Generation IV Reactor - Wikipedia, The Free Encyclopedia

Generation IV reactorFrom Wikipedia, the free encyclopedia

Generation IV reactors (GenIV) are a set of theoreticalnuclear reactor designs currentlybeing researched. Most of thesedesigns are generally notexpected to be available forcommercial construction before2030. Current reactors inoperation around the world aregenerally considered second- orthird-generation systems, withmost of the first-generationsystems having been retired sometime ago. Generation V reactorsrefer to reactors that may bepossible but are not yetconsidered feasible, and are not actively being developed.

Contents

1 Reactor types1.1 Thermal reactors

1.1.1 Very-high-temperature reactor (VHTR)1.1.2 Molten-salt reactor (MSR)1.1.3 Supercritical-water-cooled reactor (SCWR)

1.2 Fast reactors1.2.1 Gas-cooled fast reactor (GFR)1.2.2 Sodium-cooled fast reactor (SFR)1.2.3 Lead-cooled fast reactor (LFR)

2 Advantages and disadvantages3 Participating countries4 Designs under development5 See also6 References7 External links

Reactor types

Many reactor types were considered initially; however, the list was downsized to focus on the most promisingtechnologies and those that could most likely meet the goals of the Gen IV initiative. Three systems arenominally thermal reactors and three are fast reactors. The Very High Temperature Reactor (VHTR) is alsobeing researched for potentially providing high quality process heat for hydrogen production. The fast reactorsoffer the possibility of burning actinides to further reduce waste and of being able to "breed more fuel" than

Generation IV reactor - Wikipedia, the free encyclopedia http://en.wikipedia.org/wiki/Generation_IV_reactor

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Very-High-Temperature Reactor(VHTR)

Molten Salt Reactor (MSR)

they consume. These systems offer significant advances in sustainability, safety and reliability, economics,proliferation resistance(depending on perspective) and physical protection.

Thermal reactors

A thermal reactor is a nuclear reactor that uses slow or thermal neutrons. A neutron moderator is used to slowthe neutrons emitted by fission to make them more likely to be captured by the fuel.

Very-high-temperature reactor (VHTR)

Main article: Very high temperature reactorSee also: Fort St. Vrain Generating Station, HTTR, and HTR-10

The very high temperature reactor concept uses a graphite-moderatedcore with a once-through uranium fuel cycle, using helium or molten saltas the coolant. This reactor design envisions an outlet temperature of1,000 °C. The reactor core can be either a prismatic-block or a pebblebed reactor design. The high temperatures enable applications such asprocess heat or hydrogen production via the thermochemical iodine-sulfur process. It would also be passively safe.

The planned construction of the first VHTR, the South African PBMR(pebble bed modular reactor), lost government funding in February, 2010.[1] A pronounced increase of costs andconcerns about possible unexpected technical problems had discouraged potential investors and customers.

The Peoples Republic of China began construction of a 200-MWe High Temperature Pebble bed reactor in 2012as a successor to its HTR-10.[2]

Also in 2012, as part of the Next Generation Nuclear Plant competition, Idaho National Laboratory approved adesign similar to Areva's prismatic block Antares reactor (http://de.areva.com/EN/areva-germany-312/future-reactor-concepts.html) as the chosen HTGR to be deployed as a prototype by 2021. It was in competition withGeneral Atomics' Gas turbine modular helium reactor and Westinghouse' Pebble Bed Modular Reactor.[3]

Molten-salt reactor (MSR)

Main article: Molten salt reactorSee also: Liquid fluoride thorium reactor

A molten salt reactor[4] is a type of nuclear reactor where the primarycoolant, or even the fuel itself is a molten salt mixture. There have beenmany designs put forward for this type of reactor and a few prototypesbuilt. The early concepts and many current ones rely on nuclear fueldissolved in the molten fluoride salt as uranium tetrafluoride (UF4) orthorium tetrafluoride (ThF4). The fluid would reach criticality by flowinginto a graphite core which would also serve as the moderator. Manycurrent concepts rely on fuel that is dispersed in a graphite matrix withthe molten salt providing low pressure, high temperature cooling.

The Gen IV MSR is more accurately termed an epithermal reactor than a thermal reactor due to the average


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Supercritical-Water-Cooled Reactor(SCWR)

speed of the neutrons that would cause the fission events within its fuel being faster than thermal neutrons.[5]

The principle of a MSR can be used for thermal, epithermal and fast reactors. Since 2005 the focus has movedtowards a fast spectrum MSR (MSFR). [6]

Supercritical-water-cooled reactor (SCWR)

Main article: Supercritical water reactor

The supercritical water reactor (SCWR)[4] is a reduced moderationwater reactor concept that, due to the average speed of the neutrons thatwould cause the fission events within the fuel being faster than thermalneutrons, it is more accurately termed an epithermal reactor than athermal reactor. It uses supercritical water as the working fluid. SCWRsare basically light water reactors (LWR) operating at higher pressure andtemperatures with a direct, once-through heat exchange cycle. As mostcommonly envisioned, it would operate on a direct cycle, much like aboiling water reactor (BWR), but since it uses supercritical water (not tobe confused with critical mass) as the working fluid, it would have onlyone water phase present, which makes the supercritical heat exchangemethod more similar to a pressurized water reactor (PWR). It couldoperate at much higher temperatures than both current PWRs and BWRs.

Supercritical water-cooled reactors (SCWRs) are promising advanced nuclear systems because of their highthermal efficiency (i.e., about 45% vs. about 33% efficiency for current LWRs) and considerable plantsimplification.

The main mission of the SCWR is generation of low-cost electricity. It is built upon two proven technologies,LWRs, which are the most commonly deployed power generating reactors in the world, and supercritical fossilfuel fired boilers, a large number of which are also in use around the world. The SCWR concept is beinginvestigated by 32 organizations in 13 countries.[citation needed]

Fast reactors

A fast reactor directly uses the fast neutrons emitted by fission, without moderation. Unlike thermal neutronreactors, fast neutron reactors can be configured to "burn", or fission, all actinides, and given enough time,therefore drastically reduce the actinides fraction in spent nuclear fuel produced by the present world fleet ofthermal neutron Light Water Reactors, thus closing the Nuclear fuel cycle. Alternatively, if configureddifferently, they can also breed more actinide fuel than they consume.

Gas-cooled fast reactor (GFR)

Main article: Gas-cooled fast reactor

The gas-cooled fast reactor (GFR)[4] system features a fast-neutron spectrum and closed fuel cycle forefficient conversion of fertile uranium and management of actinides. The reactor is helium-cooled and with anoutlet temperature of 850 °C it is an evolution of the Very High Temperature Reactor(VHTR) to a moresustainable fuel cycle. It will use a direct Brayton cycle gas turbine for high thermal efficiency. Several fuelforms are being considered for their potential to operate at very high temperatures and to ensure an excellent


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Gas-Cooled Fast Reactor (GFR)

Pool design Sodium-Cooled FastReactor (SFR)

retention of fission products: composite ceramic fuel, advanced fuelparticles, or ceramic clad elements of actinide compounds. Coreconfigurations are being considered based on pin- or plate-based fuelassemblies or prismatic blocks.

The European Sustainable Nuclear Industrial Initiative is funding threeGeneration IV reactor systems, one of which is a gas-cooled fast reactor,called Allegro, 100 MW(t), which will be built in a central or easternEuropean country with construction expected to begin in 2018.[7] Thecentral European Visegrád Group are committed to pursuing thetechnology.[8] In 2013 German, British, and French institutes finished a3 year collaboration study on the follow on industrial scale design,known as GoFastR.[9] They were funded by the EU's 7th FWPframework programme, with the goal of making a sustainable VHTR.[10]

Sodium-cooled fast reactor (SFR)

Main article: Sodium-cooled fast reactor

See also: Experimental Breeder Reactor II, S-PRISM, BN-600reactor, and Toshiba 4S

The SFR[4] is a project that builds on two closely related existingprojects, the liquid metal fast breeder reactor and the Integral FastReactor.

The goals are to increase the efficiency of uranium usage by breedingplutonium and eliminating the need for transuranic isotopes ever to leavethe site. The reactor design uses an unmoderated core running on fastneutrons, designed to allow any transuranic isotope to be consumed (andin some cases used as fuel). In addition to the benefits of removing the long half-life transuranics from the wastecycle, the SFR fuel expands when the reactor overheats, and the chain reaction automatically slows down. Inthis manner, it is passively safe.

The SFR reactor concept is cooled by liquid sodium and fueled by a metallic alloy of uranium and plutonium orspent nuclear fuel, the "nuclear waste" of Light Water Reactors. The SFR fuel is contained in steel cladding withliquid sodium filling in the space between the clad elements which make up the fuel assembly. One of the designchallenges of an SFR is the risks of handling sodium, which reacts explosively if it comes into contact withwater. However, the use of liquid metal instead of water as coolant allows the system to work at atmosphericpressure, reducing the risk of leakage.

The European Sustainable Nuclear Industrial Initiative is funding three Generation IV reactor systems, one ofwhich is a sodium-cooled fast reactor, called ASTRID, Advanced Sodium Technical Reactor for IndustrialDemonstration, EDF and Areva are leading the design with British collaboration.[11][12] Astrid will be ratedabout 600 MWe and is expected to be built in France, with construction slated to begin in 2017 near to thePhénix reactor.[7]

The PRC's first commercial-scale, 800 MWe, fast neutron reactor, to be situated near Sanming city in Fujianprovince will be a SFR. In 2009 an agreement was signed that would entail the Russian BN-800 reactor designto be sold to the PRC once it is completed, this would be the first time commercial-scale fast neutron reactors


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Lead-Cooled Fast Reactor (LFR)

have ever been exported.[13]

In India, the Prototype Fast Breeder Reactor, a 500MWe Sodium cooled fast reactor is under construction, witha completion year of 2014/2015.

Lead-cooled fast reactor (LFR)

Main article: Lead-cooled fast reactorSee also: MYRRHA and BREST-300

The lead-cooled fast reactor[4] features a fast-neutron-spectrum lead orlead/bismuth eutectic (LBE) liquid-metal-cooled reactor with a closedfuel cycle. Options include a range of plant ratings, including a "battery"of 50 to 150 MW of electricity that features a very long refuelinginterval, a modular system rated at 300 to 400 MW, and a largemonolithic plant option at 1,200 MW. (The term battery refers to thelong-life, factory-fabricated core, not to any provision forelectrochemical energy conversion.) The fuel is metal or nitride-basedcontaining fertile uranium and transuranics. The LFR is cooled bynatural convection with a reactor outlet coolant temperature of 550 °C,possibly ranging up to 800 °C with advanced materials. The higher temperature enables the production ofhydrogen by thermochemical processes.

The European Sustainable Nuclear Industrial Initiative is funding three Generation IV reactor systems, one ofwhich is a lead-cooled fast reactor that is also an Accelerator-driven sub-critical reactor, called Myrrha, 100MW(t), which will be built in Belgium with construction expected to begin after 2014 and the industrial scaleversion, known as Alfred, slated to be constructed sometime after 2017. A reduced-power model of Myrrhacalled Guinevere was started up at Mol in March 2009.[7]

Advantages and disadvantages

Relative to current nuclear power plant technology, the claimed benefits for 4th generation reactors include:

Nuclear waste that remains radioactive for a few centuries instead of millennia [14]

100-300 times more energy yield from the same amount of nuclear fuel [15]

The ability to consume existing nuclear waste in the production of electricityImproved operating safety

Nuclear reactors do not emit CO2 during operation, although like all low carbon power sources, the mining andconstruction phase can result in CO2 emissions, if energy sources which are not carbon neutral (such as fossilfuels), or CO2 emitting cements are used during the construction process. A 2012 Yale University reviewpublished in the Journal of Industrial Ecology analyzing CO2 life cycle assessment(LCA) emissions from nuclearpower determined that:[16]

"The collective LCA literature indicates that life cycle GHG [ greenhouse gas ] emissions fromnuclear power are only a fraction of traditional fossil sources and comparable to renewabletechnologies."

Although the paper primarily dealt with data from Generation II reactors, and did not analyze the CO2 emissions


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by 2050 of the presently under construction Generation III reactors, it did summarize the Life Cycle Assessmentfindings of in development reactor technologies.

FBRs [ Fast Breeder Reactors ] have been evaluated in the LCA literature. The limited literaturethat evaluates this potential future technology reports median life cycle GHG emissions... similarto or lower than LWRs[ Gen II light water reactors ] and purports to consume little or no uraniumore.

One disadvantage of any new reactor technology is that safety risks may be greater initially as reactor operatorshave little experience with the new design. Nuclear engineer David Lochbaum has explained that almost allserious nuclear accidents have occurred with what was at the time the most recent technology. He argues that"the problem with new reactors and accidents is twofold: scenarios arise that are impossible to plan for insimulations; and humans make mistakes". Dennis Berry, Director Emeritus of Sandia National Laboratories said"fabrication, construction, operation, and maintenance of new reactors will face a steep learning curve:advanced technologies will have a heightened risk of accidents and mistakes. The technology may be proven,but people are not".[17]

A specific risk of the sodium-cooled fast reactor is related to using metallic sodium as a coolant. In case of abreach, sodium explosively reacts with water. Fixing breaches may also prove dangerous, as the cheapest noblegas argon is also used to prevent sodium oxidation. Argon, like helium, can displace oxygen in the air and canpose hypoxia concerns, so workers may be exposed to this additional risk. This is a pertinent problem as can betestified by the events at the loop type Prototype Fast Breeder Reactor Monju at Tsuruga, Japan.[18] Using leador molten salts mitigates this problem by making the coolant less reactive and allowing a high freezingtemperature and low pressure in case of a leak.

In many cases, there is already a large amount of experience built up with numerous proof of concept Gen IVdesigns. For example, the reactors at Fort St. Vrain Generating Station and HTR-10 are similar to the proposedGen IV VHTR designs, and the pool type EBR-II, Phénix and BN-600 reactor are similar to the proposed pooltype Gen IV Sodium Cooled Fast reactors being designed.

Participating countries

The members of the Generation IV International Forum (GIF) are:

Argentina [2] (http://www.cnea.gov.ar/) (Spanish-only web site) Brazil [3] (http://www.aben.com.br/) Canada [4] (http://www.aecl.ca/) China [5] (http://www.caea.gov.cn/n602669/n2231600/n2272156/n2272415/167948.html) European Union [6] (http://www.euronuclear.org/1-information/generation-IV.htm) France [7] (http://www.cea.fr/) Japan [8] (http://www.jaea.go.jp/english/) South Korea [9] (http://www.mest.go.kr/index.html) (Korean-only web site) Russia [10] (http://www.rosatom.ru/en/) South Africa [11] (http://www.eskom.co.za/live/index.php)

Switzerland [12] (http://www.psi.ch/index_e.shtml) United Kingdom [13] (http://www.dti.gov.uk/energy/sources/nuclear/technology/fission

/page17924.html) United States [14] (http://nuclear.energy.gov/genIV/neGenIV1.html)

The nine GIF founding members were joined by Switzerland in 2002, Euratom in 2003 and most recently by


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China and Russia at the end of 2006.[19]

Australia has also shown interest in joining the GIF.[citation needed]

The 36th GIF meeting in Brussels was held in November 2013.[20]

Designs under development

VVER-1700/393 (VVER-SCWR or VVER-SKD) — a Russian Supercritical-water-cooled reactor withdouble-inlet-core and a breeding ratio of 0.95.SVBR-100 a modular 100MWe lead-bismuth cooled fast neutron reactor concept designed by OKBGidropress in Russia.BREST-OD-300 (Lead-cooled fast reactor) 300 MWe, to be developed after the SVBR-100, and builtover 2016-20 it will dispense with the fertile blanket around the core and will supersede the sodiumcooled BN-600 reactor design, to give enhanced proliferation resistance.[21]

See also

Nuclear reactorNuclear materialNuclear physicsList of reactor types

Generation II reactorGeneration III reactorIntegral Fast Reactor

Liquid fluoride thoriumreactorBreeder reactorSmall modular reactor

References^ South Africa to stop funding Pebble Bed nuclear reactor (http://www.powergenworldwide.com/index/display/articledisplay/6322207443/articles/power-engineering-international/volume-18/Issue_3/regulars/world-news/INTERNATIONAL.html)

1.

^ Nucnet Report: 'China Begins Construction of First Generation IV HTR-PM Unit', 7 January 2013(http://www.nucnet.org/all-the-news/2013/01/07/china-begins-construction-of-first-generation-iv-htr-pm-unit)

2.

^ "INL approves Antares design" (http://www.world-nuclear-news.org/NN-Areva_modular_reactor_selected_for_NGNP_development-1502124.html).

3.

^ a b c d e US DOE Nuclear Energy Research Advisory Committee (2002). A Technology Roadmap for GenerationIV Nuclear Energy Systems (http://nuclear.energy.gov/genIV/documents/gen_iv_roadmap.pdf). GIF-002-00.

4.

^ "Idaho National Laboratory detailing some current efforts at developing Gen. IV reactors" (https://inlportal.inl.gov/portal/server.pt?open=514&objID=1361&parentname=CommunityPage&parentid=10&mode=2&in_hi_userid=200&cached=true).

5.

^ H. Boussier, S. Delpech, V. Ghetta et Al. : The Molten Salt Reactor (MSR) in Generation IV: Overview andPerspectives, GIF SYMPOSIUM PROCEEDINGS/2012 ANNUAL REPORT, NEA No. 7141, pp95 [1](https://www.gen-4.org/gif/jcms/c_44720/annual-reports)

6.

^ a b c "The European Sustainable Nuclear Industrial Initiative (ESNII) will support three Generation IV reactorsystems: a sodium-cooled fast reactor, or SFR, called Astrid that is proposed by France; a gas-cooled fast reactor,GFR, called Allegro supported by central and eastern Europe; and a lead-cooled fast reactor, LFR, technology pilotcalled Myrrha that is proposed by Belgium." (https://www.euronuclear.org/1-information/news/Gen-IV.htm).

7.

^ "The V4G4 Centre of Excellence for performing joint research, development and innovation in the field ofGeneration-4 (G4) nuclear reactors have been established. 20 July 2013 National Center for Nuclear Research(NCBJ]" (http://www.alphagalileo.org/ViewItem.aspx?ItemId=133111&CultureCode=en).

8.

^ "the European Gas cooled Fast Reactor." (http://www.ist-world.org/ProjectDetails.aspx?ProjectId=5cb8f3f283574cc6b2bdbf72533172d8).

9.


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^ "The GOFASTR research program" (http://www.2020-horizon.com/GOFASTR-European-Gas-Cooled-Fast-Reactor%28GOFASTR%29-s312.html).

10.

^ "Areva, CEA secure EUR650m funding to develop ASTRID sodium-cooled Generation IV reactor 11/11/2010"(http://www.power-eng.com/articles/2010/11/areva--cea-secure.html).

11.

^ "UK and France Sign Landmark Civil Nuclear Cooperation Agreement 02/22/2012 . POWERnews"(http://www.powermag.com/uk-and-france-sign-landmark-civil-nuclear-cooperation-agreement/).

12.

^ "Joint venture launched for Chinese fast reactor" (http://www.world-nuclear-news.org/C-Joint_venture_launched_for_Chinese_fast_reactor-3004104.html).

13.

^ "Strategies to Address Global Warming" (http://www.columbia.edu/~jeh1/mailings/2009/20090713_Strategies.pdf).

14.

^ "4th Generation Nuclear Power" (http://www.ossfoundation.us/projects/energy/nuclear).15.^ Warner, Ethan S.; Heath, Garvin A. Life Cycle Greenhouse Gas Emissions of Nuclear Electricity Generation:Systematic Review and Harmonization (http://onlinelibrary.wiley.com/doi/10.1111/j.1530-9290.2012.00472.x/full),Journal of Industrial Ecology, Yale University, published online April 17, 2012, doi:10.1111/j.1530-9290.2012.00472.x.

16.

^ "Is Fukushima the new normal for nuclear reactors?" (http://theconversation.com/is-fukushima-the-new-normal-for-nuclear-reactors-17391).

17.

^ Tabuchi, Hiroko (17 June 2011). "Japan Strains to Fix a Reactor Damaged Before Quake"(http://www.nytimes.com/2011/06/18/world/asia/18japan.html). The New York Times.

18.

^ Commissariat à l'Énergie Atomique. "Future nuclear systems" (http://nucleaire.cea.fr/fr/nucleaire_futur/pu_schema1ch2.htm).

19.

^ "The Generation IV international forum holds their 36th meeting on Monday 18th Nov 2013 in Brussels."(http://events.r20.constantcontact.com/register/event?llr=mscrkjkab&oeidk=a07e7melf609716b2c6).

20.

^ "Technology Developments & Plant Efficiency for the Russian Nuclear Power Generation Market Wednesday"(http://www.powertecrussia.com/blog/tag/nuclear-power/). March 24, 2010.

21.

External links

Article from Idaho National Laboratory detailing some current efforts at developing Gen. IV reactors.(https://inlportal.inl.gov/portal/server.pt?open=514&objID=1361&parentname=CommunityPage&parentid=10&mode=2&in_hi_userid=200&cached=true)Generation IV International Forum (GIF) (http://www.gen-4.org/)U.S. Department of Energy Office of Nuclear Energy, Science and Technology (http://nuclear.energy.gov/genIV/neGenIV1.html)Gen IV presentation (http://www.engr.utk.edu/nuclear/colloquia/slides/Gen%20IV%20U-Tenn%20Presentation.pdf)Science or Fiction - Is there a Future for Nuclear? (http://www.ecology.at/ecology/files/pr577_1.pdf)(Nov. 2007) - A publication from the Austrian Ecology Institute about 'Generation IV' and Fusionreactors.Gail H. Marcus (December 2011). "Nuclear Power After Fukushima" (http://memagazine.asme.org/Articles/2011/December/Nuclear_Power_After_Fukushima.cfm). Mechanical Engineering (themagazine of ASME). Retrieved 23 January 2012. "In the wake of a severe plant accident, advancedreactor designs are getting renewed attention."International Thorium Energy Organisation - www.IThEO.org (http://www.itheo.org/)

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Generation IV Reactor - Wikipedia, The Free Encyclopedia

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