FUSION REACTOR ASSESSMENT – FEA REDUCES TIMESCALES AND IMPROVES EFFICIENCY

SUMMARY

We were commissioned to provide expert analysis support on the design of the world’s largest nuclear fusion reactor. The assessment needed to meet the applicable project standards and consider a wide range of load cases, including unique cases caused by disruptions to the plasma field within the Tokamak. Our methodologies ensured it was possible to identify the exact failure loads and mechanisms. Design changes could then be instigated with confidence and from the basis of an in-depth understanding of the causes of failure.

SITUATION

Our client was part of the international team supporting the ITER fusion reactor project.  The ITER project aims to prove the viability of nuclear fusion as a sustainable energy source.  To this end, they are building the world’s largest nuclear fusion reactor in Caderache, France.  As a revolutionary project, with many engineering firsts, significant engineering input was required to ensure the design was structurally robust and fit for purpose.

Additionally, the unique technical and funding collaboration required to achieve this goal led to the development of a truly international team, with all of the subsequent challenges and benefits of language, culture and engineering approach.

CHALLENGE

We were asked to support the Tokamak team to assess the structural capacity of the Cryostat and the associated pedestal ring which supported the full 23,000 tonne mass of the reactor.  The assessment needed to meet the applicable project standards (ASME VIII Div.2) and consider a wide range of load cases, including both conventional and unique cases caused by disruptions to the plasma field within the Tokamak. The assessments needed to include: static structural strength, seismic assessment (OBE & DBE), thermal gradients and Vertical Displacement Events (VDE). Additionally, a detailed fatigue assessment of the structure was required.

SOLUTION

We were deployed to the client’s site in the south of France, for eight months, to provide expert analysis support as an integrated part of the Tokamak design team.  As it was early in the design stage, we understood that many updates and revisions would be required for the design to accommodate both functional and structural requirements. Using ANSYS Parametric Design Language (APDL), we created a fully parametric model of the Cryostat base and support structure. This approach allowed changes to be instigated in a matter of minutes, solving multiple iterations within a short timescale.   By utilising the elastic-plastic Design by Analysis (DBA) rules from ASME VIII Div. 2, it was possible to identify true failure loads and mechanisms.  On the basis of these results, our client could instigate design changes with confidence as an in-depth understanding of the causes of failure were determined. Once our client had completed the design,  we were responsible for authoring the detailed structural analysis.  While on site, we also supported multiple analysis tasks.

BENEFITS

• Reduced timescales, allowing additional work scopes to be completed by PDL engineers while on site.
• Access to Suitably Qualified and Experienced Personnel (SQEP) resource required to complete the tasks.