# Senior Principal Mechanical Engineer* Nuclear* Permanent /* Warrington* United Kingdom* 11/06/26* On site* ShareI apply##Today, Assystem is among the top three independent nuclear engineering firms worldwide. With over 60 years of experience in highly regulated sectors, the group supports public and industrial stakeholders in the execution of complex and strategic infrastructure projects, subject to high safety and security requirements. Assystem mobilizes 8,000 experts in 13 countries and intervenes across the entire project lifecycle, in engineering, project management and digital solutions.## Job Description **Join the Fusion and Modular Nuclear Business Unit!** Take on a pivotal role in shaping the future of clean energy by establishing, leading, and managing the Cooling Water Island engineering team within a groundbreaking Small Modular Reactor (SMR) development program. Drive the development of a high-performing team, overseeing the design, integration, and execution of criti...