MHI Developmentof Advanced Reactors
26, Jan, 2024

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MHI Road map to achieve Carbon Neutrality
MHI‘s roadmap is set for short, mid and long term to contribute to carbon neutrality.
For short term, top priority is to recover the public trust on nuclear energy lost by
Fukushima incident. MHI supports restart and safety enhancement for existing plants.
For mid term, MHI is developing an advanced light water reactor “SRZ-1200” (Nextgeneration PWR).
For long term, MHI develops several advanced reactors such as SMR to meet diverse
social needs in the future and continue to work on fusion reactor as “permanent energysource”.
Existing LWR

shortterm

Restart existing PWR/BWR
Establish fuel cyclehydrogen production

Next Gen
LWR

Next Generation LWR

midterm

Advanced
Reactors

R&D/Design

longterm

FusionReactorITER program

SMR, High Temperature Gas Reactor,
Fast Reactor, Micro Reactor
Japan’s prototype
Reactor

HTGR

Commercialize(©ITER Organization, http://www.iter.org/)

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2030

2040

2050

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(1) Line-up of MHI’s advanced reactors
In addition to Advanced LWR “SRZ-1200” , MHI promotes development of advanced
new reactors (Small LWR, High-Temperature Gas Reactor, Fast Reactor and MicroReactor) to meet future social needs.
Advanced LWR “SRZ-1200”

Small LWR (SMR)

Power source for existing grids (1,200MWe)
Achieves world’s highest-level safety with innovated technologies,
aiming the commercialization in the mid 2030s

Distributed power source for small grids (300MWe)
Full-passive safety system, initegrated reactor incorporating main
components of the primary system into the vessel
steamgenerator

Radioactive material
release prevention system

coreCore catcher

High-Temperature Gas Reactor (HTGR)Fast Reactor

Micro Reactor

Large-scale & stable hydrogen production
using high temperature heat (over 900°C)
Contributes to the decarbonization inindustrial sector (steel industry, etc.)

Realization of a closed nuclear fuel cycle,
leading to the effective use of resources,
reduction in volume and toxicity of highlevel radioactive waste

Muti purpose portable reactor (forremote island, disaster affected area,etc.)
Full solid reactor core (MHI originaldesign)

Hydrogen production system

HTGR

Heat supply byhigh temperature helium gas© MITSUBISHI HEAVY INDUSTRIES, LTD. All Rights Reserved.

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※This figure includes an outcome of R&D program entrusted by METI.

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(2) Development of advanced LWR “SRZ-1200”
MHI is developing advanced LWR “SRZ-1200” with innovative technologies, which
achieves world’s highest-level safety. Commercialization target in the mid 2030s.
New plant construction is essential to sustain industrial infrastructure and workforce.
Also developing small LWR to meet future social needs, leveraging the technologies
obtained through development of SRZ-1200.
~2020

2030

2040

2050~

Current safety standard
New Standard for SMR“SRZ-1200”

1,200MWe class• Achieves enhanced safety
and competitiveness basedon proven technologies• Limit radioactive effectinside of plant site even inaccident.

Distributedpower source

Small LWR (SMR)• Reduce BoQ by integrating main
components into reactor vessel
300MWe class© MITSUBISHI HEAVY INDUSTRIES, LTD. All Rights Reserved.

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Supreme Safety• Highly resistant to earthquakes,tsunami and acts of terrorism act, etc.
• Confine radioactive materials and limit
its effects within the plant site.

Environmentally Friendly• Zero CO2 emission, and flexible operationin coexistence with renewable energy.

Large scale andstable supply of energy• Large and stable power supply unaffectedby international situation and weatherchange.
“SRZ” represents;
S: Supreme Safety, Sustainability
R: Resilient light water Reactor
Z: Ultimate type (Z) contributing to society by Zero
carbon emission.
4(In Japan, “Z” also has a meaning of “ultimate type”)
4(3) Development of small LWR (1/4)
Main features of MHI SMR
Integrated reactor with natural circulation cooling, eliminating potential of LOCA
Passive safety system without additional power source and water
Built in underground to be resistant airplane crash and natural disasters
ConventionalPWR

MHI
SMR

Control Rod
Drive Mechanism

Reactor building embedded
underground➡ Resistant to airplane crash

SteamGenerator(SG)Steam Generator
Pressurizer

Passive safety system➡ Long term cooling without additional
power source/water

CVReactor Vessel

Reactor Coolant Pump

Integrated Reactor(eliminates main coolant piping/pump)NaturalcirculationcoolingsteamwaterCore➡ Elimination of accident possibility**such as LOCA (Loss of Coolant Accident)© MITSUBISHI HEAVY INDUSTRIES, LTD. All Rights Reserved.

Core cooling by SG

CV/core cooling5(3) Development of small LWR (2/4)
Integrated Reactor
MHI SMR integrates main components of the primary system (steamgenerator, primary coolant pump, pressurizes, etc.) into the reactor vessel.
The concept eliminates the risk of loss-of-coolant accidents caused by theruptures in the primary coolant piping.
Essential Prevention
Integrated Small Reactor（MCP Removal）
Eliminates LOCA

Pressurizer
Steam generator

SG(inside RV)

Control Rod Drive Mechanism

Utilizing two phase flow
（RCP Removal）
Eliminates Seal LOCA
Main Coolant Pipe

Reactor Coolant Pump
Reactor Vessel© Mitsubishi Heavy Industries, Ltd. All Rights Reserved.

RV6

(3) Development of small LWR (3/4)
Passive safety system
Two passive cooling systems provide the plant safety in accidental conditions
without additional power source and water.
The passive system with SG removes core heat by secondary coolant natural
circulation through designated heat exchanger outside of the containment
The passive core/containment(CV) cooling system transfers core heat outsidecontainment.
Passive core cooling system with SG

Passive core/containment cooling
Inner-CVcoolingwater

Hot steam line
Heat removal in closed loop

Water is evaporated outside
CV to atmosphere
Outer-CVcoolingwater

Main Steam line
Cool water line
Feed Water line

© Mitsubishi Heavy Industries, Ltd. All Rights Reserved.

Water is evaporated incore, condensed andremained inside CVCorecoolingwater7

(3) Development of small LWR (4/4)
Built in underground“Built in underground” concept provides safety measures against external
hazards including natural disasters such as earthquakes (high seismic inJapan), tornadoes, as well as terrorism and intentional airplane crash.
MHI SMR’s downsized containment vessel is suitable for this concept.

・Mitigate high seismic response
due to embedment effect・Tornado and APC Protection
by fully Underground location© Mitsubishi Heavy Industries, Ltd. All Rights Reserved.

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(4) Development of High Temperature Gas-cooled Reactor (HTGR)
Decarbonization in not only the energy sector, but in sectors with high CO2 emission such as
the steel industry, chemical and transportation is essential to achieve carbon neutrality by 2050.
HTGR can provide carbon-free high temperature heat (over 900°C*1) which can be used
as a large and stable source for hydrogen production, contributing to decarbonization in
the steel industry and other industries.
*1 HTTR achieved the world’s highest heat temperature (950°C).
MHI Contributions

Hydrogen utilization (e.g.steel industry)

HTGR

Hydrogen production

Hydrogen reduction ironmaking• CO2-free heat supplyof high-temperature(over 900°C)• Steam Methane Reforming method↓ Future• CO2-free hydrogen production• Replacement of cokes (C) in blast furnace with hydrogen• Stepwise increase in added hydrogen ratio to reduce CO2• Final target is 100% hydrogen reduction in the future

HeatHTGR

HydrogenHydrogenproduction system

Blast furnace(conventional)

OCO(Coke)

Fe O

Iron oreC

Hydrogen Reduction
Steel makingHHHydrogen

H2Fe OWaterHeat supply byhigh temperature
helium gas© MITSUBISHI HEAVY INDUSTRIES, LTD. All Rights Reserved.

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Fe IronOCO

O CO2FeHH99(5) Development of fast reactor
Fast reactor utilizes fast neutron which contributes to effective use of resources and reduction ofvolume/radiotoxicity of high-level radioactive waste(HLW).
MHI group, as a prime company of fast reactor development in Japan, is participating in Japanese
government program, international program (Japan-France / Japan-US), and takes lead of development offast reactor with the goal of operation start by 2050 in Japan.
The fast reactor development WG has resumed in Japan, and a sodium-cooled reactor has been
selected as the most promising. Then MHI has been selected as a prime company for demonstration
reactor development. The conceptual design effort will start in 2024.

<Development Schedule>〜2020
Fast Reactor
Development

2025

2030〜

1

F/S
Conceptual Design

1/7

Demo plant
operation
Design/Construction

NEXIP

Volume/Radioactivity
reduction of HLW

Once-thru
直接処分

Volume reduction

F/S ofInnovative FR

100k yrInternationalprogram

WithFR
高速炉300 yr

JP-FRJP-US© MITSUBISHI HEAVY INDUSTRIES, LTD. All Rights Reserved.

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Conceptual diagramOnce-thru
直接処分

WithFR
高速炉Radioactivity reduction*
1010*years needed to radioactivity equivalent to natural uranium

(6) Development of micro reactor (1/2)
Portable reactor for multi-purpose (energy security (storage), energy source for remoteisland and disaster area etc.).
Reactor core has a long service life and requires minimum operation and maintenancethroughout its life expectancy
Solid core by utilizing high heat conduction material (avoidance of leakage incident)[Main Specifications of Micro-reactor]

Remote island© MITSUBISHI HEAVY INDUSTRIES, LTD. All Rights Reserved.

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Core size

Diameter: 1 m or less
Length: 2 m or lessPrimary coolingsystemHeat transfer by high thermal
conductive materials

Output1MWt~/0.3MWe~

Operating cycle

5 years or more

Design life

25

Isolated area

Disaster area
1111

(6) Development of micro reactor (2/2)
The thermal output exceeds 1MWt per module and total power demand is satisfied flexibly
combining multiple units.
Based on “all-solid-state core” concept, the reactor uses a highly thermal conductive
graphite-based material that remove heat from core without liquid coolant.
Transport inside 40ft standard cargo container by conventional transport systems.
Conceptual Specifications of the Microreactor
Item

Value

Fuel

HALEU

Core structure

Layer structure with Graphite typematerial (lighter weight)

Thermal Output

1MWt –

Electric Output

0.3MWe –Operation/Control

Automated

Safety System

Full passiveSize

Inside Standard 40ft freightcontainer© MITSUBISHI HEAVY INDUSTRIES, LTD. All Rights Reserved.

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(7) Development of Fusion Reactor
From a long-term perspective, MHI promotes the development of fusion energy throughthe international collaboration.
MHI will actively support the ITER project*1 based on MHI’s high-level detailed design andmanufacturing technology for the first plasma operation scheduled around 2025.
In addition, MHI continues to advance the development of a fusion demonstration reactor.
*1: International megaproject for the world's largest fusion experiment by seven parties (Japan, EU, US, Russia, China, South Korea and India)

Contract for six
units of the outervertical target

Plasma Heating System
Divertor (Outer Vertical Target)(©ITER Organization, http://www.iter.org/)

The world’s firstcompletion

Toroidal Field Coil© MITSUBISHI HEAVY INDUSTRIES, LTD. All Rights Reserved.

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