Session: MF-13-01 Composite and Non-Metallic Systems for Pressure Vessels and Piping

Paper Number: 106518

106518 - Considerations for Graphite in the Design and Qualification of Advanced Reactor Cores 

Graphite has been used historically in nuclear reactor cores for its excellent neutron moderation properties. However, the complex material behaviour inherent in irradiated graphite has resulted in several structural integrity challenges that has constrained the lifetime of the reactor core. Working towards understanding how graphite behaves in irradiated core conditions and its safety performance has allowed for the successful life extension of the UK AGR fleet to operate beyond their original design limits. Some of the key challenges with graphite is that due to its heterogeneity, the material behaviour is complex which is compounded when considering the irradiated environment; where degradation changes the material behaviour, leading to differential shrinkage and significant tensile stresses. This in turn affects the structural performance, and thermal hydraulics all of which have a consequence to the safe operation of the reactor core. Therefore, serious consideration of graphite in the design of next generation reactors will not only primarily secure safety in the design but could also reduce cost and increase the return on investment. Here, we identify seven main considerations for graphite in the design and qualification of advanced reactor cores that will aid in design code (specifically ASME III Division 5) and regulator conformance, but also improve the commercial viability of future nuclear power.

Presenting Author: Owen Booler Jacobs

Presenting Author Biography: A Senior consultant working in structural integrity with 15 years experience as a graphite specialist. Main focus has been stress analysis and crack propagation in irradiated graphite components. Developing bespoke solutions to customers key challenges.

Authors:

Owen Booler Jacobs
Mike Davies Jacobs