4 - Demonstration and commercial plant design study

Abstract

Following the development of the experimental reactor Joyo and the prototype reactor Monju, several design studies of large-scale SFR plants were conducted in Japan, which includes a demonstration plant design by the utilities and a 1500 MWe SFR that is named Japan sodium-cooled fast reactor (JSFR) as a commercial plant jointly by JAEA, the utilities, and the industry.1.Demonstration reactor project: A demonstration fast breeder reactor “DFBR” project was carried out primarily by industries, namely utilities and manufacturers. However, due to both domestic and international circumstances, the DFBR project was canceled.2.JSFR in FaCT project: As a commercial plant concept in the FaCT project, JSFR with a capacity of 1500MW was developed. MOX fuel was studied as a reference for the core, but metal fuel was also considered as an option. JSFR employs several innovative key technologies to achieve high safety and economic targets, and these innovative technologies were evaluated in terms of maturity before moving forward with further development steps such as conducting large-scale demonstration tests, basic design, and detailed design of a demonstration reactor. For the demonstration reactor, a comparison of reactor output between 500 MWe and 750 MWe was conducted and 750 MWe was selected. The AtheNa sodium test facility was constructed to conduct component and system demonstration tests for the large-scale demonstration test.3.Safety improvement: Since 2011, to contribute to the development of safety design criteria and safety design guidelines, in the framework of the Generation IV International Forum (GIF), a design study on the 750 MWe demonstration JSFR enhancing safety and maintainability was conducted, which included lessons learned from the TEPCO’s Fukushima Daiichi nuclear power plants accident (the 1F accident).4.Pool-type SFR: International collaboration on ASTRID was initiated in 2014, and a design study of a pool-type concept accumulating knowledge from the ASTRID collaboration was conducted showing feasibility even against Japanese severe seismic conditions.