Siemens Nuclear Power has supplied an inspection manipulator for the Finnish plant Loviisa, which could halve the time required for eddy current testing of steam generator tubes, thanks to a dual pusher.
The inspection manipulator is used for remote-controlled positioning of various modules during in-service inspections in the steam generator headers. In contrast to its predecessors it is inserted fully assembled into the header with the aid of the reactor building crane and can be moved to the next header without any assembly work.
A double pusher comprises two combined equipment units and enables two tubes to be tested simultaneously.
An off-centre mast means that the centre of the header remains free, so the probe pusher unit or the tube repair modules can be positioned there. The redesign of the mast support also makes it possible to remove the pusher unit completely from the header. It has a quick-release coupling system to accommodate the inspection and repair equipment, so quick equipment changeover and adjustments to the eddy current testing systems are possible. For eddy current testing of the expanded section of the tubes and header ligaments, rotating and other probes can be inserted into the tubes by adjusting the pusher unit.