The paper focuses on the state of the art for the use of formal methods in the development of control systems in the nuclear sector. For decades, formal methods have been acknowledged as a very powerful set of techniques with potential to significantly improve the speed and quality of software deployment but usually requiring the use of rare and often expensive skills to deploy effectively. For this presentation, we used an open problem statement by Abrial. The case study was implemented using a team of professional software engineers and commercially supported tools. The paper highlights how the Abrial informal specification is used as the basis for the development of a set of System Requirements using structured English and how formalism is introduced through software requirements, design and code and used as the basis for automatic, independent verification. The exploration of desired properties at the requirements level is explored formally. The final aspect discussed is the potential for formal verification of the Executable Object Code. The possible claims for certification credit are also discussed. Using DO-333, a summary of the claims is provided, including limitations. Finally, metrics are presented, including the hours of effort expended on development and verification.