Collection of ENEA technology and expertise
Liquid led loop HELENA (Heavy Liquid metal Experimental loop for advanced Nuclear Application)
Application sectors
Problem to solve
The use of the HELENA facility aims to address several issues and meet crucial needs in the design and validation of advanced technologies for lead-cooled nuclear reactors (Lead Fast Reactors - LFR). Some of the main objectives include: 1. Improving the understanding of thermo-hydraulic properties in heavy liquid metals (Pb): The facility allows for in-depth study of the thermo-hydraulic behavior of systems operated with liquid lead, which is essential for the efficient cooling of LFR reactors and ensuring safe and optimized operational conditions. 2. Characterization of corrosion on structural materials: The facility addresses the need to understand how structural materials in contact with liquid lead can undergo corrosive processes, a critical issue for the long-term durability and safety of nuclear reactors. 3. Study of vibrations induced by lead flow: The facility is used to study the vibrations that the lead flow can generate as it passes through nuclear fuel rods.
Description
The primary circuit, operating with pure lead, consists of 2 ½” piping. Forced circulation within the system is achieved by a horizontal shaft centrifugal pump operating in the flow range of 10-50 kg/s and a head of 3.5-5 bar. The heat exchanger connecting the primary and secondary circuits is a shell & tube type heat exchanger with 7 bayonet tubes, with the gap filled with steel powder to reduce the mechanical stress in the heat exchanger tubes caused by the thermal gradient between the primary and secondary circuits. The heat exchanger is designed to remove a maximum power of 250 kW. The secondary circuit consists of a pressurized water loop designed for a maximum pressure of 100 bar and a temperature of 350°C.
Innovative aspects and advantages
- It allows the study of vibrations induced by the flow in lead
- With some modifications to the facility, the circuit can be used to study corrosion in flowing lead at higher temperatures, typical of Pb-cooled reactors.
- Expertise in the design of experimental facilities for material characterization tests
- Extensive experience in studying material characterization phenomena
Admissible applications
- Qualification of components (heat exchangers, valves, forced circulation systems, etc.), instrumentation in Pb, and generation of experimental data for the verification and validation of thermo-hydraulic and structural calculation codes
- Study of corrosion on materials in flowing lead.
- Study of oxygen removal systems from liquid lead under flowing. conditions
- Study of vibrations induced by lead flow on a fuel assembly.
- Thermo-hydraulic tests on mock-ups of fuel assemblies in both nominal geometric conditions and deformed configurations.
Research group involved
Revision date
28-05-2025
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