Wall-tube flange refurbishment for securing gas-tightness of telemanpulators in the ACPF hot-cell

ACPF (Advanced spent fuel Conditioning Process Facility) was constructed in the basement of the Irradiated Materials Examination Facility (IMEF) at KAERI (Korea Atomic Energy Research Institute) in 2005. ACPF, an alpha-gamma type hot-cell, was operated in an air atmosphere. The gas tightness of the three-piece telemanipulator in the ACPF hot-cell is achieved through the contact between the wall-tube flange and the two o-rings seated in the through-tube flange. The wall-tube flange surfaces were rough and damaged after dismantling the one-piece telemanipulators from the ACPF hot-cell. The front surfaces of the wall-tube should be refurbished so that the tightness between the wall-tube flange and the through-tube flange can be secured. This refurbishment included the flange surface machining of the wall-tube such as drilling, tapping, grinding, and tightness identification in sequence. A total of ten wall-tube flanges were machined. For each wall- tube flange surface, six holes were accurately drilled and tapped at intervals of 60 degrees so that the through-tube flange of the telemanipulator can completely fit into the wall-tube flange. The flange surface was ground flat enough using specially designed tools to secure a complete gas-tightness. Three-piece telemanipulators were installed through the refurbished wall-tube in the refurbished ACPF hot- cell. Currently, telemanipulators are under use by conducting various types of remote tasks in the refurbished ACPF hot-ell