Mitsubishi Activities for FBR
Commercialization Development
NAOTO MOTOOKA*1

HIROYUKI SATO*1

2SHIGERU KUNISHIMA*3

TAKAYA ITO*

The fast breeder reactor (FBR) cycle enabling the effective use of uranium as a semi-permanent resource was selected as an“essential national technology” and has been developed as a national project in which MHI has positively participated. In October,
2006, its proposed sodium-cooled loop-type large-scale FBR was adopted as a principal concept of commercial reactors. In April
2007, MHI was selected as the core company to carry out the development of FBRs on the strength of its past achievements. In
response, MHI established Mitsubishi FBR Systems, Inc. (MFBR) to promote the development of FBRs. As the core company, we aredetermined to continue carrying forward the intensive development of FBRs at an accelerated rate toward the planned start-up of thedemonstration reactor in 2025 to ensure early commercialization of FBRs.

response to the basic policies for FBR development, compiledby the Atomic Energy Commission of Japan,1 the concrete
objectives of the realization of a demonstration reactor (startup of operation) by around 2025 followed by the introductionof FBRs on a commercial basis not later than 2050 3 wassettled. MHI has also positively participated in this national
project from the initial stage as a manufacturer of nuclear
plants and has accumulated and improved related technology
i n t he a reas of desig n, ma nu fact ure a nd i nspect ion,
responding appropriately to the service conditions peculiar
to a sodium-cooled reactor.

1. Introduction
Through the effective utilization of uranium, the FBR
cycle has the potential to generate ten times the energy ofother energy sources (Fig. 1) and is expected to be a semipermanent resource.1 In addition, CO 2 production can bereduced down to approx. 1/100 th that of fossil fuels, greatlycontributing to the measures against global warming. Up tothe present, the FBR research and development have been
conducted as a national project centered on the Japan Atomic
Energy Agency (JAEA), and in March, 2006, the technology
was selected as an Essential National Technology 2 by theCouncil for Science and Technology Policy, stating that the“FBR cycle technology that can greatly contribute to thestable supply of energy for the nation to the benefit of its
industrial development as well as improvements in peoples'
lives, and, accordingly its development will need largescale and long-term support by the state.” Furthermore, inAmount of energy (Gtoe)

10000

1000

2. MHI activities for FBR development
The development of FBRs in Japan has been conductedin a staged manner including the experimental fast reactor“Joyo” and the protot ype fast breeder reactor “Monju”.
A plant verification test is underway at “Monju” towardt he rest a r t of operat ions. M H I has t a ken pa r t i n t heupgrade work for the “Joyo” MK-III project (improvementof secondary equipment in relation to power upgrading)and the improvement of “Monju” to prevent sodium leaks,in addition to the commitment to the plant engineering,
design, manufacture and on-site work for the maintenanceand replacement of these main components, and thus has
significantly enhanced not only the overall plant technology
related to the design, manufacture and on-site work but also
the maintenance and repair technology associated with thesodium-related components and piping systems.
In addition, MHI has participated in the design anddevelopment of the technolog y for the demonst rat ion
reactor promoted by electric utilities as a reactor to succeed“Monju”. MHI also took part in the Feasibility Study on
Commercialized Fast Reactor Cycle Systems (FS) (from 2001

(Converted based on proved reserves）

Plutonium utilization
in LWRs (Pluthermal)

100

10Oil

NaturalGas

LWR

Coal

FBR

Fig. 1 Potential Productivity of Principal Energy Sources*1 Nuclear Energy Systems Headquarters*2 Mitsubishi FBR Systems, Inc.
*3 Mitsubishi Nuclear Energy Systems Inc.

Mitsubishi Heavy Industries, Ltd.
Technical Review Vol. 45 No. 1 (Mar. 2008)56

to 2005) implemented by power utilities, and manufacturers,
under the leadership of JAEA for the purpose of presenting
both the concept of an economically competitive reactor
and the R&D process to attain the desired result, and thus
validated the concept through element tests and conceptual
design study.4 As a result, the concept proposed by MHI was
designated as the reactor to be primarily developed (principalconcept) in October, 2006. 5
At the start of the FBR Cycle R&D Project, the Government
decided a policy to concentrate the responsibilities andengineering functions to a sole core company, so that FBRdevelopment activities could be effectively carried out undera clear chain of responsibility to promote the development of
the principal concept, and in February, 2007, JAEA called for
applications for a core company to engage in the engineering
activities for Fast Breeder Reactor development,6 for which
MHI applied and was successf ully awarded in April ofthe same year.7 Further MHI established Mitsubishi FBRSystems, Inc. (MFBR) and has been committed to promoting
the study and R&D of the conceptual design of commercial
and demonstration FBRs in cooperation with JAEA.

Increased scale
2 loops(1,500 MWe × 2, twin plant) (reduced number of loops)
Steam generator
with double-walled
heat transfer tubes

High-strength
high-chromium steel
Decay heatremoval system
based on complete
natural circulation

Specifications:• Electric output:
1,500 MWe• 2 loops (1 turbine)• Reactor outlet/
inlet temperature:
550°C/395°C• Mixed oxide (MOX) fuel• Power generating
efficiency:42.5%
Integrated IHX
with primary pump

Large-diameterprimary piping(reducedpiping length)More compact
reactor vessel

Recriticality avoidance basedon inner-duct concept

Fig. 2 Sodium-Cooled Loop Type Large-Scale FBR4

shortening the piping length by connection of outlet/inlet
piping to the upper part of the reactor vessel, as well as theintegration of a pump into IHX (integrated IHX with primarypump) (Fig. 2), thereby demonstrating the concept has
significant potential for economy. 4,5

3. Outline of Sodium-Cooled Loop Type Large-ScaleFBR Plant

4. Conceptual road map toward a commercial FBRSince a commercial FBR is required to have economicefficiency equivalent to a conventional LWR, MHI proposed
the innovative concept of a sodium-cooled loop type largescale reactor in which innovative technology is incorporated
for enhanced safety and reliability besides being economical(Fig. 2). The present concept aims not only to increase theoutput power but also to reduce the amount of construction
materials as much as possible through the reduction in thenumber of loops, the adoption of high-chromium steel withlow expansion coefficient and high-temperature strength,In order to introduce commercially-based FBRs by 2050,
the construction of a demonstration reactor is indispensable
to implement step by step development based on the element
study and simulation tests on an engineering scale in parallelwith the design tasks. To address this construction project,
MHI believes it necessary to adopt a two-stage development
strategy, i.e. the Development Test Reactor to demonstrate
the concept of a commercial reactor with leading innovativetechnology (500-600 MWe: to be operated by about 2025)

1500
Commercial FBR(-1,500 MWe)• Validation of scale-up• Demonstration of economics

Electric power (MWe)1000• Demonstration of innovative technologies• Confirmation of economics perspective

500300Introductory commercial FBR(750-1,000 MWe)

Development test FBR(500-600 MWe)
R&D
• Demonstration
for commercializationof FBR applicability• Irradiation test Prototype FBR “MONJU”(280 MWe)
Experimental FR“JOYO”• Demonstration of power generation(140 MWt)• Demonstration of breeding performance• Establishment of sodium handling technology
2020
Year2050

Fig. 3 Conceptual Road Map for the Development of Commercial FBR8

Mitsubishi Heavy Industries, Ltd.
Technical Review Vol. 45 No. 1 (Mar. 2008)57

followed by the Introductory Commercial Reactor to validate
the increased scale and achievement objectives (economicefficiency including cycle incidents) (750 -1,000 MWe: tobe operated in about 2035) (Fig. 3). 8 Incidentally, it willbe essential to be prepared for long-term maintenanceand handing down technical competence along with thecultivation of human resources toward the production ofFBRs around 2050, and therefore, the present two-step
strategy is a meaningful methodology for development.

selected as a principal concept of commercial FBR on thebasis of this technology, and in 2007 was selected as the corecompany to engage in engineering activities for fast breeder
reactor development by the government. Furthermore, MHI
has established a new company MFBR to push forward thisproject.
To promote FBR development, it is essential to establish
the basic specifications for the demonstration reactor, aroad map toward construction, and select a site, at an earlystage in addition to the early resumption of “Monju”. MHIis determined to promote a commercial FBR, establish
the technology on a industrial level, and contribute to theprogress of society, while being committed to furthering
the maintenance and handing down of technology in parallelwith the development and reinforcement of human resources
to meet the urgent needs of the times in cooperation with
the JAEA.

5. Efforts associated with international standardization
In recent years, not just in Japan but worldwide, thenecessit y for t he development of F BR s is becom i ng
more recognized, reflecting the concepts of the effective
utilization of uranium resources as well as the reduction inradioactive waste.
In the Generation IV Reactor Project, an international
project in which 10 countries and the EU are taking part,the FBR cycle has been nominated as a major candidate forthe future. A demonstration reactor, BN-800 (800 MWe),in Russia, a prototype reactor (500 MWe) in India, andan experimental reactor (25 M We) in China are underconst r uct ion a iming at commercial operat ion around2030 pursuant to their respective national policies for thedevelopment of the FBR cycle. 9On the other hand, in the U.S.A., the Global Nuclear
Energy Partnership (GNEP) program was presented by
the Department of Energy (DOE) in 2006 to express thenecessity for fast reactors (advanced recycling reactors).10The DOE invited package proposals for advanced recycling
reac t or s t o for m t he t e ch n ic a l core of t he prog r a malong with the Consolidated Fuel Treatment Center for
reprocessing spent nuclear fuels in order to bring about
the GNEP program. 11 MHI made a proposal for GNEP
program in cooperation with A REVA and Japan Nuclear
Fuel Ltd., and it was successfully awarded. MHI aims at thestandardization of the sodium-cooled loop type large-scale
FBR, the principal concept originating in Japan, to become
the leader of the design and development of advanced
recycling reactors, and is currently investigating theadvanced recycling reactor in this line.
It is anticipated that from now on FBR development will
be promoted as an international collaborative researchand development theme and MHI will further increase its
share of international cooperation under the guidance of thegovernment, JAEA and power utilities.

References
1. Atomic Energy Commission of Japan, “Framework for Nuclear EnergyPolicy” (2005)
2. The 53rd Council for Science and Technology Policy, Science andTechnology Basic Plan, promotion strategy for each area (2006)
3 . Ja p a n’s Nucle a r E ne r g y Na t ion a l P l a n , Nucle a r E ne r g y
Subcommit tee, Elect r icit y I ndust r y Commit tee, Adv isor y
Committee for Natural Resources and Energy (2006)
4. Japan Atomic Energy Agency, The Japan Atomic Power Company,“ Feasibilit y St udy on Commerciali zed Fast Reactor Cycle
Systems -Phase II Final Report-” JA EA-Evaluation 2006 - 002(2006)
5. MEXT Committee on Research and Development in Nuclear
Energ y F ields , “ On R es e a rch a nd Development for Fa stBreeder Reactor Cycle - Responding to the “Feasibility Study on
Commercialized Fast Breeder Reactor Cycle Systems - Phase IIFinal Report -” (2006)
6. MEXT, METI, FEPC, JAEA, “R&D organization for demonstration fastbreeder reactor (FBR) in the pre-design phase” (2006)
7. MEXT, METI, FEPC, JAEA, “Selection for a Core Company tobe engaged in Engineering Activities for Fast Breeder Reactor
Development” (2007)
8. Ito, Satoh, et al., “Mitsubishi Activities for FBR CommercializationDevelopment” MHI Technical Review Vol.43 No.4 (2006)
9. Atomic Energy Commission of Japan, 52nd Regular Meeting,“Reference Materials Relating to R&D of FBR Cycle Technologies”(2006)
10. Internet website of United States Department of Energy:
http://www.gnep.energy.gov/
11. United States Department of Energy, “FOA Financial Assistance Funding
Opportunity Announcement” (2007)

6. Conclusion

Naoto Motooka

MHI has participated in the national project since its
initial stage recognizing the importance of FBR cycle andhas cultivated technology across the broad range of FBR
plants through its experiences with “Joyo” and “Monju”, thedesign study of demonstration reactors, and so on. MHI
proposed a sodium-cooled, loop-type, large-scale FBR to be

Hiroyuki SatoTakaya Ito

Shigeru Kunishima

Mitsubishi Heavy Industries, Ltd.
Technical Review Vol. 45 No. 1 (Mar. 2008)

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