ENCAPSULATION OF NUCLEAR SPENT FUEL FOR SEMI-DRY STORAGE AT THE BUDAPEST RESEARCH REACTOR

摘要

In order to change the temporary underwater storage mode of nuclear spent fuel (NSF) from wet to semi-dry as a means of slowing down or even stopping the corrosion effects of the cladding and thereby ensuring safe storage conditions for further temporary storage, AEKI's experts elaborated a canning technology and canning equipment. Manufacturing of the canning equipment and the installation work at the 'away from reactor' (AFR) pond of the Budapest research reactor (BRR) were completed, and the regulatory licence for NSF encapsulation was granted in March 2002. The canning has been running since May 2002. As a first step, a verification programme was performed during which both the technology and the canning equipment were verified and adjusted. Then, during the regular canning programme in 2002, we completed the encapsulation of all our EK-10 fuel (82 fuel assemblies were encapsulated) and at present we are canning the VVR-SM and -M2 type NSF. Until the end of September 2003, 135 single VVR NSF assemblies and 115 triple VVR ones had been encapsulated together with the 82 EK-10 assemblies mentioned. The focus of the paper is less on the wet storage problems of NSF and more on the canning technology and the canning equipment itself. Furthermore, a summary is provided of the experience gained during system commissioning, validation and during the regular canning procedure at the AFR pond of the BRR.