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Title: Light Water Reactor Sustainability Program Advanced Seismic Soil Structure Modeling

Risk calculations should focus on providing best estimate results, and associated insights, for evaluation and decision-making. Specifically, seismic probabilistic risk assessments (SPRAs) are intended to provide best estimates of the various combinations of structural and equipment failures that can lead to a seismic induced core damage event. However, in some instances the current SPRA approach has large uncertainties, and potentially masks other important events (for instance, it was not the seismic motions that caused the Fukushima core melt events, but the tsunami ingress into the facility). SPRA’s are performed by convolving the seismic hazard (this is the estimate of all likely damaging earthquakes at the site of interest) with the seismic fragility (the conditional probability of failure of a structure, system, or component given the occurrence of earthquake ground motion). In this calculation, there are three main pieces to seismic risk quantification, 1) seismic hazard and nuclear power plants (NPPs) response to the hazard, 2) fragility or capacity of structures, systems and components (SSC), and 3) systems analysis. Two areas where NLSSI effects may be important in SPRA calculations are, 1) when calculating in-structure response at the area of interest, and 2) calculation of seismic fragilities (current fragility calculations assumemore » a lognormal distribution for probability of failure of components). Some important effects when using NLSSI in the SPRA calculation process include, 1) gapping and sliding, 2) inclined seismic waves coupled with gapping and sliding of foundations atop soil, 3) inclined seismic waves coupled with gapping and sliding of deeply embedded structures, 4) soil dilatancy, 5) soil liquefaction, 6) surface waves, 7) buoyancy, 8) concrete cracking and 9) seismic isolation The focus of the research task presented here-in is on implementation of NLSSI into the SPRA calculation process when calculating in-structure response at the area of interest. The specific nonlinear soil behavior included in the NLSSI calculation presented in this report is gapping and sliding. Other NLSSI effects are not included in the calculation. The results presented in this report document initial model runs in the linear and nonlinear analysis process. Final comparisons between traditional and advanced SPRA will be presented in the September 30th deliverable.« less
Authors:
 [1] ;  [1]
  1. Idaho National Lab. (INL), Idaho Falls, ID (United States)
Publication Date:
OSTI Identifier:
1235205
Report Number(s):
INL/EXT--15-35687
TRN: US1600234
DOE Contract Number:
AC07-05ID14517
Resource Type:
Technical Report
Research Org:
Idaho National Laboratory (INL), Idaho Falls, ID (United States)
Sponsoring Org:
USDOE Office of Nuclear Energy (NE)
Country of Publication:
United States
Language:
English
Subject:
54 ENVIRONMENTAL SCIENCES; 58 GEOSCIENCES; NUCLEAR POWER PLANTS; WATER MODERATED REACTORS; SOILS; WATER COOLED REACTORS; HAZARDS; CRACKS; EARTHQUAKES; FAILURES; FOUNDATIONS; GROUND MOTION; NONLINEAR PROBLEMS; PROBABILISTIC ESTIMATION; SEISMIC WAVES; DILATANCY; LIQUEFACTION; PROBABILITY; SIMULATION; SUSTAINABILITY; RISK ASSESSMENT; SEISMIC ISOLATION; SYSTEMS ANALYSIS; WAVE PROPAGATION; DAMAGE; EQUIPMENT; BUILDINGS; IMPLEMENTATION; MATHEMATICAL MODELS; SOIL-STRUCTURE INTERACTIONS; SEISMIC SURFACE WAVES seismic; soil structure