We must establish methods for efficient utilization of Uranium resources to supply reliable and constant nuclear power. Appropriate technologies might include fast reactor and nuclear fuel cycle. We have been developing such technologies.
We engaged in the design and construction of Experimental Fast Reactor Joyo and Prototype Fast Breeder Reactor Monju.
As a major equipment manufacturer, we will continue to contribute to progress and the practical application of fast breeder reactors.
Experimental Fast Reactor Joyo
Prototype Fast Breeder Reactor MonjuPhotos courtesy of Japan Atomic Energy Agency (JAEA)
The Rokkasho Reprocessing Plant is Japan’s first commercial nuclear fuel cycle facilities constructed by Japan Nuclear Fuel Limited (JNFL). As it approaches the beginning of its operations, we participate in EPC to conform it to the new regulatory requirements. We are thus working to establish a safer nuclear fuel cycle and the stable operation of nuclear plants.
Excerpt from the website of Japan Nuclear Fuel Limited (JNFL)
Spent fuel receiving and storage building: Cools down and temporarily stores fuel assemblies that have been brought to the reprocessing plant until their radioactivity has decreased sufficiently.
Cuts cooled fuel assemblies into small pieces with a shearing machine and dissolves them in a dissolver containing nitric acid. Undissolved residue (metal chips such as cladding tubes) is removed from this nitric acid solution containing dissolved fuel meats using a clarifier.
Separates the dissolver solution generated in the previous process into uranium stream, plutonium stream, and fission products’ stream.
Removes the small amount of residual fission products from the uranium and plutonium solutions for purification.
Removes nitric acid from the purified uranium solution and the mixed uranium/plutonium solution to produce uranium oxide powder and uranium/plutonium mixed oxide powder.
Our products are delivered mainly for the spent fuel receiving and storage building, the separation building, the purification building, the low active liquid waste treatment building, and the control building.
We delivered the following facilities and equipment to the spent fuel receiving and storage building.
We delivered the following equipment to the head end building, where cooled spent fuel assemblies are sheared and dissolved.
Dissolution off-gas treatment facility removes volatile radionuclides (iodine) from dissolution off-gases by absorption.
Iodine removal column (made of pure zirconium) with an approximate height of 6 meters
Fission products in the dissolver solution transferred from the previous process are separated from uranium and plutonium by contacting with an oil-based solvent (solvent extraction) in the separation facility, and then uranium/plutonium are further separated into each stream in the distribution facility.
We delivered the following facilities and equipment to this building.
High Active Liquid Waste concentrator:A principal device in the separation building, concentrating and reducing volume of the high active effluent that contains almost all fission products in nuclear spent fuels
The refining building, where refining is carried out, removes the small amount of fission product contained in the uranium solution and plutonium solution more finely to improve purities.
We delivered the following equipment to this building.
Acid recovery evaporator (gas/liquid separator part) : A principal device in the separation and purification building, recovering nitric acid from nitric effluent generated after removing uranium, plutonium and other substances from nuclear spent fuels
Each process in the reprocessing plant is centrally operated and monitored from a control room in the control building.
We delivered a distributed control system based on highly reliable, operable and maintainable technologies that have been well cultivated through experience with light-water reactors.
Central control room in the reprocessing plant(Source: the Japan Nuclear Fuel Limited (JNFL))
Products before shipment from the factory
For stably supplying electric power generated from nuclear energy, it is necessary to establish technologies for effectively using uranium resources. Fast reactors for effectively using uranium and nuclear fuel cycle technology fall under the technologies that we are working to develop.
We are moving forward with the development of the FLUOREX method*1 for reprocessing using the fluoride volatility method as a next-generation reprocessing technology. It takes advantage of differences in the vapor pressure of fluorides to recover uranium and plutonium with high efficiency and purity. It features low waste emissions and high economic efficiency.
We are working to develop technology to separate nuclear fuel substances and radioactive waste using the fluorination process based on the fluoride volatility method developed as a next-generation processing technology. It is aimed at attaining rational management of fuel debris generated from the Fukushima Daiichi Nuclear Power Station and waste generated from fuel debris retrieval.
"Transportation" of spent fuel from the nuclear power plant to medium-term storage, "storage" at the medium-term storage facility, and "re-transportation" from the medium-term storage facility to the reprocessing facility. We have developed Transport and Storage Dual Purpose Metal Cask product for these three functions that combines long-term reliability with good economics.
From Federation of Electric Power Companies web site (partially modified)
Interim storage facility(From Recyclable-Fuel Storage Company web site)
In the early stage of the development process, we implemented analyses, studies and a variety of tests on their safety and durability at the time of transport and confirmed that they met the functional requirements.
Transport and Storage Dual Purpose Metal Cask