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Research reactors are
nuclear fission Nuclear fission is a reaction in which the nucleus of an atom splits into two or more smaller nuclei. The fission process often produces gamma photons, and releases a very large amount of energy even by the energetic standards of radio ...
-based
nuclear reactor A nuclear reactor is a device used to initiate and control a fission nuclear chain reaction or nuclear fusion reactions. Nuclear reactors are used at nuclear power plants for electricity generation and in nuclear marine propulsion. Heat fr ...
s that serve primarily as a
neutron source A neutron source is any device that emits neutrons, irrespective of the mechanism used to produce the neutrons. Neutron sources are used in physics, engineering, medicine, nuclear weapons, petroleum exploration, biology, chemistry, and nuclear p ...
. They are also called non-power reactors, in contrast to power reactors that are used for
electricity production Electricity generation is the process of generating electric power from sources of primary energy. For utilities in the electric power industry, it is the stage prior to its delivery (transmission, distribution, etc.) to end users or its storag ...
, heat generation, or maritime propulsion.


Purpose

The
neutron The neutron is a subatomic particle, symbol or , which has a neutral (not positive or negative) charge, and a mass slightly greater than that of a proton. Protons and neutrons constitute the nuclei of atoms. Since protons and neutrons beh ...
s produced by a research reactor are used for
neutron scattering Neutron scattering, the irregular dispersal of free neutrons by matter, can refer to either the naturally occurring physical process itself or to the man-made experimental techniques that use the natural process for investigating materials. Th ...
, non-destructive testing, analysis and testing of materials, production of
radioisotope A radionuclide (radioactive nuclide, radioisotope or radioactive isotope) is a nuclide that has excess nuclear energy, making it unstable. This excess energy can be used in one of three ways: emitted from the nucleus as gamma radiation; transferr ...
s, 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 In accelerator physics, a beamline refers to the trajectory of the beam of particles, including the overall construction of the path segment (guide tubes, diagnostic devices) along a specific path of an accelerator facility. This part is either ...
experiments nowadays compete with spallation sources.


Technical aspects

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 Enriched uranium is a type of uranium in which the percent composition of uranium-235 (written 235U) has been increased through the process of isotope separation. Naturally occurring uranium is composed of three major isotopes: uranium-238 (238U ...
, typically up to 20%
U-235 Uranium-235 (235U or U-235) is an isotope of uranium making up about 0.72% of natural uranium. Unlike the predominant isotope uranium-238, it is fissile, i.e., it can sustain a nuclear chain reaction. It is the only fissile isotope that exist ...
, 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 Weapons-grade nuclear material is any fissionable nuclear material that is pure enough to make a nuclear weapon or has properties that make it particularly suitable for nuclear weapons use. Plutonium and uranium in grades normally used in nucle ...
". 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 Convection is single or multiphase fluid flow that occurs spontaneously due to the combined effects of material property heterogeneity and body forces on a fluid, most commonly density and gravity (see buoyancy). When the cause of the convec ...
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

The
International Atomic Energy Agency The International Atomic Energy Agency (IAEA) is an intergovernmental organization that seeks to promote the peaceful use of nuclear energy and to inhibit its use for any military purpose, including nuclear weapons. It was established in 1957 ...
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 Enriched uranium is a type of uranium in which the percent composition of uranium-235 (written 235U) has been increased through the process of isotope separation. Naturally occurring uranium is composed of three major isotopes: uranium-238 (238 ...
(LEU), in support of its nonproliferation policy. By that time, the U.S. had supplied research reactors and highly enriched uranium to 41 countries as part of its
Atoms for Peace "Atoms for Peace" was the title of a speech delivered by U.S. President Dwight D. Eisenhower to the UN General Assembly in New York City on December 8, 1953. The United States then launched an "Atoms for Peace" program that supplied equipment ...
program. In 2004, the U.S. Department of Energy extended its Foreign Research Reactor
Spent Nuclear Fuel Spent nuclear fuel, occasionally called used nuclear fuel, is nuclear fuel that has been irradiated in a nuclear reactor (usually at a nuclear power plant). It is no longer useful in sustaining a nuclear reaction in an ordinary thermal reactor and ...
Acceptance program until 2019. 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 The neutron flux, φ, is a scalar quantity used in nuclear physics and nuclear reactor physics. It is the total length travelled by all free neutrons per unit time and volume. Equivalently, it can be defined as the number of neutrons travellin ...
research reactors, that does not fail through swelling, has been slower than expected. , 72 HEU research reactors remain.


Designers and constructors

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 The Australian Nuclear Science and Technology Organisation (ANSTO) is a statutory body of the Australian government, formed in 1987 to replace the Australian Atomic Energy Commission. Its head office and main facilities are in southern outs ...
for the design, construction and commissioning of the
Open-pool Australian lightwater reactor The Open-pool Australian lightwater reactor (OPAL) is a 20 megawatt (MW) swimming pool nuclear research reactor. Officially opened in April 2007, it replaced the High Flux Australian Reactor as Australia's only nuclear reactor, and is loca ...
(OPAL). Four companies were prequalified:
Atomic Energy of Canada Limited Atomic Energy of Canada Limited (AECL) is a Canadian federal Crown corporation and Canada's largest nuclear science and technology laboratory. AECL developed the CANDU reactor technology starting in the 1950s, and in October 2011 licensed thi ...
(AECL),
INVAP INVAP S.E. is an Argentine company that provides design, integration, construction and delivery of equipment, plants and devices. The company operates in North America, Europe, Asia Pacific, Latin America, the Middle East and Africa, and delivers ...
,
Siemens Siemens AG ( ) is a German multinational conglomerate corporation and the largest industrial manufacturing company in Europe headquartered in Munich with branch offices abroad. The principal divisions of the corporation are ''Industry'', '' ...
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

*
Aqueous homogeneous reactor Aqueous homogeneous reactors (AHR) are a type of nuclear reactor in which soluble nuclear salts (usually uranium sulfate or uranium nitrate) are dissolved in water. The fuel is mixed with the coolant and the moderator, thus the name "homogeneo ...
*
Argonaut class reactor The Argonaut class reactor is a design of small nuclear research reactor. Many have been built throughout the world, over a wide range of power levels. Its functions are to teach nuclear reactor theory, nuclear physics Nuclear physics is the fie ...
*
DIDO Dido ( ; , ), also known as Elissa ( , ), was the legendary founder and first queen of the Phoenician city-state of Carthage (located in modern Tunisia), in 814 BC. In most accounts, she was the queen of the Phoenician city-state of Tyre (t ...
class, six high-flux reactors worldwide *
TRIGA TRIGA (Training, Research, Isotopes, General Atomics) is a class of nuclear research reactor designed and manufactured by General Atomics. The design team for TRIGA, which included Edward Teller, was led by the physicist Freeman Dyson. Design ...
, a highly successful class with >50 installations worldwide *
SLOWPOKE reactor Slowpoke or Slow Poke may refer to: * "Slow Poke", a 1951 American country music hit song * "Slowpoke", a song by Crosby, Stills, Nash & Young * ''Slowpoke'' (comic strip), weekly comic strip by Jen Sorensen * Slowpoke (Pokémon), a fictional s ...
class, developed by AECL, Canada *
Miniature neutron source reactor The Chinese built Miniature Neutron Source reactor (MNSR) is a small and compact research reactor modeled on the Canadian HEU SLOWPOKE-2 design. The MNSR is tank-in-pool type, with highly enriched fuel (~ 90% U235 ). The tank is immersed in a lar ...
, based on the SLOWPOKE design, developed by AECL, currently exported by China * Aerojet General Nucleonics, 201 Models. Developed by Aerojet General in the United States. 3 current reactors in operation at Idaho State University, The University of New Mexico, and Texas A&M University.


Research centers

A complete list can be found at the
List of nuclear research reactors A ''list'' is any set of items in a row. List or lists may also refer to: People * List (surname) Organizations * List College, an undergraduate division of the Jewish Theological Seminary of America * SC Germania List, German rugby unio ...
. Research centers that operate a reactor: Decommissioned research reactors:


References


WNA Information Paper # 61: Research ReactorsNuclear Nonproliferation: DOE Needs to Take Action to Further Reduce the Use of Weapons-Usable Uranium in Civilian Research Reactors
GAO Gao , or Gawgaw/Kawkaw, is a city in Mali and the capital of the Gao Region. The city is located on the River Niger, east-southeast of Timbuktu on the left bank at the junction with the Tilemsi valley. For much of its history Gao was an impor ...
, July 2004, GAO-04-807


External links


IAEA searchable list of Nuclear Research Reactors in the worldThe National Organization of Test, Research, and Training Reactors, Inc.NMI3 - EU-FP7 Integrated Infrastructure Initiative for Neutron Scattering and Muon Spectroscopy
{{Authority control Nuclear reactors Nuclear research reactors Neutron Neutron sources