PASSIVE SHUTDOWN SEALING DEVICE FOR A SHAFT SEALING SYSTEM OF A REACTOR COOLANT PUMP SET

摘要

This invention relates to a passive shutdown sealing device (20, 40) for a reactor coolant pump set comprising a set of bimetallic strips (21, 41) having a first position called the cold position when the temperature of said bimetallic strips is less than said temperature threshold, and a second position called the hot position when the temperature of said bimetallic strips is greater than said temperature threshold; a sealing ring (23) with an active position when said bimetallic strips (21, 41) are in their hot position and with an inactive position when said bimetallic strips are in their cold position; locking/unlocking means (25) adapted to lock said sealing ring (23) in its inactive position when said bimetallic strips (21, 41) are in their cold position and to release said sealing ring (23) when said bimetallic strips (21, 41) are in their hot position; elastic means (24) adapted to constrain said sealing ring (23) in the active position when said locking/unlocking means (25) are unlocked.