Introduction Gaps in SMR Design Summary

Civil and Structural Engineering Gapsin Small Modular Reactor Designs

Boris Jeremic (UCD/LBNL)with

Justin Coleman (INL) and Andrew Whittaker (UB)

ASME 2014 SMR Symposium

Coleman, Whittaker and Jeremic

Gaps in SMR Design

Introduction Gaps in SMR Design Summary

Outline

IntroductionOpportunities and Challenges

Gaps in SMR DesignModeling and Simulation Issues

Summary

Coleman, Whittaker and Jeremic

Gaps in SMR Design

Introduction Gaps in SMR Design Summary

Outline

IntroductionOpportunities and Challenges

Gaps in SMR DesignModeling and Simulation Issues

Summary

Coleman, Whittaker and Jeremic

Gaps in SMR Design

Introduction Gaps in SMR Design Summary

Opportunities and Challenges

SMR: Civil Structural Economic Opportunities

I SMRs present the opportunity to make investments innuclear power more affordable

I To capitalize on this economic potential SMR vendors needto:

I provide a design that is economically more affordable (perkilowatt hour) by:

I Maximizing the modularityI Minimizing regulatory risk by using standardizing

approaches for modular construction, seismic isolation, andseismic analysis

Coleman, Whittaker and Jeremic

Gaps in SMR Design

Introduction Gaps in SMR Design Summary

Opportunities and Challenges

SMR: Regulatory Challenges Related toStandardization

I Ideally vendors would have standardized methods to use inthe licensing process:

I Modular constructionI Seismic isolation of Structure, Systems, and Components

(SSCs)I Seismic analysis methods

I Standardized methods would minimize NRC questionsduring the licensing process

Coleman, Whittaker and Jeremic

Gaps in SMR Design

Introduction Gaps in SMR Design Summary

Opportunities and Challenges

SMR: Need for Appropriate Tools and Methods

I Seismic Analysis and Design to meet Performance GoalsI Analysis must be accurate, reducing modeling uncertaintyI Design must be consistent with codes and standardsI Produce designs that are conservative with respect to the

Earthquake Hazard

I Seismic Probabilistic Risk AssessmentI Want accurate (or best estimate) core damage frequency

numbers

Coleman, Whittaker and Jeremic

Gaps in SMR Design

Introduction Gaps in SMR Design Summary

Opportunities and Challenges

SMR: Seismic Challenges (from US-NRC)US-NRC DESIGN-SPECIFIC REVIEW STANDARD FORmPOWER iPWR DESIGN; (deeply embedded structures)

I Effect of deep embedment on the relative significance ofkinematic interaction

I The extent to which non-vertically propagating shear waves maybe more important for deeply embedded structures than forthose with shallow embedment depth

I The impact of deep embedment on the accuracy of side wallimpedance functions calculated with standard methods

I The effect of nonlinear behavior (e.g., separation of structureand soil, and soil material properties) on wall pressure and SSIcalculations;

I The variation of V/H (vertical to horizontal) spectral ratios onground motion over the depth of the facility.

Coleman, Whittaker and Jeremic

Gaps in SMR Design

Introduction Gaps in SMR Design Summary

Opportunities and Challenges

SMR: Challenges for DesignI Seismic performance goals for SMRsI Earthquake Soil Structure Interaction analysis of deeply

embedded structuresI Modeling of fluid-structure interactionI Seismic isolation of SMR components and systemsI Modular SC construction of SMR components and systemsI Uncertainty in material behavior, earthquake loads, &c.

(advanced seismic probabilistic risk assessment for SMRs)I Modeling uncertaintyI Protection of SMRs from man made hazard (aircraft

impact, &c.)I Regulatory guidance for the civil/structural design of SMRs

Coleman, Whittaker and Jeremic

Gaps in SMR Design

Introduction Gaps in SMR Design Summary

Outline

IntroductionOpportunities and Challenges

Gaps in SMR DesignModeling and Simulation Issues

Summary

Coleman, Whittaker and Jeremic

Gaps in SMR Design

Introduction Gaps in SMR Design Summary

Modeling and Simulation Issues

High Fidelity Modeling and SimulationSome soil-structure features of SMR are similar with LWRs

Coleman, Whittaker and Jeremic

Gaps in SMR Design

Introduction Gaps in SMR Design Summary

Modeling and Simulation Issues

Earthquake Soil Structure Interaction (ESSI)

I A number of ESSI modeling and simulation issues thatcontrol the seismic response

I Detrimental and Beneficial ESSI effectsI Seismic energy propagation and dissipation

Coleman, Whittaker and Jeremic

Gaps in SMR Design

Introduction Gaps in SMR Design Summary

Modeling and Simulation Issues

ESSI: Seismic Body and Surface Waves

I Seismic surface waves carry most seismic energyI SMR bottom: body waves; SMR top: surface wavesI Incoherent seismic motions

Coleman, Whittaker and Jeremic

Gaps in SMR Design

Introduction Gaps in SMR Design Summary

Modeling and Simulation Issues

ESSI: Nonlinear Contact and Soil/Rock Zones

I Seismic energy dissipated at the contactI Seismic energy dissipated within adjacent soil/rock zonesI Passive (complete) structural isolation (beneficial)

Coleman, Whittaker and Jeremic

Gaps in SMR Design

Introduction Gaps in SMR Design Summary

Modeling and Simulation Issues

ESSI: Fluid Structure Interaction

I SMR below water table,I Saturated soil (liquefaction, densification/stiffening)I Buoyant forces (dynamically changing)

Coleman, Whittaker and Jeremic

Gaps in SMR Design

Introduction Gaps in SMR Design Summary

Modeling and Simulation Issues

ESSI: Uncertain Material and Uncertain Loads

I Inherently uncertain material responseI Inherently uncertain (seismic) loadingI Full probabilistic modeling and simulations is desired

Coleman, Whittaker and Jeremic

Gaps in SMR Design

Introduction Gaps in SMR Design Summary

Modeling and Simulation Issues

Modeling Uncertainty

I Goal: reduction of modeling uncertainty

I Modeling Uncertainty: introduced with unnecessarymodeling simplification

I Modeling Uncertainty: introduced with unrealistic modelingsimplification

I Use of results obtained using models with (high) modelinguncertainty for design is questionable

Coleman, Whittaker and Jeremic

Gaps in SMR Design

Introduction Gaps in SMR Design Summary

Modeling and Simulation Issues

Verification and Validation

I Verification provides evidence that the model is solvedcorrectly. Mathematics issue.

I Validation provides evidence that the correct model issolved. Physics issue.

I Prediction: use of computational model to foretell the stateof a physical system under consideration under conditionsfor which the computational model has not been validated.

I Goal: physics based predictive capabilities with lowmodeling uncertainty

I High fidelity, hierarchical, predictive capabilities, aim forhigher modeling sophistication then needed

Coleman, Whittaker and Jeremic

Gaps in SMR Design

Introduction Gaps in SMR Design Summary

Modeling and Simulation Issues

Seismic Isolation

I Goal: reduction of seismic demand

I Active: using engineered devices for SSCs

I Passive: relying on surrounding soil and contact zone

Coleman, Whittaker and Jeremic

Gaps in SMR Design

Introduction Gaps in SMR Design Summary

Modeling and Simulation Issues

Modular, Standardized Design and Construction

For an efficient (safety and economy) SMR:

I High fidelity modeling and simulation of standardizedmodules and a complete SMR

I Design of standardized modules

I Construction of standardized modules that assemble into acomplete, efficient SMR

Coleman, Whittaker and Jeremic

Gaps in SMR Design

Introduction Gaps in SMR Design Summary

Outline

IntroductionOpportunities and Challenges

Gaps in SMR DesignModeling and Simulation Issues

Summary

Coleman, Whittaker and Jeremic

Gaps in SMR Design

Introduction Gaps in SMR Design Summary

Summary

Closing Thoughts

I SMRs present significant opportunities to make investmentin nuclear power more affordable

I Design challenges can be successfully overcome byrelying on high fidelity modeling and simulation

I Use of full nonlinear, time domain, deterministic andprobabilistic modeling and simulation methods/tools (forexample: NRC ESSI Simulator) can help emphasize manybenefits SMR soil-structure system feature!

I Standardized, modular approach to modeling, design andconstruction of SMRs for enhanced safety and economy

Coleman, Whittaker and Jeremic

Gaps in SMR Design