Abstract: To meet the conditioning requirements for highly radioactive solid waste, including end fittings and spent cladding generated during spent fuel assembly reprocessing, an engineering prototype of an efficient drying system for end fittings and spent cladding was developed. Based on an analysis of the heat and mass transfer mechanisms during the drying process and a comparison of common drying schemes, the process requirements and key functions of the drying system were identified. Following the process flow of “transfer → jacking and sealing → drying → detection,” the equipment modules and system layout were designed, and the engineering prototype was constructed. Tests on automatic compact drum transfer, waste drying, and remote disassembly and assembly of key components were carried out using the prototype. The key drying operating parameters were determined as follows: supply pressure of 0.2 MPa, supply flow rate of 130 Nm³/h, and initial supply temperature of 210 ℃; after 20 min, the supply temperature was adjusted to 190 ℃ for staged temperature control. The test results show that the system operates stably and reliably and meets the design requirements. A compact drum containing approximately 70 kg of end fittings and spent cladding with 3 kg of attached water can be dried within 60 min until the exhaust gas dew point is below -26 ℃. The results provide a basis for further optimization of the drying process. The developed drying system has good prospects for engineering application and can provide a technical reference for the design of similar spent fuel assembly reprocessing equipment.

Key words: end fittings, spent cladding, intermediate and high-level solid radioactive waste, drying equipment, remote disassembly and assembly