Design and application of a special underwater cutting device for the decommissioning of the first HWRR reactor in China

Abstract

The Heavy Water Research Reactor (HWRR) labeled 101 is the first nuclear reactor in China and the first large scale research reactor to be decommissioned in China. In the first phase of decommissioning, all spent fuel assemblies need to be removed from the spent fuel storage pool and transported to the spent fuel reprocessing plant through the RY-I transport container. The spent fuel storage pool can undergo further comprehensive cleaning and refurbishment. The HWRR reactor has operated for about fifty years, various experiment projects and several large scale upgrades were undertaken during its operation, the types and forms of spent fuel assemblies are relatively complex. Due to the deformation of the corrugated plates of some spent fuel assemblies, these spent fuel assemblies cannot be removed from the external process tubes according to the normal operation. Therefore, this paper designed a special device for the underwater cutting of the process tubes based on the structure of the process tube and spent fuel assembly, which successfully completed the underwater cutting of process tubes and the retrieval of twenty spent fuel assemblies, so all the spent fuel assemblies in spent fuel storage pool of HWRR reactor are taken out and shipped out. This device and technology provide technical reference for the underwater cutting of highly radioactive metal pipelines in other research reactors and nuclear power plants, and it can also improve the technical system and capacity for the decommissioning of the nuclear facilities in China.