# Design of the CIEMAT Corrosion Loop for Liquid Metal Experiments
## 3 CiCLo-C Loop: Requirements and Design
### Main Components and Functioning  
The main components of the loop are indicated in Figure 1 and described in Table 1. \begin{table}
\begin{tabular}{l l} \hline \hline  & **Main Components** \\ \hline
1 & Fluid temperature measurement \\ \hline
2 & Connection to level probes \\ \hline
3 & Connection to argon supply \\ \hline
4 & Expansion tank S-001 \\ \hline
5 & Loop pipes \\ \hline
6 & Test section (TS) \\ \hline
7 & Heat exchanger air outlet \\ \hline
8 & Pneumatic ball valve \\ \hline
9 & System filling line \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Main components of the loop, as indicated in Figure 1.  
The liquid metal loop has the main operating parameters indicated in Table 2. These parameters were selected considering the worst extreme conditions for a breeder blanket. Of course, it is possible to work in softer regimes and perform specific tests for less demanding scenarios. A description of the main components presented in Figure 1 and Table 1 is detailed below. \begin{table}
\begin{tabular}{l l} \hline \hline
**Parameters** & **Values** \\ \hline Temperature of the liquid PbLi & Max 600 \({}^{\circ}\)C \\ \hline Volume flow of the loop & Max 0.5 L/s \\ \hline Static pressure & Max 3 bar \\ \hline Capacity PbLi & 7 L \\ \hline Gase value & Pressurized air 10 bar/argon 3 bar \\ \hline Dimensions & 2360 \(\times\) 2790 \(\times\) 900 (height \(\times\) length \(\times\) width) \\ \hline Total weight & app. 700 kg \\ \hline Inner diameter & 32 mm \\ \hline Outer diameter & 38 mm \\ \hline \end{tabular}
\end{table} 
Table 2: Main features of CiCLo-C.  
Figure 1: 3D sketch of the CiCLo-C facility. A _permanent magnetic pump_ (PMP) from SAAS GmbH is responsible for the lithium lead circulation inside the loop. It has a rotor diameter of 250 mm, a power of 3 kW, and a rotation speed varying between 70 and 705 rev/min. It can work at up to 600 \({}^{\circ}\)C, and as visible from Figure 2, it can supply different flow rates at different working pressures. Thus, the PMP supplies a range of PbLi velocities in the TS from 0.2 m/s to 2.5 m/s. The _draining tank_ is responsible for recollecting all the liquid metal previously molted. It is provided by a cap and side hook because in this way, it can be removed directly with all the contaminated lead lithium once the experimental campaign is finished. For this purpose, the tank was designed with a slope at the bottom, which facilitates the evacuation of the liquid metal through a drain valve. This drain valve will also be used to extract samples of PbLi during the experimental campaign. With periodic analysis of the liquid metal, it will be possible to have an indirect measurement of how corrosion is acting and identify the presence of a small leak or any possible contamination. At the bottom, a rail system permits movement in the horizontal direction to compensate for the thermal expansion of the whole loop (see Figure 3). An additional _expansion tank_ is placed at the top of the loop for filling purposes and to compensate for changes in the level of the liquid metal (Figure 1). Figure 3: Details of the rail system of the draining tank, which permits movement due to thermal expansion. Figure 2: Pressure vs. flow rate variation characteristic curves of the permanent magnetic pump, by SAAS GmbH. The _flow meter_ is a magnetic flywheel one from SAAS GmbH and consists of three main components: mechanical, inductive proximity switch, and frequency and revolutions relay. It is described by the diagram in Figure 4a. The flow meter is powered by the fluid in the pipe situated above it. The rotation of the shaft is recorded by an inductive proximity switch and is subsequently analyzed by a frequency and rotation relay. For the use and calibration of this flow meter, is necessary to use a dedicated channel with a custom-made flat pipe (see Figure 4b). The magnets are made of SmCo alloy, and as the liquid metal flows, the magnet system rotates at a rotation speed proportional to the flow rate.