Dounreay (; gd, Dùnrath) is a small settlement and the site of two large nuclear establishments on the north

coast The coast, also known as the coastline or seashore, is defined as the area where land meets the ocean, or as a line that forms the boundary between the land and the coastline. The Earth has around of coastline. Coasts are important zones in ...

of Caithness in the

Highland Highlands or uplands are areas of high elevation such as a mountainous region, elevated mountainous plateau or high hills. Generally speaking, upland (or uplands) refers to ranges of hills, typically from up to while highland (or highlands) is ...

area of Scotland. It is on the A836 road west of

Thurso Thurso (pronounced ; sco, Thursa, gd, Inbhir Theòrsa ) is a town and former burgh on the north coast of the Highland council area of Scotland. Situated in the historical County of Caithness, it is the northernmost town on the island of Gre ...

. The nuclear establishments were created in the 1950s. They were the Nuclear Power Development Establishment (NPDE) for the development of civil

fast breeder reactor A breeder reactor is a nuclear reactor that generates more fissile material than it consumes. Breeder reactors achieve this because their neutron economy is high enough to create more fissile fuel than they use, by irradiation of a fertile mater ...

s, and the Vulcan Naval Reactor Test Establishment (NRTE), a military submarine reactor testing facility. Both these no longer perform their original research functions and will be completely decommissioned, some of which has been in progress for a while. The two establishments have been a major element in the economy of Thurso and Caithness, but this will decrease with the progress of decommissioning. The NPDE will enter an interim care and surveillance state by 2036, and become a brownfield site by 2336. An announcement in July 2020 that the Nuclear Decommissioning Authority (NDA) will be taking over direct management of the site from the site licence company Dounreay Site Restoration Limited (DSRL) in 2021 has alleviated fears of 560 job losses. The NRTE is to be decommissioned under a ten-year contract starting in 2023, ending in the creation of a brownfield site, which would be transferred to the NDA.The Press and Journal, 13 March 2020
/ref>

Dounreay settlement

Dounreay is the site of Dounreay Castle (now a ruin)Coventry, Martin (1997) ''The Castles of Scotland''. Goblinshead. p.147 and its name derives from the Gaelic for 'fort on a mound'. Dounreay was the site of the battle of

Sandside Chase The Sandside Chase (The Chase of Sandside, The Chase of Sansett; in Gaelic, Ruoig-Hansett, Ruaig Handside or Ruaig-Shansaid) was a Scottish clan battle which took place in 1437 in Caithness, about west of Thurso. The Clan Mackay launched a raid ...

in 1437. Robert Gordon's map of Caithness, 1642, uses ''Dounrae'' as the name of the castle. William J. Watson's ''The Celtic Place-names of Scotland'' gives the origin as ''Dúnrath'', possibly a reference to a broch. Dounreay was the site of a

World War II World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposing ...

airfield An aerodrome ( Commonwealth English) or airdrome (American English) is a location from which aircraft flight operations take place, regardless of whether they involve air cargo, passengers, or neither, and regardless of whether it is for pub ...

, called

RAF Dounreay RAF Dounreay was built for RAF Coastal Command in 1944, but not used by them. It was transferred to the Royal Navy as HMS Tern II, but not commissioned and on care and maintenance until 1954. In 1955 the airfield was taken over by the United Ki ...

. It became HMS ''Tern'' (II) in 1944 when the airfield was transferred to the

Admiralty Admiralty most often refers to: *Admiralty, Hong Kong *Admiralty (United Kingdom), military department in command of the Royal Navy from 1707 to 1964 *The rank of admiral *Admiralty law Admiralty can also refer to: Buildings * Admiralty, Traf ...

from

RAF Coastal Command RAF Coastal Command was a formation within the Royal Air Force (RAF). It was founded in 1936, when the RAF was restructured into Fighter, Bomber and Coastal Commands and played an important role during the Second World War. Maritime Aviation ...

as a satellite of HMS ''Tern'' at Twatt in Orkney. It never saw any action during the war and was placed into ''care and maintenance'' in 1949.

Nuclear sites

There are two nuclear sites at Lower Dounreay built on and around the site of the former airfield. The Nuclear Power Development Establishment site is owned by the Nuclear Decommissioning Authority (NDA) but was previously owned and run by the

United Kingdom Atomic Energy Authority The United Kingdom Atomic Energy Authority is a UK government research organisation responsible for the development of fusion energy. It is an executive non-departmental public body of the Department for Business, Energy and Industrial Strategy ...

. Adjacent to this site is the Ministry of Defence Vulcan Naval Reactor Test Establishment. The two sites are best known for their five

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, three formerly owned and operated by the UKAEA and two by the Ministry of Defence. During the 1980s and 1990s, a visitor centre was opened in the former air traffic control tower. Visitors would be taken by bus to the PFR building where anything electronic, including watches and cameras, would be stored away securely until return. White coats were worn along with radiation badges. A guided tour through the air lock into the reactor building was then conducted, walking around the reactor core and then returning via scientists working behind thick mineral glass screens.

Dounreay Nuclear Power Development Establishment

Dounreay Nuclear Power Development Establishment was formed in 1955 primarily to pursue the UK Government policy of developing civil

(FBR) technology. The site was operated by the

(UKAEA). Three

s were built there by the UKAEA, first a materials test reactor, then two fast breeder reactor prototypes. There were also fabrication and reprocessing facilities for the materials test rigs and for fuel for the FBRs. Dounreay was chosen as the reactor location, remote from large centres of population, for safety reasons. The site has been managed by the site licence Dounreay Site Restoration Ltd (DSRL) since 2012, but the NDA will assume complete control when DSRL becomes a wholly owned subsidiary of the NDA in March 2021.

Dounreay Materials Test Reactor

The first of the Dounreay reactors to achieve criticality was the Dounreay Materials Test Reactor (DMTR) in May 1958, which was a

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 research reactor, producing a high neutron flux. This reactor was used to test the performance of materials under intense neutron irradiation, particularly those intended for fuel cladding and other structural uses in a

fast neutron reactor A fast-neutron reactor (FNR) or fast-spectrum reactor or simply a fast reactor is a category of nuclear reactor in which the fission chain reaction is sustained by fast neutrons (carrying energies above 1 MeV or greater, on average), as opposed ...

core. Test pieces were encased in uranium-bearing alloy to increase the already high neutron flux of this class of reactor, and then chemically stripped of this coating after irradiation. DMTR was closed in 1969 when materials testing work was consolidated at Harwell Laboratory. DFR Schematic

Dounreay Fast Reactor

The second operational reactor (although the first to commence construction) was the Dounreay Fast Reactor (DFR), which achieved criticality on 14 November 1959. Power was exported to the National Grid from 14 October 1962 until the reactor was taken offline for decommissioning in March 1977. During its operational lifespan, DFR produced over 600million kWh of electricity., archive-url = DFR and associated facilities cost £15million to build in late 1950s money (equivalent to £370million in 2021). It was designed to generate 60MW thermal power and achieve a 2% fuel burn up. It reached 30MWt in August 1962, and 60MWt in July 1963 allowing it to produce its rated 14MWe (electrical). The reactor was surrounded by a steel sphere, still a prominent feature of the landscape, which was constructed by the Motherwell Bridge Company. DFR was a loop-type FBR cooled by primary and secondary NaK circuits, with 24 primary coolant loops. The reactor core was initially fuelled with uranium metal fuel stabilised with molybdenum and clad in niobium. The core was later used to test oxide fuels for PFR and provide experimental space to support overseas fast reactor fuel and materials development programmes. It had over 5,000 breeder elements of natural uranium in stainless steel arranged in an inner and outer breeder sections. Many were replaced in 1965.

Prototype Fast Reactor (PFR)

The third and final UKAEA-operated reactor to be built on the Dounreay site was the Prototype Fast Reactor (PFR). In 1966, it was announced that the PFR would be built at Dounreay. PFR was a pool-type

, cooled by 1,500tonnes of liquid

sodium Sodium is a chemical element with the symbol Na (from Latin ''natrium'') and atomic number 11. It is a soft, silvery-white, highly reactive metal. Sodium is an alkali metal, being in group 1 of the periodic table. Its only stable ...

and fueled with

MOX Mixed oxide fuel, commonly referred to as MOX fuel, is nuclear fuel that contains more than one oxide of fissile material, usually consisting of plutonium blended with natural uranium, reprocessed uranium, or depleted uranium. MOX fuel is an al ...

. The design output of PFR was 250MWe (electrical). It achieved criticality in 1974 and began supplying National Grid power in January 1975. There were many delays and reliability problems before reaching full power. It had three cooling circuits. Leaks in the sodium water steam generators shutdown one and then two of the cooling circuits in 1974 and 1975. By August 1976 it had reached 500MWt, (to produce about 166 MWe) and in 1985 it first reached its design output of 250MWe. In 1988, it was announced that funding for FBR research was being cut from £105million to £10million per year, and the PFR funding would end in 1994. The reactor was taken offline in 1994, marking the end of nuclear power generation at the site. It had supplied 9,250GWh in all. The lifetime load factor recorded by the

IAEA 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 195 ...

was 26.9%. The control panel for the reactor was earmarked for an exhibition on the reactor at the London

Science Museum A science museum is a museum devoted primarily to science. Older science museums tended to concentrate on static displays of objects related to natural history, paleontology, geology, industry and industrial machinery, etc. Modern trends in ...

in 2016.

Subsequent activity

Since the reactors have all been shut down, care and maintenance of old plant and decommissioning activities have meant that Dounreay has still retained a large workforce. Commercial reprocessing of

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 ...

and

waste Waste (or wastes) are unwanted or unusable materials. Waste is any substance discarded after primary use, or is worthless, defective and of no use. A by-product, by contrast is a joint product of relatively minor economic value. A waste prod ...

on the Dounreay site was stopped by the UK government in 1998 although some waste is still accepted from other nuclear facilities in special circumstances.

Significant accidents

Sodium explosion

A deep shaft at the plant was packed with

radioactive waste Radioactive waste is a type of hazardous waste that contains radioactive material. Radioactive waste is a result of many activities, including nuclear medicine, nuclear research, nuclear power generation, rare-earth mining, and nuclear weapons r ...

and at least 2kg of sodium and potassium. On 10 May 1977, seawater, which flooded the shaft, reacted violently with the sodium and potassium, throwing off the massive steel and concrete lids of the shaft. This explosion littered the area with radioactive particles.

Radioactive fuel swarf

Tens of thousands of fragments of radioactive fuel escaped the plant between 1963 and 1984, resulting in fishing being banned within of the plant since 1997. These milled shards are thought to have washed into the sea as cooling ponds were drained. , over 2,300 radioactive particles had been recovered from the sea floor, and over 480 from the beaches. the 2km ban on harvesting seafood was still in place, but there were no other restrictions.

Major power failure

Following an incident in May 1998, where a mechanical digger cut through a main power cable and interrupted the site's main and back-up electricity supplies for 16 hours, operations were halted in the Fuel Cycle Area (FCA) and a safety audit of the plant was undertaken by the UK Health and Safety Executive and the

Scottish Environment Protection Agency The Scottish Environment Protection Agency (SEPA; gd, Buidheann Dìon Àrainneachd na h-Alba) is Scotland's environmental regulator and national flood forecasting, flood warning and strategic flood risk management authority.Friends of the Earth Scotland, but the environmental group remained opposed to further fuel reprocessing at the site.

Removal of fuel

Following the 1998 report, the Department of Trade and Industry was presented with three options for dealing with 25tonnes of radioactive reactor fuel at Dounreay. The options were: #to reprocess it at Dounreay, #to reprocess some at Dounreay and some at Sellafield, or #to store it above ground at Dounreay. A plan was eventually devised to remove irradiated and unirradiated fuel to the Sellafield nuclear site, starting in 2014. In 2018, the NDA reported that it would be completed in 2018/2019.

Nuclear Decommissioning Authority ownership

On 1 April 2005, the Nuclear Decommissioning Authority (NDA) became the owner of the site, with the UKAEA remaining as operator. Decommissioning of Dounreay was initially planned to bring the site to an interim care and surveillance state by 2036, and as a brownfield site by 2336, at a total cost of £2.9billion. A new company called Dounreay Site Restoration Limited (DSRL) was formed as a subsidiary of the United Kingdom Atomic Energy Authority (UKAEA) to handle the decommissioning process. By May 2008, decommissioning cost estimates had been revised. Removal of all waste from the site was expected to take until the late 2070s to complete and the end-point of the project was scheduled for 2300. Apart from decommissioning the reactors, reprocessing plant, and associated facilities, there were five main environmental issues to be dealt with: * A shaft used for intermediate level

nuclear waste Radioactive waste is a type of hazardous waste that contains radioactive material. Radioactive waste is a result of many activities, including nuclear medicine, nuclear research, nuclear power generation, rare-earth mining, and nuclear weapons ...

disposal was contaminating groundwater, and would be threatened by coastal erosion in about 300years. The shaft was never designed as a waste depository, but was used as such on a very ad hoc and poorly monitored basis, without reliable waste disposal records being kept. It was originally used to construct a tunnel for the sea discharge pipe. Later use of the shaft as a convenient waste depository had resulted in one

hydrogen gas Hydrogen is the chemical element with the symbol H and atomic number 1. Hydrogen is the lightest element. At standard conditions hydrogen is a gas of diatomic molecules having the formula . It is colorless, odorless, tasteless, non-toxic, a ...

explosion caused by

and

potassium Potassium is the chemical element with the symbol K (from Neo-Latin ''kalium'') and atomic number19. Potassium is a silvery-white metal that is soft enough to be cut with a knife with little force. Potassium metal reacts rapidly with atmosph ...

wastes reacting with water. At one time it was normal for workers to fire rifles into the shaft to sink polythene bags floating on water. * Irradiated nuclear fuel particles on the seabed near the plant, estimated to be about several hundreds of thousands in number, caused by old fuel rod fragments being pumped into the sea. The beach had been closed since 1983 due to this. In 2008, a clean-up project using Geiger counter-fitted robot submarines was planned to search out and retrieve each particle individually. Particles were still being washed ashore at Sandside Bay beach and one particle at a popular tourist beach at Dunnet in 2006. In 2012, a two million

becquerel The becquerel (; symbol: Bq) is the unit of radioactivity in the International System of Units (SI). One becquerel is defined as the activity of a quantity of radioactive material in which one nucleus decays per second. For applications relatin ...

particle was found at Sandside beach, twice as radioactive as any particle previously found. * of radiologically contaminated land, and of chemically contaminated land. * of high and medium active liquors and of unconditioned intermediate level nuclear waste in store. * of

, of which are radioactively contaminated from the Prototype Fast Reactor. Historically, much of Dounreay's nuclear waste management was poor. On 18 September 2006, Norman Harrison, acting chief operating officer, predicted that more problems will be encountered from old practices at the site as the decommissioning effort continues. Some parts of the plant are being entered for the first time in 50years. In 2007, UKAEA pleaded guilty to four charges under the Radioactive Substances Act 1960 relating to activities between 1963 and 1984, one of disposing of radioactive waste at a landfill site at the plant between 1963 and 1975, and three of illegally dumping radioactive waste and releasing nuclear fuel particles into the sea, resulting in a fine of £140,000. In 2007 a new decommissioning plan was agreed, with a schedule of 25years and a cost of £2.9billion, a year later revised to 17years at a cost of £2.6billion. Due to the uranium and plutonium held at the site, it is considered a security risk and there is a high police presence. In 2013 ,the detail design of the major project to decommission the intermediate level waste shaft was completed, and work was to begin later in the year. The work would include the recovery and packaging of over 1,500tonnes of radioactive waste. , the "interim end state" planned date had been brought forward to 2022–2025. In March 2014, firefighters extinguished a small fire in an area used to store low-level nuclear waste. On 7 October 2014, a fire on the PFR site led to a "release of radioactivity via an unauthorised route". The

Office for Nuclear Regulation The Office for Nuclear Regulation (ONR) is the regulator for the nuclear industry in the United Kingdom.< ...

(ONR) concluded that "procedural non-compliances and behavioural practices" led to the fire, and served an improvement notice on Dounreay Site Restoration Limited. In 2015 decommissioning staff expressed a lack of confidence in management at the plant and fear for their safety. In 2016, the task of dismantling the PFR core commenced. Plans were also announced to move about of waste

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 ...

to the United States. On 7 June 2019, there was a low-level

radioactive contamination Radioactive contamination, also called radiological pollution, is the deposition of, or presence of radioactive substances on surfaces or within solids, liquids, or gases (including the human body), where their presence is unintended or undesirab ...

incident that led to the evacuation of the site. A DSRL spokesman said: "There was no risk to members of the public, no increased risk to the workforce and no release to the environment". On 23 December 2019, the NDA announced completion of the transfer of all plutonium from Dounreay to Sellafield, where all significant UK stocks of plutonium are now held. On 20 August 2020, a new date for the site to become available for other uses was announced of 2333, as part of a new draft strategy for reclamation.

Framework contracts

In April 2019, Dounreay Site Restoration Limited (DSRL) awarded six framework contracts for decommissioning services at Dounreay. The total value of these contracts is estimated to be £400million.

Vulcan Nuclear Reactor Testing Establishment (NRTE)

The Vulcan Naval Reactor Test Establishment (NRTE) (formerly HMS ''Vulcan'') is a Ministry of Defence (MoD) establishment housing the prototype nuclear propulsion plants of the type operated by the

Royal Navy The Royal Navy (RN) is the United Kingdom's naval warfare force. Although warships were used by English and Scottish kings from the early medieval period, the first major maritime engagements were fought in the Hundred Years' War against ...

in its submarine fleet. Originally it was known as the Admiralty Reactor Test Establishment (ARTE). For over 40years Vulcan has been the cornerstone of the Royal Navy's nuclear propulsion programme, testing and proving the operation of five generations of reactor core. Its reactors have significantly led the operational submarine plants in terms of operation hours, proving systems, procedures and safety. The reactors were run at higher levels of intensity than those on submarines with the intention of discovering any system problems before they might be encountered on board submarines.

Rolls-Royce Rolls-Royce (always hyphenated) may refer to: * Rolls-Royce Limited, a British manufacturer of cars and later aero engines, founded in 1906, now defunct Automobiles * Rolls-Royce Motor Cars, the current car manufacturing company incorporated in ...

, which designs and procures all the reactor plants for the Royal Navy from its Derby offices, operates Vulcan on behalf of the MoD and employs around 280 staff there, led by a small team of staff from the Royal Navy. Reactors developed include the PWR1 and PWR2. In 2011, the MoD stated that NRTE could be scaled down or closed after 2015 when the current series of tests ends. Computer modelling and confidence in new reactor designs meant testing would no longer be necessary. The cost of decommissioning NRTE facilities when they become redundant, including

disposal, was estimated at £2.1billion in 2005. Its final reactor shut down on 21 July 2015, with post operational work continuing to 2022. In March 2020, it was reported that tenders were being issued to decontaminate and dismantle the reactor complex under a ten-year contract, ending in the creation of a "brownfield" site, which would be transferred to the Nuclear Decommissioning Authority. This decommissioning programme would start in 2023, following the removal of all fuel to the NDA Sellafield site.

Dounreay Submarine Prototype 1 (DSMP1)

The first reactor, PWR1, is known as Dounreay Submarine Prototype 1 (DSMP1). The reactor plant was recognised by the Royal Navy as one of Her Majesty's Submarines (HMS) and was commissioned as HMS ''Vulcan'' in 1963. It went critical in 1965. HMS ''Vulcan'' is a Rolls-Royce PWR 1 reactor plant and tested Cores A, B and Z before being shut down in 1984. In 1987, the plant was re-commissioned as LAIRD (Loss of Coolant Accident Investigation Rig Dounreay) a non-nuclear test rig, the only one of its kind in the world. LAIRD trials simulated loss of coolant accidents to prove the effectiveness of systems designed to protect the reactor in loss-of-coolant accidents.

Shore Test Facility (STF)

The second reactor, PWR2, is housed in the Shore Test Facility (STF), was commissioned in 1987, and went critical with Core G the same year. The plant was shut down in 1996, and work began to refit the plant with the current core, Core H, in February 1997. This work was completed in 2000 and after two years of safety justification the plant went critical in 2002. Vulcan Trials Operation and Maintenance (VTOM) (the programme under which Core H is tested) was completed and the reactor shut down on 21 July 2015. The reactor will be de-fuelled and examined, and post operational work will continue to 2022. The site would then be decommissioned along with facilities at neighbouring UKAEA Dounreay. In January 2012, radiation was detected in the reactor's coolant water, caused by a microscopic breach in fuel cladding. This discovery led to being scheduled to be refuelled and contingency measures being applied to other ''Vanguard'' and ''Astute''-class submarines, at a cost of £270million, before similar problems might arise on the submarines. This was not revealed to the public until 2014.

References

External links

Dounreay Site Restoration
official website
Dounreay - Future Plans
NDA
Shore Based Testing
Rolls-Royce Marine
Vulcan leads the way for Navy nuclear reactors
Navy News, 7 January 2003
Vulcan takes on additional role
Navy News, 4 February 2003
Dounreay
Scottish Parliament research note, 9 January 2001
Dounreay - Fast Breeder
Caithness.Org
The Dounreay Sphere - Design and Construction
(video - 25min 11sec), UKAEA, Dounreay TV
The Building of the Prototype Fast Reactor
(video - 23min 44sec), UKAEA, Dounreay TV

UKAEA, December 2005

Edmund Nuttall, January 2007
Latest reports on monitoring of beaches near Dounreay. Regularly updated
SEPA, November 2006
Seabed robot seeks Dounreay pollution
Nuclear Engineering International, 3 October 2007 {{authority control Caithness Castles in Highland (council area) Buildings and structures in Highland (council area) Former nuclear power stations in Scotland Former nuclear research institutes Liquid metal fast reactors Nuclear research institutes in the United Kingdom