DIDO was a materials testing

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 ...

at the Atomic Energy Research Establishment at

Harwell, Oxfordshire Harwell is a village and civil parish in the Vale of White Horse about west of Didcot, east of Wantage and south of Oxford. The parish measures about north – south, and almost east – west at its widest point. In 1923 its area was . Hi ...

in the

United Kingdom The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom (UK) or Britain, is a country in Europe, off the north-western coast of the European mainland, continental mainland. It comprises England, Scotlan ...

. It used

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 ...

metal fuel, and heavy water as both neutron moderator and primary coolant. There was also a

graphite Graphite () is a crystalline form of the element carbon. It consists of stacked layers of graphene. Graphite occurs naturally and is the most stable form of carbon under standard conditions. Synthetic and natural graphite are consumed on lar ...

neutron reflector A neutron reflector is any material that reflects neutrons. This refers to elastic scattering rather than to a specular reflection. The material may be graphite, beryllium, steel, tungsten carbide, gold, or other materials. A neutron reflector ...

surrounding the core. In the design phase, DIDO was known as AE334 after its engineering design number. DIDO was designed to have a 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 ...

, largely to reduce the time required for testing of materials intended for use in nuclear power reactors. This also allowed for the production of intense beams of neutrons for use in

neutron diffraction Neutron diffraction or elastic neutron scattering is the application of neutron scattering to the determination of the atomic and/or magnetic structure of a material. A sample to be examined is placed in a beam of thermal or cold neutrons to o ...

. DIDO was shut down in 1990. The primary facilities decommissioning is expected to be complete in 2023 with the reactor decommissioning completed in 2031 and final site clearance achieved in 2064 In all, six DIDO class reactors were constructed based on this design: *DIDO, first criticality 1956. *

PLUTO Pluto (minor-planet designation: 134340 Pluto) is a dwarf planet in the Kuiper belt, a ring of bodies beyond the orbit of Neptune. It is the ninth-largest and tenth-most-massive known object to directly orbit the Sun. It is the largest ...

, also at Harwell, first criticality 1957. *

HIFAR The High Flux Australian Reactor (HIFAR) was Australia's first nuclear reactor. It was built at the Australian Atomic Energy Commission (later ANSTO) Research Establishment at , Sydney. The reactor was in operation between 1958 and 2007, when i ...

( Australia), first criticality January 1958. * Dounreay Materials Testing Reactor (DMTR) at

Dounreay Nuclear Power Development Establishment Dounreay (; gd, Dùnrath) is a small settlement and the site of two large nuclear establishments on the north coast of Caithness in the Highland area of Scotland. It is on the A836 road west of Thurso. The nuclear establishments were creat ...

in Scotland, first criticality May 1958. *DR-3 at Risø National Laboratory (

Denmark ) , song = ( en, "King Christian stood by the lofty mast") , song_type = National and royal anthem , image_map = EU-Denmark.svg , map_caption = , subdivision_type = Sovereign state , subdivision_name = Kingdom of Denmark , establish ...

), first criticality January 1960.http://sundhedsstyrelsen.dk/da/sundhed/straalebeskyttelse/nukleare-anlaegatomanlaeg/udgivelser/~/media/41E3012B782547DE9711945FB39E5E52.ashx p.15, retrieved 19 February 2014 * FRJ-II at

Jülich Research Centre Jülich (; in old spellings also known as ''Guelich'' or ''Gülich'', nl, Gulik, french: Juliers, Ripuarian: ''Jöllesch'') is a town in the district of Düren, in the federal state of North Rhine-Westphalia, Germany. As a border region betwe ...

(

Germany Germany,, officially the Federal Republic of Germany, is a country in Central Europe. It is the second most populous country in Europe after Russia, and the most populous member state of the European Union. Germany is situated betwe ...

), first criticality 1962. HIFAR was the last to shut down, in 2007.

References

Buildings and structures in Oxfordshire Former nuclear research institutes Neutron facilities Nuclear research institutes in the United Kingdom Nuclear research reactors Science and technology in the United Kingdom Vale of White Horse {{Oxfordshire-struct-stub

See also

References