Nuclear Power / Nuclear Energy / Nuclear Risk: How does a pressurized water reactor work?
Many nuclear power plants operate with pressurized water reactors (PWRs). The PWR is the most common reactor type. Nuclear fission of the fuel elements heats up the water in the reactor to approximately 315°C (600°F). The water is constantly kept under pressure (about 2200 psig [15 Mpa]). To control or shut down a nuclear reactor, control rods are used. When a control rod is inserted in the reactor core, it absorbs a part of the neutrons released by the nuclear fission events. Thus, the neutrons are not available to trigger off further nuclear fissions. In this way uncontrolled increase of chain-reactions in the reactor is prevented. The 315°C warm water by means of a heat exchanger (here called steam generator) heats up the secondary coolant loop. In the secondary coolant loop the steam generator forms steam which drives the turbine.
Every nuclear power plant (PWRs as well) in one year´s operating time produces the radioactivity of a hiroshima bomb per megawatt of electric power. This means that in a nuclear power plant with an annual power of 1200 MW the radioactivity of approximately 1200 hiroshima bombs comes into existence. Certain parts of the radioactive material decay very quickly. Others, however, have half-lives longer than 24,000 years (e.g. plutonium) and therefore will factually exist permanently. Ageing nuclear power plants with extended operating times and embrittled reactor vessels heighten the risk of an accident.
This type of reactor is not technically safe, as could be seen from the nuclear meltdown in the almost new PWR in 1979 in Harrisburg, U.S. (Three Mile Island accident). In case of an accident or a terrorist attack the nuclear power plant is shut down by means of the control rods. However, for a period of several days after the shutdown the radioactive decay of the fission products continues to generate heat.
All nuclear power plants are provided with redundant emergency cooling systems to safely remove the decay heat also in the event of a disaster. When the cooling systems break down (as it occurred during the Three Mile Island accident), the rising temperature can cause a nuclear meltdown. If the fuel assemblies in the core melt, the rate of chain reactions will increase and lead to an extreme and uncontrolled heating-up process. When the reactor vessel does not resist or when a huge amount of radiation emerges, the accident is called 'maximum credible accident' [Super-GAU].
PWR – Not safe from terrorist attacks and plane crashes
The Oekoinstitut [ecological institute] Darmstadt has calculated the areal impact of a disaster of the kind described above, using the PWR of the French nuclear power plant Fessenheim as an example. The study was based on an assumed major accident in the French EDF/EnBW- nuclear power plant Fessenheim:
In case of south-west wind and rain, the area of damage would have a spread of up to 370 km from Fessenheim to the region of Würzburg-Nürnberg. If the Chernobyl guidelines were adopted, in this zone all inhabitants would have to be evacuated for a period of 50 years.
Klaus Traube (nuclear expert; former director of AEG´s nuclear reactor department at General Dynamics, San Diego; after this, head of Interatom) wrote:
The analysis of numerous hazardous incidents shows that they usually are triggered off by an unexpected concurrence of malfunctions and operating errors (like for example in the Harrisburg/Three Mile Island accident and, by the way, in Chernobyl as well). Individually, the malfunctions and errors seem to be trivial. Elaborate risk studies dealing with the possibilities and probabilities of a nuclear reactor´s disastrous breakdown arrive at the same conclusion. They confirm: Every running reactor at any time renders possible accidents leading to nuclear meltdowns with a subsequent disastrous release of radioactivity. Not the truth of this statement, but solely the probability of occurrence is debated among experts. Furthermore, it is a fact that acts of terrorism (like for example plane crashes) can cause a nuclear disaster. Again, solely the probability is debatable.
Axel Mayer
Climate Change, Nuclear Energy and Fukushima...
Saving the Climate with Nuclear Energy? The nuclear power industry and its governmental allies are spending tens of millions of dollars annually to promote atomic power as an “emissions-free” energy source. Their goal is to encourage the construction of new nuclear reactors in the U.S. in France, England and worldwide and prevent the shutdown of dangerous old reactors (Fessenheim, Beznau, Mühleberg....) that cannot compete economically with clean energy sources like wind and solar power..
Yet nuclear power is not only ineffective at addressing climate change, when the entire fuel chain is examined, nuclear power is a net producer of greenhouse gases. Adding enough nuclear power to make a meaningful reduction in greenhouse gas emissions would cost trillions of dollars, create tens of thousands of tons of lethal high-level radioactive waste, contribute to further proliferation of nuclear weapons materials, result in a Chernobyl or Fukushima-scale accident once every decade or so, and, perhaps most significantly, squander the resources necessary to implement meaningful climate change policies. Source of this section and where to go for up-to-date information on nuclear power and climate.
Danger: Nuclear Reactors worldwide / Nuclear Power / Nuclear Energy / Nuclear Risk (18.10.07)
(World Nuclear Association) Almaraz-1, Spain, PWR Almaraz-2, Spain, PWR Angra-1, Brazil, PWR Angra-2, Brazil, PWR Arkansas Nuclear One-1, United States, PWR Arkansas Nuclear One-2, United States, PWR Armenia-2 (Metsamor), Armenia, PWR/VVER Asco-1, Spain, PWR Asco-2, Spain, PWR Atucha-1, Argentina, PHWR Balakovo-1, Russian Federation, PWR/VVER Balakovo-2, Russian Federation, PWR/VVER Balakovo-3, Russian Federation, PWR/VVER Balakovo-4, Russian Federation, PWR/VVER Beaver Valley-1, United States, PWR Beaver Valley-2, United States, PWR Belleville-1, France, PWR Belleville-2, France, PWR Beloyarsk-3 (BN-600), Russian Federation, FBR Beznau-1, Switzerland, PWR Beznau-2, Switzerland, PWR Biblis-A, Germany, PWR Biblis-B, Germany, PWR Bilibino unit A, Russian Federation, LWGR/EGP Bilibino unit B, Russian Federation, LWGR/EGP Bilibino unit C, Russian Federation, LWGR/EGP Bilibino unit D, Russian Federation, LWGR/EGP Blayais-1, France, PWR Blayais-2, France, PWR Blayais-3, France, PWR Blayais-4, France, PWR Bohunice-1, Slovak Republic, PWR/VVER Bohunice-2, Slovak Republic, PWR/VVER Bohunice-3, Slovak Republic, PWR/VVER Bohunice-4, Slovak Republic, PWR/VVER Borssele, Netherlands, PWR Braidwood-1, United States, PWR Braidwood-2, United States, PWR Brokdorf, Germany, PWR Browns Ferry-2, United States, BWR Browns Ferry-3, United States, BWR Bruce-3, Canada, PHWR/CANDU Bruce-4, Canada, PHWR/CANDU Bruce-5, Canada, PHWR/CANDU Bruce-6, Canada, PHWR/CANDU Bruce-7, Canada, PHWR/CANDU Bruce-8, Canada, PHWR/CANDU Brunsbuttel, Germany, BWR Brunswick-1, United States, BWR Brunswick-2, United States, BWR Bugey-2, France, PWR Bugey-3, France, PWR Bugey-4, France, PWR Bugey-5, France, PWR Byron-1, United States, PWR Byron-2, United States, PWR Callaway-1, United States, PWR Calvert Cliffs-1, United States, PWR Calvert Cliffs-2, United States, PWR Catawba-1, United States, PWR Catawba-2, United States, PWR Cattenom-1, France, PWR Cattenom-2, France, PWR Cattenom-3, France, PWR Cattenom-4, France, PWR Cernavoda-1, Romania, PHWR/CANDU Chasnupp-1, Pakistan, PWR Chin Shan-1, Taiwan, BWR Chin Shan-2, Taiwan, BWR Chinon-B1, France, PWR Chinon-B2, France, PWR Chinon-B3, France, PWR Chinon-B4, France, PWR Chooz-B1, France, PWR Chooz-B2, France, PWR Civaux-1, France, PWR Civaux-2, France, PWR Clinton-1, United States, BWR Cofrentes, Spain, BWR Columbia (WNP-2), United States, BWR Comanche Peak-1, United States, PWR Comanche Peak-2, United States, PWR Cooper, United States, BWR Cruas-1, France, PWR Cruas-2, France, PWR Cruas-3, France, PWR Cruas-4, France, PWR Crystal River-3, United States, PWR Dampierre-1, France, PWR Dampierre-2, France, PWR Dampierre-3, France, PWR Dampierre-4, France, PWR Darlington-1, Canada, PHWR/CANDU Darlington-2, Canada, PHWR/CANDU Darlington-3, Canada, PHWR/CANDU Darlington-4, Canada, PHWR/CANDU Davis Besse-1, United States, PWR Diablo Canyon-1, United States, PWR Diablo Canyon-2, United States, PWR Doel-1, Belgium, PWR Doel-2, Belgium, PWR Doel-3, Belgium, PWR Doel-4, Belgium, PWR Donald Cook-1, United States, PWR Donald Cook-2, United States, PWR Dresden-2, United States, BWR Dresden-3, United States, BWR Duane Arnold-1, United States, BWR Dukovany-1, Czech Republic, PWR/VVER Dukovany-2, Czech Republic, PWR/VVER Dukovany-3, Czech Republic, PWR/VVER Dukovany-4, Czech Republic, PWR/VVER Dungeness-A1, United Kingdom, GCR (Magnox) Dungeness-A2, United Kingdom, GCR (Magnox) Dungeness-B1, United Kingdom, AGR Dungeness-B2, United Kingdom, AGR Embalse, Argentina, PHWR Emsland, Germany, PWR Enrico Fermi-2, United States, BWR Farley-1, United States, PWR Farley-2, United States, PWR Fessenheim-1, France, PWR Fessenheim-2, France, PWR Fitzpatrick, United States, BWR Flamanville-1, France, PWR Flamanville-2, France, PWR Forsmark-1, Sweden, BWR Forsmark-2, Sweden, BWR Forsmark-3, Sweden, BWR Fort Calhoun-1, United States, PWR Fukushima-Daiichi-1, Japan, BWR Fukushima-Daiichi-2, Japan, BWR Fukushima-Daiichi-3, Japan, BWR Fukushima-Daiichi-4, Japan, BWR Fukushima-Daiichi-5, Japan, BWR Fukushima-Daiichi-6, Japan, BWR Fukushima-Daini-1, Japan, BWR Fukushima-Daini-2, Japan, BWR Fukushima-Daini-3, Japan, BWR Fukushima-Daini-4, Japan, BWR Genkai-1, Japan, PWR Genkai-2, Japan, PWR Genkai-3, Japan, PWR Genkai-4, Japan, PWR Gentilly-2, Canada, PHWR/CANDU Goesgen, Switzerland, PWR Golfech-1, France, PWR Golfech-2, France, PWR Grafenrheinfeld, Germany, PWR Grand Gulf-1, United States, BWR Gravelines-1, France, PWR Gravelines-2, France, PWR Gravelines-3, France, PWR Gravelines-4, France, PWR Gravelines-5, France, PWR Gravelines-6, France, PWR Grohnde, Germany, PWR Guangdong-1 (Daya Bay 1), China, mainland, PWR Guangdong-2 (Daya Bay 2), China, mainland, PWR Gundremmingen-B, Germany, BWR Gundremmingen-C, Germany, BWR H B Robinson-2, United States, PWR Hamaoka-1, Japan, BWR Hamaoka-2, Japan, BWR Hamaoka-3, Japan, BWR Hamaoka-4, Japan, BWR Hamaoka-5, Japan, ABWR Hartlepool-1, United Kingdom, AGR Hartlepool-2, United Kingdom, AGR Hatch-1, United States, BWR Hatch-2, United States, BWR Heysham-A1, United Kingdom, AGR Heysham-A2, United Kingdom, AGR Heysham-B1, United Kingdom, AGR Heysham-B2, United Kingdom, AGR Hinkley Point-B1, United Kingdom, AGR Hinkley Point-B2, United Kingdom, AGR Hope Creek-1, United States, BWR Hunterston-B1, United Kingdom, AGR Hunterston-B2, United Kingdom, AGR Ignalina-2, Lithuania, LWGR/RBMK Ikata-1, Japan, PWR Ikata-2, Japan, PWR Ikata-3, Japan, PWR Indian Point-2, United States, PWR Indian Point-3, United States, PWR Isar-1, Germany, BWR Isar-2, Germany, PWR Jose Cabrera-1 (Zorita), Spain, PWR Kaiga-1, India, PHWR Kaiga-2, India, PHWR Kakrapar-1, India, PHWR Kakrapar-2, India, PHWR Kalinin-1, Russian Federation, PWR/VVER Kalinin-2, Russian Federation, PWR/VVER Kalinin-3, Russian Federation, PWR/VVER Kanupp, Pakistan, PHWR Kashiwazaki Kariwa-1, Japan, BWR Kashiwazaki Kariwa-2, Japan, BWR Kashiwazaki Kariwa-3, Japan, BWR Kashiwazaki Kariwa-4, Japan, BWR Kashiwazaki Kariwa-5, Japan, BWR Kashiwazaki Kariwa-6, Japan, ABWR Kashiwazaki Kariwa-7, Japan, ABWR Khmelnitski-1, Ukraine, PWR/VVER Khmelnitski-2, Ukraine, PWR/VVER Koeberg-1, South Africa, PWR Koeberg-2, South Africa, PWR Kola-1, Russian Federation, PWR/VVER Kola-2, Russian Federation, PWR/VVER Kola-3, Russian Federation, PWR/VVER Kola-4, Russian Federation, PWR/VVER Kori-1, Korea RO (South), PWR Kori-2, Korea RO (South), PWR Kori-3, Korea RO (South), PWR Kori-4, Korea RO (South), PWR Kozloduy-3, Bulgaria, PWR/VVER Kozloduy-4, Bulgaria, PWR/VVER Kozloduy-5, Bulgaria, PWR/VVER Kozloduy-6, Bulgaria, PWR/VVER Krsko, Slovenia, PWR Krummel, Germany, BWR Kuosheng-1, Taiwan, BWR Kuosheng-2, Taiwan, BWR Kursk-1, Russian Federation, LWGR/RBMK Kursk-2, Russian Federation, LWGR/RBMK Kursk-3, Russian Federation, LWGR/RBMK Kursk-4, Russian Federation, LWGR/RBMK Laguna Verde-1, Mexico, BWR Laguna Verde-2, Mexico, BWR LaSalle-1, United States, BWR LaSalle-2, United States, BWR Leibstadt, Switzerland, BWR Leningrad-1, Russian Federation, LWGR/RBMK Leningrad-2, Russian Federation, LWGR/RBMK Leningrad-3, Russian Federation, LWGR/RBMK Leningrad-4, Russian Federation, LWGR/RBMK Limerick-1, United States, BWR Limerick-2, United States, BWR Lingao-1, China, mainland, PWR Lingao-2, China, mainland, PWR Loviisa-1, Finland, PWR/VVER Loviisa-2, Finland, PWR/VVER Maanshan-1, Taiwan, PWR Maanshan-2, Taiwan, PWR Madras-1, India, PHWR Madras-2, India, PHWR McGuire-1, United States, PWR McGuire-2, United States, PWR Mihama-1, Japan, PWR Mihama-2, Japan, PWR Mihama-3, Japan, PWR Millstone-2, United States, PWR Millstone-3, United States, PWR Mochovce-1, Slovak Republic, PWR/VVER Mochovce-2, Slovak Republic, PWR/VVER Monticello, United States, BWR Muehleberg, Switzerland, BWR Narora-1, India, PHWR Narora-2, India, PHWR Neckarwestheim-1, Germany, PWR Neckarwestheim-2, Germany, PWR Nine Mile Point-1, United States, BWR Nine Mile Point-2, United States, BWR Nogent-1, France, PWR Nogent-2, France, PWR North Anna-1, United States, PWR North Anna-2, United States, PWR Novovoronezh-3, Russian Federation, PWR/VVER Novovoronezh-4, Russian Federation, PWR/VVER Novovoronezh-5, Russian Federation, PWR/VVER Oconee-1, United States, PWR Oconee-2, United States, PWR Oconee-3, United States, PWR Ohi-1, Japan, PWR Ohi-2, Japan, PWR Ohi-3, Japan, PWR Ohi-4, Japan, PWR Oldbury-1, United Kingdom, GCR (Magnox) Oldbury-2, United Kingdom, GCR (Magnox) Olkiluoto-1, Finland, BWR Olkiluoto-2, Finland, BWR Onagawa-1, Japan, BWR Onagawa-2, Japan, BWR Onagawa-3, Japan, BWR Oskarshamn-1, Sweden, BWR Oskarshamn-2, Sweden, BWR Oskarshamn-3, Sweden, BWR Oyster Creek, United States, BWR Paks-1, Hungary, PWR Paks-2, Hungary, PWR Paks-3, Hungary, PWR Paks-4, Hungary, PWR Palisades, United States, PWR Palo Verde-1, United States, PWR Palo Verde-2, United States, PWR Palo Verde-3, United States, PWR Paluel-1, France, PWR Paluel-2, France, PWR Paluel-3, France, PWR Paluel-4, France, PWR Peach Bottom-2, United States, BWR Peach Bottom-3, United States, BWR Penly-1, France, PWR Penly-2, France, PWR Perry-1, United States, BWR Phenix, France, FBR Philippsburg-1, Germany, BWR Philippsburg-2, Germany, PWR Pickering-1, Canada, PHWR/CANDU Pickering-4, Canada, PHWR/CANDU Pickering-5, Canada, PHWR/CANDU Pickering-6, Canada, PHWR/CANDU Pickering-7, Canada, PHWR/CANDU Pickering-8, Canada, PHWR/CANDU Pilgrim-1, United States, BWR Point Beach-1, United States, PWR Point Beach-2, United States, PWR Point Lepreau, Canada, PHWR/CANDU Prairie Island-1, United States, PWR Prairie Island-2, United States, PWR Qinshan-1, China, mainland, PWR Qinshan-2, China, mainland, PWR Qinshan-3, China, mainland, PWR Qinshan-4, China, mainland, PHWR/CANDU Qinshan-5, China, mainland, PHWR/CANDU Quad Cities-1, United States, BWR Quad Cities-2, United States, BWR R E Ginna, United States, PWR Rajasthan-1, India, PHWR Rajasthan-2, India, PHWR Rajasthan-3, India, PHWR Rajasthan-4, India, PHWR Ringhals-1, Sweden, BWR Ringhals-2, Sweden, PWR Ringhals-3, Sweden, PWR Ringhals-4, Sweden, PWR River Bend-1, United States, BWR Rovno-1, Ukraine, PWR/VVER Rovno-2, Ukraine, PWR/VVER Rovno-3, Ukraine, PWR/VVER Rovno-4, Ukraine, PWR/VVER Salem-1, United States, PWR Salem-2, United States, PWR San Onofre-2, United States, PWR San Onofre-3, United States, PWR Santa Maria de Garona, Spain, BWR Seabrook-1, United States, PWR Sendai-1, Japan, PWR Sendai-2, Japan, PWR Sequoyah-1, United States, PWR Sequoyah-2, United States, PWR Shearon Harris-1, United States, PWR Shika-1, Japan, BWR Shimane-1, Japan, BWR Shimane-2, Japan, BWR Sizewell-A1, United Kingdom, GCR (Magnox) Sizewell-A2, United Kingdom, GCR (Magnox) Sizewell-B, United Kingdom, PWR Smolensk-1, Russian Federation, LWGR/RBMK Smolensk-2, Russian Federation, LWGR/RBMK Smolensk-3, Russian Federation, LWGR/RBMK South Texas-1, United States, PWR South Texas-2, United States, PWR South Ukraine-1, Ukraine, PWR/VVER South Ukraine-2, Ukraine, PWR/VVER South Ukraine-3, Ukraine, PWR/VVER St. Alban-1, France, PWR St. Alban-2, France, PWR St. Laurent-B1, France, PWR St. Laurent-B2, France, PWR St. Lucie-1, United States, PWR St. Lucie-2, United States, PWR Surry-1, United States, PWR Surry-2, United States, PWR Susquehanna-1, United States, BWR Susquehanna-2, United States, BWR Takahama-1, Japan, PWR Takahama-2, Japan, PWR Takahama-3, Japan, PWR Takahama-4, Japan, PWR Tarapur-1, India, BWR Tarapur-2, India, BWR Tarapur-4, India, PHWR Temelin-1, Czech Republic, PWR/VVER Temelin-2, Czech Republic, PWR/VVER Three Mile Island-1, United States, PWR Tianwan-1, China, mainland, PWR/VVER Tihange-1, Belgium, PWR Tihange-2, Belgium, PWR Tihange-3, Belgium, PWR Tokai-2, Japan, BWR Tomari-1, Japan, PWR Tomari-2, Japan, PWR Torness unit A, United Kingdom, AGR Torness unit B, United Kingdom, AGR Tricastin-1, France, PWR Tricastin-2, France, PWR Tricastin-3, France, PWR Tricastin-4, France, PWR Trillo-1, Spain, PWR Tsuruga-1, Japan, BWR Tsuruga-2, Japan, PWR Turkey Point-3, United States, PWR Turkey Point-4, United States, PWR Ulchin-1, Korea RO (South), PWR Ulchin-2, Korea RO (South), PWR Ulchin-3, Korea RO (South), PWR Ulchin-4, Korea RO (South), PWR Ulchin-5, Korea RO (South), PWR Unterweser, Germany, PWR Vandellos-2, Spain, PWR Vermont Yankee, United States, BWR Virgil C Summer-1, United States, PWR Vogtle-1, United States, PWR Vogtle-2, United States, PWR Volgodonsk-1 (Rostov), Russian Federation, PWR/VVER Waterford-3, United States, PWR Watts Bar-1, United States, PWR Wolf Creek, United States, PWR Wolsong-1, Korea RO (South), PHWR Wolsong-2, Korea RO (South), PHWR Wolsong-3, Korea RO (South), PHWR Wolsong-4, Korea RO (South), PHWR Wylfa-1, United Kingdom, GCR (Magnox) Wylfa-2, United Kingdom, GCR (Magnox) Yonggwang-1, Korea RO (South), PWR Yonggwang-2, Korea RO (South), PWR Yonggwang-3, Korea RO (South), PWR Yonggwang-4, Korea RO (South), PWR Yonggwang-5, Korea RO (South), PWR Yonggwang-6, Korea RO (South), PWR Zaporozhe-1, Ukraine, PWR/VVER Zaporozhe-2, Ukraine, PWR/VVER Zaporozhe-3, Ukraine, PWR/VVER Zaporozhe-4, Ukraine, PWR/VVER Zaporozhe-5, Ukraine, PWR/VVER Zaporozhe-6, Ukraine, PWR/VVER
Nuclear Power / Nuclear Energy / Nuclear Risk
Legende:
PWR = Pressurized Water Reactors BWR = Boiling Water Reactors CANDU = Pressurized Heavy Water Reactor AGR = Advanced Gas-cooled Reactor VVER = Vodo-Vodyanoi Energetichesky Reactor PHWR = Pressurised Heavy Water Reactor LWGR = grahite moderated light water cooled RBMK = Reaktor Bolshoy Moshchnosti Kanalniy ABWR = Advanced Boiling Water Reactor EGP = graphite channel power reactor with steam overheat FBR = Fast Breeder Reactor GCR (Magnox) = Gas Cooled Reactor
