HTGR Knowledge Base

Conference Article: Operational experience with HTR-fuel in the AVR experimental power station

Ivens, G.; Wimmers, M. (Arbeitsgemeinschaft Versuchsreaktor (AVR) GmbH, Juelich (Germany))

Abstract

The 15 MW experimental power station with HTR reactor, operated by Arbeitsgemeinschaft Versuchsreaktor (AVR) in Juelich, FRG, went into operation in 1967. One of its main tasks is to test different kinds of fuel elements and to demonstrate in how far the concept of the pebble-bed reactor permits a safe and reliable operation at high gas temperatures. Evaluation can be summarized as follows: Pressed fuel elements with highly enriched (UTh)C2 with Biso coating show up a good retention capability for fission products up to hot-gas temperatures of 900 deg. C. No particle damages arise up to highest burnups. At higher temperatures mainly strontium is released which not only impedes repair works on the primary system, but also lowers corrosion resistance of fuel element graphite. Pressed fuel elements with highly enriched (ThU)O2 and Biso coating shop up an excellent behaviour without particle damage, even at hog-gas temperatures of 950 deg. C. In particular all 15,000 fuel elements introduced since 1974 from the production for 300 MWe THTR confirm all results as expected. Special attention is paid to fuel elements with LEUTRISO particles that are being tested since 1982. Their excellent retention behaviour at hot-gas temperatures up to 950 deg. C is confirmed by the presently especially low coolant-gas activity. Because of the low burn-up of these elements it is still too early to make conclusive statements

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key words: Gas Cooled Reactor, Nuclear Technology
Reference:
Specialists' meeting on gas-cooled reactor fuel development and spent fuel treatment Moscow (Russian Federation) 18-21 Oct 1983
International Atomic Energy Agency, International Working Group on Gas-Cooled Reactors, Vienna (Austria); State Committee on the Utilisation of Atomic Energy of the USSR, Moscow (Russian Federation)
IWGGCR--8, pp:161-173