POSITION DETECTING DEVICE FOR MAIN STEAM LINE PLUG

摘要

PURPOSE: To detect the thrust position and drift position of a plug main body by detecting that a moving body supported by a bracket is relatively moved by a fixed distance in the opposite direction or the same direction as the inserting direction of a main steam line plug. CONSTITUTION: When a position inspecting device 10 is moved by a fixed distance, the tip of a rod 12 collides with the inner face of a reactor pressure vessel 2 around a main steam nozzle 3. The inspection device 10 is further moved integrally with a plug main body 4, a guide housing fixed to a bracket 11 and detecting means 14, 15 are moved in the same direction, the tip of the rod 12 is kept in contact with the inner face of the reactor pressure vessel 2, the movement of the plug main body 4 in the inserting direction is restricted, and it is stopped while pressing a spring 13. When the rod 12 is relatively moved by the fixed distance after it collides with the inner face of the reactor pressure vessel 2, a plate 21 to be detected reaches the detection position of the detecting means 14, and it can be detected that the plug main body 4 is moved by the fixed distance in the inserting direction after the tip of the rod 12 collides with the inner face of the reactor pressure vessel 2.