DIFFERENTIAL PRESSURE BASED LOCK

摘要

A lock for securing the head of a fuelling machine, defuelling machine or inspection machine to the end fitting of a fuel channel of a nuclear reactor is a rod and piston lock which engages or disengages according to the differential between the pressure in the snout cavity and the pressure in the fuelling machine magazine. The lock is engaged when the snout cavity pressure and the fuelling machine pressure are substantially equalized. When the pressure in the snout cavity is reduced sufficiently below the level of the pressure in the fuelling machine, the lock is engaged. The lock remains engaged if there is a drop in reactor pressure during refuelling and during reactor shutdown conditions. Engagement of the lock prevents inadvertent unclamping of the fuelling machine from the fuel channel.