Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-AC04-94AL85000 SAND2015-8222 PE

energy. sand ia.gov

SNLSmallModularReactorProgramGaryE.Rochau,AdvancedNuclearConcepts

gerocha@sandia.gov 505-845-7543

FirstGenerationUSSmallModularReactors

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• Babcock & Wilcox•mPower•180 MWe

•NuScale Power, Inc.•NuScale•45 MWe

•Westinghouse Nuclear•225 MWe

•Holtec International•160 MWe

•Common Features•Steam Generators inside pressure vessel•Light water moderation•Passively safe•All cores underground

Westinghouse

Holtec

Sandia Support to develop tools for Design Certification Efforts awaiting inquiry from NRC

Westinghouse~200 MWe

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• Add MELCOR models to address unique NuScale SMR:o Geometry,o Heat transfero Aerosol behavioro Spent fuel pool (SFP)

• Geometry: Allow the simultaneous modeling of reactor pressure and containment vessels.

• Heat transfer: o Add new shroud model for heat

transfer from reflectors.o Upgrade condenser model.

• Aerosol behavior: add aerosol resuspension model.

• SFP: quantify accident behavior.

NuScale SMR MELCOR Code Development

NuScale SMRs, Refueling Area, and SFP.

Source: “NuScale Small Modular Reactor for Co-Generation of Electricity and

Water”, D. T. Ingersoll et al., Desalination, Vol. 340, p. 84-93, 2014.

NuScale SFP Modeling

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• Develop MELCOR input models to simulate the behavior of bounding SFP accidents.

• Perform systematic testing of the new models to ensure fidelity and robustness.

• Compare MELCOR simulations with experimental data and known analytical solutions—validation and verification (V&V).o MELCOR output compared

favorably with experimental data and analytical solutions.

MELCOR

GenericSMRContainment

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Data for this process is

currently from 1-inch scale experiments

applied to a 80-ft high vessel. A

scale-up factor of 960!

Supporting EPRI/NEI Off-Site Release Program

Propose to measure enhanced aerosol

removal from containment

atmospheres due to higher deposition

surface area/containment

volume, and particle removal by high

steam concentration gradients to cooled

walls.

SurtseyFacility:LargeSealedPressureVesselforStudyingContainmentAtmosphericProcesses

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• 100 m3 ASME Steel Pressure Vessel

• 1 MPa Working Pressure• Insulated - Prototypic

Steam/Air/H2 Atmosphere• Realistic Scaled Containment

Structures• Removable Upper/Lower Heads• Instrumentation Ports At Six

Levels• High Volume Gas and Steam

Supply Systems• Flexible Data Acquisition and

Control

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Energy Security for DoD Installations

SMRs– CaseStudySiteLayoutsandMeetingAFSPCMissionCriticalNeeds

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§ RFIresponsesreceivedfromB&WmPower,Holtec,NuScale,Westinghouse

§ AllstatetheycanmeetMissionCriticalneeds§ Lowpoweroperations- <5MWe§ Blackstart§ Islandmode§ OperationwithoutoffsiteAC

power§ Mayrequirelicenseexemptions,

amendmentsorotherNRCapprovals

UnsubsidizedCostofNuclearPower

§ Mostmodelsassume~$5,000/kwovernightcost§ Highercostofmoney,combinedwithincomeand

propertytaxes,canmakeLCOEfromaninvestor-ownedSMR50%higherthanoneownedbyamunicipality

§ LCOErange~$65/MWhto~$110/MWh§ AverageLCOE~$85/MWh

The sCO2 Brayton Cycle

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Compression work greatly reduced

𝑐𝑜𝑚𝑝𝑟𝑒𝑠𝑠𝑖𝑜𝑛 𝑎𝑛𝑑𝑝𝑢𝑚𝑝𝑤𝑜𝑟𝑘 = ∫ 𝑃𝑑𝑣 +∫ 𝑣𝑑𝑃

20 meter Steam Turbine (300 MWe)

(Rankine Cycle)

1 meter sCO2(300 MWe)

(Brayton Cycle)Expansion through turbine

Path to High Efficiency Brayton Cycle

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Technical Challenges

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§ Heat source/economic benefits§ Scalability§ Bearings & seals§ Benchmark models with sCO2§ Materials for temperature & pressure

Many components are COTS, But not qualified for sCO2 at high temperature and pressure.

Direct sCO2 Receiver Configuration

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HeliostatField

DirectsCO2Receiver

MainCompressor

G

High-TRecuperator

Low-TRecuperator

Re-Compressor

Turbine

GasCooler

~20 MPa, 700 C

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