Activities on HLM Technologies at Research Center Karlsruhe

Georg Müller

Forschungszentrum Karlsruhe

Institute of Pulsed Power and Microwave Technology

At Forschungszentrum Karlsruhe (FZK) the characteristics of an accelerator-driven subcritical system (ADS) are evaluated, mainly with respect to the potential of transmutation of minor actinides and long-lived fission products, to the feasibility and to safety aspects. All experimental activities, which are related to lead-bismuth as cooling fluid and spallation material, are performed in the KArlsruhe Lead LAboratory KALLA.

This presentation gives an overview on KALLA, which has three experiments with stagnant HLM and three loop experiments. The stagnant experiments focus on corrosion mechanisms, surface treatment, oxygen sensor development, and oxygen control system (OCS), the loop experiments on thermalhydraulic measurement techniques, ADS-relevant component testing, and corrosion investigations in flowing lead-bismuth.

The second part of the presentation deals with the phenomenon of steel corrosion by HLM on a theoretical and experimental basis and on improvement of the corrosion behavior by surface alloying. Thermaldynamic considerations show the relations between the oxygen partial pressure in the gas phase and the oxygen concentration in HLM and its influence on the corrosion behavior. The electron beam facility GESA is described which is employed to alloy aluminum into the steel surface. The changes in material composition at the surface are shown. Tests with original and surface alloyed steels in stagnant and flowing HLM indicate their suitability for the HLM technology under several conditions relevant for ADS and nuclear reactor application.