Investigation of technologies on structure and materials that contribute to the reduction of construction cost and elongation of design life of FBRs

not registered 

For the commercialization of FBRs, not only construction cost but also maintenance cost must be reduced. At the same time, design life should be extended. For this purpose, elevated temperature design standard has been successively updated and new materials have been developed. However, more efforts are necessary to make FBR competitive against advanced LWRS. From this viewpoint, this report widely surveyed innovative technologies that had not been assessed in the current effort for the improvement of the design standard but were considered to be able to contribute to cost reduction. Areas investigated were specification and fabrication of structural material, design evaluation, fabrication, inspection, operation and maintenance. Promising technologies were selected from the result and the extent of improvement of the design of the intermediate heat exchanger of the so-called "Demonstration Reactor Phase I Design Study" was quantitatively evaluated; the allowable stress level calculated by elastic analysis can be roughly doubled and the design life of 60 years was envisaged. Moreover, a new concept of design standard that is indispensable to utilize the above promising technologies in actual plant designs without decreasing reliability. The new system of codes and standards must cover not only design evaluation but also specification and fabrication of structural material, fabrication inspection, operation and maintenance. At the same time, it must show quantitatively the safety margins that must be made and the way to achieve it so that the cost be minimum as well.