At the Karlsruhe Institute of Technology three high temperature liquid metal test facilities have been developed in the frame of the Helmholtz AMTEC Center (HAC), which is imbedded in Helmholtz Energy Material Characterization Platform (HEMCP). The motivation for the usage of liquid metals is based on the innovative concept proposed for Concentrating Solar Power . The requirements for the qualification of new materials for high temperature applications on a long term basis could not be fulfilled by a single test facility. Therefore, several universal scientific infrastructures, the SOdium Loop for TEst materials and Corrosion facilities (SOLTEC) have been designed, each facility allowing to operate with a dedicated test section .
The core facility for SOLTEC-1 and SOLTEC-2 consists of two sections, the high temperature side with temperatures up to 1000 K connected to the test section and the low temperature side (< 773 K), where the flow meter and the pump are located. Nickel based steels are foreseen for the high temperature side, while conventional stainless steel is used for the low temperature side. At the interface between both regions a heat recuperator has been combined with a Na-air heat exchanger. All facilities have a permanent magnet pump that drives the sodium into the test section at a maximal mass flow rate of 300 kg/h. Several safety measures have been considered from the design phase and all facilities are designed to operate autonomously with passive fail safe option, allowing a fast emergency drainage and even component failure does not lead to significant fire damages.
SOLTEC-1 (see Fig. 1) serves for a unique in situ low cycle fatigue (LCF) investigation of new materials for high temperature applications, such as the tube receiver in Concentrating Solar Power (CSP) plants. The behaviour of innovative tungsten laminated compounds  and ductile refractory materials are planned to be investigated at high temperature. A universal test machine and a high temperature vacuum oven are considered to allow long term and fail safe experiments.
|Figure 1. SOLTEC-1 facility connected with its test oven placed on a universal test machine|
SOLTEC-2 (see Fig. 2) will be used for investigations of steel erosion and corrosion in flowing hot Na environment under rapid temperature transients (ΔT~ 650-900°C). Further, the long term investigation of the stability of protective surface coatings (in/outer surface) using pulsed electron beams (GESA-SOFIE – Surface Optimization facility with Fast In-situ diagnostic Equipment ). The facility is at the end of the qualification phase, and has gathered several hours of operation at the maximal temperature of ~700°C.
|Figure 2. SOLTEC-2 facility connected with its test chamber|
SOLTEC-3 facility (see Fig. 3) will be employed for long term investigations of sodium based thermoelectrical converters , allowing the test of single cells, small and stacked modules. The experimental campaign will be focused also on the qualification of metallic/ceramic materials and joints for such converters. The test side of SOLTEC-3 is laid out up to 1220 K, while the cooling side is held below 773 K