Rudolf Schulten (16 August 1923 – 27 April 1996) was a German physicist who was professor at

RWTH Aachen University RWTH Aachen University (), in German ''Rheinisch-Westfälische Technische Hochschule Aachen'', is a German public research university located in Aachen, North Rhine-Westphalia, Germany. With more than 47,000 students enrolled in 144 study prog ...

and the main developer of the

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 desig ...

design, which was originally invented 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. Daniel ...

. Schulten's concept compacts silicon carbide-coated uranium granules into hard, billiard-ball-like graphite spheres to be used as fuel for a new high temperature, helium-cooled type of

nuclear reactor A nuclear reactor is a device used to initiate and control a Nuclear fission, fission nuclear chain reaction. They are used for Nuclear power, commercial electricity, nuclear marine propulsion, marine propulsion, Weapons-grade plutonium, weapons ...

AVR reactor

The idea took root and in due course a 46 MWth (megawatt thermal) experimental pebble bed reactor (the Arbeitsgemeinschaft Versuchsreaktor, or

AVR reactor The AVR reactor () was a prototype pebble-bed reactor, located immediately adjacent to Jülich Research Centre in West Germany, constructed in 1960, grid connected in 1967 and shut down in 1988. It was a 15 MWe, 46 MWt test reactor used to devel ...

) was built at the Jülich Research Centre in

Jülich Jülich (; in old spellings also known as ''Guelich'' or ''Gülich'', , , Ripuarian: ''Jöllesch'') is a town in the district of Düren, in the federal state of North Rhine-Westphalia, in western Germany. As a border region between the competin ...

West Germany West Germany was the common English name for the Federal Republic of Germany (FRG) from its formation on 23 May 1949 until German reunification, its reunification with East Germany on 3 October 1990. It is sometimes known as the Bonn Republi ...

. It operated for 21 years but was shut down in the wake of

Chernobyl Chernobyl, officially called Chornobyl, is a partially abandoned city in Vyshhorod Raion, Kyiv Oblast, Ukraine. It is located within the Chernobyl Exclusion Zone, to the north of Kyiv and to the southwest of Gomel in neighbouring Belarus. ...

, and multiple safety issues.

HTR-MODUL project

Some of the last pebble fuel tested in the AVR was for a low enriched uranium (LEU) fuel cycle anticipated for use in the HTR-MODUL project design by Interatom/

SIEMENS Siemens AG ( ) is a German multinational technology conglomerate. It is focused on industrial automation, building automation, rail transport and health technology. Siemens is the largest engineering company in Europe, and holds the positi ...

South African Pebble Bed Modular Reactor

Based on the AVR, South Africa along with international partners developed an updated version called the PBMR. The

TRISO Nuclear fuel refers to any substance, typically fissile material, which is used by nuclear power stations or other nuclear devices to generate energy. Oxide fuel For fission reactors, the fuel (typically based on uranium) is usually based o ...

fuel elements could use either Thorium or U-235 in the form of LEU as fuel. The project was cancelled in 2010 due to lack of investment, even though the technology has essentially been completely developed.

HTR-10 China, HTR-PM

The technology is currently being developed mainly in

China China, officially the People's Republic of China (PRC), is a country in East Asia. With population of China, a population exceeding 1.4 billion, it is the list of countries by population (United Nations), second-most populous country after ...

who currently operate a 10 MW test reactor ( HTR-10) of this type. The Chinese are, as of 2015, building a commercial pebble-bed reactor: HTR-PM, with two 100MWe reactors.''China's HTR-PM reactor achieves first criticality'' Sept 2021
/ref> One achieved a sustained chain reaction (criticality) in Sept 2021.

References

* Kirchner, Ulrich: ''Der Hochtemperaturreaktor - Konflikte, Interessen, Entscheidungen'', Campus Verlag, Frankfurt/New York, Campus Forschung Vol. 667, 1991. Werner von Siemens Ring laureates Academic staff of RWTH Aachen University Commanders Crosses of the Order of Merit of the Federal Republic of Germany 1920 births 1996 deaths Academic staff of the Karlsruhe Institute of Technology {{physicist-stub