Proposal of maintenance rationalization for next-generation fast reactors based on the analysis of the prolonged maintenance of the prototype fast-breeder reactor in Japan, "Monju", 2; Analysis of maintenance plan of "Monju" in reactor cold shutdown

Toyota, Kodai; Hashidate, Ryuta; Takahashi, Keita; Yada, Hiroki; Takaya, Shigeru

Hozengaku, 20(2), p.95 - 103, 2021/07

Prototype fast breeder reactor Monju; Its history and achievements (Translated document)

Mitsumoto, Rika; Hazama, Taira; Takahashi, Keita; Kondo, Satoru

JAEA-Technology 2019-020, 167 Pages, 2020/03

JAEA-Technology-2019-020.pdf:21.06MB
JAEA-Technology-2019-020-high-resolution1.pdf:47.3MB
JAEA-Technology-2019-020-high-resolution2.pdf:34.99MB
JAEA-Technology-2019-020-high-resolution3.pdf:48.74MB
JAEA-Technology-2019-020-high-resolution4.pdf:47.83MB
JAEA-Technology-2019-020-high-resolution5.pdf:18.35MB
JAEA-Technology-2019-020-high-resolution6.pdf:49.4MB
JAEA-Technology-2019-020-high-resolution7.pdf:39.78MB

The prototype fast breeder reactor Monju has produced valuable technological achievements through design, construction, operation and maintenance over half a century since 1968. This report compiles the reactor technologies developed for Monju, including the areas: history and major achievements, design and construction, commissioning, safety, reactor physics, fuel, systems and components, sodium technology, materials and structures, operation and maintenance, and accidents and failures.

Analysis of issues related to maintenance period of the fast breeder prototype reactor Monju, 1; Analysis of plant operation for maintenance of cold shutdown Monju

Hashidate, Ryuta; Toyota, Kodai; Takahashi, Keita; Yada, Hiroki; Takaya, Shigeru

no journal, , 

In order to achieve both safety and economic efficiency of a nuclear power plant, it is necessary to realize rational maintenance based on characteristics of the plant. The fast breeder prototype reactor, Monju, spent most of the year for the maintenance. It is important to identify causes of the prolonged maintenance of Monju and to investigate countermeasures for implementation of rational maintenance of a next fast reactor. In this study, causes of the prolonged maintenance of Monju during reactor cold shutdown were investigated based on the plant operation of Monju. In addition, proposals for the maintenance optimization idea of a next generation fast reactor were presented to address the revealed issues.

Fundamental study on optimal scheduling of inspection process for fast reactor

Suzuki, Masaaki*; Ito, Mari*; Hashidate, Ryuta; Takahashi, Keita; Yada, Hiroki; Takaya, Shigeru

no journal, , 

Optimal scheduling of inspection process for fast reactor via integer programming

Suzuki, Masaaki*; Ito, Mari*; Hashidate, Ryuta; Takahashi, Keita; Yada, Hiroki; Takaya, Shigeru

no journal, , 

Development of inspection process scheduling system for analyzing operability of fast reactor

Suzuki, Masaaki*; Ito, Mari*; Hashidate, Ryuta; Takahashi, Keita; Yada, Hiroki; Takaya, Shigeru

no journal, , 

Maintenance scheduling is currently manually handled, which is a time-consuming process because of the large number of components and constraints that must be taken into account when creating a schedule. Besides, to develop next-generation power plants with excellent operability, it is necessary to make it possible to evaluate operability and maintainability in advance at the design stage. Our objective is to develop and implement an automatic scheduling system using the mathematical technique of Operations Research for addressing the inspection process scheduling problem in a sodium-cooled fast reactor plant. This study constructs a scheduling model that performs optimization in two stages to reduce the computation costs.

Under sodium visualization technique using ultrasonic and its application

Takahashi, Keita; Yamaguchi, Toshihiko; Saito, Junichi; Ueda, Masashi; Nakaishi, Sumitaka*

no journal, , 

In order to visualize the phenomenon under opaque liquid sodium, which is coolant of fast reactors, we tried to made an ultrasonic visualization device. A buffer rod was implemented to cope with high temperatures, and as a result of improvements in frequency, shape, etc., a resolution of 0.5 mm was obtained under sodium. Using this device, the transmittance of ultrasonic waves at the interface between liquid sodium and stainless steel was investigated. As the result, it was confirmed that the temperature of sodium and the roughness of the surface of stainless steel affect the transmitting behavior of ultrasonic waves.

Analysis of inspection process schedules for sodium cooled fast reactors using swarm intelligence

Suzuki, Masaaki*; Ito, Mari*; Hashidate, Ryuta; Takahashi, Keita; Yada, Hiroki; Takaya, Shigeru

no journal, , 

In order to achieve a smooth operation that balances safety and economic viability in next-generation reactors, it is essential to implement a design that considers maintenance. Currently, there is a lack of technology to repeatedly assess operability during the pre-construction phase and identify design aspects that pose challenges to maintenance, creating a bottleneck in the process. This study employs swarm intelligence techniques to learn and analyze inspection process schedules that satisfy various constraints in sodium-cooled fast reactors.