2

Research and Development of Advanced Nuclear System

R&D of Fast Reactor Cycle Technology
R&D of FR Cycle Technology

R&D in “MONJU”◆ International Standardization of Safety
Design Requirements◆ Fundamental R&D
Experimental
Fast Reactor“JOYO”

ChemicalSodium-cooled
Fast Reactor Processing Facility
Concept

Development of SDC

Prototype Fast Breeder Reactor “MONJU”

Experience with theaccident at 1F*

International
Cooperation

Reflection of the SA measures thattake into account lessons from theaccident at 1F* to SDC

Plutonium Fuel
Production Facility◆ Demonstrating the Reliability ofan Operational Power Plant◆ Establishing Sodium HandlingTechnologyPlanning of International
Joint Experiment

Enhancement of SA
measures in “MONJU”

International Workshop on
International Collaborative
Research using “MONJU”*1F: The Tokyo Electric Power Company, Incorporated Fukushima Daiichi Nuclear Power Station

Fig.2-1 Overview of research and development of fast reactor cycle technology
We are implementing activities related to international standardization of safety design requirements and conservation of the technical basis
as efforts for the near term until national policies are reconsidered. As part of these efforts, we are promoting research and development
utilizing international cooperation, such as development of the SDC and planning of an international joint experiment on safety issues.

Until FY 2011, research and development activities wereconducted toward the commercialization of fast reactor cycle
technology with the cooperation of the electric utilities; the main
target was the concept of a combination of a sodium-cooled
fast reactor, advanced aqueous reprocessing, and simplified
pelletizing fuel fabrication. Currently, national policies arebeing reconsidered because of the impact of the accident at
the Tokyo Electric Power Company, Incorporated Fukushima
Daiichi Nuclear Power Station (1F). In accordance with thesituation, we have implemented activities focused on the efforts
required for conservation of the technical basis and international
standardization of safety design requirements for the near term
utilizing international cooperation, while reflecting the experience
gained in the accident at 1F (Fig.2-1). In May 2013, the Safety
Design Criteria (SDC) that we proposed were approved at theGeneration-IV International Forum (GIF). This chapter describes
the resulting enhancement of the safety and reliability considering
the features of a sodium-cooled fast reactor and basic research on
fuel cycle technology.
The Japan Sodium-cooled Fast Reactor (JSFR) is designed
to have high resistance against earthquakes and tsunamis byadopting a seismic isolation system for the reactor building anda natural convection capability for cooling after an abnormal
shutdown (Topic 2-1).
Regarding an ultrasonic flowmeter for the cooling system, ameasure that enables precise measuring results to be obtainedeven for flows exhibiting great spatial and temporal variation
was identified. The result shows that the ultrasonic flowmeterhas the potential for adoption in the plant system (Topic 2-2).
To develop an under-sodium viewer aimed at visual andvolumetric inspection of the internal structures in a reactor vessel,
data were obtained to justify the present improvement measurewith regard to wetting of the ultrasonic sensor surface by liquidsodium, which affects the sensor performance (Topic 2-3).
The strength properties of 316FR and Modified 9Cr-1Mo
steel, which are adopted as structural materials for JSFR, wereformulated on the basis of an evaluation of the material test
data. This makes the structural design more reliable (Topic 2-4).
Regarding sodium/water reaction, which is an importantissue for ensuring the safety and protection of the steam
generator, experiments were conducted as a joint study with theCommissariat à l’Énergie Atomique et aux Énergies Alternatives(CEA), France. A reaction jet that was produced during heattransfer tube failure and the effect on the resistance characteristics
of a heat transfer tube were evaluated (Topic 2-5).
With respect to basic research on the fuel cycle, the oxygento-metal ratio, which significantly affects various physicalproperties of uranium–plutonium mixed oxide fuel, such as
the thermal conductivity, could be controlled at will. These
technologies became applicable to fuel fabrication andirradiation behavior evaluation (Topic 2-6).

JAEA R&D Review 201333