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The AVR reactor (german: Arbeitsgemeinschaft Versuchsreaktor) was a prototype
pebble-bed reactor The pebble-bed reactor (PBR) is a design for a graphite- moderated, gas-cooled nuclear reactor. It is a type of very-high-temperature reactor (VHTR), one of the six classes of nuclear reactors in the Generation IV initiative. The basic des ...
, located immediately adjacent to
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 ...
in
West Germany West Germany is the colloquial term used to indicate the Federal Republic of Germany (FRG; german: Bundesrepublik Deutschland , BRD) between its formation on 23 May 1949 and the German reunification through the accession of East Germany on 3 O ...
, constructed in 1960, grid connected in 1967 and shut down in 1988. It was a 15MWe, 46 MWt test reactor used to develop and test a variety of fuels and machinery. The AVR was based on the concept of a "Daniels pile" by
Farrington Daniels Farrington Daniels (March 8, 1889 – June 23, 1972) was an American physical chemist who is considered one of the pioneers of the modern direct use of solar energy. Biography Daniels was born in Minneapolis, Minnesota on March 8, 1889. Dani ...
, the inventor of pebble bed reactors.
Rudolf Schulten Rudolf Schulten (16 August 1923 – 27 April 1996)—professor at RWTH Aachen University—was the main developer of the pebble bed reactor design, which was originally invented by Farrington Daniels. Schulten's concept compacts silicon carbide-c ...
is commonly recognized as the intellectual father of the reactor. A consortium of 15 community electric companies owned and operated the plant. Over its lifetime the reactor had many accidents, earning it the name "shipwreck." From 2011 to 2014, outside experts examined the historical operations and operational hazards and described serious concealed problems and wrongdoings in their final 2014 report. For example, in 1978 operators bypassed reactor shutdown controls to delay an emergency shutdown during an accident for six days. In 2014 the JRC and AVR publicly admitted to failures. Its decommissioning has been exceptionally difficult, time-consuming and expensive. Since the original operators were overwhelmed by the effort, government agencies took over dismantling and disposal. In 2003 the reactor and its nuclear waste became government property. The temporary storage of 152 casks of spent fuel has been a controversy since 2009. The approval expired in 2013, because stress tests could not sufficiently demonstrate safety; no permanent solution has been reached. Since 2012 plans to export the casks to the United States have been considered due to the extremely high disposal expenses. In 2014, a massive concrete wall to protect against terrorist plane crashes was to be built. On July 2, 2014, the Federal Environment ministry issued an evacuation order for the temporary storage. AVR was the basis of the technology licensed to China to build
HTR-10 HTR-10 is a 10 MWt prototype pebble bed reactor at Tsinghua University in China. Construction began in 1995, achieving its first criticality in December 2000, and was operated in full power condition in January 2003. Two HTR-PM reactors, scale ...
and the
HTR-PM The HTR-PM (球床模块式高温气冷堆核电站) is a small modular nuclear reactor in China. It is the world’s first prototype of a high-temperature gas-cooled (HTGR) pebble-bed generation IV reactor. The reactor unit has a thermal capac ...
, which became operational in 2021.


History

In 1959, 15 municipal electric companies established the 'Association of Experimental Reactor GmbH' (AVR Ltd) to demonstrate the feasibility and viability of a gas-cooled, graphite-moderated high temperature reactor. In 1961,
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and
Krupp The Krupp family (see pronunciation), a prominent 400-year-old German dynasty from Essen, is notable for its production of steel, artillery, ammunition and other armaments. The family business, known as Friedrich Krupp AG (Friedrich Krup ...
began AVR construction, led by
Rudolf Schulten Rudolf Schulten (16 August 1923 – 27 April 1996)—professor at RWTH Aachen University—was the main developer of the pebble bed reactor design, which was originally invented by Farrington Daniels. Schulten's concept compacts silicon carbide-c ...
, performed on almost purely industrial basis until 1964. The federal government provided financial assistance, supported by the politician and founder of the Juelich Research Center (JRC), Leo Brandt. In 1964, Schulten became Director of the JRC and started to devote more attention to the pebble bed reactor. In 1966, AVR first achieved criticality, and was connected to the national power grid in 1967. Construction cost figures vary between 85 and 125 million
Deutsche mark The Deutsche Mark (; English: ''German mark''), abbreviated "DM" or "D-Mark" (), was the official currency of West Germany from 1948 until 1990 and later the unified Germany from 1990 until the adoption of the euro in 2002. In English, it was ...
s ($2.5–3.7bn in 2014). Since about 1970 the AVR GmbH was de facto dependent on JRC, although it remained formally independent until 2003. JRC provided generous operating grants to the AVR GmbH to ensure continued operation, since electricity generation only covered a small part of the
operating costs Operating costs or operational costs, are the expenses which are related to the operation of a business, or to the operation of a device, component, piece of equipment or facility. They are the cost of resources used by an organization just to main ...
. In the mid-1970s annual revenue was about 3 million DM, versus operating and fuel disposal costs of 11 million DM. JRC also subsidized AVR through procurement and disposal of fuel as JRC has been owner of AVR fuel. In addition, the AVR operation was scientifically supervised by JRC.


Fuels tested

From 1974 to 1978, mainly carbide BISO fuel was in the core. From 1983 to 1988, oxide fuel with
TRISO Nuclear fuel is material used in nuclear power stations to produce heat to power turbines. Heat is created when nuclear fuel undergoes nuclear fission. Most nuclear fuels contain heavy fissile actinide elements that are capable of undergoing ...
particles was used.


Higher temperatures

During its initial years (1967-1973) the AVR was nominally operated with cooling gas outlet temperatures of . In February 1974, the cooling gas outlet temperature was raised to 950 °C. These final high temperatures were a
world record A world record is usually the best global and most important performance that is ever recorded and officially verified in a specific skill, sport, or other kind of activity. The book ''Guinness World Records'' and other world records organization ...
for nuclear facilities, though later exceeded by the US test reactor
UHTREX The Ultra-High Temperature Reactor Experiment (UHTREX) was an experimental gas-cooled nuclear reactor run at Los Alamos National Laboratory between 1959 and 1971
. Such high temperatures were supposed to demonstrate the suitability of the AVR for
coal gasification Coal gasification is the process of producing syngas—a mixture consisting primarily of carbon monoxide (CO), hydrogen (H2), carbon dioxide (CO2), methane (CH4), and water vapour (H2O)—from coal and water, air and/or oxygen. Historically, coal ...
, and thus contribute to long-term plans for coal in
Northrhine-Westfalia North Rhine-Westphalia (german: Nordrhein-Westfalen, ; li, Noordrien-Wesfale ; nds, Noordrhien-Westfalen; ksh, Noodrhing-Wäßßfaale), commonly shortened to NRW (), is a state (''Land'') in Western Germany. With more than 18 million inha ...
. Because a pebble bed core cannot be equipped with instruments, the high AVR core temperatures were unknown until one year before the AVR shut-down, in 1988.Moormann, Raine
A safety re-evaluation of the AVR pebble bed reactor operation and its consequences for future HTR concepts
Berichte des Forschungszentrums Jülich 4275, , 51pp, 2008 (In English with 8 pp abstract also in German) In 2000, AVR admitted that it was contaminated with , being the most heavily contaminated nuclear facility worldwide.


Design

The core held about 100,000 fuel element pebbles. Each contained about 1g of U-235. On average each would take 6 to 8 months to pass through the core. Helium flowed up through the core of pebbles.


Contamination, internal and external

AVR's helium outlet temperature was 950 °C, but fuel temperature instabilities occurred during operation with localised exceedingly high temperatures. As a consequence the whole reactor vessel became heavily contaminated by Cs-137 and Sr-90. Concerning beta-contamination AVR is the highest contaminated nuclear installation worldwide as AVR management confirmed 2001. Thus in 2008, the reactor vessel was filled with light concrete to fixate the radioactive fine particule dust. In 2012, the reactor vessel of 2100 metric tons was to be transported about 200 meters by air-cushion sled and seven cranes to an intermediate storage site. During a severe water accident in 1978, Sr-90 leaked, and in 1999 soil and groundwater contamination below the reactor was discovered, as confirmed by the German government in February 2010.R. Moorman
Decommissioning problems of German pebble bed reactors
14 pages, NURIS-1, Vienna, 16/17 April 2015


Decommissioning

Fuel removal out of AVR was difficult and lasted four years. During this time it became obvious that the AVR bottom reflector was broken; about 200 fuel pebbles remain wedged in its crack. Currently no dismantling method for the AVR vessel exists. It is planned to develop some procedure during the next 60 years and to start with vessel dismantling at the end of the 21st century. After the AVR vessel is moved into intermediate storage, the reactor buildings will be dismantled, and soil and groundwater will be decontaminated. Costs from 1988 to present are €700 million. The total AVR decommissioning costs are expected to be in the order of €1.5 to 2.5 billion, all public funds, i.e. to exceed its construction costs by far.


Independent expert review report, 2014

From 2011 to 2014, outside experts examined the historical operations and operational hazards and in April 2014, published a report on the AVR operation. The report listed hidden or downplayed events and accidents and described serious concealed problems and wrongdoings. For example, in 1978 operators bypassed reactor shutdown controls to delay an emergency shutdown during an accident for six days. In 2014 the JRC and AVR publicly admitted to failures and issued a regret about its failures and scientific misconduct with respect to the AVR.Forschungszentrum Jülic

Last update: 8.1.2016


See also

*
Skyshine (Radiation) skyshine describes the ionizing radiation emitted by a nuclear technical or medical facility, reaching the facility's surroundings not directly, but indirectly through reflection and scattering at the atmosphere back to earth's ...
*
Thorium High Temperature Reactor The THTR-300 was a thorium cycle high-temperature nuclear reactor rated at 300 MW electric (THTR-300) in Hamm-Uentrop, Germany. It started operating in 1983, synchronized with the grid in 1985, operated at full power in February 1987 and was shut ...


References


External links


Jülich Research Centre

The Pebble Bed Evolution
June 2005 (
PDF Portable Document Format (PDF), standardized as ISO 32000, is a file format developed by Adobe in 1992 to present documents, including text formatting and images, in a manner independent of application software, hardware, and operating systems. ...
, 17KB). * Moormann, Raine
A safety re-evaluation of the AVR pebble bed reactor operation and its consequences for future HTR concepts
Berichte des Forschungszentrums Jülich 4275, , 51pp, 2008 (In English with 8 pp abstract also in German) {{DEFAULTSORT:Avr Reactor Pebble bed reactors Former nuclear power stations in Germany Radioactively contaminated areas