# Status, Features, and Future Development of the LIFUS5/Mod4 Experimental Facility Design
## 3 Materials and Methods
### Instrumentation  
#### 3.4.1 Instrumentation List and Description  
To produce significant and impactful data on the phenomena occurring during the in-box LOCA, the facility will be equipped with sensors to monitor all the relevant thermodynamical parameters and actuators to control them. The choice of the position and the requirements of the sensors are based on an extensive numerical simulation campaign in which code chain methodologies were implemented to correctly reproduce the underlying phenomena expected [17,23]. Sensors and actuators will be composed of:  
1. **Actuators:** 1. Heating wires for temperature control; 2. Regulation valves for flow control; 3. Safety valves and rupture disk for overpressure protection; 4. Inert gas distribution system for pressure regulation and oxidation protection; 5. Recirculation pump (foreseen to be installed after the first experimental phase and after the facility upgrade). 2. **Sensors:** 1. Thermocouples for temperature control; 2. Fast pressure transducers (10 kHz) for data acquisition of the pressure wave and fast pressure transients; 3. Absolute pressure transducers for pressure control; 4. Level meters for level monitoring inside the tanks; 5. Differential pressure meters for pressure loss monitoring and mass flow measurement; 6. Strain gauges for deformation measurement. The sensors are then subdivided into three different categories according to their function: * Control sensors. Used for control of the facility, they interact with the control system to allow the regulation of all the relevant parameters; * Safety sensors. These are used for safety purposes, such as controlling that the heating cables would not exceed the maximum allowed temperature; * Data acquisition sensors. They are used to acquire data on the phenomena occurring inside the facility. A recap of the sensors foreseen to be installed in the facility is shown in Table 2. Notice how one sensor can be assigned to more than one group at a time if, for example, it can serve both safety and acquisition purposes. All the sensors are positioned at critical points of the facility to allow the collection of significant data. In particular:  
* DP meters are positioned across all the critical components and piping section of the PbLi loop to measure the contribution to the pressure losses and dynamical behavior of the single components during the in-box LOCA transients. \begin{table}
\begin{tabular}{c c c c c} \hline \hline  & **Thermocouples** & **Level Meter** & **DP Meter** & **Pressure Gases** \\ \hline Total & 206 & 9 & 6 & 15 \\ Safety & 58 & 6 & 0 & 15 \\ Control & 116 & 3 & 0 & 6 \\ Acquisition & 32 & 3 & 6 & 9 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Recap of sensors mounted on the facility. * Fast pressure transducers will be mounted on the test section and the pipes of the pipe forest. This will allow the detection of pressure spikes inside the TBM mock-up and the measurement of the pressure waves traveling through the piping up to the TEU and recirculation tank. * Absolute pressure transducers will be mounted on the main tanks (recirculation, TEU, and relief tanks). Their main function will be to acquire data on how these free volumes can absorb and mitigate the pressure wave propagation throughout the system. Moreover, the reading of these sensors is usually less prone to drift than the fast pressure transducers, and thus it can be used as a calibration signal for these latter ones. * Strain gauges will be mounted inside the test section and on the pipe forest to acquire the deformation of these critical components. * Thermocouples will be placed both inside the test section and on the piping to acquire possible temperature fluctuations related to the release of energy due to the PbLi-water chemical interaction. * A hydrogen analyzer will be included in the system. It will be able to spill non-condensable gasses (Ar + H\({}_{2}\)) containing reaction products from all over the facility thanks to a dedicated piping and valve system.