Objective
The purpose of this project was to supply a machine to tighten and untighten in the most efficient way possible the nuts and studs of the steam generators in order to reduce the exposure to radiation to a minimum and to assure an optimum of tightness.
The common principle of the proposed equipment was to put tension on the studs before nut rotating to prevent difficulties when torquening and to assume adequate effort from the tightened studs on the cover. The force is generated in such a tool by high pressure hydraulic.
There are different working principles of such equipment, used by various manufacturers. Tensioning force was to be controlled by hydraulic pressure. The resulting stud elongation was to be monitored.
Result
A stud tensioning machine for the Steam Generator has been purchased and delivered to Kalinin NPP.