Nuclear Energy and Waste


Ground-Motion Analysis and Soil-Structure-Interaction (SSI) Modeling

Nuclear energy is re-emerging both nationally and globally as a reliable and carbon-emission-free energy resource. Within the United States alone, the Nuclear Regulatory Commission (NRC) has been receiving letters of intent for license applications for dozens of new nuclear power plants. The potential for structural damage caused by a major earthquake is a critical design criterion for nuclear power plants. Existing nuclear power plants have been structurally designed and regulated based on tools that are more than two decades old, and invoke many simplifying assumptions. For increased efficiency and safety, more rigorous and realistic seismic simulation tools need to be developed, using modern solution algorithms and high-performance computing. Seismic analysis and structural design can be improved by (1) improved models for seismic wave propagation and ground-motion characteristics, (2) improved models for nonlinear structural system response, (3) improved models for soil-structure interaction, and (4) integration of the above. These issues are relevant in the context of designing and building new generation nuclear plants (relevant to industry), as well as being able to evaluate and regulate new plant applications (relevant to NRC).

LBNL researchers are currently supporting the NRC’s need for further technical information about a set of related technical topics. The main objective of the project is to develop the technical basis for new NRC staff guidance to applicants and licensees on critical issues related to the seismic analysis and design of new nuclear power plants (NPPs), in the broad area of time-domain soil-structure-interaction (SSI) modeling.  NRC possesses regulatory methods and has already developed regulatory positions on some of the topics under investigation, but not for all of them. The ultimate goal is to improve NRC licensing positions on these topics. NRC also needs regulatory analysis tools so that submittals from applicants and licensees in these topic areas can be reviewed. Three specific tasks are being conducted:

  • Investigation of methods to incorporate performance-based risk-informed techniques in the design of Structures, Systems, and Components (SSCs) of Nuclear Power Plants (NPPs)
  • Investigation of analysis methods to incorporate multi-dimensional loading and incoherent ground motion in soil-structure-interaction analyses
  • Development of NUREG/CR report on base isolation technology, design and assessment as it pertains to NPP SSCs.