DEVICE HAVING PASSIVE-AUTOMATIC FLOW-LIMITER FOR ELIMINATING WATER BAG OF HOT BRANCH IN PRIMARY CIRCUIT OF PRESSURIZED-WATER REACTORS

In some pressurised water reactor systems primary cooling circuits are used whose hot branch has a low point such that during some upset conditions a stoppage of the water flow may develop. In some upset conditions, primarily after small breaks in the pipes, the cooling of the active zone could be threatened. The proposal is based on the provision of an anti-lock pipeline which is equipped with a 'passive' system of flow control, which opens automatically during any upset condition. Normally this system will reduce the flow in the anti-lock pipe to a negligible level. In an upset situation water from the hot branch will be automatically transfered to the cold branch. The equipment does not require any external signal or energy source for its control and operation, hence it is passive and automatic. The proposal may be implemented in various ways, the following may be used:-Hot brnach depression unit, cold branch pressure element, ejector using the energy of the water from the high pressure region of the cold branch and hydro-mechanical flow prevented using the same pressure energy.