Nuclear Reactors with Heat Storage to Boost Revenue and Replace Fossil Fuels Charles Forsberg Massachusetts Institute of Technology Email: [email protected]National University Consortium Workshop Innovations in Advanced Reactor Design, Analysis and Licensing North Caroline State University September 17-18, 2019
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Nuclear Reactors with Heat Storage to Boost Revenue and ......Cerro Dominador Project (under construction, Chile, ~4800 MWh(t)) 13. Pilot Plant Steam Accumulators Sensible Heat (Hot
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Nuclear plant design has followed coal plant design with the
reactor integrated to the power block that includes the turbine
generator. There is an alternative design, the nuclear reactor is in
the security zone with the power block outside the security zone
coupled to gigawatt-hour heat storage systems. Changes in
nuclear plant requirements may make this the preferred option for
future reactors. Electricity markets are changing that creates
incentives for adding heat storage but gigawatt-hour heat storage
systems are very large and couple to the power block. The storage
system size will likely exceed the physical size of the nuclear
power plant and the power block. If the power station includes
heat storage, the reactor is a heat production system that converts
cold salt to hot salt and is effectively decoupled from the
production of electricity or sending heat to industry—avoiding
the complications from directly coupling the reactor and the grid
while boosting grid resiliency. Second, nuclear requirements
(security, construction, licensing, operations, etc.) raise the costs
of anything tightly coupled to the nuclear reactor. With separation
of the reactor from power block, the nuclear reactor has the
nuclear licensing, construction, and security costs. The power
block and heat storage are designed, licensed, built and operated
to normal industrial standards with a clear over-the-fence
separation from the nuclear systems. The workshop is a first look
at this alternative reactor design option that is applicable to
multiple reactor types.
Workshop (Spring 2020):
Separating Nuclear Reactors
from the Power Block with Heat
Storage: A New Power Plant
Design Option
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DayLo
ad
/Ge
ne
rati
on
(M
W) Seasonal
Surplus
Seasonal Deficit
S. Brick -California Case Study: Clean Air Task Force
Greater Challenge in a Low-Carbon World If Electrify
Home Heating and Industry: California Example
Smoothed Daily
CAISO Load (MW)
• Add electric
winter heating
load at worse
time for wind and
solar
• Add flat industrial
load
• No good estimates
of impacts of
heating loads
Smoothed Daily
Renewable
Generation (MW)
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Add Heating Load
Nuclear-Geothermal Heat Storage System
Nuclear Heat to Create Artificial Geothermal Heat Source
Oil Shale
Oil Shale
Hu
nd
red
s o
f M
ete
rsH
un
dre
ds
of
Me
ters
Rock
Permeable
Cap Rock
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Geothermal PlantNuclear Plant
Fluid
Return
Thermal
Input to
Rock
Thermal
Output From
Rock
Fluid
Input
Nesjavellir
Geothermal
power
plant;
Iceland;
120MW(e);
Wikimedia
Commons
(2010)
Conventional
Combined Cycle Gas
Turbine
Nuclear Air-Brayton Combined Cycle (NACC) to
Replace Natural Gas Turbine Combined Cycle
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• Gas Turbine Advantages
– Variable Electricity to
the Grid
– Fast Response
• Nuclear Equivalent
Proposed
– Heat Storage
– Peaking Power
Wind/Solar without Cheap Natural Gas & Gas Turbines is Expensive
• Europe
– No cheap natural gas
– Push for renewables
– Expensive electricity
• If use wind and solar,
require affordable
dispatchable electricity
• Require Hydro
(Northwest) or Cheap
Natural Gas (Great Plains)
NACC With Heat Storage and Thermodynamic Topping Cycle
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NACC Performance Parameters
Turbine
1&2 Exit
Temp
Turbine 3
Nominal
Exit Temp
Turbine 3
Boosted
Inlet
Temp
Base
Efficiency
Fraction
Base from
Steam
Hydrogen
Burn
Efficiency
Combined
Efficiency
Brayton
Gain
Overall
Gain
Sodium Near-Term System (Nominal Inlet Temperature 773 K (500°C)
680.5 K 640.5 K 1100 K 32.8% 18% 71.1% 48.4% 1.464 2.522
680.5 K 640.5 K 1700 K 32.8% 18% 74.2% 60.4% 2.347 5.744
Molten Salt Advanced System (Nominal Inlet Temperature 973 K (700°C)
792.5 K 722.5 K 1100 K 45.5% 24% 74.5% 51.1% 1.168 1.403
792.5 K 722.5 K 1700 K 45.5% 24% 75.0% 61.6% 1.834 3.070
Incremental Combustion
Fuel to Electricity Efficiency
Power Gain: First Case Brayton
Output 46.6% Higher When Peak Mode
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Option to Add Heat Storage Between Brayton Cycle and Heat Recovery Steam Generator
Heat Recuperator
Options
• Traditional Firebrick
• Hot Concrete
• Crushed Rock
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Three Electricity Generating System Options for
a Low-Carbon World that Meet the Three
Requirements:
Electricity Generation
Energy Storage
Assured Peak Generating Capacity
Nuclear Energy with Heat Storage and Backup
Furnace (Biofuels, Hydrogen, etc.)
Heat Generation to Heat Backup Boiler for
Electricity and Storage Storage Depleted Storage
Concentrated Solar Power (CSP) has Same System Design 37
Generation Electricity Backup GT for
Storage Depleted Storage
Wind / Solar PV System With Electricity Storage
and Backup Gas Turbine
McCrary Battery Storage Demonstration
Seasonal Solar & Wind Input Requires Significant
Operation of Gas Turbine Backup (Biofuels and H2) 38
Fossil Plant with Carbon Capture
and Sequestration
• Post combustion
capture CO2
• 240 MW
– Added to Unit 8
(654 MW)
– 37% of Unit 8
emissions
• 90% CO2 capture
Petra Nova (Joint venture): NGR Energy and
JX Nippon Oil and Gas Exploration
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Comparison of the Three Energy Options
Some Mixture Likely Where Choices Depend upon Location
Option/
Characteristic
Nuclear* with
Storage + Fuel
Wind/Solar PV*
With Storage + Fuel
Fossil with Carbon
Sequestration
1. Base-load Fuel cost Low ~0 High
2. GWtotal/GWpeak 1 >2 1
3. Low-carbon fuel
demand (H2, biofuels, etc.)
Low High None
4. Location Dependent No Yes Yes
Numbered Notes below coupled to characteristics
2. GW(e) nameplate rating divided by GW(e) assured peaking capacity. Wind and solar PV total generating capacity equals Wind/Solar PV + battery + gas turbine but if extended low
wind/solar conditions, the only assured capacity is the gas turbine.
3. Low-carbon fuel required for assured peaking capacity when storage is depleted. For nuclear this peaking capacity above base-load nuclear. For wind/solar this is total power because
no assured base-load capability from wind and solar.
4. No location dependency for nuclear. Wind/Solar depend upon local wind and solar conditions. Fossil depend upon sequestration sites.
*Concentrated Solar Power systems have some of the characteristics of nuclear systems and some of the characteristics of solar PV
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• Mismatch between full production and electricity demand implies more
storage and higher costs; Nuclear with storage has the closest match
Lowest Cost System Depends upon (1) System Option Cost