Progress and Development Thinking of Dry Reprocessing Technology for Spent Nuclear Fuel from Fast Reactor

Dry reprocessing for spent nuclear fuel refers to a chemical process that involves treating spent nuclear fuel in non-aqueous media, recovering actinide elements such as uranium and plutonium, and properly disposing radioactive waste. It is a key step in closed fuel cycle of fast reactor nuclear energy systems and a practical technical choice for spent nuclear fuel reprocessing from fast reactors. Both the United States and Russia have mastered the dry reprocessing technology for spent nuclear fuel in fast reactors, and have established dry reprocessing process flows suitable for their own fast reactor nuclear fuel cycle strategies. After engineering scale hot testing verification, engineering technology is being developed. The selection of China’s dry reprocessing technology route follows international advanced technology and the overall strategy of China’s fast reactor fuel cycle, with a focus on the development of molten salt electrolysis technology, which is compatible with the treatment of many types of fast reactor spent nuclear fuel, such as oxides and metals. It is currently in a critical stage of technological research and development. An overview of the typical process and development trends of dry reprocessing technology for spent nuclear fuel in fast reactors was provided in this paper. The latest progress made in the research and development of dry reprocessing technology for spent nuclear fuel from fast reactors in China was summarized. The challenges faced by the dry reprocessing technology were analyzed, and the key scientific and technological issues urgently needed to be addressed in the development of dry reprocessing technology of fast reactor spent nuclear fuel in China were proposed in combination with the development strategy of fast reactor nuclear energy system in China. Based on the fact that transmutation of minor actinides is one of the main functions for the fast reactors in China, the dry reprocessing technology process needs to consider the recovery of all actinides, including minor actinides. At the same time, it is also necessary to consider the treatment of both metallic and oxide spent nuclear fuel. Thus, the molten salt electrorefining technology has been selected to meet the requirements. At present, the conceptual design of the dry reprocessing demonstration plant has been completed, and key technology research has been carried out. Minor actinides are recovered simultaneously in the main process, meeting the requirements of the full actinide cycle in the fast reactors. The flow sheet of dry processing was established with the recovery rates of 99% for uranium, 99.5% for plutonium and minor actinides. With the recycle of the molten salt, 90% of the salts can be reused.