Rochau Consortium for Integrating Energy Systems in Engineering and Science Education (CIESESE) presentation

1. 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.sandia.gov
SNL Small Modular Reactor Program
Gary E. Rochau, Advanced Nuclear Concepts
gerocha@sandia.gov 505-845-7543

2. First Generation US Small Modular Reactors
2
• 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

3. 3
• Add MELCOR models to address
unique NuScale SMR:
o Geometry,
o Heat transfer
o Aerosol behavior
o 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-Generationof Electricity and
Water”, D. T. Ingersoll et al., Desalination,
Vol. 340,p. 84-93,2014.

4. NuScale SFP Modeling
4
• 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

5. Generic SMR Containment
5
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
removalfrom
containment
atmospheres due to
higher deposition
surface
area/containment
volume, and particle
removalby high
steam concentration
gradients to cooled
walls.

6. Surtsey Facility: Large Sealed Pressure Vessel for
Studying Containment Atmospheric Processes
6
• 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

7. 7
Energy Security for DoD Installations

8. SMRs – Case Study Site Layouts and Meeting
AFSPC Mission Critical Needs
8
§ RFI responses received from
B&W mPower, Holtec,
NuScale, Westinghouse
§ All state they can meet
Mission Critical needs
§ Low power operations - <5 MWe
§ Black start
§ Island mode
§ Operation without offsite AC
power
§ May require license exemptions,
amendments or other NRC
approvals

9. Unsubsidized Cost of Nuclear Power
§ Most models assume ~ $5,000/kw overnight cost
§ Higher cost of money, combined with income and
property taxes, can make LCOE from an investor-owned
SMR 50% higher than one owned by a municipality
§ LCOE range ~ $65 / MWh to ~ $110 / MWh
§ Average LCOE ~ $85 / MWh

10. The sCO2 Brayton Cycle
10
Compression
work greatly
reduced
𝑐𝑜𝑚𝑝𝑟𝑒𝑠𝑠𝑖𝑜𝑛 𝑎𝑛𝑑 𝑝𝑢𝑚𝑝 𝑤𝑜𝑟𝑘 = ∫ 𝑃𝑑𝑣 + ∫ 𝑣𝑑𝑃
20 meter Steam
Turbine (300 MWe)
(Rankine Cycle)
1 meter sCO2
(300 MWe)
(Brayton Cycle)
Expansion
through
turbine

11. Path to High Efficiency Brayton Cycle
11

12. Technical Challenges
12
§ 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.

13. Direct sCO2 Receiver Configuration
13
Heliostat Field
Direct sCO2
Receiver
Main
Compressor
G
High-T
Recuperator
Low-T
Recuperator
Re-
Compressor
Turbine
Gas
Cooler
~20 MPa, 700 C

14. 14