Feedback from Operating Experiences
Beginning in the 1970s, fast reactors have been launched in various countries for R&D and experiment purposes. After generating the essential data, getting industrial and operation experience from sodium components, prototype sodium-cooled fast reactors (SFRs) were deployed in a few countries. Especially in France, a large-size fast reactor of 1200 MWe, Superphénix, was commissioned. All of the world’s fast reactors combined have accumulated more than 400 years of reactor operating experience, yielding rich data on the behavior of fuel, fuel safety, sodium components, steam generators, fuel handling equipments, etc. Small experimental reactors, for example, EBR-II, Rapsodie, BOR-60, JoYo, and fast breeder test reactor (FBTR) have provided valuable experience on sodium technology, fuel element design involving fuel choice, cladding and wrapper material, burnup limit demonstration, and material irradiation data. In particular, EBR-II was extensively utilized in the development of sodium-bonded metal fuel. The objective of the U.S. fast reactor program with U-19Pu-10Zr ternary sodium-bonded metal fuel has been successfully demonstrated in EBR-II and the Fast Flux Test Facility (FFTF). With respect to reactor assembly and other components, however, these small reactors are limited in demonstrating structural integrity requirements of commercial fast reactors because the design loading, in particular thermal loading, increases with the size rating of the components. When initiating the design of a new reactor, every design organization considers it prudent to utilize feedback from operating experience. This was done when Superphénix in France and the prototype fast breeder reactor (PFBR) in India were designed, and a similar approach was taken with the design of the European fast reactor. The International Atomic Energy Agency (IAEA) has also contributed to feedback exchange through annual meetings of the International Working Group on Fast Reactors, technical meetings on specific topics, and publications on fast reactor technology. The IAEA has also undertaken work related to knowledge management of fast reactor experiences. SFRs are favored candidates for sustainability of nuclear energy by answering to limited resources of uranium and high-level-waste management by incineration of minor actinides and long-lived fission products. The summary of operation of fast reactors worldwide is given in Table 27.1 for small reactors and in Table 27.2 for medium-sized reactors [27.1].