Pressurised water reactor stam line shutdown after burst duct - with valve system permitting rapid location of burst

摘要

A pressurised water reactor comprises =1 steam generating unit and two steam lines passing through the safety containment has a quick shutdown valve in each line inside the containment and a safety valve in each line outside the safety containment. The two steam lines are cross-connected downstream of the shutdown valves via a three-way valve and a throttle, the third connection of the three-way valve being connected to a bypass leading to a point in the steam line upstream of the shut-down valves, in normal operation, the three-way valve has this third connection set in a central posn. so that it is connected to both the other outlets of the valve. In a preferred arrangement comprising two steam generating units, there is a symmetrical arrangement comprising two cross-connecting lines, each contg. a three-way valve, the third connection of each of these valves being led back to only one steam generating unit. Pref. there is also a non-return valve, in each cross-connecting line and pref. also a pressure-dependent valve in each of these cross-connecting lines. If a rupture occurs in a main steam line, pressure relief of the steam generating units takes place through the throttles and the resultant difference in the pressure drops enables the rupture to be rapidly located.