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Изследователски реактор Изследователски реактор е ядрен реактор, който се използва за научни цели, а не за производство на енергия (като в атомните електроцентрали), за производство на радиоактивни материали за направата на ядрено оръжие, или за задвижване на превозно средство (например атомна подводница). [редактиране] Техническа характеристика Изследователските реактори имат по-малка мощност от тази на реакторите с друго предназначение. Докато един типичен реактор за производство на електричество има топлинна мощност от 3 000 MW (мегавата), изследователските реактори имат мощност между 10 киловата и 10 мегавата. Обединената топлинна мощност на всички 283 изследователски реактора по света е малко над 3 000 MW. Изследователските реактори са по-прости и работят при по-ниски температури. Нуждаят се от по-малко гориво и при "изгарянето" му се натрупват по-малко продукти на разпада. От друга страна, горивото им обикновено е по-силно обогатен уран, обикновено до 20% уран-235, въпреки че някои използват гориво с 93% уран-235. Освен това, голямото съотношение на обем и мощност в ядрото изисква специални похвати в проектирането им. Както и при реакторите за други цели, ядрото се нуждае от охлаждане, което обикновено се постига чрез естествена или принудителна конвекция с вода, както и от неутронен забавител, който да забавя неутроните и реакцията на разпад.
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Research reactor Research reactors are nuclear reactors that serve primarily as a neutron source. They are also called non-power reactors, in contrast to power reactors that are used for electricity production, heat generation, or maritime propulsion. Purpose[edit] The neutrons produced by a research reactor are used for neutron scattering, non-destructive testing, analysis and testing of materials, production of radioisotopes, research and public outreach and education. Research reactors that produce radioisotopes for medical or industrial use are sometimes called isotope reactors. Reactors that are optimised for beamline experiments nowadays compete with spallation sources. Technical aspects[edit] Research reactors are simpler than power reactors and operate at lower temperatures. They need far less fuel, and far less fission products build up as the fuel is used. On the other hand, their fuel requires more highly enriched uranium, typically up to 20% U-235,[1] although some use 93% U-235; while 20% enrichment is not generally considered usable in nuclear weapons, 93% is commonly referred to as "weapons-grade". They also have a very high power density in the core, which requires special design features. Like power reactors, the core needs cooling, typically natural or forced convection with water, and a moderator is required to slow the neutron velocities and enhance fission. As neutron production is their main function, most research reactors benefit from reflectors to reduce neutron loss from the core. Conversion to low enriched uranium[edit] The International Atomic Energy Agency and the U.S. Department of Energy initiated a program in 1978 to develop the means to convert research reactors from using highly enriched uranium (HEU) to the use of low enriched uranium (LEU), in support of its nonproliferation policy.[2][3] By that time, the U.S. had supplied research reactors and highly enriched uranium to 41 countries as part of its Atoms for Peace program. In 2004, the U.S. Department of Energy extended its Foreign Research Reactor Spent Nuclear Fuel Acceptance program until 2019.[4] As of 2016, a National Academies of Sciences, Engineering, and Medicine report concluded converting all research reactors to LEU cannot be completed until 2035 at the earliest. In part this is because the development of reliable LEU fuel for high neutron flux research reactors, that does not fail through swelling, has been slower than expected.[5] As of 2020[update], 72 HEU research reactors remain.[6] Designers and constructors[edit] While in the 1950s, 1960s and 1970s there were a number of companies that specialized in the design and construction of research reactors, the activity of this market cooled down afterwards, and many companies withdrew. The market has consolidated today into a few companies that concentrate the key projects on a worldwide basis. The most recent international tender (1999) for a research reactor was that organized by the Australian Nuclear Science and Technology Organisation for the design, construction and commissioning of the Open-pool Australian lightwater reactor (OPAL). Four companies were prequalified: Atomic Energy of Canada Limited (AECL), INVAP, Siemens and Technicatom. The project was awarded to INVAP that built the reactor. In recent years, AECL withdrew from this market, and Siemens and Technicatom activities were merged into Areva. Classes of research reactors[edit] - Aqueous homogeneous reactor - Argonaut class reactor - DIDO class, six high-flux reactors worldwide - TRIGA, a highly successful class with >50 installations worldwide - SLOWPOKE reactor class, developed by AECL, Canada - Miniature neutron source reactor, based on the SLOWPOKE design, developed by AECL, currently exported by China Research centers[edit] A complete list can be found at the List of nuclear research reactors. Research centers that operate a reactor: Decommissioned research reactors: References[edit] - ^ Alrwashdeh, Mohammad, and Saeed A. Alameri. "Reactor Monte Carlo (RMC) model validation and verification in compare with MCNP for plate-type reactor." - ^ "CRP on Conversion of Miniature Neutron Source Research Reactors (MNSR) to Low Enriched Uranium (LEU)". Nuclear Fuel Cycle & Waste Technology. International Atomic Energy Agency. 13 January 2014. Archived from the original on Jun 12, 2018. Retrieved 25 October 2015. - ^ "Reduced Enrichment for Research and Test Reactors". National Nuclear Security Administration. Archived from the original on 29 October 2004. - ^ "U.S. Foreign Research Reactor Spent Nuclear Fuel Acceptance". National Nuclear Security Administration. Archived from the original on 22 September 2006. - ^ Cho, Adrian (28 January 2016). "Ridding research reactors of highly enriched uranium to take decades longer than projected". Science. Retrieved 13 April 2020. - ^ "IAEA highlights work to convert research reactors". World Nuclear News. 24 February 2020. Retrieved 13 April 2020. - ^ a b c "Budapest Research Reactor | Budapest Neutron Centre ...for research, science and innovation!". www.bnc.hu. - ^ "Institute for Nuclear Technology". reak.bme.hu. - ^ "Nuclear Reactors". pd.chem.ucl.ac.uk. - ^ a b "RA-6 de Argentina" (in European Spanish). - ^ "Research reactors - Canadian Nuclear Association". Canadian Nuclear Association. - ^ "High Flux Reactor - European Commission". ec.europa.eu. 13 February 2013. {{cite web}}: CS1 maint: url-status (link) - ^ Mainz, Johannes Gutenberg-Universität. "Reactor". www.kernchemie.uni-mainz.de (in German). - ^ a b "ATI : Reactor". ati.tuwien.ac.at. - ^ a b c "The reactor | National Research Nuclear University MEPhI". eng.mephi.ru. - ^ a b "SAFARI-1". www.necsa.co.za. - ^ a b "High-Flux Advanced Neutron Application Reactor (HANARO) | Facilities | NTI". www.nti.org. - ^ a b "Research Reactor LVR-15 | Centrum výzkumu Řež". cvrez.cz. - ^ a b "History - Nuclear Reactor Program". Nuclear Reactor Program. - ^ "ATR Factsheet" (PDF). Idaho National Laboratory. Archived from the original (PDF) on 2008-07-03. - ^ a b "Maryland University Training Reactor (MUTR) | 250 kW TRIGA Reactor | University of Maryland Radiation Facilities". radiation.umd.edu/. - ^ "Nuclear Science Center Washington State University". nsc.wsu.edu. - ^ "Research Reactor Database - GHARR-1". International Atomic Energy Agency. Retrieved February 15, 2018. - ^ "Winfrith's DRAGON loses its fire". www.nda.gov.uk. Archived from the original on 6 October 2012. Retrieved 12 January 2022. - ^ a b Karlsen, Wade; Vilkamo, Olli (2016-12-14). "Finland's old nuclear research reactor to be decommissioned – New Centre for Nuclear Safety under construction". VTT Impulse. - ^ "Research Reactor Database". International Atomic Energy Agency. - WNA Information Paper # 61: Research Reactors - Nuclear Nonproliferation: DOE Needs to Take Action to Further Reduce the Use of Weapons-Usable Uranium in Civilian Research Reactors, GAO, July 2004, GAO-04-807