Small Modular Reactors(SMRs) for Net Zero
 Nuclear small modular reactors (SMRs) are expected to have an essential and increasingly
important role to play in supporting net zero targets, particularly for hard-to-abate
industrial sectors.
 There are a number of potential benefits to SMRs, ranging from enhanced and passive
safety systems to more attractive financing options due to reduced construction schedules,
fewer components and smaller plant footprints.
 The first SMRs are expected to be built this decade, followed by accelerated deployment
around the world in the 2030s.

NE A

SMRs are reinventing nuclear energy
Small
SMRs are smaller, both in terms of power output and physical size, than conventional gigawatt-scale nuclear
reactors. SMRs are nuclear reactors with power output typically less than 300 megawatts electric (MWe), withsome as small as 1-10 MWe.

Modular
SMRs are designed for modular manufacturing, factory production, portability and scalable deployment.

Reactor
SMRs use nuclear fission reactions to create heat that can be used directly, or to generate electricity. Some SMRs
are based on currently deployed technologies, while others are based on so-called “Generation IV” and advanced
reactor concepts.

As a class of reactors, SMRs are defined by their smaller size, but there is considerable variety within this class of reactors;
they vary by power output, temperature output, technology and fuel cycle. A number of SMRs are based on existing
commercially deployed light water technologies, while others are based on advanced design concepts, offering a range ofsizes – from 1 MWe to over 300 MWe – and a range of temperatures – from 285°C to more than 850°C to meet the specificenergy needs of hard-to-abate industrial sectors.

2

Figure 1. SMRs – ranges of sizes and temperatures for heat applications
1 600

Steel, glass, ceramics, cement

1 400

Water-cooled
Gas-cooled
Fast spectrum
Molten salt
Micro

1 200

Outputtemperature
(℃)

DF300
GTHTR300

1 000

HTTR

Aluminum, steam methane reforming

BANR SMR

800

eVinci
Energy Well
MMR
HermesKaleidos
U-Battery
600

Jimmy

4S
Aurora400

CAREM

HTR-PM
TMSR-500

Xe-100CMSR

IMSR

Chemical Industry,
ammonia refinery

SSR-W
ARC-100

SEALER-55
ACPR50S

KLT-40S RITM-200N
200
TEPLATORNatrium

BREST-OD-300

Westinghouse LFR

Soda ash

SMART

VOYGR

PWR-20LFR AS 200

ACP100NUWARD

BWRX-300

RITM-200M
RITM-200S

Rolls-Royce SMR

Paper

HAPPY20000NEA (2023a, 2023b).

200

400

600

800

1 000

1 200

1 400

Power output (MWth)3

The role of SMRs in pathways to net zero
In 2018, the IPCC considered 90 pathways for emission reductions sufficient to limit average global warming to lessthan 1.5°C (IPCC, 2018). The IPCC found that, on average, these pathways require nuclear energy capacity to increase to
1 160 gigawatts by 2050, from 394 gigawatts in 2020 (IPCC, 2018).
This is ambitious for nuclear energy, but not beyond reach. As illustrated in Figure 2, analysis by the Nuclear Energy Agency(NEA, 2022) finds that this level of capacity can be achieved through a combination of the long-term operation of existing
plants, large-scale Generation III new builds and rapid deployment of SMRs. Assuming an SMR build rate that reaches
75 gigawatts per year by 2050, up to 375 gigawatts of installed capacity would be built over the next three decades.
Significant demand for SMRs is expected in hard-to-abate sectors, including for on-grid power to replace coal power plants;
off-grid heat and power to replace diesel generators for remote mining operations; high-temperature heat to replace fossil
fuel cogeneration in heavy industries such as chemicals processing; and marine propulsion to replace heavy-fuel oil formerchant shipping.

Projected contributions of nuclear energy
to cumulative emissions reductions (2020-2050)…electricity…heat…hydrogenTotals…long-term operation

38.3

6.7

4.3

49.2

…new builds of large Generation III reactors

16.2

4.2

2.4

22.8

…small modular reactors (SMRs)

9.7

3.6

1.8

15.1

Totals

64.1

14.5

8.5

87.1

Cumulative emissions* avoided from…

* All cumulative emissions from 2020 to 2050 are shown in gigatonnes of carbon dioxide (GtCO2).

4

Figure 2. Full potential of nuclear contributions to net-zero

90

Installed capacity (GWe)

1 200

80
70

1 000

60
800

50
40

600

30

400

20
200

10
0
2020

2025

2030

2035

2040

2045

Cumulative CO2 emissions avoided (GtCO2)

100
1 400

2050

Cumulative emissions avoided
IPCC 1.5°C scenarios (2050 average) = 1 160 GW nuclear capacity (based on the average of IPCC 1.5°C scenarios)
Conservative projections
Small modular reactors (2035 market outlook)
Large-scale new builds (under construction)
Long-term operation (planned)

Ambitious projections
Small modular reactors (post-2035 market extrapolation)
Large-scale new builds (planned)Long-term operation (to 80 years)

Source: NEA (2022).

5

Box 1: Powering past coal with SMRs
Coal power is still the largest source of electricity generation and emissions globally. However, the coal fleet inOECD countries is slated for retirement due to ageing assets, accelerated decarbonisation policies and dwindlingcompetitiveness. Momentum is growing globally to transition a portion of the global coal fleet to nuclear power,with commitments from utilities in the United States and Central Europe. This presents a significant short-term
market opportunity for deploying SMRs in support of climate action.
Due to their size and flexible deployment attributes, SMRs are well-suited to replace coal power plants, many ofwhich have capacities below 500 MWe. Compared to alternatives, SMRs stand out for their dispatchability, energy
density and ability to reuse existing infrastructure.
Capital costs will be the primary driver of SMR competitiveness. Beyond serial deployment, cost reductions are
possible by reusing existing coal infrastructure. Meanwhile, increasing fuel costs, carbon pricing and stricter
environmental regulations are improving the relative competitiveness of SMRs over fossil fuel alternatives.
Additionally, SMRs can be part of a diversified technology portfolio that uses nuclear power and renewables tominimise cost and mitigate grid reliability risks. Coal-to-nuclear transitions also bring social benefits and support ajust transition for local communities, offering opportunities to retrain and retain the existing coal workforce and tobring additional high-pay jobs during both construction and operation.
The short-term market potential is significant, with around 380 GW of potential market by 2040, mainly driven byretirements in the United States, Europe and Korea. The United States alone represents around 70% of this market.
There are no major technical barriers to replacing coal with SMRs. Utilities should focus on securing water withdrawal
and grid transmission permits to maximise site benefits. Siting constraints must be met, particularly regarding
seismic conditions, population density and proximity to external hazards. Potential regulatory challenges and legacy
coal ash issues can be overcome with proactive planning and investment.
A few large nuclear utilities own over 100 GW of coal capacity globally and could lead as first movers, taking advantage
of fleet effects to reduce costs and risks. Establishing industrial consortia among these utilities could further improvethe economics and help to enable competitive SMR deployment. Non-traditional players are entering the market as
potential off-takers while partnering with vendors and utilities for SMR construction and operation.

6

Figure 3. Coal replacement with SMR global market potential by 2040 (in GWe)

Source: NEA (forthcoming).
Note: These estimates have been derived using data from the Global Plant Tracker Database.

7

Box 2: Replacing diesel with SMRs for remote mining – Including criticalminerals for the clean energy transition
Mining is a strategic sector in OECD countries to secure domestic supply chain capabilities, support economic
growth in rural communities, and enable the clean energy transition. The mining sector represents 2-3% of global
CO2 equivalent emissions, and demand for mining is expected to increase sharply.
Mining companies are exploring the use of SMRs to support the decarbonisation of their activities. In the UnitedStates, SMRs are being considered for large grid-connected mines at brownfield sites to support both mining
and mineral processing activities. In Poland, efforts are moving forward to deploy SMRs for copper mining andprocessing.
Off-grid mining offers the most promising near-term opportunities to decarbonise global mining with SMRs due tothe high costs associated with operating in remote areas where the current source of energy is diesel generators. In
addition, off-grid mines have an average installed power capacity of 16 MWe, suitable for very small SMRs.
The NEA estimates that the market for SMRs for brownfield remote mining could reach more than 2 GWe, primarily
concentrated in Australia, Canada, Chile, Indonesia, Russia, the United States and within Sub-Saharan Africa.
NEA analysis projects a growing need for remote mining due to increased demand for critical minerals, which areessential to technologies that are required for the clean energy transition. The NEA has found that 16% of criticalmineral deposits globally are located more than 20 kilometres from an electricity grid, and that certain specificcritical minerals - such as rare earth elements including germanium and niobium - are more commonly found inthese remote areas.
In addition to brownfield remote mines, market potential exists for greenfield mines, with about 15% of global
mining deposits suitable for remote operations.
To effectively integrate SMRs into mining operations, policy support measures will be needed to enhance regulatory
efficiency. Standardisation across jurisdictions may streamline the licensing process and simplify operational
aspects. Transportable SMRs will offer further flexibility.

8Figure 4. Existing remote mines that could be replaced by SMRs (total = 2 GWe)

Note:China’s mining
facilities are underrepresented in the data
set. Excluding China,
the global coverage ofthe data set is 82%.
This method does notaccurately capture some
self-generating mines(e.g. in Sub-SaharanAfrica).
Source: NEA(forthcoming).

Figure 5. Percentage of critical mineral deposits further than 20 kms from the nearest electricity
Niobium and Tantalum
Germanium
Molybdenum
Tin
CobaltTitanium
Boron
GalliumTungsten
Silicon
PGMs
Magnesium
SilverCadmium

Remotedeposits
Grid-adjacentdeposits

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

9

SMRs’ market readiness
Innovation in SMRs is accelerating across the globe.
On the technologies side, several innovative nuclear concepts are under development and nearing commercialisation anddeployment. Some are based on traditional light water reactor concepts while others are Generation IV concepts, manyof which use new coolants and moderators. Various reactor configurations are also envisaged, with both land-based andmarine-based approaches proposed, as well as mobile and multi-module configurations.
On the demand side, markets are signalling the need for innovative technologies to address energy and climate challenges –including in hard-to-abate industrial sectors. A key market around the world for SMRs and Generation IV reactors is on-grid
to replace coal power generation. Beyond on-grid power generation, however, several other markets are signalling interestin SMRs and Generation IV reactors: off-grid heat and power to replace diesel generators in remote regions, including formining operations; high temperature heat to replace fossil cogeneration in heavy industries such as chemicals processing;and marine propulsion to replace bunker fuel for merchant shipping.
These markets represent emerging – and often disruptive – applications of nuclear energy technologies. Near-term policy
and investment decisions will play a key role in shaping overall market outcomes. Public policy and private sector decision
makers alike are looking for authoritative assessments of SMRs’ power needs, temperature ranges and other operational
and technical requirements for specific applications to be able to understand and map market demand.
Beyond technical feasibility, there are several enabling conditions for success to connect supply and demand. Technologies
must be a good fit to connect with the specific market applications. Governments and international organisations havea role to play in creating the enabling frameworks – including policies, regulatory readiness and legal aspects. Safe andsecure SMR fuel supply chains are essential, as is a responsible plan for the management of the back-end of the fuel cycle.
Supply chains more broadly, infrastructure and human resources are all essential enablers. Equally importantly, production
costs must be competitive and a mix of public and private financing is required to enable demonstration and deployment of
nuclear innovation.
With the right enabling frameworks and public-private partnerships, initial deployment of demonstration reactors is
expected this decade, with accelerated deployment around the world to follow in the 2030s.

10Figure 6. SMRs under development around the world

NEA (2023a, 2023b).

11

Figure 7. SMR siting announcements and progress

40
1 ARC-100
ARC Clean Technology
2 CAREM
CNEA
3 ACPR50S
CGN
4 ACP100
CNNC and NPIC
5 NUWARD
nuward EDF GROUP
6 BWRX-300
GE-Hitachi Nuclear Energy
7 Hermes
Kairos Power
8 SEALER-55
Leadcold Reactors
9 SSR-Wasteburner Moltex Energy
10 VOYGR
NuScale Power
11 Aurora
OKLO
12 Rolls-Royce SMR Rolls-Royce SMR Ltd.
13 KLT-40S
Rosatom
14 RITM-200N
Rosatom
15 RITM-200S
Rosatom
16 Natrium
TerraPower
17 HTR-PM
INET
18 MMR
Ultra Safe Nuclear
19 U-Battery
Urenco20 eVinci
Westinghouse ElectricCompany
21 Xe-100
X-energy
NEA (2023a, 2023b).

12

18
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40

BANR SMR
BWX Technologies
Project Pele
BWX30Technologies
20
19 18
11
Energy Well 21CVŘ
6
1
6
DF300
Dual10
Fluid Energy
1
21
18
38
38
SMR-160
HoltecInternational
21 9
16
34 23
GTHTR300
JAEA
18
20 26
HTTR
JAEA
7 6
Jimmy
Jimmy Energy
SMART
KAERI
PWR-20Last Energy
LFR AS 200
newcleo
BREST-OD-300 NIKIET
Kaleidos
Radiant
RITM-200M
Rosatom
CMSR
Seaborg Technologies
HAPPY200
SPIC
IMSR
Terrestrial Energy
TMSR-500
ThorCon International
4S
Toshiba Energy Systems &Solutions Corporation
41 Westinghouse Westinghouse Electric
LFR
Company
42 TEPLATOR
ZČU and CIIRC CTU

12
12

12

31
5

2

Non-binding
Site owner has
agreements/MOUs/ shortlisted thenon-binding
technology
announcements

14

8

5

26 31

12

6
33

26
31 10

30

Site owner has Received permit(s) Construction has
selected theand/or licence(s) started on the site
technology
for construction on
the site

15

13

1 ARC-100
ARC Clean Technology
2 CAREM
CNEA
3 ACPR50S
CGN
4 ACP100
CNNC and NPIC
5 NUWARD3
37 nuward EDF GROUP
6 BWRX-300
GE-Hitachi Nuclear Energy
7 Hermes
Kairos Power
1728
8 SEALER-55 4
Leadcold Reactors
9 SSR-Wasteburner
Moltex Energy
44
10 VOYGR
NuScale Power
11 Aurora
OKLO
4 33512 Rolls-Royce SMR
35 Rolls-Royce SMR Ltd.
13 KLT-40S
Rosatom
14 RITM-200N
Rosatom
15 RITM-200S
Rosatom
16 Natrium
TerraPower
17 HTR-PM
INET
18 MMR
Ultra Safe Nuclear
19 U-Battery
Urenco20 eVinci
Westinghouse ElectricCompany
21 Xe-100
X-energy

22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40

BANR SMR
Project Pele
Energy Well
DF300
SMR-160
GTHTR300
HTTR
Jimmy
SMART
PWR-20LFR AS 200
BREST-OD-300
Kaleidos
RITM-200M
CMSR
HAPPY200IMSR
TMSR-500
4S

41 Westinghouse
LFR
42 TEPLATORBWX Technologies
BWX Technologies
CVŘ
Dual Fluid Energy
Holtec International
JAEA
JAEA
Jimmy Energy
KAERI
Last Energy
newcleo
NIKIET
Radiant
Rosatom
Seaborg Technologies
SPIC
Terrestrial Energy
ThorCon International
Toshiba Energy Systems &Solutions Corporation
Westinghouse ElectricCompanyZČU and CIIRC CTU

13

“Accelerating SMRs for Net Zero”: A new NEA initiative
The NEA is launching of the “Accelerating SMRs for Net Zero” initiative at COP28.
The “Accelerating SMRs for Net Zero” initiative capitalises on the NEA’s extensive network of industry leaders, government
officials and experts. This initiative aims to conduct authoritative analyses and support collaborative actions, enabling
interested decision makers to unlock the full potential of SMRs for climate action. The focus is on establishing practical,
solutions-oriented activities supported by a comprehensive plan of collaboration and knowledge exchange. The goal is toinform policy and investment decisions by governments, industry players and the financial sector.
Priorities for 2024 include:Market opportunities: Producing authoritative assessments of SMR power requirements, temperature ranges andoperational specifications to meet decision-making criteria and timelines.



Legal, logistical and regulatory challenges: Addressing issues related to the mobility and transportability of SMRs.

Technological and market challenges: Tackling obstacles associated with sector coupling.



Demand signal for fuel cycle investments: Identifying the need to finance the production of high-assay low-enricheduranium (HALEU) in volumes significant enough to meet a 2027 timeline for first movers.

The NEA anticipates that key findings in these areas and others will be presented and discussed during the inaugural “SMRsfor Net Zero” Summit in September 2024.
For more information about the “Accelerating SMRs for Net Zero” initiative, please e-mail: SMR4NZ@oecd-nea.org.

14

References and further reading
NEA (forthcoming), NEA SMR Industrial Case Studies, OECD Publishing, Paris.
NEA (2023a), The NEA SMR Dashboard, OECD Publishing, Paris, www.oecd-nea.org/smr-dashboard.
NEA (2023b), The NEA SMR Dashboard: Volume 2, OECD Publishing, Paris, www.oecd-nea.org/smr-dashboard-ii.
NEA (2022), Meeting Climate Change Targets: Projecting the Potential Role of Nuclear Energy, OECD Publishing, Paris, www.
oecd-nea.org/nea-7628.
NEA (2021), Small Modular Reactors: Challenges and Opportunities, OECD Publishing, Paris, www.oecd-nea.org/smr21.

15

OECD Nuclear Energy Agency (NEA)
46, quai Alphonse Le Gallo
92100 Boulogne-Billancourt, France
Tel.: +33 (0)1 73 21 28 19
nea@oecd-nea.org www.oecd-nea.org
Cover page: Romolo Tavani/Shutterstock.

OECD/NEA, November 2023