Pressurised water reactor with safety valve outside containment - to give easy access but connected upstream of internal cut-off valve

摘要

The parent patent describes a pressurised water reactor power plant comprising a safety containment, through which a steam line leads outwards, having one cut-off valve inside the containment and another cut-off valve outside it, with a safety valve upstream of the inner cut-off valve but discharging outside the containment. In the Patent of Addition, the safety valve is itself outside the safety containment and can be cut off by an internal cut-off valve. In a preferred embodiment, there is a second safety valve in parallel with the first, having a higher response pressure, also situated outside the containment, and pref. having a throttle upstream of it in the wall of the containment. The first safety valve may have a bypass blowdown line containing two cut-off valve in series. The safety valve serves the same function as in the Parent Patent, but being outside the safety containment is easily to maintain, on account of unrestricted access. Also, if the safety valve should fail, it can but cut off.