ENCAPSULATION OF FUEL RODS FOR TRANSPORT

The package NCS 45 is licensed for the transport of fuel rods with a burn-up of up to 120 GWd/MgU. Fuel rods with a burn-up of more than 62 GWd/MgU must be encapsulated, with even more stringent requirements in USA. The cans must not contain free water and must be sealed by welding or an adequate method. The production of welded cans in Hot Cells is standard practice. However, the encapsulation of fuel rods in a fuel assembly pool was not possible in the past. For this problem NCS developed a solution (pat. pend.) comprising an encapsulation device, cans and a proper process to produce sealed and dry cans containing fuel rods under water. In this NCS process a brazing method is used to seal the cans. A trial installation has been built and test cans were produced to validate the encapsulation process including drying and leak-testing. A qualification program was established and carried out successfully and at the time of PATRAM the production installation is being manufactured.