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Topic: Boiling water reactor


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In the News (Fri 5 Sep 08)

  
 Types of Nuclear Reactors
In the boiling water reactor the same water loop serves as moderator, coolant for the core, and steam source for the turbine.
In the boiling water reactor (BWR), the water which passes over the reactor core to act as moderator and coolant is also the steam source for the turbine.
In the pressurized water reactor (PWR), the water which passes over the reactor core to act as moderator and coolant does not flow to the turbine, but is contained in a pressurized primary loop.
hyperphysics.phy-astr.gsu.edu /hbase/nucene/reactor.html#c3   (282 words)

  
 Pressurized water reactor - Wikipedia, the free encyclopedia
In having this secondary loop, the PWR differs from the boiling water reactor (BWR), in which the primary coolant is allowed to boil in the reactor core and drive a turbine directly.
Water flows in between the fuel rods from the bottom to the top of the reactor -- the bundles are 12 to 14 feet long depending on the vintage of the reactor.
A disadvantage is that the reactor is susceptible to produce power at rates that result in damage to fuel in the event of introduction of cold water into the reactor or in the event the secondary system experiences a steam line rupture.
en.wikipedia.org /wiki/Pressurized_water_reactor   (1709 words)

  
 Light water reactor
The reactor core consisting of fuel and control elements is enclosed by a water-filled steel pressure vessel.
The heat generated by the fission heats the water which evaporates in the pressure vessel in a boiling water reactor but, in the pressurized water reactor, the steam evaporates in a steam generator of a secondary circuit.
The water required to cool the condenser is taken from a river and refed into the river in warmed condition or the heat is dissipated via a cooling tower into the atmosphere.
www.euronuclear.org /info/encyclopedia/l/lightwaterreactor.htm   (170 words)

  
 Boiling water reactor
Nuclear reactor with water as a coolant and as a moderator, boiling in the core.
cooling water per hour is required and is taken from a river, or in the case of closed-circuit cooling operation, is derived from the cooling tower circuit.
The feed water is heated to a temperature of about 215°C by means of a heating system and refed into the reactor.
www.euronuclear.org /info/encyclopedia/boilingwaterreactor.htm   (264 words)

  
 math lessons - Pressurized water reactor
A pressurized water reactor (PWR) is a type of nuclear power reactor that uses ordinary light water for both coolant and for neutron moderator.
Another advantage of using coolant water as a moderator in a pressurized water reactor is that the moderating effect decreases as a function of temperature due to the negative temperature coefficient of reactivity.
A disadvantage is that the reactor is succeptible to produce power at rates that result in damage to fuel cells in the event of introduction of cold water into the reactor or in the event the secondary system experiences a steam rupture.
www.mathdaily.com /lessons/PWR   (919 words)

  
 Boiling Water Reactor (BWR)   (Site not responding. Last check: 2007-10-08)
BWR is the abbreviation for the Boiling Water Reactor.
The water then passes to the Feedwater Pumps which in turn, pump the water to the reactor and start the cycle all over again.
The BWR is unique in that the Control Rods, used to shutdown the reactor and maintain an uniform power distribution across the reactor, are inserted from the bottom by a high pressure hydraulically operated system.
www.nucleartourist.com /type/bwr.htm   (498 words)

  
 Light Water Nuclear Reactors
The nuclear fission reactors used in the United States for electric power production are classified as "light water reactors" in contrast to the "heavy water reactors" used in Canada.
Light water (ordinary water) is used as the moderator in U.S. reactors as well as the cooling agent and the means by which heat is removed to produce steam for turning the turbines of the electric generators.
The two varieties of the light water reactor are the pressurized water reactor (PWR) and boiling water reactor (BWR).
hyperphysics.phy-astr.gsu.edu /hbase/nucene/ligwat.html   (452 words)

  
 [No title]   (Site not responding. Last check: 2007-10-08)
A Boiling Water Reactor (BWR) is a nuclear reactor in which the design permits steam to be in contact with the nuclear fuel rods.
Water is pumped through the pipes past the fuel rods, which heat the water to boiling.
Thus the reactor is enclosed in an air-tight and water tight concrete shell.
www.ceet.niu.edu /faculty/vanmeer/NOTE-BWR.htm   (256 words)

  
 [No title]   (Site not responding. Last check: 2007-10-08)
In the BWR plant 10, the reactor coolant is converted to steam within the reactor vessel 12, the steam is then directed to turbine generators 14, is condensed, and fed back to the reactor vessel as feed water.
This recirculated water is directed via the recirculation pumps 22, at high pressure and velocity, to the jet pumps 24, which enhances the total flow of feed water through the jet pumps 24.
A jacking device for use in a boiling water reactor according to Claim 8, wherein each of said sloped side portions of said third member further comprise a projecting portion dimensioned so as to be inserted in one of said engagement slots.
www.wipo.int /cgi-pct/guest/getbykey5?KEY=00/62303.001019&ELEMENT_SET=DECL   (3401 words)

  
 TVA: Nuclear Energy   (Site not responding. Last check: 2007-10-08)
The heat from the water inside the tubes is transferred to the secondary source of water, which boils and turns to steam.
In the boiling water reactor design used at the Browns Ferry Nuclear Plant, steam is produced in the reactor core instead of in the steam generators.
The containment building, the reactor vessel, the fuel assemblies, and several other barriers are designed to contain radiation and protect plant workers and the public living near a nuclear plant from any exposure to elevated levels of radiation.
www.tva.gov /power/nuclear/howworks.htm   (866 words)

  
 Boiling water reactor at opensource encyclopedia   (Site not responding. Last check: 2007-10-08)
Since the water around the core of a reactor is always contaminated with traces of radionuclides, it means that the turbine must be shielded and radiological protection provided during maintenance.
Like the pressurized water reactor, the reactor core continues to produce heat from radioactive decay after the fission reactions have stopped, making nuclear meltdown possible in the event that all safety systems have failed and the core does not receive coolant.
A BWR fuel assembly comprises 90-100 fuel rods, and there are up to 750 assemblies in a reactor core, holding up to 140 tonnes of uranium.
www.wiki.tatet.com /Boiling_water_reactor.html   (223 words)

  
 Boiling-water reactor   (Site not responding. Last check: 2007-10-08)
The steam is condensed in the condenser which is cooled by sea water, river water, or water from a cooling tower.
The reactor's output is controlled by means of control rods inserted through the bottom of the reactor tank.
Boiling-water reactors in the west are provided with a leak-tight reactor containment and with safety systems that prevent the release of radioactive materials in an accident.
www.kose.ee /nucbasic/nucpedia/uk/boiling.htm   (254 words)

  
 Materials and Nuclear Power — Overview of Euromat 96
Light water reactors (the pressurised water reactor or PWR and the boiling water reactor or BWR) account for over 80% of an installed nuclear capacity, and thus materials aspects of these system were the dominant theme of Sessions 1 and 2.
Furthermore, in the latest on-going designs, such as the European pressurised water reactor (EPR) being undertaken by a FrancoGerman (Framatome/Siemens) consortium, the lifetime neutron dose even for a proposed extended 60 year life is significantly reduced compared with standard plant by specifying a larger than usual gap between the RPV and the core barrel.
The Cr-depleted boundary is susceptible to anodic dissolution in reactor water and, because the boundary is also weakened by segregants, a form of SCC occurs.
www.azom.com /details.asp?ArticleID=2139   (1484 words)

  
 [No title]   (Site not responding. Last check: 2007-10-08)
In order to assess boiling water reactor plant parameters and performance, a historical database of plant parameter and performance data is maintained and regularly updated.
For example, in a boiling water nuclear reactor, the determining of water chemistry characteristics including conductivity, key anionic species, radioactive products and the like is an important factor to assess plant parameters and predict reactor performance.
In a boiling water nuclear reactor, it is important to maintain and periodically sample water chemistry for characteristics such as conductivity, key species, radioactive products and the like.
www.wipo.int /cgi-pct/guest/getbykey5?KEY=01/97068.011220&ELEMENT_SET=DECL   (3112 words)

  
 ANL-W History - Reactors (BORAX-IV)   (Site not responding. Last check: 2007-10-08)
BORAX-IV The BORAX-IV reactor, which was the successor to BORAX III, began operation in December of 1956.
Subsequent operation of the reactor during the spring of 1958 was for the purpose of evaluating the effect of operating a direct-cycle boiling water reactor with a fuel element defect and for locating defective elements in the core.
The purpose of a group of tests, the BORAX-IV series, was to determine the response of a boiling water reactor to a low-thermal conductivity fuel having a long thermal time constant, as would be expected from oxide-fueled central station reactors.
www.anlw.anl.gov /anlw_history/reactors/borax_iv.html   (410 words)

  
 Glossary   (Site not responding. Last check: 2007-10-08)
A nuclear reactor that uses light water (H2O) as the primary coolant and moderator and slightly enriched uranium as the fuel.
A light-water reactor in which heat is transferred from the core to a heat exchanger via water kept under high pressure, so that high temperature can be maintained in the primary coolant system without boiling the water.
Irradiated reactor fuel that is discharged in one cycle and inserted in to the same reactor during a subsequent refueling.
web.em.doe.gov /glossary-r.html   (1198 words)

  
 BWRTT Boiling Water Reactor Turbine Trip
The magnitude of the neutron flux transient taking place in the BWR core is strongly affected by the initial rate of pressure rise caused by pressure oscillation and has a strong spatial variation.
The purpose of this proposal is to establish a BWR TT benchmark exercise, based on a well defined problem with complete set of input specifications and reference experimental data, for qualification of the coupled 3-D neutron kinetics/thermal-hydraulic system transient codes.
Option 1 of the second exercise is to perform a coupled 3-D kinetics/thermal-hydraulic calculation for the reactor core using the PSU-provided boundary conditions at core inlet and exit.
www.nea.fr /html/science/egrsltb/bwrttb   (1222 words)

  
 Nuclear-- Boiling Water Reactor   (Site not responding. Last check: 2007-10-08)
The unused steam is exhausted to the condenser where it is condensed into water.
The resulting water is pumped out of the condenser with a series of pumps, reheated, and pumped back to the reactor vessel.
The reactor's core contains fuel assemblies which are cooled by water, which is force-circulated by electrically powered pumps.
www.eia.doe.gov /cneaf/nuclear/page/nuc_reactors/bwr.html   (83 words)

  
 Nuclear Power Notes
A pressurized Water reactor (PWR) is characterized by having the core immersed in water in a large steel tank.
Water in the secondary loop is allowed to boil in a steam generator tank (not shown).
As the damaged reactor was brought undercontroll, it was known from radiation monitoring that there was asignificantt amount of radioactive material in the bottom of the pressure vessel.
www.ceet.niu.edu /faculty/vanmeer/nuc.htm   (3089 words)

  
 New Page 4   (Site not responding. Last check: 2007-10-08)
There are two types of power plants one is the pressurized water reactor and the other is a Boiling water reactor.
First the fuel is put into the reactor and a single neutron is shot at the fuel and a Chain reaction occurs.
By that I mean the water is introduced directly into the rector or the reactor pipes run by water pipes (not actually mixing the water with the reaction chamber water.) The top right is a Pressurized Water Reactor (PWR) and to the top left is a Boiling Water Reactor (BWR).
www.personal.psu.edu /users/j/s/jsm290/reaction.html   (385 words)

  
 INSC: Database   (Site not responding. Last check: 2007-10-08)
Reactor control is performed by 16 shim rods and 3 safety rods.
An experimental power plant with the vessel-type boiling-water reactor VK-50 has been designed to study the operational parameters and performance of one-circuit nuclear power stations, with steam supplied directly from a reactor to a turbine.
In particular, a wide range of experiments investigating the neutron-physical and thermohydraulic characteristics of a reactor, the performance of the main equipment, radiation and technical safety, water conditions, corrosion resistance of various structural materials, the performance of fuel subassemblies, etc.
www.insc.anl.gov /cgi-bin/sql_interface?view=rx_com_matrix&qvar=unit&qval=531   (335 words)

  
 USATODAY.com - Few differences for new nuclear plants   (Site not responding. Last check: 2007-10-08)
This has a 1,500 megawatt boiling water design, meaning the cooling water is not under pressure and is allowed to boil with steam passing over the top of the reactor into the turbines.
They produce more heat and less waste with different cooling mechanisms than the light water reactors, and would be able to produce hydrogen as a replacement for fossil fuels to power everything from cars to electric lamps.
A gas-cooled reactor known as the pebble bed is being developed in South Africa and was touted for the U.S. market until Exelon, the Chicago-based utility, pulled out of the project.
www.usatoday.com /tech/science/2005-06-11-nukes_x.htm   (787 words)

  
 Nuclear Power Reactors   (Site not responding. Last check: 2007-10-08)
Heat is produced in a nuclear reactor when neutrons strike Uranium atoms causing them to fission in a continuous chain reaction.
In a PWR, the heat is removed from the reactor by water flowing in a closed pressurized loop.
The second loop is kept at a lower pressure, allowing the water to boil and create steam, which is used to turn the turbine-generator and produce electricity.
reactor.engr.wisc.edu /power.html   (433 words)

  
 ANL-W History - Reactors (BORAX-V)   (Site not responding. Last check: 2007-10-08)
In 1958, a proposal to construct an extremely flexible boiling water reactor was submitted.
The reactor demonstrated that improved efficiency from manufactured steam is obtainable by incorporating a number of superheat fuel assemblies in the reactor core lattice.
This raises the temperature of saturated steam from 489°F in the core to 850°F of dry steam and raises the pressure to 600 psig in the superheat portion of the reactor.
www.anlw.anl.gov /anlw_history/reactors/borax_v.html   (353 words)

  
 Vallecitos/First of a breed: The Vallecitos boiling water reactor in Pleasanton, Calif., became the first nuclear ...   (Site not responding. Last check: 2007-10-08)
Vallecitos/First of a breed: The Vallecitos boiling water reactor in Pleasanton, Calif., became the first nuclear generating station to be privately owned.
First of a breed: The Vallecitos boiling water reactor in Pleasanton, Calif., became the first nuclear generating station to be privately owned.
The Vallecitos boiling water reactor in Pleasanton, Calif., the first privately owned, nuclear-fueled generating station to contribute electricity to the grid, went online in 1957 and operated until 1963.
www.nukeworker.com /pictures/displayimage_154_0.html   (229 words)

  
 Modifications To Boiling Water Reactor Control Rod Drive Systems
Gridley: Since the initial discovery of cracking in boiling water reactor (BWR) control rod drive return line (CRDRL) nozzles in early 1977, General Electric (GE) has proposed a number of solutions to the problem in the course of which several documents wert submitted for NRC staff review.
During this incident the reactor vessel also was isolated from other sources of high pressure water and the CRD system makeup capability helped prevent uncovering of the active fuel.
When faced with the need to maintain water level upon loss of other capable high pressure water injection systems, the operator simply cannot be burdened with the need to refer to pump curves or the need to consider what, if any, other portions of system flow are not included in a respanned flow meter.
www.nrc.gov /reading-rm/doc-collections/gen-comm/gen-letters/1980/gl80029.html   (2151 words)

  
 EPRI: Boiling Water Reactor Chemistry Performance Monitoring Report - 2005 Edition
Successful operation of a nuclear plant demands careful monitoring of water chemistry, particularly in boiling water reactors, where control of iron and copper in the reactor coolant is essential.
This report compiles recent boiling water reactor (BWR) plant experience with these various chemistries and reviews the comparative performance and properties of the three types of BWR condensate polishing systems.
BWR water chemistry has evolved from essentially pure, relatively oxidizing water to the current programs, which include hydrogen addition for IGSCC mitigation, depleted zinc oxide (DZO) addition to minimize shutdown dose rates, and NMCA to minimize main steam operating dose rates.
www.epri.com /OrderableitemDesc.asp?product_id=000000000001009932&searchdate=12/05/2005   (735 words)

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