There has recently been growing interest in the development of innovative nuclear technologies that offer greater sustainability and cost effectiveness of electricity production. One of the most promising options is the lead fast reactor (LFR) technology. Lead stands out for its favorable neutron properties, allowing a hard neutron spectrum core as well as good shielding, heat transfer, and radioisotope retention capabilities. As lead has a boiling point in excess of 1700°C and does not react exothermically with either air or water, it also allows for the design of a low-pressure reactor block without an intermediate cooling circuit, which is used in other advanced reactor technologies for protecting against the interaction between primary and power conversion system coolants. The deployment of a new fleet of fast reactors is conditional on the control/prevention of the corrosion and erosion effects of the coolant against the structural materials, the systematic characterization of the interaction phenomena between the coolant and fuel and water, and the experimental qualification of innovative systems and components.

To support LFR technology development, the UK Department for Business, Energy & Industrial Strategy has recently allocated 10 M£ to a team composed of Westinghouse Electric Company LLC, the Ansaldo Nuclear Group, the Italian National Agency for New Technologies, Energy and Sustainable Economic Development, the University of Manchester, and other organizations for the design, construction, and first operation of a network of eight test infrastructures widespread in the United Kingdom to address the LFR’s highest priority research and development needs.

One of the experimental rigs is the Versatile Loop Facility (VLF) currently under construction at the Ansaldo Nuclear Group’s workshop in Wolverhampton, United Kingdom. The plant consists of a lead loop operable up to 650°C and equipped with a 500-kW electric fuel bundle simulator (resembling the Westinghouse LFR bundle) and a hybrid microchannel-type diffusion-bonded heat exchanger (which simulates the primary heat exchanger adopted in the Westinghouse LFR design). The heat removal is delegated to a supercritical water-cooling loop having a design pressure of 330 bar and maximum operating temperatures up to 620°C. In this paper we present the design of the VLF with specific details about its prototypical components and an insight into the construction and installation phases currently underway.