MOS Project

For R&D in thermalhydraulics of experimental reactor devices, the availability of data on local flowmeter values is essential to understand the flow distribution in the reactor vessels of nuclear reactors operated by EDF. Unfortunately, for high-temperature (up to 300°C) and high-pressure (up to 150 bar) flows in narrow passages above the Pressurized water reactor (PWR) core with optical access, the local measurement of these flow rates is currently impossible in operating nuclear reactors. It is often necessary to compare global data access for nuclear reactors with the simulation obtained from experimental data produced at the CEA.

The initial idea of the project is to design a multiphysics measurement sensor (flow, temperature, and pressure) using optical fibers to measure water flow in fuel assemblies in the core of nuclear reactors.

The measurement principle will consist in designing and using fiber Bragg gratings to recover the pressure, temperature and blade rotation values of a customized turbine flow meter to determine the flow characteristics (flow rate, density, Reynolds numbers, etc.).

The objectives of the project are the following:

• designing a pressure sensor based on FBG and compatible with the experimental facility,
• carrying out the design of a first prototype of MOS sensor,
• manufacturing the suitable FBGs,
• manufacturing the mechanical support for MOS sensor,
• assembling the sensor,
• adding the suitable interface for experimental tests,
• carrying out demonstration tests at room temperature and low pressure,
• identifying design improvements following demonstration tes