Structural assessment of the contamination protection structure placed on the top of the DEMO bioshield roof

• Published in: Fusion engineering and design 2024-04, Vol.201, p.114292, Article 114292
• Main Authors: Marek, P., Sienkiewicz, M., Bachmann, Ch, Ciupiński, Ł.
• Format: Article
• Language: English
• Subjects: Bioshield; DEMO; Finite element method; Structural design
• ISSN: 0920-3796; 1873-7196
• DOI: 10.1016/j.fusengdes.2024.114292

In the DEMO power plant design, the bioshield roof above the tokamak is a steel structure with radial beams and concrete inserts. A contamination protection structure (CPS) is placed on the bioshield roof to protect other areas against the potential release of any radioactive materials from inside the reactor during maintenance. It also provides support to the cask, which is used to transfer the heavy blanket segments to the active maintenance facility (AMF). Herewith, the structural design of the CPS and the bioshield roof is investigated using parametrized FE models in the Ansys APDL environment. The results of the linear static analysis show that the stress in the CPS as well as in the structure of the bioshield roof is within the acceptable range. However, linear buckling analysis shows that the CPS may lose stability due to buckling. The proposed design modifications resulted in a structure that is sufficiently strong and rigid to withstand all load conditions. The analyses revealed that the actual loads acting on the bioshield roof structure, due to the CPS and its handling structures, are lower than assumed during its preliminary design, therefore it is possible to reduce the dimensions of the bioshield roof beams and girders in the future.