Contributors: John Jones, Andrew Buchan and Ali Tehrani
Published in Nuclear Future 22.6
The UK's transition towards net-zero carbon emissions will require a substantial increase in electricity generation alongside the widespread electrification of energy use. While renewable energy sources such as wind and solar will play a central role, their variable output presents challenges for maintaining a reliable electricity supply. The paper examines the UK's changing energy market, the limitations of energy storage and hydrogen, and the potential for nuclear power to provide reliable, low-carbon electricity through more flexible operation.
Conventional nuclear power stations are primarily designed for baseload generation, creating technical and economic challenges when adapting to fluctuating electricity demand. Small Modular Reactors (SMRs) offer opportunities for more flexible nuclear generation, but effective load-following requires improvements in reactor core design, axial power stability and control rod worth. The paper explores these challenges in Pressurised Water Reactors (PWRs), highlighting how fuel zoning and core design modifications can improve reactor performance and operational flexibility.
The paper presents a preliminary assessment of fertile inserts in PWR fuel assemblies as a method of improving control rod worth. Using reactor modelling and neutronic analysis, the authors investigate how inserting fertile materials into selected guide tubes can improve reactivity control. The results indicate that fertile inserts could increase control rod worth by approximately 9%, offering a potential approach to supporting more flexible nuclear generation and future SMR development.
DR JOHN JONES
Dr Jones is a Technical Director of Fairlie Associates and author of Nuclear Reactors Explained. Previously, he had technical lead responsibilities for fuel and core assessment at the Office for Nuclear Regulation and LWR fault analysis at EDF Energy. He was responsible for analysis supporting the first fuel reload at Sizewell B and taught fluid mechanics at the Royal Naval College, Greenwich.
DR ANDREW BUCHAN
Dr Andrew Buchan is a Senior Lecturer in Engineering Science at Queen Mary University of London. His research specialises in computational modelling, neutron transport, fluid flow and heat transfer, with applications in reactor physics, radiation shielding, criticality safety and nuclear accident analysis. He previously held research and teaching positions at Imperial College London.
PROFESSOR ALI TEHRANI
Professor Ali Tehrani FIMechE, FNucl, CEng is a nuclear safety specialist with experience in reactor safety, severe accident analysis, thermal hydraulics and regulatory assessment. He serves as a Principal Nuclear Safety Inspector with the UK Office for Nuclear Regulation and is a Visiting Professor at Imperial College London and Queen Mary University of London.