The company

LeadCold Reactors (Blykalla Reaktorer) was founded in 2013 by J. Wallenius, P. Szakalos and J. Ejenstam as a joint stock company, with its basis in Stockholm. Our Canadian subsidiary is registered in Alberta, the Northwest Territories and Nunavut. 



LeadCold is a spin-off from KTH Royal Institute of Technology in Stockholm, where J. Wallenius carried out research on design and safety analysis on lead-cooled reactor systems since 1996. The competences of the LeadCold team include fast reactor core design, transient analysis, corrosion and materials science, nuclear fuel development, lead coolant chemistry, radiation damage and severe accident analysis. Through collaboration with KTH, the company has access to laboratories for lead corrosion studies, nuclear fuel manufacture, heavy liquid metal thermal hydraulics and severe accident experiments. The research at KTH is made in close collaboration with Swedish nuclear materials industry. 


Funding history

Seed funding for a market analysis of small lead-cooled reactors was provided to LeadCold by KTH Innovation in 2013. In December 2014, a grant for development of tools for safety informed design of lead-cooled reactors was given by VINNOVA (The Swedish Innovation Agency). In December 2015, KIC InnoEnergy invested in LeadCold, supporting further business development of the company. In June 2018, the UK government awarded LeadCold  a contract to produce a feasibility study for serial production of  its SEALER-UK concept.


Janne Wallenius

Reactor Physics

Peter Szakalos


Jesper Ejenstam


Scientific/Technical team

Sara Bortot

Safety Analysis

Staffan Qvist

Core Design

Ignas Mickus

System Design

Management team

Lars Franzén


Harald Klomp


Magnus Sjöland

Board Director

Anders Blennermark

Board Director

David Malcolm

Board Director


© LeadCold Reactors, 2019