Mitigating seismic damage of nuclear reactors
Work has started on the development of Generation IV (Gen IV) nuclear reactors, which will come online in the next 10 years. Among these, lead-cooled fast reactors (LFRs) require particular improvements in safety standards before they can be built. The EU-funded project SILER(opens in new window) (Seismic-initiated events risk mitigation in lead-cooled reactors) performed a study into the risks associated with seismic-initiated events in Gen IV reactors, and developed adequate protection measures. The focus was on developing and applying mitigation strategies such as seismic isolators for LFRs. Project partners performed a thorough examination of the risks and consequences associated with external dynamic loads on LFRs by analysing the behaviour of the plants under seismic conditions. Specific layout solutions were suggested and suitable seismic isolators were manufactured, together with the related interface components. These included flexible joints for pipelines and cover joints to protect the seismic gap surrounding the isolated portion of the plant. For the first time, seismic isolators such as high damping rubber bearings and lead rubber bearings were tested using real 3D dynamic excitations to define the safety margins. In addition, project partners developed suitable flexible joints for the pressurised hot steam pipeline that leads to the turbine building. This is the most critical pipeline, crossing the seismic gap between the isolated and non-isolated parts of the plant. SILER drew up guidelines and recommendations for the design, qualification, in-service inspection, maintenance and replacement of isolators. The project also placed focus on transferring the generated knowledge to sodium fast reactors as well as Gen III advanced nuclear reactors. Standardisation of seismically isolated nuclear reactors should have a positive impact on the economics of next-generation reactors. By providing safe designs of seismic isolators for LFRs, SILER facilitates the EU move to a competitive low-carbon economy by 2050.
