New design of a creep-rupture facility for tests in heavy liquid metals

摘要

Current nuclear research and development is focused on innovative strategies for safe and economic new reactor designs in optimised processes for nuclear waste management. First and foremost this promotes concepts which consider the minimization of e.g. minor actinides in spent nuclear fuel by transmutation of high level radioactive waste with high energy neutrons. Therefore, heavy liquid metals (HLMs) have gained immense interest as coolant and target in subcritical accelerator driven systems (ADS) and also as coolant in Gen IV-type lead-cooled fast reactors. The advantage of HLMs is their high thermal conductivity and their relative safety in case of an accident. Nevertheless, high operating temperatures together with a corrosive environment induce liquid metal embrittlement, corrosion, and erosion as well as pronounced irradiation damage. The combination of these crucial operating conditions is the motivation for the development of new structural materials for construction parts of such reactors.A goal of our research is to investigate the creep-rupture behavior of envisaged structural materials as well as to predict their service life-time under extremely corrosive conditions in oxygen-controlled liquid lead at elevated temperatures (>600°C). Furthermore, based on the results for short- and long-termed experiments under high and low stress conditions, respectively, it is expected to evaluate the margin factor of the corrosion process under creep conditions at elevated temperatures. In this study a new creep-rupture facility for tests in oxygen containing molten lead at elevated temperatures called CRISLA (Creep-Rupture in Stagnant Lead Alloys) which was designed in our laboratory is presented. Experimental results with a martensitic (DIN 1.4914) and an austenitic (DIN 1.4571) steel obtained in air at 650°C are confirming the operating efficiency of the facility. Furthermore, tests for the stable operating conditions, especially for oxygen-controlled lead, have been carried out.