VELLA WORLD
ONGOING ACTIVITIES ON HLM IN EUROPE
A wide use of pure lead, as well as its alloys (such as lead-bismuth), is foreseen in several nuclear-related fields: it is studied as coolant in critical and sub-critical nuclear reactors, as spallation target for neutrons generation and for tritium generation in fusion systems.
Given this possible future extensive employment of lead in nuclear systems, therefore, a deep understanding of its physics and engineering is needed.
As a consequence large efforts are devoted worldwide to various areas of interest, from the material qualification, to thermal-hydraulic studies, component development and testing and so on.
Focusing on the fission-oriented research area, important R&D programmes are dedicated to the Generation IV LFR concept development, from the U.S. LFR Program, focused on the development of a small transportable reactor system for international deployment, to the European ELSY (European Lead-Cooled System) project, aimed at showing the possibility of realization and operation of a safe and competitive fast lead-cooled critical reactor.
Wide importance is given to the activities in support of the development of systems for the transmutation of radioactive waste, as can be noticed from the European Union (EU) projects as EUROTRANS (EUROpean research programme for the TRANSmutation of high level nuclear waste in Accelerator Driven Systems), which concurs to demonstrate the feasibility of an ADS-type dedicated transmuter and MEGAPIE-TEST (MEGAwatt PIlot Experiment), which has been a first decisive step to design and operate a liquid metal spallation target at PSI, Villigen, with a high-energy proton beam SINQ. Successful completion of the project has demonstrated the feasibility, licensing and a fairly long-term operation under realistic conditions of a high power spallation target.
In parallel, project dedicated to address specific issues have been and still are carried out, as, for example, considering the EU framework programmes, TECLA (TEChnologies for Lead Alloys), dedicated to lead technologies, aimed at assessing the use of lead alloys both as a spallation target and as a coolant for an ADS, ASCHLIM (ASsessment for computational Codes in Heavy LIquid Metal flows), aimed at sharing experience in the field of computational fluid dynamics codes applicable to HLM and their benchmarking, SPIRE, devoted to addressed the irradiation effects specific to spallation target environment on basic in-service properties, VELLA (Virtual European Lead LAboratory) , aimed at integrating the existing European HLM infrastructures, developing synergies and complementarities among the laboratories and the research groups across the EU.
Studies dedicated to material and component development as well as to HLM (Pb-17Li) technologies and thermal-hydraulics are going on, moreover, in the main fusion-oriented international research programmes.
In this framework, four main areas of investigation can be identified:
SYSTEM AND COMPONENT DEVELOPMENT