Search

In the European and international framework, ENEA coordinates the Italian fusion program, supported by linked third parties as universities, research institutes and industries. In this context, the Experimental Engineering Division (FSN-ING) is involved in experimental and numerical activities related to Breeding Blanket (BB) and Divertor technologies development. This paper describes the scientific works presently ongoing at Brasimone R.C. enveloped in LLE, lithium, helium, tritium and pressurized water technologies, characterization of structural materials, analysis of materials corrosion rate and development and qualification of anti-permeation/corrosion barrier. The experimental activities conducted for the investigation of safety-relevant scenarios as In-Box LOCA (LLE-water interaction in the WCLL or shock waves propagation generated by helium injection in LLE in the HCLL/DCLL-BBs) are here reported. Finally, new activities have been planned to support the Divertor Tokamak Test divertor characterization, the large-scale LLE-water interaction and a LLE components validation in relevant scale for WCLL-BB.

The NEXTOWER H2020 EU project investigates the possibility of using liquid lead as heat storage medium for high-temperature Thermal Energy Storage (TES) in concentrated solar power plants. To that end, within such project, a demonstration TES unit named SOLEAD (SOlar LEAd Demonstrator) is being developed to be coupled with an open volumetric air receiver in a solar tower CSP system. The SOLEAD demonstrator will use pure lead as working fluid and will be tested stand-alone, to address structural material behaviour at very high temperature, without coupling with air receiver. The tests are planned by the ENEA Brasimone R.C. in Italy. The introduction of the paper provides a general summary of the TES and CSP technology. Then a section is devoted to the conceptual design of SOLEAD. In the lead stand-alone experiment, the focus is on the materials corrosion in lead environment. Although the thermal stratification in the main vessel cannot be reproduced in a stand-alone experiment, the thermal cycle of the facility in the range 600-750°C will be properly reproduced in the experimental test. To this aim, external heating cables will heat up the system from 600°C to 750°C, while a proper Air Cooling System (ACS) will cool down the lead pool. A section of the paper contains the design criteria and calculation of the ACS with the air flowing on an annular gap between the vessel and the insulation. The power provided and extracted by the two systems (heating cables and ACS) is around 30 kW, so that the temperature range 600-750°C can be covered in about 8 hours and a complete cycle can be carried out in one day. Finally, a brief summary of the operational procedures needed from lead melting to the materials inspection is provided. The plan is to test the vessel for 4 months with daily thermal cycles to assess the resistance of FeCrAl materials exposed to very high temperature lead.

Corrosion phenomena of structural material in Lead-Lithium Eutectic (LLE) environment is influenced by the coolant chemistry, temperature, velocity profile and impurities concentration dissolved in it. In the framework of the EUROfusion consortium, the Experimental Engineering Division (FSN-ING) by the ENEA Brasimone Research Centre (RC) is developing scientific activities to investigate the corrosion rate of materials and to test Al based diffusion coating at 550 °C, different velocities (0.01, 0.1 and 1 m/s) and different exposure times. To this end, a new experimental facility, named LIFUS II (Lithium for Fusion II) is under construction at the Brasimone RC laboratories. Piping and components installed in the hot leg of the facility are internally coated by an Al based diffusion coating developed in collaboration with RINA Consulting-CSM to reduce concentration of corrosion product in the loop. A preliminary screening of the coating was performed in LLE stagnant conditions at 550 °C for 1000 h showing a good resistance and no signs of dissolution were detected. The only modification on the surface was found to be related to the formation of dark islands made of Al2O3.

Oxygen sensors for Heavy Liquid Metals (HLMs) such as lead and LBE (lead-bismuth eutectic) will be essential devices in future Lead Fast Reactor (LFR) and Accelerator Driven System (ADS). Potentiometric sensors based on solid electrolytes were developed in recent years to this purpose. Internal reference electrodes such as Pt-air and Bi/Bi 2 O 3 liquid metal/metal-oxide are among the most used but they both have a weak point: Pt-air sensor has a high minimum reading temperature around 400 °C whereas Bi/Bi 2 O 3 suffers from internal stresses induced by Bi volume variations with temperature, which may lead to the sensor failure in the long-term. The present work describes the performance of standard Pt-air and Bi/Bi 2 O 3 sensors and compares them with recent Cu/Cu 2 O sensor. Sensors with Yttria Partially Stabilized Zirconia (YPSZ) electrolyte were calibrated in oxygen-saturated HLM between 160 and 550 °C and the electric potential compared to the theoretical one to define the accuracy and the minimum reading temperature. Standard Pt-air sensor were also tested using Yttria Totally Stabilized Zirconia (YTSZ) to assess the effect of a different electrolyte on the minimum reading temperature. The performance of Pt-air and Cu/Cu 2 O sensors with YPSZ electrolyte were then tested together in low-oxygen HLM between 200 and 450 °C. The results showed that Pt-air, Bi/Bi 2 O 3 and Cu/Cu 2 O sensors with YPSZ measured oxygen in HLMs down to 400 °C, 290 °C and 200 °C respectively. When the YTSZ electrolyte was used in place of the YPSZ, the Pt-air sensor measured correctly down to at least 350 °C thanks to the superior ionic conductivity of the YTSZ. When Cu/Cu 2 O and Pt-air sensors were tested together in the same low-oxygen HLM between 200 and 450 °C, Cu/Cu 2 O sensor worked predictably in the whole temperature range whereas Pt-air sensor exhibited a correct output only above 400 °C.

Spine pain is one of the most common pain conditions, with low back pain representing the second leading cause of disability worldwide. It has a great impact on functional capacity and occupational activities, representing a major welfare and economic problem. Main causes of back pain include intervertebral disc pathologies, facet joint pain, dynamic instabilities, spondylosis and stenosis, spondylolisthesis, osteoporotic compression fractures, spinal infections and others. Even though some of these conditions have a well-defined clinical presentation, others may present with heterogeneous signs and symptoms that may render differential diagnosis arduous.

Since Lead-cooled Fast Reactors (LFR) have been conceptualized in the frame of Generation IV International Forum (GIF), great interest has focused on the development and testing of new technologies related to Heavy Liquid Metal (HLM) nuclear reactors. In this frame, ENEA developed one of the larger European experimental fleet of experimental facilities aiming at investigating HLM thermal-hydraulics, coolant chemistry control, corrosion behavior for structural materials, and at developing components, instrumentations and innovative systems, supported by experiments and numerical tools. The present work aims at highlighting the capabilities and competencies developed by ENEA so far in the frame of the liquid metal technologies for GEN-IV LFR. In particular, an overview on the ongoing R&D experimental program will be depicted considering the actual fleet of facilities: CIRCE, NACIE-UP, LIFUS5, LECOR and HELENA. CIRCE (CIRColazione Eutettico) is the largest HLM pool facility presently in operation worldwide. Full scale component tests, thermal stratification studies, operational and accidental transients and integral tests for the nuclear safety and SGTR (Steam Generator Tube Rupture) events in a large pool system can be studied. NACIE-UP (NAtural CIrculation Experiment-UPgraded) is a loop with a HLM primary and pressurized water secondary side and a 250 kW power Fuel Pin Simulator working in natural and mixed convection. LIFUS5 (lithium for fusion) is a separated effect facility devoted to the HLM/Water interaction. HELENA (HEavy Liquid metal Experimental loop for advanced Nuclear Applications) is a pure lead loop with a mechanical pump for high flow rates experiments. LECOR (LEad CORrosion) is a corrosion loop facility with oxygen control system installed. All the experiment actually ongoing on these facilities are described in the paper, depicting their role in the context of GEN-IV LFR development. © 2018 Elsevier Ltd