Leak monitoring for sub:atmospheric nuclear fuel element storage tube - by bellows which compresses to actuate alarm signal

摘要

A short length of pipe (6) comprising a bellows section (7) and having a closed inner end (8) is fixed and sealed, esp. welded, at its open end in an opening in the vessel wall (2). A pin (9) passing into the pipe is fixed to the inner, closed end (8) and slides in the bore (10) in the vessel wall. If the pressure inside the vessel rises, the bellows is compressed and the pin (9) moves out from the vessel to actuate an alarm or signalling mechanism. The method provides a reliable long-term surveillance system requiring minimum maintenance and responding reliably to an increase in the internal pressure.