nuclear disaster The Fukushima nuclear accident was a major nuclear accident at the Fukushima Daiichi nuclear power plant in Ōkuma, Fukushima , Japan which began on 11 March 2011. The proximate cause of the accident was the 2011 Tōhoku earthquake and tsunami , which resulted in electrical grid failure and damaged nearly all of
2925-546: The Generation IV International Forum (GIF). The first Generation III reactors to begin operation were Kashiwazaki 6 and 7 advanced boiling water reactors (ABWRs) in 1996 and 1997. From 2012, both have been shut down due to a less permissive political environment in the wake of the Fukushima nuclear accident . Due to the prolonged period of stagnation in the construction of new reactors and
3042-879: The Taishan Nuclear Power Station (first grid connection on 2018-06-29) and a Westinghouse AP1000 reactor at the Sanmen Nuclear Power Station (first grid connection on 2018-06-30) in China. In the United States, reactor designs are certified by the Nuclear Regulatory Commission (NRC). As of August 2020 , the commission has approved seven new designs, and is considering one more design as well as renewal of an expired certification. Proponents of nuclear power and some who have historically been critical have acknowledged that third generation reactors as
3159-476: The disposal of treated wastewater once used to cool the reactor , resulting in numerous protests in neighboring countries. The Fukushima Daiichi Nuclear Power Plant consisted of six General Electric (GE) light water boiling water reactors (BWRs). Unit 1 was a GE type 3 BWR. Units 2–5 were type 4. Unit 6 was a type 5. At the time of the Tōhoku earthquake on 11 March 2011 , units 1–3 were operating. However,
3276-456: The reactor pressure vessel (RPV) and embedded itself into the concrete at the base of the PCV. Although at the time it was difficult to determine how far the fuel had eroded and diffused into the concrete, it was estimated that the fuel remained within the PCV. Computer simulations, from 2013, suggest "the melted fuel in Unit 1, whose core damage was the most extensive, has breached the bottom of
3393-500: The spent fuel pools of all units still required cooling. Many of the internal components and fuel assembly cladding are made from a zirconium alloy (Zircaloy) for its low neutron cross section . At normal operating temperatures (~300 °C (572 °F)), it is inert. However, above 1,200 °C (2,190 °F), Zircaloy can be oxidized by steam to form hydrogen gas or by uranium dioxide to form uranium metal . Both of these reactions are exothermic . In combination with
3510-492: The 13 EDGs, 10 were water-cooled and placed in the basements about 7–8 m below the ground level. The coolant water for the EDGs was carried by several seawater pumps placed on the shoreline which also provide water for the main condenser. These components were unhoused and only protected by the seawall. The other three EDGs were air-cooled and were connected to units 2, 4, and 6. The air-cooled EDGs for units 2 and 4 were placed on
3627-573: The 20th. Unit 6 was not operating, and its decay heat was low. All but one EDG was disabled by the tsunami, allowing unit 6 to retain AC-powered safety functions throughout the incident. However, because the RHR was damaged, workers activated the make-up water condensate system to maintain the reactor water level until the RHR was restored on the 20th. Cold shutdown was achieved on the 20th, less than an hour after unit 5. On 21 March, temperatures in
EPR (nuclear reactor) - Misplaced Pages Continue
3744-686: The Arabelle turbine in the engine room. That turbine was designed and licensed by General Electric. Other equipment suppliers for Unit 1 include Mitsubishi (reactor vessel); Škoda, a Czech company (core internals); and France’s Jeumont Electric, which along with DEC provided primary pumps. In April 2020, Framatome signed a long-term service contract with TNPJVC to support operations of the two EPRs. This contract covers nuclear plant outage and maintenance work, including spare parts supply and engineering services for eight years. In June 2021, higher than expected concentrations of radioactive gases were detected in
3861-721: The EPR design. In September 2015, EDF stated that the design of a "New Model" EPR (later named EPR2 ) was being worked on and that it would be easier and cheaper to build. The main objectives of the third generation EPR design are increased safety while providing enhanced economic competitiveness through improvements to previous pressurised water reactor designs scaled up to an electrical power output of around 1650 MWe (net) with thermal power of 4500 MW. The reactor can use 5% enriched uranium oxide fuel, reprocessed uranium fuel or 100% mixed uranium plutonium oxide fuel, clad in Areva's M5 variant of zirconium alloy . The EPR
3978-844: The EPR2 is being developed using three instead of four coolant loops generating 1200 MWe net, the EPR1200, intended for export. In February 2023, regulator ASN issued a positive opinion on the safety features of the EPR1200. Construction of the Olkiluoto 3 power station in Finland began in August 2005. The station has an electrical power output of 1600 MWe (net). The construction was a joint effort of French Areva and German Siemens AG through their common subsidiary Areva NP, for Finnish operator TVO . Siemens ceased nuclear activities in 2011. Initial cost estimates were about €3.7 billion, but
4095-462: The FP injection port was hidden under debris. The next morning (12 March, 04:00), approximately 12 hours after the loss of power, freshwater injection into the reactor vessel began, later replaced by a water line at 09:15 leading directly from the water storage tank to the injection port to allow for continuous operation (the fire engine had to be periodically refilled). This continued into the afternoon until
4212-514: The Finnish approach to approving technical documentation and designs. In December 2006, TVO announced construction was about 18 months behind schedule so completion was now expected 2010–11, and there were reports that Areva was preparing to take a €500 million charge on its accounts for the delay. At the end of June 2007, it was reported that Säteilyturvakeskus (STUK), the Finnish Radiation and Nuclear Safety Authority, had found
4329-403: The French nuclear regulator ASN that anomalies had been detected in the reactor vessel steel, causing "lower than expected mechanical toughness values". Further tests are underway. In July 2015 The Daily Telegraph reported that Areva had been aware of this problem since 2006. In June 2015, multiple faults in cooling system safety valves were discovered by ASN. In September 2015, EDF announced that
4446-487: The Fukushima coast. In response to the station blackout during the initial hours of the accident and the ongoing uncertainty regarding the cooling status of units 1 and 2, a 2 km radius evacuation of 1,900 residents was ordered at 20:50. However, due to difficulty coordinating with the national government, a 3 km evacuation order of ~6,000 residents and a 10 km shelter-in-place order for 45,000 residents
4563-523: The HPCI and RCIC systems, but both failed to restart. Following this loss of cooling, workers established a water line from the valve pit to inject seawater into the reactor alongside unit 2. However, water could not be injected due to RPV pressures exceeding the pump capability. Similarly, preparations were also made to vent the unit 3 PCV, but PCV pressure was not sufficient to burst the rupture disk. Later that morning (9:08), workers were able to depressurize
4680-539: The HPCI system showed signs of malfunction. The HPCI isolation valve failed to activate automatically upon achieving a certain pressure. In response, the workers switched off HPCI and began injection of water via the lower-pressure firefighting equipment. However, the workers found that the SRVs did not operate to relieve pressure from the reactor vessel to allow water injection by the DDFP. In response, workers attempted to restart
4797-435: The PCV was completed later that afternoon at 14:00. At the same time, pressure in the reactor vessel had been decreasing to equalize with the PCV, and the workers prepared to inject water into the reactor vessel using the DDFP once the pressure had decreased below the 0.8 MPa limit. Unfortunately, the DDFP was found to be inoperable and a fire truck had to be connected to the FP system. This process took about 4 hours, as
EPR (nuclear reactor) - Misplaced Pages Continue
4914-473: The RCIC system failed. In response, the high-pressure coolant injection (HPCI) system was activated to alleviate the lack of cooling while workers continued to attempt to restart the RCIC. Additionally, the FP system was used to spray the PCV (mainly the SC) with water in order to slow the climbing temperatures and pressures of the PCV. On the morning of the 13th (02:42), after DC power was restored by new batteries,
5031-422: The RCIC system was continuing to cool the reactor. However, knowing that their DC supply was limited, the workers managed to extend the backup DC supply to about 2 days by disconnecting nonessential equipment, until replacement batteries were brought from a neighboring power station on the morning of the 13th (with 7 hours between loss and restoration of DC power). At 11:36 the next day, after 20.5 hours of operation,
5148-436: The atmosphere, those which remain in a gaseous phase will simply be diluted by the atmosphere, but some which precipitate will eventually settle on land or in the ocean. Approximately 40–80% of the atmospheric caesium-137 was deposited in the ocean. Thus, the majority (90~99%) of the radionuclides which are deposited are isotopes of iodine and caesium, with a small portion of tellurium , which are almost fully vaporized out of
5265-410: The blackout, the RCIC was functioning as designed without the need for operator intervention. The safety relief valves (SRVs) would intermittently release steam directly into the PCV suppression torus at its design pressure and the RCIC properly replenished lost coolant. However, following the total blackout of Unit 2, the plant operators (similar to Unit 1) assumed the worst-case scenario and prepared for
5382-540: The commissioning schedule would be affected. The feedwater pumps are larger than in other nuclear reactors. Olkiluoto 3 started regular electricity production in April 2023. In 2006, Areva took part in the first bidding process for the construction of four new nuclear reactors in China, together with Toshiba-owned Westinghouse and Russian Atomstroyexport . However Areva lost this bid in favour of Westinghouse's AP1000 reactors, in part because of Areva's refusal to transfer
5499-459: The condenser tank would have to be refilled). However, it was possible for the IC system to cool the reactor too rapidly shortly after shutdown which could result in undesirable thermal stress on the containment structures. To avoid this, the protocol called for reactor operators to manually open and close the condenser loop using electrically operated control valves. After the construction of Unit 1,
5616-708: The contaminated waters far into the Pacific Ocean, dispersing the radioactivity. As of late 2011, measurements of both the seawater and the coastal sediments suggested that the consequences for marine life would be minor. Significant pollution along the coast near the plant might persist, because of the continuing arrival of radioactive material transported to the sea by surface water crossing contaminated soil. The possible presence of other radioactive substances, such as strontium-90 or plutonium , had not been sufficiently studied. Recent measurements show persistent contamination of some marine species (mostly fish) caught along
5733-418: The continued (albeit declining) popularity of Generation II/II+ designs in new construction, relatively few third generation reactors have been built. The older Gen II reactors comprise the vast majority of current nuclear reactors. Gen III reactors are so-called advanced light-water reactors (LWRs). Gen III+ reactors are labeled as "evolutionary designs". Though the distinction between Gen II and III reactors
5850-431: The core due to their high vapor pressure. The remaining fraction of deposited radionuclides are of less volatile elements such as barium , antimony , and niobium , of which less than a percent is evaporated from the fuel. In addition to atmospheric deposition, there was also a significant quantity of direct releases into groundwater (and eventually the ocean) through leaks of coolant which had been in direct contact with
5967-399: The critical parts of the reactor was found. In 2006, the design of the reactors was reevaluated with new standards requiring the reactors to withstand accelerations ranging up to 450 Gal. In the event of an emergency, operators planned to pump water into the reactors to keep them cool. This would inevitably create steam which should not be very radioactive because the fuel would still be in
SECTION 50
#17327866100336084-426: The electrical buildings can be completely prefabricated. The fourth emergency/safety cooling system/train of the reactor is removed which means maintenance can only be performed when the plant is shut down. This train was added at the request of German electricians in the original EPR design to allow for on-power maintenance. The core catcher has been modified. It has a net power output of 1670 MWe. A smaller variant of
6201-590: The estimated costs had escalated to €10.5 billion, and the start-up of the reactor was delayed to the fourth quarter of 2018. Generation III reactor Generation III reactors , or Gen III reactors , are a class of nuclear reactors designed to succeed Generation II reactors, incorporating evolutionary improvements in design. These include improved fuel technology , higher thermal efficiency , significantly enhanced safety systems (including passive nuclear safety ), and standardized designs intended to reduce maintenance and capital costs. They are promoted by
6318-550: The estimated costs had escalated to €8.5 billion. Also in December 2012, the Italian power company Enel announced it was relinquishing its 12.5% stake in the project, and five future EPRs, so would be reimbursed its project stake of €613 million, plus interest. In November 2014, EDF announced that completion of construction was delayed to 2017, due to delays in component delivery by Areva. In April 2015, Areva informed
6435-473: The exothermic reaction of boron carbide with stainless steel , these reactions can contribute to the overheating of a reactor. In the event of an emergency, reactor pressure vessels (RPV) are automatically isolated from the turbines and main condenser and are instead switched to a secondary condenser system which is designed to cool the reactor without the need for pumps powered by external power or generators. The isolation condenser (IC) system involved
6552-657: The expertise and knowledge to China. Subsequently, Areva managed to win a deal in February 2007, worth about €8 billion ($ 10.5 billion) for two EPRs located in Taishan , Guangdong Province in southern China, in spite of sticking to its previous conditions. The General Contractor and Operator is the China General Nuclear Power Group (CGN). The construction of the first reactor at Taishan started officially on 18 November 2009, and
6669-443: The explosion. The debris produced by the explosion damaged the mobile emergency power generator and the seawater injection lines. The seawater injection lines were repaired and put back into operation at 19:04 until the valve pit was nearly depleted of seawater at 01:10 on the 14th. The seawater injection was temporarily stopped in order to refill the valve pit with seawater using a variety of emergency service and JSDF vehicles. However,
6786-409: The final 20 km evacuation zone. 20% of residents who were within the initial 2 km radius had to evacuate more than six times. Additionally, a 30 km shelter in place order was communicated on the 15th, although some municipalities within this zone had already decided to evacuate their residents. This order was followed by a voluntary evacuation recommendation on the 25th, although
6903-443: The first half-year of 2009. The dome of the containment structure was topped out in September 2009. 90% of procurement, 80% of engineering works and 73% of civil works were completed. In June 2010, Areva announced €400 million of further provisions, taking the cost overrun to €2.7 billion. The timescale slipped from June 2012 to the end of 2012. In December 2011, TVO announced a further delay to August 2014. As of July 2012,
7020-400: The following numbers of fuel assemblies: The original design basis was a zero-point ground acceleration of 250 Gal and a static acceleration of 470 Gal, based on the 1952 Kern County earthquake (0.18 g , 1.4 m/s , 4.6 ft/s ). After the 1978 Miyagi earthquake , when the ground acceleration reached 0.125 g (1.22 m/s , 4.0 ft/s ) for 30 seconds, no damage to
7137-475: The following units were designed with new open-cycle reactor core isolation cooling (RCIC) systems. This new system used the steam from the reactor vessel to drive a turbine which would power a pump to inject water into the pressure vessel from an external storage tank to maintain the water level in the reactor vessel and was designed to operate for at least 4 hours (until the depletion of coolant or mechanical failure). Additionally, this system could be converted into
SECTION 60
#17327866100337254-573: The form of advanced boiling water reactors . On 5 August 2016, a Generation III+ VVER-1200 /392M reactor became operational (first grid connection) at Novovoronezh Nuclear Power Plant II in Russia, which was the first operational Generation III+ reactor. Several other Generation III+ reactors are under late-stage construction in Europe, China, India, and the United States. The next Generation III+ reactors to come online were an AREVA EPR reactor at
7371-455: The freshwater tank was nearly depleted. In response, injection stopped at 14:53 and the injection of seawater, which had collected in a nearby valve pit (the only other source of water), began. Power was restored to units 1 (and 2) using a mobile generator at 15:30 on 12 March. At 15:36, a hydrogen explosion damaged the secondary confinement structure (the RB). The workers evacuated shortly after
7488-542: The fuel pond had risen slightly, to 61 °C (142 °F), and water was sprayed over the pool. Power was restored to cooling systems on 24 March and by 28 March, temperatures were reported down to 35 °C (95 °F). Quantities of the released material are expressed in terms of the three predominant products released: caesium-137 , iodine-131 , and xenon-133 . Estimates for atmospheric releases range from 7–20 PBq for Cs-137, 100–400 PBq for I-131, and 6,000–12,000 PBq for Xe-133. Once released into
7605-496: The fuel. Estimates for this release vary from 1 to 5.5 PBq caesium-137 and 10-20 PBq iodine-131 . According to the French Institute for Radiological Protection and Nuclear Safety , the release from the accident represents the most important individual oceanic emissions of artificial radioactivity ever observed. The Fukushima coast has one of the world's strongest currents ( Kuroshio Current ). It transported
7722-521: The greater efficiency and therefore lower material needs of Gen III reactors, corroborates this finding. Gen III+ reactor designs are an evolutionary development of Gen III reactors, offering improvements in safety over Gen III reactor designs. Manufacturers began development of Gen III+ systems in the 1990s by building on the operating experience of the American, Japanese, and Western European light-water reactor . The nuclear industry began to promote
7839-412: The ground floor of the spent fuel building, but the switches and various other components were located below, in the basement. The third air-cooled EDG was in a separate building placed inland and at higher elevations. Although these EDGs are intended to be used with their respective reactors, switchable interconnections between unit pairs (1 and 2, 3 and 4, and 5 and 6) allowed reactors to share EDGs should
7956-440: The ground or basement levels at approximately 15:41. The switching stations that provided power from the three EDGs located higher on the hillside also failed when the building that housed them flooded. One air-cooled EDG, that of unit 6, was unaffected by the flooding and continued to operate. The DC batteries for units 1, 2, and 4 were also inoperable shortly after flooding. As a result, units 1–5 lost AC power and DC power
8073-615: The implementation of evacuations (similar to the Chernobyl nuclear accident), as they were accused of causing more harm than they prevented. Following the accident, at least 164,000 residents of the surrounding area were permanently or temporarily displaced (either voluntarily or by evacuation order). The displacements resulted in at least 51 deaths as well as stress and fear of radiological hazards. Investigations faulted lapses in safety and oversight, namely failures in risk assessment and evacuation planning. Controversy surrounds
8190-415: The isolation valves. In an emergency where backup on-site power was partially damaged or insufficient to last until a grid connection to off-site power could be restored, these cooling systems could no longer be relied upon to reliably cool the reactor. In such a case, the expected procedure was to vent both the reactor vessel and primary containment using electrically or pneumatically operated valves using
8307-437: The majority of residents had evacuated from the 30 km zone by then. The shelter in place order was lifted on April 22, but the evacuation recommendation remained. Of an estimated 2,220 patients and elderly who resided within hospitals and nursing homes within the 20 km evacuation zone, 51 fatalities are attributed to the evacuation. There was one suspected death due to radiation, as one person died 4 years later of
8424-455: The need arise. The power station was also equipped with backup DC batteries kept charged by AC power at all times, designed to be able to power the station for approximately 8 hours without EDGs. In units 1, 2, and 4, the batteries were located in the basements alongside the EDGs. In units 3, 5, and 6, the batteries were located in the turbine building where they were raised above ground level. The units and central storage facility contained
8541-406: The ocean began two hours later, and cooling of unit 3 resumed in the afternoon (approximately 16:00) and continued until cooling was lost once more as a result of site evacuation on the 15th. Unit 4 was not fueled at the time, but the unit 4 spent fuel pool (SFP) contained a number of fuel rods. On 15 March, an explosion was observed at unit 4 RB during site evacuation. A team later returned to
8658-472: The overrun range up to €1.5 billion. A further delay was announced in October 2008, making the total delay three years, giving an expected online date of 2012. The parties entered into arbitration to resolve a dispute over responsibility for the delays and final cost overruns. Areva settled the long-running dispute in 2018 by agreeing to pay €450 million for cost overruns and delays. As of May 2009,
8775-471: The plant safely in the event of an emergency. Many of the Generation III+ nuclear reactors have a core catcher . If the fuel cladding and reactor vessel systems and associated piping become molten, corium will fall into a core catcher which holds the molten material and has the ability to cool it. This, in turn protects the final barrier, the containment building . As an example, Rosatom installed
8892-587: The power plant's backup energy sources . The subsequent inability to sufficiently cool reactors after shutdown compromised containment and resulted in the release of radioactive contaminants into the surrounding environment. The accident was rated seven (the maximum severity) on the International Nuclear Event Scale by Nuclear and Industrial Safety Agency, following a report by the JNES (Japan Nuclear Energy Safety Organization). It
9009-463: The power station to inspect unit 4, but were unable to do so due to the present radiological hazard. The explosion damaged the fourth-floor rooftop area of Unit 4, creating two large holes in a wall of the RB. The explosion was likely caused by hydrogen passing to unit 4 from unit 3 through shared pipes. The following day, on the 16th, an aerial inspection was performed by helicopter which confirmed there
9126-579: The primary circuit of unit 1. This was later attributed to faulty fuel cladding. The reactor was taken offline in July 2021 and restarted in August 2022. First concrete was poured for the demonstration EPR reactor at the Flamanville Nuclear Power Plant on 6 December 2007. As the name implies, this will be the third nuclear reactor on the Flamanville site, and the second instance of an EPR being built. Electrical output will be 1630 MWe (net). The project
9243-410: The primary containment vessel and even partially eaten into its concrete foundation, coming within about 30 cm (1 ft) of leaking into the ground". A Kyoto University nuclear engineer said with regard to these estimates: "We just can't be sure until we actually see the inside of the reactors." Unit 2 was the only other operating reactor which experienced a total loss of AC and DC power. Before
9360-496: The primary containment vessel. Therefore, the steam would manually be released by venting valves to prevent a high pressure explosion. The 9.0 M W earthquake occurred at 14:46 on Friday, 11 March 2011, with the epicenter off of the east coast of the Tōhoku region . It produced maximum ground g-force of 560 Gal , 520 Gal, 560 Gal at units 2, 3, and 5 respectively. This exceeded the seismic reactor design tolerances of 450 Gal, 450 Gal, and 460 Gal for continued operation, but
9477-496: The process of restarting seawater injection was interrupted by another explosion in unit 3 RB at 11:01 which damaged water lines and prompted another evacuation. Injection of seawater into unit 1 would not resume until that evening, after 18 hours without cooling. Subsequent analysis in November 2011 suggested that this extended period without cooling resulted in the melting of the fuel in unit 1, most of which would have escaped
9594-526: The project has since seen several severe cost increases and delays, with latest published cost estimates (from 2012) of more than €8 billion. The station was initially scheduled to go online in 2009. In May 2006, construction delays of about one year were announced, following quality control problems across the construction. In part, the delays were due to the lack of oversight of subcontractors inexperienced in nuclear construction. The delays led to disappointing financial results for Areva. It blamed delays on
9711-468: The reactor by operating the safety relief valves using batteries collected from nearby automobiles. This was shortly followed by the bursting of the venting line rupture disk and the depressurization of the PCV. Unfortunately, venting was quickly stopped by a pneumatic isolation valve which closed on the vent path due to a lack of compressed air, and venting was not resumed until over 6 hours later once an external air compressor could be installed. Despite this,
9828-414: The reactor operators began planning to lower the PCV pressure by venting. The PCV reached its maximum pressure of 0.84 MPa at 02:30 on 12 March, after which it stabilized around 0.8 MPa. The decrease in pressure was due to an uncontrolled vent via an unknown pathway. The plant was notified Okuma town completed evacuation at 9:02 on 12 March. The staff subsequently began controlled venting. Venting of
9945-399: The reactor pressure was immediately low enough to allow for water injection (borated freshwater, as ordered by TEPCO) using the FP system until the freshwater FP tanks were depleted, at which point the injected coolant was switched to seawater from the valve pit. Cooling was lost once the valve pit was depleted but was resumed two hours later (unit 1 cooling was postponed until the valve pit
10062-426: The reactor vessel. However, the reactor pressure had already increased to many times greater than the limit of the DDFP. Additionally, the team detected high levels of radiation within the secondary confinement structure, indicating damage to the reactor core, and found that the primary containment vessel (PCV) pressure (0.6 MPa ) exceeded design specifications (0.528 MPa). In response to this new information,
10179-417: The regulator, ASN, reported further welding problems on the secondary containment steel liner. The same month, EDF announced that costs had increased 50% to €5 billion, and commissioning was delayed by about two years to 2014. In July 2011, EDF announced that the estimated costs had escalated to €6 billion, and that completion of construction was delayed to 2016. In December 2012, EDF announced that
10296-506: The remaining electricity on site. This would lower the reactor pressure sufficiently to allow for low-pressure injection of water into the reactor using the fire protection system to replenish water lost to evaporation. Station operators switched the reactor control to off-site power for shutdown, but the system was damaged by the earthquake. Emergency diesel generators (EDG) then automatically started to provide AC power. Two EDGs were available for each of units 1–5 and three for unit 6. Of
10413-617: The second half of 2017 and the first half of 2018. In December 2017, Hong Kong media reported that a component had cracked during testing, needing to be replaced. In January 2018, commissioning was rescheduled again, with commercial operation expected in 2018 and 2019. In June 2018, Taishan 1 achieved criticality for the first time. On 29 June 2018, Taishan 1 was connected to the grid. It entered commercial operation in December 2018. Taishan 2 reached these milestones in May 2019 June 2019 and September 2019, respectively. The Taishan project
10530-624: The second on 15 April 2010. Construction of each unit was then planned to take 46 months, significantly faster and cheaper than the first two EPRs in Finland and France. The reactor pressure vessel of the first reactor was installed in June 2012, and the second in November 2014. The first pressure vessel had been imported from Mitsubishi Heavy Industries in Japan, and steam generators from Areva in France. The second pressure vessel and associated steam generators had been made in China, by Dongfang Electric and Shanghai Electric . In 2014, construction
10647-455: The seismic values were within the design tolerances of unit 6. Upon detecting the earthquake, all three operating reactors (units 1, 2, and 3) automatically shut down. Due to expected grid failure and damage to the switch station as a result of the earthquake, the power station automatically started up the EDGs, isolated the reactor from the primary coolant loops, and activated the emergency shutdown cooling systems. The largest tsunami wave
10764-429: The station was at least three and a half years behind schedule and more than 50 percent over-budget. Areva and the utility involved "are in bitter dispute over who will bear the cost overruns and there is a real risk now that the utility will default". In August 2009, Areva announced €550 million additional provisions for the build, taking station costs to €5.3 billion, and wiped out interim operating profits for
10881-633: The station was scheduled to start electricity production no earlier than 2015, a schedule slippage of at least six years. In December 2012 Areva's Chief Executive estimated costs to €8 billion. In September 2014, Areva announced that operations would start in 2018. In October 2017, the date was pushed back to the spring of 2019. During testing between 2018 and 2021, multiple further delays were announced, of around three years in total. Olkiluoto 3 achieved first criticality in December 2021. Grid connection took place in March 2022. In May 2022, foreign material
10998-459: The steel containment vessel and the concrete shield building around the AP1000 in that its containment vessel does not have sufficient safety margins in the event of a direct airplane strike. Other engineers do not agree with these concerns, and claim the containment building is more than sufficient in safety margins and factors of safety . The Union of Concerned Scientists in 2008 referred to
11115-625: The televised news media. Citizens were informed by radio, trucks with megaphones, and door to door visits. Many municipalities independently ordered evacuations ahead of orders from the national government due to loss of communication with authorities; at the time of the 3 km evacuation order, the majority of residents within the zone had already evacuated. Due to the multiple overlapping evacuation orders, many residents had evacuated to areas which would shortly be designated as evacuation areas. This resulted in many residents having to move multiple times until they reached an area outside of
11232-412: The tsunami, operators attempted to manually open the IC control valve, but the IC failed to function, suggesting that the isolation valves were closed. Although they were kept open during IC operation, the loss of DC power in unit 1 (which occurred shortly before the loss of AC power) automatically closed the AC-powered isolation valves to prevent uncontrolled cooling or a potential LOC. Although this status
11349-462: The tsunami. The isolation condenser (IC) was functioning prior to the tsunami, but the DC-operated control valve outside of the primary containment had been in the closed position at the time to prevent thermal stresses on the reactor components. Some indications in the control room stopped functioning and operators correctly assumed loss of coolant (LOC). At 18:18 on 11 March, a few hours after
11466-500: The unit itself began. This was expected to last 54 months, with commissioning planned for 2012. In April 2008, the French nuclear safety authority ( Autorité de sûreté nucléaire , ASN) reported that a quarter of the welds inspected in the secondary containment steel liner are not in accordance with norms, and that cracks have been found in the concrete base. EDF stated that progress was being made on these issues, which were raised very early in construction; however, on 21 May, ASN ordered
11583-450: The whole satisfactory, though identifying areas for further examination. The most notable simplification is a single layer containment building with a liner as opposed to the EPR's double layer with a liner. ASN highlighted that the EPR design basis assumption that primary and secondary cooling circuit piping would not fail may no longer be appropriate for the simplified EPR2, and requires additional safety demonstrations. Another simplification
11700-489: Was 13–14 m (43–46 feet) high and hit approximately 50 minutes after the initial earthquake, overtopping the seawall and exceeding the plant's ground level, which was 10 m (33 ft) above sea level. The waves first damaged the seawater pumps along the shoreline, 10 of the plant's 13 cooling systems for the emergency diesel generators (EDG). The waves then flooded all turbine and reactor buildings, damaging EDGs and other electrical components and connections located on
11817-406: Was China's Taishan 1 , which started commercial operation in December 2018. Taishan 2 started commercial operation in September 2019. European units have been so far plagued with prolonged construction delays and substantial cost overruns. The first EPR unit to start construction, at Olkiluoto in Finland, originally intended to be commissioned in 2009, started commercial operation in 2023,
11934-414: Was accelerated by the impact of the 2021 global energy crisis . In June 2023, EDF announced it was starting the authorisation process to build two EPR2 reactors at Penly Nuclear Power Plant . The EPR2 requires 250 types of pipes instead of 400 for the EPR, 571 valves instead of 13,300 valves for the EPR, and 100 types of doors instead of 300 in the EPR. The EPR2 also uses more prefabricated components, and
12051-598: Was being worked on, which would be easier to build, and be ready for orders from about 2020, describing it in 2016 as "a reactor offering the same characteristics as today’s EPR but it will be cheaper to build with optimised construction times and costs". In 2016, EDF planned to build two new model EPR reactors in France by 2030 to prepare for renewing its fleet of older reactors. However, following financial difficulties at Areva and its merger with EDF, French Ecology Minister Nicolas Hulot said in January 2018, "for now [building
12168-408: Was considering designing two new lower powered reactors, one with output of 1500 MWe and the other 1000 MWe. Machenaud stated there would be a period of reflection on the best way to improve the EPR design to lower its price and incorporate post-Fukushima safety improvements. In September 2015, EDF's chief executive Jean-Bernard Lévy stated that the design of a "New Model" EPR, or "EPR2",
12285-457: Was damaged and the isolation valve for the PCV vent was found to be closed and inoperable. At 13:00 on the 14th, the RCIC pump for unit 2 failed after 68 hours of continuous operation. With no way to vent the PCV, in response, a plan was devised to delay containment failure by venting the reactor vessel into the PCV using the SRVs to allow for seawater injection into the reactor vessel. The following morning (March 15, 06:15), another explosion
12402-416: Was established nearly simultaneously at 21:23. The evacuation radius was expanded to 10 km at 5:44, and was then revised to 20 km at 18:25. The size of these evacuation zones was set for arbitrary reasons at the discretion of bureaucrats rather than nuclear experts. Communication between different authorities was scattered and at several times the local governments learned the status of evacuation via
12519-639: Was filled). However, despite being cooled, PCV pressure continued to rise and the RPV water level continued to drop until the fuel became uncovered on the morning of the 14th (6:20), as indicated by a water level gauge, which was followed by workers evacuating the area out of concerns about a possible second hydrogen explosion similar to unit 1. Shortly after work resumed to reestablish coolant lines, an explosion occurred in unit 3 RB at 11:01 on March 14, which further delayed unit 1 cooling and damaged unit 3's coolant lines. Work to reestablish seawater cooling directly from
12636-400: Was found in the turbine steam reheater, and the plant was shut down for about three months of repair work. Regular production had been expected to begin in December 2022, after a test production phase. On 28 October 2022, it was announced cracks of a few centimetres had been found in all four of the feedwater pump impellers. The cause of the cracks was yet to be determined, and it was unclear how
12753-533: Was heard on site coinciding with a rapid drop of suppression chamber pressure to atmospheric pressure, interpreted as a malfunction of suppression chamber pressure measurement. Due to concerns about the growing radiological hazard on site, almost all workers evacuated to the Fukushima Daini Nuclear Power Plant . Although AC power was lost, some DC power was still available in unit 3 and the workers were able to remotely confirm that
12870-412: Was lost in units 1, 2, and 4. In response, the operators assumed a loss of coolant in units 1 and 2 and developed a plan in which they would vent the primary containment and inject water into the reactor vessels with firefighting equipment. Tokyo Electric Power Company ( TEPCO ), the utility operator and owner, notified authorities of a "first-level emergency". Two workers were killed by the impact of
12987-424: Was manually reconfigured at 05:00 to recirculate water from the suppression chamber instead. On the 13th, unit 2 was configured to vent the PCV automatically (manually opening all valves, leaving only the rupture disk) and preparations were made to inject seawater from the valve pit via the FP system should the need arise. However, as a result of the explosion in unit 3 the following day, the seawater injection setup
13104-404: Was not possible, as the reactor was not producing sufficient steam. However, the water within the RPV proved sufficient to cool the fuel, with the SRVs venting into the PCV, until AC power was restored on March 13 using the unit 6 interconnection, allowing the use of the low-pressure pumps of the residual heat removal (RHR) system. Unit 5 was the first to achieve a cold shutdown in the afternoon on
13221-464: Was paid for one death from lung cancer , but this does not prove a causal relationship between radiation and the cancer. Six other persons have been reported as having developed cancer or leukemia . Two workers were hospitalized because of radiation burns , and several other people sustained physical injuries as a consequence of the accident. Criticisms have been made about the public perception of radiological hazards resulting from accidents and
13338-485: Was planned to involve around €3.3 billion of capital expenditure from EDF . From 19 October 2005 to 18 February 2006, the project was submitted to a national public debate. On 4 May 2006, the decision was made by EDF's Board of Directors to continue with the construction. Between 15 June and 31 July 2006, the unit underwent a public enquiry, which rendered a "favourable opinion" on the project. That summer, site preparation works began. In December 2007, construction of
13455-404: Was reported to be running over two years late, mainly due to key component delays and project management issues. Cold function tests were performed on Taishan 1 in February 2016, with start up expected in the first half of 2017. Taishan 2 was scheduled to start up later that year. However, commissioning dates were put back six months in February 2017, with commercial operation expected in
13572-448: Was sufficient water remaining in the SFP. On the 20th, water was sprayed into the uncovered SFP, later replaced by a concrete pump truck with a boom on the 22nd. Unit 5 was fueled and was undergoing an RPV pressure test at the time of the accident, but the pressure was maintained by an external air compressor and the reactor was not otherwise operating. Removal of decay heat using the RCIC
13689-435: Was unknown to the plant operators, they correctly interpreted the loss of function in the IC system and manually closed the control valves. The plant operators would continue to periodically attempt to restart the IC in the following hours and days, but it did not function. The plant operators then attempted to use the building's fire protection (FP) equipment, operated by a diesel-driven fire pump (DDFP), to inject water into
#32967