DIDO-class reactor and it was used for neutron scattering experiments. It was operated by the Central Research Reactors Division (ZFR). FRJ-2 was the strongest neutron source in Germany until the research neutron source Heinz Maier-Leibnitz in Garching (FRM II) was put in operation. FRJ-2 was primarily used to conduct scattering and spectroscopic experiments on condensed matter. It was in operation from 14 November 1962 until 2 May 2006. In 2006, the Jülich Centre for Neutron Science (JCNS) was founded, reflecting Forschungszentrum Jülich’s role as a national competence centre for neutron scattering. Six of the most important instruments were moved from FRJ-2 to FRM II; new instruments were also assembled there. AVR In 1956, an interest group was formed to prepare the construction of the AVR reactor. In 1959, it became the “Arbeitsgemeinschaft Versuchsreaktor GmbH” (AVR GmbH) – a consortium of 15 local electricity suppliers headed by the Düsseldorf municipal utilities (Stadtwerke Düsseldorf) as the owner and operator (other partners included the municipal utilities in Aachen, Bonn, Bremen, Hagen, Hanover, Munich, and Wuppertal). The aim was to demonstrate the feasibility and operability of a graphite-moderated, gas-cooled high-temperature reactor to produce electricity. BBC and Krupp were responsible for construction of the AVR reactor, which began in August 1961 and was completed in 1966, after the consortium had received the design contract in April 1957 and the construction contract in February 1959. The cost of construction was in the region of DM 100 million. In 1967, the AVR reactor was put into operation and began feeding electricity into the national power grid. On 31 December 1988, the AVR reactor was shut down; during its operation, it had proven the feasibility of the pebble bed reactor. Karl Strauss said in 2016 that “the facility had generally been operated without any problems”. The mean availability was 60.4%. AVR received scientific support and operating subsidies from the Nuclear Research Centre Jülich (KFA) but was formally independent. From the mid-1980s, the then KFA reduced its commitment to the further development of the gas-cooled high-temperature reactor. The AVR pebble bed reactor is still being dismantled today (see its dismantling and disposal). The severe contamination of the reactor core with radioactive graphite dust particles proved particularly difficult. This contamination was caused by the coating of the fuel pellets made of silicon carbide and porous carbon, which leaked under the high temperatures in the reactor core and released radioactive fission