CERTIFIED SEISMIC DESIGN RESPONSE SPECTRA AND TIME HISTORY GENERATION FOR ADVANCED REACTOR LICENSE SUBMITTAL

摘要

This paper presents a summary of the work performed to develop certified seismic design response spectra (CSDRS) and compatible acceleration time histories for designing small modular reactors (SMRs) developed by NuScale Power. The intent is to submit the design to the United States Nuclear Regulatory Commission (NRC), and the CSDRS will be used to design the systems, structures, and components (SSCs) for a generic site design control document (DCD). Historically, when submitting a license for generic nuclear power plant (NPP) design vendors utilized the response spectra described in Regulatory Guide 1.60 and anchored the zero period acceleration (ZPA) at 0.3g. This approach, while technically sound typically resulted in some rework when actual site specific data was available, usually in the combined operating license process; the spectral shape from generic spectra varied from the spectral shape of the site specific spectra. As such an effort was undertaken to envelope actual site specific spectra with the intent to develop a more realistic and bounding CSDRS for the licensing of new nuclear power plants (NPPs) at generic sites. In addition, the reactor building for the NuScale power plant is a deeply embedded structure. For performing seismic soil-structure interaction (SSI) analysis to determine the seismic design responses, synthetic time histories need to be developed to match the target seismic response spectra. For the design, the target response spectra are the CSDRS and Generic High Frequency Hard Rock Response Spectra (GHFHRRS). The synthetic time histories are based on criteria from ASCE/SEI 43-05 and the NRC Standard Review Plan (NUREG 0800) Section 3.7.1. The spectral amplitudes resulting from the synthetic time histories are compared with the target spectra for 5% damping and found acceptable to meet the criteria. The range of frequencies considered is from 0.1 Hz to 100 Hz for the CSDRS and 0.1 Hz to 120 Hz for GHFHRRS. The total duration of the synthetic time history is 24 seconds. All three orthogonal (North-South, East-West and Vertical) synthetic time histories are statistically independent, meeting the cross coupling coefficients to be far less than the acceptable value of 0.16.